氯盐腐蚀对持荷钢绞线的性能退化的影响

摘要

为了研究氯盐环境对预应力混凝土中钢绞线耐久性的影响,进行了持荷钢绞线在不同浓度氯盐溶液环境中加速腐蚀试验.对腐蚀钢绞线试件的质量损失及静力拉伸性能进行研究,分析氯盐溶液浓度对腐蚀钢绞线腐蚀程度及性能退化特性的影响;并提出了钢绞线腐蚀速率计算公式.结果表明:氯盐腐蚀下钢绞线表面呈现片状和带状蚀坑分布,腐蚀钢绞线的屈服荷载和极限荷载分别降低了1.66%~2.51%和3.38%~5.09%,各组试件平均质量损失率为1.42%~3.24%,腐蚀速率为0.040~0.091 mm/a.试验腐蚀条件下钢绞线腐蚀程度与氯盐溶液浓度成正比;但各腐蚀钢绞线的名义弹性模量降低幅度不大.%In order to analyze the influence of durability of steel strands in prestressed concrete structures in chloride salt condition , the accelerated corrosion tests of loaded steel strands in chloride solution with different con-centrations were carried out .Then the mass loss and mechanical property from static tensile test were studied .The influence of concentrations of chloride solution on the corrosion degree and deterioration characteristic of corroded steel strands was analyzed .A formula of corrosion rate of steel strands was presented .The results show that corro-sion pits at steel strand surface present flake and zonal distribution under the chloride salt corrosion ,the yield load and ultimate load of corroded steel strand is reduced by 1.66%~2.51%and 3.38%~5.09%respectively , aver-age mass loss rate of each specimens is 1.42%~3.24%, and the corrosion rates are 0.040~0.091 mm/a.Un-der the condition of this experiment , the corrosion degree of steel strand is proportional to the chloride salt solution concentration , but the nominal elastic modulus of corroded steel strands decreases not by much .