冻融循环和氯盐侵蚀作用下钢筋与混凝土的粘结性能

为了研究冻融循环和氯盐侵蚀两种因素对钢筋与混凝土粘结性能的影响，本文设计了光圆钢筋和螺纹钢筋两种钢筋混凝土试件，对其在三种不同冻融次数（15次、25次、50次）和三种不同浓度（3.5%、7%、10%）氯盐溶液条件下进行试验，探讨钢筋混凝土试件试验后的粘结性能退化规律。结果表明：光圆钢筋试件表现为拔出破坏，螺纹钢筋试件表现为劈裂破坏，当冻融循环次数较少时，钢筋与混凝土之间的粘结性能随着氯盐侵蚀程度的增加略有提高，当冻融循环次数大于等于25次时，粘结性能随氯盐浓度的增加而变差，冻融破坏程度不同，钢筋与混凝土粘结性能随氯盐浓度大小变化的敏感程度不同。最后根据试验结果拟合出冻融氯盐侵蚀后试件的粘结强度—滑移本构关系。

Study on Bond Behavior between Steel Bar and Concrete under Freezing-thawing Cycles and Chloride Erosion

In order to study the effect of freezing-thawing cycles and chloride erosion on the bond performance of steel bar and concrete, two kinds of reinforced concrete specimens, the steel bar in which were plain steel bar and deformed steel bar, were designed in this article, and the test was carried out under three different freezing-thawing times (15 times, 25 times, 50 times) and three different salt concentrations (3.5%, 7%, 10%), to explore the law of bond performance degradation of the reinforced concrete specimens after freezing-thawing cycles and chloride erosion. The results show that the specimens of plain steel bars exhibit pulling out failure ,and the specimens of deformed steel bars exhibit splitting failure. When the number of freezing-thawing cycles is less, the bond performance between steel bar and concrete increases slightly with the increase of chloride erosion degree. When the number of freezing-thawing cycles exceeds 25 times, the bond performance deteriorates with the increase of chloride concentration. The sensitivity of the bond performance between steel bar and concrete to the change of chloride salt concentration is related to the degree of freezing-thawing damage. Finally, the bond strength-slip constitutive relation of the specimens after the freezing-thawing cycles and chloride erosion are fitted by the experiment results.