Effect of Protective Coatings on Frost Resistance of Concrete Structures in Northeast Coastal Areas

Dalian is located in the northeast coastal area, and the complex environment has caused severe freezing and thawing damage to the marine concrete. The experiment used polyurea, polyurethane, epoxy mortar to protect the concrete surface, and then carried out indoor rapid freeze-thaw test to analyze the effect of coating on the antifreeze performance of concrete. The concrete samples were subjected to mercury intrusion test before and after the freeze-thaw cycle to analyze the pore structure changes of the concrete before and after erosion. The test results show that the concrete covered by protective coating has a lower mass loss rate and a higher dynamic elastic modulus than the unprotected concrete, the order of anti-freezing performance of the protective coating from strong to weak is: epoxy mortar > polyurethane > polyurea. By isolating the concrete from the corrosive environment, the protective coating can delay the ingress of corrosive materials, slow the tendency of harmless pores in the concrete to multiple the harmful holes and harmful pores, improve the frost resistance of the concrete, and prolong the use of the concrete structure life. (paper)