Influence of cracks on chloride penetration and corrosion initiation time

Chloride initiated reinforcement corrosion is the main durability problem for concrete structures in a marine environment. If the chlorides reach the reinforcement steel, it will depassivate and start to corrode in presence of air and water. Since the corrosion products have a larger volume than the intial products, concrete stresses are induced, leading to spalling and degradation of the concrete structures. If cracks, caused by early drying, thermal effects, shrinkage or overstress, are present in the concrete, the penetration of chlorides is much faster compared to uncracked concrete. In this way, the corrosion process is initiated earlier. In order to study the influence of existing cracks in concrete structures on the penetration of chlorides a test program was set up at the Magnel Laboratory for Concrete Research of Ghent University, Belgium in cooperation with the "Politehnica" University of Timisoara, Romania. Cracks were made in cocnrete specimens with the Brazilian splitting test. The chloride penetration into the concrete was realised with a non-steady state migration test. Based on these experimental results, a crack influencing factor was determined. With this factor, the resulting time of corrosion initiation of the cracked concrete construction is determined and compared with the original time of corrosion initiation