Comparison of 9.5 mm SuperPave and Marshall Wearing I Mixes in ...

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29Table 2.7 Aggregate Blend ProportionsProportions (%)Aggregate type Blend 1 Blend 2 Blend 3 Blend 4 Blend 5Crushedlimestone66 66 66 66 66Coarse river sand 8 5 10 15 20Fine river sand 21 29 24 19 14Manufacturedsand5 0 0 0 0Results from the experiment are shown in Table 2.8 and 2.9. First, only the blend with themaximum amount of coarse river sand, Blend 5, complies with all the mix design criteria. Allother mixes fail the VFA criteria for the Superpave mixes or fail the stability criteria for theMarshall method. All the Superpave mixes required lower asphalt content than the Marshallmixes. However, this comparison was only meaningful for Blend 5.Table 2.8 Habib Superpave Analysis Results and CriteriaSuperpaveParameter Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 CriteriaVMA 15.1 13.2 14.1 15.0 16.6 13 min.VFA 74.0 69.6 71.5 73.4 75.9 75 - 80AC (%) 5.5 5.1 5.7 6.3 7.3 --N ini 86.9 88.3 87.9 88.2 88.1 89 max.N max 97.5 97.1 97.4 97.5 97.5 98 max.Dust/Binder ratio 0.73 0.73 0.64 0.60 0.46 0.6 - 1.2
30Table 2.9 Habib Marshall Analysis Results and CriteriaMarshall Parameter Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 CriteriaVMA 15.4 15 15.9 17 18.3 13 min.VFA 74 72 75 75 76 70 - 80AC (%) 6.3 5.8 6.5 7.1 7.9 --Stability (N) 3560 3200 3130 4180 5340 5340 min.Flow (mm) 3.0 2.8 3.1 3.7 3.8 2 - 4.62.3 FINE AGGREGATE ANGULARITYThe SHRP researchers developing the Superpave method were very concerned with minimizingpotential pavement deformation or rutting failure of mixtures. The relationship between fineaggregate angularity and texture to rutting potential was well understood. Natural sandpossessing a round shape and smooth texture was known to contribute to mixes susceptible torutting. Some states limited the amount of natural sand in a mix to control rut susceptibility.The SHRP researchers sought a test-based method for limiting the use of fine aggregates withundesirable characteristics. Hence, the Uncompacted Void Content of Fine Aggregate, AASHTOT304-96, was developed and consensus specifications were developed.Implementation of Superpave, with the fine aggregate angularity requirement, has createdconcern in the asphalt paving industry. The influence of fine aggregate angularity on mixperformance was evaluated in two research projects (Huber, 1998 and Casanova, 2000). Bothstudies found problems with the fine aggregate angularity specification.Huber used a reference coarse aggregate with four fine aggregates whose FAA ranged from 38to 48 percent air voids. Mix performance was evaluated with the Asphalt Pavement Analyzerusing beam samples loaded for 8000 cycles. The characteristics of this device are presentedlater in the chapter. Huber’s results are summarized in Table 2.10. The natural sand samplewith the lowest FAA had the best performance. Regression analysis demonstrated nocorrelation between rut depth and FAA. Huber
Page 1 and 2: COMPARISON OF 9.5 MM SUPERPAVE ANDM
Page 3 and 4: iNOTICEThe contents of this report
Page 5 and 6: iiiasphalt concrete wearing courses
Page 7 and 8: vMixing Procedure 78Appendix B Fine
Page 9 and 10: viiTable C-7 Marshall Medium 13% NS
Page 13 and 14: 4Table 1.1 Mix Design Types in Expe
Page 15 and 16: 6CHAPTER 2 LITERATURE REVIEW2.1 INT
Page 17 and 18: 82. determine aggregate stockpile b
Page 19 and 20: 10SieveAllowable PercentPassing Sie
Page 21 and 22: 12Stability is recorded as the maxi
Page 23 and 24: 14The WVDOH procedure for determini
Page 25 and 26: 16sieve. This is somewhat different
Page 27 and 28: 18G sb = bulk specific gravity of a
Page 29 and 30: 20theoretical gravity at the initia
Page 31 and 32: 22D/B est = adjusted dust to binder
Page 33 and 34: 24P b,est - 0.5%,P b,est ,P b,est +
Page 35 and 36: Percent Passing261009080Superpave U
Page 37: 28Table 2.6 WVDOH Marshall and Supe
Page 41 and 42: 32theoretically correct in that the
Page 43 and 44: 34the machine. This variability was
Page 45 and 46: 36CHAPTER 3 EQUIPMENT3.1 INTRODUCTI
Page 47 and 48: 38Hose PressureWheel Load100 psi100
Page 49 and 50: 40mouth. This jar rests on a holder
Page 51 and 52: problematic, as the saturated surfa
Page 53 and 54: 44Mechanical Laboratory Sieve. Afte
Page 55 and 56: Percent Passing4610090100% Limeston
Page 57 and 58: 48Maximum specific gravity is a req
Page 59 and 60: 50gradation. This allowed for direc
Page 61 and 62: Percent Passing521009080Light 100%
Page 63 and 64: 54percentage of aggregate from the
Page 65 and 66: 56Table 5.4 Summary of Volumetric a
Page 67 and 68: 58Table 5.5 Calculated and Adjusted
Page 69 and 70: 60Table 5.6 Results of APA TestsAir
Page 71 and 72: 62exhibit lower rut depths than any
Page 73 and 74: design had significantly more rutti
Page 75 and 76: 66SP L 100LS SP L 64NS -10.335 2.77
Page 77 and 78: 68percent air voids and percent lim
Page 79 and 80: Air Voids (%)Uncompacted Voids (%)7
Page 81 and 82: 72than the Marshall mixes. Table 6.
Page 83 and 84: Voids in the Mineral Aggregate. As
Page 85 and 86: 76REFERENCESAmerican Association of
Page 87 and 88: 78APPENDIX A BUCKET MIXER INSTRUCTI
Page 89 and 90:
80APPENDIX B FINE AGGREGATE ANGULAR
Page 91 and 92:
82Table B-3 Uncompacted Void Conten
Page 93 and 94:
84AGGREGATE DESIGN DATATable C-1 St
Page 95 and 96:
86Table C-3 Computed Blend Gradatio
Page 97 and 98:
88Table C-7 Marshall Medium 13% NS
Page 99 and 100:
90%G mm%AC VMA VTM VFA @ N ini @N d
Page 101 and 102:
92Table C-14 Superpave Light 64% NS
Page 103:
946 2979.3 1696.7 2988.1 2.307 7.09
Page 106 and 107:
971 2912.7 1620.8 2917.9 2.246 7.65
Page 108 and 109:
992 8.40 10.80 7.402 7.90 9.90 7.80
Page 110 and 111:
1011 9.50 6.90 11.502 9.79 7.15 10.
Page 112 and 113:
1032 8.55 5.20 5.95L R RDate Tested
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Comparison of 9.5 mm SuperPave and Marshall Wearing I Mixes in ...

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