Surface Treatment for Corroding Concrete Sewers
Publication Name
Engineering Materials
Abstract
To mitigate the corrosion on existing corroding sewers, various approaches of surface treatment have been developed including surface coating or lining, chemical spraying, and surface washing. These approaches target at isolating concrete from corrosive environments, inhibiting or removing the corrosion-inducing microorganisms, or increasing the corrosion resistance of the surfaces. Different coating/lining materials have been applied in corroding sewers, including polymer-based and cement-based materials. Polymer-based materials isolate the concrete from the corrosive environment, while cement-based materials generally have higher corrosion resistance, slowing down the corrosion development on concrete surfaces. For the same type of coating material, the corrosion mitigation performance varies in different studies. The chemical spraying majorly uses alkaline solutions or slurry such as magnesium hydroxide liquid and sodium. These solutions increase the surface pH of concrete, inhibiting re-establishment and activity of corrosion-inducing microorganisms. Although chemical spraying exhibit promising results in corrosion control, a frequent re-spay is required due to the wash-off of chemicals. Surface washing aims to remove the corrosion layer, which is the major habitat of corrosion-inducing microorganisms. However, in ordinary Portland cement-based concrete, the effect of surface washing on corrosion control is often temporal.
Open Access Status
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First Page
249
Last Page
261