Evaluating the effects titanium dioxide on resistance of cement mortar against combined chloride and sulfate attack

摘要

The objective of this study is to develop the durability of mortar mixtures against combined chloride and sulfate deterioration by replacing a certain amount of limestone cement with titanium dioxide (TiO2). Marine environments contain high concentrations of chlorides and sulfates. To improve the concrete durability within such conditions, it is important to control the concentration of both ions. The application of TiO2 in concrete has been increasingly considered in recent years. However, the durability issues of mortar made with TiO2 have not been evaluated. To achieve this purpose, an experimental program was designed to assess five different corrosive solutions of chloride and sulfate to investigate different partial cement replacement by TiO2. The compressive strength, surface electrical resistance, mass change, dynamic modulus of elasticity, Rapid chloride migration test (RCMT), Rapid chloride permeability test (RCPT), and half-cell energy were tested in the binary and ternary solutions. Results indicated that using these nanoparticles as a partial replacement of cement developed the pore structure of the mortar, leading to the improved durability of the mortar and less deterioration in control specimens. Also, the chloride penetration increased by adding sulfate content at early age immersion. With little to no TiO2 in the mortar specimens, chloride ions mitigated the corrosive influences of a sulfate attack.