Studies on Chloride Induced Corrosion of Reinforcement Steel in Cracked Concrete

摘要

The durability of reinforced concrete (RC) exposed to severe environments depends largely on its ability to resist the penetration of aggressive compounds. This paper deals with the corrosion of reinforcement bars (rebars) in cracked concrete exposed to chlorides. A simple U-shaped specimen was used in the study, with a high yield strength deformed bar of 12 mm diameter placed at with 20 mm clear cover. Concrete specimens with three water to cement ratios (w/c) and pre-cracks exposed to chlorides were studied for quality assessment and quantifying the corrosion damage in terms of gravimetric weight loss. Water absorption and rapid chloride permeability tests indicated that as the w/c decreases, the water absorption and the charge passed were decreased. Accelerated corrosion test results indicate that flexural cracks cause macrocell corrosion of rebars in reinforced concrete. Concrete with higher w/c suffers higher rebar weight loss, even under cracked conditions. It appears that the corrosion induced crack width decreases as the pre-crack width increases and increases as the w/c decreases. The simple U-shaped specimen is found to be useful for the comparative evaluation of corrosion in different concretes under cracked conditions.