Properties of concrete containing fungal treated waste foundry sand

Waste foundry sands represent the highest amount of solid wastes generated by foundries. The high cost of land-filling and the potential uses of waste foundry sand in construction purposes have prompted research into their beneficial reuse. For high-performance construction materials microbial (bacteria/fungi) modified concrete has become an important area of research. This study investigates the effects of incorporating fungal treated waste foundry sand (WFS) on concrete. Results present the effect of Aspergillus spp. on compressive strength, water absorption and porosity of concrete containing waste foundry sand. The study shows that 15.6% increase in compressive strength of concrete after 28 days was achieved with the addition of fungal (Aspergillus spp.) treated 20% WFS containing concrete and also shows decrease in water absorption (68.8%) and porosity (45.9%). X-ray diffraction (XRD) results suggest that fungal culture (Aspergillus spp.) is capable to form good C–S–H gel than untreated concrete containing WFS, which shows that Aspergillus spp. increase the ability of cement to react properly with foundry sand and hence due to which C–S–H gel formation increases. Silica present in WFS is consumed to form C–S–H gel, which in turn hardened the fungal treated waste foundry sand containing concrete.