Accelerated laboratory evaluation of surface treatments for protecting concrete bridge decks from salt scaling

In this accelerated laboratory study, several commercial products of surface treatment were included in the test program, including three concrete sealers, two crack sealants, and two water repellents. To characterize the product longevity under traffic, the abrasion resistance of concrete treated by each product was tested. To characterize the product effectiveness against salt scaling, the surface treated concrete cylinders were subjected to the joint action of 15 freeze/thaw and wet/dry cycles and exposure to a diluted deicer simulated by 3 wt.% NaCl solution. The mass loss of these concrete cylinders during the freeze/thaw cycles was periodically measured. For mechanistic investigation, the surface-treated concrete specimens were further tested for their water absorption rates, gas permeability, and water contact angle. For all the laboratory tests, the untreated concrete was used as control. The results confirmed the benefits of using these products to treat the surface of concrete against salt scaling, as all of them exhibited outstanding performance and reduced the mass loss of the concrete by 90% or more. Among them, two products (epoxy-based sealer T48CS and water repellent ATS-42) exhibited the best performance in protecting the concrete from salt scaling and featured the highest resistance to abrasion and generally lower water absorption rates and gas permeability coefficients. The results suggest that high resistance to both gas and water penetration is a crucial property in a good surface sealer, crack sealant or water repellent applied to concrete.