comparison of alternative asphalt concrete rut characterization

BERTHELOT, CROCKFORD & LYTTON 6not to provide proper ranking of the Radisson SPS-9A asphalt concrete mixes concomitant to field ruttingperformance after three years of service.Table 4 Hveem Stability Measurements and Duncan's Pairwise Comparison of Radisson SpecificPavement Studies-9A Asphalt Concrete MixesSPS-9A Test Mean Hveem HveemDuncan's Grouping*Section Stability StabilityCoefficient ofVariation(Percent)900901 28.61 1.94 D900902 40.02 1.44 A900903 32.53 3.32 C900959 30.95 7.38 C900960 34.78 3.71 B900961 30.80 2.70 C D900962 35.32 3.68 BMean 33.29 3.45* Asphalt concrete mixes with same letter are not significantly different.4.3 Unconfined Compressive Strength CharacterizationUnconfined compressive strength testing of asphalt concrete is standardized in ASTM D1074 andAASHTO T167. Unconfined compressive strength testing was performed on triplicate gyratorycompacted samples at seven percent air voids from each Radisson SPS-9A asphalt concrete mix at 5°C,20°C, 40°C, 70°C, and 100°C. Tables 5 and 6 summarize the mean unconfined compressive strengthmeasurements across the Radisson SPS-9A asphalt concrete mixes and test temperatures respectively.A statistical analysis was performed at a 95 percent confidence level to evaluate the significance of theunconfined compressive strength measurements across the Radisson SPS-9A asphalt concrete mixes andtest temperatures employed in the analysis. A two-way analysis of variance concluded that RadissonSPS-9A asphalt concrete mix type, test temperature and the interaction effects of mix type and testtemperature had a significant effect on the mean unconfined compressive strength measurements..Duncan's pairwise comparison determined that the mean unconfined compressive strength of mixes900959 and 900962 were significantly different from all other mixes; however, mixes 900901, 900902,900903, and 900960 were not significantly different; and mixes 900901, 900902, 900903 and 900961were not significantly different. Duncan's pairwise comparison across the test temperatures grouped byRadisson SPS-9A asphalt concrete mix determined that the mean unconfined compressive strengths at5°C, 20°C, and 40°C were significantly different from those at all other temperatures; however, there wasno significant difference between 70°C and 100°C.