Construction waste mixed with reinforced concrete is sorted, screened and crushed in situ, and becomes a variety of building materials that can be recycled. On a construction site in Shendu Village, Xi'an International Port Area, nearly 30,000 cubic meters of construction waste is no longer considered as waste disposal for landfill, but has become a resource and has become a place of use.

 

On January 12, the reporter walked into the construction site and saw a construction machine on a vacant ground crushing the dismantled construction waste and transferring it to another sifting machine. The treated pulverized material was transported to three spit through three conveyor belts. At the material port, three kinds of regenerated aggregates of fine aggregate, medium aggregate and coarse aggregate are respectively spit out, and construction waste becomes a building material for laying roads and making recycled bricks and concrete aggregates.

 

It is the technology of solid waste separation project in Shaanxi Province jointly developed by Shaanxi Provincial Construction Research Institute and Shaanxi Zhongke Solid Waste Separation Equipment Research Institute to turn construction waste into waste. “After our treatment, the recycling rate of construction waste reached 95%, which improved the resource utilization rate and reduced environmental pollution,” said Yu Jinquan, president of Shaanxi Zhongke Solid Waste Separation Equipment Research Institute.

 

It is understood that the recycling of construction waste is becoming a new topic. In Shaanxi Province, 50 million cubic meters of construction waste will be produced in one year. In Xi'an alone, there are 20 million cubic meters. In the past, most of them were disposed of by landfill, which not only occupied the land, but also caused pollution to the environment, soil and water. In addition, as the pace of urban expansion continues to accelerate, many formal construction landfills have become saturated. This new technology, which is not landfilled, non-polluted, and not wasted, is undoubtedly a good choice for solving the construction waste.

 

Compared to traditional treatment methods, construction waste is also more environmentally friendly. Calculated according to the construction waste of 30,000 cubic meters, it needs to be landfilled at least 5 mu according to the 10 m deep pit. If 20 million cubic meters of construction waste is to be disposed of in Xi'an, only 3,000 mu of land will be needed to fill the construction waste every year. . "When all the garbage has been cleared, it will take 4 million mucks to run 4 million times to solve it. Recycling can avoid these problems." Yu Jinquan said.

 

However, is the strength of the recycled aggregate prepared by the crushing and screening process the same as the natural raw materials?

 

In a test book provided by a third-party certification body, the reporter saw that the recycled aggregate formed by the construction waste has nearly the hardness and pressure resistance of the granite in terms of water absorption, cylinder strength and bulk density.

 

“In the past, there was no sorting technology for the treatment of construction waste, and the utilization efficiency was low. Now we have selected bricks, mortar, concrete, etc., so that different materials can be used to the best of our ability.” I have been involved in the research project of Shaanxi Zhongke Solid Waste Separation Equipment Research Institute. Zhang Wei, from the School of Materials Science and Technology of Xi'an University of Architecture and Technology, said that construction waste is treated, in which the mortar can replace 100% of natural sand after removing powder; brick can replace fly ash; aggregate formed by crushing concrete can replace stone. “Recycled aggregates have reached the second-class recycled aggregate standard. Combined with the mixing technology developed by us, we can use it in a certain proportion with natural aggregates. It can be used in building construction. Shanghai has already used recycled aggregates and natural materials. The building constructed with a certain proportion of aggregates," Zhang Wei said.

 

It is understood that Shaanxi introduced the “Shaanxi Green Building Action Implementation Plan” in 2013, and proposed to implement renewable energy utilization to specific projects. Today, Yu Jinquan is conducting experiments related to the technical standards for the use of recycled aggregates.

 

Considering that the technology has been transformed and utilized in Beijing and Chengdu, as the only unit in Shaanxi that is currently recycling construction waste, Yu Jinquan hopes that Shaanxi can have more such projects. “Compared with 100 yuan of natural stone, 100 meters of recycled aggregates, the main advantage is that the cost is low. One cubic meter is only 60 yuan. If it can be widely promoted, it can also reduce the demand for mountain quarrying.” Yu Jinquan said.