Influence of nano-TiO₂ on the chloride diffusivity of concrete

In this research, the benefits of nano-titanium dioxide (nano-TiO₂) concrete over pure concrete in resisting the impacts of chloride diffusion were investigated. An increasing accelerative effect of chloride diffusion was experimentally discovered, which coincided with the movement in the exposed concrete surface caused by diffusion and the damage in concrete microstructure caused by chloride salt accumulation. The ‘time lag’ and ‘equivalent time’ between diffusion and migration tests were used to calculate the steady- and non-steady-state chloride diffusion coefficients. Concrete containing 2% nano-titanium dioxide by weight of cement demonstrated improved impermeability when compared with pure concrete, owing to improvements in microstructure and porosity. In comparison with pure concrete, the concrete containing nano-titanium dioxide had superior performance in resisting the effects of chloride diffusion. Because of its superfine particle size distribution and ‘filler’ effect, nano-titanium dioxide appeared to ensure decreased chloride diffusion in the investigated mixes. The test findings revealed that adding supplemental cementitious elements to mortar enhanced its resistance to chloride penetration.