Impact of TiO2 powder type on hydration and photocatalytic NOx degradation in cement paste

• Effect of TiO 2 powder type on the hydration and mechanical properties of cement is investigated. • De-pollution characteristics of cement mortar were evaluated based on NOx degradation. • TiO 2 powder in cement was found to accelerate the initial hydration reactions. • TiO 2 powder enhanced the early strength of the cement through a filler effect. • De-pollution characteristics were significantly influenced by the anatase-to-rutile ratio. This study was aimed at developing novel functional construction materials with NOx removal capabilities using TiO 2 powder. To this end, the effects of the chemical composition of TiO 2 powder on the hydration process and the mechanical properties of cement were investigated. The hydration characteristics of the cement were assessed by analyzing the setting time and heat of hydration, while the mechanical properties were evaluated by measuring compressive strength at different curing ages. Additionally, the NOx degradation performance was examined. The results demonstrate that TiO 2 powder accelerates the hydration of cement, enhancing the compressive strength during the early stages of hydration. Furthermore, the NOx degradation performance of mortar specimens was enhanced with the incorporation of TiO 2 powder. However, the extent of these improvements varied significantly depending on the chemical composition of the TiO 2 powder, with the composition ratio of anatase and rutile being particularly influential. When utilizing TiO 2 powder to enhance the performance of construction materials or impart new functional properties, it is advisable to consider the composition of the TiO 2 powder to ensure alignment with the intended performance improvement objectives.