高跨比和剪跨长度对UHPC弯拉性能的试验研究

Experimental Study on the Influence of Depth-Span Ratio and Shear Span Length on UHPC Flexural Tensile Performance

为研究超高性能混凝土(UHPC)的弯拉性能,以高跨比和剪跨长度为变量,进行了多组四点弯曲试验,探究高跨比和剪跨长度对UHPC弯拉性能的影响。结果表明:当其他设计参数不变时,UHPC试件跨中截面等效弯曲应力强度随高跨比或者剪跨长度的增大而减小;且各试件在纯弯区开裂时,达到极限荷载时位移量比较接近;剪跨长度越小,荷载-挠度曲线离散型越大;剪切变形对试件跨中纯弯段曲率影响较大。

To study the flexural tensile performance of ultra-high performance concrete(UHPC),multiple sets of four-point bending tests were conducted using depth-span ratio and shear span length as variables,and the influence of different depth-span ratio and shear span length on UHPC flexural tensile performance was evaluated.The depth-span ratio was set to 1/10,1/6 and 1/3,and the shear span length was respectively 100,75,60 mm,and each group contained 6 specimens.The results show that when the rest of the design parameters remain unchanged,the equivalent bending stress strength of the UHPC specimen in the middle span section decreases with the increase of depth-span ratio or shear span length.When the specimen cracks in the pure bending area,the ultimate load displacement is close.The smaller the shear span length,the larger the discrete type of the load-deflection curve.The shear deformation plays a greater impact on the curvature of the pure bending section.