Influences of fine waste foundry sand from the automobile engine-part casting process and water-cementitious ratio on the properties of concrete: A new approach to use of a partial cement replacement material

Abstract

This research was conducted to study the utilization of fine waste foundry sand (FWFS) produced by the automobile engine-part casting process as a partial cement replacement material in the production of concrete. The tested contents of cementitious material (ordinary (Type I) Portland cement (OPC) plus FWFS) were 350 and 450 kg/m3, the tested water-cementitious material ratios (w/c) were 0.35, 0.45, and 0.55, and the percentage replacements of FWFS in the OPC were 10, 20, 30, and 40 wt%. The evaluated fresh properties included the unit weight, initial slump, late slump and setting times. Furthermore, the hardened properties were tested, including the compressive and splitting tensile strengths, modulus of elasticity, and the resistance of the concrete to chemical attack by a 5% sodium sulfate (Na2SO4) solution and a 1% sulfuric acid (H2SO4) solution. The experimental results indicated that, with an increase in the FWFS replacement percentage, the unit weight of fresh concrete and initial slump decreased, while the late slump, initial and final setting times increased. Importantly, increasing the FWFS replacement in OPC slightly decreased the compressive and splitting tensile strengths and the concrete's 28-day modulus of elasticity. The chemical resistance results indicated that, following immersion in Na2SO4 or H2SO4, the concrete mixed with FWFS exhibited less corrosion than the conventional concrete (0% FWFS replacement). Additionally, the mass loss was low when the w/c ratios decreased and the percentage replacement of FWFS increased.