Electrochemical chloride extraction: influence of testing conditions and mathematical modelling

To continue the work developed by the authors, in the field of application of electrical fields to concrete, electrochemical chloride extraction experimental trials were carried out in order to verify the assumptions made on the processes and its mathematical modelling. Studied variables have been: duration of the test (from 1 to 8 weeks of treatment), arrangement of the electrodes, type of regime (potentiostatic or galvanostatic) and the influence of renewing the external anodic solution (anolyte). From the results obtained, the efficiency of the technique regarding the percentage of extraction and chloride transport numbers has been calculated. This work has enabled the authors to demonstrate the reasons why the efficiency decreases with time and in consequence why the diffusion coefficient diminishes as the treatment proceeds, as well as to give the equations that model the extraction processes, allowing the duration of the treatment to be calculated.