Abstract / Summary
Rapid consumption of Portland cement (PC) in construction industry has environmental and economic challenges. To address these issues, this study investigates the valorisation of over-fired clay brick waste (OCBW), a manufacturing kiln by-product, as a supplementary cementitious material (SCM). PC was partially substituted with varying proportions of OCBW at 0, 5, 10, and 15% by weight to produce concrete mixtures of CC (control), BC5, BC10, and BC15, respectively. These mixtures were evaluated for strength, durability, hydration, microstructure, and radiation attenuation. OCBW characterization exhibited a high content of reactive silica, proper particle fineness, substantial amorphous phases, and remarkable antifungal activity, confirming its pozzolanic potential. Among the mixtures, BC10 attained optimal compressive and splitting tensile strengths approximately 10.30 and 10.50% higher than the CC, respectively. Moreover, BC10 achieved 33.30% reduction in chloride ion permeability, boosted resistance to acid and sulphate attack, and decreased water penetration depth. Additionally, it revealed a denser microstructure with an improved interfacial transition zone. A consistent enhancement was observed with OCBW incorporation at 10 and 15%, improving fast neutron attenuation by 10.70 and 22.60%, compared to CC, respectively. This improvement also extended to γ-ray attenuation, which increased by 8.10% at 10% OCBW; however, at 15% OCBW, this behavior was undermined, with attenuation decreasing by 8.30%. Overall, OCBW emerges as a promising eco-friendly and multifunctional SCM with potential applicability in medical and nuclear facilities, subject to further validation. Furthermore, a 10% replacement level offers an optimal balance of strength, durability, microstructural refinement, and radiation shielding with reduced PC consumption.