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The laser induced breakdown spectroscopy (LIBS) is a combination of laser ablation and optical emission spectroscopy. Due to the possibility of direct measurements on the sample surface and a minimum of required sample preparation investigations of building materials can be conducted quite fast. In combination with a scanning technique (translation stage or scanning mirrors head) the element distributions are evaluated taking in to account the heterogeneity of the material. This is a significant advantage compared to standard procedures. LIBS measurements are also time and cost saving in comparison to standard methods. The automated measurement procedures minimise the liability for errors. All elements are detectable and after calibration results can be quantified. At BAM LIBS has been successfully applied for the investigation of distribution and transport of different ions in building materials. Quantitative measurements are performed for chlorine, sodium, potassium, sulphur, lithium and hydrogen. Beside this the identification of substances and the evaluation of quantitative ratios by means of an integrated marker are possible. An overview about the principle and the possibilities of LIBS investigations of building materials is presented and typical applications are shown. The LIBS technique is on the step from laboratory application to on-site analyses.
Laser-induced breakdown spectroscopy (LIBS) is a combination of laser ablation and optical emission spectroscopy. Due to the possibility of direct measurements on the sample surface with a minimum of sample preparation investigations of building materials can be conducted quite fast. In combination with a scanning technique (translation stage or scanning mirrors head) 2D element distributions of harmful species like chlorides and alkalis are evaluated with a sub-mm resolution. By scanning a surface of typically 100 mm x 100 mm the heterogeneity of the material may be considered. LIBS is capable to identify hot spots in element concentration with a resolution of 0.1 mm or even smaller. A LIBS-system for the on-site application on building materials is, in cooperation with system developers and companies which will use this technique for investigation on real structures, under test at BAM. We present an example. Further work will focus on providing guidelines to establish LIBS as a standard procedure for chemical investigations of building materials.
LIBS is on the step from a laboratory application to on-site analysis. A validated mobile LIBS-system for on-site application on building materials is under development at BAM in cooperation with industrial partners (system developers and companies), who will use this technique for investigation on building structures like bridges and parking decks. The system is designed to measure the content of harmful species like chlorine, sulfur or alkalis, to give the engineer a tool for the estimation of the condition of concrete structures and for quality assurance during concrete repair work on-site. In these work results of on-site measurements on a chloride contaminated bridge are shown. Further work will focus on providing guidelines to establish LIBS as a standard procedure for chemical investigations of building materials.