不同钢纤维含量对超高性能混凝土弯曲性能的影响

Influence of Different Steel Fiber Content on Flexural Properties of Ultra-high Performance Concrete

为了研究钢纤维含量对超高性能混凝土(Ultra-High Performance Concrete,简称UHPC)性能的影响,进行了立方体抗压、轴心抗压、弹性模量和四点弯曲试验研究。试验结果表明:随着钢纤维含量的增加,UHPC抗压强度增大,弹性模量略有提高,试件具有良好的受压变形性能。随着钢纤维体积含量的增加,UHPC的弯开裂荷载、极限荷载显著提高。当钢纤维体积含量从1.5%增加到3.0%时,开裂荷载提高了24.62%,极限荷载提高了31.83%。通过选取荷载-位移曲线上几个特征点,定量分析了钢纤维含量对UHPC弯拉性能的影响,发现考虑尺寸效应修正后的弯拉开裂强度均高于7 MPa,大弯拉变形状态下弯拉强度为开裂强度的1.24~1.52倍,增加钢纤维体积含量,有利于增强UHPC的弯拉性能。

To study the influence of steel fiber content on the performance of Ultra-High Performance Concrete(UHPC),the cubic compression,axial compression,elastic modulus and four-point bending test were carried out.The test results show that with the increase of the steel fiber content,the UHPC compressive strength increases,and the elastic modulus increases slightly,and the specimen has good compressive deformation performance.With the increase of the volume content of steel fiber,the bending cracking load and ultimate load of UHPC increased significantly.When the volume content of steel fiber increased from 1.5%to 3.0%,the cracking load increased by 24.62%and the ultimate load increased by 31.83%.By selecting several characteristic points on the load-displacement curve,the influence of steel fiber content on UHPC bending tensile properties is quantitatively analyzed.It is found that the bending tensile strength is higher than 7 MPa after considering the size effect,and the bending tensile strength is 1.24~1.52 times of the cracking strength under the condition of large bending tensile deformation.Increasing the volume content of steel fiber is beneficial to enhance the bending tensile properties of UHPC.