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

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15design system implemented at three levels. The level one methods relied totally on volumetricanalysis to determine mix proportions. The other levels of Superpave analysis require complexequipment and have not been implemented. There is ongoing research to refine Superpavewith respect to quantifying the effects of aggregate size, type and gradation on the mixture andcorrelating these data with pavement performance. In addition, research is being conducted todevelop tests for quantifying the asphalt concrete mechanical properties.The Superpave mix design process starts with aggregate evaluation. Aggregate characteristicsare identified as either source properties or consensus properties. Source properties aredefined by the purchasing agency. The WVDOH Marshall requirements in Table 2.1 are used asthe Superpave source property specifications, with the exception that the flat and elongatedproperty is treated as a consensus property. Consensus aggregate properties were defined bythe Superpave researchers to ensure mixes made with the aggregates have good performancecharacteristics. The researcher envisioned that all agencies using Superpave would adopt thesespecifications without modification for local conditions. The consensus aggregate properties aregiven in Table 2.3. WVDOH has implemented these specifications, but has augmented themwith requirements for skid-resistant aggregates. The consensus aggregate properties are:- coarse aggregate angularity,Table 2.3 Superpave Consensus Aggregate Properties.Design LevelCourseAggregateAngularity (%min)FineAggregateAngularity(% min)Sand Equivalency(% min)Flat andElongated(% min)Light Traffic 55/- - 40 -Medium Traffic 75/- 40 40 10Heavy Traffic 85/80 45 45 10*85/80 denotes min percentages of one fractured face % / two fracturedface- coarse aggregate flat and elongated,- fine aggregate angularity and,- sand equivalency.Coarse aggregate angularity is evaluated by the percent weight of aggregates with one andmore than one fractured face. The test is performed on materials retained on the 4.75mm
16sieve. This is somewhat different than the WVDOH Marshall requirement that specifies theminimum percent of material with two fractured faces.Coarse aggregate flat and elongated is evaluated by the percent mass of aggregates whose ratioof longest dimension to smallest dimension is greater than 5. This test is performed on materialretained on the 9.5mm sieve. Superpave limits the amount of flat and elongated particles toless than 10 percent. The WVDOH Marshall specification limits flat and elongated particles to 5percent based on a 4:1 ratio.Fine aggregate angularity, FAA, is evaluated using the Uncompacted Void Content procedure,AASHTO T304 - 96. The test is performed on material passing the 2.36mm sieve. This testmethod was available prior to the development of Superpave, but was not a requirement forasphalt concrete mix design. The purpose of the test is to ensure the fine aggregates havesufficient angularity and texture to produce a rut resistant mix. Inclusion of the FAArequirement is controversial, so further attention is focused on this test and specification laterin the chapter.The sand equivalency test is used to evaluate the clay content of materials passing the 4.75mmsieve. This test was implemented by some states prior to Superpave, but is a new requirementfor the WVDOH.Superpave requires that the blended aggregates also meet this specification. The tests can beperformed on materials from the individual stockpile then mathematically combined as:Xx1P1p1P p11x2P2pP p222xnPnpP pnnn[2.11]Where,X = the consensus test value for the aggregate blendx i = the consensus test result for stockpile iPi = the percent of stockpile i in the blendp i = the percent of stockpile i that either passes or is retained on the dividing sieve.The dividing sieves for the tests are:
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: 14The WVDOH procedure for determini
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 and 38: 28Table 2.6 WVDOH Marshall and Supe
Page 39 and 40: 30Table 2.9 Habib Marshall Analysis
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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