Evaluation of chloride content in concrete by X-ray fluorescence

Determination of chloride content in concrete structures can be carried out by the X-ray fluorescence technique. However some problems affect measurement validity and limit the convenience of using XRF analysis when a limited number of determinations have to be performed. Measurements carried out on chloride contaminated concrete and mixtures of NaCl and concrete show the influence of distribution and grain size of chloride containing phase on analytical results. It is shown that chloride fluorescence intensity, at the same concentration level and at very low concentrations, is greatly reduced when chloride is present in the concrete matrix as NaCl salt instead of being dissolved in the concrete pore solution.