Multifunctional TiO₂-modified cement mortar: experimental investigation, machine learning prediction, and life cycle assessment

Abstract

TiO₂-modified cement mortar is a multifunctional construction material that enhances both mechanical performance and environmental remediation. This study investigated the photocatalytic activity, compressive strength, machine learning prediction, and life cycle assessment of cement mortars containing 0–12 wt% TiO₂. Photocatalytic performance was evaluated through the degradation of Reactive Blue 19 (RB19) dye under visible-light irradiation, while SEM, XRD, and FTIR analyses were used for material characterization. Random Forest (RF) and Extreme Gradient Boosting (XGBoost) models were developed to predict dye removal efficiency and compressive strength. The photocatalytic efficiency increased with TiO₂ content, reaching 87.13% RB19 removal within 60 min at 10 wt% TiO₂. Acidic conditions enhanced dye degradation, whereas higher dye concentrations reduced removal efficiency. Compressive strength increased to 23.4 MPa at 28 days with 6 wt% TiO₂, representing a 12.3% improvement over the control. The microstructural analysis provide qualitative support for the strength improvement observed at 6 wt% TiO₂. XGBoost achieved the highest predictive accuracy, with testing R 2 values of 0.96 for dye removal and 0.92 for compressive strength. LCA identified cement production as the primary environmental hotspot, while TiO₂ mainly contributed to acidification and particulate matter formation. Findings demonstrate the potential of TiO₂-modified cement mortar as a sustainable multifunctional construction material.