civil engineering department - philadelphia university

Highway Laboratory-1st semester 2020/2021

1

Philadelphia University

Faculty of Engineering Civil Engineering Department

Highway Laboratory Manual

كراسة التجارب المختبرية

مختبر الطرق

Prepared by

Lab Instructor : Eng. Sahar Al-Mutairi

Reviewed by

Eng. Amani Al-assouli


2

Introduction:


3

فحوصات الأسفلت

تجربة(1رقم)

الإختراق أو الغرز للبيتومين


4

Objectives The penetration test is used to measure consistency of bituminous materials expressed as the distance in tenth millimeter (1/10 mm) that a standard needle vertically penetrates a sample of the material under known conditions of loading, loading time and temperature.

Main Principle

A needle of specified dimensions is allowed to penetrate vertically into a bituminous material under specified load, temperature and time conditions. The distance the needle penetrates in units of 1/10 mm is termed the penetration value. This method is valid for penetration values in the range 2-500.

Apparatus 1- Penetration device (penetrometer) 2- Standard penetration needle 3- Water path 4- Stop watch 5- Penetration tins

Procedure

Step1: Heat the sample carefully.

The heating and pouring should be accomplished within a period of 30 minutes.

Step2: Pour the sample into penetration tin. Immediately after pouring the sample, the tin must

be covered to protect from dust.

Step3: The sample is then allowed to cool off at room temperature for (1-1.5) hours.

Step4: After cooling transfer it to the water bath at a temperature of 25 c for (1.5 – 2) hours.

Step5: Place the tin on the stand of the penetrometer.

Step6: Adjust the needle height so that it is just touching the surface of the sample.

Step7: Set the penetrometer dial to zero and then release the needle holder for the specified time

(5 sec).

Step8: Measure the depth of penetration by the needle position.

Step9: Carry out at least 3 determinations at points on the surface at least 1 cm apart, gently

clean the needle after each test.

(Penetration Test Of Bituminous Material)

#1 ASTM D5-97

Penetrometer


5

Test Conditions: 1) Temperature :25 c 2) Loading Time :5 seconds 3) Loading :100 g

Note:

The conditions and procedures described provide for determinations of penetrations up to 350.

However, the method may also be used for direct determinations up to 500.

This will require larger penetration tin and specified needle.

Or we can use the same tin and needle but it‟s necessary to left 50g only and multiplies the dial

gage reading by

Correct penetration on 100g load = x penetration on 50g load.

Table1: (The Grades of the asphalt cement depending on the penetration in 1/10mm)

Asphalt grade Uses

AC 20-30 used for inclined planes due to its high viscosity

(Hard & not effect with temperature)

AC 40-50 used for filling isolation cracks and joints

AC 60-70 used for highway pavement (hot weather)

AC 80-100 AC 120-150

used for highway pavement (cold weather)

AC 200-300 used for emulsions


6

Results

If the deviation between highest and lowest value of the 3 parallel measurements exceeds the

values in table 2, the measurement must be rejected. Repeat the test.

Table2 :( Acceptable differences between 3 parallel measurements)

Penetration, 1/10mm 0-49 50-149 150-249 250-

Max diff. between highest and lowest determination

2 4 6 8

Calculations

When the requirements in table2 are met, calculate the average value to the nearest whole unit

(1/10 mm).

No. Penetrometer reading

(mm) Penetration value

(1/10 mm)

1

2

3

Penetration Value of the sample (1/10 mm) = Average of the three readings.


7

(2رقم) تجربة

نتحديد نقطة الطراوة للبيتومي


8

Softening Point Test

#2

ASTM D36-95

Objectives

Determine the softening point of a bitumen sample using the Ring and Ball Apparatus.

Introduction

Softening point : it‟s the temperature at which bitumen change from solid state to liquid state.

Bitumen does not change from solid state to liquid state at any definite temperature, but gradually

become softer and less viscous as the temperature rises.

Main Principle

A steel ball of 3.5g is placed on a sample of bitumen contained in a

brass ring which suspended in a water bath.

Water is used for softening point of 80 c and below, glycerin is used

for softening points greater than 80 c .

The bath temperature is raised at constant rate 5 c/minute, the

bitumen gradually softens and eventually deforms slowly as the ball

falls through the ring.

At the moment the bitumen and the steel ball touches a base plate

25mm below the ring, the temperature recorded.

Apparatus

1) Ring and Ball Apparatus:

a) brass shouldered ring with a 5/8 in Diameter

b) Steel balls

c) Glass bath

d) Ring holder

e) Thermometer

2) Distilled water


9

Procedure

Step1: Heat the bitumen at 110 c above it‟s expected softening point

Step2: Pour the heated sample in to 2 rings

Step3: Allow the sample to cool in rings for 30min at room temperature

Step4: put two steel balls above rings

For materials have softening points 80 c or below:

Step5: Fill the glass beaker with freshly distilled water

Step6: Put the Apparatus in the water (start the test at 5 c)

Step7: Now start to increase temperature with constant rate 5 c/min

Step8: Record the temperature at which the balls penetrate the sample rings.

For materials have softening points above 80 c:

Follow the same procedure expect use glycerin instead of water and start test at 35 c.

Results

If the softening point for the two parallel samples is differs by more than the following ranges

repeat the test.

Temperature ranges

Difference between two samples

30 c-60 c 1 c

61 c-80 c 1.5 c

Now,Report the average temperature of two recorded softening points to the nearest 0.5 c


10

(3تجربة رقم )

للبيتومين لمرونة أو الممطوليةا


11

Ductility Test

#3 ASTM D113-99

Objectives The Ductility test is used to describe the ductile and tensile behavior of bituminousbinders.

Introduction Ductility: is the distance in cm a standard sample of asphalt material will stretch before breaking

when tested on standard ductility test equipment at 25 .

The result of this test indicates the extent to which the material can be deformed without

breaking. This is an important characteristic for asphalt materials, although the exact value of

ductility is not as important as the existence or nonexistence of the property of the material.

Main Principle

Bitumen sample must first heat gently to facilitate flow and then poured into a standard mold to

form a briquette.

The sample then is allowed to cool to 25 in a water bath.

The prepared sample is placed in the ductility machine and extended at a specified rate of speed

5cm/min until it breaks.

The distance in cm moved by the machine is reported as the ductility of the material.

Apparatus

1) Ductilometer (Ductility Device)

2) Ductility mold

3) Water bath

4) Thermometer

Procedure

Step1: Heat the bitumen carefully.


12

Step2: Pour the heated bitumen into molds.

Step3: Cool it at room temperature for (30-40) minute.

Step4: Place the molds in the water bath at the specified testing temperature 25 c. leave it in

the water bath for 30 minute.

Step5: Remove the samples from the bath and cut of the excess bitumen with hot straight edged

knife to make the mold just level full.

Step6: After storage in the water bath, remove the brass plate and sidepieces. Immediately place

the samples in the testing machine.

Step7: Start pulling the sample at speed of 5cm/minute.

Step8: Record the distance in cm at which the bitumen breaks.

Results

Record the ductility distance in cm, and check if this distance is 100 cm.

Notes

1) Coating of aggregate is better with high ductility material so the binder will be better.

2) If the Bitumen in the test was sagging down the material has higher density than water so we

rise water density by adding (salt) and if the bitumen was floating its density less than water

density so we decrease water density by adding alcohol.


13


للبيتومين الإحتراق و تحديد نقطة الوميض


14

Flash and Fire Point Test

#4 ASTM D92-Ib36

Objectives

1) Determine the Flash and Fire Points of bitumen sample using Cleveland Open Cup Apparatus. 2) Determine the temperature to which bitumen maybe safely heated without danger.

Introduction

Flash Point: is the lowest temperature at which the vapor from the liquid is ignited by an open

flame.

It's the temperature at which the vapor pressure is high enough to give off sufficient hydrocarbon

vapors to form an explosive mixture with air when contacted with an open flame.

Fire Point: the temperature at which the material will burn for at least 5 seconds.

Main Principle

The test cup is filled to a specific level. The sample is heated at specified rate. At specified

intervals, a small flame is passed over the sample. The lowest temperature that causes the vapors

to ignite is taken as the flash point. When determining the fire point, the test is continued until the

test flame causes the sample to ignite and burn for at least 5 seconds.

This method is used to determine the flash and fire points of all petroleum products, except fuel

oils and those having an open cup flash below 79 .

In British Standards, the expected Flash Points are as followed:

Type of Bitumen Flash Point

Asphalt Cement (AC) 175 -235

Cutback Asphalt

SC >110

MC 110 -40

RC <40

For AC and SC cutback, the sample is heated at a high rate of 14-17 /min. When we reach 56

below the expected flash point we reduce the rate to 5-6 /min and we start passing the flame at

28 below the expected Flash Point.

For RC and MC this is impossible to heat it at a high rate, because the sample will burn within 2-

3min, so we start at a low rate.

The Cleveland open Cup Flash Point tester is widely used. The material in the cup is directly

heated by a Bunsen burner with the temperature rising at a slow constant rate. A small test flame

is passed across the cup at specified intervals. The lowest temperature at which application of the

test flame causes vapors above the surface of the liquid to ignite is taken as Flash Point. If the


15

Flash Point test is continued until the test flame causes the liquid to ignite and burn for at least

5sec then this temperature is taken as Fire Point.

Apparatus

The apparatus shall consist of the following:

1- Cleveland Open Cup apparatus, this consists of a test cup, heating plate, test flame applicator,

heater and supports.

2- Thermometer.

Procedure

Step1: Support the apparatus on a level table

Step2: Wash the test cup with an appropriate solvent to remove any oil or traces of gum or residue

remaining from a previous test.

Step3: Support the thermometer in a vertical position with the bottom of the bulb 6.4 mm from

the bottom of the cup and located at a point halfway between the center and side of the

cup on the diameter perpendicular to the line of the sweep of the test flame and on the

side opposite to the test flame burner arm.

Step4: Fill the cup to the filling line; at any convenient temperature not exceeding 100 °C or

above the softening point.

Step5: Lit the test flame and adjust it to a diameter of 3.8 to 5.4 mm. The center of the flame

should be maximum 2 mm above the edge of the test cup.

Step6: Apply heat and adjust the temperature rise of the sample to (14-17) /min. When the

temperature of the sample is 56 below the expected flash point, decrease the heat to a

temperature rise of (5-6) /min. This constant temperature rise should be attained during

last 28 before the flash point.

Step7: Starring at minimum 28 below the flash point, apply one sweep of the test flame for

every 2 rise on the thermometer (in opposite direction each time).

Step8: The flash point is recorded as the reading on the thermometer when the first flash appears

on the sample surface.

Step9: To determine the fire point, continue heating at the specified rate of (5-6) /min and

apply the test flame for each 2 rise in the temperature. The fire point is recorded as the

thermometer reading when the sample ignite and continuous to burn for at least 5 seconds.


16

Results and Calculations

When the Pressure in testing room differs from 760 mm Hg ( the atmospheric pressure at sea level)

correct the flash and fire point by the following equation, because the Atmospheric Pressure will

affect the vaporizing rate and so the Flash Point.

Corrected of Flash/Fire Point = C° + 0.03 (760 - P)

Where:

C°: Observed Fire\Flash Point

P: Pressure in testing room

760: 760mm Hg, the atmospheric pressure at sea level


17

Asphalt Binder Tests

Experiment #5

Say bolt Viscometer Test Of Petroleum

Products

تجربة(5رقم)

فحص اللزوجة للمواد البترولية


18

(Say bolt Viscometer Test Of Petroleum Products)

#5

ASTM D88-99 :

Objectives To determine viscosity of the given oil using saybolt viscometer at different temperatures expressed in terms of saybolt seconds.

Empirical procedure for determining saybolt viscosity of petroleum products at specified temperature (21-99) oC.

Main Principle

Viscosity • The device used for measurement of viscosity is known as viscometer . The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress, The units of viscosity is poise and centipoise. A device used to measure the viscosity of a fluid. The saybolt viscometer controls the heat of the fluid and the viscosity is the time is takes the fluid to fill a container, Efflux cup viscometers are most commonly used for fieldwork to measure the viscosity of oils, syrups, varnish, paints and Bitumen emulsions. Efflux time of a specified volume of fluid is measured through fixed orifice at the bottom of a cup to represent the viscosity of the fluid There are three types of orifices available-Universal, Furol, Asphalt orifice. The furol and asphalt orifices, respectively, have an efflux time of approximately, one-tenth and one-hundredth that of the universal orifice. Saybolt viscosity - Efflux time in seconds of 60 ml. of sample flowing through a calibrated orifice under specified condition. a.Saybolt Universal Viscosity “SUV” Determined using an orifice of (1.76 ± 0.015) mm in diameter used for lubricants and distillates with efflux time greater than 32 sec. and less than 1000 sec. The viscosity value is reported in Saybolt Universal seconds, abbreviated SUS, at a specified temperature. b.Saybolt Furol Viscosity “SFV” Determined using an orifice of (3.15 ± 0.02) mm in diameter used when “SUV” value is greater than 1000 sec. The viscosity value is reported in Say bolt Furol seconds, abbreviated SFS, at a specified temperature. The “SFV” is approximately one tenth the “SUV”.

Apparatus 1- Saybolt viscometer apparatus. 2- Thermometer. 3- Stop watch. 4- Receiving Flask 60 ml.


19

Figure (5-2) Saybolt viscometer with universal and furol orifice

Figure (5-3) Receiving flask


20

Preparation of Apparatus: 1. Clean viscometer and receiving flask thoroughly with appropriate solvent. 2. Place the receiving flask beneath the viscometer so that the graduation mark on the flask is from (100-130) mm. below the bottom of the viscometer tube. 3. Fill the bath to at least 6 mm. above the over flow rim of the viscometer, the bath media used is water or oil for test temperature less than 98 OC and oil for higher test temperature. Procedure 1. Establish and control bath temperature. 2. Insert a cork stopper at the bottom of the viscometer. 3. Preheat the sample to not more than 1.7oC above test temperature, and 28 oC of its flash point. 4. Stir the sample and strain it through sieve No. 100 directly into the viscometer. 5. Stir the sample in the viscometer with the thermometer, use a circular motion at (30to 50) rpm in a horizontal plane. Remove thermometer when the temperature remains constant within 0.03OC of the test temperature during one minute of continuous stirring. 6. Place the tip of the withdrawal tube in the gallery at a point and apply suction to remove oil until its level in the gallery is below the over flow rim. 7. Place the receiving flask in its proper position. 8. Snap the cork and start the timer. 9. Stop the timer the instant the bottom of the oil meniscus reaches graduation mark. 10.Record the efflux timer in seconds to the nearest 0.1 sec. This will be theviscosity.

Note: v = m2/s 1.0 m2/s = 10000 Stokes = 1000000 Centistokes (cSt) 1 mm2/sec= 1 cSt 1 mPa.s = 0.001 Pa.s Kinematic Viscosity = Dynamic Viscosity / Density v = ì / p Centistokes = Centipoise / Density To understand the metric units involved in this relationship it will be necessary to use an example: Dynamic viscosity ì = Pa•s Substitute for Pa = N/m2 and N = kg• m/s2 Therefore ì = Pa•s = kg/(m•s) Density p = kg/m3 Kinematic Viscosity = v = µ/p = (kg/(m•s) x 10-3) / (kg/m3) = m2/s x 10-6

Results

1. Report the time in seconds to the nearest 0.1 sec. and the test temperature inᵒC. 2. To draw the relationship between viscosity and temperature, arrange a table contains (temperature and efflux time) as follows:-

Test number Temperature ᵒC Efflux time (viscosity)

sec.


21

Calculations

Saybolt universal seconds (t) can be converted to kinematic viscosity (v) by the following equations:

When t < 100 secs, v = 0.226t - 195/t Centistokes When t >100 secs, v = 0.220t - 135/t Centistokes Where: v = viscosity in centistokes, t = viscosity in SUS.

Draw the necessary relationship for this test?

Determine the Theo. And exp. value for viscosity and errors?

Type of oil:

Trial

No.

T (oC) eiiT xulffE [VFS,VUS] cftEfenfK

Viscosity

(KVn)

Dynamic

SfcKocfnV(mPa.s)

(fft) (cEK)

Discussion:

1. Importance of Saybolt viscosity test. 2. What is the effect of temperature on viscosity? 3. What is used in the bath media of viscosity test? Why? 4. Set another method to determine the viscosity. 5. What is the theoretical meaning of viscosity of material? 6. What is the relation between penetration and viscosity? Explain that.


22

تجارب الحصمى


إختبار التآكل أو البري للمواد الخشنة


23

Los Angeles Abrasion Test

#6 ASTM C131-96

Objectives

Measuring the hardness of coarse aggregate, i.e. the resistance of wear using Los Angeles method

to determine the Los Angeles Abrasion Value (L.A.A.V).

Introduction

Aggregates undergo substantial wear and tear throughout their life. In general, they should be hard

and tough enough to resist crushing, degradation and disintegration from any associated activities

including manufacturing, stockpiling, production, placing and compaction. Aggregates not

adequately resistant to abrasion and polishing may cause premature structural failure.

Furthermore, poor resistance to abrasion can produce excessive dust during concrete production

resulting in mixture control problems.

Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be

intentionally imposed in a controlled process using an abrasive.

Los Angeles abrasion test studies all possible reasons causing wear. In the L.A. abrasion machine

Attrition, Abrasion, and crushing are all present as follows:

Attrition: By the friction between the aggregate particles. Abrasion: By the friction between the steel balls and the aggregates. Crushing: By hitting the walls of the testing machine.

The Los Angeles (L.A.) abrasion test is a common test method used to indicate aggregate toughness

and abrasion characteristics. Aggregate abrasion characteristics are important because the

constituent aggregate in concrete must resist crushing, degradation and disintegration in order to

produce a high quality concrete.

The standard L.A. abrasion test subjects an aggregate sample to abrasion, impact, and grinding in a

rotating steel drum containing a specified number of steel spheres.

After being subjected to the rotating drum, the weight of aggregate that is retained on a No. 12

(1.70 mm) sieve is subtracted from the original weight to obtain a percentage of the total

aggregate weight that has broken down and passed through the No. 12 (1.70 mm) sieve. Therefore,

an L.A. abrasion loss value of 40 indicates that 40% of the original sample passed through the No.

12 (1.70 mm) sieve.


24

Los Angeles Test Grades Los Angeles abrasion test has four common grades (A, B, C and D). Choosing of the suitable grade depends on the major particle size of the sample; the following table shows these four grades with their correspondent sample particles size and the required weight of each size, in addition to the standard number of spheres required for each grade.

Testing technique The required weight of washed-dried sample is placed inside the Los Angles rotating steel drum containing the specified number of steel spheres. As the drum rotates, a shelf inside the drum picks up the aggregate and steel spheres. The shelf carries them around until they drop on the opposite side of the drum, subjecting the aggregate to impact and crushing. Then, the aggregate is subjected to abrasion and grinding as the drum continues to rotate until the shelf picks up the contents, and the process is repeated. The drum is rotated for 500 revolutions. Afterward, the aggregate is removed from the drum and sieved on a No. 12 (1.70 mm) sieve. The aggregate retained on the sieve is weighed and the difference between this weight and the original weight is expressed as a percentage and reported as the L.A. abrasion loss value.

Procedure

(1) Wash and oven‐dry 5,000 g of aggregate sample [Dry to constant mass at 230 ºF (+/‐9) (110

ºC (+/‐5)).

(2) Separate sample into individual size fractions by sieving.

(3) Recombine the sieved material to the required grading.

(4) Record total mass to nearest 1 g.

(5) Put the sample on the drum with the suitable number of steel balls.

(6) Rotate the drum for 500 revolutions at a constant speed of 30 to 33 rpm (approximately 15

minutes.)

(7) Remove the sample from the machine.

(8) Sieve the crushed sample over a No. 12 sieve.

(9) Weigh the retained mass to nearest 1.

Sample Weight of Indicated Sizes, g

Sieve Size (Square Openings) Grading

Passing Retained on A B C D

37.5 mm (1-1/2 in.) 25.0 mm (1 in.) 1250 +/- 25

25.0 mm (1 in.) 19.0 mm (3/4 in.) 1250 +/- 25

19.0 mm (3/4 in.) 12.5 mm (1/2 in.) 1250 +/- 25 2500 +/- 10

12.5 mm (1/2 in.) 9.5 mm (3/8 in.) 1250 +/- 25 2500 +/- 10

9.5 mm (3/8 in.) 6.3 mm (1/4 in.) 2500 +/- 10

6.3 mm (1/4 in.) 4.75 mm (No. 4) 2500 +/- 10

4.75 mm (No. 4) 2.36 mm (No. 8) 5000 +/- 10

Total 5000 +/- 10 5000 +/- 10 5000 +/- 10 5000 +/- 10

# of Spheres 12 11 8 6


25

Data and Calculations

( )( )

Where


26


إختبار تحديد نسبة تحمل كاليفورنيا


27

California Bearing Ratio Test (CBR)

#7 ASTM D1883-99

Objectives

To determine the California Bearing Ratio (CBR) of a soil sample containing a small amount of

material that passing sieve ¾ inch.

Theory

The test consists of measuring the load required to cause a plunger of standard size to penetrate a

soil specimen at a specified rate (1.27mm/min).

The CBR can be define asthe load required to force a piston into the soil at a certain depth(at

specific density and moisture ), expressed as a percentage of the load required to force the piston

the same depth(at same specific density and moisture ) into a standard sample of crushed stone.

Usually depths of 2.5 mm (0.1 inch) & 5.0 mm (0.2 inch) are used, but depths of up to 12.5 mm can

be used if desired.

This test applied at two samples the first one is dry and the other is soaked.

The test on the soaked sample provides

1) information concerning expected soil expansion beneath the pavement when the soil becomes

saturated.

2) an indication of strength loss from field saturation.

Apparatus

There are two test have some different tools:

First Test: dry sample

CBR mold

Spacer disc

Compaction Hummer (4.5 Kg)

¾ in sieve & No.4

Surcharge weights

Apparatus for measuring the load on the piston and the movement of the piston during

penetration

A jack for applying load to the piston

Coarse filter paper


28

Second Test: soaked sample

Compaction Hammer

CBR mold body

Extension collar

Solid base for mold

Tool for base plate

Surcharge weight

Spanner ( to mount and dismount collar from mold )

Perforated plate with adjustable stem

Spilt surcharge weight

Compaction plug with handle

Swell dial gauge

Socking tank


29

Procedure Step1: Select 5Kg soil sample that passing sieve ¾ inch.

Step2: The sample should have 20% weight of sample as water, dry the sample at 110c by oven for

one day then add 1000g water.

Step3: Clamp the mold to the base plate, insert the spacer disc in the mold and cover with a piece

of filter paper

Step4: Compact the sample in 5 layers by 56 blows per layer of the 4.5Kg hummer.

Step5: Remove the extension ring and strike off excess soil with a straight edge.

Step6: Place a piece of filter paper on the base plate, invert the specimen (so the spacer gap is on

top) and attach the base plate so the soil is in contact with the filter paper on the base.

Step7: Place annular surcharge disc on the soil surface to simulate the required overburden

pressure.(should not be less than 4.5Kg).Be sure this mass is the same as will be surcharge

during soaking of the second sample

Step8: Place the specimen in the compression machine, set the load dial to zero also zero the

penetration dial.

Step9: Apply the load to the piston at a uniform rate of 1.27mm/min of penetration. Note the load

readings for every o.5mm of penetration until 7.5mm penetration.

For soaked sample:

Step1: Repeat steps 1-6

Step2: Place a filter paper on top of the compacted sample.

Step3: Place the perforated aluminum plate with adjustable stem attached on the filter paper on

top of the soil.

Step4: Apply a surcharge weight should not be less than 4.5Kg.

Step5: Place the mold in a water bath so that the water covers the top of the sample.

Step6: Place the expansion apparatus on the mold and take the initial dial gage readings for the

swelling measurements.

Step7: Allow the specimen to soak for 4 days and maintain the constant water level inside and

outside the mold.

Step8: At the end of the soaking period take a final dial gauge reading and calculate the swelling

percentage.

Step9: Repeat steps 8+9 from dry sample.


30

Results and Calculations

- Plot the readings of load against the readings of penetration and draw a smooth curve through the

points.

- The curve is mainly concave downwards, if not we have to correct it.

(Correction of Load-Penetration Curves)


31

- From curve obtained make a computation of the load at penetration of 2.5mm and 5mm. The

obtained values in pounds are expressed as percentages of the standard loads of 3000lb and 4500lb,

respectively.

- Calculate CBR as follows:

I2.5 =

* 100%

I5 =

* 100%

The CBR number is usually based on the load ratio for a penetration of 2.5mm (0.1 in), if the CBR

value at a penetration of 5mm is larger, the test should be redone. If the second test yields also a

larger CBR number at 5mm penetration, the CBR for 5mm should be used.

So,

- IfI2.5> I5take I2.5as CBR.

- If I2.5< I5 repeat the test on another soil sample

In the case that the second test gives I2.5< I5 take I5as CBR.

% swelling =

*100%

CBR No. General rating Uses

0-3 Very poor Sub grade

7-3 Poor Sub grade

20-7 Fair Sub base

20-50 Good Base or Sub base

>50 Excellent Base


32

إختبارات الخلطة الإسفلتية

(1تجربة رقم)

الخلطات الإسفلتية بطريقة مارشال تصميم


33

(Marshall Mix Design)

#8

Objectives

1) Determine the optimum binder content in a mix.

2) Determine the stability and resistance to plastic flow of bituminous mixtures using the Marshall

apparatus.

Theory

The Marshall method of mix design has been widely used with satisfactory results. Developed by

the corps of engineers. The test is relatively a simple one and uses simple apparatus. In the test a

sample specimen 4in in diameter and 2½in high is prepared by compacting in a mold on both faces

with a compacting hammer that weighs 10lb and has a free fall of 18in depending upon the design

traffic, either 75blows for heavy traffic, 50blows for medium traffic, or 35blows for light traffic.

the density and voids are determined and the specimen is heated to 140ºF (60ºC) for the Marshall

stability and flow tests. Our test will be made on medium loading criteria.

Final Mix should have:

1) Sufficient asphalt to ensure a durable pavement.

2) Sufficient mix stability to satisfy the demands of traffic without distortion or displacement.

3) Sufficient voids in the total compacted mix to allow for a slight amount of additional

compaction under traffic loading without flushing, bleeding and loss of stability, yet low enough

to keep out harmful air and moisture.

4) Sufficient workability to permit efficient placement of the mix without segregation.

Mix Components:

Aggregate:

1- Shape:

Tough, bulky, high density, low porosity, angular, Los Angeles Abrasion Value <25%.


34

2- Grading:

Coarse: retained on sieve No.4

Fine: Passing sieve No.4 and retained on sieve No.200

Filler: Passing No.200

Asphalt Cement:

AC 60-70: for hot weather

AC 80-100: for middle weather

AC 120-150: for cold weather

Voids Terminology:

VIM : Voids In Mix, should be between (3-5)% of the mix

1- For good workability

2- To allow the expansion of the mix

If VIM < 3% that lead to bleeding, means no enough space for bitumen to fill the sample and

therefor carry the traffic load

If VIM >5% means a very high porous specimen. Thus, ease for water and air to flow inside the

sample and therefore segregation.

VMA: Voids in mineral aggregate after rolling and it must be greater than 14%.

VFA :Voids filled with asphalt, should be between (68-76)%.

Flow:

The amount of movement, or strain occurring between no load and the maximum load, is the flow

value of the specimen. The specimen is needed to be flexible, not too hard so it will disintegrate

nor too liquid. The limits of flow are(2-4) mm.


35

Stability:

The max load that cause failure of the specimen at 60 c, the value of stability depends on traffic

conditions:

1- Heavy traffic 750 Kg, compact 75 blows at both sides of sample

2- Medium traffic 550 Kg, compact 50 blows at both sides of sample

3- Light traffic 350 Kg, compact 35 blows at both sides of sample

The specimen is placed in a cylindrically shaped split breaking head and is loaded at a rate of

50.8mm/min. The maximum load registered during the test in Kg is designated as the Marshall

stability of the specimen. The stability we want to get is 550Kg. This value should be

evaluated in Kg for the standard height of a specimen which equals 63.5mm (2.5”). The height

of the specimen may not be standard, so a correction factor must be multiplied by the stability

value we gained. We use the following eqs:

Stability corrected = Stability (Kg) * correction factor

Volume of specimen

cm3

Height of specimen

mm

Correction

Factor

457 – 470 57.1 1.19

471 – 482 68.7 1.14

483 – 495 60.3 1.09

496 – 508 61.9 1.04

509 – 522 63.5 1

523 – 535 65.1 0.96

536 – 546 66.7 0.93

547 – 559 68.3 0.89

560 – 573 69.9 0.86


36

Apparatus:

1) Specimen mold assembly. The cylindrical molds are 101.6mm in dia. and 76.2mm in height.

2) Specimen extractor.

3) Compaction hammers weighing 4.54Kg and having a free fall of 457mm.

4) Compaction pedestal.

5) Specimen mold holder.

6) Breaking head.

7) Loading jack.

10) Oven and/or hot plates.

11) Mixing apparatus.

12) Water bath.

13) Containers, thermometers, balance, mixing tools, spoons, heat proof gloves etc.

Procedure:

1) Prepare aggregates to a particular grading specification.

2) Bring three pans. Weigh into each pan an amount of the prepared aggregate that will produce a specimen

having a height of about 63.5mm each pan has 1200gm aggregates

3) Heat the aggregates to the specific mixing temperature (170ºC).

4) Place the heated aggregates into the mixing bowl and put them on the balance.

5) Determine the weight of the bitumen, which has been heated to the same temperature, depending on the

%AC used and pour the bitumen on the aggregates.

6) Place the bowl on the heater and start mixing the ingredients thoroughly and quickly so that all aggregate

particles are coated.

7) Bring the pre-heated to the same temperature mold and place a filter paper in the bottom of it.

8) Place the mixture in the mold and compact it with a rod 25 strikes

9) Remove the collar, smooth the surface of the specimen and place it on the pedestal. Apply 50blows.

10) Remove the base plate and collar and reverse and re-assemble the mold, and then apply the same

number of blows to the other face.

11) Allow the sample to cool then extrude it from the mold and allow it to cool at room temperature

overnight.

12) Measure the height of the sample and weigh it in the air, in the water and at SSD condition for the

measurements of bulk density.

13) Place the sample in a hot path (60 c) for 30min and then apply the stability and flow tests on it (Place it

in the Marshall apparatus). Take readings for stability and flow at the failure of each sample.

14) Repeat the above procedure with different AC% and record your calculations in the table at Data Sheet.


37

Marshall Calculations:

1) Unit weight [g/cm3]:

Unit weight = Gmb * w

Where :

Gmb: Bulk specific gravity of mixture

w = Density of water

Gmb=

w= 1g/cm3

2) Voids in Mineral Aggregate VMA [ %]

VMA =100 -

Where:

Pagg = Percent of agg by wt of total mix

Gmb: Bulk specific gravity of mixture

Gsb: Bulk specific gravity of aggregate

Gsb =

Where:

Pcoarse = Percent of coarse agg by wt of total mix

Pfine = Percent of coarse agg by wt of total mix

Pfiller = Percent of coarseagg by wt of total mix

Gsb of coarse : Bulk specific gravity of coarse

Gsb of fine : Bulk specific gravity of fine

Gsb of filler : Bulk specific gravity of filler


38

3) Voids in Total Mix VIM [%]:

VIM = 100

Where:

Gmb: Bulk specific gravity of mixture.

Gmm: Max specific gravity of mixture (no air voids).

Gmm =

Where:

A: mass of sample in air.

D: mass of flask filled with water.

E: mass of flask and sample filled with water.

4)Voids Filled with Asphalt VFA [%]:

VFA =

*100%

Where:

VMA: voids in mineral aggregate.

VIM: voids in total mix.

Optimum


39

Asphalt Content:

O.A.C =

NOW...

The paving mixtures containing the optimum asphalt content can be determined and compared

with specifications.

Stability - Medium Traffic

Flow (2-4) mm

VIM (3-5) %

VMA > 14%

VFA (68-76)%

Summary of Marshall Mix Design Method:

1) Preparation of Marshall specimens.

2) Conduct the Marshall Stability and Flow Test on each specimen.

3) Compute the average unit weight and voids for each percent of asphalt used in the testing

procedure.

4) Tabulate and plot the test results.

5) Determine the Optimum binder content of the mix design.

6) Check the result obtained with Marshall Design Specifications.


40


مقاومة الإنزلاق للطبقة السطحية


41

Skid Resistance Test and Surface Texture Depth Measurement Test

#9+10

MEASURING SURFACE FRICTIONAL PROPERTIES USING BRITISH PENDULUM SKID RESISTANCE TESTER.

The British Pendulum Skid Resistance Tester is an impact type pendulum used to measure the energy loss when a rubber slider edge is propelled over a test surface. The values measured represent the frictional properties and are expressed as BPN (British Pendulum Number).

Skidding In skidding phenomenon, the distance travelled by wheel on the road is more than the circumferential movement. When brakes are applied, wheels get locked and still if the vehicle moves ahead, longitudinal skidding is said to occur. Skid Resistance Slipping In slipping, the distance traveled by wheel on the road is less than the circumferential movement. If the wheels of the vehicle are rotating but the vehicle is not moving forward, then slipping is said to occur.

MEASUREMENT OF TEXTURE DEPTH It is also necessary to record the surface texture of the road surface tested. This is measured by Sand Patch Method. A known volume of fine sand of uniform particle size is poured on the road and spread to form a patch of a regular shape so that its area couldn‟t be measured. Sand should be spread in such a manner that all “valleys” are filled to level of “peaks”. Then the texture depth can be computed by using the formula;

TEXTURE DEPTH = VOLUME OF SAND / AREA OF PATCH


42

More the texture depth, better is the road surface but a high value of texture depth also increases

the chances of severe injuries.

SCOPE & SIGNIFICANCE Friction between vehicle and road surface plays a vital role in determining the

maximum operating speed and the distance required in safely stopping the vehicles.

Road pavements are designed to provide reasonably high coefficient of friction but with the movement of traffic, the aggregates in the wearing coarse of the road get polished resulting in reduction of the frictional or skid resistance of the road. Skid Resistance

British Pendulum Tester is used to measure the frictional resistance of road at sections which appear to be potentially slippery and unsafe against skidding.

British Pendulum Tester is used for field and laboratory tests.

ROAD SURFACE TEXTURE TEXTURE DEPTH

Coarse/Open Texture ≥ 0.02”

Medium Texture 0.02” – 0.01”

Fine Texture ≤ 0.01”


43

FACTORS AFFECTING SKIDDING RESISTANCE

Condition of Tires – Vehicles having smooth tires would have slightly lower skidding resistance.

Effect of Road Temperature – Skidding resistance of wet roads is higher in winter than in summer. Skidding resistance of roads is at its lowest between April and September. So roads with satisfactory values in winter may prove slippery during summer. Resistance

Effect of Water – Skidding resistance is lower on wet than on dry pavements.

Ø Type of aggregate – sand stones and granites are more resistant to polishing action than limestone.


44

Higher the skid-resistance results, better is the road surface but a high value of skid-resistance also increases the chances of severe injuries. APPARATUS

(a) Parts

Slider – Slider assembly consists of an aluminum backing plate to which a rubber strip 3‟‟ x 1‟‟ x ¼‟‟ is bonded.

Leveling screws Scale Drag pointer Locking and control knobs Frictional rings (b) Accessories

Contact path gauge – shall consist of a thin ruler suitably marked for measuring contact path length between (4 7/8‟‟ and 5‟‟).

Water container Surface thermometer and Brush


45

REPARATION OF APPARATUS

Leveling – apparatus is levelled using 3 levelling screws until the bubble is centered in the spirit level. Zero adjustment – raise the pendulum mechanism by loosening locking knob, till it swings free of test surface. Tighten the knob. Place pendulum in release position and drag pointer in horizontal position and drag pointer in horizontal position. Execute a free swing and note the pointer reading. If reading is not zero; make adjustment by friction ring until pendulum swing carries the pointer to zero. Skid Resistance Slide length adjustment – with pendulum hanging free, place spacer under adjusting screw of lifting handle and allow pendulum to move slowly to the left until the edge of the slider touches the surface. Place gauge beside slider and parallel to the direction of swing to verify the length of contact path which should be between (4 7/8‟‟ and 5‟‟) on flat surfaces as measured from trailing edge to trailing edge of the rubber slider. Sk id Resistance Place pendulum in release position and rotate drag pointer counter clockwise until it comes to original position. Inspect the road and choose the section to be tested. Set the apparatus so that the slider swings in the direction of traffic.

TEST PROCEDURE

Ø Apply sufficient water to cover the test area thoroughly. Execute one swing but don‟t record reading.

Ø Make four more swings, rewetting the test area each time and record the results. The readings should not differ by more than 3 units. Skid Resistance

Report the individual values as B.P.N. also note down the age, condition, texture and location of test area.


46

CATEGORY TYPE OF SITE „SKID RESISTANCE‟ ON WET SURFACE

STANDARD OF SKIDDING RESISTANCE REPRESENTED

A

Most difficult sites such as;

Above 65

„Good‟: fulfilling the requirements even of fast traffic, and making it most unlikely that the road will be the scene of repeated accidents.

i)- Roundabouts

ii)- Bends with radius less than 500 ft on derestricted roads.

iii)- Gradients, 1 in 20 or steeper, of length greater than 100 yd.

iv)- Approach to traffic lights on derestricted roads.

B*

General requirements, i.e. roads and conditions not covered by categories A & C.

Above 55

„Generally Satisfactory‟: meeting all but the most difficult conditions encountered on the roads.

C*

Easy sites, e.g. straight roads, with easy gradients and curves, without junctions, and free from any features, such as mixed traffic, especially liable to create conditions of emergency.

Above 45 „Satisfactory only in favorable circumstances.‟

D All sites Below 45 „Potentially Slippery‟

* On smooth-looking or fine-textured roads in these categories, vehicles having smooth tires may not find skid-resistance adequate. For such road accident studies should also be made to ensure that there are no indications of difficulties due to skidding under wet conditions.

civil engineering department - philadelphia university

Documents