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Sulfates in solution in contact with concrete can cause chemical changes to the cement, which can cause significant microstructural effects leading to the weakening of the cement binder (chemical sulfate attack). Sulfate solutions can also cause damage to porous cementitious materials through crystallization and recrystallization (salt attack). [7]
The hydrogen sulfide gas is biochemically oxidized in the presence of moisture to form sulfuric acid. The effect of sulfuric acid on concrete and steel surfaces exposed to severe wastewater environments can be devastating. [1] In the USA alone, corrosion causes sewer asset losses estimated at $14 billion per year. [2]
Oxide jacking has caused concrete spalling on walls of the Herbst Pavilion at Fort Mason Center in San Francisco. The expansive force of rusting, which may be called oxide jacking or rust burst, is a phenomenon that can cause damage to structures made of stone, masonry, concrete or ceramics, and reinforced with metal components.
When it reacts with concrete, it causes the slab to expand, lifting, distorting and cracking as well as exerting a pressure onto the surrounding walls which can cause movements significantly weakening the structure. Some infill materials frequently encountered in building fondations and causing sulfate attack are the following: [2] Red Ash
Bhattacharyya [5] did a study on the three separate types of fungi that are known to cause concrete corrosion: Aspergillus tamarii, Aspergillus niger, and Fusarium. Aspergillus tamarii was the most destructive of the three fungi. It causes cracks to widen and deepen, quickly and efficiently takes root, and promotes calcium oxalate.
Examples may include sulfate-reducing bacteria (or sulfur-reducing bacteria), which produce sulfide and often cause corrosion of ferrous metals (and other alloys). Sulfide-oxidizing bacteria (e.g., Acidithiobacillus ), on the other hand, can produce sulfuric acid, and can be involved in corrosion of concrete.
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Similarly, corrosion of concrete-covered steel and iron can cause the concrete to spall, creating severe structural problems. It is one of the most common failure modes of reinforced concrete bridges. Measuring instruments based on the half-cell potential can detect the potential corrosion spots before total failure of the concrete structure is ...