Application of cathodic protection for controlling macrocell corrosion in chloride contaminated RC structures

2013 ◽  
Vol 45 ◽  
pp. 199-207 ◽  
Author(s):  
Moe M.S. Cheung ◽  
Chong Cao
2018 ◽  
Vol 7 (3.12) ◽  
pp. 333 ◽  
Author(s):  
Hirudayasamy Dolli ◽  
Andiappan Kavitha ◽  
Jeevarose .

This paper presents the results of performance of sacrificial protection in preventing the rebar corrosion in chloride contaminated and chloride free concrete. In this present study, the effectiveness of sacrificial protection of embedded steel rebars has been evaluated on chloride contaminated and chloride free concrete slabs using ribbon type Zinc anodes with ion conductive polymer backfill over a period of 250 days of exposure. The results showed that the ribbon type zinc sacrificial anodes with the navel electrochemical interface (Ion conductive polymer backfill) can confer effective corrosion protection of embedded steel in concrete on preventing corrosion initiation in chloride contaminated as well as chloride free concretes slabs. The cathodic protection criteria evaluated on concrete unit slab showed that 100-150mV is necessary in the atmospheric exposure and 160-200mV under alternate wetting & drying conditions. 


2018 ◽  
Vol 199 ◽  
pp. 04005 ◽  
Author(s):  
Xianglin Gu ◽  
Zheng Dong ◽  
Zhihao Jin

Steel reinforcement corrosion is found to be more severe at stirrups or some intersection zones of steel rebar mesh in concrete structures subjected to chloride penetration. This can be caused by macrocell corrosion formed between steel rebars with different potentials. Such potential differences are usually contributed by 1) chloride concentration gradients during the penetration process and 2) material differences between crossed steel rebars. With the forming of macrocell corrosion, the anodic current of steel with more negative potential will increase. The present study aims to deal with the macrocell corrosion between crossed steel macro-couples by dividing the steel rebar into intersected zone (IZ) and non-intersected zone (NIZ). The distribution of macrocell current on the surfaces of NIZ was obtained by means of a transmission line model. Based on the calculated macrocell current, the influence of the macrocell corrosion on the service life of reinforced concrete (RC) structures was analyzed. The results showed that the coupled micro- and macro-cell corrosion of stirrups could accelerate the change of the failure mode of a beam from bending to shear failure when the macrocell corrosion rate was no less than the microcell corrosion rate.


2018 ◽  
Vol 51 (6) ◽  
Author(s):  
Hayder M. Oleiwi ◽  
Yu Wang ◽  
Michele Curioni ◽  
Xianyi Chen ◽  
Guowen Yao ◽  
...  

2016 ◽  
Vol 711 ◽  
pp. 68-75
Author(s):  
Choorackal A. Eldho ◽  
Ominda Nanayakkara ◽  
Jun Xia ◽  
Stephen W. Jones

Corrosion of reinforcement steel bars is a major threat to the durability of concrete structures exposed to chloride contaminated environment. Patch repairing is widely practiced in affected structures to avoid further damage due to corrosion. Macrocell formation within the patch repair is identified as one main reason for the failure of patch repairs. In the present study, a group of patch repairing materials is tested for their potential to form macrocell corrosion after repaired in a chloride contaminated environment. The influence of parameters such as level of chloride contamination, type of repair materials and the area of steel bar receiving repair are presented based on macrocell current measurements. The selected repair materials for study were cement based, GGBS based and polymer based in its composition. It is found that the severity of macrocell depends on the driving potential existing between the repair and substrate concrete. The quality of substrate concrete and repair material influences the macrocell formation. The surface area of the steel bar that receives the repair also affects the macrocell current. The study will be used for the evaluation of repair materials for macrocell corrosion formation potential before their field application in a chloride contaminated environment.


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