A state-of-the-art review of crushed urban waste glass used in OPC and AAMs (geopolymer): Progress and challenges

The global disposal of urban waste glass has been facing a great challenge while the glass products are still continuously produced annually. Discarding waste glass, a nonbiodegradable material, to landfills is not offering a sustainable management of this municipal solid waste. In recent years, against the backdrop of prevailing OPC-less or even OPC-free cementing materials, increasing attention has been paid to the application of waste glass powder (GP) in sustainable cement and concrete, since GP is rich in amorphous silica (∼70%). This paper provides a comprehensive review of GP used as the eco-supplementary cementitious material in ordinary Portland cement (OPC) and the precursor of alkali-activated materials (AAMs). The effect of GP on mechanical and durability properties of cementitious materials is systematically discussed. The review also includes the recent progress on measuring the reaction degree of GP and the prediction of hydration products by thermodynamic modelling. However, the related research on the durability of GP-based AAMs is limited, especially on the aspect of ASR expansion. In addition, the majority of published studies were based on laboratory-scale experiments. More case studies are required on the performances of real concrete structure containing GP.