基于梁式试验的CFRP布-混凝土界面剥离承载力计算模型研究

Study on Calculation Model of Interfacial Debonding Bearing Capacity of the CFRP-concrete Interface Based on Beam Tests

采用梁式试验方法,考虑混凝土强度、碳纤维增强复合材料(CFRP)布与混凝土表面宽度比、外贴CFRP布与混凝土表面长度比以及混凝土表面处理方式四个因素影响,对八个梁式试件进行了单调荷载作用下CFRP布-混凝土界面粘结性能的试验研究。试验结果显示,混凝土强度较低时,即使混凝土表面不做刻痕处理,CFRP布与混凝土界面也发生混凝土内部剥离破坏;高强混凝土表面需做刻痕处理,界面才发生混凝土内部剥离破坏。基于试验结果,分析了混凝土强度、CFRP布与混凝土表面宽度比以及外贴CFRP布与混凝土表面长度比对剥离承载力的影响规律,提出了考虑该三因素的CFRP布-混凝土界面剥离承载力计算模型,并拟合得出模型系数表达式,适用于计算CFRP布-高强混凝土界面剥离承载力。

Beam tests were applied to study bonding performance between carbon-fiber-reinforced polymer （CFRP） sheets and concrete. Monotonic loading tests on 8 beam specimens were carried out considering the factors including concrete strength, the width ratio of CFRP sheets to concrete surface, the length ratio of externally bonded CFRP sheets to concrete surface and the treatment of concrete surface. The test results showed that when concrete strength was low, although the concrete surface was not notched, debonding occurred in the concrete near the CFRP sheets-concrete interface, while debonding occurred in the concrete near interface when the notch treatment was done on the high-strength concrete surface. Based on test results, the influence law of concrete strength, the width ratio of CFRP sheets to concrete surface and the length ratio of externally bonded CFRP sheets to concrete surface on the debonding bearing capacity were analyzed. In addition, the calculation model of deboning bearing capacity of the CFRP-concrete interface was proposed, and the calculation formulas of model coefficients were derived by fitting test results. This model applies to the calculation of debonding failure load of the interface between CFRP sheets and high strength concrete.