层布式钢纤维再生混凝土梁的抗弯性能

Flexural behavior of layered steel fiber recycled aggregate concrete beams

为了研究层布式钢纤维再生混凝土(Layered Steel Fiber Recycled Aggregate Concrete,LSFRAC)梁的抗弯性能及承载力,以钢纤维层撒布量与纵筋配筋率为参数,对1组再生混凝土梁与5组LSFRAC梁实施4点弯曲静力加载测试。结果表明:LSFRAC梁的加载经历与再生混凝土梁相似,均经历了弹性、开裂、屈服、破坏4个阶段;随着钢纤维层撒布量的增加,开裂荷载先增加后保持不变,极限荷载与刚度逐渐增大,梁破坏时的挠度与纵筋应变逐渐减小;随着配筋率的增大,开裂荷载先增加后保持不变,极限荷载、刚度、梁破坏时的挠度与位移延性系数逐渐增大,纵筋应变逐渐减小。最后,通过修正《纤维混凝土结构技术规程》(CECS 38:2004)中的既有公式,得出LSFRAC梁抗弯承载力的计算公式。

In order to study the flexural behavior and bearing capacity of layered steel fiber recycled aggregate concrete beams,four-point bending static loading tests are carried out on a group of recycled aggregate concrete beam and five groups of layered steel fiber recycled aggregate concrete beams,taking the content of steel fiber and the reinforcement ratio as parameters.The results show that the loading experiences of layered steel fiber recycled aggregate concrete beams are similar to that of recycled aggregate concrete beam,and there are four characteristics:elasticity,cracking,yielding and failure.With the increase of steel fiber content,the cracking load increases first and then remains unchanged,the ultimate load and stiffness increase gradually,and the deflection and strain of longitudinal reinforcement decrease gradually.With the increase of reinforcement ratio,the cracking load increases first and then remains unchanged,the ultimate load,stiffness,deflection and displacement ductility coefficient increase gradually,while the longitudinal reinforcement strain decreases gradually.Finally,the formulas in CECS 38:2004 are revised to obtain the formulas for calculating the bearing capacity of layered steel fiber recycled aggregate concrete beams.