既有污水混凝土构筑物表层及内部混凝土腐蚀情况研究

Study on Corrosion of Surface and Internal Concrete of the Existing Sewage Concrete Structures

通过混凝土中性化深度测试并综合XRD、SEM、EDS、X-CT等微观测试手段对既有污水混凝土构筑物表层混凝土的腐蚀深度进行定量化表征。对污水混凝土构筑物内部混凝土力学性能、微观性能、内部钢筋锈蚀情况、氯离子含量分布进行测试,确认内部混凝土的腐蚀情况。通过污水水质分析推测污水混凝土构筑物腐蚀破坏的可能原因。结果表明,既有污水混凝土构筑物表面往下深度5 mm以内的混凝土受腐蚀较为严重,表面往下5~22 mm深度范围内的混凝土发生轻度的钙溶蚀,距腐蚀表面深度大于22 mm的内部混凝土未受腐蚀,污水构筑物表层混凝土受腐蚀的主要原因为有机物在微生物作用下形成的酸溶蚀。

The corrosion depth of surface concrete of existing sewage concrete structures was quantitatively characterized by means of concrete neutralization depth test and micro-test methods such as XRD, SEM, EDS and X-CT. The mechanical properties, microscopic properties, corrosion state of steel bars and chloride ion content distribution of concrete inside were tested to confirm the inside concrete corrosion. The possible causes of corrosion damage of sewage concrete structures are inferred through the analysis of sewage water quality. The results show that the concrete of existing sewage concrete structures with a depth of less than 5 mm below the surface is corroded seriously. The concrete with a depth of 5~22 mm below the surface undergoes slight calcium corrosion. The concrete with a depth greater than 22 mm away from the corroded surface is not corroded. The main reason for the corrosion of sewage concrete is the acid corrosion caused by organic matter under the action of microorganisms .