A state-of-the-art review of Waste Foundry Sand concrete from an optimisation perspective

Waste Foundry Sand (WFS), a by-product of the cast metal industry is produced in quantities exceeding 100 million tons annually. Being a high-quality silica sand, it poses a potential solution for reuse within concrete as a fine aggregate replacement; simultaneously addressing the increasingly critical issue of foundry waste generation and mitigating the overextraction of natural aggregates for concrete production in line with United Nations Sustainable Development Goals. It is widely understood that partial WFS substitution as a fine aggregate within concrete is not only acceptable but often beneficial, however the variability in the properties of WFS concrete has yet to be systematically tracked and categorised. This state-of the-art-review provides a succinct and detailed assessment of the typical impact of WFS on concrete performance, highlighting variability in properties, and recent advancements for optimisation. Analysis of the lesser examined facets, such as WFS treatment and combination with supplementary cementitious materials is undertaken to provide a robust methodology for WFS concrete optimisation via effective research collation and impact categorisation. Existing studies on long-term durability, and life cycle assessment in terms of both environment and economics, are highlighted as lacking comprehensive insight and thus create a framework for future research.