Study on performance enhancement of self-compacting concrete incorporating waste foundry sand

•Characterisation of waste foundry sand using XRD, TGA-DTG and SEM.•Utilisation of waste foundry sand for natural fine aggregate replacement.•Fresh and hardened properties of self-compacting concrete containing waste foundry sand.•Water permeability and sorptivity using autoclam apparatus. Large amounts of waste foundry sand (WFS) is being generated worldwide every year and it is necessary to re-use it for valuable cause. WFS is reported suitable up to a certain extent for replacement of fine aggregate in concrete. Answering the doubt on the issue of workability and durability properties can enhance its potential use. This study investigates the usability of waste foundry sand in self-compacting concrete (SCC). Fine aggregate was replaced with WFS with ratios ranging from 0 to 40%. The properties of WFS were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray fluorescence (XRF) methods. The effect of WFS was observed for the workability, mechanical behaviour and durability of the resulting SCC. The WFS showed distinct effects on workability with each level of replacement. At 90 days, SCC containing 10% WFS showed better mechanical and durability properties as compared to the control mix. Beyond 10% replacement level, strength and durability of concrete specimens started to show degradation. But WFS was observed as an excellent alternative for reducing the segregation especially in SCC. SCC with up to 20% WFS also showed acceptable levels of key performance parameters.