SBS-PRM Composite Modified Asphalt Based on Physicochemical Spatial Crosslinking Structure

Abstract:

Based on the potential physicochemical spatial crosslinking properties of SBS modifier and polyurethane-precursor chemical modifier（PRM）， the SBS-PRM composite modified asphalt was prepared. The high viscosity characteristics of the asphalt samples were clarified by penetration， softening point， ductility， and dynamic viscosity test. Rheological characterization of modified asphalts was investigated using frequency sweep test， multiple stress creep recovery test， linear amplitude sweep test， and bending beam rheometer test. The physicochemical composite modification mechanism was explained using Fourier transform infrared spectroscopy， atomic force microscopy， and fluorescence microscopy. Finally， the pavement performance of asphalt mixtures was verified. The results show that PRM changes the molecular structure of asphalt through chemical reaction which contributes to improving the compatibility of SBS with asphalt. The formation of spatial crosslinked network structure enhances the viscosity， resistance to high-temperature permanent deformation， low-temperature cracking， and fatigue damage of asphalt. In addition， significant advantages are obtained in high temperature rutting resistance， low temperature cracking resistance， and moisture damage resistance of SMA-13 mixtures prepared with composite modified asphalt.

Key words:road engineering;physicochemical spatial crosslinking;polyurethane-precursor-based reactive modifier;pavement performance;modification mechanism