A Study on Corrosion Behavior of Carbon Steel in Artificial Solution of Geopolymer Paste by Open Circuit Potential

Abstract:

This paper presents an experimental study on corrosion of carbon steel as reinforcement bar in artificial solution of geopolymer paste by Open Circuit Potential (OCP). The OCP measurements have been used in reinforcement bar concrete studies for many years to determine the corrosion behavior of materials. OCP is the potential of the working electrode relative to the reference electrode when no current or potential is being applied to cell. The OCP of reinforcement bar was recorded with time and this experiment has been done for 30 days. A copper/copper sulfate (Cu/CuSO₄) reference electrode with a potential V-SHE of +0.318 V (at 25oC) was used in this study. The pH of geopolymer concrete was observed to be in the range of 11.5 to 12.5 depending on the formulations. Thus, in this study the artificial solutions of geopolymer paste that were used are pH 11, pH 12 and pH 13. It has been found that the potential values of three solutions were fluctuated from the beginning until day 30. The highest potential value was indicated by pH 13 whereas the maximum value is 0.542 V and minimum value is 0.205 V while pH 11 shows the lowest potential value with the maximum value 0.356 V and the minimum value-0.047 V. However, all the redox potential values for pH 11, pH 12 and pH 13 were located at passivity region, Fe₂O₃. The Fe₂O₃ is the stable phase in which this oxide acts as a protective film or passive layer in this region. It would be expected to provide some protection against corrosion. Keywords: corrosion, artificial solution, geopolymer paste, reinforcement bar, open circuit potential, passivity

• Periodical: Applied Mechanics and Materials (Volumes 754-755)
• Pages: 892-896
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.754-755.892
• Online since: April 2015
• Authors: Farah Farhana Zainal*, Kamarudin Hussin, Azmi Rahmat, Mohd Mustafa Al Bakri Abdullah, Andrei Victor Sandu
• Keywords: Artificial Solution, Corrosion, Geopolymer Paste, Open Circuit Potential, Passivity, Reinforcement Bar

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