Influence of multi-stage infrared heating on the efficiency and uniformity of asphalt pavement hot in-place recycling

To enhance heating uniformity and efficiency in the hot in-place recycling process of asphalt pavements, a multi-stage infrared intermittent heating method is developed through the creation of a physical and mathematical model for collaborative heating, analyzed using the finite element simulation software. This method is compared with a traditional single-step heating approach, with a focus on evaluating heating effects under various parameter configurations. Findings indicate that continuous and single-step intermittent infrared heating can cause asphalt pavement ignition and coking, resulting in severe asphalt aging. In contrast, multi-stage intermittent heating reduces maximum pavement surface temperatures as quenching intervals increase, though at the cost of prolonged total construction time and reduced heating efficiency. For two-step intermittent heating, a consistent cyclic heating period lowers the peak pavement temperature and reduces the heating time but significantly lengthens the total construction duration, thus impacting the overall efficiency. When assessing the construction quality, heating rate, efficiency, and energy consumption, the multi-stage intermittent heating method 1 demonstrates superiority over alternative approaches.