宁夏地区临水钢筋混凝土结构腐蚀性病害的研究

Study on Corrosivity Reinforced Concrete Structure Adjacent to Water in Ningxia

为了了解宁夏地区服役的临水钢筋混凝土结构腐蚀性病害状况,选取了宁夏5市的部分临水钢筋混凝土构筑物进行调研,通过对地表水进行水质分析和对损伤混凝土进行XRD分析,揭示了宁夏临水钢筋混凝土结构的腐蚀性病害现状。结果表明:吴忠市是宁夏临水钢筋混凝土结构病害最严重的地区,水中硫酸根离子的质量浓度也是最高的;临水混凝土结构的病害主要是由硫酸盐结晶的物理侵蚀造成的,伴随有少量的化学侵蚀,同时叠加冻融循环作用。根据调研结果,将宁夏地区混凝土的腐蚀性病害从轻到重划分为混凝土表面盐结晶、坑蚀、保护层脱落及核心混凝土溃散4个病害等级。调研中现有的防腐措施依然存在着很大的不足,有待于从硫酸盐结晶、干湿循环和冻融循环共同作用下的抗腐蚀材料以及与旧基层的黏结性能方面进行研究。

In order to understand the corrosivity of reinforced concrete(RC)structures in service in Ningxia,some RC structures in five cities of Ningxia were selected for investigation.Through water quality analysis of surface water and XRD analysis of damaged concrete,the corrosivity of RC structures adjacent to water in Ningxia were revealed.The results show it is the worst in Wuzhong City with the highest mass concentration of sulfate ion in water.The deterioration of RC structures adjacent to water is mainly caused by the physical erosion of sulfate crystals,accompanied by a small amount of chemical erosion,and freeze-thaw cycles.According to the investigation results,the corrosivity of concrete in Ningxia are divided into four grades frommoderate to severe:salt crystallization on surface,pitting corrosion,protective layer falling off and core concrete collapsing.The present anti-corrosion measures are with great deficiencies,which need to be studied from the anti-corrosion materials under the combined action of sulfate crystallization,dry-wet cycle and freeze-thaw cycle and the bonding performance with the old base.