再生骨料混凝土梁受剪性能试验研究

通过对混凝土强度等级为C30、再生骨料替代率为0%、50%、70%配置的9根HRB500钢筋混凝土梁的试验,研究不同再生骨料替代率、不同剪跨比下,混凝土梁的破坏形式以及裂缝最终形态、宽度、变形、钢筋应变及受剪承载力等性能。试验表明:当剪跨比λ=1.5时,再生混凝土梁的破坏过程、形态和裂缝发展破坏形态与普通混凝土梁相同;当剪跨比λ=2.5,3.0时,破坏过程与裂缝发展相似,但破坏形态趋向塑性破坏,再生骨料混凝土梁斜截面受剪能力没有降低,且再生骨料替代率的大小对梁斜截面承载力影响不大;现行规范中斜截面受剪承载力的理论公式对再生混凝土梁是适用的,安全储备较高。建议再生混凝土梁设计剪跨比在2.5左右。

EXPERIMENTAL STUDY ON THE SHEAR BEHAVIOR OF RECYCLED AGGREGATE CONCRETE BEAMS

By experiment with the reinforced concrete beams of concrete strength grade of C30,recycled aggregate replacement ratios of 0%,50% and 70%,and having 9 HRB500 bars,different recycled aggregate replacement ratios,different shear span ratios,the failure mode,the final shape and width of the cracks,deformation,the steel strain,shear capacity and other properties were studied.Experiments show that when the shear span ratio λ = 1.5,the failure process and crack development failure mode of the recycled concrete beam is the same with the ordinary concrete beam,and when the shear span ratio λ = 2.5,3.0,the failure process and development of cracks is similar,and the failure mode tends to ductile failure.The bearing capacity of shear load within the inclined section of the recycled aggregate concrete beam is not reduced,and the recycled aggregate replacement ratios have little effect on it.The theoretical formula of the bearing capacity of shear load within the inclined section for the ordinary concrete beam is also applied to the recycled concrete beam.It is advised that the design shear span ratio of the recycled concrete beam is around 2.5.