Modeling and optimizing the properties of mortars based on natural pozzolan, silica sand, and recycled brick waste mixture design: A technical and environmental study

Environmental degradation is escalating due to increasing pollution caused by raw material depletion and the growing demand for concrete products. Manufacturing various building materials, particularly cement, contributes significantly to atmospheric carbon dioxide emissions. This study investigates the recycling of brick waste and diversifies natural resources in cement production to mitigate environmental damage and conserve natural resources. The study explores the synergistic effects in mortars prepared by substituting cement with brick waste, natural pozzolan, and silica sand, with a fixed substitution ratio of 20 %. The influence of these raw materials substitutes on the initial setting time and hardened state properties was assessed through compression, absorption by immersion and capillary water absorption. The results indicate that adding brick waste increases the initial setting time from 140 min to 160 min for Mix 3 to Mix 10. Incorporating pozzolan enhances compressive strength, immersion and capillary absorption with increases up to 21 %, 20.7 %, and 40 %, respectively, compared to the control mortar (CM). Statistical analysis shows that the proposed predicting models are effective and applicable since their correlation coefficients (R2) range between 0.91 and 0.99. Life cycle analysis (LCA) reveals that incorporating these materials reduces grinding energy and carbon dioxide (CO2) emissions during cement production and material transport.