Resistance of Cement-based Grouting Materials with Nano-SiO2 Emulsion to Chloride Ion Penetration

The chloride penetration resistance of cement-based grout materials was improved by nano-silica emulsion. Specimens of mixtures containing different nano-silica particles or emulsions were exposed in sodium chloride solutions of specific concentrations with different test ages. Hardened properties of the mixes were assessed in terms of weight loss and compressive strength. X-ray diffraction (XRD) and scanning electron microscopy (SEM) of mixes were performed to analysis the phase evolution and microstructure. The results demonstrated that the introduction of nano-SiO2 emulsion significantly decreased the compressive strength loss and calcium hydroxide (CH) crystal content of hydration production, and then enhanced the resistance of cement-based grouting materials to chloride ion penetration. This improvement derives from the filling and pozzolanic effects of nano-SiO2 particles, which were incorporated via an emulsion and attributed to a well dispersion in grouting matrix.