Effect of steel fiber types and content on mechanical properties of high performance concrete
In order to study the influence of the type and content of steel fiber on the mechanical properties of high performance concrete(HPC),20 groups of tests were designed and completed,including 9 groups of reactive powder concrete(RPC)and 11 groups of high strength fiber reinforced concrete(SFRC)containing coarse aggregate.Cube compression test,dumbbell tensile test and four point bending test were carried out respectively.The results show that the mechanical properties of RPC are significantly improved by the straight micro-filament steel fiber,but the improvement of mechanical properties of SFRC is not as great as that of coarse and long fiber.The compressive strength,tensile strength and flexural strength of RPC with 1.5%straight microfilament steel fiber and SFRC with 1.5%end hook steel fiber can be increased by 16.1%,123.4%,103.0%and 10.7%,59.1%,38.4%respectively.The compressive strength of SFRC reaches the maximum fiber content of 1%~1.5%,and other mechanical property indexes of the two high-performance concrete increase with the increase of fiber content.When the steel fiber content is 2%,the bending toughness of RPC and SFRC reaches 79.31 N/mm and 62.28 N/mm,with an increase of 1081.9%and 2195.4%respectively.When the steel fiber content exceeds 2%,the bending toughness of SFRC decreases gradu-ally with the increase of the fiber content.