Study On Properties Of Hybrid Fiber Self-compacting Concrete

Concrete engineering often encounters interlaced,complex and dense components,which leads to increased difficulty in pouring,and the requirements for pouring will also increase.In addition,the quality of traditional concrete pouring quality is affected by many factors such as artificial technology and working environment,and each factor may cause the concrete to be insufficiently dense.The self-compacting concrete has good working performance and no need to vibrate,which is not available in traditional concrete.It can still ensure the quality of concrete in places with dense reinforcement and difficult to pour and vibrate,so a more in-depth study of self-compacting concrete crucial.Checking the data shows that the fiber can significantly improve the strength of the self-compacting concrete,control the development of cracks,and also strengthen and toughen.Therefore,in this paper,polyester fibers of different lengths and different amounts and steel fibers with a volume fraction of 0.5% are mixed into self-compacting concrete to study and analyze the relevant laws of its working performance,some mechanical properties and crack resistance;The advantages and disadvantages of the two materials,pebble and crushed stone,as coarse aggregates are analyzed.The main work is as follows:(1)According to the requirements of self-compacting concrete specifications and the experience and research results of other scholars,in order to obtain a fiber self-compacting concrete mixture with working performance that meets the requirements,a T500 test and slump expansion degree were carried out on the newly mixed fiber self-compacting concrete Test,L-groove test,U-box test and J-ring test.The influence of fiber content,fiber length,single fiber,mixed fiber and different coarse aggregates(pebble and crushed stone)on the working performance of freshly mixed self-compacting concrete was analyzed and studied.(2)Part of the mechanical properties of the fiber self-compacting concrete cube test blocks with different mix ratios were tested,and the cube compressive strength and axial compressive strength of the mixed fiber self-compacting concrete with different volume and different lengths were measured or calculated.,Comparative analysis of the strength difference of cubic test block with coarse aggregate as pebble and coarse aggregate as crushed stone.(3)Ten mixed ratios numbered a and b were cast into reinforced concrete rectangular section beams and the beams were tested for crack resistance.The experimental study analyzed the crack resistance of hybrid fiber self-compacting concrete rectangular section beams and compared The difference between hybrid fiber self-compacting concrete beams made of two coarse aggregates(pebble and crushed stone)was analyzed.A large amount of research and analysis have been focused on the failure form,crack development in mid-span,crack number development,load-span deflection,and load-tensile reinforcement strain of hybrid fiber self-compacting concrete beams,and the span The crack width and mid-span deflection were calculated and analyzed and related conclusions were obtained.