High proportion warm mix asphalt regeneration technology

The expressions of "actively promoting the application of warm mix asphalt" and "promoting the resource utilization of waste road surfaces and asphalt..." can be seen that in the context of carbon peak shaving and carbon neutrality, the promotion and application of green low-carbon asphalt technology has risen to the national level. The best process to perfectly combine warm mix technology with asphalt recycling technology is the factory wide warm mix recycling technology with a large proportion of old material content.
1. Current status of heat recovery technology for power plant mixtures
Factory mixed heat recovery technology is a construction method that involves grinding, excavating, and centrally crushing old asphalt pavement before transporting it back to the mixing plant. According to the quality requirements of different levels of pavement, determine the proportion of old asphalt mixture, recycling agent, new asphalt, new aggregate, and other materials, and then mix them in the mixing plant to form a new mixture for the paving of asphalt pavement. The plant mixed thermal regeneration technology is suitable for the construction process of cold milling and hot paving of road surfaces. It can not only be used to repair the upper, middle, and lower layers of asphalt pavement, but also to reinforce the base and roadbed. At the same time, it has good adaptability and is suitable for repairing various types of asphalt pavement damage.
After scientific mix design, the performance of plant mixed hot recycled asphalt mixture has reached no lower than the technical indicators of new material mixed asphalt mixture, and the road performance meets the requirements of high-end pavement use; The grinding materials generated in highway or urban road maintenance projects can be recycled and used for the paving of the lower and even upper layers of asphalt pavement, maximizing the economic value of asphalt concrete waste.
In traditional factory mixed hot recycled mixtures, 15% to 30% recycled asphalt mixture (RAP) can be added. It is generally believed that increasing the amount of RAP is difficult to ensure the performance of recycled materials. Most mixed heat recovery equipment in factories find it difficult to achieve a high proportion of old materials while ensuring production efficiency and the performance of recycled mixtures. The main reasons are analyzed as follows:
1) The heating temperature of new stone should not be too high, otherwise it may indirectly lead to the threat of secondary aging of old asphalt in RAP materials;
2) The heating temperature of the old material should not be too high, as well as the problem of asphalt aging and adhesion with the heating drum in the old material;
3) Excessive addition of old materials will reduce the performance of the mixture;
4) Insufficient emission temperature may lead to difficulties in road compaction, ultimately threatening the water stability and fatigue performance of recycled roads.