Permeable concrete topcoat is a spraying process that completely seals the road surface after the maintenance of permeable concrete pavement is completed. In industry terminology, permeable concrete topcoat is referred to as double-component polyurethane sealing treatment protective agent, which requires

imported curing agent with a solid content exceeding 40%. In the cross-sectional design drawings of permeable concrete pavement, we often see the term: surface colorless transparent double-component polyurethane sealing, imported curing agent, solid content above 40%, as shown in the figure below! The selection of permeable concrete topcoat material directly affects the appearance and durability of permeable concrete. High-quality permeable concrete topcoat has strong curing efficiency and adhesion, fully sealing the surface of permeable concrete stone to form a robust, wear-resistant, and oxidation-resistant layer. The formed coating should not be scratched, protecting the durability of the permeable concrete color. Based on 17 years of experience in ecological engineering construction, design drawings often require communication and modification. Colorless transparent protective agents are insufficient to fully cover the concrete color because concrete itself contains cement, whose main component is lime. Lime reacts with water and air to oxidize and form alkali, a phenomenon known in the industry as efflorescence. Colorless transparent double-component polyurethane sealing treatment struggles to completely remove efflorescence from the permeable concrete surface. Therefore, a color agent matching the permeable concrete color should be added, and colored double-component polyurethane sealing treatment should be used to achieve the desired effect.

What kind of paint is permeable concrete topcoat? It is a specialized paint for permeable concrete.

First, it offers **brightening effects superior to traditional road surface protective agents.

It meets the mechanical performance, functional requirements, and service life of the structure.

Second, it has the property of protecting the permeable floor, achieving the effect of preventing surface particle shedding.

Fourth, it has excellent functional performance, significantly extending the floor's service life.

Fifth, it provides functions such as color retention, non-fading, and anti-carbonation.

It is suitable for surface sealing protection of permeable floors, colored pavements, concrete components, etc. It offers good yellowing resistance, weather resistance, and an elegant appearance. Permeable concrete protective agent, also known as permeable concrete surface coating, concrete cover agent, or permeable concrete sealer, comes in colors and transparency. Depending on the material, there are oil-based and water-based variants. Based on application methods, there are two-component and single-component types. As an outdoor permeable concrete protective agent, its weather resistance and UV performance are primary considerations. The permeable concrete protective agent itself is composed of resins and additives, and the performance varies significantly with different resins, especially in terms of resistance to direct sunlight. Poor resistance to direct sunlight can lead to surface brittleness, peeling, and color fading over time. Two-component permeable concrete protective agents generally refer to double-component polyurethane sealers, consisting of one part resin and another part curing agent. During use, they need to be weighed proportionally and mixed, making the application process relatively cumbersome. Bangwei Building Materials believes that this type of permeable concrete protective agent requires high-performance curing agents with strong resistance to direct sunlight and non-yellowing properties. Currently, most of these curing agents are imported from abroad, resulting in high costs. Several large domestic chemical enterprises also produce them, with costs similar to imported ones, but their performance is relatively inferior.