混凝土中钢筋加速锈蚀试验适用性研究

钢筋锈蚀导致其屈服强度降低、力学行为改变，影响钢筋与混凝土之间的粘结性能，钢筋锈蚀量影响钢筋混凝土的失效模式。为研究锈蚀钢筋混凝土结构的相关性能，需要在较短时间内得到所需的锈蚀构件。通过对4种不同工况下混凝土中钢筋电化学加速锈蚀方法进行对比试验，得到了锈蚀后钢筋表面形态特征，分析了模拟自然环境条件下钢筋锈蚀的适用性。试验表明：全浸泡外加电流加速锈蚀方法使钢筋纵向、径向表面形成均匀锈蚀，而自然环境锈蚀钢筋表面锈蚀相对不均匀，坑蚀更明显，两者差异显著；利用全浸泡外加电流加速锈蚀方法进行锈蚀钢筋与混凝土粘结-滑移本构关系和锈蚀钢筋混凝土构件承载能力等研究不合适；半浸泡和贴面外加电流加速锈蚀方法能较好模拟自然环境锈蚀；加速锈蚀试验方法的理论锈蚀质量高于试验锈蚀质量。图12表1参7

Applicability study on accelerated corrosion methods of steel bars in concrete structure

Corrosion of steel rebar results in reduction of steel yield strength, change of steel mechanical characteristics and the behavior of the bond between concrete and steel rebar. The amount of corrosion of steel rebar affects the failure mode of reinforced concrete. To study the characteristics of corroded reinforced concrete structures, it is necessary to obtain corroded specimens in a short period of time. In this paper, four electrochemical accelerated corrosion methods for steel rebars in concrete structures were designed and examined experimentally to study their applicability. The experimental results show that the soaking method evenly corroded both horizontal and vertical surfaces of steel rebars. However, under natural corrosion process, the corrosion of surfaces of steel rebars is relatively uneven and pit corrosion is more obvious. Due to theses differences, it is not suitable to study the bond-slip constitutive relationship between corroded steel bars and concrete or the load carrying capacity of corroded reinforced concrete components obtained using soaking method. Half-soaking method and surface coating method with external current can simulate the natural corrosion process better. The theoretical corrosion mass of accelerated corrosion experiment is usually higher than the experimental corrosion mass.7Refs.In Chinese.