Problems of Concrete Protection against Biogenic Sulfuric Acid Aggression by Means of Polymer Coatings

The work is devoted to the determination of the causes of destruction of organic polymer coatings designed to protect concrete structures in sewer collectors from microbiological sulfuric acid corrosion. The breakage of these coatings occurred as a result of intensive expansion of concrete under the coating, which indicated that mineral acid freely diffuses through the organic coating. To elucidate the causes of this phenomenon, a detailed analysis of the metabolites of the microbiocenosis that develops on the arch part of collectors was carried out. Among the organic substances identified were phospholipids, phthalic acid esters, alkanes, alcohols, and aromatic compounds. These organic compounds can attack the polymer coatings of concrete, making them permeable to sulfuric acid and therefore not effective in protecting concrete from biogenic sulfuric acid aggression. Therefore, it is necessary to test the effectiveness of polymer coatings not in model solutions of sulfuric acid, but with exposure of samples in an operating sewer collector.