road materials & bituminous materials

8/22/2019 Road Materials & Bituminous Materials

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Rizal Technological University

College of Engineering and Industrial Technology

ROAD MATERIALS

&BITUMINOUS

MATERIALS

Submitted to:

Engr. Noel Binag

Submitted by:

NAME GRADES


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I. INTRODUCTION

Aggregateis a broad category of coarse particulate material used in construction,including sand, gravel, rushed stone, slag, recycled concrete and geosynthetic aggregates.

These are also used as base material under foundations, roads, and railroads. In otherwords, aggregates are used as a stable foundation or road/rail base with predictable,

uniform properties (e.g. to help prevent differential settling under the road or building),or as a low-cost extender that binds with more expensive cement or asphalt to formconcrete. This chapter will determine the sizes of aggregates used in highwayconstruction and classify the aggregates use in asphalt pavement construction.

Bituminous materials or asphalts are extensively used for roadway construction,primarily because of their excellent binding characteristics and water proofing propertiesand relatively low cost. Bituminous materials consists of bitumen which is a black ordark coloured solid or viscous cementitious substances consists chiefly high molecularweight hydrocarbons derived from distillation of petroleum or natural asphalt, hasadhesive properties, and is soluble in carbon disulphide. Under bituminous materials,

the topic will mainly discuss about determining the different bituminous binders used inasphalt pavement. It will also include the procedure in the construction of asphaltpavement and determine the specifications / standards use in asphalt construction.
https://en.wikipedia.org/wiki/Materialhttps://en.wikipedia.org/wiki/Constructionhttps://en.wikipedia.org/wiki/Sandhttps://en.wikipedia.org/wiki/Gravelhttps://en.wikipedia.org/wiki/Crushed_stonehttps://en.wikipedia.org/wiki/Slaghttps://en.wikipedia.org/wiki/Railroadhttps://en.wikipedia.org/wiki/Railroadhttps://en.wikipedia.org/wiki/Slaghttps://en.wikipedia.org/wiki/Crushed_stonehttps://en.wikipedia.org/wiki/Gravelhttps://en.wikipedia.org/wiki/Sandhttps://en.wikipedia.org/wiki/Constructionhttps://en.wikipedia.org/wiki/Material


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II. BODY OF THE REPORT

ROAD MATERIALS

AGGREGATES

A hard inert mineral material, such as gravel, crushed rock, slag, or crushedstone, used in pavement applications either by itself or for mixing with asphalt.

Aggregates which is intended for either bituminous or Portland cement concretepavement should be of good quality and in accordance with the requirements of

AASHTO standard under ITEM 703 of the Department of Public Works andHighways pecifications which generally provides that:

The aggregates shall consist of hard durable particles or fragments ofcrushed stone, crushed or natural gravel.

AGGREGATE FOR BITUMINOUS PAVEMENT

Generally for bituminous or asphalt pavement, the aggregates constitute 88% to96% by weight or more than 75% by volume. The AASHTO standardspecifications provide that:

The aggregate shall consist of hard, durable particles of fragments ofstone or gravel and sand or other fine mineral particles free from vegetablematter and lumps or balls of clay and of such nature it can be compacted readilyto form a firm, stable layers. It shall conform to the grading requirements shownin table 3 when tested by AASHTO T-11 and 27.

GRADING REQUIREMENTS

SIEVE DESIGNATION MASS PERCENT PASSING

Standardmm

AlternateUS Std.

Grading A Grading B Grading C Grading D

25 1" 100 100 100 100

10 3/8 50-85 60-100

5 No. 4 35-65 50-85 55-100 70-100

2 No. 10 25-50 40-70 40-100 55-100

0.5 No. 40 15-30 25-45 20-50 30-70

0.075 No. 200 5-20 5-20 6-20 8-25


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The following materials are classified under Item 300 of the DPWH standardspecifications.

The coarse aggregate material retained on the 2.00 mm (No.10) sieve shall havea mass percent of wear by the Los Angeles Abrasion Test (AASHTO T-96) of notmore than 45.

When crushed aggregate is specified, not less than 50 mass percent of theparticles retained on the 4.75 mm (No. 4) sieve shall not have at least onefractured face.

The fraction passing the 0.75 mm (No. 200) sieve should not be greater than twothirds of the fraction passing the 0.425 mm (No. 40) sieve.

The fraction passing 0.425 mm (No.40) sieve shall have a liquid limit of notgreater than 35 and a plasticity index range of 4 to 9 when tested by AASHTO T-89 and T-90respectively.

The Department of Public Works and Highways standard specifications classifyaggregate under Item 703, and specifically provides that:

Aggregate shall consist of hard, durable particles of fragments of crushed stone,crushed slug or crushed or natural gravel.

Coarse aggregate is the material retained on the 2.00 mm (No. 10) sieve andshall have a percentage of water or more than 50 for sub-base and not morethan 45 for base and surface courses as determined by AASHTO designationtest T-96.

Fine aggregate is the material passing the No. 10 sieve (2.00 mm) consisting of

natural, crushed sand and fine minerals particles. The Fraction Passingthe 0.075mm (No. 200) sieve should not be greater than 0.66 (2/3) of the fraction passingthe 0.425 mm (No. 40) sieve.

MINERAL FILLER

The strength of the road pavement will be increased ifdust additives whichdenses the graded mixture is added. It is called mineral filler which reduces thevoid contents in the mixture. This dust additive is not the ordinary dust that isbeing found in our floor or tables.

Dust additive is classified into:

Finely powderedlimestone

Slag

Hydrated lime

Portland cement

Trap rock dust

Fly ash


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The DPWH standard specifications relative to mineral filler states that:

Mineral filler shall consist of finely divided mineral matter such as rock dust, slagdust, hydrated lime, hydraulic cement, flyash or other suitable mineral matter. It shallbe free from organic impurities and at the time of use shall be sufficiently dry to flowfreely and shall be essentially free from agglomerations.

AASHTO M-17 provides that:

Percentage passing by weight shall be as follows:

No. 30 (0.66 mm) sieve 50

No. 50 (0.30 mm) sieve 95-100

No. 200 (0.75 mm) sieve 70-100

AASHTO further stipulates that for all materials other than hydrated lime or

Portland cement, the Plastic Index (PI) value shall be 4 or less.

BITUMINOUS MATERIALS

BITUMINOUS MATERIAL

Bituminous material or asphalt is a viscous (gelatinous) liquid used as binder foraggregates in road construction. At normal temperature, asphalt is either lightlythicker than water or hard but brittle material that breaks under a hammer blowwhen cold.

Bituminous material is in liquid form when mixed or combined with aggregates.This liquid form maybe produced either by heating the hard asphalt, by dissolvingin solvent or by emulsifying in water. However, there are bituminous liquidmaterials available and ready to use.

The action of the asphalt binder depends on its type and the aggregate it iscombined with. The purpose of the asphalt binder is to resist the abrasive forcebrought about by heavy traffic.

If the pavement is of the open type, consisting entirely of coarse particles andasphalt, heavy binder is needed requiring more asphalt. On the otherhand, if the

aggregates on the pavement contain fine particles, cohesion will be developed bythe surface tension in the thin asphalt film surrounding these sine particleshence, less viscous asphalt is required.


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BITUMINOUS BINDER

Three different forms of asphalt that are used as binders in pavements are:

(1) asphalt cement;

(2) cutback asphalts; and

(3) asphalt emulsions.

Asphalt Cement

In this form, asphalt behaves as a solid at normal atmospheric temperatures. Toproduce a pavement with it, the asphalt is heated to a temperature (275F/135C) atwhich it becomes fluid and can readily be intermixed with aggregate. The product isvariously called: hot mix, hot mix asphalt (HMA), asphalt concrete, and asphaltcement concrete (acc). The hot mix is then spread out on roadways and compacted.HMA is used to create high-quality pavements as opposed to patch-quality repairs of

pot-holes, or treatments for low-volume country roads.

Asphalt cement is used as binder for almost high types of bituminous pavement.Asphalt cement is a semi-solid hydrocarbons retained after fuel and lubricating oilsare removed from petroleum. The softest grade used for pavement is the 200-300penetration and the hardest is the 60-70 penetration.

Cutback or Liquid Asphalt

To be mixed with aggregate, asphalt must be put into liquid form. With asphaltcement, this is done by heating the binder to a sufficiently high temperature so that itbecomes very fluid. One alternative is to dissolve asphalt more volatile phases of

petroleum that have higher fluidity at low temperatures. Mixtures of asphalt dissolvedin petroleum solvents are typically called cutbacks. Such cutback asphalts can beapplied to roadways. After application, the solvent phase gradually evaporatesleaving behind the asphalt binder. The evaporation of the solvent leads to thehardening of the cutback, and this is called curing.


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Cutback or liquid asphalt is classified into: Slow Curing (SC) road soils

o These use the least volatile petroleum solvents such as diesel andgas oils. The uses are similar to those of MC cutbacks: patchingmixes and prime-coats. An additional application of SC cutbacks is

as dust palliatives on low-volume gravel roads Medium Curing (MC) cutback asphalt

o These use petroleum solvents less volatile than gasoline andnaphtha like kerosene. MC cutbacks are typically used stockpiledpatching mixes, or for prime-coats of roadways, or for some ready-mixing operations.

Rapid Curing (RC) cutback asphalto These are achieved by using highly volatile phases of petroleum

like gasoline or naptha as the solvent. Because these phasesevaporate very quickly, they lead to rapid curing of the cutback.

Emulsified Asphalt

It is well known that water and asphalt will not mix, except under carefullycontrolled conditions using highly specialized equipment and chemical additives.The blending of asphalt cement and water is somewhat like trying to washgrease from your hands with only water. It is not until a detergent or soapy agentof some type is used that grease can be successfully removed. The soapparticles surround the globules of grease, break the surface tension that holdsthem, and allow them to be washed away. Some of the same physical andchemical principles apply in the formulation, production, and use of asphalt

emulsion.Emulsified asphalt is a kind of mixture wherein the minute globules ofasphalt disperses in water. Asphalt content ranges from 55% - 70% by weight.Emulsion could be applied or mixed at normal temperature, because when thewater content evaporates the asphalt remains.

Binder Properties

Adhes ion -Bituminous materials adhere to clean dry surfaces.

Viscosi ty -All bituminous materials are viscous, i.e. when subject to a long term

load they deform continuously.

Softening point -This is the temperature at which the binder softens to a pre-determined point.


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PROBLEMS ASSOCIATED WITH BITUMINOUS BINDERS

1. The thickness of asphalt in the pavement ranges from 0.005 to 0.10 mm. Testresults showed that the thicker the asphalt film, the lesser is the process ofaging. Where pavement has lower percentage of voids, aging is alsorelatively low.

2. Mixtures that are too dry, cracks and breaks easily.3. Higher asphalt content and lower percentage of voids may cause instability of

the pavement.4. Improper construction procedures can age asphalt prematurely. One example

is mixing asphalt with an overheated aggregates.5. Storing the mixed materials for an extended period of mixing temperatures

produces a substantial reduction of asphalt penetration.6. Climatic conditions can seriously affect the behaviour of asphalt binders.7. Different brand or source has variability in behaviour. The viscosity of some

asphalts varies with temperature from that of the others.8. An asphalt meeting a specified penetration requirement at 77F but with high

viscosity temperature ratio will become hard and brittle at lower temperature.

BITUMINOUS PAVEMENT

The bituminous pavement is a combination of mineral aggregate and bituminousbinders. The mixture of rock material particles with asphalt has created so many namessuch as:

Plant mix

Asphalt sheet

Road mix

Armor coat

Oil mat, etc.

Asphalt macadam

Asphaltic concrete

Mastic

National paving

Although several names were affixed to the bituminous pavement, yet, there isonly one thing to remember that, all bituminous roadway is nothing more than amixture of mineral aggregates and asphalt. Meaning, asphalt road is virtually abituminous road.


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Qualities of asphalt road

The surface must free from cracks or raveling due to shrinkage and fatiguefailure

It must withstand weather condition, including the effect of surface water, heat,cold and oxidation

It must be resistant to internal moisture such as water vapor

It must posses a tight or porous impermeable surfaces the case may be suitableto underlying base on sub-base

It must be smooth riding and skid free surface

The success of an asphalt pavement lies or depends of the construction quality

of the sub-grade, and the base course. On the contrary, pavement failure wouldbe considered as a forgone conclusion.

A satisfactory asphalt pavement could be attained under the followingconstruction procedures:

Viscous asphalt binder is heated to a fluid condition and mixed with heatedaggregates. The mixture is then laid and compacted while still hot.

Mixing liquid or emulsion asphalt with aggregates at normal temperature is either

by plant or road mixing. The mixture is laid and compacted at the normaltemperature before the solvent evaporates or the emulsion breaks.

Spread and compact the clean crushed stones, sprayed with heated oremulsified asphalt binder over it. Cover the sprayed pavement with fineaggregates. This process is referred to as the penetration method.

BITUMINOUS concrete PAVEMENT failures

Caused by excessive loads. Heavy loads creates deflection on the road surface,

with insufficient underlying strength. Repetitious underlying of the excessive loadwith roughen and crack the road pavement will ultimately result to completefailure of the roadway

Deflection on the road surface may be the effect of the elastic deformation fromthe consolidation of the base or subsoil or from the combination of elastic andplastic deformation. Repeated heavy wheel load on highly resilient soil causesdeflection leading to fatigue failure of the asphalt surface.


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Alligator or the map cracking of the surface will be substantially evident. Elasticdeformation in the sub-grade penetrate to depth of 6meters although mostly to adepth from the surface.


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DPWH STANDARD SPECIFICATIONS ON PRIME COAT, TACK COAT AND SEALCOAT

ITEM 301- BITUMINOUS PRIME COAT

Materials

Bituminous material is either Rapid Curing (RC) or Medium Curing (MC) cut back

asphalt, whichever specified.

Equipment1. The liquid bituminous material is sprayed by means of a pressure distributor

of not less than 1000 liters capacity mounted on a pneumatic tires of suchwidth and number that the load produced on the road surface will not exceed1kN (100 kg.f) per centimeter width of tire

2. The tank has a heating device able to heat a complete charge of bituminousliquid up to 180C. The heating device shall be such that overheating will notoccur.

3. The flame should not touch directly the casing of the tank containing the

bituminous liquid. The liquid should be insulated that when the tank is filledwith bituminous liquid at 180C, the temperature will not drop to less than20C per hour when the tank is not being heated.

4. A thermometer is fixed to the tank in order to measure the liquid temperaturecontinuously. The tank is furnished with a calibrated dip stick to indicate thecontent.

5. The pipe for filling the tank is furnished with an easily changeable filter.


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6. The distributor has the capacity to vary the spray width of the bituminousliquid in maximum steps for 100mm to a total width of 4 meters. The sprayingbar shall have a nozzle from which the liquid is sprayed in fan-shaped overthe road surface equally distributed over the total spraying width.

7. The pump is furnished with an indicator showing the rate of the liquid flow. A

thermometer is fixed to indicate the temperature of the liquid immediatelybefore it leaves the spraying bar.8. The distributor is furnished with a Tachometer, indicating its forward speed,

visible from the drivers seat.9. The distributor shall be designed where the deviation from the prescribed rate

of application does not exceed 10% and is equipped with a device for handspraying of the bituminous liquid.

Application of bituminous Materials

1. The surface to be treated is swept and cleaned with broom including the

removal of all dirt and other objectionable materials before applying the PrimeCoat.2. Prior to the application of the Prime Coat, the surface is slightly sprayed with

water but not saturated.3. The rate of bituminous material application is within the range of 1 to 2 liters

per square meter.4. The prime coat is left undisturbed for a period of 24 hours and closed to traffic

until it has penetrated and cured sufficiently so that it will not be picked up bythe wheels of passing vehicles.

5. The prime coat should not be in excess of the specified amount. Any excessis blotted with sand or removed.

6. Areas which are not accessible by the distributor is sprayed manually usingthe device for hand spraying.

7. The surface of the road and trees adjacent to the areas being treated isprotected to prevent their being spattered or marred by the asphalt.

ITEM 302 BITUMINOUS TACK COAT

The standard specification for tack coat is the same as that of the prime coat.The difference will be enumerated as follows:

1. The rate of application of either the rapid curing cutback or the emulsifiedasphalt within the range of 0.2 to 0.7 liter per square meter.

2. The tack coat is sprayed in advance on the surface course to permit it to dryinto a Tacky condition. The tack coat is maintained until the next course isapplied.

ITEM 303 BITUMINOUS SEAL COAT


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This item consist of an application of bituminous materials with or without theapplication of aggregate to an existing bituminous surface course.

Materials required1. The approximate amount of materials required for seal coat per square meter

is provided on table 5-142. Bituminous material is the asphalt cement penetration grade 120-150 rapidcuring or medium curing cutback asphalt.

3. The cover aggregate for type 2 seal coat consist of sand or fine screeningfree from dirt or other organic matter.

4. The aggregate for type 3 seal coat is crushed stone, crushed slag or crushedgravel. Only one type of aggregate shall be used in a project unless otheralternative type is approved.

TABLE 5-14 QUANTITY OF MATERIALS FOR SEAL COAT

Material Type-1 Type-2 Type-3Bituminous MaterialL/m

0.20-0.50 0.50-1.00 0.85-1.50

Cover Aggregatekg/m

None 5.00-10.00 8.00-14.00

5. The aggregate shall have a mass percent of wear not exceeding 40 whentested by AASHTO T-96

6. When crushed slag is used, it should be uniformed in density of not less than960 kg. per square meter as determined by AASHTO T-19

TABLE 5-15 GRADING REQUIREMENTS

Sievemm

DesignationInch

Mass Percent Passing

Type-2Type-3

Grading A Grading B

12 - - 100

10 3/8 100 100 85-1000

4.75 No.4 85-100 85-100 10-30

2.36 No.8 60-100 10-40 0-10

1.18 No.16 - 0-10 0-5

0.300 No.50 - 0-5 -

0.150 No.100 0-10 - -

Constructions Requirements1. Seal coating should not be undertaken on a foggy or rainy day or when the

surface to be treated is wet.2. Wet cover coat material should not be used on the work and no seal coating

work be continued at night unless provided with sufficient lighting.


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3. Seal coating operation should not be started until the bituminous surface isthoroughly compacted by traffic and rolling.

4. Seal coating should not be placed on newly constructed or reconditioned roadsufaces in less than ten days after such surface is laid and opened to traffic.

5. Road surface to receive bituminous material should be cleaned of dirt, sand,

dust and objectionable materials. The cleaning should be effected by meansof a rotary power broom or power blower.

Application of Bituminous Materials1. Bituminous material should be applied by means of a pressure distributor at

the rate of approximately 0.9 to 1.8 liters for asphalt cement and 1.5 to 3.0liters for cutback asphalt per square meter of surface in a uniform, unbrokenspread over the section to be treated.

2. The pressure distributor specification including its appurtenances are thesame as that enumerated in Item 301 bituminous Prime Coat

3. Application of bituminous material at the junction of spreads should not

exceed the specified quantity. Any excess be removed from the surface bysqueegee.4. If necessary to obtain proper junction of spreads, a strip of Manila paper

approximately one meter wide and at least as long as the spray bar should beused at the beginning and end of each spread. The paper is removedimmediately after use.

5. Any skipped areas or recognized deficiency should be corrected immediatelyby hand application of operated pressure device.

Spreading of Cover Aggregates1. Immediately after the application of asphalt , the cover aggregate should be

spread evenly over the surface at the rate of approximately 0.004 to 0.007cubic meter per square meter.

2. Spreading is accomplished by aggregate spreader to obtain an even andaccurate distribution. The use of spreader boards attached to the tail gate oftruck should not be permitted.

3. The tires of the aggregate truck should not be allowed to come in contact withthe uncovered and newly applied asphalt.

4. After spreading the cover aggregate, the surface is broomed lightly with anapproved push or drag broom to insure an even distribution then rolled withan approved power roller weighing not less than 5 nor more than 6 tons to auniform surface.

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