TY - JOUR A1 - Millar, Steven A1 - Gottlieb, Cassian A1 - Sankat, Nina A1 - Wilsch, Gerd A1 - Kruschwitz, Sabine T1 - Chlorine determination in cement-bound materials with Laser-induced Breakdown Spectroscopy (LIBS) – A review and validation JF - Spectrochimica Acta Part B-Atomic Spectroscopy N2 - The determination of chloride is still one of the main tasks for the evaluation of reinforced concrete structures. The corrosion of the reinforcement induced by the penetrating chlorides is the dominant damage process affecting the lifetime of concrete structures. In the recent years different research groups demonstrated that LIBS can be a fast and reliable method to quantify chlorine in cement-bound materials. Because chlorine in concrete can only occur as solved ions in the pore solution or bound in salts or hydrated cement phases, the detected emission of chlorine can be correlated with the chloride concentration determined e.g. with potentiometric titration. This work inter alia describes the production of reference samples and possible side effects during the production process. Due to transport processes in the porous matrix of the cement a misinterpretation of the concentrations is possible. It is shown how to overcome these effects and higher precisions of the single measurements can be realised. Using the calibration method, blank sample method and noise method, three different ways of calculating the limit of detection (LOD) and limit of quantification (LOQ) are compared. Due to the preparation of the reference samples a precision of the whole calibration model of sx0 = 0.023 wt% is determined. The validation of the model is based on different test sets, which are varying in their composition (different Cl-salts, water-to-cement ratios and additives). The determined mean error of the validation is 0.595 ± 0.063 wt%, which is comparable to standardised methods like potentiometric titration, direct potentiometry or photometry (0.40 ± 0.06 wt%) [1]. KW - LIBS KW - Chlorine KW - Cement KW - Calibration KW - Validation PY - 2018 DO - https://doi.org/10.1016/j.sab.2018.05.015 SN - 0584-8547 VL - 147 IS - September SP - 1 EP - 8 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-46558 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Millar, Steven A1 - Kruschwitz, Sabine A1 - Wilsch, Gerd T1 - Determination of total chloride content in cement pastes with laser-induced breakdown spectroscopy (LIBS) JF - Cement and Concrete Research N2 - The presented work discusses the accuracy of Laser Induced Breakdown Spectroscopy (LIBS) in determining the total chloride content in cement pastes. LIBS as an emission spectroscopy method is used to detect simultaneously several elements present in cement-based materials. By scanning surfaces the variability in the spatial distribution of elements can be visualised. However, for a quantification of the results, studies are necessary to characterise possible influences due to the wide variation of the chemical compositions in which cement can occur. It is shown how the calibration can be done, how the calibration samples were produced, and which statistical parameters are necessary to describe the precision of the regression. The performance of LIBS is estimated by detecting chloride in validation samples. Therefore, 55 samples and 7 ets with changing mix ompositions were produced. The presented study deals with possible influences of different mix compositions, ncluding different cations of chloride, varying w/c-ratios and the artial replacement of Portland cement with last furnace slag (50% BFS) and limestone (30% LS). Comparing the LIBS results with otentiometric titration, n accuracy of±0.05 wt%/total has been determined. KW - Spectroscopy KW - LIBS KW - Chloride KW - Quantification KW - Cement PY - 2019 DO - https://doi.org/10.1016/j.cemconres.2018.12.001 SN - 0008-8846 VL - 117 IS - March SP - 16 EP - 22 PB - Elsevier CY - Amsterdam AN - OPUS4-47059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -