Permeability of bonding interface between new steel fiber reinforced concrete and existing concrete

The impermeability of bonding interface between new steel fiber reinforced concrete and existing concrete of 90 composite cylindrical specimens is studied expeimentally.The new concrete of bonding specimens is reinforced with steel fiber of different volume fraction,such as 0,0.5%,1.0%,1.5% and 2.0%.The influences of steel fiber volume fraction,interface agent and surface roughness on the permeability are investigated and the characteristics and mechanical parameters of bonding interface between new steel fiber reinforced concrete and existing concrete are studied.The results show that the interface agent and the steel fiber can improve the impermeability of bonding interface,the impermeability of bonding inteface is continually increased with the increment of steel fiber volume fraction,the increment ratio of impermeability reaches 27% when the steel fiber volume fraction is 1.5% in new concrete.Based on experimental results,the calculating formula of permeability on bonding interface between new steel fiber reinforced concrete and existing concrete is put forward.