Experimental study on shear behavior of the interface between old and new deck slabs

An experimental study of the interface shear transfer between differently aged concrete (old and new deck slabs) has been performed. The old and new deck slabs parts were crossed by steel bars and subjected to the external prestressing force. The tests were carried out to be representative of a proposed technique used for widening prestressed concrete (PC) highway decks. The experimental program comprised nine specimens tested under double-shear test by taking the initial prestressing levels, connection methods between steel bars, reinforcement ratio and surface roughness as parameters. The experimental results indicated that the failure behavior of the interface was greatly affected by the initial prestressing level, reinforcement ratio and surface roughness of the interface. Finally, a comparison of the experimental shear strength with those given by JSCE Standard Specification, AASHTO and fib Model Code 2010 showed a conservative result for low and high prestressing levels, low reinforcement ratio and smooth surface.