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微生物腐蚀是指由微生物或其代谢产物所引起的材料破坏和恶化。为了研究放射性环境土壤中优势微生物对水泥砂浆腐蚀的影响,以湖南铀尾矿场址土壤中富集培养筛选的优势细菌菌群作为砂浆试件的腐蚀质,采用浸泡腐蚀的方式,通过测试特定腐蚀龄期砂浆试件的质量损失、强度损失、碳化深度,并采用扫描电子显微镜和X射线衍射仪进行微观分析,来研究微生物对砂浆的腐蚀作用。结果表明:随腐蚀龄期增长,细菌试验组的试件抗压强度明显低于无菌对照组,腐蚀龄期为168 d时,细菌试验组的抗压耐腐蚀系数降到0.86,而无菌对照组在0.9以上;细菌试验组质量损失率和碳化深度均高于无菌对照组,腐蚀龄期为168 d时,细菌试验组碳化深度达2.0 mm,是无菌对照组的2倍;微观结构显示,有细菌存在的条件下更易生成钙矾石晶体,从而影响砂浆的力学性能及耐久性。研究表明,优势细菌的存在能加速水泥砂浆的腐蚀。
Microbial corrosion refers to the destruction or deterioration of materials caused by microorganisms or their metabolites. In order to study the influence of dominant microorganisms in the radioactive soil on the corrosion of cement mortar, the dominant bacterial flora enriched and screened in the soil of uranium tailing site in Hunan Province was used as the corrosive substance of the mortar specimens by immersion corrosion method, Corrosive age mortar specimens of the mass loss, strength loss, carbonation depth, and the use of scanning electron microscopy and X-ray diffraction microscopic analysis to study the role of microorganisms on the corrosion of mortar. The results showed that with the increase of corrosion age, the compressive strength of specimens in the bacterial test group was significantly lower than that in the sterile control group. When the corrosion age was 168 days, the compressive and corrosion resistance coefficient of the bacteria test group dropped to 0.86, The control group was above 0.9; the mass loss rate and depth of carbonization in the bacterial test group were higher than that in the sterile control group. When the corrosion period was 168 days, the depth of carbonization in the bacterial test group was 2.0 mm, which was twice that of the sterile control group; The structure shows that it is easier to form ettringite crystals in the presence of bacteria, thus affecting the mechanical properties and durability of the mortar. Studies have shown that the presence of dominant bacteria can accelerate the corrosion of cement mortar.