Asphalt Concrete Properties - Memphis

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A compacted asphalt concrete specimen has a mass in air of 1200 g and an apparent mass in water of 650 g. If the maximum specific gravity of the mix is 2.35 , ...
Asphalt Concrete Properties

Mix Volumetrics Aggregate Particle (MG ,VG)

Effective Asphalt (MBE ,VBE) CIVL 3137

Absorbed Asphalt (MBA ,VBA)

Water Permeable Pores 2

Mix Volumetrics Air Voids (VA)

CIVL 3137

3

Mix Volumetrics

CIVL 3137

4

Bulk Volume Aggregate Particle

Water Permeable Pores CIVL 3137

5

Net Volume Aggregate Particle

Water Permeable Pores CIVL 3137

6

Effective Volume Aggregate Particle

Absorbed Asphalt

Water Permeable Pores CIVL 3137

7

Mix Volumetrics   MB MM

M  bulk density of compacted mix  V M  maximum density of mix  VMM

MB  100% M VA AV  VTM  voids in total mix   100% V V  VA VMA  voids in mineral aggregate  BE  100% V VBE  100% VFA  voids filled with asphalt  VBE  VA PB  binder (asphalt) content 

CIVL 3137

9

Voids in Total Mix (Air Voids)  mb AV  VTM  1   mm

   100% 

mb = bulk density of compacted mixture D 2726 - Bulk Specific Gravity and Density of Compacted Bituminous Mixtures

mm = maximum density of the mixture D 2041 - Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures CIVL 3137

10

Voids in Total Mix (Air Voids)  G mb AV  VTM  1   G mm

   100% 

Gmb = bulk specific gravity of compacted mixture D 2726 - Bulk Specific Gravity and Density of Compacted Bituminous Mixtures

Gmm = maximum specific gravity of the mixture D 2041 - Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures CIVL 3137

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Example A compacted asphalt concrete specimen has a mass in air of 1200 g and an apparent mass in water of 650 g. If the maximum specific gravity of the mix is 2.35, what is the VTM (air void content) of the specimen?

CIVL 3137

12

Voids in Mineral Aggregate 5

CIVL 3137

VTM

VMA

(Voids in Total Mix)

(Voids in Mineral Aggregate)

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Voids in Mineral Aggregate  mb 1  Pb   VMA  1    100% sb  

mb = bulk density of compacted mixture sb = bulk density of the aggregate blend Pb = asphalt binder content of mixture CIVL 3137

14

Voids in Mineral Aggregate  G mb 1  Pb   VMA  1    100% G sb  

Gmb = bulk relative density of compacted mixture Gsb = bulk relative density of the aggregate blend Pb = asphalt binder content (to the nearest 0.1%) CIVL 3137

15

Bulk Density of Aggregate Blend sb  G sb   w f1 f2 fn 1     G sb G1 G 2 Gn

Gi = bulk relative density of aggregate i fi = fraction of blend from aggregate i CIVL 3137

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Example The compacted asphalt specimen from the previous example has a 6% asphalt content. If the aggregate blend contains 40% screenings (Gs = 2.65), 40% sand (Gs = 2.69) and 20% gravel (Gs = 2.61), what is the VMA of the specimen?

CIVL 3137

17

Voids Filled with Asphalt  VTM  VFA  1    100%  VMA  VFA is the percentage of the available space between the aggregate particles (the VMA) that is occupied by effective asphalt binder rather than by air voids. CIVL 3137

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Example What is the VFA of the compacted specimen from the previous examples?

CIVL 3137

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