Improvement of Freeze‐Thaw Resistance of Concrete by Polyvinyl Alcohol Membrane and Silane

Abstract

The surface protection can improve the waterproofness of concrete, thus reducing the saturation inside and improving the freeze‐thaw resistance (FT). Polyvinyl alcohol (PVA) membranes with different thicknesses and silane with varying impregnation depths are selected to improve the FT resistance of concrete as surface protection. The damage morphology, mass variation, ultrasonic pulse velocity, and mechanical characteristics of concrete after 125 FT times are analyzed according to the slow freezing method, and the damage mechanism is studied by scanning electron microscope in different depths of concrete. The results show that PVA membrane can improve the FT resistance of concrete and do better than silane because the silane can only keep dry inside the concrete but the surface still spalls off. And, the protection effect of PVA is a negative correlation with membrane thickness because the thicker the PVA membrane the better the air tightness and the membrane is easier damaged. On a microscopic level, the damage of PVA‐protected concrete is gradually weakened from the surface of concrete to inside, and there is an obvious boundary between the damaged and undamaged zone of silane‐protected concrete. This article provides a new idea for FT protection of concrete.