Effect and mechanisms of surface treatment using nano titanium dioxide on the permeability of cementitious materials

Abstract

Corrosive media typically penetrate the interior of cementitious materials through porous structures, causing corrosive damage. Strengthening the surface structure of the substrate is an effective method for enhancing the durability performance of such a material. This study investigates the effects of different concentrations of a nano titanium dioxide suspension (NTS) used for the surface treatment of cement specimens after 24 h of molding and the influence of this treatment on the impermeability of the substrate surface. The results indicate that at 28 d of hydration, water absorption by the 1 % NTS-treated specimens decreases by 45 %, and the resistance to chloride-ion penetration increases by 32.7 % with respect to that of the control group. Furthermore, results of the microscopic tests indicate that when NTS surface treatment is conducted on hardened cementitious materials, NTS provides nucleation sites to enhance the degree of cement hydration, fill minuscule voids, promote the dispersed growth of hydration products, optimize the surface pore structure, and increase the density of the microstructure, thereby improving the impermeability of the substrate surface. This study is expected to provide innovative ideas for the future utilization of nanomaterials for strengthening surface structures and enhancing the durability performances of cementitious materials.