Calibration analysis of chloride binding capacity for cement-based materials under various exposure conditions

Abstract

This paper evaluated chloride binding capacity for cement-based materials through calibration analysis of Linear, Freundlich and Langmuir models with tested free and bound chloride ion contents in various concrete materials, cured by different methods, subjected to diverse exposure conditions. First, a dataset with 376 couples of tested free and bound chloride ion contents was assembled for various cement-based materials with either pre-mixed chlorides or externally-penetrated chlorides under simulated or natural atmospheric, tidal or submerged environments. Then, Linear, Freundlich and Langmuir binding models, which establish the relationship between bound and free chloride ion contents, were calibrated with the collected test data. The calibration results showed that Linear, Langmuir and Freundlich models could correlate well with free and bound chloride ion contents in cement-based materials with pre-mixed chlorides or externally-penetrated chlorides. Moreover, the recommendations for chloride binding capacity for cement-based materials by Linear, Langmuir and Freundlich models were proposed for cement-based materials with either pre-mixed or externally-penetrated or both chlorides. The calibrated binding models can contribute to accurate modeling of chloride penetration into cement-based materials.