The recycling of construction solid waste should take the road of green "dismantling" at the source

Xiao Jianzhuang, director of the Department of Architectural Engineering and director of the Green Construction Research Center of the School of Civil Engineering, Tongji University, has long been engaged in the research of basic theory, key technology and industrial application of construction solid waste recycling and recycled concrete. Recently, in an interview with this reporter, he called for the green "dismantling" of construction solid waste resource utilization from the source, through the advance classification and orderly and low-damage dismantling of building components, improve the feasibility of the overall reuse of old components, reduce the impact of noise, dust, vibration and other impacts on the environment in the construction process, and classify and transport the construction solid waste that is mixed with multiple components and difficult to use as a whole at the dismantling site for the first time, so as to better realize the high value-added utilization of construction solid waste.

Construction solid waste, also known as construction waste, refers to the construction waste generated due to man-made or natural disasters in the project.

"In the early days, solid waste was mainly made of natural materials such as stone, earth, and wood, and it was easy to return to nature. After the reform and opening up, a large number of artificial materials such as concrete, steel, bricks, glass, and plastics were applied to buildings, and it became more and more difficult to return to nature. Xiao Jianzhuang pointed out that at present, China mainly uses two ways to deal with construction solid waste, one is to transport construction waste to the local construction waste elimination site, and then carry out recycling, landfill or incineration treatment; From less than 5% in the past to 30% today, China's construction solid waste recycling has achieved a very big leap. However, as the country with the largest number of new buildings in the world every year, the treatment of construction solid waste in many places in China is still dominated by accumulation and landfill. Long-term accumulation and landfill will occupy land resources and pollute soil and water bodies, and construction waste accumulated outdoors will also pollute the air due to dust.

"If in the past, there was a need to solve construction solid waste first, and people used the simple way of 'going downstream' to deal with construction solid waste. Then, it is time to take the road of industrialization development and transform it into a development idea of 'going against the current'. Xiao Jianzhuang said that the so-called "against the current" refers to the resource utilization of construction solid waste must rise to the national strategy, according to the needs of the society and the industry, according to local conditions, the top-level design of resource paths, low-carbon products and green construction technology. Because natural resources are limited, with the increasing scarcity of domestic sand and gravel resources, as well as the proposal of the "double carbon" goal, the building materials industry will inevitably take a low-carbon development path, for which the industry and enterprises need to make great efforts.

"In the future, if people completely change the traditional concept of 'only new is the best' and use recycled building materials as fashion, it will be the best period for the development of construction solid waste. Xiao Jianzhuang said.

In addition to conceptual issues, safety issues are also one of the reasons why construction solid waste products are difficult to be accepted by the market. In this regard, Xiao Jianzhuang pointed out that professional problems must be handed over to professional people. In terms of the resource utilization of construction solid waste, great progress has been made in both standard formulation and technological development over the years.

According to statistics, under the joint promotion of the research team and a number of enterprises, the key technology of construction solid waste recycling has been promoted and applied in 25 provinces, autonomous regions and municipalities directly under the central government, and more than 80 construction solid waste resource production lines have been built, and the first recycled concrete frame multi-layer structure and the first recycled concrete frame-shear high-rise structure have been built in China. In particular, Shanghai and other places have encouraged or even forced the use of recycled aggregates, which has promoted a significant increase in the recycling rate of construction solid waste such as waste concrete, and practiced the "two mountains" concept and the "double carbon" strategy, with significant social and environmental benefits.

"On the other hand, these materials have been used for many years and should be more reassuring from a safety point of view. Xiao Jianzhuang said that the recycled building materials produced from construction solid waste have been baptized by time, reasonably designed and constructed, and then reused in buildings, and their safety is not to be worried at all. In addition, considering the whole life cycle, the transportation, processing and storage costs of recycled aggregates will be greatly reduced, which not only reduces costs, but also exerts carbon reduction power for the realization of the "double carbon" goal.

With the increasing emission of construction solid waste and China's increasing attention to the treatment of construction solid waste, Xiao Jianzhuang suggested that in the process of promoting construction solid waste recycling products, government departments should first use recycled building materials on a large scale, such as office buildings, libraries, exhibition halls and other public buildings, can use recycled concrete. This will not only give people a deeper understanding of green construction,