影响FRP筋与混凝土黏结性能的主要因素

目的阐述FRP筋混凝土的黏结机理。探讨影响FRP筋与混凝土黏结性能的主要因素．方法对84个FRP筋混凝土试件进行中心拉拔试验。总结和分析试验结果，对影响FRP筋与混凝土黏结性能的主要因素进行研究．结果剪切滞后使受拉FRP筋横截面中心与边缘的变形有一定差异，横截面的正应力非均匀分布，使得黏结强度随FRP筋直径的增大而降低．试件的黏结强度随埋深的增加而降低．对于混凝土强度等级大于C15的试件，混凝土强度对黏结强度的影响还难以定论．另外，FRP筋的表面形式和不同类型纤维组成也是影响其与混凝土黏结性能的重要因素．结论FRP筋直径、埋置深度、FRP筋表面形式和类型等均对FRP筋与混凝土之间的黏结性能有重要的影响，而混凝土强度的影响还难以确定，仍需要大量的试验进行验证．试验结果为深入了解FRP筋与混凝土的黏结性能提供了依据．

Study on Main Factors of Bond Strength between FRP Bars and Concrete

In all,84 pullout tests of concrete specimens reinforced with FRP bars and the results obtained are discussed in this paper.Based on the test results,the bond mechanism and relative influence factors of concrete reinforced with FRP bars were studied in detail.The experimental results showed that the bond strength decreased as FRP bar diameter increased.The same was the influence of embedment length.The reasons were that shear lag made the difference between the core of bar's cross-section and surface fibers,which led to the non-uniform distribution of normal stress.When the concrete strength was greater than 15?MPa,the influence of concrete strength to bond was not obvious,so large numbers of tests were demanded to verify it.In addition,surface characteristics and types of fibers adopted had different effects on the bond strength.The study may be contributed to understand the bond capability between the FRP bars and concrete.