Durable superpave mixes in Kansas.

PDFTech ReportK-TRAN: KSU-12-4C1918SuperpavePavement performanceKansasKansas. Dept. of Transportation. Bureau of ResearchAhmed, AnannaAziz, Syeda R.Sabahfar, NassimHossain, MustaqueKansas State University. Transportation CenterKansas. Dept. of Transportation. Bureau of ResearchUS Transportation CollectionApproximately 89% of 11,000 miles of Kansas roads are surfaced with asphalt. Hundreds of thousands of tonsof reclaimed asphalt pavement (RAP) are produced annually in the United States, including in Kansas. This bulkvolume of RAP must be economically managed in order to achieve environmental friendliness. Recycling of RAPconserves natural resources and reduces landfill usage. However, many agencies have reported that increased RAPcontent produces drier hot-mix asphalt (HMA) mixtures than virgin mixtures that are susceptible to prematurecracking.In this research, laboratory-produced Superpave HMA mixtures containing increased percentages (20, 30, and40%) of RAP materials from three RAP sources (Shilling Construction Co., Konza Construction Co., and the KansasDepartment of Transportation project, US-73) were studied for cracking performance. Mix designs were producedusing Superpave design criteria for 12.5-mm nominal maximum aggregate size mixture. The static and repetitiveSemicircular Bending (SCB) test, the Texas Overlay Tester test, the dynamic modulus test, and Simplified ViscoelasticContinuum Damage (S-VECD) tests were performed on laboratory-prepared samples. In general, crackingperformance decreased with increased RAP content. The RAP from the US-73 project performed most consistentlycompared to other two sources of RAP. Test results were analyzed using two-way Analysis of Variance (ANOVA),proving that mixtures containing 4.5% to 4.9% binder performed the best against cracking. The RAP source was foundto have more effect on cracking propensity than RAP content. Mixtures with RAP content up to 40% performedsatisfactorily. Tukey\ue2\u20ac\u2122s pairwise comparison method was used to compare results from all tests; S-VECD wasdetermined to be the most appropriate test to evaluate cracking propensity of HMA mixtures