Analysis of the Influence of ISR with TiO₂ Addition on the Compressive Strength and Durability of Structural Self-Compacting Concrete Associated with Porosity

Resumo

In the contemporary global landscape, efforts to reduce energy consumption and mitigate the carbon footprint associated with products and human activities have intensified, with the construction industry emerging as one of the most environmentally impactful sectors due to its substantial consumption of natural resources and significant waste generation. Among the sustainable strategies under investigation, the reuse of industrial or mining residues through their incorporation into construction materials has gained particular relevance. Within this framework, the present study evaluates the utilization of industrial solid residue (ISR) generated during TiO₂ extraction for pigment production as an additive in cementitious matrices, aiming both to ensure the environmentally responsible disposal of this waste and to harness the photocatalytic potential of the residual TiO₂. Specifically, the research investigates the incorporation of 15% ISR into structural self-compacting concrete (fck ≥ 30 MPa), assessing its influence on key physical and mechanical properties, with emphasis on apparent porosity, water absorption, and axial compressive strength. Experimental results revealed marked increases in water absorption (12.03% for ISR vs. 6.73% for REF), void index (24.23% vs. 14.56%), and capillary absorption (1.71 g/cm² vs. 0.86 g/cm²), alongside a reduction in compressive strength (31.32 MPa vs. 32.61 MPa). These findings indicate that ISR incorporation significantly modifies the concrete microstructure, promoting greater capillary pore formation and diminishing mechanical performance. While the resulting material complies with applicable technical standards, the observed microstructural changes underscore the need for further durability investigations to fully ascertain the long-term implications for service life and structural performance.