Review and analysis of Hamburg Wheel Tracking device test data.

PDFTech ReportKS-14-1C1886SuperpaveAsphalt concrete pavementsRuttingMoisture damageWaste productsPavement performanceMix designPavement crackingAir voidsAggregatesBinder contentThermal stressesKansasKansas. Dept. of Transportation. Bureau of Materials & ResearchRahman, FarhanaHossain, MustaqueKansas State University. Transportation CenterUS Transportation CollectionThe Hamburg Wheel Tracking Device (HWTD) test (TEX-242-F) and the Kansas Test Method KT-56 (KT-56), ormodified Lottman test, have been used in Kansas for the last 10 years or so to predict rutting and moisture damage potential ofSuperpave mixes, especially mixes containing Reclaimed Asphalt Pavement (RAP). Thermal Stress Restrained Specimen Test(TSRST) was performed on selected mixes following AASHTO TP 10. All specimens tested were prepared with the Superpavegyratory compacter.Results showed that the number of wheel passes and rut depth from the HWTD test are significantly different forSuperpave mixes with various RAP content. Recycled Superpave mixtures with crushed gravel aggregates and sand significantlyimprove overall rutting performance compared to crushed stone or crushed stone and gravel combinations in the mix. Aggregatetype also influences rutting performance of virgin Superpave mixtures. Rutting performance of Superpave mixes with or withoutRAP is significantly affected by the binder source.Statistical analysis proved that the total number of wheel passes, creep slope, and stripping slope of Superpave mixes withRAP in HWTD tests are significantly affected by RAP content, binder grade, and asphalt sources at 90% confidence interval. RAPpercentage in the mix, aggregate type, and interaction between RAP content and aggregate type also affect the pure strippingfailure phase (stripping slope) and total wheel passes at the stripping inflection point. Analysis of variance (ANOVA) on Superpavemixtures with RAP showed the number of wheel passes at stripping inflection point and stripping slope are significantly affectedby mix type and binder source. Rutting performance is highly influenced by voids in mineral aggregate (VMA) and RAP asphaltcontent. Superpave mixtures with higher RAP content also tend to fracture at higher temperatures in the Thermal Stress RestrainedSpecimen Test, indicating that these mixtures are more vulnerable to low-temperature cracking. Thus, low-temperature crackingpotential of high RAP mixture must be evaluated during the mixture design process