Estimating construction and demolition waste in the building sector in China: Towards the end of the century

Amid China's rapid urbanization and economic growth, increasing construction and demolition waste (CDW) has become a critical environmental and management challenge. In the present study, we introduce a dynamic recursive-based CDW assessment model designed to systematically track and analyze the origins, distribution, and composition of CDW across China. Our results show that China is projected to generate 224.08 billion tonnes (Bt) of CDW from 2000 to 2100, mostly gravel (34.15%), sand (30.08%), and brick/tile (14.37%). Additionally, the primary source of CDW generation will shift from rural to urban public and commercial (P&C) buildings. The proportion of metals such as steel in CDW is rapidly increasing, rising from 2.11% in 2000 to 17.66% in 2100. From 2020 to 2100, reducing material waste during the construction phase can decrease the amount of CDW by 6.88 Bt. Extending the building lifespan during the operation phase can further reduce the amount of CDW by 50.25 Bt. In comparison, implementing recycling strategies during the demolition phase can achieve the most significant reduction in the amount of CDW, with an estimated cumulative decrease of 151.25 Bt. The amounts of gravel, sand, and steel are anticipated to contribute the most to this reduction, accounting for 44.93%, 37.66%, and 8.8% of the total reduction in the amount of CDW, respectively.