Interfacial bonding properties of styrene-butadiene rubber and ethylene vinyl acetate emulsion-modified OPC–CAC–G repair mortar

Abstract

Inorganic repair materials such as ordinary Portland cement–calcium aluminate cement–gypsum (OPC–CAC–G), which consist of ordinary Portland cement, aluminate cement, and gypsum, have advantages of fast hardening, high early strengths, and minimal expansion; however, they also have the disadvantages of low bond strengths and weak interface areas, which often lead to repair failure. The interfacial bonding properties of repair materials can be improved by adding highly flexible polymers. In this study, the effects of styrene-butadiene rubber (SBR) and ethylene vinyl acetate (EVA) on the interfacial bonding properties of OPC–CAC–G bonding and the mechanism of the effect of the microstructure are examined using X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results show that and EVA are both effective in improving the interfacial bond strength of OPC-CAC-G repair mortars. SBR is suitable for the modification of repair mortars with an optimum dose of 20%; EVA is suitable for the use as an interface agent on the surface of damaged concrete substrates with an optimum concentration of 40%.