Preliminary Study of the Effect of Revibration on Concrete-Steel Bond Strength

Abstract

The effects of revibration on concrete-steel bond strength are studied. Key variables are concrete slump, bleed, bar position, and the time interval between initial vibration and revibration. lt8 deformed reinforcing bars were used with a 2 in. cover and a 10 in. bonded length. Concrete slumps ranged from 2-3/4 in. to 7-1/2 in. Two specimen depths were used. All specimens were modified cantilever beam specimens. The experimental results show that revibration is not universally beneficial to concrete steel bond. Revibration appears to improve bond strength for top-cast bars placed in high slump concrete. Revibration may, however, severely damage bond strength for bars cast in well consolidated, low slump concrete. Revibration is almost universally detrimental to the bond strength of bottom-cast bars. Overall, revibration tends to reduce the differences in bond strength caused by differences in slump and bar position.