Flexural experiment and stiffness investigation of reinforced concrete beam under chloride penetration and sustained loading

• We investigate the effect of corrosion and sustained load on structural behavior of reinforce concrete beam.
• The results indicate that load levels have a significant effect on the rise of steel corrosion level, and the decrease of flexural stiffness and degradation of flexural capacity.
• The formula of the ratios of the different position of steel bar corresponding with different sustained loading levels was given.
• The equation was deduced to calculate the flexural stiffness of corroded reinforced concrete.

This paper presents an experimental study conducted to characterize the effect of corrosion and sustained load on structural behavior of reinforced concrete (RC) beam. The effects of loading level on corrosion of reinforcing steel, the flexural deflection and residual loading capacity of the test beams were investigated. In the first scenario, two non-corroded beams were tested to determine the maximum load levels that were required by the beams to reach their deflection limits and that were also tested for the sustained levels of the applied loads. For the second experiment, the corrosion was accelerated through the application of external direct current whilst the beams were under the load equivalent to 0%, 50%, 65% and 80% of the ultimate load. The results indicate that load levels have a significant effect on the rise of steel corrosion level, the decrease of flexural stiffness and the degradation of flexural capacity. The mechanical properties like the strength and ductility are significantly impaired due to simultaneous effect of loading and corrosion in comparison to the effect of the single parameter at a time. Considering the corrosion situation of different position of steel bar, the formula of the ratios of the different position of steel bar corresponding with different sustained loading levels was given. An equation was deduced to calculate the flexural stiffness of corroded reinforced concrete and can be served as a reference for deflection calculation of corroded reinforced concrete beams.