Study On Mechanic Properties And Durability Of Hybrid Fiber Reinforced Self-compacting Concrete

Concrete is largest amount and most widely used civil engineering materials in the world.However, it has shortcomings of brittle, low tensile strength, easy to crack, need vibrators and others. Fiber reinforced self-compacting concrete has advantages combine fiber reinforced concrete with self-compacting concrete, which can effectively solve the problems, such as brittlene in service life of concrete.At present, the most researchers focus on single-doped fiber reinforced concrete, compared with singledoped fiber reinforced concrete, hybrid fiber reinforced concrete combine with different types and size of fibers, two different fibers give full play to enhance, toughening and crack resistance in the concrete. This thesis main research on work performance, mechanical properties, durability and the microscopic properties on self-compacting concrete with single-doped fiber and hybrid fiber. Mainly to complete the following work:(1) It carries on workability test on fiber reinforced self-compacting concrete, analysis impact of single-doped fiber and hybrid fiber(carbon fiber,cellulose fiber) on reinforced self-compacting concrete work performance. The results show that effect of carbon fiber on the working performance than cellulose fiber and single-doped fiber and hybrid fiber reinforced self-compacting concrete decreased performance.(2) It carries on mechanic performance test on fiber reinforced self-compacting concrete, analysis impact of single-doped fiber and hybrid fiber on cube compressive strength, splitting tensile, axis compressive and static elastic modulus of fiber reinforced self-compacting concrete. The results show that single-doped fiber and hybrid fiber were able to effectively change the brittle failure mode of concrete.(3) Research on hybrid fiber reinforced self-compacting concrete durability performance,the results show that single-doped fiber and hybrid fiber both can improve the durability of self-compacting concrete. Use fiber spacing theory and fiber composite theory to analysis single-doped fiber and hybrid fiber effect on early crack resistance, shrinkage properties and resistance to chloride ion penetration of fiber reinforced self-compacting concrete.(4) Conduct SEM and three-dimensional reconstruction experiments, analysis the effect of fiber on microscopic properties of self-compacting concrete. The results show that a single fiber can disperse evenly blended mix, improve microscopic pore structure of concrete, cement-based adhesive and tight.