锈蚀钢筋混凝土粘结强度试验

通过对配筋混凝土试块的实验室快速锈蚀,研究了锈蚀钢筋混凝土粘结强度的变化规律,并采用ICT技术观测了混凝土锈蚀裂缝。研究表明,混凝土保护层锈蚀裂缝沿钢筋径向的发展具有明确的方向性,且随着锈蚀率的增大,锈蚀试块呈现显著的脆性劈裂破坏特征,粘结强度与极限滑移量的衰减受锈蚀量、混凝土保护层厚度以及混凝土抗拉强度等影响,建立了以锈蚀产物厚度、混凝土相对保护层厚度与抗拉强度为独立参数的锈蚀钢筋混凝土粘结强度经验公式,与国内外实验结果的对比验证了模型的合理性。

Deterioration of reinforced-concrete bond strength due to corrosion

The environment-induced corrosion of steel bars in concrete results in deterioration of reinforcement-concrete bond properties, and causes the damage of concrete structures. The accelerated corrosion of reinforced concrete specimens and also the pull-out test of the corroded specimens were carried out to study the deterioration of corroded reinforced-concrete bond strength. We used industrial computed tomography (ICT) scanning to exam the cracking of the concrete cover of the specimens caused by corrosion. According to the pullout tests, the ultimate shear capacity and the corresponding displacement of the corroded specimens are degraded with the corrosion extent, and the bond stiffness is depressed. The analysis based on the experimental results shows that the thickness of corrosion products, other than the corrosion ration of steel bars, influences the corroded expansion force and the degradation of bond strength more directly. By introducing the factors of the thickness of corrosion, the ratio of thickness of concrete coat to the steel bar''s diameter, and the tension strength of concrete, a bond strength model of corrosion reinforced-concrete is proposed. The practicability of the suggested model is proved by experimental data.