| Currently, with concrete durability problems becoming increasingly outstanding,the premature breakage of concrete buildings-induced by inadequate durability isextremely serious which brings huge economic losses to our society. The applicationof protective coating is an effective measure to improve the durability of concrete.Water-borne protective coatings are eco-friendly and consequently it will become thedevelopment direction of concrete protective coating in the future.This thesis takes water-borne fluorocarbon coating as the main research object. Awater protection coating system composed of water-borne silicone acrylic emulsionprimer and water-borne fluorocarbon topcoat is selected first, then the coating systemprocess parameters such as coating thickness, viscosity and painting times areoptimized through testing the bibulous rate of concrete and the resistance of concreteto chloride ion penetration, ultimately, the optical coating system is achieved bypainting primer and topcoat twice respectively, and the best coating thickness isbetween280μ m and350μ m.The experiments based on lab simulation of sunlight aging, circulation variabletemperature and acid rain environment investigate the protection performance of theprotective coating system under different conditions. The primer surface is corrodedslightly after50times of acid rain erosion simulation. And with circulation variabletemperature simulation processing20times, the water-borne fluorocarbon topcoatappears blistering. This optical water protection coating system in this paperdemonstrate good protection performance in the sunlight aging environment, acid rainerosion environment and circulation variable temperature environment simulationtests. The penetrability of coating in the concrete surface and function mechanism isstudied through testing the surface tension and capillarity of coating. The results showthat the permeability of water-borne silicone acrylic emulsion primer is better thanother contrast samples.Finally, the repainting process and performance of damaged coating is researchedIt includes the influence of coating damaged degrees on the performance of theconcrete protective properties and the recoat coating protective performance indifferent environment. When coating damaged degree is over30%, the residuecoating has lost the concrete protective performance which needs to be repaired withthe coating. And when coating damaged degree is below20%, the residue coating stillhas certain some protective function and thus the repair time can be delayed. If thecoating is in a tough environment or the concrete is required to have a higherdurability, it is also should be repaired immediately though the coating damageddegree is20%. It is feasible to repair damaged coating in local region if the coating damaged in the effective period. The optical water protection coating system andwater-borne fluorocarbon topcoat demonstrate good recoat protection. |
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