The fate of nitrate ions in concrete under the focus of corrosion inhibition

Calcium nitrate is used as an accelerating admixture to optimize performance of concrete and shorten the set time e.g. to counteract low temperature conditions, which slow concrete hydration. Up to this date the fate of nitrate ions in different types of the ASTM cements has been poorly quantified. Recent publications disclosed that nitrate ions have the ability to bind to certain solid phases, but also exist in the pore water and potentially act as a corrosion inhibitor. This research summarizes the fate of nitrate in different types of cements based on literature review and experiments conducted within this study. Also discussed is the impact of nitrate admixture on the corrosion inhibition and mineralogy of different types of cement and the influence of nitrate ions on the measurement methods such as rapid chloride permeation test or leaching.