Performance Evaluation of Cementitious Mortars Made with Ceramic Waste Powder and Calcium Carbide Residue

Reducing ordinary Portland cement (OPC) content through waste-derived binders can improve the resource efficiency of mortar and concrete. This study explores the effect of single and combined replacement of ordinary Portland cement (OPC) with ceramic waste powder (CWP) and calcium carbide residue (CCR), with the original contribution being the systematic mixture-design evaluation of a ternary OPC–CWP–CCR binder using mixture design and an integrated assessment of mechanical and durability-related performance. Ten mixes with varying mixture proportions were designed using the mixture design of experiments (DoE). Fresh and hardened properties were evaluated, including flowability, compressive strength, bulk resistivity, and water absorption tests up to 56 days, while chemical durability was assessed by exposure to 5% sulfuric acid. OPC replacement with CCR and CWP reduced early-age strength due to dilution; however, CWP-dominant blends exhibited late-age strength gain. The mixture containing 26.7% CWP and 6.7% CCR reached 44.7 MPa at 90 days and 406.7 Ω·m at 56 days and exhibited the lowest relative strength loss after sulfuric acid exposure (12.8%, versus 16.0% for the control). High CCR contents adversely affected workability, water absorption, strength, and acid resistance. CWP-dominant blends provided the best overall balance of performance and OPC reduction.