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为加速研究厌氧污水中生物膜对混凝土腐蚀的影响,人工配制了化学需氧量(COD)值高达7 000 mg/L的强化污水,并采用激光共聚焦扫描显微镜、压汞仪、热重分析等手段对污水腐蚀后的生物膜及混凝土的结构与性能进行了测试。结果表明:厌氧污水环境下混凝土试件的表面会变得粗糙、酥化,但并无十分明显的砂浆脱落,在腐蚀150 d后,有和没有生物膜附着的试件质量损失率分别为1.23%和1.67%,其抗压与抗折强度也相比同条件清水环境下有所下降,特别是表面被人工去除生物膜的试件。通过微观研究发现,污水腐蚀后的水泥石试样并无新的结晶相生成,但水化产物的数量和形貌均发生了变化,其中腐蚀150 d后有生物膜附着的试样中氢氧化钙含量和孔隙率分别为4.13%和31.82%,均优于没有生物膜附着的试样。这说明生物膜的存在影响了污水中腐蚀介质的传输,降低了其与水化产物之间发生的化学反应,起到了一定程度的保护作用。
In order to speed up the study on the influence of biofilm on the corrosion of concrete in anaerobic wastewater, artificial sewage was prepared with chemical oxygen demand (COD) of up to 7 000 mg / L. Confocal laser scanning microscopy, mercury porosimetry, Analysis and other means to test the structure and performance of biofilm and concrete after the sewage corrosion. The results showed that the surface of the concrete specimen in the anaerobic sewage environment would become rough and crisp, but there was no obvious mortar shedding. After 150 days of erosion, the mass loss rates of the specimens with and without biofilm adhesion were 1.23% and 1.67%, respectively. The compressive strength and flexural strength are also lower than those under the same clear water conditions, especially those with biofilm surface removed by hand. Through the microscopic study, it was found that there was no new crystalline phase in the samples of cement stone after the corrosion of wastewater, but the quantity and morphology of the hydration products changed. After 150 days of corrosion, Calcium content and porosity were 4.13% and 31.82% respectively, better than those without biofilm attachment. This shows that the existence of biofilms affect the transmission of corrosive media in sewage and reduce the chemical reaction with hydration products, which play a certain degree of protection.