纤维增强复材筋增强工程用水泥基复合材料-混凝土复合梁受弯性能试验研究

EXPERIMENTAL RESEARCH ON THE FLEXURAL BEHAVIOR OF ECC-CONCRETE COMPOSITE BEAM REINFORCED WITH FRP BARS

为解决纤维增强复材(FRP)筋混凝土梁裂缝宽度和变形均较大的问题,采用受拉性能优良的工程用水泥基复合材料(ECC)取代FRP筋周围受拉混凝土形成FRP筋ECC-混凝土复合梁。通过对2组FRP筋ECC-混凝土复合梁、1组钢筋ECC-混凝土复合梁(每组5种不同ECC替代高度)的受弯试验,分析试件的开裂、屈服、极限荷载以及各级荷载下试件的挠度、裂缝、纵筋应变、混凝土平均应变。研究表明:钢筋/FRP筋与混凝土/ECC有较好的协同变形能力,ECC与混凝土也有较好的黏结性能;复合梁截面的平均应变均符合平截面假定;复合梁在正常使用状态下,受拉区ECC能充分发挥其应变硬化特性,形成较多细而密的裂缝;FRP筋ECC-混凝土复合梁可有效控制梁的变形值,提高梁的抗弯承载能力。

In order to solve the problem of the larger crack width and deformation of concrete beam reinforced with Fiber Reinforced Polymer（FRP） bars,Engineered Cementitious Composite（ECC） was used to replace the concrete around the FRP bars in the tensile zone because of its excellent tensile behavior.The flexural tests for two groups of ECC-concrete composite beams reinforced with FRP bars and one group of ECC-concrete composite beams reinforced with steel bars（each group has five ECC alternative height） were conducted.The cracking loads,yield loads and ultimate loads of specimens were analyzed,as well as the deflection,crack width,strain of longitudinal bars,and average strain of concrete.Experimental results showed that steel/FRP bars and concrete/ECC had excellent bonding behavior,ECC and concrete also had good bonding behavior; the average strain of cross-section could meet the plane assumption; the strain hardening characteristics of ECC was utilized in the serviceability limit state,and many small and dense cracks formed.The deflection of ECC-concrete composite beam reinforced with FRP bars could be effectively controlled and the flexural bearing capacities of beams were improved.