During the continuous upgrading, renovation, maintenance, and repair of urban roads, large quantities of removed asphalt pavement material are discarded, not only occupying land resources but also causing enormous waste. However, these seemingly "useless" waste materials actually contain immense value and can be reused through scientific and rational technological means, opening a new chapter in resource recycling.
From both resource and environmental perspectives, the reuse of removed asphalt pavement is of profound significance. The main components of asphalt pavement materials include aggregates and asphalt. Aggregates are usually produced by crushing and processing various ores. In the current context of increasingly scarce natural resources, recycling them can reduce the mining of natural ores and protect the ecological environment. At the same time, if discarded asphalt pavement is disposed of arbitrarily, it not only occupies a large amount of land, but harmful substances may also seep into the soil and water bodies, causing environmental pollution. Realizing its recycling is an important measure to practice the concept of green development and promote sustainable development.
Currently, several mature and effective recycling technologies have been developed for removed asphalt pavement materials. On-site cold recycling technology plays a vital role in road maintenance due to its high efficiency and convenience. This technology involves milling the old asphalt pavement directly on-site, then adding emulsified asphalt, cement, water, and other materials. Through a series of processes including mixing, paving, and compaction, the old pavement material is given a "new lease on life." This technology is suitable for road sections with severe pavement damage but good subgrade conditions. It minimizes traffic disruption during construction, quickly improves pavement performance, and reduces maintenance costs.
Plant-mixed hot recycling technology focuses more on optimizing and improving the performance of recycled materials. The recycled old asphalt pavement material is transported to an asphalt mixing plant, where it undergoes crushing and screening. It is then mixed with new aggregates, asphalt, and additives in precise proportions and thoroughly stirred under heating conditions to produce recycled asphalt mixtures that meet stringent quality requirements. These recycled mixtures can be widely used in pavement repair and new construction projects for highways of various grades, effectively improving pavement quality and service life, and achieving efficient resource utilization while ensuring road performance.
Plant-mixed cold recycling technology also has unique advantages. Old asphalt pavement materials are transported back to the mixing plant for crushing and screening. Emulsified asphalt, foamed asphalt, or other cold binders, along with a suitable amount of water, are then added and mixed at room temperature to create a cold recycled mixture. This mixture is then transported to the construction site for paving and compaction. This technology is particularly suitable for the construction of road base and subbase layers, offering significant advantages such as energy saving, environmental protection, and low cost, providing an economical and environmentally friendly solution for road construction.
Furthermore, crushed old asphalt pavement materials can also be used as aggregate for road base layers. In this process, only a certain amount of cement, lime, and other binders need to be added, and after thorough mixing and compaction, a stable and reliable base structure can be formed. This application method is also suitable for new or reconstructed road base layer projects, greatly reducing project costs and achieving rational resource allocation.
The removed asphalt pavement is not truly waste, but rather "resources in the wrong place." Through continuous innovation and improvement of recycling technologies, we can not only reduce resource waste and environmental pollution but also inject new momentum for green development into the road construction industry. In the future, with the continuous advancement of technology, the removed asphalt pavement materials will undoubtedly play a role in more fields, contributing even more to the construction of a resource-saving and environmentally friendly society.