Failure Mechanisms of protective coatings for concrete

Regardless of the technology chosen, every protective coating will eventually come to the end of its life. Selecting the right technology gives a better opportunity to do this in a planned way. When selecting a technology to protect a concrete surface, it is critical to understand how and why they fail, and more importantly, the cost that will be incurred to repair or replace the coating. Mechanisms of failure can range from blistering, increased porosity, cracking and sheet collapse due to wall adhesion failure. Some cracking failures can exacerbate acid attack by allowing accumulation of acid inside the failure. While sheet collapse, there is a risk of water flow blockage in channels at the bottom of the asset which can result in high emergency repair costs. Some surface coatings can be very sensitive to surface water, humidity and dust on the surface during the application process, risking early life failure. Salt content that has penetrated a called white metal, has a strong negative effect on the adhesion of polymer coatings, but assists in the adhesion of some chemical barrier coatings such as PROTECTA-Mag™. Repair or replacement of a failed protective coating ranges from simply water washing through to an expensive confined space entry with hot work and manual handling to remove the coating. This can be particularly difficult when the coating has collapsed inwards and blocked the outlet of the asset. This whitepaper investigates the end of life decommissioning costs of the protective coatings available in the market to determine the whole of life cost of application of a type of coating.