Protection of the surface of concrete structural elements is essential to safeguard from damages caused by environmental factors. For example, corrosion of reinforcement because of water/moisture permeability, chemical impact on structural components, and buildings near the coast cause damage to concrete structures. It is essential to protect the exposed surfaces of concrete structures to avoid such damage.
How to Protect a Concrete Surface
Most compounds have no impact on concrete. However, certain materials, including most acids, can damage it. The first line of defence against this type of chemical-based damage is to utilize high-quality concrete with the highest possible chemical resistance. Then undergo some protective measures that prevent corrosive chemicals from coming into contact with the concrete. Let’s discuss the preventive steps that can be used to avoid damage.
Protective Coatings for Concrete Surfaces
The following are some surface protection methods that can be used to prevent or reduce damages to concrete structures: hydrophobization, impregnation, sealants, and coating.
The level of concrete surface protection provided by these methods increases in the order in which they are mentioned above. The difference between the several types of surface protection is how the concrete surface is protected. The protection provided by the impregnation method is accomplished by preventing the concrete from absorbing water through capillary action. Depending on the surface protection material used, capillary water absorption can be prevented by hydrophobization of the gaps at the surfaces. Also, it can be done by restricting the capillary ducts created by film formation on these walls. Sealers and coatings create a closed thin layer on the surface of concrete, providing increased surface protection.
Impregnation and Hydrophobization Materials
Now that we have an overall idea about concrete materials and an idea about how to protect them, let us start with the materials you need.
Materials needed for hydrophobization and impregnation are silicon-organic solutions, oils, and resins.
Silicon Impregnation Materials
Maybe you are thinking about what silicon-organic materials are? For example, silicones, siloxanes, silanes, and silicon resins are silicon-organic impregnation materials.
Oil is an organic and low-molecular compound used for impregnation purposes. One of the widely used oils for this method is linseed oil. Linseed oil can be used in various ways, including mixtures of boiled linseed oil, linseed stand oil, and unsaturated organic compounds.
Resins protect the concrete surface by forming a thin cover over the tiny holes and pores. It also narrows the capillaries. Epoxy resins and polymethyl methacrylate (PMMA) are two types of resin materials used for this method.
Sealers are more effective than impregnation and hydrophobization methods. They work similarly to resins and also forms a thin layer over the concrete surface. The sealing of the concrete surface can be achieved by increasing the quantity of the impregnation agent, which can form a coating, or you can use suitable resins.
You can use epoxy resins (EP), unsaturated polyester resins (UP), polymethyl methacrylate (PMMA) resins, and polyurethane resins (PU) for this method. You can also use sealers as a primer for the coatings.
Coatings provide extra protection to the concrete surface. They also have increased resistance to the diffusion of internal moistures than resins. There are two types of coatings: thick and thin. The thin coating acts as a contour for an inconsistent concrete surface. On the other hand, the thick coating is used to create a plain surface with a thickness of 1mm or more. So, a thick coating can give you a smoother surface on an uneven surface like the concrete.
Characteristics of Superior Coating Materials
Suitable coating materials should possess the following properties:
- Resistant against temperature changes and chemical attacks
- Good surface adhesion
- Sufficient elasticity, tensile strength, and abrasive resistance
- Coefficient of thermal expansion equivalent to that of concrete
- Crack bridging capability
Surface Protection Material Use Methods
First, the concrete surface is prepared for the surface protection materials to start the impregnation process properly. The preparation is based on the depth of required impregnation. Then you apply the impregnation liquid to the surface. The amount of liquid should adequately fill the voids on the concrete surface. Next, use a brush, lambskin roller, or just a simple sprayer to apply it to the surface. You might need to repeat the spraying process depending on the absorptive capacity of the concrete surface.
You need thin solvent-based impregnation solutions to obtain a deeper penetration on the concrete surface during the first application. The penetration depth of a surface protection material is essential when the concrete surface is expected to wear. As a result, impregnation protection systems are only appropriate when the concrete surface will not be removed or damaged due to a crack. While resin impregnation can be utilized effectively on horizontal surfaces, hydrophobizing impregnations are not recommended for wet horizontal surfaces. As a result, it (hydrophobizing impregnation) is often used on vertical or sloping surfaces where water may quickly drain.
After all the processes are complete, you can use the sealers. As mentioned earlier, sealers are a better method than impregnation and also can be used as a primer. In addition, you can use sealers to coat the gaps and holes of the concrete surface and make it totally waterproof and then paint it. The sealer will not absorb the paint, which will make the color more vivid.
Now you have an overall understanding of the surface protection, including what materials to use and how to use them on a concrete surface. Use these methods to protect your concrete surface properly.