钢筋超高性能纤维混凝土梁抗弯性能研究

通过8根采用自密实和常温标准养护制成的试验梁的静力加载试验,研究不同配筋率受弯构件的抗弯性能。试验结果表明:与相同基体强度和配筋率的钢筋混凝土梁相比,加入钢纤维后梁的极限承载力提高约13%,位移延性系数提高158%;加入钢纤维后梁的初裂荷载、裂缝宽度为0.1 mm时的荷载值占极限荷载的比例较对比梁大幅度提高,但裂缝宽度为0.2 mm时的荷载值与对比梁差别不大;随着钢筋配筋率的提高,试验梁极限承载力会相应的提高,相对于配筋率为0.86%的梁,配筋率分别为1.52%、2.38%时,梁的抗弯承载力分别提高72%、113%;参照CECS 38∶2004《纤维混凝土结构设计规程》,提出了钢筋超高性能纤维混凝土受弯构件正截面抗弯承载力计算方法,计算结果与试验结果吻合较好。

FLEXURAL BEHAVIOR EXPERIMENTS OF ULTRA-HIGH PERFORMANCE CONCRETE BEAMS REINFORCED WITH STEEL BAR AND HYBRID-FIBER

The beams were cast with self-compacting UHPFRC and cured in normal temperature.The flexural behaviors of 8 UHPFRC beams with different reinforcement ratio were tested by static loading.The results showed that the bearing capacities of ultra-high performance concrete beams reinforced with steel bars and hybrid-fiber were increased by 13%,the ductility factors were increased by 158%,as compared with beams with the same strength of the matrix and reinforcement ratio.Comparing with the beams without fiber,the initial crack load,and load of 0.1 mm crack width of beams with fiber when the load is accounted for the proportion of the ultimate load greatly improved,but the load of 0.2 mm crack width was not very different.Comparing with beams with reinforcement ratio of 0.86%,the flexural capacities of beams were increased by 72% and 113% respectively when the reinforcement ratios of beams were 1.52% and 2.38%.The calculating methods of the flexural capacities of UHPFRC beams reinforced with tensile steel bars and hybrid-fiber were proposed according to the document.The calculated results corresponded well with the experimental data.