الفهرس 
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Abstract
Reinforcing steel corrosion is considered one of the major causes of reinforced concrete deterioration. Chloride ions are considered between the most important causes of corrosion. Different techniques are used to extract chloride ions from concrete. Electro-chemical Chloride Extraction (ECE) technique is considered the most efficient technique recommended in the previous studies. The basic principle of ECE is to apply an electric field for a short duration between the steel bar and the externally deposited anode surrounded by alkaline electrolyte solution to remove the negatively charged chloride ions present around the steel surface. These ions migrate towards the external anode layer and thereby reduce the chances for corrosion initiation.
This basic principle for ECE is exactly the same like Impressed Current Catholic Protection (ICCP) except that the value of the applied external voltage used for ECE is higher than that of ICCP. The ECE decreases the chloride ions in concrete and increases the Ph value (due to the re-alkalization process) which reduces the danger of corrosion to a large extent. The major disadvantages of ECE technique are the increase of concrete permeability, decrease of concrete compressive and bond strengths and a decrease in the reinforcing steel ductility.
The main objective of this research work is to Study the effect of the following important variables on the efficiency of ECE:
- Spacing between reinforcing bars (those act as a cathode).
- Cathode type (internal cathode and external cathode were considered).
- Distance between anode and cathode.
- Number of reinforcing steel meshes inside the concrete.
- Location measured from the anode
Seven RC slabs were used in the experimental program to investigate the effect of these variables on the efficiency of ECE. Of course, there are other important variables affect the efficiency of ECE (like current intensity, duration of ECE, type of anode, concrete strength, …etc), these parameters were kept constant during the experimental investigation. Research results indicate higher efficiency of ECE by using internal cathode rather than external cathode, smaller distance between external anode and cathode, smaller distance measured from the anode.