Geopolymer binders containing construction and demolition waste

The impact of global carbon emissions has resulted in increased demand and reduced reserves of supplementary cementitious materials. Thus, the need for additional precursors in geopolymer binders has pushed researchers to seek new alternatives such as the reutilizing of construction and demolition wastes (CDWs), especially those shown to contain high silica and alumina. This chapter presents a review of the use of CDWs, namely brick, ceramic, concrete and glass materials as precursors in geopolymer binders. Most of the literature identifies the viability of using CDWs through conventional geopolymerization methods, while involved chemical and physical factors can be controlled in order to obtain an optimum geopolymer mixture. Rheological behavior, compressive strength, and efflorescence formation of CDW-based geopolymers are found to be related not only to the degree of alkalinity and the silica modulus of alkaline silicate solutions, but also to the specific SiO₂/Al₂O₃, Na₂O/SiO₂, and Na₂O/Al₂O₃ ratios of CDW precursors.