Construction and demolition waste-based geopolymers for built-environment: An environmental sustainability assessment

In this study, the environmental sustainability assessment has been performed for producing geopolymer binders for 3-dimensional additive manufacturing (3D-AM). To substitute Portland cement, the technique utilizes building and demolition waste (CDW) [hollow brick (HB), red clay brick (RCB), roof tile (RT), and glass (G)] as a sustainable resource for geopolymers synthesis. A life cycle assessment aims to determine hotspots (relevant processes or raw materials) early in the product development process to enhance the entire process's environmental performance and evaluate the ecological impact of energy, water, and waste emissions. The CDW requires crushing, milling/grinding, and mixing using the input power to make the geopolymer binders. The life cycle impact assessment (LCIA) results show the environmental impacts to be 635 (kg CO₂ eq.), 5.06 (kg SO₂ eq.), 0.104 (kg N eq.), 3.14E-10 (kg N eq.), and 12.2 (CTUe.) for the global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), and Ecotox air respectively for 1 m³ of geopolymer binder produced.