Experiment Study On The Performance Of Corroded Reinforced Concrete Beams

Damage due to reinforcement corrosion affects the durability of RC structures greatly. Many researches indicate that the reduction of effective diameter of reinforcement bars, carbonation in concrete, the loss of bond between steel and concrete and the micro-cracking or spalling of concrete due to the expansion of the bars as a consequence of electrochemical processes are the principal aspects of the corrosion damage. With the consideration of these factors, many studies, such as residual capability of corroded RC structures, to predict the serviceability of corroded RC structures, have been intensive in the past two decades.Based on all of these study results, two kinds of experiments with RC simply supported beams are carried out in this paper: first, imposed corrosion damage to22 simply supported beams under long-term load; second, imposed corrosion damage and artificial bending cracks to 5 simply supported beams with lumped masses. The corrosion damages zone in these two kinds of experiments were limited in different special ranges. With the contrast of experiment results between damaged beams and the intact beams, ultimate bending moment, bending stiffness, cracking characters of corroded beams, localization of damage with curvature of mode sharps and damage index analysis with frequency changes are studied. The following items are included:(1) Residual bending capability of corroded RC beams is studied. In the experiment, corrosion damage in the tensile side and corrosion damage in the compressive side are imposed to the test beam separately. And two corroded beams, with different corrosion ratio, are exposed to corrosion damage in both sides. The damage regions of all test beams are symmetrical to the center section. Experiment results indicate that bending capabilities of test beams with different location of corrosion damage are quiet different. Firstly, residual bending capacity of beam with only one side of corrosion damage is studied. And then, a new calculation model which considered the influence of corrosion damage at any location is set up. By this model, the ultimate bending moments of the two test beams with both sides corrosion damage are calculated. The calculation results can meet well with the test results.(2) Long-term deflection of corroded RC beam is studied. With the growing of corrosion damage, the stiffness of corroded beam under long-term load will decreased greatly. In this paper, the deflections at center-span of 9 test beams are measured during the whole test period, from 30 days to 80 days which are decided by their...