Chloride transmission in silane composite emulsion-protected concrete under the coupling effect of flexural loading and wetting–drying cycles

The coupling effect of flexural loading and wetting–drying cycles on chloride transmission in silane composite emulsion-protected concrete is presented in this paper. Graphene oxide/isobutyltriethoxysilane (GS) and tetraethyl orthosilicate/isobutyltriethoxysilane (TS) composite emulsion was prepared to obstruct the penetration of chloride, and the influence of flexural loading and exposure time on the protective effect were mainly considered. The results show that the content and diffusion coefficient of chloride are affected significantly by flexural loading, exposure age, and protective emulsion. Loads with different stress ratios affect the internal transmission of chloride by changing the compactness of concrete. The prolongation of the exposure age leads to the accumulation of chloride, thereby increasing the internal chloride contents of concrete. The GS/TS composite emulsion reacts with the hydration products to form the hydrophobic layer, which can significantly prevent the penetration of chloride. In particular, the protective performance of GS under low stress ratios is better than that of TS, while under high stress levels, TS has better resistance to chloride erosion. Relatively speaking, the long-term protective effect of GS is better than that of TS.