Impact of TiO2 on the Physical and Mechanical Characteristics of Cement-Based Materials: A Review

Abstract

This paper reviews the effects of titanium dioxide (TiO₂) as a photocatalytic additive on the physical and mechanical properties of various types of concrete and cement mortars. It emphasizes changes in strength, durability, workability, and structural integrity under both standard conditions and adverse environments, including temperature variations, exposure to CO₂, gamma radiation, and electromagnetic waves. The findings indicate that TiO₂ in cementitious composites acts as a filler due to its fine particle size and promotes hydration. It aids in the formation of C-S-H gel through its catalytic effects, which help fill voids, increase density, improve both strength and durability, and reduce workability. Furthermore, it enhances electrical resistivity and bolsters resistance to acid and chloride attacks, while also increasing the material's capacity to absorb gamma rays and electromagnetic waves. The amount of TiO₂ used as a cement substitute should be kept to a minimum. The optimal range typically falls below 10%, specifically between 0.5% and 5%, because higher concentrations can reduce strength and durability. This paper offers valuable insights for civil engineers on the optimal proportions of TiO₂ and its effective use in conjunction with other additives. Moreover, researchers can use this study to explore potential future research directions.