Hot Mix Asphalt (HMA) Volumetric Properties

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Hot Mix Asphalt (HMA) Volumetric Properties
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HMA Volumetric Terms

• Bulk specific gravity (BSG) of compacted HMA
• Maximum specific gravity
• Air voids
• Effective specific gravity of aggregate
• Voids in mineral aggregate, VMA
• Voids filled with asphalt, VFA

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Volumetric Relationships
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BSG of Compacted HMA

• AC mixed with agg. and compacted into sample

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Testing

• Mixing of asphalt and aggregate
• Compaction of sample
• Mass of dry sample
• Mass under water
• Mass saturated surface dry (SSD)

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Testing
Obtain mass of dry compacted sample
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Testing
Obtain mass of specimen at SSD
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Calculations

• Gmb A / ( B - C )

Where A mass of dry sample B mass of SSD
sample C mass of sample under water
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Maximum Specific Gravity

• Loose (uncompacted) mixture

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Testing

• Mixing of asphalt and aggregate
• Mass in air
• Mass under water

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Testing
Loose Mix at Room Temperature
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Testing
Residual Manometer
Metal Bowl with Lid
Vacuum Pump
Shaker Table
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Calculations

• Gmm A / ( A - C )

Where A mass of dry sample C mass of
sample under water
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Percent Air Voids

• Calculated using both specific gravities

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Example Calculations

• Air voids
• Gmb 2.222
• Gmm 2.423

( 1 - 2.222 / 2.423 ) 100 8.3
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Effective Specific Gravity
Gse
Effective Volume
Vol. of water-perm. voids not filled with asphalt
Absorbed asphalt
Effective volume volume of solid aggregate
particle volume of surface voids not filled
with asphalt
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Effective Specific Gravity
Gse is an aggregate property
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Example Calculations

• Mixed with 5 asphalt cement
• Gmm 2.535
• Gb 1.03

2. 770
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Voids in Mineral Aggregate
VMA is an indication of film thickness on the
surface of the aggregate
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Example Calculations

• Given that Gmb 2.455, Ps 95, and Gsb 2.703

13.7
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Voids Filled with Asphalt
VFA is the percent of VMA that is filled with
asphalt cement
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Mass Relationships
Ms Ps MT
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Percent Binder Absorbed
Pba is the percent of absorbed asphalt by mass
of aggregate
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Effective Asphalt Content
The effective asphalt content is the total
asphalt content minus the percent lost to
absorption (based on mass of total mix).
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Hot Mix Asphalt (HMA) Volumetric
PropertiesUsingPhase Diagrams
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Gmb 2.329
MASS (g)
VOL (cm3 )
air
asphalt Gb 1.015 Pb 5 by mix
absorbed asph
1.000
aggregate Gsb 2.705 Gse 2.731
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Gmb 2.329
MASS (g)
VOL (cm3 )
Ma 0
air
asphalt Gb 1.015 Pb 5 by mix
absorbed asph
Mm 1.0 x 2.329 x 1.0 2.329
1.000
aggregate Gsb 2.705 Gse 2.731
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Gmb 2.329
MASS (g)
VOL (cm3 )
0
air
asphalt Gb 1.015 Pb 5 by mix
0.116
Mb 0.05 x 2.329
absorbed asph
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
Ms 2.329 - 0.116 2.213
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VOL (cm3 )
MASS (g)
0
air
asphalt Gb 1.015
0.116
absorbed asph
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
2.213
0.810
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VOL (cm3 )
MASS (g)
0
air
asphalt Gb 1.015
0.114
0.116
absorbed asph
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Vba 0.818 - 0.810 0.008
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VOL (cm3 )
MASS (g)
0
0.076
air
asphalt Gb 1.015
0.106
0.114
0.116
absorbed asph
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Vbe 0.114 - 0.008 0.106
Va 1.000 - 0.114 - 0.810 0.076
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VOL (cm3 )
MASS (g)
0
0.076
air
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Mbe 0.106 x 1.015 x 1.000 0.108
Mba 0.116 - 0.108 0.008
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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 0.076 x 100 7.6
VMA Vbe Va ( 0.106 0.076 ) x 100
18.2
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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 7.6 VMA 18.2 VFA ( 0.106 /
0.182 ) x 100 58.2
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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 7.6 Eff. Asp. Cont. ( 0.108 /
2.329 ) x 100 4.6 VMA 18.2 VFA 58.2

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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 7.6 Effective Asphalt Content
4.6 VMA 18.2 Abs. Asph. Cont. ( 0.008 /
2.213 ) x 100 0.4 VFA 58.2
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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 7.6 Max Theo Sp Grav 2.329
2.521 VMA 18.2 VFA 58.2
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VOL (cm3 )
MASS (g)
0
0.076
air
0.182
asphalt Gb 1.015
0.106
0.108
0.114
0.116
absorbed asph
0.008
0.008
2.329
1.000
aggregate Gsb 2.705 Gse 2.731
0.818
0.810
2.213
Air Voids 7.6 Effective Asphalt Content
4.6 VMA 18.2 Absorbed Asphalt Content
0.4 VFA 58.2 Max Theo Sp Grav 2.521
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