Concrete Beams with Steel Reinforcement Subjected to Fractions of Yielding Strength Under Accelerated Corrosion Tests

The objective of this work was to verify that tensile stresses at 40% and 80% of the corresponding yielding strength are not structurally influenced by the level of corrosion under accelerated tests. One of the main concerns when having corrosion of reinforcing steel is the sustaining stress level before non-reversible corrosion damage. Eight reinforced concrete beams (15 cm x 30 cm x 350 cm) were designed by using local crushing aggregates with a water/cement ratio (w/c) of 0.62. Accelerated corrosion was applied to the tensioned longitudinal reinforcing steel bars by contaminating the concrete during the mixing process and later with wetting and drying cycles. A four-point bending load test setup was used to the posttensioned beams in pairs and simulating sustained loads. The loads were applied until reaching the tension stresses in the longitudinal reinforcing steel bars at 40% or 80% of the yielding strength of the bars. It was concluded that the average loss of the beam stiffness after flexural cracking was 76%. Few changes were observed in the corrosion potentials for those beams, then the tensile stresses at 40% and 80% of the yielding strength do not influence the corrosion potential level measured at the ages, materials and conditions tested.