Study On The Fracture Performance Of Steel Fiber Reinforced Concrete With Silica Fume And Polymer Emulsion

As a new composite material,the development of steel fiber reinforced concr ete is very quickly and has certain application in the engineering field.For furth er expansion research the performance of steel fiber reinforced concrete,this pap er is purposed to improve the mechanical properties of steel fiber reinforced con crete by adding silica fume and polymer emulsion.So this research were carried by the performance of steel fber reinforced concrete at different content silica fu me and polymer emulsion,compressive strength and flexural strength,fracture perf ormance under different experimental conditions,the morphology and pore distrib utionof cement substrate surface.The main contents of this paper were as follows.(1)Tested the performance of the fresh steel fiber reinforced concrete at differ ent content silica fume and polymer emulsion.The slump,water retention and oth er indicators could be remain within a certain range through control the content of superplasticizer.The slump of steel fiber reinforced concrete was reduced whe n mixed with silica fume,and the slump of steel fiber reinforced concrete was i mproved when mixed with polymer emulsion.(2)The tests on the mechanical properties of concrete showed that compressive strength and flexural strength could be inproved when mixed with silica fume,a nd usually had a maximum value when the content of silica fume was 12%.Th e effect of polymer emulsion to steel fiber reinforced concrete was not as silica fume.(3)Through making steel fiber reinforced concrete notched beam specimens an d using these specimens conduct three-point bending test,the test results were pr ocessed to obtain fracture curves.By comparison the fracture curves,fracture tou ghness,fracture energy and crack tip opening displacement,steel fiber can effecti vely improve the fracture properties of ordinary concrete.The fracture toughness of steel fiber reinforced concrete would be increase with the increase of silica fu me,but the fracture energy and crack tip opening displacement showed certain d ecline trend and usually had a minimum value when the content of silica fume was 12%.The polymer emulsion could alleviate stress concentration,limit crack initiation point of split and expansion,thus improved the fracture energy and the crack tip opening displacement of steel fiber reinforced concrete,scilicet increase the ability to adapt to the deformation,but the fracture toughness showed certai n decline trend.(4)Through SEM test,the low temperature nitrogen adsorption experiments,th e water absorption and desity test,these test results showed that silica fume and polymer emulsion could ameliorate the microstructure of steel fiber reinforced co ncrete,increased the density of concrete,reduced the specific surface area and u nit pore volume,and obtained the effect of silica fume and polymer emulsion to the density and porosity of steel fiber reinforced concrete.