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Block 12 HMA Volumetrics 13

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Block 12 HMA Volumetrics 13

  1. 1. Senior/Graduate HMA Course Hot Mix Asphalt (HMA) Volumetric PropertiesHMA Volumetrics 1
  2. 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, VFAHMA Volumetrics 2
  3. 3. Volumetric Relationships Va VMA Vb V ba Vse Vmm Vmb VsbHMA Volumetrics 3
  4. 4. 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 HMAHMA Volumetrics 4
  5. 5. BSG of Compacted HMA • Asphalt binder mixed with aggregate and compacted into a sample Mass agg. and AC Gmb = Vol. agg., AC, air voidsHMA Volumetrics 5
  6. 6. Testing • Mixing of asphalt and aggregate • Compaction of sample • Mass of dry sample • Mass under water • Mass saturated surface dry (SSD)HMA Volumetrics 6
  7. 7. Testing Obtain mass of dry compacted sampleHMA Volumetrics 7
  8. 8. Testing Obtain mass of specimen at SSDHMA Volumetrics 8
  9. 9. Calculations• Gmb = A / ( B - C ) Where: A = mass of dry sample B = mass of SSD sample C = mass of sample under waterHMA Volumetrics 9
  10. 10. 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 HMAHMA Volumetrics 10
  11. 11. Maximum Specific Gravity Loose (uncompacted) mixture Mass agg. and AC Gmm = Vol. agg. and ACHMA Volumetrics 11
  12. 12. Testing • Mixing of asphalt and aggregate • Cool to room temperature • Mass in air • Mass under waterHMA Volumetrics 12
  13. 13. Testing Loose Mix at Room TemperatureHMA Volumetrics 13
  14. 14. Testing Residual Manometer Metal Bowl with Lid Vacuum PumpShaker Table HMA Volumetrics 14
  15. 15. Calculations• Gmm = A / ( A - C ) Where: A = mass of dry sample C = mass of sample under waterHMA Volumetrics 15
  16. 16. 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 HMAHMA Volumetrics 16
  17. 17. Percent Air Voids Calculated using both specific gravities Gmb Air voids = ( 1 - ) 100 Gmm Mass agg + AC Vol. agg, AC, Air Voids Vol. agg, AC Mass agg + AC = Vol. agg, AC, Air Voids Vol. agg, ACHMA Volumetrics 17
  18. 18. Example Calculations • Air voids: • Gmb = 2.222 • Gmm = 2.423 ( 1 - 2.222 / 2.423 ) 100 = 8.3 %HMA Volumetrics 18
  19. 19. Effective Specific GravitySurface Voids Mass, dry Gse = Effective Volume Solid Agg. Vol. of water-perm. voids Particle not filled with asphalt Absorbed asphalt Effective volume = volume of solid aggregate particle + volume of surface voids not filled with asphaltHMA Volumetrics 19
  20. 20. Effective Specific Gravity 100 - Pb Gse = 100 - Pb Gmm Gb Gse is an aggregate propertyHMA Volumetrics 20
  21. 21. 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 HMAHMA Volumetrics 21
  22. 22. Example Calculations • Mixed with 5 % asphalt cement • Gmm = 2.535 • Gb = 1.03 100 - 5 Gse = = 2. 770 100 - 5 2.535 1.03HMA Volumetrics 22
  23. 23. Voids in Mineral Aggregate VMA = 100 - Gmb Ps Gsb VMA is an indication of film thickness on the surface of the aggregateHMA Volumetrics 23
  24. 24. Example Calculations • Given that Gmb = 2.455, Ps = 95%, and Gsb = 2.703 (2.455) (95)VMA = 100 - = 13.7 2.703 HMA Volumetrics 24
  25. 25. Voids Filled with Asphalt VFA = VMA - Va 100 x VMA VFA is the percent of VMA that is filled with asphalt cementHMA Volumetrics 25
  26. 26. Mass Relationships Air Ma = 0 Mb = P b MT Asphalt MT = Mb + Ms Aggregate Ms = Ps MTHMA Volumetrics 26
  27. 27. Percent Binder Absorbed Pba = Gse - Gsb 100 ( ) Gb Gsb Gse Pba is the percent of absorbed asphalt by mass of aggregateHMA Volumetrics 27
  28. 28. 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 HMAHMA Volumetrics 28
  29. 29. Effective Asphalt Content Pba Pbe = Pb - Ps 100 The effective asphalt content is the total asphalt content minus the percent lost to absorption (based on mass of total mix).HMA Volumetrics 29
  30. 30. 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 HMAHMA Volumetrics 30
  31. 31. Hot Mix Asphalt (HMA) Volumetric Properties Using Phase DiagramsHMA Volumetrics 31
  32. 32. VOL (cm3 ) Gmb = 2.329 MASS (g) air effective asphalt Gb = 1.015 Pb = 5% by mix absorbed asphalt1.000 aggregate Gsb = 2.705 Gse = 2.731 HMA Volumetrics 32
  33. 33. VOL (cm3 ) Gmb = 2.329 MASS (g) air Ma = 0 effective asphalt Gb = 1.015 Pb = 5% by mix absorbed asphalt1.000 Mm = 1.0 x 2.329 x 1.0 = 2.329 aggregate Gsb = 2.705 Gse = 2.731 M= V x G x 1.000 HMA Volumetrics 33
  34. 34. VOL (cm3 ) Gmb = 2.329 MASS (g) air 0 effective asphalt Gb = 1.015 Mb = 0.05 x 2.329 =0.116 Pb = 5% by mix absorbed asphalt1.000 2.329 aggregate Gsb = 2.705 Gse = 2.731 Ms = 2.329 - 0.116 = 2.213 HMA Volumetrics 34
  35. 35. VOL (cm3 ) MASS (g) air 0 effective asphalt Gb = 1.015 0.116 absorbed asphalt1.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 Vse = 2.213 = 0.810 M 2.731x 1.0 Vsb = 2.213 = 0.818 V= G x 1.000 2.705x 1.0 HMA Volumetrics 35
  36. 36. VOL (cm3 ) MASS (g) air 0 effective asphalt 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt1.000 2.329 aggregate 0.818 0.810 Gsb = 2.705 2.213 Gse = 2.731 M Vb = 0.116 = 0.114 1.015 x 1.0 V= G x 1.000 Vba = 0.818 - 0.810 = 0.008 HMA Volumetrics 36
  37. 37. VOL (cm3 ) MASS (g) 0.076 air 0 effective asphalt 0.106 Gb = 1.015 0.114 0.116 0.008 absorbed asphalt1.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 Vbe = 0.114 - 0.008 = 0.106 Va = 1.000 - 0.114 - 0.810 = 0.076 HMA Volumetrics 37
  38. 38. VOL (cm3 ) MASS (g) 0.076 air 0 0.106 effective asphalt 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 0.810 Gsb = 2.705 2.213 Gse = 2.731 M= V x G x 1.000 Mbe = 0.106 x 1.015 x 1.000 = 0.108 Mba = 0.116 - 0.108 = 0.008 HMA Volumetrics 38
  39. 39. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 effective asphalt 0.106 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 Air Voids = 0.076 x 100 = 7.6 % VMA = Vbe + Va = ( 0.106 + 0.076 ) x 100 = 18.2 % HMA Volumetrics 39
  40. 40. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 0.106 effective 0.108 0.114 asphalt 0.116 Gb = 1.015 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 0.810 Gsb = 2.705 2.213 Gse = 2.731 Air Voids = 7.6 % VMA = 18.2 % VFA = ( 0.106 / 0.182 ) x 100 = 58.2 % HMA Volumetrics 40
  41. 41. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 effective asphalt 0.106 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 Air Voids = 7.6 % Eff. Asp. Cont. = ( 0.108 / 2.329 ) x 100 = 4.6 % VMA = 18.2 % VFA = 58.2 % HMA Volumetrics 41
  42. 42. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 effective asphalt 0.106 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 0.810 Gsb = 2.705 2.213 Gse = 2.731Air 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 % HMA Volumetrics 42
  43. 43. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 effective asphalt 0.106 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 Air Voids = 7.6% Max Theo Sp Grav = 2.329 = 2.521 VMA = 18.2 % 1.000 - 0.076 VFA = 58.2 % 1.000 HMA Volumetrics 43
  44. 44. VOL (cm3 ) MASS (g) 0.076 air 0 0.182 effective asphalt 0.106 0.108 0.114 Gb = 1.015 0.116 0.008 absorbed asphalt 0.0081.000 2.329 aggregate 0.818 Gsb = 2.705 0.810 2.213 Gse = 2.731 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 HMA Volumetrics 44
  45. 45. QUESTIONS ?HMA Volumetrics 45

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