氯离子侵蚀环境下钢筋混凝土材料本体强度退化规律研究

Study on the Strength Degradation Law of Reinforced Concrete Material Under Chloride Penetration

在钢筋混凝土中,钢筋表面的氧化膜在处于氯离子侵蚀环境下时极易破坏并导致钢筋锈蚀,由此引发钢筋混凝土膨胀开裂,使结构强度下降。目前已有相关研究针对钢筋混凝土锈蚀问题进行了探讨,但得出的结论并不统一,原因在于氯离子侵蚀对素混凝土和钢筋这2类主要组成成分的影响规律不明确。为解决该问题,分别针对素混凝土和钢筋开展了素混凝土氯盐浸泡试验和电化学加速钢筋锈蚀试验,并得出如下结论:氯离子侵蚀使素混凝土抗压强度和锈蚀钢筋屈服强度小幅降低,这表明钢筋混凝土的破坏主要是由于并锈胀开裂而非材料本身的强度腐蚀。同时,分析了钢筋锈蚀的变异系数,并建立了锈蚀钢筋屈服强度计算模型。

In reinforced concrete,the oxide film on the surface of steel bars is extremely easy to be damaged and cause corrosion of steel bars under chloride penetration,which makes expansion and cracking of reinforced concrete and the decline of structural strength.At present,the corrosion problem of reinforced concrete have been discussed in relevant studies,but the conclusions are not unified because the influence law of chloride penetration on the two main components of plain concrete and reinforcement is not clear.The chloride salt immersion test of plain concrete and the electrochemical acceleration corrosion test of steel bars were carried out respectively for plain concrete and steel bars.The following conclusions were drawn that the compressive strength of plain concrete and the yield strength of corroded steel bars were slightly reduced by chloride penetration,which showed that the damage of rein-forced concrete was mainly caused by rust expansion cracking rather than not the strength corrosion of the material itself.At the same time,the variation coefficient of steel corrosion was analyzed and the calculation model of yield strength of corroded steel was established.