Enhancing the early–age waterproof properties of mortars by incorporating silane and alkyl silicate

Abstract

Water and corrosive ions can easily penetrate into the microstructure of cement–based materials and cause structural damage, given the intrinsic hydrophilic and porous properties of the materials. This paper aimed to enhance the early–age waterproof properties of mortars by incorporating silane and alkyl silicates. The hydration products, pore structure, and microstructure wettability of mortars and cement pastes were analyzed by conducting XRD, TGA, FT–IR, SEM, and MIP measurements. Test results showed that the addition of hydrophobic agents hindered the general hydration of cement and thus deteriorated the pore structure of the mortars. But the early–age waterproof properties of mortars significantly increased, given the enriched distributions of hydrophobic chemicals in the calcium silicate hydrate rich areas where connected pores are prone to exist. The addition of potassium methyl silicate with the emulsion of isobutyltriethoxysilane and sodium dodecyl sulfate (SDS) caused a stable flocculation structure of the SDS, which thus enhanced the dispersion stability of the isobutyltriethoxysilane and increased the hydrophobicity of mortars.