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Laboratory for the Certification of Asphalt Technicians

(LabCAT)

Level B - Plant Materials Control2020 Presentation Manual

In cooperation with the Colorado Asphalt Pavement Association,the Colorado Department of Transportation, and the

Federal Highway Administration

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STANDARD METHOD OF TEST FORVERIFICATION OF EQUIPMENT USED

TO TEST ASPHALT MATERIALS

CDOT CP 76 (CP -L 5101)LABORATORY EQUIPMENT

CP 76

This procedure covers the verification of equipment used to field test bituminous mixtures and provides documentation that the equipment verification has been done.

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CP-L 5101 Verification of Laboratory Equipment Used to Test

Bituminous Mixtures

• Superpave Gyratory

• Compression Machines

• Molds, Ram Heads, Base Plates, etc.

• Also covers gyratory maintenance

• Stabilometer, molds, followers, calibration cylinder

Both procedures contain schedules for maintenance, calibrations and verifications of equipment.

Questions????????????

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STANDARD METHOD OF TEST FOR REDUCING FIELD SAMPLES OF ASPHALT

MIXTURES TO TESTING SIZE

CDOT CP 55

SUMMARY

Asphalt mixtures must be sampled in accordance with CP 41 (T-168).

Samples must be split properly to obtain representative portions.

This procedure is valid for asphalt mixtures having a nominal maximum particle size of 1.5 inch (37.5 mm) or less.

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REPRESENTATIVE SAMPLES

To ensure representative samples:

Employ techniques that are intended to minimize variations in measured characteristics between the test samples.

Use proper equipment for the type of material to be reduced in size is important.

Equipment must also be used properly to produce representative samples.

SPLITTING METHODS

Method A-Selection by scoop

Method B-Quartering

Method C- Riffle type splitter

Method D-Selection by cross section

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PREPARATION FOR REDUCTIONTO USE METHODS A, B, D

Apparatus

Clean small flat square end scoop with sides.

Clean large flat bottomed mixing pan.

PREPARATION METHOD 1

Place sample into large, flat bottomed pan without loss of material.

Mix entire sample thoroughly 3 times.

Flatten to uniform depth equal to or lower than the sides of the scoop.

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PREPARATION METHOD 2

Place the sample can into the mixing pan with the opening resting on the bottom of the pan (upside down).

Elevate the can about 1 inch from the surface and move in a circular motion allowing the material to form a trail behind the can.

Try to distribute the material in two or more layers.

If visually segregated, mix the entire sample thoroughly and level as in Prep Method 1.

METHOD A-SELECTION BY SCOOP

Insert the scoop to full depth of the material.

Lift scoop with minimal loss of material.

Select a minimum of three increments.

Small portions may be cut with a putty knife or similar tool for small quantity additions .

Combine portions for test specimen of required mass.

Save remaining portion until tests are completed.

Shall not be used for combining & splitting large samples for testing between two or more labs.

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METHOD B -QUARTERING

Divide the sample into four equal quarters with scoop.

Remove two diagonally opposite quarters.

Re-mix the remaining two quarters.

Repeat procedure until sample is the required mass for the test specimen, save remaining portion until tests are completed.

This method may be used for combining & splitting large samples for testing between two or more labs.

METHOD C- RIFFLE TYPE SPLITTER

Splitters shall have a minimum of 8 chutes for coarse aggregates, 12 chutes for fine aggregates.

The minimum width of the chutes shall be approximately 50 % larger than the largest particles in the sample.

Place the sample in the mixing pan and mix thoroughly.

Two procedures for depositing samples into splitter:

➢ Flat scoop equal to width of riffles (feeder pan).

➢ Extra splitter pans

Shall not be used for combining &

splitting large samples for testing

between two or more labs.

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RIFFLE SPLITTER BY SCOOP (FEEDER PAN)

Remove material using the feeder pan.

Pour half of the portion from one side.

Reverse the ends of the feeder pan and pour the rest from the other side.

Pour slowly to allow a free flowing condition.

Continue until the entire sample has been introduced to the splitter.

RIFFLE SPLITTER BY SPARE PANS

Place the sample into two spare pans placed side by side with scoop.

Uniformly distribute the material from edge to edge.

Pour ½ of the material into the splitter .

Reverse the ends of the pan.

Pour the remaining material into the splitter.

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FEEDER PAN ORSPARE PANS METHOD

Reintroduce the portion of the sample as many times as necessary to reduce the sample to the size specified.

Use opposite pans for further reduction.

Save the remaining material for additional tests.

METHOD D-CROSS SECTION

Push a metal slat vertically through sample.

Push a second slat through sample parallel to the first.

Remove entire sample between the slats -take care to include all the fines on the tools.

Obtain additional samples by pushing one of the slats vertically into the remaining material and repeating the process.

Shall not be used for combining &

splitting large samples for testing

between two or more labs.

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QUARTERMASTER DEVICE

CP 55 states that this method may be used to split large samples for testing between two

labs.

NO Provisions are made for reducing the sample to testing size using this method.

QUARTERMASTER

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QUARTERMASTER

Used for combining & splitting large samples for testing between two or more labs

Splitter is to be clean and heated to not exceed 110 C degrees by a non-contact temperature device.

Pour samples into the hopper by using a continuous or segmented pour from multiple directions around the hopper

Rotate the sample cans in a clockwise direction after each split

Repeat until the specified sample size is achieved.

THE END

QUESTIONS??

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Standard Method of Testfor

Bulk Specific Gravity of Compacted Asphalt Mixtures Using Saturated

Surface-Dry Specimens

CDOT CP 44AASHTO T - 166

Purpose

◼ This procedure provides methods for determining bulk specific gravity to calculate the percent relative compaction of HMA and air void analysis.

◼ The Bulk Sp G is also used in determining the correlation factor for nuclear density gauges.

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Method A Laboratory Compacted Specimens for

100mm and 150mm Diameter Specimens

Testing Apparatus required

Balance, with suspension apparatus.

Wire of the smallest practical size at the penetration point of the water surface.

Water bath with overflow outlet.

Flannel or terry cloth towel

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Specimen Preparation

After removal from mold, allow specimen to cool to room temperature.

Place cooled, dry specimen on scale and record dry mass.

Immerse specimen in 77 +/- 1.8 F water bath for 4 +/- 1 minute.

Record immersed weight.

Remove specimen from water and quickly blot to SSD condition with a wet, freshly rung out terry or flannel cloth.

Quickly place specimen on scale and record the SSD weight.

Bulk Specific Gravity Calculation

where:

A = mass (in grams) of dry sample in airB = mass (in grams) of SSD sample, in airC = mass (in grams) of sample in water

GA

B Cmb =

-( )

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Percent Relative Compaction

100XGravitySpecificMaximum

GravitySpecificBulk

CompactionRelativePercent =

Air Voids (Va) Calculation

VaRice Bulk

Ricex=

−100

CompactionRelative%100VoidsAir

or

−=

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Convert Specific Gravity (Gs) to pounds per cubic ft (pcf)

CDOT uses:

Specific gravity x 62.4= pcf

Pcf / 62.4 = specific gravity

Questions ??

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Standard Method of Testfor Theoretical Maximum Specific Gravity of Asphalt Paving Mixtures

CDOT CP 51AASHTO T - 209

Purpose

This method covers the determination of the maximum specific gravity of un-compacted asphalt paving mixtures.

This method will assist with determining:

relative percent compaction

percent air voids

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Apparatus Required

• Balance, with ample capacity and sensitivity.

• Heavy walled volumetric flask or other container.

• Flat, transparent cover plate.

• Fine wire mesh .

• Calibrated thermometer, ASTM 17° C.

• Vacuum system, 3.7 ±0.3 kPa, (28 ± 2 mm Hg).

• Residual pressure manometer or pressure gauge.

Procedure

• Flask calibration.

• Sample preparation.

• Test.

• Calculations.

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Flask Calibration

• Perform once per month.

• Fill flask with water.

• Verify water temperature is 77 ± 1° F (25.0 ±0.5° C).

• Overfill flask and level off with cover plate.

• Determine and record the mass of flask, water and cover plate.

• Identify and record the flasks and cover plate(s).

• Average of last three determinations and record.

Sample Preparation

Samples shall be obtained according to (CP 41) T168.

Samples shall be split according to (CP 55) T- 248.

The sample size is based on the nominal maximum aggregate size of the mixture (Table 51-1).

Two separately taken identical test specimens shall be obtained and not recombined at any time.

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TABLE 51-1:Required Sample Mass for Various Nominal

Maximum Sizes of Aggregate

Inches MM Specimens X grams

1.5 37.5 2 X 3000g

1 25.0 2 X 1500g

¾ 19.0 2 X 1000g

½ 12.5 2 X 750g

3/8 9.5 2 X 500g

No. 4 4.75 2 X 500g

Nominal Maximum Size of Aggregate

Number and Minimum Mass of Specimens

Voids Analysis

• If laboratory or field produced specimens are to be compacted for voids analysis using CP-L 5115, the specimens used to determine the theoretical maximum specific gravity should be short-term aged using the same procedure as the specimens being compacted.

• Specimens maintained at a temperature above 200° F (94° C) for 1 hr or more do not require additional aging.

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Sample Prep - Continued

• Separate the fine particles of each sample so that they are no larger than ¼”inch.

• Take care not to fracture mineral particles.

• If mixture is not sufficiently soft to be separated, mixture may be warmed only until they can be so handled.

• Cool samples to room temperature

Test

Tare flasks or record mass of each empty flask.

Place samples into flasks.

Record mass of each sample.

Fill flask with water to a minimum of one inch above sample.

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Test (continued)

If the potential presence of lime in asphalt mixture needs to be determined, add 2-4 drops of phenolphthalein alcohol indicator

Let rest 10 seconds, to show potential presence of lime

Remove entrapped air under a partial vacuum of 3.7 ± 0.3 kPa (28 ± 2 mm Hg) for 15 ± 2 minutes.

Agitate the samples and flasks at 2 minute intervals (for 15 ± 5 s) or continuously with mechanical device.

• Turn vacuum off, not faster than 8 kPa/sec (60 mm/s Hg).

• Fill flasks with water (@ 25.0 ± 0.5° C).

• Stir sample with rod, if necessary.

• Finish filing flask with 77° F water & slip lid onto flask.

• Place flask in 77 ± 1° F (25.0 ± 0.5° C) water bath.

• Bring the contents of the flasks to 25.0 ± 1.0° C (77 ± 1° F ), check for air bubbles, remove any found under the lid, replace lid, determine the mass of the flask, water, sample and cover plate for each sample.

• The mass shall be determined 10 ± 1 minutes after the vacuum is released

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Test (continued)

• In lieu of a constant temperature bath as per section 6.5, determine the calibration masses at various test temperatures.

• Determine the final temperature of the samples.

• Make the appropriate density corrections.

• This process should be used with all suitable containers, not just the glass flasks.

Test (continued)

If the aggregate is not completely coated:

CDOT- Follow Method A- Dry-Back

– to be used if uncoated particles settle to the bottom of the flask. (They have absorbed water during the partial vacuuming process).

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Calculations

Where:

A = mass of dry samples

E = mass of samples, water, flasks and cover plate(s)

D = calibration masses

The specific gravities must be within 0.011 of each other for a valid test.

GA

A D Emm =

+ -

Reporting Specific Gravity

• As per 10.1.1: The specific gravity of eachspecimen to the nearest 0.001

• The average specific gravity of two specimens to the nearest 0.001.

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Questions?

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Standard Method of Test forDetermining the Asphalt

Binder Content of Hot Mix Asphalt by the Ignition

Method

CDOT CP L 5120

Summary of Test Method

• Per section 3.1, the binder in an APM sample is burned by ignition at a temperature high enough to ignite the asphalt binder fraction (due to the use of different models of ignition ovens, 8.2 of procedure is incorrect, it is not always 538° C (1000° F)

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Summary of Test Method(continued)

• Binder content is calculated by:

• Dividing the mass loss of the specimen after ignition by the mass of the mixture before ignition.

• The application of the correction factor, and the subtraction of the % of any moisture found.

Summary of Test Procedure

This method determines the asphalt binder content by burning the binder off by ignition, the specimen gradation is then determined with the remaining aggregate residue.

Not to be used for determining binder content of cores or otherwise obtained samples from existing bituminous pavements.

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Overview

• Safety Issues

• Apparatus

• Sampling / Test Specimens

• Calibration

• Test Procedure

• RAP

Safety Issues

• Wear eye protection

• Wear long sleeves

• Wear clean, heat resistant gloves

• Location of furnace

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Apparatus

Forced air ignition furnace, that heats the sample by convection method or infrared heat source ignition method.

Internal scale units will determine and indicate when the sample reaches a constant weight.

There must be an internal balance thermally isolated from the furnace chamber that is readable to 0.1g.

Thermolin

e (NCAT)

Calibration

• Correction factors will be determined for the binder content and the aggregate loss.

• These factors will be determined for each mixture design and when mix ingredients change.

• This method may be affected by the type of aggregate in the mixture.

• A calibration factor must be performed prior to any acceptance testing.

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Calibration Process

• The calibration process should be repeated each time there is a change in the mixture ingredients.

• Prepare three samples proportioned according to the JMF.

• Step One - Perform gradation analysis on an unburned “blank” specimen (no binder).

Calibration Process

• Step Two - Prepare two calibration samples at the design asphalt binder content.

• Burn the two samples as regular tests.

Note - after mixing if the specimens are allowed to cool, heat the material at binder compaction temperature for 30 minutes in a separate pan. Ignition oven baskets are not to be preheated before beginning this test.

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Aggregate Calibration (if degradation of aggregate occurred)

• Perform a gradation analysis on the residual aggregate.

• If the potential of lime needs to be determined, introduce water over the residual aggregate and add 2-4 drops of phenolphthalein alcohol indicator. Let rest 10 seconds and look for the potential presence of lime.

Aggregate Calibration (if degradation of aggregate occurred)

• Compare the gradations of the blank (unburned) specimen and the residual aggregate to evaluate the amount of aggregate breakdown.

• If the difference for any single sieve exceeds the allowable difference for that sieve as listed in Table 2, then aggregate correction factors for all sieves in that range, shall be applied to all acceptance gradation test results, prior to final rounding & reporting.

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Aggregate Calibration

Table 2

Permitted Sieving Difference

• Sizes larger than or equal to #8 ±5.0%

• Sizes larger than #200 and smaller than #8 ±3.0%

• Sizes #200 and smaller ± 0.5%


• Example: Difference between the burned & unburned averages is greater than 3.0% on the #30 sieve, then that correction factor would be applied to all the sieves larger than #200 and smaller than the #8 on all acceptance gradation test results.

• Note 9: For a mix containing RAP, add the percent passing gradation values of the RAP (from mix design) to the unburned sample percent passing to get accurate percent passing.

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• If degradation is suspected-(Section 12 CP-L 5120)

• Obtain a belt feed of the aggregate from the plant large enough for 4 specimens.

• Determine the gradation of two blank specimens.

• Mix 2 specimens at the design binder content, burn off the binder, perform gradation on residual aggregate.


• Compare the average gradation at each sieve size for the two sets of specimens.

• If the gradation for any single sieve exceeds the allowable difference for that sieve according to Table 2, then apply correction factors to all sieves in that range prior to any rounding or reporting.

• Calculate to the nearest 0.1%, except for the #200, it shall be to the nearest 0.01%.

• Report to nearest whole number, accept for the #200 sieve, to the nearest 0.1%.

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Calibration Process To Determine the Binder Correction Factor

• Determine the binder content for each sample by calculation.

• If the measured difference between the two burned samples is less than 0.15%, calculate the difference in binder content between the actual (optimum) and measured (mixed samples) binder contents for each sample.

• The calibration factor is the average of the differences between the actual and the measured asphalt contents for each sample.

Binder Calibration Process

If the measured difference between the two binder contents (burned samples) is greater than 0.15%:

◦ Mix up an additional two samples and repeat the procedure.

◦ Repeat procedure until the two results are within of each other 0.15%

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Using the Ignition Oven w/ RAP

• The ignition oven can be used to determine the asphalt content of mixes containing RAP.

• Prior to performing the mix calibration the percent binder (Pb) of the RAP must be determined by ignition with two RAP samples or the bitumen content from the mix design may be used.

• Chemical extractions for determining binder content on RAP are also used.

Using the Ignition Oven w/ RAP

• As with any materials, the sampling of RAP must be done carefully to result in samples that are representative of the larger mass of material.

• The gradation of the samples must be representative, gradation of specimen will affect the asphalt content results.

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Calibration Process w/ RAP

Weight of binder in RAP must be determined.

As per 9.2.2 the weight of RAP required is determined.

Then 9.2.3 has the formula for determining the weight of the binder in the RAP.

The next step is to determine the weight of new binder to add, to result in the desired percent of binder for specimen. Found in 9.2.4.

9.3 covers mixing up samples using two or more RAP stockpiles.

Table 1: Size of SpecimenNominal Maximum Sieve Size Specimen

Aggregate Size(mm) Weight

RANGE

4.75 #4 1200 - 1300

9.5 3/8” 1200 - 1300

12.5 ½” 1800 - 1900

19.0 ¾” 2200 - 2300

25.0 1 “ 3000 – 3100*

37.5 1.5 “ 4000 – 4100*

* Specimens shall be divided, each part tested, results averaged

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Test Procedure

• All production samples must have a moisture correction determination.

• As per 8.1, specimen may also be dried to 0.00% moisture prior to placement in the furnace.

• T110 or dry the HMA specimen to constant weight at 105 ± 5° C, [CP-43 at the specified binder compaction temperature for that mixture, as per Table 43-1 for a minimum of 3 hours]

• Preheat ignition oven per the manufacturer’s directions.

Test Specimens

Weigh and record weight of sample baskets on external scale.

Load test specimens into baskets 1 inch from sides.

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Test Specimens

• Record total weight of basket and specimen.

• Determine and record the test sample weight.

• Enter the sample weight into the furnace computer.

Test Procedure

• Zero the internal scale.

• Open the chamber door and place the baskets into the furnace.

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Test Procedure

Close chamber door and verify that the total weight (basket and material) equals the external recorded weight within ± 5 g.

Differences greater than 5 g, or a failure of the scale to stabilize, indicates the baskets are contacting the furnace wall.

Initiate the test by pressing the start button.

This will lock the chamber door and start the combustion blower.

Allow the test to continue until the stable light and audible stable indicator indicate the test is complete (the change in weight is less than 0.01% for three consecutive minutes).

Press the stop button to unlock the chamber door.

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Test Procedure

Open the chamber door.

Remove the baskets and allow the test specimen to cool sufficiently until it can safely handled.

If the internal scale is being used to determine the percent binder, remove the ticket and report the percent binder.

If the correction factor was not entered into the furnace, apply the correction factor before reporting the percent binder.

Test Procedure

If the external scale is being used to determine the percent binder;

Weigh the basket assembly containing the residual aggregate and record the weight.

The amount of time elapsed between the removal from the furnace and weighing on the external scale should be the same for correction factors and plant produced material (± 5 minutes).

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Test Procedure

• Determine the uncorrected asphalt binder content.

• Determine the corrected asphalt binder content by applying the Correction Factor and subtracting any moisture content.

Calculations

P P C Pb c o r r b unc o r r wF( ) ( )= + -

Where:

Pb(corr) = Asphalt binder content of field produced

specimens corrected for the aggregates and

asphalt binder sources

Pb(uncorr) = Uncorrected asphalt binder, determined by the

mass of the test specimen

CF = Calibration factor, percent by weight of the

HMA sample

Pw = Moisture content (percent water)

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Precision

Allowable Standard Deviation

• Single lab 0.20% RAP Mix

• Multi lab 0.40% RAP Mix

Questions ?

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STANDARD METHOD OF TEST FOR

DETERMINING MOISTURE (WATER) OR VOLATILE

DISTILLATES CONTENT OF ASPHALT PAVING

MIXTURES

CP 43

SCOPE:

THIS PROCEDURE COVERS TWO METHODS FOR THE QUANTITATIVE DETERMINATION OF MOISTURE IN ASPHALT PAVING MIXTURES.

THE PROCEDURES ARE INTENDED FOR THE DETERMINATION OF MOISTURE CONTENT OR VOLATILE FRACTION IN ASPHALT PAVING MIXTURES.

THE METHODS ARE INTENDED TO APPLY TO SAMPLES OF ASPHALT PAVING MIXTURES USED IN VERIFICATION AND QUALITY CONTROL FROM THE POINTS OF ACCEPTANCE DESIGNATED IN THE SCHEDULE FOR THE MINIMUM MATERIALS SAMPLING, TESTING AND INSPECTION.

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METHOD A APPARATUS;

◦ MICROWAVE OVEN - HAVING VARIABLE TIME AND

POWER CONTROLS.

◦ PYREX DISH (OR OTHER SUITABLE DISH) – CAPABLE

OF HOLDING THE ENTIRE TEST SPECIMEN BEING

TESTED.

◦ BALANCE – HAVING SUFFICIENT CAPACITY AND

SENSITIVITY TO 0.1G.

METHOD A –PROCEDURE FOR

CALIBRATING THE MICROWAVE

DETERMINE THE VARIABLE POWER SETTING:

SET THE VARIABLE POWER CONTROL TO

APPROXIMATELY 50% POWER.

PLACE 550 ± 50 ML OF WATER OF TAP WATER IN A

PYREX CONTAINER, RECORD THE TEMPERATURE OF THE

WATER (T1).

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METHOD A – PROCEDURE FOR CALIBRATING THE MICROWAVE

(CONTINUED)

SET THE MICROWAVE OVEN TIMER FOR FIVE MINUTES

AND HEAT 550 ML OF WATER. RECORD THE

TEMPERATURE (T2).

THE DIFFERENCE BETWEEN THE TEMPERATURE T1 AND

T2 SHOULD BE

75° F ± 10° (42° C ± 6°).

IF THE DIFFERENCE IS TOO LOW (OR HIGH) INCREASE (OR

DECREASE) THE VARIABLE POWER SETTING AND REPEAT

THE PROCESS.

METHOD A – MICROWAVE PROCEDURE

• PLACE A SPECIMEN IN A CLEAN, GLASS, DRY, TARRED CONTAINER AND OBTAIN THE SAMPLE MASS TO THE NEAREST 0.1G.

• THE SAMPLE WEIGHT SHOULD BE:

• 550 ± 50 G FOR GRADING S AND SX MIXES

• 2000 G FOR GRADING SG MIXES

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METHOD A - PROCEDURE

• DRY THE SPECIMEN IN THE MICROWAVE OVEN USING

THE VARIABLE POWER SETTING DETERMINED

PREVIOUSLY.

• CONTINUE TO DRY THE TEST SPECIMEN UNTIL THE

MASS OF THE SPECIMEN DOES NOT CHANGE AFTER

FURTHER HEATING CYCLES FOR A 5 MINUTE PERIOD.

• CARE SHOULD BE TAKEN TO AVOID OVERHEATING THE

SPECIMEN ~ AN INDICATION OF OVERHEATING IS BLUE

SMOKE.

CALCULATIONS

• DETERMINE THE PERCENT MOISTURE

TO THE NEAREST 0.01% AS FOLLOWS:

specimentestofmassweightDryBWhere

specimentestofmassweightWetAWhere

XA

BAMoisturePercent

)(

)(

100

=

=

−=

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METHOD B

• DRYING OVEN – THERMOSTATICALLY CONTROLLED FORCED

DRAFT OVEN.

• SPECIMEN CONTAINER – CAPABLE OF HOLDING THE ENTIRE

TEST SPECIMEN BEING TESTED.

• BALANCE – HAVING SUFFICIENT CAPACITY AND

SENSITIVITY TO 0.1G.

• MISCELLANEOUS – KNIVES, SPATULAS, SCOOPS, TOOLS,

ETC., AS REQUIRED IN APPLICABLE CP’S AND CP-L’S.

METHOD B PROCEDURE (OVEN)

PLACE THE SPECIMEN IN A CLEAN, DRY, TARRED CONTAINER AND WEIGH TO THE NEAREST 0.1G.

THE SAMPLE WEIGHT SHOULD NOT BE LESS THAN: 500 G FOR GRADING S AND SX MIXES 2000 G FOR GRADING SG MIXES

DRY THE SPECIMEN IN THE OVEN AT THE SPECIFIED

BINDER COMPACTION TEMPERATURE FOR THAT

MIXTURE (SEE TABLE 43-1), FOR A MINIMUM OF 3

HOURS. (TABLE 43 HAS BEEN UPDATED TO INCLUDE TEMPERATURES FOR PG 70-28)

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METHOD B PROCEDURE (OVEN)

REMOVE THE SPECIMEN AND IMMEDIATELY WEIGH TO THE NEAREST 0.1G.

PLACE THE SPECIMEN BACK INTO THE OVEN TO CONTINUE DRYING, CHECKING THE MASS OF THE SPECIMEN EVERY ½ HOUR, ±5 MINUTES.

THE SPECIMEN IS CONSIDERED DRY WHEN THE LOSS IN MASS IS LESS THAN OR EQUAL TO 0.00%

CALCULATIONS

• DETERMINE THE PERCENT

MOISTURE TO THE NEAREST

0.01% AS FOLLOWS:

specimentestofmassweightDryBWhere

specimentestofmassweightWetAWhere

XA

BAMoisturePercent

)(

)(

100

=

=

−=

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QUESTIONS?

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Standard Method of Testfor Asphalt Binder Content of

Asphalt Mixtures by the Nuclear Method

AASHTO T – 287

CDOT CP 85Asphalt Cement Content of Asphalt Mixtures by

the Nuclear Method

Purpose

• This method covers the determination of the asphalt cement (binder) mixture with a nuclear gauge.

• This method is a rapid determination of binder content (AC, binder).

• This procedure is sensitive to the type & gradation of aggregate, hydrated lime, percentage & source of binder.

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Purpose

• Measures total hydrogen in sample, including any moisture in the form of water.

• Moisture correction must be performed (CP 43).

• When using RAP in mix design, the RAP used in the calibration samples must be uniform in gradation, asphalt content and asphalt type.

• Samples of binder and aggregate for the calibration process shall be sampled and prepared per procedure.

• Field samples of mix for binder content determination shall be obtained and reduced to test specimen size as per CP 55.

• Prior to gauge operation:

• stationary location

• away from water

• away from other nuclear testing devices 33 feet (10 m)

Required:

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Required Apparatus

• Content gauge.

• 3 or more metal sample pans #9 clean & undamaged condition.

• Metal plate or plywood (or wooden survey stake).

• Steel straightedge approx. 18 inches in length.

• Balance, 33 lb (15 kg), readable to 0.1 g.

• Large mixing bowl, misc. hand tools.

• Ovens.

• Microwave oven (CP - 43) for moisture determination.

• Thermometer from 50-500 oF (10 to 300 oC).

Procedure Steps

• Background Count

• Sample preparation

• Aggregate count

• Calibration

• Moisture content

• Test

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Standardization (background)

• Top of gauge & surrounding area by 3 feet free of any hydrogenous type materials or personnel.

• Gauge empty and clean.

• Warm-up gauge a minimum of 20 minutes.

• Obtain background count for 16 minutes or a minimum 8 minutes.

• ± 1% from previous count.

• Statistical stability once per month.

Sample Preparation

• Obtain binder sample from job or supplier.

• Obtain aggregate samples from job or supplier.

• Obtain lime samples from job or supplier.

• Dry aggregates at 149 ± 8° C (300±15F) for a minimum of 3 hours or to constant weight.

• Heat binder to mixing temperature.

• Use job mix formula to blend aggregates in the correct proportion.

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Dry Aggregate Count

• Fill pan half full.

• Drop 1 inch four times to compact.

• Fill pan above rim.

• Repeat dropping 1 inch four times.

• Level off with straight edge using a sawing motion strike it off so it is level with the rim of the pan.

Dry Aggregate Count(continued)

• Record weight.

• Record temperature.

• Obtain and record count (16 minutes), repeat approximately once per week.

• Run to ensure that changes in the aggregate do not occur unnoticed.

• If a significant change is noted in this count ±0.5 %, a new calibration should be run.

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Mixing Samples

• Aggregates should be proportioned to the JMF.

• Correct amount of lime should also be mixed in with aggregates and sample hydrated before addition of binder.

• Mix samples with correct amount of properly graded binder.

Mixing Samples

• How much binder do you add? One formula is: Wb= (Ws x Pb)/(100-Pb)

• Where: Wb = Weight of binder, Ws = Weight of Stone, Pb= Percent of Binder.

• Assume 7000g of stone and 5% binder required.

• Example: Wb= (7000X5.0)/(100-5.0)

• Wb= 35000/95

• Wb= 368.4g

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• If RAP is being used, the percent binder in the

RAP must be known and the gradation of the RAP

used must uniformly match the RAP gradation

used in the mix design.

Use of RAP

• Mix a minimum of 3 calibration pans

(commonly more): one @ optimum, one @

+1%, one @ -1% or range (commonly at

0.5% increments) expected on the project.

• Fill pan half full

• Level sample

• Fill pan above rim

Calibration Curve Generation

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Calibration Continued

• If this is the first pan, the weight that fills the pan well becomes the base weight for all the other calibration pans & test samples during production.

• The corners should be filled and normally the optimum pan should be the first pan made during calibration to establish the base weight.


• The sample should then be compacted at a temperature between 250° and 300° F. Obtain and record temperature of first sample to establish the calibration temperature.

• All samples during calibration should then be within ± 10° F of this temperature.

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• Place sample in the gauge and obtain and record a 16 minute count.

• The result from the calibration pans should result in a correlation factor of 0.999 to 1.000 to be a valid calibration.

• If less than 0.999, new pans should be mixed and calibration run again.

• At conclusion, perform an additional background count. Variation greater than 1% from previous background count is unacceptable.

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Test Procedure

• Split out 2 samples, one for testing of %AC and one determining the %moisture from the field sample.

• Two methods can be used for determining the %moisture in CP 43: Method A Microwave or Method B Convection Oven.

• Fill pan half full.

• Level material in pan.

• Finish filling pan to base weight within 5 g.

Test Procedure (cont.)

• Check temperature prior to compaction (should be between 250° F and 300° F).

• Compact sample.

• Obtain 16 minute gauge count, record count & %Binder from gauge display.

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Test Procedure continued

• Correct the %Binder from gauge display by subtracting the % moisture (if it is determined that the sample contains moisture).

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Questions?????

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1

STANDARD METHOD OF TEST

FOR REDUCING FIELD

SAMPLES OF AGGREGATE TO TESTING SIZECDOT CP 32

PURPOSE OF SPLITTING

These methods provide for reducing large samples of aggregate to measure characteristics in a manner that the smaller test portion is most likely to be a representation of the larger sample, and thus of the total supply.

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Aggregates must be sampled in accordance with

Samples must be split properly to obtain representative test specimens.

METHODS

Method A - riffle type splitter

Method B – quartering

Method C –Selection by scoop (CDOT)Miniature stockpile method (AASHTO)

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RIFFLE APPARATUS

Riffle type splitter with variable size openings.

Hopper to retain sample or flat scoop (feeder pan) equal in length to the overall assembly of chutes.

Collection pans, minimum of two (2), equal in length to the overall assembly of chutes.

Splitter brush to clean chutes of adhering fines.

QUARTERING APPARATUS

6’ x 8’ quartering canvas or

Clean, hard, level surface (AASHTO)

Flat, square end shovel

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SCOOP & MINIATURE STOCKPILE APPARATUS (FINE AGGREGATE ONLY)

Large flat bottomed mixing pan (CDOT) or a clean, hard, level surface.

Small, flat, square end scoop.

BY RIFFLE SPLITTER

Riffle splitting is always preferable to hand quartering.

Proper size openings required.

Opening shall permit easy passage of the largest particles in the sample.

For variable splitters the openings should be 1.5 times the size of the largest particles

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METHOD A - RIFFLE SPLITTER

An even number of equal width chutes, but not less than 8 for coarse, or 12 for fine aggregates

The splitter shall be equipped with a hopper or straight-edged pan which has a width equal or slightly less the overall width of the assembly of chutes.

Sample at SSD or drier.

Two procedures to split sample:o Hoppero Scoop (feeder pan)

RIFFLE SPLITTER CONTROLFLOW HOPPER (CDOT)

Sample poured into the closed hopper from the sample container.

Use all material.

Uniformly distribute from edge to edge.

Open release handle and allow the sample to flow freely through the chutes.

The first split that is then reintroduced to the splitter assists in mixing the sample.

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HOPPER (CDOT)

Then remove both pans from the splitter.

Save material in one pan for other tests.

Pour half of the remaining pan into the hopper

Reverse ends of pan.

Pour the remaining sample into the hopper.

Riffle Splitter Control Flow Hopper (CDOT)

RIFFLE SPLITTER CONTROL FLOW HOPPER (CDOT)

Uniformly distribute material in hopper.

Open release handle and allow the sample to flow freely through the chutes.

Use alternate pans for further reduction.

Splitting is continued until the sample is reduced to the required specimen size.

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RIFFLE SPLITTER (AASHTO)

Splitting continued from one side until sample reduced to required specimen size

RIFFLE SPLITTER WITHOUT CONTROL HOPPER (CDOT)

Place entire sample in a large mixing pan and mix thoroughly.

Scoop the material from the pan with the feeder pan.

Uniformly distribute in feeder pan.

First, slowly pour half the sample from one side.

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RIFFLE SPLITTER WITHOUT CONTROL FLOW HOPPER (CDOT)

Pour the other half from the other side.

Continue until entire sample has been passed through the chutes.

Use alternate pans for further reduction to desired specimen size.


Sample deposited on clean, hard, level surface or canvas (6’ X 8’ canvas).

Mix material thoroughly by turning the entire sample over onto itself 3 times.

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Material shoveled into cone.

Cone flattened at apex into in circular layer.

Diameter equals approx. 4-8 times the thickness.


Uniform thickness.

Sample divided into two equal parts using a square shovel, pipe or stick under canvas if surface is uneven.

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Procedure repeated at 90 degrees.

Diagonal opposite quarters removed [include all fines].

Remaining two quarters re-mixed.

Procedure repeated

METHOD C – MINIATURE STOCKPILE(CDOT SCOOP)

Only for fine grained materials (minus 3/8 inches (9.5mm).

Sample should be damp.

Sample deposited into large pan and mixed 3 times.

Form into conical pile. Flatten pile (as in quartering).

Scoop to full depth of material.

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METHOD C – MINIATURE STOCKPILE

(CDOT SCOOP)

Mix and sample to minimize the loss of particles.

Portions selected from five (three) locations.

Portions combined for required weight.

METHODS FOR REDUCING SAMPLES WHEN USING A MECHANICAL SPLITTER CONTAINING

FREE MOISTURE

•Dry to at least SSD condition, using temps that do not exceed those specified for any tests.

•Then split to specified size.

OR

•Preliminary split with mechanical splitter having chute openings 1½” or more to reduce large sample to not less than 5000gr.

•Then dried as above and further reduced to desired size.

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QUESTIONS?

THANK YOU

23

1

Standard Method of Testfor Materials Finer Than 0.075-mm (No.

200) Sieve in Mineral Aggregates by Washing and the Sieve Analysis of Fine

and Coarse Aggregate.

– CDOT uses both:

CDOT CP 31

AASHTO T 11 / T 27

Summary

– The weight required (after drying) for this procedure, is based on the nominal maximum particle size.

– The -200 wash is performed to remove the finer material from the coarser particles for a more efficient result.

– The aggregate gradation is the distribution of particle sizes expressed as a percent of the total weight of the sample.

– The gradation is determined by passing the material through a series of sieves stacked with progressively smaller openings and weighing the material retained on each sieve

1

2

2

Apparatus Required

– Balance, with ample capacity and sensitivity (0.1 g)

– Sieves

– For the -200 wash, a nest of two sieves, the lower a No. 200 and the upper with openings in the range of No. 8 and No. 16

– For the Sieve Analysis, additional sieves, conforming to AASHTO M92 and ASTM E11

• Container, sufficient in size to contain the sample covered with water and to permit vigorous agitation without any loss of the sample or water

• Oven or hot plate.

Test Samples

– Aggregates must be

sampled in accordance

with CP 30.

– Aggregates must be

mixed and reduced to

test specimen size in

accordance with CP 32

3

4

3

CP 31 Sieve Analysis & Materials Finer than the No, 200

by washing

– AASHTO T 11 & T 27 (found in AASHTO portion of

handout) shall be used to determine the sieve analysis of

fine & coarse aggregates with the following exceptions:

– Table 31-1 still used for minimum sample mass.

– Moisture Correction process can still be used, according

to following procedure.

CP 31

–Split material into two approximately equal

samples.

–Dry one sample to constant mass in oven at 230°

F ± 9° oven or use a hotplate to determine %

moisture.

– Determine dry weight of second sample:

Wet weight/100 + %moisture X 100 = Corrected Dry Weight

5

6

4

Test Samples-Coarse AggregateTable 31-1

Aggregate Nominal Maximum Size square

openings,

Minimum Mass of Test Sample (AASHTO)

(kg)

Minimum Mass of Test Sample

Lb (kg)

3/8” 2 2.2 (1.0)

½” 4 3.3 (1.5)

¾” 11 4.4 (2.0)

1” 22 5.5 (2.5)

1.5” 33 11.0 (5.0)

2” 44 16.0 (7.5)

Procedure

Dry the sample to constant mass @ 110 ± 5° C (230 ± 9° F)and determine the mass of the test sample.

A hot plate is acceptable for drying if the aggregate temperature can be maintained above the boiling point of water.

Use moisture correction method.

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5

Procedure for the -200 wash– Place the sample into container and cover with

water.

– Add wetting agent if desired.

– Agitate the test sample with sufficient vigor to

separate the particles finer than the No. 200 sieve

and to bring the material into suspension.

Procedure, -200 wash (cont.)

– Immediately pour the wash water over the nested

sieves avoiding the decantation of coarser particles

of the sample.

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6

Procedure, -200 wash (continued)

– The entire sample may be placed into the upper sieve and

washed until the coarser fraction is clean, however all

water must pass through the No. 200 sieve.

– Add a second charge of water (no wetting agent).

– Agitate and decant.

– Repeat this operation until the wash water is clear.

Procedure, -200 wash (continued)

– Return all material retained on the sieves to the container.

– Dry the washed aggregate to a constant mass at 230 ± 9°F (110 ± 5° C)

– A hot plate is acceptable if the aggregate temperature can be maintained above the boiling point of water

– Cool to room temperature, determine and record the dry mass of the material.

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7

Before/After Sieve Weight Check

– Weigh & record weight of washed sample after drying prior to placing in the stack.

– Weigh & record weight of material from each sieve either individually or accumulatively.

– Final total weight should not differ by more than 0.3% of the original dry mass of the washed and dried sample.

( )Difference OriginalDryMass =100 03%.

Sieving Procedure

– Separate the specimen over a series

of suitable.

– Size sieves, including those required

by the specifications, manually or

mechanically.

– Do not overload sieves:

– 12 inch = Approx. 500g

– 8 inch = Approx. 200g

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8

Sieving Adequacy

– Annual calibration of shaker.

– Test using different material types.

– Hand shake each individual sieve for additional 1 minute.

– Pan on bottom and lid on top.

– Hold at slightly inclined angle and tap sharply with heel of hand.

– 25 taps at each of 6 locations around the sieve = 150 taps.

– Not more than 0.5% by weight of the total sample can pass.

Loss / original dry mass x 100= ≤ 0.5%

Procedure, Sieve (cont)

– Determine and record the mass of material retained

on each sieve to 0.1g

– individually

– cumulatively

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9

ProcedureCalculate the Moisture content

Calculate the original dry mass from the percent moisture

when using moisture correction methods.

Calculate percent retained to 0.1%

Calculate the percent passing and report to nearest whole

number except No. 200 to 0.1%

100 -% retained = % Passing

M/C = (Wet – Dry)/Dry x 100

Wet Weight ÷ (100 + %M) X 100 = Original Dry Weight

Sieve Weight ÷ Original Dry Weight X 100 = % Retained

Cumulative

Weights Individual

Weights

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Questions?

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20

Level B

Standard Method of Test for Asphalt Binder Content of AsphaltMixtures by the Nuclear Method

AASHTO Designation: T 287-141

SCOPE

This procedure covers the quantitative determination of the asphalt binder content of asphalt mixturesby testing a sample with a nuclear gauge that utilizes neutron-thermalization techniques.

The values expressed in SI units are to be regarded as the standard. The inch-pound equivalents of theSI units may be approximate.

Nuclear gauge operations and maintenance are not covered in detail. See the manufacturer's manualfor details.

This test method involves potentially hazardous materials, operations, and equipment. This methoddoes not purport to address all of the safety concerns associated with its use. All operators will betrained in radiation safety prior to operating nuclear gauges. Some agencies require the use of personalmonitoring devices such as a thermoluminescent dosimeter or film badge.

1.

1.1.

1.2.

1.3.

1.4.

REFERENCED DOCUMENTS

AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsR 66, Sampling Asphalt MaterialsR 76, Reducing Samples of Aggregate to Testing SizeT 2, Sampling of AggregatesT 11, Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by WashingT 27, Sieve Analysis of Fine and Coarse AggregatesT 110, Moisture or Volatile Distillates in Hot Mix Asphalt (HMA)T 168, Sampling Bituminous Paving MixturesT 255, Total Evaporable Moisture Content of Aggregate by DryingT 329, Moisture Content of Asphalt Mixtures by Oven Method

2.

2.1.

SUMMARY OF METHOD

This procedure can be used for rapid determination of the asphalt binder content of asphalt mixtures. Itis suitable for quality control and acceptance testing for construction and for research and developmentapplications. This procedure is useful in the determination of asphalt binder content only and does notprovide for gradation analysis.

This procedure determines the asphalt binder content of a test sample by comparing the measuredasphalt binder content with previously established calibration data. The asphalt binder content isexpressed as a percentage of the mass of the asphalt mixture.

Accurate results are dependent on proper calibration of the nuclear gauge to the material being testedas covered in Annex A. This procedure is sensitive to the type and gradation of the aggregate, liquid

3.

3.1.

3.2.

3.3.

Standard Method of Test for Asphalt Binder Content of Asphalt Mixture... http://hm.digital.transportation.org/HM/Part_II_Tests/Bituminous_Materi...

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anti-stripping additive or hydrated lime, and the percentage and source of the asphalt binder.

This procedure measures the total amount of hydrogen in a sample including the hydrogen present inthe form of water. Unless the test sample is totally free of water, the moisture content must bedetermined according to T 110 or T 329 and the percentage subtracted from the asphalt binder contentmeasured by the nuclear gauge. Alternatively, prior to testing, the sample may be dried to a constantmass in accordance with T 329, thereby nullifying the need for a moisture correction.

This procedure can be used with recycled asphalt pavement (RAP) incorporated into the asphaltmixture, provided that the RAP is of uniform gradation, asphalt binder content, and asphalt binder type.When RAP is used, the RAP should be mixed in the calibration samples in the same proportion that itwill be used on the construction project.

APPARATUS

Nuclear asphalt binder content gauge system consisting of:

Neutron Source—an encapsulated and sealed radioactive source;

Thermal neutron detectors;

Readout instrument—displaying, at a minimum, the percent of asphalt binder to the nearest 0.1percent; and

Three or more stainless-steel sample pans—conforming to the gauge requirements.

Mechanical mixer with a 10-kg (22-lb) capacity, capable of producing a completely mixed, well- coated,homogeneous asphalt mixture.

Sample containers such as paint cans or unwaxed, nonabsorbent cardboard boxes that can be closed toprevent contamination of the sample and are capable of withstanding the heating of the asphaltmixture to the mixing temperature.

Sample-quartering apparatus conforming to the requirements of R 76, Method B.

General-purpose balance or scale conforming to M 231, 20-kg (44-lb) capacity, readable to 0.1 g.

Drying Oven—capable of handling the required number of samples and sample sizes, of either of thefollowing types:

Forced-air convection oven capable of maintaining a temperature of 177 ± 3°C (350 ± 5°F).

Microwave oven, determined not to be detrimental to the aggregate, capable of maintaining atemperature of 177 ± 3°C (350 ± 5°F).

Leveling Plate—flat, rigid plate of metal [minimum thickness of 10 mm (0.4 in.)], Plexiglas [minimumthickness of 12.5 mm (0.5 in.)], or nonabsorptive plywood [minimum thickness of 19 mm (0.75 in.)],slightly larger than the sample pans.

Thermometer with a temperature range of 10 to 260°C (50 to 500°F).

Assorted pans, spoons, spatulas, and mixing bowls.

Radioactive materials information/calibration packet containing:

Daily standard count log;

Factory/laboratory calibration data sheet;

4.

4.1.

4.1.1.

4.1.2.

4.1.3.

4.1.4.

4.2.

4.3.

4.4.

4.5.

4.6.

4.6.1.

4.6.2.

4.7.

4.8.

4.9.

4.10.

4.10.1.

4.10.2.

4.10.3.


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Leak test certificate;

Shipper's declaration for dangerous goods;

Procedure memo for storing, transporting, and handling nuclear testing equipment; and

Other radioactive materials documentation conforming to local regulatory requirements.

PRECAUTIONS

The nuclear asphalt binder content gauge may be sensitive to outside influences and therefore:

Any other source of neutron radiation shall be kept at least 10 m (33 ft) from the apparatus during use;

The space within 1 m (3.3 ft) of the apparatus shall be kept free of hydrogenous material such aswater, plastics, asphalt binder, or asphalt mixtures during use;

All personnel shall be kept at least 1 m (3.3 ft) away from the gauge during testing; and

The gauge shall not be located within 10 m (33 ft) of any water supply tanks, fuel tanks, or other liquidcontainers subject to fluctuating liquid levels.

Moving the apparatus to a different location, even within the same laboratory, may cause a change inthe background radiation measurements. New background measurements, and possibly recalibration,will be necessary prior to use whenever background conditions have changed. See Sections 6 and 7 forinstructions concerning calibration and background measurements.

5.

5.1.

5.1.1.

5.1.2.

5.1.3.

5.1.4.

5.2.

CALIBRATION

Perform calibrations and cross-calibrations on asphalt mixtures tested in gauges, and transfercalibrations between gauges according to Annex A.

6.

6.1.

STANDARDIZATION

Obtain and record a background count in accordance with the manufacturer's procedure each day priorto taking test measurements or whenever the gauge has been moved or the conditions within 1 m (3.3ft) of the gauge have changed. The measurement time for the background count should be the sameas that used for the test measurements.

If the background count has not changed by more than 1 percent from the previous background count,then the apparatus shall be considered stable and acceptable for use. If the gauge has been moved orif the surrounding conditions have changed, additional background counts must be obtained until the 1percent standard is satisfied.

7.

7.1.

7.2.

PROCEDURE

Obtain a representative sample of asphalt mixture in accordance with T 168. If required, reduce thesample to the approximate test size by splitting or quartering according to R 76, Method B. It isrecommended that testing be performed while the asphalt mixture is still hot, and not reheated, ifpossible. If the asphalt mixture cools and reheating is necessary, heat it to the midpoint of the

8.

8.1.


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compaction temperature range for the asphalt binder used in the asphalt mixture.

Determine the mass of a clean gauge-sample pan, and tare the pan on the scale.

Place the asphalt mixture into the pan until it is about half full. Lightly tamp the asphalt mixture in thepan with a preheated spoon or spatula.

Place additional asphalt mixture into the pan until the required mass, as determined in Annex A, isreached within ±5 g.

Place the leveling plate on top of the asphalt mixture immediately after filling the pan. Compact thesample into the pan until it is level with the top of the pan by pressing down on the plate. Sight acrossthe top of the pan to ensure that the asphalt mixture does not protrude above the pan.

Record the mass of the asphalt mixture compacted into the pan. The mass shall be within ±5 g of thetarget mass.

Note 1—If the gauge does not have temperature-compensation capability, measure and record thetemperature of the compacted specimen. This temperature must be within ±5°C (9°F) of thecalibration-test-specimen temperature.

If the gauge has the ability to store multiple calibrations, activate the calibration for the particularasphalt mixture. Place the pan into the gauge, and perform a 4-min count.

Determine the uncorrected asphalt binder content by direct readout from the gauge, calibration graph,or formula supplied by the manufacturer. Record the uncorrected asphalt binder content from the 4-minreading to the nearest 0.1 percent.

Using a representative portion of the original sample or a portion of the material removed from thegauge pan, determine the moisture in the asphalt mixture according to T 110 or T 329, and record it tothe nearest 0.1 percent. Alternatively, prior to testing, the sample may be dried to a constant mass inaccordance with T 329, thereby nullifying the need for a moisture correction.

CALCULATION

When determined, subtract the moisture content from the uncorrected asphalt binder content. Recordthis value as the corrected asphalt binder content.

9.

9.1.

REPORT

Report the following information:

Make, model, and serial number of the nuclear asphalt binder content gauge;

Date and source of the calibration;

Date of the test;

Name and signature of the operator;

Background count for the day of the test;

Asphalt mixture identification;

Aggregate type and sources;

10.

10.1.

10.1.1.

10.1.2.

10.1.3.

10.1.4.

10.1.5.

10.1.6.

10.1.7.

10.1.8.


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Asphalt binder grade and source;

When used, source and amount of liquid anti-stripping additive or hydrated lime;

Calibration sample mass and temperature;

Test-sample mass and temperature if the gauge does not have temperature-compensation capability;

Gauge reading; and

Corrected asphalt binder content value to the nearest 0.1 percent.

KEYWORDS

Asphalt binder content; asphalt mixture; background count; calibration; cross-calibration; nucleardensity gauge.

11.

11.1.

ANNEXES(Mandatory Information)

SCOPE

This annex covers the preparation of samples for, and the calibration of, nuclear asphalt binder contentgauges. Job-mix formula (JMF) calibration and cross-calibration of master and field gauges areincluded.

A1.

A1.1.

SAMPLING

Obtain samples of aggregate according to T 2. Approximately 50 kg (110 lb) will be required for thecalibration specimens.

Note A1—The more accurately the ingredient materials (including liquid anti-stripping additive orhydrated lime) are prepared to match the JMF, the closer the calibration points will be to the productionasphalt mixture; and, therefore, the more accurate the results will be.

A2.

A2.1.

Obtain samples of asphalt binder according to R 66. Approximately 4 L (1 gal) will be required.A2.2.

AGGREGATE PREPARATION

When used, hydrate the appropriate amount of lime on the aggregate.

Dry the aggregate to a constant mass in accordance with T 255.

Separate the aggregate blend by dry-sieving on the specified sieves, including the minus 75-μm (No.200) material.

Calculate the required cumulative mass for each specified sieve using the following formula:

A3.

A3.1.

A3.2.

A3.3.

A3.4.


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(A3.1)

where:

X = the required, cumulative batch mass for each specified sieve (g);

T = the initial, total aggregate mass (g); and

P = the percent passing for each specified sieve according to the JMF.

Perform an aggregate dust correction as follows:

Prepare a washed-gradation sample from the masses calculated in Section A3.4.

Perform a washed gradation according to T 27 and T 11.

Calculate the corrected batch mass for each specified sieve for the calibration points using the followingformula:

(A3.2)

where:

Zn = the adjusted, cumulative batch mass for any sieve size, n (g);

X = the prewash, cumulative batch mass for each specified sieve (g); and

Y = the post-wash, cumulative batch mass for each specified sieve (g).

Blend the aggregate together at the proper proportion to match the JMF using the masses calculated inSection A3.5.3.

ASPHALT BINDER PREPARATION

Heat a minimum of 2 L (0.5 gal) of asphalt binder to the midpoint of the mixing temperature range in acovered container(s). When used, add the appropriate amount of liquid anti-stripping additive to theasphalt binder. Use the asphalt binder as soon as it reaches the midpoint of the mixing temperaturerange. If this operation is not possible, maintain the asphalt binder at this temperature for no morethan 4 h. Do not cool and reheat the asphalt binder.

Method A—Asphalt binder percent by mass of the asphalt mixture.

Calculate the mass of asphalt binder for each calibration point as follows:

A4.

A4.1.

A4.2.

A4.2.1.


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(A4.1)

where:

B = the mass of the asphalt binder to the nearest 0.1 g;

E = the mass of the asphalt mixture (g); and

Pbm = the percent of asphalt binder by total mass of the asphalt mixture, expressed as adecimal.

Asphalt binder contents will be chosen at the optimum asphalt binder content and at increments of±0.8 percent from the optimum asphalt binder content. The minimum four samples are at 0.8 percentbelow optimum, at optimum, at 0.8 percent above optimum, and at 1.6 percent above optimum.

Calculate the mass of aggregate required for each calibration point as follows:

(A4.2)

where:

A = the mass of the aggregate to the nearest 0.1 g.

Method B—Asphalt binder percent by mass of the aggregate.

Calculate the mass of aggregate for each calibration point as follows:

(A4.3)

where:

Pba = the percent of asphalt binder by mass of the aggregate, expressed as a decimal.

Asphalt binder contents will be chosen at the optimum asphalt binder content and at increments of±0.8 percent from the optimum asphalt binder content. The minimum four samples are at 0.8 percentbelow optimum, at optimum, at 0.8 percent above optimum, and at 1.6 percent above optimum.

Calculate the mass of asphalt binder required for each calibration point as follows:

(A4.4)

PREPARATION FOR SPECIMENSA5.A5.1.


7 of 10 8/8/17, 11:11 AM

The aggregate and asphalt binder materials must be heated to the midpoint of the mixing temperaturerange for that asphalt binder. Once these materials have stabilized at that temperature, proceed withthe following steps:

Determine the mass of the heated mixing bowl to the nearest 0.1 g.

Place a heated aggregate specimen, of the required mass to the nearest 0.1 g, in the mixing bowl.

Form a crater in the aggregate large enough to hold the required mass of asphalt binder.

Place the mixing bowl on the scale. Add the required, preheated asphalt binder mass, to the nearest 0.1g, into the aggregate crater.

Mechanically mix the aggregate and asphalt binder rapidly for a minimum of 2 min until they arethoroughly blended. Check the bottom and sides of the bowl for unmixed aggregate and asphalt binder.If necessary, remix the sample by hand until it is thoroughly mixed.

Note A2—Hand-mixing is not recommended. However, mixing may be performed by hand in a largebowl. In this case, the mixing time shall be a minimum of 5 min, but it may be longer to ensurethorough mixing.

Remove the asphalt mixture from the bowl, and determine the mass of the empty bowl to ensure thatall material has been removed. The mass of the bowl shall be within ±5 g of the mass determined inSection A5.2. If it is not, scrape the bowl with a spatula, and deposit the excess into the sample, untilthe mass of the bowl is within the tolerance.

TARGET MASS DETERMINATION

Note A3—To find an approximate starting mass, place the dry aggregate in a gauge-sample pan. Fillthe pan half full; then drop it from a height of 25 mm (1 in.). Fill the pan just over full, and strike it offeven with the top. Determine this mass, and add 10 percent to obtain an approximate starting mass.

Mix the preheated aggregate and asphalt binder according to Section A5.



Place the remaining asphalt mixture into the pan so that the asphalt mixture is mounded about 13 mm(0.5 in.) above the top of the pan.


Determine and record the mass of the asphalt mixture compacted into the pan. This value is the targetmass. The subsequent calibration and sample specimens must be within ±5 g of this mass.

A6.

An initial, or “butter” batch is prepared to determine the mass to be used for the calibration samplesusing an asphalt binder/aggregate blend approximating the real batches. Based on experience withaggregate specific gravity and gradation, the target mass will be from 6000 to 9000 g.

A6.1.

A6.2.

A6.3.

A6.4.

A6.5.

A6.6.

A6.7.

CALIBRATION (GENERAL)A7.A7.1.


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The type of aggregate, source and grade of asphalt binder, liquid anti-stripping additive or hydratedlime, and asphalt mixture gradation will influence the test results obtained using this procedure.Accordingly, a calibration curve must be developed for each combination of these factors.

The calibration curve must cover the range of expected values found in field samples. The limits for thecalibration curve must consider the allowable range of asphalt binder content plus the allowableaggregate moisture (which reads as asphalt binder in the gauge). At a minimum, use 0.8 below,optimum, 0.8 above, and 1.6 percent above the optimum asphalt binder content when making thecalibration-curve pans.

JMF CALIBRATION

Prepare four aggregate samples using the target mass determined in Section A6.7. Place them inseparate pans designed for, and capable of, transferring the dry aggregate into a mixing bowl with aminimum loss of aggregate. Place them in an oven set at the midpoint of the mixing temperature rangefor the asphalt binder to be used.

Determine the mass of the aggregate and asphalt binder for each calibration sample according toSections A3 and A4, respectively.

Mix the preheated aggregate and asphalt binder according to Section A5.



Place the remaining asphalt mixture into the pan so that the asphalt mixture is mounded about 13 mm(0.5 in.) above the top of the pan.


Determine and record the mass of the asphalt mixture compacted into the pan. The mass shall bewithin ±5 g of the target mass determined in Section A6.7.

Place the pan into the gauge, and proceed in accordance with the manufacturer's instructions for theoperation of the equipment and the sequence of operations.

Note A4—Do not forget to perform a background count according to the manufacturer's instructions.

Repeat Sections A8.2 through A8.9 for the other calibration samples.

A8.

A8.1.

A8.2.

A8.3.

A8.4.

A8.5.

A8.6.

A8.7.

A8.8.

A8.9.

A8.10.

PRESENTATION OF CALIBRATION DATA

For gauges that generate the calibration internally to the gauge:

Print or otherwise record the formula coefficients, the coefficient of fit, and the calculated percentdifference for each calibration point. If the coefficient of fit is less than 0.998 for a dense-gradedasphalt mixture or 0.995 for an open-graded asphalt mixture, or any calibration point has a calculatedpercent difference greater than 0.09 percent, the calibration is not acceptable and must be performedagain.

Store the acceptable calibration in the gauge's memory, using the JMF and an easily recognizable

A9.

A9.1.

A9.1.1.

A9.1.2.


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1 Minor editorial revisions have been made at the discretion of the authors responsible for standards on Asphalt–Aggregate Mixtures (technical section 2c).

calibration number, according to the manufacturer's instructions.

For gauges that do not generate the calibration internally to the gauge:

Prepare a calibration curve by plotting the gauge readings for the calibration samples versus asphaltbinder content on linear graph paper, choosing convenient scale factors for the gauge readings andasphalt binder content.

CROSS-CALIBRATION (WHEN APPLICABLE)

The formula coefficients are entered into the field gauge in the transfer mode during the cross-calibration process. The new formula coefficients, when printed, will not resemble the values enteredbecause they will change based on this relationship. For more detailed information on the formulacoefficients, refer to the manufacturer's instructions. If required, a “straight” calibration may beperformed and used instead of the transfer program. This option requires that the sample pans used forthe calibration be tested in another gauge if the testing must be verified by the agency.

Note A5—Some agencies cross-calibrate gauges. This process creates a relationship between the fieldgauge and the gauge used in the JMF calibration, allowing the testing of production asphalt mixturewithout the need to perform calibrations in the field. When several gauges are cross-calibrated, theasphalt mixture calibrations may be transferred to each gauge.

Note A6—To seal the pan, cut a piece of tin the size of the top of the sample pan. Seal the edges ofthe pan and tin lid with an epoxy. This process will seal any moisture out.

Test each of the six sealed calibration samples in the field gauge while it is in the cross-calibrationmode. For each calibration sample, input the data obtained from the master gauge into the field gauge.The master and field gauges are now cross-calibrated.

Note A7—Annually, or whenever a field gauge differs from the master gauge, a new cross-calibrationmust be performed using the sealed pans originally produced for the gauge standardization. These sixpans must be checked monthly in the master gauge to verify that the counts have not changedsubstantially.

A10.

A10.1.

Prepare six calibration samples using a locally available, agency-approved aggregate, with asphaltbinder contents between 3 and 8 percent at 1-percent increments. Mix the samples so that each pan ofasphalt mixture equals the target mass ±5 g as determined for the aggregate. Test each sample in themaster gauge using 16-min counts in the normal calibration mode. After all samples are tested, thegauge will automatically calculate a coefficient of fit. The coefficient of fit must be at least 0.999. Sealeach pan to prevent a change in hydrogen content, and repeat the procedure. Sealed pans must meetthe same criteria as above.

A10.2.

A10.3.


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Standard Method of Test for Bulk Specific Gravity ( ) ofCompacted Hot Mix Asphalt (HMA) Using Saturated Surface-Dry

SpecimensAASHTO Designation: T 166-16

Release: Group 3 (August 2016)

SCOPE

This method of test covers the determination of bulk specific gravity (Gmb) of specimens of compactedhot mix asphalt (HMA).

This method should not be used with samples that contain open or interconnecting voids or absorbmore than 2.0 percent of water by volume, as determined in Sections 7.2 or 10.2 herein. If the samplecontains open or interconnecting voids or absorbs more than 2.0 percent of water by volume, then T275 or T 331 should be used.

The bulk specific gravity (Gmb) of the compacted HMA may be used in calculating the unit mass of themixture.

Note 1—The values for bulk specific gravity (Gmb) obtained from T 275 or T 331 may differ. Careshould be exercised when comparing test results from T 275 and T 331.

The values stated in SI units are to be regarded as the standard.

This standard may involve hazardous materials, operations, and equipment. This standard does notpurport to address all the safety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and health practices and determine the applicabilityof regulatory limitations prior to use.

1.

1.1.

1.2.

1.3.

1.4.

1.5.


AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsT 275, Bulk Specific Gravity (Gmb) of Compacted Hot Mix Asphalt (HMA) Using Paraffin-CoatedSpecimensT 331, Bulk Specific Gravity (Gmb) and Density of Compacted Hot Mix Asphalt (HMA) Using AutomaticVacuum Sealing Method

ASTM Standards:

C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods forConstruction MaterialsD7227/D7227M, Standard Practice for Rapid Drying of Compacted Asphalt Specimens Using VacuumDrying ApparatusE1, Standard Specification for ASTM Liquid-in-Glass Thermometers

2.

2.1.

2.2.

Standard Method of Test for Bulk Specific Gravity (Gmb) of Compacte... http://hm.digital.transportation.org/HM/Part_II_Tests/Bituminous_Materi...

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TERMINOLOGY

Definitions:

constant mass—shall be defined as the mass at which further drying does not alter the mass by morethan 0.05 percent when weighed at 2-h intervals when using oven drying, or by more than 0.05 percentwhen weighed after at least two drying cycles of the vacuum-drying apparatus required in ASTMD7227/D7227M.

3.

3.1.

bulk specific gravity (of solids) (Gmb), as determined by this test method—the ratio of a given mass ofmaterial at 25°C (77°F) to the mass of an equal volume of water at the same temperature.

3.1.1.

3.1.2.

TEST SPECIMENS

Test specimens may be either laboratory-compacted HMA or sampled from HMA pavements.

Size of Specimens—It is recommended that: (1) the diameter of cylindrically compacted or coredspecimens, or the length of the sides of sawed specimens, be at least equal to four times the maximumsize of the aggregate; and (2) the thickness of specimens be at least one and one-half times themaximum size of the aggregate.

Specimens shall be taken from pavements with a core drill, diamond or carborundum saw, or by othersuitable means.

Care shall be taken to avoid distortion, bending, or cracking of specimens during and after the removalfrom the pavement or mold. Specimens shall be stored in a safe, cool place.

Specimens shall be free from foreign materials such as seal coat, tack coat, foundation material, soil,paper, or foil.

If desired, specimens may be separated from other pavement layers by sawing or other suitable means.Care should be exercised to ensure sawing does not damage the specimens.

4.

4.1.

4.2.

4.3.

4.4.

4.5.

4.6.

METHOD A

APPARATUS

Weighing Device—The weighing device shall have sufficient capacity, be readable to 0.1 percent of thesample mass or better, and conform to the requirements of M 231. The weighing device shall beequipped with a suitable suspension apparatus and holder to permit weighing the specimen whilesuspended from the center of the scale pan of the weighing device.

Suspension Apparatus—The wire suspending the container shall be the smallest practical size tominimize any possible effects of a variable immersed length. The suspension apparatus shall beconstructed to enable the container to be immersed to a depth sufficient to cover it and the test sampleduring weighing. Care should be exercised to ensure no trapped air bubbles exist under the specimen.

Water Bath—For immersing the specimen in water while suspended under the weighing device,equipped with an overflow outlet for maintaining a constant water level.

5.

5.1.

5.2.

5.3.


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PROCEDURE

Dry the specimen to a constant mass at a temperature of 52 ± 3°C (125 ± 5°F). Samples saturatedwith water shall initially be dried overnight and then weighed at 2-h drying intervals. Recentlycompacted laboratory samples, which have not been exposed to moisture, do not require drying. As analternative to oven drying to constant mass, drying the sample according to ASTM D7227/D7227M maybe used. When using ASTM D7227/D7227M to achieve constant mass, perform the drying procedure atleast twice, with a mass determination after each drying cycle.

Cool the specimen to room temperature at 25 ± 5°C (77 ± 9°F), and record the dry mass as A (Note2). Immerse each specimen in the water bath at 25 ± 1°C (77 ± 1.8°F) for 4 ± 1 min, and record theimmersed mass as C. Remove the specimen from the water bath; damp-dry the specimen by blotting itwith a damp towel, and determine the surface-dry mass as B as quickly as possible (the entireoperation is not to exceed 15 s). Any water that seeps from the specimen during the weighingoperation is considered part of the saturated specimen. Each specimen shall be immersed and weighedindividually.

Note 2—If desired, the sequence of testing operations may be changed to expedite the test results.For example, first the immersed mass C can be taken, then the surface-dry mass B, and finally the drymass A.

Note 3—Terry cloth has been found to work well for an absorbent cloth. Damp is considered to bewhen no water can be wrung from the towel.

6.

6.1.

6.2.

CALCULATION

Calculate the bulk specific gravity (Gmb) of the specimen as follows:

(1)

where:

A = mass of the specimen in air, g;

B = mass of the surface-dry specimen in air, g; and

C = mass of the specimen in water, g.

Calculate the percent of water absorbed by the specimen (on a volume basis) as follows:

(2)

If the percent of water absorbed by the specimen as calculated in Section 7.2 exceeds 2.0 percent, useeither T 275 or T 331 to determine the bulk specific gravity (Gmb).

7.

7.1.

7.2.

7.3.


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METHOD B

APPARATUS

Weighing Device—The weighing device shall have sufficient capacity, be readable to 0.1 percent of thesample mass or better, and conform to the requirements of M 231.

Water Bath—For immersing the specimen in water.

Thermometer—ASTM 17C (17F) as provided in ASTM E1, having a range of 19 to 27°C (66 to 80°F),graduated in 0.1°C (0.2°F) subdivisions.

Volumeter1—Calibrated to 1200 mL, or an appropriate capacity depending on the size of the testsample. The volumeter shall have a tapered lid with a capillary bore.

8.

8.1.

8.2.

8.3.

8.4.

PROCEDURE

Dry the specimen to a constant mass at a temperature of 52 ± 3°C (125 ± 5°F). Samples saturatedwith water shall initially be dried overnight and then weighed at 2-h drying intervals. Recentlycompacted laboratory samples, which have not been exposed to moisture, do not require drying. As analternative to oven drying to constant mass, drying using ASTM D7227/D7227M may be used. Whenusing ASTM D7227/D7227M to determine the constant mass, follow the drying procedure at least twice,with a mass determination after each drying procedure.

Cool the specimen to room temperature at 25 ± 5°C (77 ± 9°F), and record the dry mass as A (Note2). Immerse the specimen in the water bath at 25 ± 1°C (77 ± 1.8°F), and let it saturate for at least 10min. At the end of the 10-min period, fill a calibrated volumeter with distilled water at 25 ± 1°C (77 ±1.8°F), and weigh the volumeter. Designate this mass as D. Remove the saturated specimen from thewater bath and damp-dry the specimen by blotting with a damp towel (Note 3) as quickly as possible(not to exceed 5 s). Weigh the specimen, and record the surface-dry mass as B. Any water that seepsfrom the specimen during the weighing operation is considered part of the saturated specimen.

Place the specimen into the volumeter, and let it stand for at least 60 s. Bring the temperature of thewater to 25 ± 1°C (77 ± 1.8°F), and cover the volumeter, making certain that some water escapesthrough the capillary bore of the tapered lid. Wipe the outside of the volumeter dry with a dry,absorbent cloth, and weigh the volumeter and its contents (Note 4). Record this weight as E.

Note 4—If desired, the sequence of testing operations can be changed to expedite the test results. Forexample, first the mass of the saturated, damp-dry specimen B can be taken. Then the volumetercontaining the saturated specimen and water E can be weighed. The dry mass of the specimen A canbe determined last.

Note 5—Method B is not acceptable for specimens that have more than 6 percent air voids.

9.

9.1.

9.2.

9.3.

CALCULATIONS

Calculate the bulk specific gravity (Gmb) of the specimen as follows:

10.

10.1.


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(3)

where:

A = mass of the dry specimen, g;

B = mass of the surface-dry specimen, g;

D = mass of the volumeter filled with water at 25 ± 1°C (77 ± 1.8°F), g; and

E = mass of the volumeter filled with the specimen and water at 25 ± 1°C (77 ± 1.8°F), g.

Calculate the percent of water absorbed by the specimen (on a volume basis) as follows:

(4)

If the percent of water absorbed by the specimen as calculated in Section 10.2 exceeds 2.0 percent,use either T 275 or T 331 to determine the bulk specific gravity (Gmb).

METHOD C (RAPID TEST)

PROCEDURE

This procedure can be used for testing specimens that are not required to be saved and that contain asubstantial amount of moisture. Specimens obtained by coring or sawing can be tested the same day bythis method.

The testing procedure shall be the same as given in Section 6 or 9 except for the sequence ofoperations. The dry mass A of the specimen is determined last as follows:

11.

11.1.

11.2.

11.2.1. Place the specimen in a large, flat-bottom drying pan of known mass. Place the pan and specimen in anoven at 110 ± 5°C (230 ± 9°F). Leave the specimen in the oven until it can be easily separated to thepoint where the particles of the fine aggregate-asphalt portion are not larger than 6.3 mm (1/4 in.).Place the separated specimen in an oven at 110 ± 5°C (230 ± 9°F), and dry to a constant mass.

11.2.2. Cool the pan and specimen to room temperature at 25 ± 5°C (77 ± 9°F). Determine the mass of thepan and specimen, subtract the mass of the pan, and record as the dry mass, A.

CALCULATIONS

Calculate the bulk specific gravity (Gmb) as given in Section 7.1 or 10.1.

12.

12.1.


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1 Suitable aluminum volumeters of different sizes are available from Pine Instrument Co., 101 Industrial Drive, GroveCity, PA 16127; and Rainhart Co., 604 Williams St., Austin, TX 78765.

REPORT

The report shall include the following:

The method used (A, B, or C).

Bulk specific gravity (Gmb) reported to the nearest thousandth.

Absorption reported to the nearest hundredth.

13.

13.1.

13.1.1.

13.1.2.

13.1.3.

PRECISION

Table 1—Precision Estimates for T 166

14.

KEYWORDS

Asphalt mixture; bulk specific gravity; hot mix asphalt; saturated surface-dry; volumeter.

15.

15.1.


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Standard Method of Test for Determining the Asphalt Binder Contentof Hot Mix Asphalt (HMA) by the Ignition Method

AASHTO Designation: T 308-16


SCOPE

This test method covers the determination of asphalt binder content of hot mix asphalt (HMA) byignition at temperatures that reach the flashpoint of the binder in a furnace. The means of specimenheating may be the convection method or the direct infrared (IR) irradiation method. The aggregateremaining after burning can be used for sieve analysis using T 30.


This standard may involve hazardous materials, operations, and equipment. This standard does notpurport to address all of the safety concerns associated with its use. It is the responsibility of the userof this standard to consult and establish appropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.

1.

1.1.

1.2.

1.3.


AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsR 47, Reducing Samples of Hot Mix Asphalt (HMA) to Testing SizeR 66, Sampling Asphalt MaterialsR 76, Reducing Samples of Aggregate to Testing SizeT 2, Sampling of AggregatesT 30, Mechanical Analysis of Extracted AggregateT 168, Sampling Bituminous Paving MixturesT 329, Moisture Content of Asphalt Mixtures by Oven Method

ASTM Standard:

C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods forConstruction Materials

Other Documents:

Manufacturer's Instruction ManualNCHRP Final Report, NCHRP Project No. 9-26, Phase 3

2.

2.1.

2.2.

2.3.

SUMMARY OF TEST METHOD

The asphalt binder in the HMA is ignited using the furnace equipment applicable to the particularmethod. This procedure covers two methods. Method A requires an ignition furnace with an internalbalance. Method B requires an ignition furnace with an external balance.

3.

3.1.

3.2.

Standard Method of Test for Determining the Asphalt Binder Content of... http://hm.digital.transportation.org/HM/Part_II_Tests/Bituminous_Materi...

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The asphalt binder content is calculated as the difference between the initial mass of the HMA and themass of the residual aggregate, with adjustments for an asphalt binder correction factor and themoisture content. The asphalt binder content is expressed as a mass percent of the moisture-freemixture. This method may be affected by the type of aggregate in the mixture. Accordingly, to optimizeaccuracy, correction factors for asphalt binder and aggregate will be established by testing a set ofcorrection factor specimens for each type of HMA. Correction factors must be determined before anyacceptance testing is performed.

SIGNIFICANCE AND USE

This method can be used for quantitative determinations of asphalt binder content and gradation inHMA and pavement specimens for quality control, specification acceptance, and mixture evaluationstudies. This method does not require the use of solvents. Aggregate obtained by this test method maybe used for gradation analysis according to T 30.

4.

4.1.

APPARATUS

For Method A, the furnace shall also have an internal balance thermally isolated from the furnacechamber and accurate to 0.1 g. The balance shall be capable of weighing a 3500-g specimen in additionto the specimen baskets. A data collection system will be included so that the mass can beautomatically determined and displayed during the test. The furnace shall have a built-in computerprogram to calculate the change in mass of the specimen baskets and provide for the input of acorrection factor for aggregate loss. The furnace shall provide a printed ticket with the initial specimenmass, specimen mass loss, temperature compensation, correction factor, corrected asphalt bindercontent (percent), test time, and test temperature. The furnace shall provide an audible alarm andindicator light when the specimen mass loss does not exceed 0.01 percent of the total specimen massfor 3 consecutive min. The furnace shall also allow the operator to change the ending mass losspercentage to 0.02 percent.

Specimen Basket Assembly—Consisting of specimen basket(s), catch pan, and an assembly guard tosecure the specimen basket(s) to the catch pan.

Specimen Basket(s)—Of appropriate size to allow the specimens to be thinly spread and allow air toflow through and around the specimen particles. Sets with two or more baskets shall be nested. Thespecimen shall be completely enclosed with screen mesh, perforated stainless steel plate, or othersuitable material.

Note 1—Screen mesh or other suitable material with maximum and minimum openings of 2.36 mm(No. 8) and 0.600 mm (No. 30), respectively, has been found to perform well.

Catch Pan—Of sufficient size to hold the specimen basket(s) so that aggregate particles and meltingasphalt binder falling through the screen are caught.

Oven—Capable of maintaining 110 ± 5°C (230 ± 9°F).

5.

Ignition Furnace—A forced-air ignition furnace that heats the specimens by either the convection ordirect IR irradiation method. The convection-type furnace must be capable of maintaining atemperature of 538 ± 5°C (1000 ± 9°F). The furnace chamber dimensions shall be adequate toaccommodate a specimen size of 3500 g. The furnace door shall be equipped so that the door cannotbe opened during the ignition test. A method for reducing furnace emissions shall be provided. Thefurnace shall be vented into a hood or to the outside and, when set up properly, shall have nonoticeable odors escaping into the laboratory. The furnace shall have a fan capable of pulling airthrough the furnace to expedite the test and reduce the escape of smoke into the laboratory.

5.1.

5.1.1.

5.2.

5.2.1.

5.2.2.

5.3.


2 of 9 8/8/17, 11:12 AM

Balance—Of sufficient capacity and conforming to the requirements of M 231, Class G 2.

Safety Equipment—Safety glasses or face shield, dust mask, high-temperature gloves, long-sleevedjacket, a heat-resistant surface capable of withstanding 650°C (1202°F), and a protective cage capableof surrounding the specimen baskets during the cooling period.

Miscellaneous Equipment—A pan larger than the specimen basket(s) for transferring the specimen afterignition, spatulas, bowls, and wire brushes.

SAMPLING

Obtain samples of freshly produced HMA in accordance with T 168.

The specimen shall be the end result of reducing a larger sample in accordance with R 47.

If the mixture is not sufficiently soft to separate with a spatula or trowel, place it in a large, flat pan inan oven at 110 ± 5°C (230 ± 9°F) until it is workable. Do not leave the specimen in the oven for anextended period of time. Excessive heating may cause detrimental effects such as asphalt draindown oroxidation.

The size of the test specimen shall be governed by the nominal-maximum aggregate size of the HMAand shall conform to the mass requirement shown in Table 1. When the mass of the specimen exceedsthe capacity of the equipment used, the specimen may be divided into suitable increments, tested, andthe results appropriately combined for calculation of the asphalt binder content (using a weightedaverage). Specimen sizes shall not be more than 500 g greater than the minimum recommendedspecimen mass.

Note 2—Large specimens of fine mixes tend to result in incomplete ignition of asphalt binder.

Table 1—Mass Requirements

6.

6.1.

6.2.

6.3.

6.4.

TEST METHOD A—INTERNAL BALANCE

TEST PROCEDURES7.


3 of 9 8/8/17, 11:12 AM

Test Initiation:

For the direct IR irradiation-type furnace, use the same burn profile as used during the correction factordetermination.

Oven dry the HMA specimen to a constant mass at a temperature of 110 ± 5°C (230 ± 9°F), ordetermine the moisture content of a companion specimen according to T 329.

Enter into the ignition furnace, or manually record, the asphalt binder correction factor for the specificmix to be tested, as determined in the Annex.

Determine and record the mass of the specimen basket assembly to the nearest 0.1 g.

Prepare the specimen as described in Section 6. Place the specimen basket(s) in the catch pan. Evenlydistribute the specimen in the basket(s), taking care to keep the material away from the edges of thebasket. Use a spatula or trowel to level the specimen.

Determine and record the total mass of the specimen and specimen basket assembly at roomtemperature to the nearest 0.1 g. Calculate and record the initial mass of the specimen, Mi (total massminus the mass of the specimen basket assembly).

Input the initial mass of the specimen, Mi, in whole grams into the ignition furnace controller. Verify thatthe correct mass has been entered.

Open the chamber door and place the specimen basket assembly in the furnace, carefully positioningthe specimen basket assembly so it is not in contact with the furnace walls. Close the chamber doorand verify that the specimen mass (including the basket assembly) displayed on the furnace scaleequals the total mass recorded in Section 7.6 within ±5 g. Differences greater than 5 g or failure of thefurnace scale to stabilize may indicate that the specimen basket assembly is contacting the furnacewall.

Note 3—Due to the extreme heat of the furnace, the operator should wear safety equipment—high-temperature gloves, face shield, and fire-retardant shop coat—when opening the door to load or unloadthe specimen.

Initiate the test by pressing the start/stop button. This operation will lock the specimen chamber andstart the combustion blower.

Note 4—The furnace temperature will drop below the set point when the door is opened but willrecover with the door closed and when ignition occurs. Specimen ignition typically increases thetemperature well above the set point, depending on the specimen size and asphalt binder content.

Allow the test to continue until the stable light and audible stable indicator indicate the test is complete(the change in mass does not exceed 0.01 percent for 3 consecutive min). Press the start/stop button.This operation will unlock the specimen chamber and cause the printer to print out the test results.

Note 5—An ending mass loss percentage of 0.02 may be substituted when the aggregate exhibits anexcessive amount of loss during ignition testing. The precision and bias statement was developed using0.01 percent. Both precision and accuracy may be adversely affected by using 0.02 percent.

Open the chamber door, remove the specimen basket assembly, and place it on a cooling plate orblock. Place the protective cage over the specimen basket assembly, and allow it to cool to roomtemperature (approximately 30 min).

Determine and record the total mass of the specimen and specimen basket assembly after ignition to

For the convection-type furnace, preheat the ignition furnace to 538± 5°C (1000± 9°F) or to thetemperature determined by the correction factor process in the Annex. Manually record the furnacetemperature (set point) prior to the initiation of the test if the furnace does not record automatically.

7.1.1.


4 of 9 8/8/17, 11:12 AM

the nearest 0.1 g. Calculate and record the final mass of the specimen, Mf (total mass minus the massof the specimen basket assembly).

Use the corrected asphalt binder content (percent) from the printed ticket. If this value is not corrected,subtract the asphalt binder correction factor. If a moisture content has been determined per T 329,subtract the percent moisture from the asphalt binder content on the printed ticket, and report theresultant value as the corrected asphalt binder content (Pb).

Note 6—Asphalt binder content can also be calculated using Equation 1 from Method B (Section 8.16).

TEST METHOD B—EXTERNAL BALANCE

TEST PROCEDURES

Oven dry the HMA specimen to a constant mass at a temperature of 110 ± 5°C (230 ± 9°F), ordetermine the moisture content of a companion specimen according to T 329.

Record the asphalt binder correction factor for the specific mix to be tested, as determined by thecorrection factor process in the Annex.

Determine and record the mass of the specimen basket assembly to the nearest 0.1 g.

Prepare the specimen as described in Section 6. Place the specimen baskets in the catch pan. Evenlydistribute the specimen in the basket(s), taking care to keep the material away from the edges of thebasket. Use a spatula or trowel to level the specimen.

Determine and record the total mass of the specimen basket assembly at room temperature to thenearest 0.1 g. Calculate and record the initial mass of the specimen, Mi (total mass minus the mass ofthe specimen basket assembly).

Open the chamber door and place the specimen basket assembly in the furnace. Burn the HMAspecimen in the furnace for at least 45 min.

Note 7—The appropriate time for the initial burn of an HMA specimen is dependent on the specimensize. For large specimens, the time could be significantly longer than 45 min. See the Manufacturer'sInstruction Manual for guidelines.

Open the chamber door, remove the specimen basket assembly, and place it on a cooling plate orblock. Place the protective cage over the specimen basket assembly, and allow it to cool to roomtemperature (approximately 30 min).

Determine and record the total mass of the specimen and specimen basket assembly after cooling tothe nearest 0.1 g.

Place the specimen and specimen basket assembly back into the furnace.

Burn the specimen for at least 15 min after the furnace reaches the set point temperature.

Open the chamber door, remove the specimen and specimen basket assembly, and place it on a coolingplate or block. Place the protective cage over the specimen basket assembly, and allow it to cool toapproximately room temperature (approximately 30 min).

8.

Preheat the ignition furnace to 538± 5°C (1000± 9°F) or the temperature determined by the correctionfactor process in the Annex.

8.1.

8.2.

8.3.

8.4.

8.5.

8.6.

8.7.

8.8.

8.9.

8.10.

8.11.

8.12.

8.13.


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Weigh and record the total mass of the specimen and specimen basket assembly after cooling to thenearest 0.1 g.

Repeat Sections 8.10 through 8.13 until the change in measured mass of the specimen after ignitiondoes not exceed 0.01 percent of the initial specimen mass, Mi.

Note 8—An ending mass loss percentage of 0.02 may be substituted when the aggregate exhibits anexcessive amount of loss during ignition testing. The precision and bias statement was developed using0.01 percent. Both precision and accuracy may be adversely affected by using 0.02 percent. After thetime required to obtain the specified mass loss has been established for each mixture, repeated massdeterminations may not be necessary.

Calculate and record the final mass of the specimen, M (total mass minus the mass of the specimenbasket assembly).

Calculate the asphalt binder content of the specimen as follows:

(1)

where:

Pb = the measured (corrected) asphalt binder content, percent;

Mi = the total mass of the HMA specimen prior to ignition, g;

Mf = the total mass of aggregate remaining after the ignition, g;

CF = the correction factor, percent by mass of HMA specimen; and

MC = the moisture content of the companion HMA specimen, percent, as determined by T 329.(If the specimen was oven dried prior to initiating the procedure, MC = 0.)

GRADATION

Allow the contents of the specimen baskets to cool to room temperature prior to performing thegradation analysis. Empty the contents of the baskets into a flat pan, being careful to capture allmaterial. Use a small wire sieve brush to ensure that any residual fines are removed from the basketsand catch pan.

Perform the gradation analysis according to T 30.

9.

9.1.

9.2.

REPORT

The report shall include the following:

10.

10.1.

10.1.1.


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Test method (A or B);

Corrected asphalt binder content;

Correction factor;

Temperature compensation factor (if applicable);

Specimen mass;

Moisture content (if determined, per T 329); and

Test temperature.

Note 9—If Method A is performed, attach the original printed ticket to the report.

PRECISION AND BIAS

Precision—Criteria for judging the acceptability of ignition burn results for asphalt content obtained byMethod A or Method B are given in Table 2.

Single-Operator Precision—The figures in Column 2 of Table 2 are the standard deviations that havebeen found to be appropriate for the conditions of test described in Column 1. Two results obtained inthe same laboratory, by the same operator using the same equipment, in the shortest practical periodof time, should not be considered suspect unless the difference in the two results exceeds the valuesgiven in Table 2, Column 3.

Multilaboratory Precision—The figures in Column 2 of Table 2 are the standard deviations that havebeen found to be appropriate for the conditions of test described in Column 1. Two results submitted bytwo different operators testing the same material in different laboratories shall not be consideredsuspect unless the difference in the two results exceeds the values given in Table 2, Column 3.

Table 2—Precision Estimates

Note 10—The precision estimates given in Table 2 are based on the analysis of test results from threepairs of AMRL proficiency samples. The data analyzed consisted of results from 353 to 461 laboratoriesfor each of the three pairs of samples. The analysis included two binder grades: PG 52-34 and PG64-22. Average results for asphalt content ranged from 4.049 to 5.098 percent. The details of thisanalysis are in NCHRP Final Report, NCHRP Project No. 9-26, Phase 3.

Note 11—The precision estimates are based on four aggregate types, four replicates, and twelvelaboratories participating with no laboratory results deleted as outlying observations. All four aggregateswere tested in surface mixes and had relatively low absorption values.

11.

11.1.

11.1.1.

11.1.2.

11.2.


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Bias—Any biases inherent to the ignition oven process used for Test Methods A and B, when testing forasphalt content and aggregate gradation, are accounted for by the determination and application ofappropriate correction factors.

KEYWORDS

Aggregate; asphalt binder; asphalt binder content; asphalt mixture; convection; correction factor; directinfrared irradiation; external balance; gradation; hot mix asphalt; ignition; ignition furnace; internalbalance.

12.

12.1.

ANNEX A—CORRECTION FACTORS(Mandatory Information)

ASPHALT BINDER AND AGGREGATE

Asphalt binder content results may be affected by the type of aggregate in the mixture and the ignitionfurnace. Therefore, asphalt binder and aggregate correction factors must be established by testing a setof correction specimens for each job mix formula (JMF) mix design. Correction factor(s) must bedetermined before any acceptance testing is completed and repeated each time a change in the mixingredients or design occurs. Any changes greater than 5 percent in stockpiled aggregate proportionsshould require a new correction factor. Historical data or scientific studies may be used to determinethe correction factor(s) in lieu of using this testing procedure if the testing agency provides reference tothe studies/data.

Asphalt Binder Correction Factor—Certain aggregate types may result in unusually high correctionfactors (greater than 1.0 percent). Such mixes should be corrected and tested at a lower temperature,as described below. Each ignition furnace will have its own unique asphalt binder correction factordetermined in the location where testing will be performed.

Aggregate Correction Factor—Due to potential aggregate breakdown during the ignition process, anaggregate correction factor will be determined for each ignition furnace in the location where testingwill be performed when the following conditions occur: aggregates that have a proven history ofexcessive breakdown or aggregates from an unknown source.

A1.

A1.1.

A1.2.

A1.3.

CORRECTION FACTOR PROCEDURE

Obtain samples of aggregate in accordance with T 2. Reduce the samples to testing size as neededaccording to R 76.

Obtain samples of asphalt binder in accordance with R 66.

Note A1—Include other additives that may be required by the JMF.

Prepare an initial, or “butter” mix at the design asphalt binder content. Mix and discard the butter mixprior to preparing any of the correction specimens to ensure an accurate asphalt binder content.

Prepare two correction specimens at the JMF design asphalt binder content and gradation. Aggregateused for correction specimens shall be sampled from the material designated for use in production. An

A2.

A2.1.

A2.2.

A2.3.

A2.4.


8 of 9 8/8/17, 11:12 AM

additional “blank” (aggregate only) specimen shall be batched at the JMF gradation. Determine anaggregate gradation in accordance with T 30 on the “blank” specimen.

Place the freshly mixed specimens directly into the specimen basket assembly. If specimens are allowedto cool prior to placement in the specimen basket assembly, the specimens must be dried to constantmass at a temperature of 110 ± 5°C (230 ± 9°F). Do not preheat the specimen basket assembly.

Test the specimens in accordance with Method A or Method B of the procedure.

Once both of the correction specimens have been burned, determine the asphalt binder content foreach specimen by calculation or from the printed oven tickets, if available.

If the difference between the asphalt binder contents of the two specimens exceeds 0.15 percent,repeat Section A2.3 through A2.7 with two more specimens and, from the four results, discard the highand low result. Determine the correction factor from the two original or remaining results asappropriate. Calculate the difference between the actual and measured asphalt binder contents for eachspecimen. The asphalt binder correction factor, CF, is the average of the differences expressed as apercentage by mass of the HMA.

Note A2—The temperature for determining the asphalt binder content of HMA specimens by thisprocedure shall be the same temperature determined for the correction specimens.

For the direct IR irradiation-type furnaces, the Default burn profile should be used for most materials.The operator may select burn-profile Option 1 or Option 2 to optimize the burn cycle. Option 1 isdesigned for aggregate that requires a large asphalt binder correction factor (greater than 1 percent)—typically very soft aggregate (such as dolomite). Option 2 is designed for samples that may not burncompletely using the Default burn profile. The burn profile for testing HMA samples shall be the sameburn profile selected for correction samples.

Perform a gradation analysis on the residual aggregate in accordance with T 30, if required. The resultswill be utilized in developing an aggregate correction factor and should be calculated and reported tothe nearest 0.1 percent.

From the gradation results, subtract the percent passing each sieve for each specimen from the percentpassing each sieve of the “blank” specimen gradation results from Section A2.4.

Determine the average difference for the two values. If the difference for any single sieve exceeds theallowable difference for that sieve as listed in Table A2.1, then aggregate gradation correction factors(equal to the resultant average differences) for all sieves shall be applied to all acceptance gradationtest results determined by T 30, prior to final rounding and reporting. If the 0.075-mm (No. 200) sieveis the only sieve outside the limits in Table A2.1, apply the aggregate correction factor to only the0.075-mm (No. 200) sieve.

Table A2.1—Permitted Sieving Difference

If the asphalt binder correction factor exceeds 1.0 percent, the test temperature should be lowered to482 ± 5°C (900 ± 9°F) for a convection type furnace. If there is no improvement in the correctionfactor, it is permissible to use the higher temperature.

A2.8.1.


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Standard Method of Test for Materials Finer Than 75-μm (No. 200)Sieve in Mineral Aggregates by Washing

AASHTO Designation: T 11-05 (2013)1

ASTM Designation: C117-13

This test method covers determination of the amount of material finer than a 75-μm (No. 200) sieve inaggregate by washing. Clay particles and other aggregate particles that are dispersed by the washwater, as well as water-soluble materials, will be removed from the aggregate during the test.

Two procedures are included, one using only water for the washing operation, and the other including awetting agent to assist the loosening of the material finer than the 75-μm (No. 200) sieve from thecoarser material. Unless otherwise specified, Procedure A (water only) shall be used.


This standard may involve hazardous materials, operations, and equipment. This standard does notpurport to address all of the safety concerns associated with its use. It is the responsibility of the userof this procedure to establish appropriate safety and health practices and to determine the applicabilityof regulatory limitations prior to its use.

SCOPE1.

1.1.

1.2.

1.3.

1.4.

AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsR 76, Reducing Samples of Aggregate to Testing SizeT 2, Sampling of AggregatesT 27, Sieve Analysis of Fine and Coarse Aggregates

ASTM Standards:

C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods forConstruction MaterialsE11, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves

REFERENCED DOCUMENTS2.

2.1.

2.2.

A sample of the aggregate is washed in a prescribed manner, using either plain water or watercontaining a wetting agent, as specified. The decanted wash water, containing suspended and dissolvedmaterial, is passed through a 75-μm (No. 200) sieve. The loss in mass resulting from the washtreatment is calculated as mass percent of the original sample and is reported as the percentage ofmaterial finer than a 75-μm (No. 200) sieve by washing.

SUMMARY OF METHOD3.

3.1.

4

Standard Method of Test for Materials Finer Than 75-μm (No. 200) Sieve... http://hm.digital.transportation.org/HM/Part_II_Tests/Aggregate/t_002.a...

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Material finer than the 75-μm (No. 200) sieve can be separated from larger particles much moreefficiently and completely by wet sieving than through the use of dry sieving. Therefore, when accuratedeterminations of material finer than 75 μm in fine or coarse aggregate are desired, this test method isused on the sample prior to dry sieving in accordance with T 27. The results of this test method areincluded in the calculation in T 27, and the total amount of material finer than 75 μm by washing, plusthat obtained by dry sieving the same sample, is reported with the results of T 27. Usually theadditional amount of material finer than 75 μm obtained in the dry-sieving process is a small amount. Ifit is large, the efficiency of the washing operation should be checked. A large amount of material couldalso be an indication of the degradation of the aggregate.

Plain water is adequate to separate the material finer than 75 μm from the coarser material in mostaggregates. In some cases, the finer material is adhered to the larger particles, such as in some claycoatings and coatings on aggregates that have been extracted from bituminous mixtures. In thesecases, the fine material will be separated more readily with a wetting agent in the water.


Balance—The balance shall have sufficient capacity, be readable to 0.1 percent of the sample mass orbetter, and conform to the requirements of M 231.

Sieves—A nest of two sieves, the lower being a 75-μm (No. 200) sieve and the upper being a sieve withopenings in the range of 2.36 mm (No. 8) to 1.18 mm (No. 16), both conforming to the requirement ofASTM E11.

Container—A pan or vessel of a size sufficient to contain the sample covered with water and to permitvigorous agitation without loss of any part of the sample or water.

Oven—An oven of sufficient size, capable of maintaining a uniform temperature of 110 ± 5°C (230 ±9°F).

Wetting Agent—Any dispersing agent, such as liquid dishwashing detergents, that will promoteseparation of the fine materials.

Note 1—The use of a mechanical apparatus to perform the washing operation is not precluded,provided the results are consistent with those obtained using manual operations. The use of somemechanical washing equipment with some samples may cause degradation of the sample.

APPARATUS AND MATERIALS5.

5.1.

5.2.

5.3.

5.4.

5.5.

Sample the aggregate in accordance with T 2. If the same test sample is to be tested for sieve analysisaccording to T 27, comply with the applicable requirements of that method.

Thoroughly mix the sample of aggregate to be tested and reduce the quantity to an amount suitable fortesting using the applicable methods described in R 76. If the same test sample is to be testedaccording to T 27, the minimum mass shall be as described in the applicable sections of that method.Otherwise, the mass of the test sample, after drying, shall conform with the following:

SAMPLING6.

6.1.

6.2.


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The test sample shall be the end result of the reduction. Reduction to an exact predetermined massshall not be permitted. If the nominal maximum size of the aggregate to be tested is not listed above,the next larger size listed shall be used to determine sample size.

Procedure A shall be used, unless otherwise specified by the specification with which the test results areto be compared, or when directed by the agency for which the work is performed.

SELECTION OF PROCEDURE7.

7.1.

Dry the test sample to constant mass at a temperature of 110 ± 5°C (230 ± 9°F). Determine the massto the nearest 0.1 percent of the mass of the test sample.

If the applicable specification requires that the amount passing the 75-μm (No. 200) sieve shall bedetermined on a portion of the sample passing a sieve smaller than the nominal maximum size of theaggregate, separate the sample on the designated sieve and determine the mass of the materialpassing the designated sieve to 0.1 percent of the mass of this portion of the test sample. Use thismass as the original dry mass of the test sample in Section 10.1.

Note 2—Some specifications for aggregates with a nominal maximum size of 50 mm or greater, forexample, provide a limit for material passing the 75-μm (No. 200) sieve determined on that portion ofthe sample passing the 25.0-mm sieve. Such procedures are necessary because it is impractical to washsamples of the size required when the same test sample is to be used for sieve analysis by T 27.

After drying and determining the mass, place the test sample in the container and add sufficient waterto cover it. No detergent, dispersing agent, or other substance shall be added to the water. Agitate thesample with sufficient vigor to result in complete separation of all particles finer than the 75-μm (No.200) sieve from the coarser particles, and to bring the fine material into suspension. The use of a largespoon or other similar tool to stir and agitate the aggregate in the wash water has been foundsatisfactory. Immediately pour the wash water containing the suspended and dissolved solids over thenested sieves, arranged with the coarser sieve on top. Take care to avoid, as much as feasible, thedecantation of coarser particles of the sample.

Add a second charge of water to the sample in the container, agitate, and decant as before. Repeat thisoperation until the wash water is clear.

Note 3—If mechanical washing equipment is used, the charging of water, agitating, and decanting maybe a continuous operation.

Note 4—A spray nozzle or a piece of rubber tubing attached to a water faucet may be used to rinseany of the material that may have fallen onto the sieves. The velocity of water, which may be increasedby pinching the tubing or by use of a nozzle, should not be sufficient to cause any splashing of thesample over the sides of the sieve.

PROCEDURE A—WASHING WITH PLAIN WATER8.

8.1.

8.2.

8.3.

8.4.

8.5.


3 of 6 8/8/17, 11:03 AM

Return all material retained on the nested sieves by flushing into the container containing the washedsample. Dry the washed aggregate to constant mass at a temperature of 110 ± 5°C (230 ± 9°F) anddetermine the mass to the nearest 0.1 percent of the original mass of the sample.

Note 5—Following the washing of the sample and flushing any materials retained on the 75-μm (No.200) sieve back into the container, no water should be decanted from the container except through the75-μm sieve, to avoid loss of material. Excess water from flushing should be evaporated from thesample in the drying process.

Prepare the sample in the same manner as for Procedure A.

After drying and determining the mass, place the test sample in the container. Add sufficient water tocover the sample, and add wetting agent to the water (Note 6). Agitate the sample with sufficient vigorto result in complete separation of all particles finer than the 75-μm (No. 200) sieve from the coarserparticles, and to bring the fine material into suspension. The use of a large spoon or other similar toolto stir and agitate the aggregate in the wash water has been found satisfactory. Immediately pour thewash water containing the suspended and dissolved solids over the nested sieves, arranged with thecoarser sieve on top. Take care to avoid, as much as feasible, the decantation of coarser particles of thesample.

Note 6—There should be enough wetting agent to produce a small amount of suds when the sample isagitated. The quantity will depend on the hardness of the water and the quality of the detergent.Excessive suds may overflow the sieves and carry some material with them.

Add a second charge of water (without wetting agent) to the sample in the container, agitate, anddecant as before. Repeat this operation until the wash water is clear.

Complete the test as for Procedure A.

PROCEDURE B—WASHING USING A WETTING AGENT9.

9.1.

9.2.

9.3.

9.4.

Calculate the amount of material passing a 75-μm (No. 200) sieve by washing as follows:

(1)

where:

A = percentage of material finer than a 75-μm (No. 200) sieve by washing;

B = original dry mass of sample, g; and

C = dry mass of sample after washing, g.

CALCULATION10.

10.1.

REPORT11.


4 of 6 8/8/17, 11:03 AM

Report the percentage of material finer than the 75-μm (No. 200) sieve by washing to the nearest 0.1percent, except if the result is 10 percent or more, report the percentage to the nearest whole number.

Include a statement as to which procedure was used.

Precision—The estimates of precision of this test method listed in Table 1 are based on results from theAASHTO Materials Reference Laboratory Proficiency Sample Program, with testing conducted by thistest method and ASTM C117. The significant differences between the methods at the time the datawere acquired is that T 11 required, and ASTM C117 prohibited, the use of a wetting agent. The dataare based on the analyses of more than 100 paired test results from 40 to 100 laboratories.

Table 1—Precision

The precision values for fine aggregate in Table 1 are based on nominal 500-g test samples. Revision ofthis test method in 1996 permits the fine aggregate test sample size to be 300 g minimum. Analysis ofresults of testing of 300-g and 500-g test samples from Aggregate Proficiency Test Samples 99 and 100(Samples 99 and 100 were essentially identical) produced the precision values in Table 2, whichindicates only minor differences due to test sample size.

Table 2—Precision Data for 300-g and 500-g Test Samples

Note 7—The values for fine aggregate in Table 1 will be revised to reflect the 300-g test sample sizewhen a sufficient number of Aggregate Proficiency Tests have been conducted using that sample size toprovide reliable data.

Bias—Because there is no accepted reference material suitable for determining the bias for theprocedure in this test method, no statement on bias is made.

PRECISION AND BIAS12.

12.1.

12.1.1.

12.2.


5 of 6 8/8/17, 11:03 AM

Aggregate; size analysis; wash loss; 75-µm (No. 200) sieve.

1 Except for Sections 5.1 and 6.2, and Note 4, this test method is identical to ASTM C117-13.

KEYWORDS13.

13.1.


6 of 6 8/8/17, 11:03 AM

Standard Practice for Reducing Samples of Aggregate to Testing SizeAASHTO Designation: R 76-161,2


ASTM Designation: C702/C702M-11

SCOPE

These methods cover the reduction of large samples of aggregate to the appropriate size for testing,employing techniques that are intended to minimize variations in measured characteristics between thetest samples so selected and the large sample.


1.

1.1.

1.2.

This standard does not purport to address all of the safety concerns associated with its use. It is theresponsibility of the user of this procedure to establish appropriate safety and health practices and todetermine the applicability of regulatory limitations prior to its use.

1.3.


AASHTO Standards:

T 2, Sampling of AggregatesT 84, Specific Gravity and Absorption of Fine Aggregate

ASTM Standard:

C125, Standard Terminology Relating to Concrete and Concrete Aggregates

2.

2.1.

2.2.

TERMINOLOGY

Definitions—the terms used in this standard are defined in ASTM C125.

3.

3.1.


Specifications for aggregates require sampling portions of the material for testing. Other factors beingequal, larger samples will tend to be more representative of the total supply. The methods described inthis standard provide for reducing the large sample obtained in the field or produced in the laboratoryto a convenient size for conducting a number of tests to describe the material and measure its quality.These methods are conducted in such a manner that the smaller test sample portion will berepresentative of the larger sample and, thus, of the total supply. The individual test methods providefor minimum masses of material to be tested.

Under certain circumstances, reduction in size of the large sample prior to testing is not recommended.Substantial differences between the selected test samples sometimes cannot be avoided, as, for

4.

4.1.

4.2.

Standard Method of Test for Reducing Samples of Aggregate to Testing Size http://hm.digital.transportation.org/HM/Part_III_Practices/Concrete/r_0...

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example, in the case of an aggregate having relatively few large-sized particles in the sample. The lawsof chance dictate that these few particles may be unequally distributed among the reduced-size testsamples. Similarly, if the test sample is being examined for certain contaminants occurring as a fewdiscrete fragments in only small percentages, caution should be used in interpreting results from thereduced-size test sample. Chance inclusion or exclusion of only one or two particles in the selected testsample may importantly influence interpretation of the characteristics of the original sample. In thesecases, the entire original sample should be tested.

Failure to carefully follow the procedures in these methods could result in providing a nonrepresentativesample to be used in subsequent testing.

SELECTION OF METHOD

Fine Aggregate—Samples of fine aggregate that are drier than the saturated surface-dry condition(Note 1) shall be reduced in size by a mechanical splitter according to Method A. Samples having freemoisture on the particle surfaces may be reduced in size by quartering according to Method B, or bytreating as a miniature stockpile as described in Method C.

If the use of Method B or Method C is desired, and the sample does not have free moisture on theparticle surfaces, the sample may be moistened to achieve this condition, thoroughly mixed, and thenthe sample reduction performed.

Note 1—The method of determining the saturated surface-dry condition is described in T 84. As aquick approximation, if the fine aggregate will retain its shape when molded in the hand, it may beconsidered to be wetter than saturated surface-dry.

If use of Method A is desired and the sample has free moisture on the particle surfaces, the entiresample may be dried to at least the surface-dry condition, using temperatures that do not exceed thosespecified for any of the tests contemplated, and then the sample reduction performed. Alternatively, ifthe moist sample is very large, a preliminary split may be made using a mechanical splitter having widechute openings 38 mm (11/2 in.) or more to reduce the sample to not less than 5000 g. The portion soobtained is then dried, and reduction to test sample size is completed using Method A.

Coarse Aggregates—Reduce the sample using a mechanical splitter in accordance with Method A(preferred method) or by quartering in accordance with Method B. The miniature stockpile Method C isnot permitted for coarse aggregates or mixtures of coarse and fine aggregates.

Combined Coarse and Fine Aggregate—Samples that are in a dry condition may be reduced in size byeither Method A or Method B. Samples having free moisture on the particle surfaces may be reduced insize by quartering according to Method B. When Method A is desired and the sample is damp or showsfree water, dry the sample until it appears dry or until clumps can be easily broken by hand (Note 2).Dry the entire sample to this condition, using temperatures that do not exceed those specified for anyof the tests contemplated, and then reduce the sample. The miniature stockpile Method C is notpermitted for combined aggregates.

Note 2—The dryness of the sample can be tested by tightly squeezing a small portion of the sample inthe palm of the hand. If the cast crumbles readily, the correct moisture range has been obtained.

5.

5.1.

5.1.1.

5.1.2.

5.2.

5.3.

SAMPLING

The samples of aggregate obtained in the field shall be taken in accordance with T 2, or as required byindividual test methods. When tests for sieve analysis only are contemplated, the size of field samplelisted in T 2 is usually adequate. When additional tests are to be conducted, the user shall determine

6.

6.1.


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that the initial size of the field sample is adequate to accomplish all intended tests. Similar proceduresshall be used for aggregate produced in the laboratory.

METHOD A—MECHANICAL SPLITTER

APPARATUS

Sample Splitter—Sample splitters shall have an even number of equal-width chutes, but not less than atotal of eight for coarse aggregate, or twelve for fine aggregate, which discharge alternatively to eachside of the splitter. For coarse aggregate and mixed aggregate, the minimum width of the individualchutes shall be approximately 50 percent larger than the largest particles in the sample to be split (Note3). For dry fine aggregate in which the entire sample will pass the 9.5-mm (3/8-in.) sieve, the minimumwidth of the individual chutes shall be at least 50 percent larger than the largest particles in the sampleand the maximum width shall be 19 mm (3/4 in.). The splitter shall be equipped with two receptacles tohold the two halves of the sample following splitting. It shall also be equipped with a hopper orstraightedged pan, which has a width equal to or slightly less than the overall width of the assembly ofchutes, by which the sample may be fed at a controlled rate to the chutes. The splitter and accessoryequipment shall be so designed that the sample will flow smoothly without restriction or loss of material(see Figure 1).

7.

7.1.


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Figure 1—Sample Splitters (Riffles)

Note 3—Mechanical splitters are commonly available in sizes adequate for coarse aggregate having thelargest particle not over 37.5 mm (11/2 in.).

PROCEDURE

Place the original sample in the hopper or pan and uniformly distribute it from edge to edge, so thatwhen it is introduced into the chutes, approximately equal amounts will flow through each chute. Therate at which the sample is introduced shall be such as to allow free flowing through the chutes into thereceptacles below.

8.

8.1.

8.2.


4 of 8 8/8/17, 10:42 AM

Reintroduce the portion of the sample in one of the receptacles into the splitter as many times asnecessary to reduce the sample to the size specified for the intended test. The portion of the materialcollected in the other receptacle may be reserved for reduction in size for other tests.

METHOD B—QUARTERING

APPARATUS

Apparatus shall consist of a straightedge; straightedged scoop, shovel or trowel; a broom or brush; anda canvas blanket or tear-resistant tarp approximately 2 by 2.5 m (6 by 8 ft).

9.

9.1.

PROCEDURE

Use either the procedure described in Section 10.1.1 or 10.1.2, or a combination of both.

Place the original sample on a hard, clean, level surface where there will be neither loss of material northe accidental addition of foreign material. Mix the material by turning the entire sample over at leastthree times until the material is thoroughly mixed. With the last turning, form the entire sample into aconical pile by depositing individual lifts on top of the preceding lift. Carefully flatten the conical pile to auniform thickness and diameter by pressing down the apex with a shovel or trowel so that each quartersector of the resulting pile will contain the material originally in it. The diameter should beapproximately four to eight times the thickness. Divide the flattened mass into four equal quarters witha shovel or trowel and remove two diagonally opposite quarters, including all fine material, and brushthe cleared spaces clean. The two unused quarters may be set aside for later use or testing, if desired.Successively mix and quarter the remaining material until the sample is reduced to the desired size (seeFigure 2).

As an alternative to the procedure in Section 10.1.1 or when the floor surface is uneven, the fieldsample may be placed on a canvas blanket or tear-resistant tarp and mixed with a shovel or trowel asdescribed in Section 10.1.1, leaving the sample in a conical pile. As an alternative to mixing with theshovel or trowel, lift each corner of the blanket or tarp and pull it over the sample toward the diagonallyopposite corner, causing the material to be rolled. After the material has been rolled a sufficient numberof times (a minimum of four times), so that it is thoroughly mixed, pull each corner of the blanket ortarp toward the center of the pile so the material will be left in a conical pile. Flatten the pile asdescribed in Section 10.1.1. Divide the sample as described in Section 10.1.1, or insert a stick or pipebeneath the blanket or tarp and under the center of the pile, then lift both ends of the stick, dividingthe sample into two equal parts. Remove the stick, leaving a fold of the blanket between the dividedportions. Insert the stick under the center of the pile at right angles to the first division and again liftboth ends of the stick, dividing the sample into four equal parts. Remove two diagonally oppositequarters, being careful to clean the fines from the blanket or tarp. The two unused quarters may be setaside for later use or testing, if desired. Successively mix and quarter the remaining material until thesample is reduced to the desired size (see Figure 3).

10.

10.1.

10.1.1.

10.1.2.


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Figure 2—Quartering on a Hard, Clean, Level Surface


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Figure 3—Quartering on a Canvas Blanket or Tear-Resistant Tarp

METHOD C—MINIATURE STOCKPILE SAMPLING (DAMP FINE AGGREGATEONLY)

APPARATUS

Apparatus shall consist of a straightedge; straightedged scoop, shovel, or trowel for mixing theaggregate; and either a small sampling thief, small scoop, or spoon for sampling.

11.

11.1.

PROCEDURE

Place the original sample of damp fine aggregate on a hard, clean, level surface where there will beneither loss of material nor the accidental addition of foreign material. Mix the material by turning theentire sample over at least three times until the material is thoroughly mixed. With the last turning,form the entire sample into a conical pile by depositing individual lifts on top of the preceding lift. Ifdesired, the conical pile may be flattened to a uniform thickness and diameter by pressing the apexwith a shovel or trowel so that each quarter sector of the resulting pile will contain the material

12.

12.1.


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1 Technically equivalent but not identical to ASTM C702/C702M-11.

originally in it. Obtain a sample for each test by selecting at least five increments of material at randomlocations from the miniature stockpile, using any of the sampling devices described in Section 11.1.

KEYWORDS

Aggregate; aggregate sample; mechanical splitter; quartering.

13.

13.1.

2 Formerly T 248. First published as a practice in 2016.


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Standard Method of Test for Sieve Analysis of Fine and CoarseAggregates

AASHTO Designation: T 27-141,2

ASTM Designation: C136-06

This method covers the determination of the particle size distribution of fine and coarse aggregates bysieving.

Some specifications for aggregates, which reference this method, contain grading requirementsincluding both coarse and fine fractions. Instructions are included for sieve analysis of such aggregates.

The values stated in SI units are to be regarded as the standard. The values in parentheses areprovided for information purposes only.

This standard may involve hazardous materials, operations, and equipment. This standard does notpurport to address all of the safety concerns associated with its use. It is the responsibility of the userof this procedure to consult and establish appropriate safety and health practices and to determine theapplicability of regulatory regulations prior to its use.

SCOPE1.

1.1.

1.2.

1.3.

1.4.

AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsR 76, Reducing Samples of Aggregate to Testing SizeT 2, Sampling of AggregatesT 11, Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing

ASTM Standards:

C125, Standard Terminology Relating to Concrete and Concrete AggregatesC670, Standard Practice for Preparing Precision and Bias Statements for Test Methods forConstruction MaterialsE11, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves

IEEE/ASTM Standard:

SI10, American National Standard for Metric Practice

REFERENCED DOCUMENTS2.

2.1.

2.2.

2.3.

Definitions—For definitions of terms used in this standard, refer to ASTM C125.

TERMINOLOGY3.

3.1.

SUMMARY OF METHOD4.

Standard Method of Test for Sieve Analysis of Fine and Coarse Aggregates http://hm.digital.transportation.org/HM/Part_II_Tests/Aggregate/t_005.a...

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A sample of dry aggregate of known mass is separated through a series of sieves of progressivelysmaller openings for determination of particle size distribution.

This method is used primarily to determine the grading of materials proposed for use as aggregates orbeing used as aggregates. The results are used to determine compliance of the particle size distributionwith applicable specification requirements and to provide necessary data for control of the production ofvarious aggregate products and mixtures containing aggregates. The data may also be useful indeveloping relationships concerning porosity and packing.

Accurate determination of material finer than the 75-μm (No. 200) sieve cannot be achieved by use ofthis method alone. T 11 for material finer than the 75-μm (No. 200) sieve by washing should beemployed.

SIGNIFICANCE AND USE5.

5.1.

5.2.

Balance—The balance shall have sufficient capacity, be readable to 0.1 percent of the sample mass, orbetter, and conform to the requirements of M 231.

Sieves—The sieve cloth shall be mounted on substantial frames constructed in a manner that willprevent loss of material during sieving. The sieve cloth and standard sieve frames shall conform to therequirements of ASTM E11. Nonstandard sieve frames shall conform to the requirements of ASTM E11as applicable.

Note 1—It is recommended that sieves mounted in frames larger than standard 203.2 mm (8 in.)diameter be used for testing coarse aggregate to reduce the possibility of overloading the sieves. SeeSection 8.3.

Mechanical Sieve Shaker—A mechanical sieving device, if used, shall create motion of the sieves tocause the particles to bounce, tumble, or otherwise turn so as to present different orientations to thesieving surface. The sieving action shall be such that the criterion for adequacy of sieving described inSection 8.4 is met in a reasonable time period.

Note 2—Use of a mechanical sieve shaker is recommended when the size of the sample is 20 kg (44lb) or greater, and may be used for smaller samples, including fine aggregate. Excessive time (morethan approximately 10 min) to achieve adequate sieving may result in degradation of the sample. Thesame mechanical sieve shaker may not be practical for all sizes of samples because the large sievingarea needed for practical sieving of a large nominal size coarse aggregate very likely could result in lossof a portion of the sample if used for a smaller sample of coarse aggregate or fine aggregate.

Oven—An oven of appropriate size capable of maintaining a uniform temperature of 110 ± 5°C (230 ±9°F).

APPARATUS6.

6.1.

6.2.

6.3.

6.4.

Sample the aggregate in accordance with T 2. The mass of the field sample shall be the mass shown inT 2 or four times the mass required in Sections 7.4 and 7.5 (except as modified in Section 7.6),whichever is greater.

Thoroughly mix the sample and reduce it to an amount suitable for testing using the applicable

SAMPLING7.

7.1.

7.2.


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Coarse and Fine Aggregates Mixtures—The mass of the test sample of coarse and fine aggregatemixtures shall be the same as for coarse aggregate in Section 7.4.

Samples of Large-Size Coarse Aggregate—The size of sample required for aggregate with 50-mm (2-in.)nominal maximum size or larger is such as to preclude convenient sample reduction and testing as aunit except with large mechanical splitters and sieve shakers. As an option when such equipment is notavailable, instead of combining and mixing sample increments and then reducing the field sample totesting size, conduct the sieve analysis on a number of approximately equal sample increments suchthat the total mass tested conforms to the requirements of Section 7.4.

In the event that the amount of material finer than the 75-μm (No. 200) sieve is to be determined by T11, use the procedure described in Section 7.7.1 or 7.7.2, whichever is applicable.

For aggregates with a nominal maximum size of 12.5 mm (1/2 in.) or less, use the same test sample fortesting by T 11 and this method. First test the sample in accordance with T 11 through the final dryingoperation, then dry sieve the sample as stipulated in Sections 8.2 through 8.6 of this method.

For aggregates with a nominal maximum size greater than 12.5 mm (1/2 in.), a single test sample maybe used as described in Section 7.7.1 or separate test samples may be used for T 11 and this method.

Where the specification requires determination of the total amount of material finer than the 75-μm(No. 200) sieve by washing and dry sieving, use the procedure described in Section 7.7.1.

procedures described in R 76. The sample for test shall be the approximate mass desired when dry andshall be the end result of the reduction. Reduction to an exact predetermined mass shall not bepermitted.

Note 3—Where sieve analysis, including determination of material finer than the 75-μm (No. 200)sieve, is the only testing proposed, the size of the sample may be reduced in the field to avoid shippingexcessive quantities of extra material to the laboratory.

Fine Aggregate—The size of the test sample of aggregate, after drying, shall be 300 g minimum.

Coarse Aggregate—The mass of the test sample of coarse aggregate shall conform with the following:

PROCEDURE8.


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If the test sample has not been subjected to testing by T 11, dry it to constant mass at a temperatureof 110 ± 5°C (230 ± 9°F). Determine and record the mass of material that will be placed on the sievesto the accuracy of the balance as defined in Section 6.1.

Note 4—For control purposes, particularly where rapid results are desired, it is generally not necessaryto dry coarse aggregate for the sieve analysis test. The results are little affected by the moisturecontent unless (1) the nominal maximum size is smaller than about 12.5 mm (1/2 in.), (2) the coarseaggregate contains appreciable material finer than 4.75 mm (No. 4), or (3) the coarse aggregate ishighly absorptive (a lightweight aggregate, for example). Also, samples may be dried at the highertemperature associated with the use of hot plates without affecting results, provided steam escapeswithout generating pressures sufficient to fracture the particles, and temperatures are not so great asto cause chemical breakdown of the aggregate.

Select sieves with suitable openings to furnish the information required by the specifications coveringthe material to be tested. Use additional sieves as desired or necessary to provide other information,such as fineness modulus, or to regulate the amount of material on a sieve. Nest the sieves in order ofdecreasing size of opening from top to bottom and place the sample, or portion of the sample if it is tobe sieved in more than one increment, on the top sieve. Agitate the sieves by hand or by mechanicalapparatus for a sufficient period, established by trial or checked by measurement on the actual testsample, to meet the criterion for adequacy of sieving described in Section 8.4.

Limit the quantity of material on a given sieve so that all particles have opportunity to reach sieveopenings a number of times during the sieving operation. For sieves with openings smaller than 4.75-mm (No. 4), the quantity retained on any sieve at the completion of the sieving operation shall notexceed 7 kg/m2 (4 g/in.2) of sieving surface area (Note 5). For sieves with openings 4.75 mm (No. 4)and larger, the quantity retained in kg shall not exceed the product of 2.5 × (sieve opening, mm ×(effective sieving area, m2)). This quantity is shown in Table 1 for five sieve-frame dimensions incommon use. In no case shall the quantity retained be so great as to cause permanent deformation ofthe sieve cloth.

Prevent an overload of material on an individual sieve by one or a combination of the followingmethods:

Insert an additional sieve with opening size intermediate between the sieve that may be overloaded andthe sieve immediately above that sieve in the original set of sieves.

Split the sample into two or more portions, sieving each portion individually. Combine the masses of theseveral portions retained on a specific sieve before calculating the percentage of the sample on thesieve.

Use sieves having a larger frame size and providing greater sieving area.

Note 5—The 7 kg/m2 amounts to 200 g for the usual 203.2-mm (8-in.) diameter sieve (with effectivesieving surface diameter of 190.5 mm (7.5 in.)).

In the case of coarse and fine aggregate mixtures, the portion of the sample finer than the 4.75-mm(No. 4) sieve may be distributed among two or more sets of sieves to prevent overloading of individualsieves.

Alternatively, the portion finer than the 4.75-mm (No. 4) sieve may be reduced in size using amechanical splitter according to R 76. If this procedure is followed, compute the mass of each sizeincrement of the original sample as follows:

(1)


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where:

A = mass of size increment on total sample basis;

W1 = mass of fraction finer than 4.75-mm (No. 4) sieve in total sample;

W2 = mass of reduced portion of material finer than 4.75-mm (No. 4) sieve actually sieved; and

B = mass of size increment in reduced portion sieved.

Table 1—Maximum Allowable Quantity of Material Retained on a Sieve, kg

Continue sieving for a sufficient period and in such manner that, after completion, not more than 0.5percent by mass of the total sample passes any sieve during 1 min of continuous hand sievingperformed as follows: Hold the individual sieve, provided with a snug-fitting pan and cover, in a slightlyinclined position in one hand. Strike the side of the sieve sharply and with an upward motion againstthe heel of the other hand at the rate of about 150 times per minute, turn the sieve about one sixth ofa revolution at intervals of about 25 strokes. In determining sufficiency of sieving for sizes larger thanthe 4.75-mm (No. 4) sieve, limit the material on the sieve to a single layer of particles. If the size of themounted testing sieves makes the described sieving motion impractical, use 203.2-mm (8-in.) diametersieves to verify the sufficiency of sieving.

Unless a mechanical sieve shaker is used, hand sieve particles obtained on the 75 mm (3 in.) bydetermining the smallest sieve opening through which each particle will pass by rotating the particles, ifnecessary, in order to determine whether they will pass through a particular opening; however, do notforce particles to pass through an opening.


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Determine the mass of each size increment on a scale or balance conforming to the requirementsspecified in Section 6.1 to the nearest 0.1 percent of the total original dry sample mass. The total massof the material after sieving should check closely with the total original dry mass of the sample placedon the sieves. If the two amounts differ by more than 0.3 percent, based on the total original drysample mass, the results should not be used for acceptance purposes.

CALCULATION

Calculate percentages passing, total percentages retained, or percentages in various size fractions tothe nearest 0.1 percent on the basis of the total mass of the initial dry sample. If the same test samplewas first tested by T 11, include the mass of material finer than 75-μm (No. 200) sieve by washing inthe sieve analysis calculation; and use the total dry sample mass prior to washing in T 11 as the basisfor calculating all the percentages.

When sample increments are tested as provided in Section 7.6, total the masses of the portion of theincrements retained on each sieve, and use these masses to calculate the percentage as in Section 9.1.

Calculate the fineness modulus, when required, by adding the total percentages of material in thesample that are coarser than each of the following sieves (cumulative percentages retained), anddividing the sum by 100; 150 μm (No. 100), 300 μm (No. 50), 600 μm (No. 30), 1.18 mm (No. 16),2.36 mm (No. 8), 4.75 mm (No. 4), 9.5 mm (3/8 in.), 19.0 mm (3/4 in.), 37.5 mm (11/2 in.), and larger,increasing the ratio of 2 to 1.

9.

9.1.

9.1.1.

9.2.

REPORT

Depending on the form of the specifications for use of the material under test, the report shall includeone of the following:

Total percentage of material passing each sieve, or

Total percentage of material retained on each sieve, or

Percentage of material retained between consecutive sieves.

Report percentages to the nearest whole number, except if the percentage passing the 75-μm (No.200) sieve is less than 10 percent, it shall be reported to the nearest 0.1 percent.

Report the fineness modulus, when required, to the nearest 0.01.

10.

10.1.

10.1.1.

10.1.2.

10.1.3.

10.2.

10.3.

PRECISION AND BIAS

Precision—The estimates of precision for this test method are listed in Table 2. The estimates are basedon the results from the AASHTO Materials Reference Laboratory Proficiency Sample Program, withtesting conducted by T 27 and ASTM C136. The data are based on the analyses of test results from 65to 233 laboratories that tested 18 pairs of coarse aggregate proficiency test samples, and test resultsfrom 74 to 222 laboratories that tested 17 pairs of fine aggregate proficiency test samples (Samples No.21 through 90). The values in the table are given for different ranges of total percentage of aggregatepassing a sieve.

Table 2—Estimates of Precision

11.

11.1.


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The precision values for Fine Aggregate in Table 2 are based on nominal 500-g test samples. Revisionof ASTM C136 in 1994 permitted the fine aggregate test sample size to be 300 g minimum. Analysis ofresults of testing of 300-g and 500-g test samples from Aggregate Proficiency Test Samples 99 and 100(Samples 99 and 100 were essentially identical) produced the precision values in Table 3, whichindicate only minor differences due to test sample size.

Note 6—The values for Fine Aggregate in Table 2 will be revised to reflect the 300-g test sample sizewhen a sufficient number of Aggregate Proficiency Tests have been conducted using that sample size toprovide reliable data.

Table 3—Precision Data for 300-g and 500-g Fine Aggregate Test Samples


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1 Similar but not identical to ASTM C136-06.

2 Minor editorial revisions have been made at the discretion of the authors responsible for standards on aggregatematerials (technical section 1c).

Bias—Because there is no accepted reference material suitable for determining the bias in this testmethod, no statement on bias is made.

KEYWORDS

Aggregate gradation; fineness modulus.

12.

12.1.


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Standard Method of Test for Theoretical Maximum Specific Gravity( ) and Density of Hot Mix Asphalt (HMA)

AASHTO Designation: T 209-12 (2016)1


SCOPE

This test method covers the determination of the theoretical maximum specific gravity/gravity mixmaximum (Gmm) and density of uncompacted hot mix asphalt (HMA) at 25°C (77°F).

Note 1—The precision of the method is best when the procedure is performed on samples that containaggregates that are completely coated. In order to assure complete coating, it is desirable to performthe method on samples that are close to the optimum asphalt binder content.


This standard may involve hazardous materials, operations, and equipment. This standard does notpurport to address all of the safety concerns, if any, associated with its use. It is the responsibility ofthe user of this standard to establish appropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.

1.

1.1.

1.2.

1.3.


AASHTO Standards:

M 231, Weighing Devices Used in the Testing of MaterialsR 47, Reducing Samples of Hot Mix Asphalt (HMA) to Testing SizeR 61, Establishing Requirements for Equipment Calibrations, Standardizations, and ChecksT 168, Sampling Bituminous Paving Mixtures

ASTM Standards:

C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods forConstruction MaterialsD4311/D4311M, Standard Practice for Determining Asphalt Volume Correction to a Base Temperature

2.

2.1.

2.2.

TERMINOLOGY

Definitions:

density, as determined by this test method—the mass of a cubic meter of the material at 25°C (77°F) inSI units, or the mass of a cubic foot of the material at 25°C (77°F) in inch-pound units.

residual pressure, as employed by this test method—the pressure in a vacuum vessel when vacuum isapplied.

specific gravity, as determined by this test method—the ratio of a given mass of material at 25°C(77°F) to the mass of an equal volume of water at the same temperature.

3.

3.1.

3.1.1.

3.1.2.

3.1.3.

Standard Method of Test for Theoretical Maximum Specific Gravity (G... http://hm.digital.transportation.org/HM/Part_II_Tests/Bituminous_Materi...

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SUMMARY OF TEST METHOD

A weighed sample of oven-dry HMA in the loose condition is placed in a tared vacuum container.Sufficient water at a temperature of 25 ± 0.5°C (77 ± 0.9°F) is added to completely submerge thesample. Vacuum is applied for 15 ± 2 min to gradually reduce the residual pressure in the vacuumcontainer to 3.7 ± 0.3 kPa (27.5 ± 2.5 mmHg). At the end of the vacuum period, the vacuum isgradually released. The volume of the HMA sample is obtained either by immersing the vacuumcontainer with the sample into a water bath and determining the mass (Section 13.1) or by filling thevacuum container level full of water and determining the mass in air (Section 13.2). At the time ofweighing, the temperature is measured as well as the mass. From the mass and volume measurements,the specific gravity or density at 25°C (77°F) is calculated. If the temperature employed is differentthan 25°C (77°F), an appropriate correction is applied.

4.

4.1.


The theoretical maximum specific gravities and densities of HMA are intrinsic properties whose valuesare influenced by the composition of the mixtures in terms of types and amounts of aggregates andasphalt materials.

These properties are used to calculate percent air voids in compacted HMA.

These properties provide target values for the compaction of HMA.

These properties are essential when calculating the amount of asphalt binder absorbed by the internalporosity of the individual aggregate particles in HMA.

5.

5.1.

5.1.1.

5.1.2.

5.1.3.

APPARATUS

Follow the procedures for performing equipment calibrations, standardizations, and checks found in R61.

Vacuum Container:

The vacuum containers described must be capable of withstanding the full vacuum applied, and eachmust be equipped with the fittings and other accessories required by the test procedure beingemployed. The opening in the container leading to the vacuum pump shall be covered by a piece of0.075-mm (No. 200) wire mesh to minimize the loss of fine material.

The capacity of the vacuum container should be between 2000 and 10 000 mL and depends on theminimum sample size requirements given in Section 7.2. Avoid using a small sample in a largecontainer.

Vacuum Bowl—Either a metal or plastic bowl with a diameter of approximately 180 to 260 mm (7 to 10in.) and a bowl height of at least 160 mm (6.3 in.) equipped with a transparent cover fitted with arubber gasket and a connection for the vacuum line.

Vacuum Flask for Mass Determination in Air Only (Section 13.2)—A thick-walled volumetric glass flaskand a rubber stopper with a connection for the vacuum line.

Pycnometer for Mass Determination in Air Only—A glass, metal, or plastic pycnometer.

Balance—A balance conforming to the requirements of M 231, Class G 2. The balance shall bestandardized at least every 12 months.

6.

6.1.

6.2.

6.2.1.

6.2.2.

6.2.3.

6.2.4.

6.2.5.

6.3.

6.3.1.


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For the mass determination-in-water method (Section 13.1), the balance shall be equipped with asuitable apparatus and holder to permit determining the mass of the sample while suspended below thebalance. The wire suspending the holder shall be the smallest practical size to minimize any possibleeffects of a variable immersed length.

Vacuum Pump or Water Aspirator—Capable of evacuating air from the vacuum container to a residualpressure of 4.0 kPa (30 mmHg).

When a vacuum pump is used, a suitable trap of one or more filter flasks, or equivalent, shall beinstalled between the vacuum vessel and vacuum source to reduce the amount of water vapor enteringthe vacuum pump.

Vacuum Measurement Device—Residual pressure manometer2 or vacuum gauge to be connecteddirectly to the vacuum vessel and capable of measuring residual pressure down to 4.0 kPa (30 mmHg)or less (preferably to zero). The gauge shall be standardized at least annually and be accurate to 0.1kPa (1 mmHg). It shall be connected at the end of the vacuum line using an appropriate tube andeither a “T” connector on the top of the vessel or a separate opening (from the vacuum line) in the topof the vessel to attach the hose. To avoid damage, the manometer shall not be situated on top of thevessel.

Note 2—A residual pressure of 4.0 kPa (30 mmHg) absolute pressure is approximately equivalent to a97 kPa (730 mmHg) reading on a vacuum gauge at sea level.

Note 3—Residual pressure in the vacuum container, measured in millimeters of mercury, is thedifference in the height of mercury in the Torricellian vacuum leg of the manometer and the height ofmercury in the other leg of the manometer that is attached to the vacuum container.

Note 4—An example of a correct arrangement of the testing equipment is shown in Figure 1. In thefigure, the purpose of the train of small filter flasks is to trap water vapor from the vacuum containerthat otherwise would enter the oil in the vacuum pump and decrease the pump’s ability to provideadequate vacuum. Insertion of a valve to isolate the line to each vacuum chamber can reduce wear onthe bleeder valve atop each chamber and assist in tracing sealing leaks.

Figure 1—Example of Correct Arrangement of Testing Apparatus

Bleeder Valve—attached to the vacuum train to facilitate adjustment of the vacuum being applied to thevacuum container.

Thermometric Device (Mass Determination in Air)—A liquid-in-glass thermometer or other thermometricdevice, accurate to 0.5°C (1°F), of suitable range with subdivisions of 0.5°C (1°F). The thermometricdevice shall be standardized at the test temperature at least every 12 months.


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Water Bath:

For vacuum bowls, a water bath capable of maintaining a constant temperature between 20 and 30°C(68 and 86°F) is required. [See Appendix X1 for a method for correcting the theoretical maximumspecific gravity to 25°C (77°F) when measurements are made at temperatures other than 25°C (77°F)].

Thermometric Device (Mass Determination in Water)—A liquid-in-glass thermometer or otherthermometric device, accurate to 0.5°C (1°F) shall be used to measure the temperature of the waterbath. The thermometric device shall be standardized at least every 12 months.

When using the mass determination-in-water technique (Section 13.1), the water bath must be suitablefor immersion of the suspended container with its deaerated sample.

Drying Oven—A thermostatically controlled drying oven capable of maintaining a temperature of 135 ±5°C (275 ± 9°F) or 105 ± 5°C (221 ± 9°F).

Thermometric Device—A liquid-in-glass thermometer or other thermometric device accurate to 3°C(5°F) shall be used to measure the temperature of the oven. The thermometric device shall bestandardized at least every 12 months.

Protective Gloves—Used when handling glass equipment under vacuum.

SAMPLING

The size of the sample shall conform to the following requirements. Samples larger than the capacity ofthe container may be tested a portion at a time.

Table 1—Minimum Sample Sizes

7.

Field samples shall be obtained in accordance with T 168. When necessary, reduce field samples orsamples prepared or produced in a laboratory in accordance with R 47.

7.1.

7.2.

STANDARDIZATION OF FLASKS, BOWLS, AND PYCNOMETERS

For the mass determination-in-water method (Section 13.1), standardize the vacuum bowls fortemperature correction by determining the mass of each container when immersed in water over therange of water bath temperatures likely to be encountered in service (Figure 2).

8.

8.1.


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Figure 2—Example Standardization Curve for Volumetric Flask

For the mass determination-in-air method (Section 13.2), standardize the volumetric flasks or


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pycnometers for temperature correction by determining the mass of the container when filled withwater over the range of water bath temperatures likely to be encountered in service (Figure 3). Whenstandardized at 25 ± 0.5°C (77 ± 0.9°F), designate this mass as D. Accurate filling may be ensured bythe use of a glass cover plate.

Figure 3—Example Standardization Curve for Pycnometer

Standardize the large-size plastic pycnometer by accurately determining the mass of water required tofill it over a temperature range from about 20 to 65°C (70 to 150°F), and construct a standardizationcurve of mass versus temperature as shown in Figure 3. Care should be taken to follow exactly thesame procedure in standardization as in conducting a test.

For models with a quick-disconnect vacuum line and unlatched lid, the filling procedure is as follows:With the inlet valve closed, apply a vacuum of about 30 kPa (225 mmHg). Open the inlet valve slowly,letting water in until the level reaches 25 mm (1 in.) below the top of the dome and close the valve.

The following filling procedure may be used for the model with a latched lid and vented stopper: Thedomed lid is latched in place and the pycnometer nearly filled with water. Leave about 50 mm (2 in.)empty. The release of air bubbles may be facilitated by applying vacuum and by dropping first one sidethen the other of the pycnometer about 10 mm (1/2 in.) above a hard, flat surface. This vacuumapplication and bubble release procedure should take about 10 min so that the temperature equilibriumbetween the shell and the water approximates that attained when performing a test. The final amountof water is then gently poured in until the level is about halfway up the neck. Any air bubbles caughtagainst the dome that cannot be released by jarring or by swirling the water may be “pricked” orpushed to the surface with a bent wire or other suitable device. Insert the vented stopper using onlyenough force to just seat the stopper and immediately wipe the excess water off the top.

8.3.1.


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Continue applying vacuum and release the bubbles by jarring and rapping the vessel with a rubbermallet. Slowly open the inlet valve and allow more water in until the water overflows into the aspirator(vacuum) line and then close the valve. This vacuum application and bubble release procedure shouldtake about 10 min so that the temperature equilibrium between the shell and the water approximatesthat attained when performing a test. Disconnect the vacuum line by pulling it out at the quick-disconnect joint below the gauge.

Wipe the outside of the pycnometer dry, determine the mass of the full pycnometer, and measure thewater temperature.

Note 5—The shape of the standardization curve is a function of two opposing factors that can berationally defined. As the temperature is increased, the container itself expands (addingmass—“Pycnometer” line in Figure 4) and the density of the contained water decreases (resulting inloss of mass—“Water” line in Figure 4). These relationships are shown in Figure 4 for a typical large-sizepycnometer. The “Water” curve may be constructed by multiplying the volume at 25°C (77°F) by thedifference between the density of water at 25°C (77°F), which is 0.9970, and the density of water atthe standardization temperature (see Equation 1).

Figure 4—Effect of Change in Density of Water and Volume of Pycnometer with Change in Temperature

difference due to water expansion = V25 (0.9970 - dw)

Since V25 = W25/0.9970,


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(1)

where:

V25 = volume of water to fill a container at 25°C (77°F), cm3;

W25 = mass of water to fill a container at 25°C (77°F), g; and

dw = density of water at the standardization temperature, Mg/m3.

The rate of change in capacity of the container due to thermal expansion of the pycnometer itself isessentially constant over the temperature range from 20 to 65°C (70 to 150°F). Thus, the “Pycnometer”line in Figure 4 can be drawn through the 0 at 25°C (77°F) point knowing only the slope of the straightline relationship. The slope can be established by averaging at least five standardization massdeterminations at some elevated temperature, adding the loss due to water expansion and subtractingthe mass at 25°C (77°F), W25, to give the gain in capacity due to expansion of the container. Thedifference in mass divided by the difference in temperature is the slope of the “Pycnometer” line. For apolycarbonate pycnometer of about 13, 500-mL capacity, the slope thus established was 2.75 g/°C(1.53 g/°F). This value is believed to be typical and reasonably constant.

The bending of the standardization curve (Figure 3) due to these offsetting thermal factors thusminimizes experimental error due to temperature effects in the normal working range, 25°C (77°F), forboth the volumetric flask and the pycnometer containers. Defining the standardization curve makes itpossible to correct for temperature, rather than “bringing the container and sample to temperature,”thereby eliminating the cost of a water bath and making it feasible to improve accuracy by testinglarger samples and to materially reduce the testing time.

While standardization of the flask or either pycnometer needs to be performed only once, thestandardization should be checked occasionally, particularly at 25°C (77°F). The equipment must bekept clean and free from any accumulation that would change the mass if the volume standardization isto remain constant. Care should be taken to use only neutral solvents, especially with plastic containers;glass vessels should not be subjected to high vacuum if they are scratched or damaged.

SAMPLE PREPARATION

Separate the particles of the HMA sample by hand, taking care to avoid fracturing the aggregate, sothat the particles of the fine aggregate portion are not larger than 6.3 mm (1/4 in.). If an HMA sample isnot sufficiently soft to be separated manually, place it in a pan, and warm it in an oven until it can beseparated as described.

Samples prepared in a laboratory shall be conditioned and dried in an oven at 135 ± 5°C (275 ± 9°F)for a minimum of 2 h or as appropriate to match the mix design procedure being used. Longer dryingtime may be necessary for the sample to achieve a constant mass (mass repeats within 0.1 percent).HMA that has not been prepared in a laboratory with oven-dried aggregates shall be dried to a constantmass at a temperature of 105 ± 5°C (221 ± 9°F). This drying and conditioning operation shall becombined with any warming described in Section 9.1.

Note 6—The minimum 2 h time in the oven is specified as the short-term conditioning time for

9.

9.1.

9.2.


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laboratory-prepared specimens. The short-term conditioning at the specified temperature is especiallyimportant when absorptive aggregates are used. This short-term conditioning will ensure thecomputation of realistic values for the amount of asphalt absorbed by the aggregate and void propertiesof the mix. Plant-produced HMA should not be short-term conditioned because absorption takes placeduring production.

Cool the sample to room temperature, and place it in a tared and standardized flask, bowl, orpycnometer. The sample is to be placed directly into a vacuum container. A container within a containeris not to be used. Determine the mass and designate the net mass of the sample as A. Add sufficientwater at a temperature of approximately 25°C (77°F) to cover the sample completely.

Note 7—The release of entrapped air may be facilitated by the addition of a suitable wetting agentsuch as Aerosol OT in concentration of 0.001 percent or 0.2 g in 20 L of water. This solution is thendiluted by about 20:1 to make a wetting agent of which 5 to 10 mL may be added to the apparatus.

TEST METHOD A—MECHANICAL AGITATION

APPARATUS

In addition to the apparatus listed in Section 6, the following apparatus is required for Method A:

Mechanical Shaker—Shaker for removing air from asphalt mix.

10.

10.1.

10.1.1.

PROCEDURE

Remove air trapped in the sample by applying gradually increased vacuum until the residual pressuremanometer reads 3.7 ± 0.3 kPa (27.5 ± 2.5 mmHg). Maintain this residual pressure for 15 ± 2 min.Agitate the container and contents using the mechanical device during the vacuum period. Glass vesselsshould be shaken on a resilient surface such as a rubber or plastic mat, and not on a hard surface, soas to avoid excessive impact while under vacuum.

At the end of the vacuum period, release the vacuum by increasing the pressure at a rate not to exceed8 kPa (60 mmHg) per second and proceed with one of the mass determination methods in Section 13.

11.

11.1.

11.2.

TEST METHOD B—MANUAL AGITATION

PROCEDURE

Remove air trapped in the sample by applying gradually increased vacuum until the residual pressuremanometer reads 3.7 ± 0.3 kPa (27.5 ± 2.5 mmHg). Maintain this residual pressure for 15 ± 2 min.Agitate the container and contents during the vacuum period by vigorously shaking at intervals of about2 min. Glass vessels should be shaken on a resilient surface such as a rubber or plastic mat, and not ona hard surface, so as to avoid excessive impact while under vacuum.

At the end of the vacuum period, release the vacuum by increasing the pressure at a rate not to exceed

12.

12.1.

12.2.


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8 kPa (60 mmHg) per second and proceed with one of the mass determination methods in Section 13.

MASS DETERMINATION

Mass Determination in Water—Suspend the container and contents in the water bath and determine themass after a 10 ± 1 min immersion. Measure the water bath temperature, and if different from 25 ±1°C (77 ± 2°F), correct the mass to 25°C (77°F) using the standardization temperature adjustmentdeveloped in Section 8.1. Designate the mass of the sample in water at 25°C (77°F) as C.

Note 8—Instead of using a chart like Figure 2 to establish the mass correction for the temperature ofthe vacuum vessel submerged by itself in the water bath, this correction can be easily established byrapidly and completely emptying the vacuum container immediately following the final massdetermination, and then without delay, determining the mass of the vessel by itself when totallysubmerged in the water bath.

Mass Determination in Air—Fill the flask or any one of the pycnometers with water and adjust thecontents to a temperature of 25 ± 1°C (77 ± 2°F). Determine the mass of the container and contents,completely filled, in accordance with Section 8.2 within 10 ± 1 min after completing Section 11.1 or12.1. Designate this mass as E.

Note 9—See Appendix X1 for correcting the theoretical maximum specific gravity when measurementsare made at temperatures other than 25°C (77°F).

13.

13.1.

13.2.

CALCULATION

Calculate the theoretical maximum specific gravity (Gmm) of the sample at 25°C (77°F) as follows:

Mass Determination in Water:

(2)

where:

A = mass of the oven-dry sample in air, g; and

C = mass of the sample in water at 25°C (77°F), g.

Mass Determination in Air:

(3)

where:

A = mass of the oven-dry sample in air, g;

14.

14.1.

14.1.1.

14.1.2.


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D = mass of the container filled with water at 25°C (77°F), g; and

E = mass of the container filled with the sample and water at 25°C (77°F), g.

Large-Size Plastic Pycnometer Determinations:

If the test temperature is between 22.2 and 26.7°C (72 and 80°F), Equation 3 may be used to calculatespecific gravity (Gmm) within a minor amount of error due to thermal effects (0.001 points or less).

If the test temperature differs significantly from 25°C (77°F), correct for thermal effects as follows:

(4)

where:

A = mass of the oven-dry sample in air, g;

F = mass of the pycnometer filled with water at the test temperature (Figure 3), g;

G = mass of the pycnometer filled with water and the sample at the test temperature, g;

H = correction for thermal expansion of asphalt (Figure 5), g;

dw = density of water at the test temperature, Curve D in Figure 6, Mg/m3; and

0.9970 = density of water at 25°C (77°F), Mg/m3.

The ratio (dw/0.9970) is Curve R in Figure 6.


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Figure 5—Correction Curves for Expansion of Asphalt, H, in Equation 4


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Figure 6—Curves D and R for Equation 4

Note 10—This general procedure for correcting for thermal effects should also be applicable tocorresponding measurements made with other suitable containers.

Note 11—When samples are tested a portion at a time, differences between the maximum specificgravities for each portion should be within the precision statements listed in Section 17. If the valuesare within the precision statements, the specific gravities for each portion shall be averaged. If thevalues are outside the precision statements, the test shall be performed again.

Theoretical maximum density (Gmm) at 25°C (77°F):

Calculate the corresponding theoretical maximum density (Gmm) at 25°C (77°F) as follows:

Theoretical maximum density at 25°C (77°F) = theoretical maximum specific gravity × 997.1 kg/m3 inSI units.

or

Theoretical maximum density at 25°C (77°F) = theoretical maximum specific gravity × 62.245 lb/ft3 ininch-pound units.

where:

The density of water at 25°C (77°F) = 997.1 kg/m3 in SI units or 62.245 lb/ft3 in inch-pound units.


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SUPPLEMENTAL PROCEDURE FOR MIXTURES CONTAINING POROUSAGGREGATE

Note 12—Experiments indicate that this supplemental procedure has an insignificant effect on the testresults if the HMA contains individual aggregate with a water absorption below 1.5 percent.

If the pores of the aggregates are not thoroughly sealed by an asphalt film, they may become saturatedwith water during the application of vacuum. To determine if this condition has occurred, proceed asfollows after completing Section 13.1 or 13.2. Drain the water from the sample. To prevent the loss offine particles, decant the water through a towel held over the top of the container. Break several largepieces of aggregate and examine the broken surfaces for wetness.

If the aggregate has absorbed water, spread the sample before an electric fan to remove the surfacemoisture. Determine the mass at 15-min intervals, and when the loss in mass is less than 0.05 percentfor this interval, the sample may be considered to be surface dry. This procedure requires about 2 hand shall be accompanied by intermittent stirring of the sample. Break conglomerations of HMA byhand. Take care to prevent loss of the HMA particles.

To calculate the specific gravity of the sample, substitute the final surface-dry mass determined inSection 15.2 for A in the denominator of Equation 2 or 3 as appropriate.

15.

15.1.

15.2.

15.3.

REPORT

Report the following information:

Gmm and density of the HMA to the nearest 0.001 for specific gravity or nearest 1 kg/m3 (0.1 lb/ft3) fordensity as follows: sp gr 25/25°C (77/77°F) or density at 25°C (77°F);

Type of HMA;

Size of the sample;

Number of samples;

Type of container; and

Type of procedure.

16.

16.1.

16.1.1.

16.1.2.

16.1.3.

16.1.4.

16.1.5.

16.1.6.

PRECISION

Criteria for judging the acceptability of specific gravity test results obtained by this test method aregiven in the following table:

Table 2—Precision Estimates

17.

17.1.


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The figures given in Column 2 are the standard deviations that have been found to be appropriate forthe conditions of the test described in Column 1. The figures given in Column 3 are the limits thatshould not be exceeded by the difference between the results of two properly conducted tests.Multilaboratory precision has not been verified for 4500-mL or larger pycnometers.

The values in Column 3 are the acceptable range for two tests. When more than two results are beingevaluated, the range given in Column 3 must be increased. Multiply the standard deviation(s) in Column2 by the multiplier given in Table 1 of ASTM C670 for the number of actual tests.

Example for three tests: 0.004 × 3.3 = 0.013.

Additional guidance and background is given in ASTM C670.

KEYWORDS

Agitation; asphalt mixture; hot mix asphalt; maximum density; maximum specific gravity;pycnometer;vacuum.

18.

18.1.

APPENDIX(Nonmandatory Information)

THEORETICAL MAXIMUM SPECIFIC GRAVITY FOR LOOSE HMA

Scope:

This appendix has two objectives:

To indicate a method for correcting the theoretical maximum specific gravity to 25°C (77°F) whenmeasurements are made at temperatures other than 25°C (77°F).

To indicate the range of temperature in °C above or below 25°C (77°F) within which no temperaturecorrection is required, because the measured theoretical maximum specific gravity values are shown tobe 0.0004 or less away from the value determined at 25°C (77°F).

Indicated Values:

X1.

X1.1.

X1.1.1.

X1.1.1.1.

X1.1.1.2.

X1.2.


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The following example values are indicated for the theoretical maximum specific gravity of a loose HMAsample:

Mass of the loose HMA sample = 1251.3 g.

Volume of the loose HMA sample at 25°C (77°F) = 492.77 mL.

Asphalt binder content = 5.0 percent of total mix.

Specific gravity of the asphalt at 25°C (77°F) = 1.029.

Combined bulk specific gravity of the aggregate = 2.714.

Cubical coefficient of expansion of the asphalt binder at 20°C (68°F) = 6.2 × 10–4 mL/mL/°C (ASTMD4311/D4311M).

Cubical coefficient of expansion of the aggregate at 20°C (68°F) = 2.2 × 10–5 mL/mL/°C.3

Basis of Calculation for 1 g of Loose HMA at 20°C (68°F):

Mass of the asphalt binder = 0.05 g.

Volume of the asphalt binder = 0.05/1.029 = 0.0486 mL.

Mass of the aggregate = 0.95 g.

Volume of the aggregate = 0.95/ 2.714 = 0.3500 mL.

Volume of the asphalt binder plus aggregate in 1 g of loose HMA at 20°C (68°F) = 0.0486 + 0.3500 =0.3986 mL.

Basis of Calculation for Volume Change of 1 g of Loose HMA for1°C (2°F) from 20°C (68°F):

Volume change for the asphalt binder = 6.2 × 10–4 × 0.0486 = 0.3013 × 10–4 mL = 3.0130 × 10–5 mL.

Volume change for the aggregate = 2.2 × 10–5 × 0.3500 = 0.77 × 10–5 mL.

Volume change for 1 g of loose HMA for 1°C (2°F) change in temperature from 20°C (68°F) = 3.0130 ×10–5 + 0.7700 × 10–5 = 3.7830 × 10–5 mL.

Volume Correction:

For a difference in water temperature of 1°C (2°F) above or below 20°C (68°F), a correction to thevolume of water displaced by 1 g of loose HMA can be made by the following equation:

(X1.1)

where:

ΔT = 1°C (2°F);

KT = volume change of 1 g of loose HMA for a 1°C (2°F) change in temperature above or below20°C (68°F) = 3.7830 × 10–5 mL; and

VT = volume of water for a corresponding 1251.3-g mass of loose HMA at a test temperature of20°C (68°F) = 492.77 mL.


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Substituting these values into the equation gives the following:

Correction = 1 × 3.7830 × 10–5 × 492.77 = 0.01864 mL/g at 20°C (68°F).

Table X1.1 illustrates an example of the influence of temperature corrections. For a measured volumeand a given mass of HMA tested at specific temperatures, this table relates these influences to thespecific gravity of the HMA.

Table X1.1—Influence of Temperature Corrections to a Measured Volume at 20°C of a Given Mass of Loose PavingMixture, to Provide the Required Theoretical Maximum Specific Gravity at 25°C

1 Reapproved with no technical changes; minor editorial revisions have been made at the discretion of the authorsresponsible for standards on Asphalt–Aggregate Mixtures (technical section 2c).

2 Sargent Welch, 39745 Gauge-Vacuum, Mercury Prefilled (or equivalent).

3 Krebs and Walker, Highway Materials, McGraw-Hill, Inc., 1971, p. 274.


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