No abstract

This work attempts to determine the best conditions for applying the Electrochemical Chloride Removal (ECR) in rebars embedded in cement mortar with chloride additions by monitoring the corrosion rates before, during and after the application of an ECR. The ECR was applied at different conditions of current density (1 and 2 A/m 2 of steel surface), application times (15, 30 and 60 days) and degree of precorrosion of the rebars. According to the results obtained, if ECR is applied preventively, it is an efficient procedure for delaying the start of corrosion. However, if applied too late, it does not assure the repassivation of corroded reinforced concrete structures and is therefore useless. The efficiency of the ECR depends heavily on the application time and the degree of precorrosion of the rebars.

Different materials, such as triturated waste tire (WT) particles, have been proposed as aggregate to improve mortar properties and reduce its cost in recent years. Using WT as aggregate implies material recycling, providing an environmental benefit. Previous studies show controversy on the chloride ion diffusion coefficient in mortar test specimens as a function of the WT content. The objective of this investigation is to evaluate the corrosion rate of steel reinforcement embedded in mortar specimens using WT as aggregate when exposed to chlorides. Electrochemical techniques, mercury intrusion porosimetry and scanning electron microscope were used to measure corrosion rate, porosity and microstructure of mortar matrix, respectively. Corrosion rate and porosimetry results were found to directly correlate for test pieces with 7.5% of WT compared with control samples and test pieces containing 5%, 10% of WT; such results are supported by visual inspection of steel reinforcements. Our results show that substituting 7.5% of sand with WT when preparing mortar provides the optimum protection.