Corrosion

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Precast Texas-Style

The PCI show proves everything's bigger in precast. More

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Eliminating Corrosion

I recently read some papers on the corrosion of concrete in sewer manholes. Apparently, this is not a problem of gasses floating around in the sewer, but an issue of anaerobic bacteria (Thiobacillus) living on the surface of the concrete, creating sulfuric acid, which corrodes the concrete. The prevailing response has been to specify liners. However, there is an antimicrobial agent that does not allow Thiobacillus to live on (or in) the concrete. By eliminating the bacteria, you can eliminate the acid and the corrosion. The other issue is the high sulfate content of sewage. This could be addressed by following Portland Cement Association’s “Design and Control of Concrete Mixtures” requirements for concrete exposed to sulfate-containing solutions, (i.e. low water cement ratio, use of a pozzolan, higher compressive strengths, low alkali cements). By designing for a “moderate” sulfate environment and using an antibacterial agent as an admixture, you could eliminate the need for a liner. What other issues should be addressed in this type of application? More

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Corrosion Inhibition

Invention disrupts a harmful environment using an electrical current. More

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How Does Contact with Aluminum Affect Concrete?

Does anyone have information on the reaction between aluminum and concrete? More

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