Experimental study on mechanics behaviors of reinforced concrete beams under simultaneous chloride attacks and sustained load

In order to hold up the joint effect of chloride attack and loads on the actual reinforced concrete structures, a loading device to be subjected to sustained load was designed and made to be used for the experiment of large-size reinforced concrete beams. Accelerated corrosion experimental way was conducted on reinforced concrete beams by the electro osmosis-constant current-wet and dry cycle (ECWD) under the joint action of chloride attack and sustained loading. The load-deflection curve, ductility and other flexural properties of the specimens were studied by loading test. By use of rapid chloride test (RCT) method, distribution of chloride ion concentration within the concrete protection layer of test beams was measured. The corrosion degree of longitudinal reinforced bars in tensional region was evaluated by the way of half-cell potential measurements and steel weighing method. The experimental results showed that with the increase of sustained load level, the chloride ion concentration within the concrete protection layer was higher, and the chloride ion might be accumulated around longitudinal bars in tensional region. Furthermore, the corrosion degree and its uneven extent of longitudinal bars were greater. Also the flexural properties of the specimens, which included yielding load, ultimate load, displacement ductility, were to some degree degenerated while the curvature ductility factor was bigger. Moreover the greater the loading level was, the higher the degradation level was.