Concrete is one of the most common substrates that CIM protects. CIM high performance coating and linings are often used to coat concrete due to its elastomeric abilities to bridge cracks and move with the concrete as it contracts and expands with temperature changes. CIM is chemically resistant and helps protects the concrete from erosion and can extend the life of the structure. To ensure that the CIM will properly protect and adhere to the concrete, special care should be given to the surface preparation.
Surface preparation is very important when applying any liquid applied coating. To ensure the industrial coating will adhere to the concrete, it must be clean, dry and have a profile. For newly poured concrete, it is important to let it cure to a minimum compressive strength of 3000 psi and have less than 5 percent moisture in the concrete. Though the surface may look dry, CIM requires less than 5 percent in the concrete for maximum adhesion. Many tests can be done to check the level of moisture, the most popular are the ASTM D4263 Plastic Sheet method, the Radio Frequency test and the Calcium Chloride Test. Testing the substrate for moisture prior to the application is imperative. An abundance of moisture in the substrate may result in poor adhesion and possibly lead to blisters and disbondment of the protective coating. It is also important to remove the cement paste and apply the CIM directly to exposed aggregate. Although CIM will adhere to the cement paste, the paste does not have much strength which therefore affects the adhesion. For both new and old concrete, it is important to ensure that the surface is free of bug holes. In existing concrete, cracks must be properly sealed and the concrete must be free of any contaminants before CIM is applied. To properly clean and prepare new or old concrete the preferred method is by abrasive blasting. CIM requires a surface profile, generally expressed as an ICRI 4 to 6, of expose aggregate to maximize the CIM adhesion. Once the surface of the concrete is properly prepared, CIM can be applied. CIM’s adhesion to properly prepared concrete is 350 psi, which is the tensile strength of concrete.
For additional information, please consult our published application guides.
C.I.M. Industries Team
www.cimindustries.com
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