Assessment of durability characteristics in masonry cement mortar incorporating raw ceramic polishing sludge

This study evaluates the durability performance of masonry cement mortar incorporating raw ceramic polishing sludge (CPS), an industrial by-product generated in large quantities during tile manufacturing. CPS partially replaced ordinary Portland cement (OPC) at levels ranging from 10 % to 50 %. Durability properties, including water absorption, drying shrinkage, chloride permeability, and resistance to sulfuric acid attack, were thoroughly investigated. Results showed a significant decrease in water absorption and porosity with increasing CPS content, reaching 3.5 % and 7.2 % at 50 % CPS, compared to 6.2 % and 12.7 % in the control mix, respectively. Chloride permeability dramatically improved, dropping from 6340C (high) in control to 500C (very low) at 50 % CPS, indicating a notably refined pore structure. Furthermore, CPS-modified mortars exhibited slightly higher drying shrinkage than the control, particularly at high replacement levels. The acid resistance exhibited interesting results as well. The weight loss study shows clear improvement, especially at short exposure periods (4 weeks), with only 2.7 % weight loss at 50 % CPS compared to 23.3 % for the control mix. However, the strength loss and cross-section studies, particularly at long-term exposure (24 weeks), revealed that the incorporation of CPS up to 50 % shows similar acid resistance to the control. Despite this, CPS-modified mortars demonstrated enhanced durability in several aspects and improved resistance to environmental deterioration, particularly in short-to medium-term exposure conditions. Furthermore, a cradle-to-site embodied carbon analysis demonstrated that replacing 30 %–50 % of cement with CPS can reduce the mortar's carbon footprint by up to 48 %, highlighting the significant environmental benefits of CPS utilization alongside its technical performance. These findings confirm the feasibility of using CPS as a sustainable supplementary cementitious material in masonry mortar to enhance resistance against environmental deterioration.