Mechanism of concrete deterioration caused by micro organisms

某地下混凝土结构遭到严重破坏，原因据信是微生物产生的代谢物。在这项研究中，几种类型的细菌在结构周围的土壤中分离和培养在有氧条件下。然后进行了使用细菌的砂浆模拟试验，并分析了细菌产生的代谢产物的组成。结果，钙离子从浸泡在用细菌繁殖的培养基中的砂浆中溶出，并且发现有机酸和碳酸被细菌代谢。众所周知，混凝土会被厌氧细菌严重破坏，但这项研究表明，好氧细菌代谢的有机酸和碳酸也会导致混凝土腐烂。

A certain undergroud concrete structure had been severely damaged, and the cause was belived to have been metabolites prorduced by microorganisms. In this study, several types of bacteria in the soil around the structure were isolated and cultured under aerobic conditions. Mortar simulation tests using the bacteria were then carried out and the composition of the metabolites produced by the bacteria analyzed. As a result, calcium ion was dissolved out from mortar soaked in the culture medium bred with the bacteria, and it was found that organic acids and carbonic acid were metabolized by the bacteria. It is already known that concrete can be severely damaged by anaerobic bacteria, but this study suggests that organic acids and carbonic acid metabolized by aerobic bacteria can also cause concrete to deterirate.