BOND BEHAVIOUR OF RCA CONCRETE

Abstract

Bond strength of deformed steel bar embedded in RCA concrete containing RCA replacement levels in the range of 0-100% has been experimentally investigated using splice beam specimens for the splice length of 15 and 25 rebar diameter. The mechanical properties of RCA concrete mixtures were seen to be influenced by the RCA source and the parameter brittleness index was used to characterise the relative magnitude of concrete compressive and tensile strength. The brittleness index of the RCA concrete containing RCA of unknown sources was observed to increase with increase in replacement ratio whereas that of the RCA concrete containing RCA obtained from known source was relatively unaffected by the replacement ratio. Splitting bond failure were observed with the splice lengths and the normalised bond strength was observed to decrease with increase in replacement for the RCA concrete containing RCA from unknown source which mirrors the trends observed for the brittleness index for this concrete. In the RCA concrete containing RCA from known source, like the brittleness index the bond strength was relatively insensitive to the aggregate replacement ratio. Based on the limited data base, the bond strength of 12 mm diameter deformed bars embedded in RCA concrete has been suggested to be equal to 75% of the value for natural aggregate concrete.