Robustness of self-compacting concrete containing waste foundry sand and metakaolin: A sustainable approach

Waste foundry sand (WFS) is a solid waste generated from the metal casting industries around the world, problem of its disposal and utilization are burgeoning universally. WFS is termed as a hazardous material due to the presence of organic and inorganic materials that are capable of contaminating the environment and can cause serious health issues. The study aims to re-utilize WFS in large volumes in concrete as a fine aggregate. The major impediment in the production of self-compacting concrete (SCC) is the robustness of concrete mixture. To study the effect of WFS on the robustness of SCC, six different mixtures were prepared having WFS up to 50 % at regular intervals of 10 % employing metakaolin as a substitute for cement at a constant ratio. It was revealed that the incorporation of WFS improved the robustness behavior of SCC, despite the change of ±10 L/m³ water dosage in SCC mixtures, all the mixes were observed falling in the same classes. Incorporation of 40 % WFS increased compressive strength by 17.2 % relative to control concrete at 56 days curing ages. The findings of the study suggest that WFS can be used in large volumes for the development of SCC without compromising its properties.