Experts talk about the development and application of cold recycling technology for asphalt pavement

Nowadays, in the field of road maintenance, cold recycling construction technology is popular at home and abroad due to economic and environmental advantages. At the recent Wirtgen Foshan Opening Ceremony and Technical Festival, Mr. Li Hao, general manager and industry expert of Jiangsu Youlu Transportation Technology Co., Ltd., described the development and application of cold recycling technology for asphalt pavement. Speeding up the recycling of road pavement materials, realizing the broad prospects of green conservation transformation, and its widespread application in China, he also pointed out that Wirtgen's post-discharge 3800 CR machine is a new trend in the industry.

Industry expert Mr. Li Hao

Cold recycling technology has broad application prospects

The cold recycling technology uses cold-recycling special machinery at normal temperature, continuously completes the milling and crushing of the old pavement structural layer, adding recycled materials, mixing, paving, rolling and other operations, and re-forms the structural layer with certain bearing capacity. A relatively mature green road maintenance and transformation technology has many advantages such as simplifying construction process, saving materials, shortening construction period and reducing cost.

According to Mr. Li Hao, from 1998, Wirtgen's first local cold recycling machine WR 2500 settled in Hebei, and by 2006 Wirtgen's first plant mixed cold recycling machine KMA 200 settled in Xi'an, Shaanxi, and then to Wirtgen in 2013. The rear-discharge crawler type cold regenerator 3800 CR was introduced, and the cold regenerative technology has been widely used in all other provinces and cities except Tibet. And there is still a lot of room for development in the future.

In this regard, Mr. Li Hao gave two sets of data. First, according to the documents of the Ministry of Transport, in 2020, the recycling rate of old road pavement in the country reached more than 90%, of which the recycling rate of the old road pavement was 95%, and the recycling rate of the old road pavement was 85%. The second is: about 160 million tons of waste pavement materials produced by the large and medium-sized highways in the national trunk highways, and the recycling rate of pavement materials is only about 30%. In his view, cold recycling technology is an inevitable requirement for accelerating the recycling of road pavement materials and implementing green maintenance production.

In order to verify this point of view, Mr. Li Hao vividly explained the application and effectiveness of cold recycling technology in road maintenance, renovation and expansion through many typical examples. For example, in Shenyang, Liaoning, Shanxi Datong G208 National Road, Shaanxi Shangluo G312 National Road, etc., the full-depth cement is coldly regenerated on site, which improves the semi-rigid base strength of the road. In the Guangdong Huihe Expressway and the Guangzhou Airport Expressway along the north, the foamed asphalt cold regeneration solved the problem of reflection cracks. In Yingkou and Huangshan to Luozhou section of the South Third Ring Road of Fuzhou City, the combination of cement and foam plant mixing has been effective in optimizing the structure of cold recycled pavement. The reconstruction and expansion of the trunk highways such as Shensi Expressway, Fokai Expressway and Haikou Ring Expressway have realized the near-utilization of resources through the foam asphalt plant. In addition, in Guangdong, Hainan, Zhejiang Taizhou, and other places, cold recycling technology is also applied to composite pavement transformation, effectively optimizing the pavement performance.

3800 CR machine is fast, efficient, energy saving and environmentally friendly

On the day of the speech, Mr. Li Hao also expressed his own opinions on the new trend of cold recycling technology development. He believes that Wirtgen's local cold recycling machine 3800 CR can regenerate the entire lane of 3.8m wide at one time. The undercut operation can also optimize material grading and deliver the regenerated material directly to the paver hopper to eliminate material non-uniformity. It can be paved with an ideal cross slope and is a new pioneer and a future trend for cold recycling technology.

Wirtgen in situ cold recycling machine 3800 CR

It is understood that the 3800 CR design has deeper milling depth and faster working speed, so it is more productive and can meet the construction efficiency requirements of various roads and urban roads. In addition to spraying emulsified asphalt or cement slurry, it can also spray foam asphalt with better performance and more promising applications, and complete the precise addition and mixing of foamed asphalt to obtain high quality and uniform recycled mixture. The cold recycled mixture is in full compliance with the quality specifications for the underlying materials. It is 100% recycled and reused. It not only saves energy and protects the environment, but also significantly reduces the construction cost of the construction side.

Wirtgen in situ cold recycling machine 3800 CR

The Wirtgen 3800 CR has been successfully applied. In June 2017, it was used in conjunction with the VÖGELE Super 1880-3 L paver, and was cold-recycled on site in Xinyi Road, Beijing, and paved. In this project, the Wirtgen 3800 CR, with its excellent stability, first mills the broken asphalt pavement and then mixes the granulated material with 1.5% pre-spreaded cement. During the post-discharging work, the Wirtgen 3800 CR travels in the opposite direction, milling the damaged asphalt pavement in the following cut mode and transporting the regenerated material to the paver. Cooperating with the VÖGELE paver to regenerate the entire lane at one time, the construction efficiency is high, and the construction effect fully meets the project requirements. (This article is from Wirtgen China)