Study on the properties and curing kinetics of high-performance polyurethane modified asphalt

Abstract To improve the road performance and deformation adaptability of steel bridge deck pavement materials under extreme temperature and heavy-load conditions, and to overcome the high cost and poor workability of traditional polyurethane-modified asphalt during high-temperature construction, a blocked polyurethane prepolymer was synthesized with ε-caprolactam as the blocking agent for producing high-performance polyurethane-modified asphalt. A systematic study was conducted on the microstructure, rheological properties, and curing kinetics of the asphalt modified with varying contents of the blocked polyurethane system. Results indicate that the incorporation of blocked polyurethane significantly enhances the high-temperature performance of the asphalt binder. Based on the Kissinger and Crane equations, the activation energy (Ea), pre-exponential factor, and reaction order of the curing reaction were calculated as 51.73 kJ/mol, 2.6×10 5 min −1 , and 0.89, respectively. The established curing kinetic equation offers a theoretical foundation for determining the appropriate construction window for blocked polyurethane asphalt.