As the asphalt pavement ages, the pavement undergoes natural oxidation and heavy traffic loads, leading to a gradual acceleration of its deterioration. Consequently, a large amount of reclaimed asphalt mixture (RAP) is generated during maintenance and repair processes. The rational and efficient recycling of these materials has become a hot topic in current road construction. Foamed asphalt cold recycling technology, featuring stable technical performance of the finished material and relatively low production costs, has been gradually applied and promoted in the area of road maintenance in recent years. It boasts outstanding usage results, becoming the "new favorite" in the field of recycling. 

Foamed asphalt cold recycling technology involves injecting room-temperature water into hot asphalt, causing the asphalt to expand and form asphalt foam. The foam is mixed with RAP at a certain ratio, along with new aggregates, active fillers (such as cement and lime), and water, all at room temperature. Then the mixture is paved to form a pavement structural layer, which has a mechanism that lies between rigid and flexible bases, primarily suitable for use as an upper base layer or underlayment of asphalt pavement. The technology not only maximizes the "residual value" of old asphalt mixtures, promoting the circular reuse of old pavement materials, but also significantly reduces energy consumption in the exploitation of virgin aggregate resources, mitigates environmental pollution, therefore achieving the resourceful reuse of RAP and contributing to the low-carbon and green transformation of road maintenance.

1. Energy-saving and Eco-friendly: Only the heating of asphalt is required, no aggregates heating needed compared to hot-mix asphalt mixture production, thereby saving energy and reducing energy consumption. Additionally, this technology help consume plenty of RAP generated from asphalt pavement renovation, cutting down environmental pollution.

D&G Machinery in Action: As an industry and technology leader, D&G Machinery embraces bold experimentation and technological advancement. In 2021, through in-depth collaborative research with the Research Institute of Highway, Ministry of Transport, and extensive engineering practice validation, D&G Machinery launched a complete set of foamed asphalt cold recycling equipment (featuring a new continuous asphalt foaming device, patent No: ZL 2022 20853100.9), achieving exceptional usage results and user experiences.

The process of this equipment can also be applied to upgrade and transform existing aged water-stabilized mixing plants into continuous foamed asphalt cold recycling systems (with the option of supporting emulsified asphalt device). Currently, this upgrade has been successfully applied to various brands of water-stabilized mixing plant. For example, a customer in Jilin Province,China retrofitted a model 800 water-stabilized mixing plant of a domestic brand with an asphalt foaming device in 2023, upgrading it into a continuous emulsified asphalt cold recycling plant.

With an increasing need for road maintenance and higher requirements of environmental protection, there would be a broader development prospect for the foamed asphalt cold recycling technology. We believe this technology will witness further promotion and application in the following aspects: