Abstract
The foundry industry in South Africa forms one of the greatest industries in the
manufacturing sector. It produces waste foundry sand (WFS) that ends up in landfill sites. Around
80% of the WFS could be utilized as a substitute for sand in concrete. The utilization of WFS will
benefit the industry, as raw materials (natural sand alternative) and energy are conserved, while costs
of disposal are lowered. Soil pollution, as well as water and air resources, will be minimized and
the foundries’ competitiveness will be improved. In this study, the physical and chemical properties
of five WFSs (two clays and three chemically bonded molding sands) from Gauteng, South Africa
were analyzed. The samples were investigated with a view to determine their conformity with
applicable engineering criteria when used as a replacement, to various extents, of the fine aggregate.
The main properties investigated included physical properties (particle gradation, moisture content,
un-compacted bulk density, specific gravity, loss on ignition, clay content, and fineness modulus)
and the chemical properties (X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron
microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), pH). The sands generally did not
meet the standards pertaining to grading requirements. However, the chemical test results showed
the composition of these sands to be comparable with results from other investigations and suitable
for use as a natural sand replacement in concrete.