Temperature dependence of the formation of the passivation layer on carbon steel in high alkaline environment of concrete pore solution

In this study, the formation and the strength of the passive layer on carbon steel in concrete pore solution were investigated for temperatures ranging from room temperature to 850 degrees C. Two sets of carbon steel specimens were first exposed to different temperatures for an hour. One group cooled to room temperature in the air and the other one in the water. The steel specimens were then immersed in concrete pore solution and the passive layer formed on the steelwas investigated. Results showed that in the extreme conditions, i. e. very high temperature, and water-cooled condition, the passive layer rarely formed on the steel. Increasing the exposure temperature led to a decrease in the thickness of the passive layer. This decrease was more apparent when steel was cooled in water compared to air cooled specimens. Results from this study contribute to the knowledge base that may be used to advance the state of the art in predictive models for steel reinforcement in concrete exposed to high temperatures (e.g., fire, power plants). (C) 2016 Elsevier B.V. All rights reserved.