Life cycle assessment of three typical recycled products from construction and demolition waste

Environmental issues caused by the disposal of construction and demolition waste (CDW) is a worldwide problem. However, current studies lack a unified assessment of the reuse of CDW for quantifying the benefits in terms of the environment, economy, and carbon emissions. This study conducts a life cycle assessment on three typical recycled products manufactured from CDW: masonry bricks, permeable bricks, and thermal insulation blocks. The functional unit is 1 ton of CDW utilisation, and the system boundary is "cradle to gate". The results indicate that the freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity, and human noncarcinogenic toxicity are the key categories of environmental impact. The mixing process is the key impact process, which accounts for more than 70% of each key environmental impact category. The cement and adhesive glue are the key impact materials. When considering the benefits of construction waste replacing traditional building materials, CDW recycled products can achieve significant environmental benefits and carbon reduction effects, which is decreased by at least 1.3 of normalised environmental impact and 15.6 kg CO2e under per functional unit.