TY - CONF A1 - Millar, Steven A1 - Gottlieb, Cassian A1 - Wilsch, Gerd A1 - Günther, Tobias A1 - Völker, Tobias T1 - Chemische Zustandsanalyse von Stahlbetonbauwerken mit der laserinduzierten Plasmaspektroskopie (LIBS) N2 - Die chemische Analyse von Beton gehört bei der Ermittlung des Ist-Zustandes von Stahl- und Spannbetonbauwerken zu den grundlegenden Untersuchungen bei der Zustandserfassung. Der tiefenabhängige Chloridgehalt sowie der Karbonatisierungsfortschritt müssen bei der Bewertung des Ist-Zustandes, beim Instandsetzungsbedarf und ggf. bei der Planung eines erforderlichen Instandsetzungskonzeptes mit einbezogen werden. Seit Mitte der 1990er Jahre wird an der Bundesanstalt für Materialforschung und -prüfung die laserinduzierte Plasmaspektroskopie (engl. Laser-induced Breakdown Spectroscopy) – kurz LIBS – stetig für die chemische Analyse von Beton weiterentwickelt. In diesem Beitrag wird der aktuelle Stand der Forschung/ Technik und der Normungsarbeit präsentiert, sowie zukünftig mögliche Anwendungen vorgestellt. Mit den aktuellen LIBS-Systemen (mobiles LIBS-System sowie kommerziell erhältliche Laborsysteme) ist es möglich den Chloridgehalt ortsaufgelöst in wenigen Minuten zu quantifizieren, sogenannte Elementlandkarten zu erstellen und somit die Elementverteilung innerhalb des Betons zu visualisieren. Durch das Scannen eines Bohrkernquerschnittes und der simultanen Erfassung von mehreren Elementen mit einer Messung, ist es zudem möglich, die Gesteinskörnung in den Messdaten zu identifizieren und den Chloridgehalt auf die Zementsteinmatrix zu beziehen. Fehlerquellen aus der Umrechnung der betonbezogenen Chloridgehalte können dadurch minimiert werden. Neben den Grundlagen von LIBS werden vor allem aktuelle Praxisbeispiele vorgestellt, die die aktuellen Möglichkeiten des Verfahrens veranschaulichen. T2 - 9. Kolloquium Parkbauten CY - Esslingen, Germany DA - 04.02.2020 KW - LIBS KW - Chemische Analyse KW - Spektroskopie KW - Beton PY - 2020 UR - https://elibrary.narr.digital/article/99.125005/kpb202010305 SN - 2510-7763 VL - 9 IS - 1 SP - 305 EP - 319 AN - OPUS4-50615 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilsch, Gerd A1 - Völker, Tobias T1 - Laser-based building material sorting for the processing of construction and demolition waste for the circular economy N2 - A joint project of partners from industry and research institutions for the research and construction of an analysis system for an automated, sensor-supported sorting of construction and demolition waste will be presented. This is intended to supplement or replace the previously practiced manual sorting, which harbors many risks and dangers for the staff and only enables obvious, visually detectable differences for separation. The method of laser-induced breakdown spectroscopy is to be used in combination with hyperspectral sensors. Due to the jointly processed information (data fusion), this should lead to a significant improvement in the separation of types. In addition to the sorting of different materials (concrete, main masonry building materials, organic components, glass, etc.), impurities such as SO3-containing building materials (gypsum, aerated concrete, etc.) could also be detected and separated. The subsequent recycling and sales opportunities are examined, such as the use of recycled aggregates in concrete, the recycling of building materials containing sulphate as a gypsum substitute for the cement industry or the agglomeration of synthetic lightweight aggregates for lightweight concrete or as a substrate for green roofs. At the same time, it is investigated whether soluble components (sulfates, heavy metals, etc.) can be detected by LIBS without a wet chemical analysis and what impact the recycling materials have on the environment. The entire value chain is examined using the example of the Berlin location in order to minimize economic / technological barriers and obstacles on a cluster level and to sustainably increase the recovery and recycling rates. T2 - Materials Week 2021 CY - Online meeting DA - 07.09.2021 KW - Laser induced breakdown spectroscopy KW - Building waste KW - Circular economy KW - Material sorting PY - 2021 AN - OPUS4-53286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - Round robin test for chloride analysis in cement pastes with LIBS N2 - In civil engineering, clear regulations and standards, such as the European standard DIN EN 206 apply to ensure that the existing infrastructure is sufficiently resistant to a wide range of exposure conditions. Despite these regulations, in practice concrete structures often show severe damage during their service life. One of these damages is pitting corrosion of the reinforcement, which can be caused by chloride ingress into the structure. Therefore, determining the distribution and depth of chloride ingress is important in predicting the service life. LIBS provides an alternative method to conventional wet chemistry in civil engineering. Despite many advantages, the use of LIBS has been severely limited due to a lack of regulations. Together with project partners from research and industry, we are currently working on a leaflet that will regulate chloride analysis in civil engineering using LIBS. This year, an international round robin test was organized to evaluate the performance of LIBS for chloride analysis in cement pastes. No specifications were given for the experimental LIBS setup and data evaluation. The preliminary results are presented. T2 - 11th Euro-Mediterranean Symposium on Laser-Induced Breakdown Spectroscopy (EMSLIBS) CY - Online meeting DA - 29.11.2021 KW - LIBS KW - Cement KW - Chloride KW - Round robin KW - Interlaboratory comparison PY - 2021 AN - OPUS4-53898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - Application of LIBS to identify construction and demolition waste for circular economy N2 - Responsible treatment of the environment and resources is a key element of sustainability. The building and construction industry is one of the largest consumers of natural resources. Consequently, there is a particular need for regulations and technologies that help to create closed material cycles. From the technological point of view, such efforts are complicated by the growing material diversity and the amount of composites contained in present and future construction and demolition waste (CDW). Nowadays, simple but proven techniques like manual sorting are mainly used. However, this practice not only poses health risks and dangers to the staff performing the work, but also relies on merely obvious, visually striking differences. Automated, sensor-based sorting of these building materials could complement or replace this practice to improve processing speed, recycling rates, sorting quality, and prevailing health conditions. The preliminary results for the identification of a wide variety of building materials with LIBS are presented. T2 - XII Laser Induced Breakdown Spectroscopy (LIBS 2022) CY - Bari, Italy DA - 04.09.2022 KW - LIBS KW - Construction and demolition waste KW - Circular economy PY - 2022 AN - OPUS4-55679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - Interlaboratory comparison for quantitative chlorine analysis in cement pastes with LIBS N2 - Concrete structures often show severe damage during their lifetime. One such damage is pitting corrosion of the steel reinforcement caused by chloride ingress into the porous concrete structure. Laser-induced breakdown spectroscopy (LIBS) is a promising method in civil engineering, which is used for detection of chlorine in concrete structures in addition to conventional methods of wet chemistry. To assess LIBS as a trustful analytical technique, its accuracy and robustness is carefully tested. The presentation will outline the results of the interlaboratory comparison of chlorine quantification in cement paste samples, which was carried out by 12 laboratories in 10 countries. Two sets of samples with chloride content ranging from 0.06-1.95 wt.% in the training set and 0.23-1.51 wt.% in the test sample set (“unknowns”), with additional variations in the type of cement and chlorine source (salt type) were sent to the laboratories. The overall result demonstrates that LIBS is suitable for the quantification of the investigated sample compositions: average relative bias was mostly below 15 %. Considering that the laboratories did not receive instructions on how to perform the analysis or how to process the data, the results can be evaluated as a true status quo of the LIBS technique for this type of analysis. T2 - XII Laser Induced Breakdown Spectroscopy (LIBS 2022) CY - Bari, Italy DA - 04.09.2022 KW - LIBS KW - Chlorine KW - Cement pastes KW - Interlaboratory comparison PY - 2022 AN - OPUS4-55680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Gornushkin, Igor B. T1 - Importance of physical units in the Boltzmann plot method N2 - The Boltzmann plot is one of the most widely used methods for determining the temperature in different types of laboratory plasmas. It operates on the logarithm as a function of the dimensional argument, which assumes that the correct physical units are used. In many works using the Boltzmann method, there is no analysis of the dimension of this argument, which may be the cause of a potential error. This technical note offers a brief description of the method and shows how to correctly use physical units when using transcendental functions like the logarithm. KW - Boltzmann plot KW - Laser induced plasma PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558039 DO - https://doi.org/10.1039/d2ja00241h SP - 1 EP - 3 PB - Royal Society of Chemistry AN - OPUS4-55803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - Laserbasierte Baustoffsortierung zur Aufbereitung von Bau und Abbruchabfällen für die Kreislaufwirtschaft (LIBS ConSort) N2 - Geschlossene Materialkreisläufe und sortenreine Materialfraktionen sind erforderlich, um hohe Verwertungs und Recyclingquoten in der Bauindustrie zu erreichen Beim Recycling von Bau und Abbruchabfällen wurden bisher bevorzugt einfache, aber bewährte Techniken eingesetzt, um große Mengen Bauschutt in kurzer Zeit zu verarbeiten Dies steht im Gegensatz zu den immer komplexer werdenden Verbundwerkstoffen in der Mineralbaustoffindustrie Die aktuell oft praktizierte händische Klaubung bürgt viele Risiken und Gefahren für das ausführende Personal und basiert lediglich auf offensichtlichen, visuell erkennbaren Unterschieden zur Trennung Eine automatisierte, sensorgestützte Sortierung dieser Baustoffe könnte diese Praxis ergänzen oder ersetzen, um die Verarbeitungsgeschwindigkeit, die Recyclingraten, die Sortierqualität und die vorherrschenden Gesundheitsbedingungen zu verbessern. T2 - ReMin Statuskonferenz 2023 CY - Clausthal Zellerfeld, Germany DA - 20.06.2023 KW - LIBS PY - 2023 AN - OPUS4-57752 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - LIBS ConSort Laserbasierte Baustoffsortierung zur Aufbereitung von Bau und Abbruchabfällen für die Kreislaufwirtschaft N2 - Geschlossene Materialkreisläufe und sortenreine Materialfraktionen sind erforderlich, um hohe Verwertungs und Recyclingquoten in der Bauindustrie zu erreichen Beim Recycling von Bau und Abbruchabfällen wurden bisher bevorzugt einfache, aber bewährte Techniken eingesetzt, um große Mengen Bauschutt in kurzer Zeit zu verarbeiten Dies steht im Gegensatz zu den immer komplexer werdenden Verbundwerkstoffen in der Mineralbaustoffindustrie Die aktuell oft praktizierte händische Klaubung bürgt viele Risiken und Gefahren für das ausführende Personal und basiert lediglich auf offensichtlichen, visuell erkennbaren Unterschieden zur Trennung Eine automatisierte, sensorgestützte Sortierung dieser Baustoffe könnte diese Praxis ergänzen oder ersetzen, um die Verarbeitungsgeschwindigkeit, die Recyclingraten, die Sortierqualität und die vorherrschenden Gesundheitsbedingungen zu verbessern. T2 - ReMin Statuskonferenz 2023 CY - Clausthal Zellerfeld, Germany DA - 20.06.2023 KW - LIBS PY - 2023 AN - OPUS4-57753 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völker, Tobias T1 - Laser Induced Breakdown Spectroscopy A Tool for Imaging the Chemical Composition of Concrete N2 - One of the most common causes of damage is the ingress of harmful ions into the concrete, which can lead to deterioration processes and affect structural performance. Therefore, the increasingly aging infrastructure is regularly inspected to assess durability. Regular chemical analysis can be useful to determine the extent and evolution of ion ingress and to intervene in a timely manner. This could prove more economical than extensive repairs for major damage, particularly for critical infrastructure. In addition to already established elemental analysis techniques in civil engineering such as potentiometric titration or X-ray fluorescence analysis, laser-induced breakdown spectroscopy (LIBS) can provide further important complementary information and benefits. The possibilities of LIBS are demonstrated using the example of a drill core taken from a parking garage. T2 - 6th International Conference on Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 03.10.2022 KW - LIBS KW - Concrete KW - Cement KW - Chlorine PY - 2022 AN - OPUS4-56061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilsch, Gerd A1 - Völker, Tobias A1 - Klewe, Tim A1 - Kruschwitz, Sabine T1 - Laser Induced Breakdown Spectroscopy – A Tool for Imaging the Chemical Composition of Concrete N2 - One of the most common causes of damage is the ingress of harmful ions into the concrete, which can lead to deterioration processes and affect structural performance. Therefore, the increasingly aging infrastructure is regularly inspected to assess durability. Regular chemical analysis can be useful to determine the extent and evolution of ion ingress and to intervene in a timely manner. This could prove more economical than extensive repairs for major damage, particularly for critical infrastructure. In addition to already established elemental analysis techniques in civil engineering such as potentiometric titration or X-ray fluorescence analysis, laser-induced breakdown spectroscopy (LIBS) can provide further important complementary information and benefits. The possibilities of LIBS are demonstrated using the example of a drill core taken from a parking garage. T2 - 6th International Conference on Concrete Repair, Rehabilitation and Retrofitting CY - Kapstadt, South Africa DA - 03.10.2022 KW - LIBS KW - Concrete KW - Chlorine PY - 2022 UR - https://iccrrr2022.org/downloads SP - 126 EP - 127 AN - OPUS4-56062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilsch, Gerd A1 - Völker, Tobias A1 - Klewe, Tim A1 - Kruschwitz, Sabine T1 - Laser-induced breakdown spectroscopy to investigate the chemical composition of concrete N2 - Laser-induced breakdown spectroscopy (LIBS) is a spectroscopic method for the analysis of the chemical composition of sample materials. Generally, the measurement of all elements of the periodic table is possible. In particular, light elements such as H, Li, Be, S, C, O, N and halogens can be measured. Calibration with matrix-matching standards allows the quantification of element concentrations. In combination with scanner systems, the two-dimensional element distribution can be determined. Even rough surfaces can be measured by online adjustment of the laser focus. LIBS can also be used on-site with mobile systems. Hand-held systems are available for point measurements. Common applications include the investigation of material deterioration due to the ingress of harmful ions and their interaction in porous building materials. Due to the high spatial resolution of LIBS and the consideration of the heterogeneity of concrete, the determination of precise input parameters for simulation and modelling of the remaining lifetime of a structure is possible. In addition to the identification of materials, it is also possible to assess the composition for example of hardened concrete, which involves the cement or aggregate type used. Other important fields of application are the detection of environmentally hazardous elements or the material classification for sorting heterogeneous material waste streams during dismantling. Non-contact NDT for “difficult to assess” structures as an example application through safety glass or in combination with robotics and automation are also possible. In this work, an overview of LIBS investigations on concrete is given based on exemplary laboratory and on-site applications. T2 - NDE NucCon 2023 CY - Espoo, Finland DA - 25.01.2023 KW - LIBS KW - Concrete KW - Chemical analysis PY - 2023 UR - https://www.aalto.fi/en/nde-nuccon-2023 SP - 351 EP - 359 AN - OPUS4-57303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Gornushkin, Igor B. T1 - Extension of the Boltzmann plot method for multiplet emission lines N2 - The Boltzmann plot method is widely used to determine the temperature of laser induced plasma. It involves the use of individual lines that are not easy to find in complex spectra and/or in the spectral range available. If the number of such lines is not enough to build a reliable Boltzmann plot, overlapping lines are often used, which are separated by software. However, line separation is a rather imprecise procedure, which, in addition, requires significant computational costs. This study proposes an extension of the Boltzmann plot method that allows a specific group of unresolved lines to be included in a Boltzmann plot without the need to separate them. This group of lines are multiplets, lines of the same element with similar upper and lower transition states. The multiplet lines along with the individual lines are included in the algorithm, which also includes a correction for self-absorption and is used to determine the plasma temperature. The algorithm is tested on synthetic spectra which are consistent with the model of a homogeneous isothermal plasma in local thermodynamic equilibrium and is shown to be superior to the standard Boltzmann plot method both in more accurate determination of the plasma temperature and in a significant reduction in the computational time. The advantages and disadvantages of the method are discussed in the context of its applications in laser induced breakdown spectroscopy. KW - LIBS KW - Spectroscopy KW - Boltzmann plot KW - Multiplet KW - Spectral overlap PY - 2023 DO - https://doi.org/10.1016/j.jqsrt.2023.108741 SN - 1879-1352 VL - 310 SP - 1 EP - 5 PB - Elsevier AN - OPUS4-58058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Gornushkin, Igor B. T1 - Investigation of a method for the correction of self-absorption by Planck function in laser induced breakdown spectroscopy N2 - The electron density and temperature of a laser-induced plasma can be determined from the width and intensity of the spectral lines, provided that the corresponding optical transitions are optically thin. However, the lines in laser induced plasma are often self-absorbed. One of the methods of correction of this effect is based on the use of the Planck function and an iterative numerical calculation of the plasma temperature. In this study, the method is further explored and its inherent errors and limitations are evaluated. For this, synthetic spectra are used that fully correspond to the assumed conditions of a homogeneous isothermal plasma at local thermodynamic equilibrium. Based on the error analysis, the advantages and disadvantages of the method are discussed in comparison with other methods of self-absorption correction. KW - LIBS KW - Self-absorption KW - Planck function PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572677 DO - https://doi.org/10.1039/D2JA00352J SN - 0267-9477 SP - 1 EP - 6 PB - Royal Society of Chemistry (RSC) AN - OPUS4-57267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Wilsch, Gerd A1 - Gornushkin, Igor B. A1 - Kratochvilo, L. A1 - Pořízka, P. A1 - Kaiser, J. A1 - Millar, S. A1 - et al., T1 - Interlaboratory comparison for quantitative chlorine analysis in cement pastes with laser induced breakdown spectroscopy N2 - Concrete structures experience severe damage during service, for example due to pitting corrosion of rebars caused by the ingress of chlorine (Cl) into the porous concrete structure. The ingress can be monitored using laser-induced breakdown spectroscopy (LIBS), a recently introduced civil engineering technique used to detect Cl in concrete structures in addition to conventional wet chemistry methods. The key advantages of LIBS are high spatial resolution, which is important when analyzing heterogeneous concrete samples, as well as the almost complete absence of sample preparation. To assess LIBS as a reliable analytical method, its accuracy and robustness must be carefully tested. This paper presents the results of an interlaboratory comparison on the analysis of Cl in cement paste samples conducted by 12 laboratories in 10 countries. Two sets of samples were prepared with Cl content ranging from 0.06 to 1.95 wt% in the training set and 0.23–1.51 wt% in the test set, with additional variations in the type of cement and Cl source (salt type). The overall result shows that LIBS is suitable for the quantification of the studied samples: the average relative error was generally below 15%. The results demonstrate the true status quo of the LIBS method for this type of analysis, given that the laboratories were not instructed on how to perform the analysis or how to process the data. KW - LIBS KW - Interlaboratory comparison KW - Round robin test KW - Cement KW - Chlorine PY - 2023 DO - https://doi.org/10.1016/j.sab.2023.106632 SN - 0584-8547 VL - 202 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-57102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Gottlieb, Cassian A1 - Kapteina, Gesa A1 - Wilsch, Gerd A1 - Millar, Steven A1 - Reichling, Kenji T1 - Neues DGZfP-Merkblatt B14: Quantifizierung von Chlorid in Beton mittels LIBS N2 - Bei der Erhaltung von Stahlbetonbauwerken ist der Chloridgehalt im Beton ein wichtiger Parameter zur Festlegung geeigneter Instandsetzungsmaßnahmen. Die bisher etablierten Verfahren basieren auf der nasschemischen Analyse einer Probe, Bohrmehl oder aufgemahlener Segmente eines Bohrkerns. Das Verfahren liefert einen Chloridgehalt je Tiefensegment, was mit einer starken Homogenisierung der Probe einhergeht, wodurch detaillierte Informationen zu Chloridunterschieden im Millimeterbereich verloren gehen. Eine alternative Methode ist die laserinduzierte Plasmaspektroskopie (LIBS), die nicht nur die quantitative ortsaufgelöste Bestimmung des Chloridgehalts im Bezug zur Zementmasse ermöglicht, sondern auch simultan detaillierte Informationen über die Verteilung vieler anderer chemischer Elemente liefert. Die räumliche Auflösung liegt in der Regel im Bereich von einigen Millimetern, kann aber bei Bedarf auf 0,1 mm oder weniger erhöht werden. Das neue Merkblatt B14 „Quantifizierung von Chlorid in Beton mit der laserinduzierten Plasmaspektroskopie (LIBS)“ der Deutschen Gesellschaft für Zerstörungsfreie Prüfungen (DGZfP) regelt und vereinheitlicht erstmals die zuverlässige und reproduzierbare Ermittlung des Chloridgehalts mit LIBS. In diesem Beitrag wird das Merkblatt vorgestellt und anhand praktischer Anwendungsbeispiele das Potenzial von LIBS für Fragestellungen in der Betonerhaltung verdeutlicht. KW - LIBS KW - Chlor KW - Chlorid KW - Beton KW - Bauwerksdiagnostik PY - 2024 DO - https://doi.org/10.1002/best.202400014 SP - 1 EP - 7 AN - OPUS4-60005 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Millar, Steven A1 - Strangfeld, Christoph A1 - Wilsch, Gerd T1 - Identification of type of cement through laser-induced breakdown spectroscopy N2 - The composition of concrete determines its resistance to various degradation mechanisms such as ingress of ions, carbonation or reinforcement corrosion. Knowledge of the composition of the hardened concrete is therefore helpful to assess the remaining service life of an existing structure or evaluate the damage observed during inspections. For example, for most existing concrete structures the type of cement originally used is not known and must therefore be determined afterwards. This paper presents a preliminary study on the application of laser-induced breakdown spectroscopy (LIBS) to identify the type of cement. For this purpose, ten different types of cement were investigated. For every type, three cement paste prisms were produced: (i) prisms dried, ground and pressed into tablets, (ii) prisms dried and (iii) prisms untreated. LIBS measurements were performed with a diode-pumped low energy laser (1064 nm, 3 mJ, 1.5 ns, 100 Hz) in combination with two compact spectrometers which cover the UV and NIR spectral range. A reduced subset of spectral features was used to build a classification model based on linear discriminant analysis. The results show that the classification of homogenized pressed cement powder samples provides a high accuracy, however, factors such as a different sample matrix and moisture content can affect the accuracy of the classification. The study demonstrates that LIBS is a promising tool to identify the type of cement. KW - Spectroscopy KW - LIBS KW - Cement KW - Classification KW - Identification PY - 2020 DO - https://doi.org/10.1016/j.conbuildmat.2020.120345 VL - 258 SP - 120345 PB - Elsevier Ltd. AN - OPUS4-51157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völker, Tobias A1 - Gornushkin, Igor B. T1 - Mass and mole fractions in calibration-free LIBS N2 - This technical note highlights the fact that CF-LIBS algorithms work in mole fractions, while results of spectrochemical analysis are usually reported in mass fractions or mass percent. Ignoring this difference and not converting mole fractions to mass fractions can lead to errors in reported concentrations determined by the CF-LIBS method and inadequate comparison of these concentrations with certified concentrations. Here, the key points of the CF-LIBS algorithm are reproduced and the formulae for converting a mole fraction to a mass fraction and vice versa are given. Several numerical examples are also given, which show that the greater the difference between the molar mass of an individual element in a sample and the average molar mass, the greater the discrepancy between the mole and mass fractions. KW - Spectroscopy KW - Analytical Chemistry KW - LIBS KW - Calibration PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598611 DO - https://doi.org/10.1039/d4ja00028e SN - 0267-9477 VL - 39 IS - 4 SP - 1030 EP - 1032 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maack, Stefan A1 - Torrent, R. A1 - Ebell, Gino A1 - Völker, Tobias A1 - Küttenbaum, Stefan T1 - Testing to reassess – Corrosion activity assessment based on NDT using a prestressed concrete bridge as case-study N2 - Corrosion of concrete reinforcement is one of the major damage mechanisms affecting both the load-bearing capacity and the serviceability of re-inforced concrete structures significantly. When externally discernible damages are observed during visual inspections on the structure, the extent of the damage inside the concrete is often already significant. Corrosion caused by carbonation often leads to severe discoloration of the surface or even large-area spalling of the concrete cover. In contrast, chloride-induced corrosion is usually difficult to observe visually but can cause much more serious damage in less time. The effect occurs locally and can lead to weakening of the cross-section of the reinforce-ment. This, in turn, can cause sudden structural collapses without prior notice. In the meanwhile, various non-destructive and minimally invasive testing methods are available to evaluate the resistance to penetration of corrosion-pro-moting pollutants and to detect active corrosion. In this paper, a bridge crossing the river Regen is used as a case-study to demonstrate how the information ob-tained applying different testing methods can be combined and evaluated in the context of structural reassessments. Both the results of the permeability testing and the electrical resistance measurement are considered, as well as active corro-sion areas are localized using the half-cell potential mapping combined with the concrete cover measurement with the eddy current method and ground penetrat-ing radar. The results are evaluated using drill cores and in addition laser-induced breakdown spectroscopy was applied to obtain information about possible chlo-ride ion transport into the concrete. T2 - EUROSTRUCT 2021 – 1ST conference of the european association on quality control of bridges and structures - Eurostruct CY - Padova, Italy DA - 30.08.2021 KW - Nondestructive testing KW - Corrosion KW - Bridge KW - Durability assessment KW - Civil engineering PY - 2022 SN - 978-3-030-91876-7 SP - 1 EP - 9 PB - Springer International Publishing AN - OPUS4-54006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schwarz, W. A1 - Wilsch, Gerd A1 - Katsumi, N. A1 - Ebell, Gino A1 - Völker, Tobias T1 - Ion distribution in concrete overlay, mapped by laser induced breakdown spectroscopy (LIBS), modified by an embedded zinc anode N2 - Galvanic corrosion protection by embedded zinc anodes is an accepted technique for the corrosion protection of reinforcing steel in concrete. Galvanic currents flow between the zinc anode and the steel reinforcement due to the potential difference that is in the range of a few hundred mV. The ion distribution was studied on two steel reinforced concrete specimens admixed with 3 wt.% chloride/wt. cement and galvanically protected by a surface applied EZ-anode. On both specimens, a zinc anode was embedded and glued to the concrete surface by a geo-polymer-based chloride-free binder. At one specimen, the EZ-anode was operated for 2,5 years, the EZ-anode at the other specimen was not electrically connected to the reinforcement, this specimen serves as a reference. Both specimens have been stored under identical conditions. The ion distribution between the anode (EZ-anode) and cathode (steel reinforcement) was studied by laser-induced breakdown spectroscopy (LIBS) after 7 months, 12 months, and 2,5 years. Results of the LIBS studies on the specimen with activated EZ-anode after 7 months, 12 months, and 2,5 years and of the reference specimen after 2,5 years are reported. Results show that diffusion of ions contributes to the changes in the ion distribution but migration, especially of chlorides towards the EZ-anode is significant despite the weak electric field – several hundred millivolts - generated by the galvanic current. Results show that chloride ions accumulate near the zinc-anode as in water-insoluble zinc-hydroxy chlorides - Simonkolleit. T2 - ICCRRR 2022 CY - Capetown, South Africa DA - 03.10.2022 KW - Korrosion KW - Corrosion KW - LIBS KW - Zinc PY - 2022 AN - OPUS4-55948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwarz, W. A1 - Wilsch, Gerd A1 - Katsumi, N. A1 - Ebell, Gino A1 - Völker, Tobias T1 - Ion distribution in concrete overlay, mapped by laser induced breakdown spectroscopy (LIBS), modified by an embedded zinc anode N2 - Galvanic corrosion protection by embedded zinc anodes is an accepted technique for the corrosion protection of reinforcing steel in concrete. Galvanic currents flow between the zinc anode and the steel reinforcement due to the potential difference that is in the range of a few hundred mV. The ion distribution was studied on two steel reinforced concrete specimens admixed with 3 wt.% chloride/wt. cement and galvanically protected by a surface applied EZ-anode. On both specimens, a zinc anode was embedded and glued to the concrete surface by a geo-polymer-based chloride-free binder. At one specimen, the EZ-anode was operated for 2,5 years, the EZ-anode at the other specimen was not electrically connected to the reinforcement, this specimen serves as a reference. Both specimens have been stored under identical conditions. The ion distribution between the anode (EZ-ANODE) and cathode (steel reinforcement) was studied by laser-induced breakdown spectroscopy (LIBS) after 7 months, 12 months, and 2,5 years. Results of the LIBS studies on the specimen with activated EZ-anode after 7 months, 12 months, and 2,5 years and of the reference specimen after 2,5 years are reported. Results show that diffusion of ions contributes to the changes in the ion distribution but migration, especially of chlorides towards the EZ-anode is significant despite the weak electric field – several hundred millivolts - generated by the galvanic current. Results show that chloride ions accumulate near the zinc-anode as in water-insoluble zinc-hydroxy chlorides - Simonkollite. T2 - ICCRRR 2022 CY - Capetown, South Africa KW - Corrosion KW - LIBS KW - Zinc KW - Anode PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560576 DO - https://doi.org/10.1051/matecconf/202236404023 SN - 2261-236X VL - 364 SP - 1 EP - 7 PB - EDP Sciences CY - Les Ulis AN - OPUS4-56057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gottlieb, Cassian A1 - Gojani, Ardian A1 - Völker, Tobias A1 - Günther, Tobias A1 - Gornushkin, Igor B. A1 - Wilsch, Gerd A1 - Günster, Jens T1 - Investigation of grain sizes in cement-based materials and their influence on laser-induced plasmas by shadowgraphy and plasma imaging N2 - The effect of particle grain sizes in different cement-based mixtures on the laser-induced plasma evolution is studied using two experimental methods: (i) temporal and spatial evolution of the laser-induced shock wave is investigated using shadowgraphy and two-dimensional plasma imaging, and (ii) temporal and spatial distribution of elements in the plasma is investigated using two-dimensional spectral imaging. This study is motivated by the interest in applying laser-induced breakdown spectroscopy (LIBS) for chemical analysis of concrete, and subsequently obtain information related to damage assessment of structures like bridges and parking decks. The distribution of grain sizes is of major interest in civil engineering as for making concrete different aggregate grain sizes defined by a sieving curve (64mm to 0.125 mm) are needed. Aggregates up to a size of 180 μm can be excluded from the data set, therefore only the amount of small aggregates with a grain size below 180 μm must be considered with LIBS. All components of the concrete with a grain size smaller than 0.125mm are related to the flour grain content. Tested samples consisted of dry and hardened cement paste (water-cement ratio w/z=0.5), which served as a reference. Aggregate mixtures were made by adding flour grains (size 40 μm) and silica fume (size 0.1 μm) in different ratios to cement: 10%, 30%, 50% and 60%, all combined to the remaining percentage of dry or hydrated cement. The visualization results show that a dependance in the evolution of the plasma as a function of sample grain size can be detected only in the initial stages of the plasma formation, that is, at the initial 3 μs of the plasma life. Spectral information reveals the elemental distribution of the silicon and calcium in plasma, in both neutral and ionized form. Here also, a significant effect is observed in the first 1 μs of the plasma lifetime. KW - LIBS KW - Cement-based materials KW - Particle size KW - Shadowgraphy KW - Plasma imaging PY - 2020 DO - https://doi.org/10.1016/j.sab.2020.105772 VL - 165 SP - 105772 PB - Elsevier B.V. AN - OPUS4-50319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -