Potential impact of calcium carbide residue on the fresh and hardened behavior of eco-friendly cement-based composites

The need to reduce both the ecological impact and construction costs has motivated the search for alternative binding materials that enhance the use of industrial by-products as supplementary cementitious materials (SCMs). This paper explores the utilization of calcium carbide residue (CCR) as an SCM to fabricate cement-based mortar, due to its abundant availability and environmental benefits. CCR, an end-of-life waste generated from producing gaseous acetylene, was harnessed to replace ordinary Portland cement (OPC) by 10, 20, 30, 40, and 50 %. The experimental program consists of parts: Firstly, the preliminary physicochemical and microanalysis characterization of CCR powder were investigated. Secondly, the fresh and hardened behavior of the fabricated mixtures were observed. Finally, the cost and environmental analysis were conducted to obtain a sustainability and cost-effective evaluation. The results proved that incorporating 10 % CCR boosts the hardened characteristics. In contrast, further upgrading the CCR content adversely affects the investigated responses. After 28 days, mortars incorporated with 10 and 50 % of CCR gave compressive strength of 31.6 and 20.4 MPa, respectively. Including 50 % CCR resulted in a maximum reduction in compressive strength of 35.4 and 29.6 % at 28 and 90 days of age. The cost and environmental analysis prove key advantages in lowering the equivalent embodied CO₂ emissions and the total cost of the mortar. The Incorporation of 10 % CCR lowered CO₂ emissions and cost by 9.6 and 6.8 %, respectively. Despite 10 % CCR enhancing the examined characteristics, the mixtures containing high levels of CCR satisfied the requirements of cement mortar for unit masonry.