Preparation and performance of UHMWP modified asphalt and its high modulus mixture

Abstract

High modulus asphalt mixtures are increasingly being applied owing to their excellent high temperature performance and fatigue resistance. Currently, they are mainly prepared with admixtures. Aiming at problems of complex processes and poor performance-cost ratios of admixture, Ultra-high molecular weight polymer (UHMWP) was selected as basic material, and cross-linked UHMWP was prepared by a crosslinking reaction. The performances of the UHMWP modified asphalt and cross-linked UHMWP modified asphalt were then compared. UHMWP was determined as modifiers. Through dynamic shear rheometer (DSR) and bending beam rheometer (BBR), the influences of UHMWP content on the basic performance and rheological performance of asphalt were investigated, and their microscopic modification mechanisms were revealed by Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The change laws of the dynamic modulus of the UHMWP high modulus mixture with temperature and frequency were clarified, and the change characteristics of their dynamic modulus master curves at different temperatures in different frequency ranges were analyzed. Subsequently, the performances of the different mixtures were evaluated. The results indicate that the performances of UHMWP modified asphalt were better than that of cross-linked UHMWP modified asphalt. As the UHMWP content increases, the high temperature performance of asphalt improves significantly. The rut factor of UHMWP-6 is 79.88% higher than that of UHMWP-4 at 70 ℃. On account of performance and cost, the recommended UHMWP content is 6%. The UHMWP is evenly bound by asphalt and has excellent compatibility. The content of UHMWP has a little effect on the phase change of asphalt. UHMWP mixtures have excellent mechanical performance, and their dynamic modulus reaches 21835 MPa at 15 ℃ and 10 Hz. As the temperature rises, the sensitivity of the dynamic modulus to frequency changes increases.