Modelling of corrosion of reinforcement in contact with cracked concrete cover

摘要

Macrocells which form between active and passive areas on steel reinforcement bars in cracked concrete caused by external mechanical tensile stresses and the associated rate of corrosion are investigated. The investigations were carried out in potentially aggressive environments which modelled the concrete water pore solution of carbonated concrete beams containing chloride ions. The investigations confirm that in addition to being dependent on the agents that can initiate cprrosion of the reinforcing steel and the extent of the anode zone, the advancement of corrosion is largely determined by the size of the area within which the cathode processes take place. A comparison of the corrosion current densities in actual cracked reinforced concrete elements with those investigated in this paper demonstrates that for that reinforcing bars in typical environmental conditions, the anode area/cathode area ratio ranges from A_a/A_c=1:1 to A_a/A_c=1:2.