WasteReBuilt – a circular approach to transform waste sand into resource for the built environment

Linking the cast metal industry and concrete production sector to divert waste sand from landfill.

By applying the principles of circular economy, WasteReBuilt sought to demonstrate that waste foundry sand from the cast metal industry could replace up to 100% of the virgin sand currently used to make concrete.

Working with Weir Group Ltd and Dragon Alfa Cement Ltd, this project built on previous pilot studies by the School of Engineering which showed that the use of up to 100% waste foundry sand in cement mortar complied with regulatory standards and that no hazardous elements were leached out at maturity. In addition, there were indications that the use of waste foundry sand improved the structural performance of cement products.

The WasteReBuilt team advanced this research in two main ways:

• mapping of waste foundry sand composition against foundry locations and casting activities to enable detailed comparison with conventional fine aggregate sand. This mapping is now available under open access policy, allowing other industries to use waste foundry sand within their processes, diverting further waste from landfill
• replacing fine aggregate sand in concrete with waste foundry sand at ratios of up to 100%. Testing these concrete samples for strength, durability and any potential leaching of contaminants

WasteReBuilt involved industry experts and policymakers with the aim of influencing existing policies on building materials’ regulation and design. Stakeholders were engaged through online surveys and discussions in the initial stages of the project and invited to a final workshop which produced a report evidencing the technical and environmental benefits.

The project has provided the UK government, academics and industry experts with evidence-based and users-based briefs to influence policy decisions in this field, and increase awareness and impact.

Moving forward, the team will work with key industry partners through a knowledge transfer partnership or industrial PhD scholarship to design and develop a real-scale site trial to further test the efficacy of the materials produced.