Effect of replacement of limestone mineral powder with fly ash and direct coal liquefaction residue on the rheological properties of asphalt mastic

Fly ash (FA) and direct coal liquefaction residue (DCLR) are coal-based industrial solid waste. Their unreasonable disposal has brought enormous economic, resource and environmental pressures. An effective treatment method is urgently needed. This study used FA and DCLR as fillers to replace limestone mineral powder (LP). The rheological properties of their corresponding asphalt mastics were evaluated by conventional performance tests and DSR tests. The effect of different properties of fillers on the rheological properties of mastic was revealed through finite element simulation. The test results show that FA and DCLR improve the viscosity, rutting resistance, elasticity and permanent deformation resistance of asphalt mastic, and reduce the temperature sensitivity. The improvement effect of FA is the most significant. The simulation results show that particle size and shape of filler affect the rheological properties and temperature sensitivity of asphalt mastic to different degrees respectively, and the filler particle size is the dominant factor.