氯盐环境下桥梁混凝土结构的腐蚀行为及破坏机理

为了解决氯盐导致钢筋混凝土结构耐久性破坏的问题，通过测试处于氯盐侵蚀环境中混凝土内部Cl-含量、pH值及含碱量的分布规律，探讨了氯盐对混凝土结构的腐蚀行为和破坏机理；揭示了氯盐侵蚀下钢筋混凝土曲线桥梁过早劣化的机理，并对此类病害的防治及治理提出了合理建议。结果表明：干湿循环条件下，大量Cl-侵入混凝土内部并且到达钢筋表面，造成钢筋锈蚀、混凝土胀裂，且随Cl-含量增加，混凝土PH值下降，含碱量增大；在含有Cl-的区域，混凝土PH值均降低；氯盐入侵后，增大了混凝土碱骨料破坏的可能性，混凝土内部孔结构发生了明显粗化。

Corrosion Behavior and Destructive Mechanism of Bridge Concrete Structure Under Chloride Salt Environment

Aimed at the problem that chloride salt was the key factor that induced the destruction of reinforced concrete structural durability, the distributing rules of chloride ion content, pH values and alkali content were discussed by testing concrete samples got from chloride salt corrosion environment, and the corrosion behavior and destructive mechanism of concrete structure under chloride salt were studied. The deterioration mechanism of reinforced concrete curve bridge attacked by chloride salt was discussed and reasonable suggestions that how to protect and deal with such problems were proposed. Results show that under drying and wetting cycles condition, lots of chloride ions invade concrete and get to reinforce surface, which cause steel rusted and concrete cracked. With chloride ions contents increasing in concrete, pH values decreased but alkali content increased. With chloride ions coming into concrete, pH values in concrete is on the decline, so in the process of concrete corroded by chloride salt, it is possible to take place concrete alkali-aggregate destructing reaction. The pore structure of corresponding concrete is coarsened distinctly.