A study on the effect of curing temperature and duration on rebar corrosion

摘要

The aim of this investigation was to study the corrosion activity in reinforced concrete exposed to different curing temperatures and durations using a wet-dry cycle corrosion test. Reinforced concrete samples were also tested under an impressed current accelerated corrosion test for comparison. In total, ten curing techniques were conducted by varying curing temperature (hot, normal and cold) and curing duration (1, 3, 7 and 28 d). These curing techniques were evaluated based on the results of wet-dry cycle, accelerated corrosion, rapid chloride permeability and chloride diffusion tests. The chloride threshold, pH value, current measurement, half-cell, mass loss and crack width readings were assessed during wet-dry cycle and impressed current corrosion tests. Heat-cured samples showed the highest chloride diffusion/permeability, shortest corrosion periods, and had the lowest chloride threshold and pH values. This was followed by cold-cured samples (28 d at 3-5 degrees C) and then air-cured samples (28 d at 23 degrees C). Curing samples in water for 28 d at 23 degrees C proved to be the best curing technique. Results also showed that the impressed current accelerated corrosion test can be used effectively to evaluate and compare corrosion activities in different qualities of concrete, but cannot be used after initiation of the first crack.