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BITUMINOUS MIX DESIGNBITUMINOUS MIX DESIGN

PRESENTATION BYPRESENTATION BYVISHWAS KELKARVISHWAS KELKAR

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OBJECTIVE OF MIX DESIGNOBJECTIVE OF MIX DESIGN

The overall objective for the design of asphalt paving mix The overall objective for the design of asphalt paving mix is to determine and economical blend and gradation of is to determine and economical blend and gradation of aggregates (within the limit of project specification) and aggregates (within the limit of project specification) and asphalt that yield a mix havingasphalt that yield a mix having

1) Sufficient asphalt to insure a durable pavement.1) Sufficient asphalt to insure a durable pavement.2) Sufficient mix stability to satisfy the demand of traffic 2) Sufficient mix stability to satisfy the demand of traffic

without distortion or displacement.without distortion or displacement.3) Sufficient voids in the total compacted mix to allow for a 3) Sufficient voids in the total compacted mix to allow for a

slight amount of addition compaction under traffic load slight amount of addition compaction under traffic load without flushing and loss of stability.without flushing and loss of stability.

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

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METHODS OF BITUINOUS MIX METHODS OF BITUINOUS MIX DESIGNDESIGN

i.i. Marshall MethodMarshall Methodii.ii. Hveem MethodHveem Methodiii.iii. Hubbard MethodHubbard Methodiv.iv. Smith Triaxial MethodSmith Triaxial Methodv.v. Void Content MethodVoid Content Method

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MARSHALL MIX DESIGN MARSHALL MIX DESIGN METHODMETHOD

INTRODUCTION: INTRODUCTION: • • BRUCE MARSHALL formulated the concept of the BRUCE MARSHALL formulated the concept of the

Marshall method of designing paving mixers.Marshall method of designing paving mixers.• • Marshall test procedures have been standardized by the Marshall test procedures have been standardized by the

American Society for testing and material (ASTM) American Society for testing and material (ASTM) Destination D-1559.Destination D-1559.

GENERAL:GENERAL:Two principal features of the Marshall Method Mix Design Two principal features of the Marshall Method Mix Design

are:are:1) Density void analysis and1) Density void analysis and2) Stability flow test of compacted test specimen.2) Stability flow test of compacted test specimen. The Stability of the test specimen is the maximum load The Stability of the test specimen is the maximum load

resistance in Kg that the standard test specimen will resistance in Kg that the standard test specimen will develop at 60°C, when tested develop at 60°C, when tested

The Flow Value is the total movement or strain in unit of The Flow Value is the total movement or strain in unit of 0.25 mm occurring in the specimen between no load and 0.25 mm occurring in the specimen between no load and maximum load during the stability test.maximum load during the stability test.

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EQUIPMENTSEQUIPMENTS

1) Pans (Flat bottom or Rounded bottom)1) Pans (Flat bottom or Rounded bottom)2) Oven2) Oven3) Thermometer3) Thermometer4) Balance4) Balance5) Mixing spoon: - Spatula (large) or Trowel (small)5) Mixing spoon: - Spatula (large) or Trowel (small)6) Compaction pedestal6) Compaction pedestal7) Compaction mould7) Compaction mould8) Compaction Hammer8) Compaction Hammer9) Mould Holder9) Mould Holder10) Extrusion Jack10) Extrusion Jack11) Marshall Testing Machine11) Marshall Testing Machine12) Water bath: 12) Water bath:

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PREPARATION OF TEST PREPARATION OF TEST SPECIMENSPECIMEN

1) 1) No. of specimenNo. of specimen; - ; - Prepare at least 3 and preferably 5 specimens for each Prepare at least 3 and preferably 5 specimens for each combination of aggregates and asphalt content. Marshall method uses combination of aggregates and asphalt content. Marshall method uses standard test specimen of 2½-inch (64 mm) height and 4-inch (102 mm) standard test specimen of 2½-inch (64 mm) height and 4-inch (102 mm) diameter.Each test specimen will usually require an approximately 1.2 Kg of diameter.Each test specimen will usually require an approximately 1.2 Kg of aggregates.aggregates.

2)2) Preparation of Mould and HammerPreparation of Mould and Hammer:: - -Thoroughly clean a specimen mould Thoroughly clean a specimen mould assembly and the face of the compaction hammer and heat them in a assembly and the face of the compaction hammer and heat them in a boiling water bath to a temperature between 93°C to 149°C. boiling water bath to a temperature between 93°C to 149°C.

3)3) Preparation of mixersPreparation of mixers:: - - Weight into separate pan for each test specimen, Weight into separate pan for each test specimen, the amount of each size fraction required to produce a batch that will result the amount of each size fraction required to produce a batch that will result in a compacted specimen 63.5 mm ± 1.3 mm in height. This will be normally in a compacted specimen 63.5 mm ± 1.3 mm in height. This will be normally about 1.2 Kg. It is generally desirable to prepare a trail specimen prior to about 1.2 Kg. It is generally desirable to prepare a trail specimen prior to preparing the aggregates batching. preparing the aggregates batching.

4)4) The aggregates are heated upto 120°C and bituminous a 150°C to 160°C. The aggregates are heated upto 120°C and bituminous a 150°C to 160°C. Avoid overheating and reheating of material. Form a crater in dry blended Avoid overheating and reheating of material. Form a crater in dry blended aggregates and weight the required amount of asphalt into the mixer in aggregates and weight the required amount of asphalt into the mixer in accordance with accurate weight batch. At this point the temperature of the accordance with accurate weight batch. At this point the temperature of the aggregates and asphalt must be within the limit of mixing temperature that is aggregates and asphalt must be within the limit of mixing temperature that is 150°C to 160°C. Mix the aggregates and asphalt preferably with a 150°C to 160°C. Mix the aggregates and asphalt preferably with a mechanical mixer or by manually with trowel to yield a mixer having uniform mechanical mixer or by manually with trowel to yield a mixer having uniform distribution of asphalt.distribution of asphalt.

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PREPARATION OF TEST PREPARATION OF TEST SPECIMENSPECIMEN

COMPACTION OF SPECIMEN:COMPACTION OF SPECIMEN: Place the entire batch in the mould; spade the mixer vigoursly with a Place the entire batch in the mould; spade the mixer vigoursly with a

heated spatula or trowel,The temperature of the mixer immediately heated spatula or trowel,The temperature of the mixer immediately prior to compaction shall be within the limit of compaction prior to compaction shall be within the limit of compaction temperature otherwise it shall be discarded.temperature otherwise it shall be discarded.

Replace the collar, place the mould assembly on the compaction Replace the collar, place the mould assembly on the compaction pedestal in the mould holder apply 75 blows with the compaction pedestal in the mould holder apply 75 blows with the compaction hammer using a freefall of 457 mm on one side of the mould. Hold hammer using a freefall of 457 mm on one side of the mould. Hold the axis of the compaction hammer as nearly perpendicular to the the axis of the compaction hammer as nearly perpendicular to the base of the mould assembly as possible during compaction. base of the mould assembly as possible during compaction. Remove the base plate and collar and reverse and reassemble the Remove the base plate and collar and reverse and reassemble the mould. Apply same no. of compaction blows to the face of reverse mould. Apply same no. of compaction blows to the face of reverse specimen. After compaction remove the base plate and allow the specimen. After compaction remove the base plate and allow the specimen to cool in at untill no deformation will result when specimen to cool in at untill no deformation will result when removing it from the mould. Remove the specimen from the mould removing it from the mould. Remove the specimen from the mould by means of and extrusion jacks or by other compression device by means of and extrusion jacks or by other compression device and then place on a smooth and level surface untill ready for testing. and then place on a smooth and level surface untill ready for testing. Normally specimens are allowed to cooled overnight.Normally specimens are allowed to cooled overnight.

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TEST PROCEDURETEST PROCEDUREIn Marshall Method each compacted test specimen is subjected to the following test:In Marshall Method each compacted test specimen is subjected to the following test: 1) Bulk specific gravity determination1) Bulk specific gravity determination 2) Stability and Flow Test2) Stability and Flow Test 3) Density and Void analysis3) Density and Void analysisSTABILITY AND FLOW TEST:STABILITY AND FLOW TEST: After the bulk specific gravity of the test specimen has been determined, StabilityAfter the bulk specific gravity of the test specimen has been determined, Stability Flow test is performed as follows:Flow test is performed as follows: 1) Immerse specimen in water bath at 60°C±1°C for 30 to 40 minute before test.1) Immerse specimen in water bath at 60°C±1°C for 30 to 40 minute before test. 2) Thoroughly clean inside surface of testing head. Temperature of head shall be 2) Thoroughly clean inside surface of testing head. Temperature of head shall be

maintained between 21°C to 38°C using a water bath. Lubricate guide rod with thin maintained between 21°C to 38°C using a water bath. Lubricate guide rod with thin film of oil so that upper test head will slide freely without binding. If a proving ring is film of oil so that upper test head will slide freely without binding. If a proving ring is used to measured applied load, see that dial indicator is firmly fixed and zeroed at no used to measured applied load, see that dial indicator is firmly fixed and zeroed at no load position.load position.

3) With testing apparatus in readiness, remove the test specimen from water bath and 3) With testing apparatus in readiness, remove the test specimen from water bath and carefully place specimen in testing head and centre it into position.carefully place specimen in testing head and centre it into position.

5) Apply test load to the specimen at constant rate of deformation 2 inches5) Apply test load to the specimen at constant rate of deformation 2 inches (51 mm) per minute until failure occurs. The total no. of Kg required to produce failure (51 mm) per minute until failure occurs. The total no. of Kg required to produce failure

of the specimen at 60°C shall be recorded as its Marshall stability value.of the specimen at 60°C shall be recorded as its Marshall stability value. 6) While stability test is in progress, hold the flow meter firmly in position over a guide 6) While stability test is in progress, hold the flow meter firmly in position over a guide

rod and remove as the load being to decrease by taking reading and recording it. This rod and remove as the load being to decrease by taking reading and recording it. This reading is the flow value for the specimen, expressed in unit of 1/100 inches (0.25 reading is the flow value for the specimen, expressed in unit of 1/100 inches (0.25 mm).mm).

7) The entire procedure, both stability and flow test, starting with removal of specimen 7) The entire procedure, both stability and flow test, starting with removal of specimen from water bath up to testing the specimen and taking the reading shall be completed from water bath up to testing the specimen and taking the reading shall be completed within a period of 30 seconds.within a period of 30 seconds.

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MARSHALL DESIGN MARSHALL DESIGN CRITERIACRITERIA

DETAIL DBM SDBM BC/AC

STABILITY(KG) 900 820 900

FLOW(MM) 2 TO 4 2 TO 4

2 TO 4

VIM (%) 3 TO 6

3 TO 6

3 TO 6

VFB (%) 65 TO 75

65 TO 78 65 TO 75

SEE THE

TABLE

BELOWMAXI MUM

SIZE OF

AGG.(MM)

AIR VOIDS

3% 4%

5%

9.5 14 15 16

12.5 13 14 15

19.0 12 13 14

25.0 11 12 13

37.5 10 11 12

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TRENDS AND RELATION OF TRENDS AND RELATION OF TEST DATATEST DATA

CDM

2.522.542.562.582.602.622.64

1 2 3 4 5

STABILITY

1100

1200

1300

1400

1 2 3 4 5

FLOW

4

4.5

5

1 2 3 4 5

VIM

3.0004.0005.0006.0007.0008.0009.000

1 2 3 4 5

VMA

17.0017.5018.0018.5019.0019.5020.0020.5021.00

1 2 3 4 5

%BITUMEN

VMA

VFB

50.00

60.00

70.00

80.00

1 2 3 4 5

%BITUMEN

VFB

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DETERMINATION OF OPTIMUM DETERMINATION OF OPTIMUM BINDER CONTENTBINDER CONTENT

DETAILS CRITERIA TO FIND OBC

SATISFYING CRITERIA

STABILITY (KG) PEAK OF THE CURVE ABOVE MINI. VALUE

FLOW (MM) AVERAGE VALUE 2T04

CDM (gm/cc) PEAK OF THE CURVE -

VIM(%) AVERAGE VALUE 3TO5OR3TO6

VMA (%) TANGENTIAL POINT REFER ABOVE TABLE

VFB (%) AVERAGE VALUE RANGE WILL BE GIVEN DEPENDING ON TYPE

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ADJUSTMENT AND ADJUSTMENT AND EVALUATION OF MIX EVALUATION OF MIX

DESIGNDESIGN The following is a general guide for adjusting the trial mix The following is a general guide for adjusting the trial mix

but the suggestion outline may not necessarily apply in but the suggestion outline may not necessarily apply in all cases.all cases.

VOIDS LOW STABILITY LOW VOIDS LOW STABILITY LOW VOIDS LOW STABILITY SATISFACTORY VOIDS LOW STABILITY SATISFACTORY VOIDS SATISFACTORY STABILITY LOW VOIDS SATISFACTORY STABILITY LOW VOIDS HIGH STABILITY SATISFACTORY VOIDS HIGH STABILITY SATISFACTORY VOIDS HIGH STABILITY LOWVOIDS HIGH STABILITY LOW

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