The effect of mixing different types of steel fibers on the flexural performance of ultra-high performance concrete(UHPC)with metakaolin was studied by four point bending tests.The results show that an increase in the length of steel fibers will lead to a decrease in the slump extension and deterioration of the working performance of UHPC,and the length of mixed steel fibers should not exceed 20 mm;The stress corresponding to the inflection point of initial deformation and elastic deformation is around 7.5 MPa.In the initial deformation stage,the stress is mainly on the matrix,and after the elastic deformation stage,the stress is jointly on the matrix and steel fibers;The bending strength and peak deflection of UHPC gradually increase with the increase of steel fiber length,while the bending toughness energy first decreases and then increases with the increase of steel fiber length.When the fiber length to diameter ratio is 100,the bending performance of YD group is about 1.25 times that of BD group;The addition of metakaolin can improve the microstructure of concrete and provide more hydration attachments for steel fibers.On the macro level,it shows a significant improvement in flexural performance.
关键词
超高性能混凝土/钢纤维混掺/偏高岭土/抗弯性能/微观结构
Key words
ultra high performance concrete/steel fiber mixing/metakaolin soil/bending resistance/microstructure
维普
万方数据