Abstract

The escalating cost of cement in Nigeria, coupled with the environmental hazards posed by improper disposal of calcium carbide waste (CCW) – a byproduct of acetylene gas production has necessitated the search for sustainable and cost-effective alternatives in construction materials. This study investigated the feasibility of partially replacing Ordinary Portland Cement (OPC) with calcium carbide waste as a supplementary cementitious material in concrete production. The research aimed to evaluate the effects of CCW on the workability and compressive strength of concrete when used as partial replacement for cement at 0%, 5%, 10%, 15%, and 20% by weight. A mix ratio of 1:2:4 (cement + CCW : sand : granite) with a water-cement ratio of 0.45 was adopted. Fresh concrete properties were assessed using the slump test, while compressive strength was determined at 7, 14, 21, and 28 days using 150 mm cubes cured in water. Results showed that workability decreased slightly with increasing CCW content due to the high fineness and water absorption tendency of the waste. Compressive strength also reduced progressively with higher replacement levels. The control mix (0% CCW) achieved a 28-day strength of 24.0 N/mm², while mixes with 5%, 10%, 15%, and 20% CCW recorded 21.3 N/mm², 18.6 N/mm², 15.5 N/mm², and 13.7 N/mm² respectively. Although all CCW-modified concretes exhibited lower strength than the control, the 5% and 10% replacement levels showed acceptable performance for non-structural and semi-structural applications. The study concludes that calcium carbide waste can be effectively utilized as a partial cement replacement up to 10% without significantly compromising strength, thereby offering a sustainable pathway for waste valorization, reduction in cement consumption, lowering of construction costs, and mitigation of environmental pollution associated with indiscriminate CCW disposal. It is recommended that 5–10% CCW replacement be adopted in low-to-medium strength concrete productions, especially in cost-sensitive and eco-conscious projects, with the use of superplasticizers to improve workability where necessary