混凝土结构中钢筋锈蚀物体积膨胀率研究

Research on volumetric expansion ratio of corrosion products in concrete structure

采用通电加速锈蚀法对氯盐环境下钢筋混凝土结构保护层锈胀开裂时钢筋铁锈的体积膨胀率进行了研究．结果表明：采用低电流密度进行通电锈蚀时，钢筋铁锈的主要成分为Fe2 O3，Fe3 O4和 FeO （O H ），与自然锈蚀情况相似；通过推导分析得到了铁锈体积膨胀率的理论计算公式及其变化范围，表明铁锈的体积膨胀率仅与其所含各锈蚀产物的密度、膨胀率和质量分数有关．利用所建立公式对本研究及不同学者的试验数据进一步分析表明：混凝土中钢筋锈蚀后，生成铁锈的体积膨胀率在2．26～3．00之间；保护层锈胀开裂前后，钢筋铁锈的体积膨胀率对锈蚀方式不敏感，不同加速锈蚀法对混凝土试件内钢筋铁锈的体积膨胀率的影响不显著．

Study on volumetric expansion ratio of corrosion products at the stage of corrosive cracking of concrete cover was conducted with the method of electrifying accelerated corrosion under chloride environment .The results show that the main components of steel rusts are Fe2 O3 ,Fe3 O4 and FeO （OH） in low electric corrosion current density ,which is similar to the results in the natural corrosion condition .A theoretical formula and its variation range for calculating volumetric expansion ratio of corrosion products were obtained through derivation and analysis .The formula shows that the volu‐metric expansion ratio of rusts is only related to the density ,the expansion ratio and the quality per‐centage of the single corrosion product .A further analysis of the test data in this paper and in the pa‐pers of different scholars was conducted according to the established formula .The analysis indicates that the volumetric expansion ratio of corrosion products is between 2 .26 and 3 .00 after the corrosion of reinforcement in concrete structure .The volumetric expansion ratio of rusts in reinforced concrete specimens is not sensitive to the corrosion methods before and after the corrosive cracking of concrete cover and it is insensitive to different electrified accelerated corrosion methods .