Effects of Calcium Carbide Residue-Fly Ash Binder on Mechanical Properties of Concrete

This study investigated the use of two kinds of waste from landfills, calcium carbide residue and fly ash, as a low CO2 emission concrete binder. Calcium carbide residue is a by-product of an acetylene gas production process, and fly ash is a by-product of a thermal power plant. Ground calcium carbide residue (CR) was mixed with original fly ash (OF) or ground fly ash (GF) at a ratio of 30:70 by weight and was used as a binder to cast concrete without portland cement. The effects of fly ash finenesses and water to binder (W/B) ratios of CR-OF and CR-GF concretes on setting times, compressive strength, modulus of elasticity, and splitting tensile strength were investigated. The results indicated that CR-OF and CR-GF mixtures could not only be used as a new binder in concrete but could also help reduce environmental problems associated with CO2 emissions. Without the use of portland cement, CR-GF concrete yielded compressive strengths of 28.4 and 33.5 MPa at 28 and 90 days, respectively. In addition, lower W/B ratio and high fineness of fly ash produced higher compressive strength of the concrete. The hardened concretes produced from CR-OF and CR-GF mixtures had mechanical properties similar to those of control samples made from normal portland cement concrete.