Effects of reinforcement configuration and sustained load on the behaviour of reinforced concrete beams affected by reinforcing steel corrosion

摘要

Corrosion of reinforcing steel bars in concrete is one of the main causes of early deterioration and reduction of service life of reinforced concrete (RC) structures. This paper reports on the results of an experimental programme that was carried out to study the effect of reinforcement corrosion on the serviceability behaviour of RC beams under load. The main parameters investigated were the effects of reinforcement arrangement and the magnitude of the sustained load. Four series of scaled beams were tested, each series containing six beams, three of which were subjected to reinforcement corrosion while the other three were used as un-corroded control beams. All these beams carried the same sustained load during the process of reinforcement corrosion. The reinforcement arrangement for the fourth test series was identical to the first series but these beams carried a higher sustained test load. All the beams were subjected to a four-point bending load arrangement. Corrosion of the tension reinforcement was accelerated using an impressed current while the soffits of the beams were immersed in a 3% sodium chloride solution. The evolution of reinforcement corrosion and central deflection under simultaneous load and corrosion is given. The deflections of the beams increase with progressive corrosion of the reinforcement especially during the early stages of corrosion as a result of propagation of transverse cracks and the expansive stresses induced by the corrosion products. The importance of the arrangement of the steel in the section of concrete on the performance in terms of deflection was also clarified.