Laboratory Evaluation of Dynamic Characteristics of a New High-Modulus Asphalt Mixture

Abstract

With the rapid increase in traffic volume and heavy-duty vehicles, rutting has become one of the most serious problems threatening the service quality and life of asphalt pavement. High-modulus asphalt concrete is a promising method to overcome this problem, contributing to the sustainable development of asphalt pavement. In this study, a new composite high-modulus agent (CHMA)-modified asphalt binder and mixture were prepared, and their dynamic mechanical characteristics were investigated by the dynamic shear rheometer, dynamic modulus test, wheel tracking test, frequency sweep test at a constant height (FSCH), and repeated shear test at a constant height (RSCH) to comprehensively evaluate its high-temperature stability. Test results showed that the rheological property of the CHMA-modified asphalt binder was similar to that of low-graded asphalt binder, implying that it had a strong potential in resisting deformation. The dynamic modulus of AC-20(CHMA) was 19,568 MPa at 15 °C and 10 Hz condition, meeting the requirement for the high-modulus asphalt mixture (higher than 14,000 MPa). The dynamic stability of AC-20(CHMA) was 8094 times/mm, lower than that of AC-20(20#), but remarkably higher than that of AC-20(SBS). AC-20(20#) and AC-20(CHMA) both showed strong shear resistance according to the FSCH test results. Under the repeated shear loadings, the growth rate of the shear strain increased rapidly in the primary stage, and then slowed down gradually, finally reaching a constant growth rate. The shear slope of AC-20(CHMA) was between that of AC-20(20#) and AC-20(SBS), demonstrating that its resistance to repeated shear loadings was superior to AC-20(SBS), although slightly weaker than AC-20(20#). The findings in this study provide references for alleviating rutting problems and improving the lifespan of asphalt pavement.