With the rapid development of my country's highway industry, asphalt pavement has been widely used. Road maintenance issues are becoming increasingly prominent. The recycling of old asphalt pavement materials has received attention from various countries in recent years. This article analyzes the practical significance and feasibility of hot asphalt recycling from an engineering practice perspective, and analyzes the key technologies of hot asphalt recycling.
The Importance of Hot Asphalt Recycling Technology
With the rapid development of asphalt pavement in my country's highway industry, the maintenance cost of asphalt pavement has increased, leading to research on asphalt pavement maintenance in various countries. The hot recycling of old asphalt pavement materials has attracted widespread attention from various countries for nearly half a century. Research on hot asphalt recycling technology has achieved significant economic benefits and practical significance. Hot recycling of old asphalt pavement can save most of the natural raw materials, conserve resources, and reduce the environmental pollution caused by old asphalt waste. Secondary recycling of old asphalt reduces maintenance costs, creates good economic benefits, and implements a sustainable development strategy. Hot asphalt recycling has broad application prospects.
In-situ Hot Recycling

Using specialized geothermal recycling equipment, the asphalt pavement is heated and milled. A certain amount of new asphalt and asphalt mixture are mixed locally, and then hot-mixed, packaged, and compressed. The proportion of newly added asphalt mixture is generally controlled within 30%.
In-situ thermal recycling is mainly a reverse repair method for pavements with intact old layers, minor damage, or low-grade pavements. This process is characterized by the ability to utilize large quantities of old materials. It ensures traffic flow while reducing costs, material usage, and transportation costs during the renovation process. It also has environmental value, preventing dust and meeting environmental protection requirements. However, this method is only suitable for pavement layer repair and is easily affected by seasonal weather.
Construction of In-situ Thermal Recycling
Before processing old asphalt concrete, whether using it as a base component or as an additive to new mixtures, old asphalt must be extracted and tested to determine the individual contents of asphalt and sand, and the gradient composition of the old asphalt. Key parameters of the old asphalt, such as viscosity, label, and actual oil content, must be determined. The reliability of the old material is determined through experimental analysis.
Characteristics of On-Site Hot Recycling Method
Asphalt hot recycling technology is an advanced technology. Its operation involves continuous processes such as on-site heating, loosening, mixing, paving, and compaction, resulting in significant economic and social benefits in terms of construction, economy, efficiency, speed, environmental protection, and cost savings.
Asphalt hot recycling can be used when the surface layer of asphalt pavement exhibits defects such as cracks, bleeding, wear, rutting, and potholes, or when its road performance has deteriorated, but the damage has not yet affected the base layer.