Numerical simulation analysis on multi-layer low-temperature heating method of asphalt pavement in hot in-place recycling沥青路面就地热再生多层低温加热方法的数值仿真

Asphalt mixture pavement reheating is one of the important steps in hot in-place recycling (HIR). To improve the heating speed of asphalt pavement in HIR, based on the numerical analysis model of asphalt mixture heating process, a new multi-layer low-temperature heating method (MLHM) was proposed. Considering input heat flux, the thermal capacity and thermal resistance of asphalt mixture, the heat transfer model was established based on energy conservation law. By heating the asphalt mixture in layers, it changes the situation that the heat energy can only be input from the upper surface of the asphalt mixture pavement. Through the simulation of the heating method of asphalt mixture in the existing technology, the result shows that the existing heating methods lead to serious aging or charring of the asphalt mixture. By MLHM, the upper and the bottom of the asphalt mixture are heated at the same time, and the heating temperature is lower than other heat methods, which not only reduces the heating thickness and increases the heating area of the asphalt mixture pavement, but also improves the heating speed, saves the energy resource and ensures the heating quality. Especially, by MLHM, the heating uniformity is better and speed is faster.