Evaluation of Triaxial Strength as a Simple Test for Asphalt Concrete RutResistance

摘要

The purpose of this study was to evaluate the use of triaxial strength testing asa simple performance test for evaluating the rut resistance of asphalt concrete mixtures. A total of ten dens-graded asphalt concrete mixtures were tested using standard triaxial strength tests, which involved performing unconfined and confined strength tests on specimens cored from gyratory samples. An abbreviated protocol was also used to characterize the mixtures, which involved direct testing of gyratory specimens in compression and indirect tension (IDT). Six of the mixtures were based on Marshall mix designs placed in Pennsylvania, and four were based upon Superpave mix designs placed in New York State. A significant range in binder grades, aggregate types, and aggregate gradations were represented. It was found that the abbreviated protocol provided more precise estimates of the Mohr-Coulomb failure parameters than the standard triaxial procedure, especially for the cohesion parameter, which can be estimated accurately from the IDT strength. The mixture cohesion was found to relate very well to mixture rut resistance. The IDT strength was found to be an excellent predictor of rut resistance, and is very promising as a simple and effective test for quality control, acceptance testing, and mixture design and analysis.