Strength Properties of Concrete with Partial Utilization of South African Waste Foundry Sand

Abstract

The foundry industries incur a considerable cost in discarding Waste Foundry Sand (WFS) to landfill sites. In addition, the lifespan of landfill sites is decreasing due to increasing waste. Recycling the greater part of these wastes is the best environmental solution for resolving the waste disposal problem at landfill sites in South Africa. This paper presents a study on the properties of concrete with partial substitution of sand with WFS. The sand for the different concretes was substituted at either 30%, 70%, or 100% by mass with WFS at water/ cement ratios (w/c) of 0.4 and 0.6. The concrete properties with the various partial replacements of WFS, which were evaluated at the ages of 7 and 28 days, were compared with the relevant reference (control) mixes (containing 0% WFS). This research indicated that generally 30% was the optimum replacement of sand with WFS. However, for all the properties considered up to 70% WFS can effectively replace sand in concrete without significantly reducing the concrete’s strength properties (compared to the control samples). The incorporation of WFS in concrete can be used as an alternate building technology material in construction, hence contributing to sustainable development and circular economy.