Effect of microcracking and cracking on the development of corrosion in reinforced concrete members

摘要

The purpose of the work described here was to determine the effect of both cracking and microcracking on the service life of loaded reinforced concrete. This paper provides a synthesis of the results of experiments carried out over 12 years on reinforced concrete elements kept in a loaded state in a confined salt fog. The test specimens were beams 3 m long, which is a sufficient size to be representative of the actual operating conditions of reinforced concrete structures. The interpretation of the results allowed us to conclude that the development of reinforcement corrosion is not influenced by the widths of cracks (for widths less than 0.5 mm) or by the cracks themselves. It is, rather, the tensile microcracking in the concrete due to the service loading which increases the penetration of chloride ions and then reduces significantly the service life of the reinforced concrete. A relationship was estab- lished between the tensile stress in the rebar σs and the penetration of chloride; σs seems to be an important parameter of the durability of reinforced concrete.