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Hot Mix Asphalt (HMA) Volumetric Properties

Hot Mix Asphalt (HMA) Volumetric Properties. 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. V a. VMA. V b. V ba. V se. V mm.

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Hot Mix Asphalt (HMA) Volumetric Properties

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  1. Hot Mix Asphalt (HMA) Volumetric Properties

  2. 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

  3. Va VMA Vb Vba Vse Vmm Vmb Vsb Volumetric Relationships

  4. Mass agg. and AC Vol. agg., AC, air voids Gmb = BSG of Compacted HMA • AC mixed with agg. and compacted into sample

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

  6. Testing Obtain mass of dry compacted sample

  7. Testing Obtain mass of specimen at SSD

  8. Calculations • Gmb = A / ( B - C ) Where: A = mass of dry sample B = mass of SSD sample C = mass of sample under water

  9. Mass agg. and AC Vol. agg. and AC Gmm = Maximum Specific Gravity • Loose (uncompacted) mixture

  10. Testing • Mixing of asphalt and aggregate • Mass in air • Mass under water

  11. Testing Loose Mix at Room Temperature

  12. Testing Residual Manometer Metal Bowl with Lid Vacuum Pump Shaker Table

  13. Calculations • Gmm = A / ( A - C ) Where: A = mass of dry sample C = mass of sample under water

  14. Gmb Gmm Air voids = ( 1 - ) 100 Mass agg + AC Vol. agg, AC, Air Voids Vol. agg, AC Vol. agg, AC, Air Voids = Mass agg + AC Vol. agg, AC Percent Air Voids • Calculated using both specific gravities

  15. Example Calculations • Air voids: • Gmb = 2.222 • Gmm = 2.423 ( 1 - 2.222 / 2.423 ) 100 = 8.3 %

  16. Surface Voids Mass, dry Solid Agg. Particle 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

  17. 100 - Pb Gse = 100 - Pb Gmm Gb Effective Specific Gravity Gse is an aggregate property

  18. 100 - 5 100 - 5 2.535 1.03 Gse = Example Calculations • Mixed with 5 % asphalt cement • Gmm = 2.535 • Gb = 1.03 = 2. 770

  19. Gmb Ps Gsb VMA = 100 - Voids in Mineral Aggregate VMA is an indication of film thickness on the surface of the aggregate

  20. (2.455) (95) 2.703 VMA = 100 - Example Calculations • Given that Gmb = 2.455, Ps = 95%, and Gsb = 2.703 = 13.7

  21. VMA - Va VMA VFA = 100 x Voids Filled with Asphalt VFA is the percent of VMA that is filled with asphalt cement

  22. Ma = 0 Mb = Pb MT MT = Mb + Ms Mass Relationships Ms = Ps MT

  23. Gse - Gsb Gsb Gse Pba = 100 ( ) Gb Percent Binder Absorbed Pba is the percent of absorbed asphalt by mass of aggregate

  24. Pba 100 Pbe = Pb - Ps Effective Asphalt Content The effective asphalt content is the total asphalt content minus the percent lost to absorption (based on mass of total mix).

  25. Hot Mix Asphalt (HMA) Volumetric PropertiesUsingPhase Diagrams

  26. 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

  27. M = V x G x 1.000 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

  28. Gmb = 2.329 MASS (g) VOL (cm3 ) 0 air asphalt Gb = 1.015 Pb = 5% by mix Mb = 0.05 x 2.329 = 0.116 absorbed asph 2.329 1.000 aggregate Gsb = 2.705 Gse = 2.731 Ms = 2.329 - 0.116 = 2.213

  29. Vse = 2.213 = 0.810 M 2.731x 1.0 V = Vsb = 2.213 = 0.818 G x 1.000 2.705x 1.0 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

  30. M Vb = 0.116 = 0.114 V = 1.015 x 1.0 G x 1.000 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

  31. 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

  32. M = V x G x 1.000 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

  33. 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 %

  34. 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 %

  35. 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 %

  36. 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 %

  37. 1.000 - 0.076 1.000 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 %

  38. 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

  39. Questions - ?

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