Bond-slip response of deformed bars in rubberised concrete

•Assessment of complete bond-slip behaviour of deformed bars in rubberised concrete.•Fifty-four pull-out tests on cylindrical specimens using two reinforcement sizes.•Direct evaluation of confinement effect and its influence on failure modes.•Examination of key bond parameters and detailed interfacial behaviour.•Proposed representations for bond characteristics and associated failure modes.

This paper is concerned with examining the complete bond-slip behaviour between deformed reinforcement bars and concrete incorporating rubber particles from recycled tyres as a partial replacement for mineral aggregates. An experimental study consisting of fifty-four pull-out tests on cylindrical rubberised and normal concrete specimens, in conjunction with two reinforcement sizes with short embedment lengths, is described. In addition to a detailed assessment of the full bond-slip relationship, the test results offer a direct interpretation of bond behaviour under practical levels of confinement and its influence on the failure modes. Particular emphasis is given to the characteristic bond behaviour of rubberised concrete in terms of maximum bond strength and splitting strength as well bond stiffness and slip parameters. The detailed test measurements and observations provided in this study enable the definition of key bond parameters depicting the interfacial behaviour between rubberised concrete and deformed bars. The findings also permit the development of modified approaches for reliable representation of the failure modes and bond capacities for the concrete materials considered in this investigation.