Relations between chloride determination in real concrete structures by X-ray fluorescence spectroscopy and by potentiometric titration

Abstract

The technique of X-ray fluorescence spectroscopy is a non-destructive method used in several applications in Civil Engineering for the qualitative and quantitative determination of chemical elements in different materials. This technique allows the analysis of materials by atomic excitations and identification of spectra obtained from defined wavelengths interpreted for each chemical element present in the material in a precise and fast quantification, optimizing characterization analysis in a laboratory. Although the benefits obtained from this technique are clear, problems regarding the quantification of chloride ion in concrete powder samples, obtained from real structures, end up, giving significant errors in relation to its quantification, which, in turn, overestimate the chloride concentration in the profiles more than 500%. In this way, this work presents a correlation between two methodologies using concrete powder samples from structures present in a marine environment for more than 40 years. These samples were analyzed by X-ray fluorescence spectroscopy and potentiometric titration techniques in order to establish a correlation between the methods. The obtained results showed that there is a relationship between both techniques with a determination coefficient close to 1.