Investigation of concrete by means of micro-XRF
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Micro-XRF has developed into a powerful technique for material analysis. In this webinar we will discuss the analysis of concrete by elemental mapping of the surface of a drill core using the M4 TORNADO PLUS micro-XRF spectrometer. In particular, a comparison of the analytical performance between the excitation by different X-ray tube source materials will be shown, namely rhodium (Rh) and silver (Ag). The advantages and limitations of both possible configurations will be discussed.
Chlorine (Cl) is one of the most important elements to understand the aging and deterioration of modern concrete surfaces, as an increase in Cl leads to an expansion of the matrix, forming cracks and resulting in a loss of stability in any construction over time. Consequently, it is desirable to detect even small amounts of Cl in the matrix. For most micro-XRF applications Rh is the most versatile and favorable anode material. However, in this case, it has the major drawback that the Rh-L-lines overlap with the Cl-K-lines. Therefore, careful deconvolution of the peaks is a requirement to avoid false anomalies. Alternatively, a filter can be introduced in order to suppress the Rh-L-lines, however, this will reduce the sensitivity of the instrument for all light elements, including Cl. Therefore, utilizing an X-ray source that has no peak overlap with such a critical element, and ideally provides efficient X-ray excitation of Cl, is highly favorable. This is the case for using Ag as an anode material.
The data presented includes element intensity distribution maps showing the accumulation of Na and Cl as well as the corresponding depletion of K in those areas. Measurements with both anode materials will be compared, the counting statistics and contrast of the elements of interest will be discussed, and some basic information on the underlaying, so-called, ACL-reaction will be given.
In the practical part of the webinar we will show how to present the results of an acquired map. Different approaches to visualize positive and negative correlations will be shown. In addition, various approaches to extract semi-quantitative values, for example the Cl depth profile, will be presented.
Who should attend?
- Quality control specialists assuring the quality of cement and concrete in the lab and on-site
- Investigators of failure in concrete constructions
- Researchers in R&D