Durability Aspects of Concrete Containing Nano-Titanium Dioxide

The current paper investigates the effects of partial cement replace-ment with nano-titanium dioxide (nano-TiO2 [NT]) in varying weight proportions in concrete. In the C20/25 grade of concrete, NT was added by weight of cement with partial replacement of 0, 0.5, 1.5, 2.0, 2.5, and 3.0% using portland pozzolana cement. The physical and mechanical properties of the resulting concrete were assessed, as well as aspects of durability such as sorptivity and nondestructive tests (NDT) such as ultrasonic pulse velocity (UPV). Compared with the control mixture, the fresh concrete produced showed a drastic reduction in slump with increasing percentage of replacement, with a 54% reduction at a 3.0% replacement. Furthermore, for 1.5% NT, the compressive, flexural, and splitting tensile strengths peaked at 7, 28, 56, and 90 days, after which the values decreased. The addition of NT improved the homogeneity and integrity of the resulting concrete based on the UPV values. As the percentage of NT increased, chloride penetration decreased. From microstructural studies, it can be concluded that NT acts as a filler material and can be used as a partial replacement for cement in concrete up to 2% by weight.