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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 Volumetrics

  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 Volumetrics

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

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

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

  6. Testing Obtain mass of dry compacted sample Volumetrics

  7. Testing Obtain mass of specimen at SSD (saturated surface dry) Volumetrics

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

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

  10. Testing • Mixing of asphalt and aggregate • Cool to room temperature • Mass in air • Mass under water Volumetrics

  11. Testing Loose Mix at Room Temperature Volumetrics

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

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

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

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

  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 Volumetrics

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

  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 Volumetrics

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

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

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

  22. Air Ma = 0 Mb = Pb MT Asphalt MT = Mb + Ms Mass Relationships Aggregate Ms = Ps MT Volumetrics

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

  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). Volumetrics

  25. Summary of Terms • VMA = Voids in mineral aggregates • Va = Air voids • VFA = Voids filled with asphalt binder • Gb = Specific gravity, asphalt binder • Gse = Effective specific gravity of aggregate • Gsb = Bulk specific gravity of aggregate • Pbe = % by mass of effective asphalt binder • Pb = % by mass of total asphalt binder • Pba = % by mass of absorbed asphalt binder • MT = Total mass • Ms = Mass of solids • Mb = Mass of asphalt binder • Gmb = Specific gravity of compacted HMA • Gmm = Maximum specific gravity of loose HMA Volumetrics

  26. Hot Mix Asphalt (HMA) Volumetric PropertiesUsingPhase Diagrams Volumetrics

  27. Gmb = 2.329 MASS (g) VOL (cm3 ) air effective asphalt Gb = 1.015 Pb = 5% by mix absorbed asphalt 1.000 aggregate Gsb = 2.705 Gse = 2.731 Volumetrics

  28. M = V x G x 1.000 Gmb = 2.329 MASS (g) VOL (cm3 ) Ma = 0 air effective asphalt Gb = 1.015 Pb = 5% by mix absorbed asphalt Mm = 1.0 x 2.329 x 1.0 = 2.329 1.000 aggregate Gsb = 2.705 Gse = 2.731 Volumetrics

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

  30. 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 effective asphalt Gb = 1.015 0.116 absorbed asphalt 2.329 1.000 aggregate Gsb = 2.705 Gse = 2.731 0.818 2.213 0.810 Volumetrics

  31. M Vb = 0.116 = 0.114 V = 1.015 x 1.0 G x 1.000 VOL (cm3 ) MASS (g) 0 air effective asphalt Gb = 1.015 0.114 0.116 0.008 absorbed asphalt 2.329 1.000 aggregate Gsb = 2.705 Gse = 2.731 0.818 0.810 2.213 Vba = 0.818 - 0.810 = 0.008 Volumetrics

  32. VOL (cm3 ) MASS (g) 0 0.076 air effective asphalt Gb = 1.015 0.106 0.116 0.114 absorbed asphalt 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 Volumetrics

  33. M = V x G x 1.000 VOL (cm3 ) MASS (g) 0 0.076 air effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 0.008 0.008 absorbed asphalt 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 Volumetrics

  34. VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.108 0.106 0.116 0.114 absorbed asphalt 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 % Volumetrics

  35. VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 0.008 0.008 absorbed asphalt 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 % Volumetrics

  36. VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 absorbed asphalt 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 % Volumetrics

  37. VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 0.008 0.008 absorbed asphalt 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 % Volumetrics

  38. 1.000 - 0.076 1.000 VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 absorbed asphalt 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 % Volumetrics

  39. VOL (cm3 ) MASS (g) 0 0.076 air 0.182 effective asphalt Gb = 1.015 0.106 0.108 0.114 0.116 absorbed asphalt 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 Volumetrics

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