반응성 분체 콘크리트(RPC) 부재의 직사각형 응력블록 계수

Abstract

In this paper, an experimental investigation of six steel fiber reinforced reactive powder concrete(RPC) columns was carried out deriving the appropriate design parameters of flexural induced columns with very high strength of concrete. Tested specimens have 200 mm square cross sections. Two of four specimens have rebars with 400MPa yield strength and another two specimens have no rebars. The RPC mix contains 2% of 0.2mm diameter by 13mm long straight steel fibres with concrete strength ranging from 100 to 200 MPa. Columns were induced to the flexural load by specially designed moment arm located at the end of columns with 10,000kN UTM. From the experimental data on the axial load, moment and strains along the longitudinal direction of columns, we could aware of the stress block of RPC with ultra high strength of concrete would be had a lower value than we use before. Test values represented that rectangular stress block parameter of ultra-shigh strength concrete was comparatively lower than values from the code provisions for concrete structure. For the more reliable calculating for stress block parameters of ultra-high strength concrete, existing test data of stress block parameter were investigated and regression analysis was carried out proposing new equation of rectangular stress block parameter α₁ and β₁.