Determination of Chloride in Hardened Portland Cement Paste,Mortar,and Concrete,

摘要

The severe distress observed in many portland cement concrete pavements and bridge decks exposed to sea water or to deicing salts has resulted in the need for a simple and accurate method for determining chloride content in hardened concrete. Most available methods are inaccurate either because volatile chlorine is lost or because the total quantity of chloride ion is not extracted. A method is presented in which the total chloride ion content is determined by dissolving the sample in 1plus 16nitric acid,filtering,and titrating with silver nitrate with the aid of a chloride-selective electrode. Volatilization of chloride during the digestion is avoided by gentle heating and careful control of the nitric acid concentration. (Modified author abstract)