Print Email Facebook Twitter Evaluation of Ag/AgCI sensors for in-situ monitoring of freee chloride concentration in reinforced concrete structures Title Evaluation of Ag/AgCI sensors for in-situ monitoring of freee chloride concentration in reinforced concrete structures Author Pargar, F. Koleva, D.A. Copuroglu, O. Koenders, E.A.B. van Breugel, K. Faculty Civil Engineering and Geosciences Department Structural Engineering Date 2014-02-19 Abstract The level of free chloride concentration in reinforced concrete structures essentially determines the onset of steel corrosion initiation and further propagation. One of the well-known methods for monitoring free chloride concentration is using silver/silver chloride electrodes (Ag/AgCl). These electrodes are sensitive mainly to chloride ions and establish a certain electrochemical potential depending on the chloride ion activity in the environment. Although the functioning principles of these electrodes are well-established, their use in concrete is challenging when durability and practical engineering issues are considered. In order to be able to accurately determine free chloride content in concrete, it is important to evaluate the performance of Ag/AgCl electrodes (sensors) in strong alkaline environments i.e. those existing in non-carbonated concrete (pH~12–13.5). Furthermore the linear response of these sensors to a wide range of chloride concentrations in highly alkaline medium, as well as their sensitivity to pH changes, need a more in-depth investigation. In this paper the response of Ag/AgCl electrodes in simulated pore solutions having different chloride concentrations and different pH values was studied. The electrodes were calibrated in cement extract solution, distilled-water and simulated pore solution. The results show that at chloride concentrations of > 4 mM the effect of pH on the response of the sensors is insignificant which makes using Ag/AgCl sensors in concrete feasible i.e. this concentration is much lower than the generally reported thresholds for corrosion initiation. Keywords: Ag/AgCl electrode, cement extract solution, free chloride, pH value, pore solution. To reference this document use: http://resolver.tudelft.nl/uuid:95faa6e6-bfa9-4f7b-8e25-de4a55c2493a Publisher University College London Source Young Researchers’ Forum II: Construction Materials, London, UK, 19th February 2014 Part of collection Institutional Repository Document type conference paper Rights (c) The Author(s) Files PDF 315517.pdf 597.85 KB Close viewer /islandora/object/uuid:95faa6e6-bfa9-4f7b-8e25-de4a55c2493a/datastream/OBJ/view