Effects of surface modification of silane coupling agent on the properties of concrete with freeze-thaw damage

Surface waterproofing treatment with silane coupling agent is developed to prepare surface modification concrete, in recent years, which possesses an excellent permeability resistance. Freeze-thaw damage inevitable exists in concrete exposed to the cold environment, therefor this paper intensively investigates the effects of surface modification of silane coupling agent on the properties of concrete with freeze-thaw damage. Freeze-thaw cycles, capillary absorption, chloride penetration and carbonization tests were carried out, respectively. The results demonstrate that the surface waterproofing treatment is appropriate for the durability repairing of concrete with freeze-thaw damage, and the penetration depth of silane coupling agent in concrete increases linearly with the rise of freeze-thaw damage. The water and chloride permeability both increase with the increased freeze-thaw cycles for various concrete; however, the surface modification concrete has a better permeability resistance than ordinary concrete with the same freeze-thaw damage. In particular, the permeability resistance increases with the increases of applied amount of silane coupling agent, and there exists a good correlation between the permeability behavior and induced freeze-thaw damage for various concrete. Abrasion significantly decrease the permeability resistance of surface modification concrete, which should be considered carefully in the durability repairing.