TY - CONF A1 - Wilsch, Gerd A1 - Gottlieb, Cassian A1 - Günther, Tobias A1 - Millar, Steven ED - Forde, Mike T1 - Application of laser induced breakdown spectroscopy N2 - A big part of the infrastructure is made of concrete, which is a multiphase system made of cement, aggregates, water and pores. Concrete is often used in combination with steel as reinforced concrete. Environmental influences, especially the ingress of harmful ions in combination with the ingress of water, trigger different damage processes which reduce the designed lifetime of a structure. The ingress of chlorides from de-icing salt or sea water leads to corrosion of the reinforcement. In addition, the carbonation of the concrete may trigger the corrosion of the reinforcement. The ingress of alkalis from deicing salts may cause the expansion of the amorphous silica aggregates (alkali-silica reaction) through formation of a swelling gel of calcium silicate hydrate if water is present. The ingress of sulphates may cause spalling of the concrete surface due to ettringite formation. For the standard procedure in civil engineering cores are taken, cut in slices, grinded and the obtained homogenized powder is solved in acid and investigated by standard procedures. BAM has developed the LIBS technique for the 2D evaluation of the chemical composition of concrete. The technique is established for automated laboratory use with high numbers of samples to investigate transport processes of harmful species (Cl-, CO2 , SO4 2-and alkalis) in concrete. Information about ingress depth and the quantitative values are important to estimate the remaining lifetime of the infrastructure. LIBS is a surface technique. To get information about the ingress depth, a drill core has to be taken and cut in the middle. The measurements are carried out at the cross section. The main advantages of LIBS are the direct measurement on the surface of the concrete, fast analysis (sample rate 100 Hz) with a spatial resolution of up to 100 µm, the consideration of the heterogeneity of the concrete and the possibility of automated measurements which save a lot of manpower and time. As an example the investigation of ingress profiles for standard diffusion and migration tests in civil engineering takes hours in comparison to just a few minutes using LIBS. At the same time a 2D-evaluation provides information about hot spots of elemental concentration which may not be found by standard methods. The state of the art of LIBS technique for applications in civil engineering will be presented, including typical results of 2D investigation of concrete in laboratory. The performance is also demonstrated by examples for onsite applications using a mobile LIBS system. The road map to standardization is presented as well. T2 - Structural Faults + Repair-2018 CY - Edinburgh, UK DA - 15.05.2018 KW - Sulphate KW - Chloride KW - Concrete KW - LIBS PY - 2018 SN - 0-947644-86-5 U6 - https://doi.org/10.25084/sfr.2018.0030 SP - 1 EP - 7 PB - University of Edinburgh CY - Edinburgh AN - OPUS4-46947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günther, Tobias A1 - Gottlieb, Cassian A1 - Völker, Tobias A1 - Millar, Steven A1 - Wilsch, Gerd T1 - Plasma reheating in LIBS with electric discharge to detect halogens in low concentrations N2 - The Laser-induced Breakdown Spectroscopy (LIBS) is an useful analytical technique for the chlorine detection in building materials, specifically in the reinforcement concrete. If chlorine exceeds a specific concentration threshold, the result can be pitting corrosion of the reinforcement, which affects the stability and lifetime of building structures like marine constructions, bridges or parking decks. The critical chlorine content based to cement is 0.4 wt.-% based to the cement for reinforced concrete. The ingress of chlorides from sea water or de-icing salt leads to corrosion of the reinforcement. The chlorine spectral line Cl I at 837.59 nm shows a good performance in helium atmosphere. For measurements without helium we used a electric discharge setup to reheat the Laser-induced plasma with a voltage below 100 V. In this case the reheating shows an increasing chlorine emission in air atmosphere. This work shows chlorine calibration curves with LIBS in a helium flow and LIBS with electric discharge reheating in air atmosphere. The determination of the limit of detection (LOD) for both setups and the measurement results of a drill core sample with a quantitative chlorine ingress profile will be presented. T2 - Xth international conference on Laser-Induced Breakdown Spectroscopy CY - Atlanta, GA, USA DA - 21.10.2018 KW - LIBS KW - Laser induced plasma KW - Plasma reheating KW - Electric discharge PY - 2018 AN - OPUS4-46797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günther, Tobias A1 - Millar, Steven A1 - Völker, Tobias A1 - Wilsch, Gerd T1 - Boosting of chlorine emission by electric discharge reheating in laser-induced plasma N2 - For the determination of the remaining life-time and the degree of damage of reinforced concrete structures such as marine construction, bridges or parking decks, a highly precise measurement of harmful species is also required for trace elements. One of the most interesting elements is chlorine, because above a certain threshold corrosion is triggered. To increase the intensity of the chlorine line, helium is usually used, which is costly. To overcome this problem, low electrical discharge reheating is used which operates in air atmosphere. A comparison between results obtained by measuring with helium and reheating by electrical discharge is presented. The performance is compared by the resulting calibration curves and the calculated limit of detection obtained by 15 reference samples based on cement with NaCl. Concentrations of reference samples range from 0.05 to 2.5 wt% chlorine. T2 - Xth international conference on Laser-Induced Breakdown Spectroscopy CY - Atlanta, GA, USA DA - 21.10.2018 KW - LIBS KW - Electric discharge KW - Plasma reheating PY - 2018 AN - OPUS4-46792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günther, Tobias A1 - Völker, Tobias A1 - Millar, Steven A1 - Wilsch, Gerd T1 - Spatially resolved determination of chloride content on rough surfaces using LIBS N2 - The durability and the lifetime of reinforced concrete structures can be drastically reduced by the influence of damage processes. One of the most common causes is chloride-induced corrosion, which is triggered by increased chloride content near the reinforcement. In a study, the chloride content should be determined directly at corrosion areas. The LIBS system used consists of a micro-chip laser (3 mJ, 100 Hz, 1.5ins) and two compact spectrometers covering the wavelength range of 177-355 nm (UV) and 750-940 nm (NIR). The analysis of the chloride content was carried out via the atomic chlorine spectral line 837.59 nm, using helium for signal amplification. Calibrations were carried out for quantitative chlorine measurements with 15 reference samples in the working range of 0.05 to 6.00 wt% chlorine. The calibration of the LIBS system was done according to DIN 32 645 and was tested for linearity. The determination of the quantitative chlorine contents was carried out on samples which were broken and thus have a high surface roughness. This requires real time correction of the focus point to compensate for the roughness of the samples. The poster shows spatially resolved element distributions and determined quantitative chloride concentrations near the corrosion Areas. T2 - Xth international conference on Laser-Induced Breakdown Spectroscopy CY - Atlanta, GA, USA DA - 21.10.2018 KW - LIBS KW - Rough surface KW - Chloride PY - 2018 AN - OPUS4-46791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilsch, Gerd A1 - Gottlieb, Cassian A1 - Günther, Tobias A1 - Völker, Tobias ED - Ludwig, H.-M. T1 - Schnelle quantitative Untersuchung von Elementverteilungen in Beton mittels LIBS N2 - Die Laserinduzierte Plasmaspektroskopie (engl.: Laser-induced Breakdown Spectroscopy, kurz: LIBS) ist eine Kombination aus Laserablation mittels eines energiereichen Laser-Pulses, der Erzeugung eines Plasmas auf der zu untersuchenden Oberfläche und dem quantitativen Nachweis der Elementzusammensetzung durch spektroskopische Untersuchung der vom Plasma emittierten Strahlung. Ein LIBS-Gerät liefert dem sachkundigen Planer Daten für die Bewertung des Ist-Zustandes von Bauwerken unserer Infrastruktur durch die zweidimensionale Erfassung von Elementverteilungen. Typische Anwendungen sind die Erfassung von Chlor, Schwefel, Kohlenstoff, Natrium, Kalium und Lithium in Beton oder als – Qualitätssicherung – der Nachweis der mit einem Marker versehenen Tiefenhydrophobierung. In Zusammenarbeit zwischen Industriepartnern und der BAM wurden ein Labor und ein mobiles LIBS-System für die Vor-Ort-Messungen entwickelt. Die Analyse erfolgt vollautomatisch. Die Ortsauflösung beträgt bis zu 0,1 mm x 0,1 mm. Es können Messflächen von 140 mm x 170 mm gescannt werden. Die Erstellung von 2D-Elementverteilungen im Beispiel unten benötigt weniger als 10 Minuten. T2 - ibausil - 20. Internationale Baustofftagung CY - Weimar, Germany DA - 12.09.2018 KW - LIPS KW - LIBS KW - Beton KW - Chlorid PY - 2018 SN - 978-3-00-059950-7 VL - 2 SP - 2380 EP - 2387 PB - F.A. Finger-Institut für Baustoffkunde, CY - Weimar AN - OPUS4-46779 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred A1 - Feldmann, Ines A1 - Günther, Tobias A1 - Wilsch, Gerd ED - Glaser, L. T1 - Analytische Untersuchungen an Glasmalfarben mittels EDX und LIBS N2 - Nach 1850 wurde zur weiteren Herabsetzung der Einbrenntemperatur von Glasmalfarben Borax (Na2B4O7 · 10 H2O) zugesetzt. Das Verhältnis war nun 1 Teil SiO2, 3 Teile PbO und 0,5 Teile Borax. Der analytische Nachweis von Bor in eingebrannten Malschichten war bisher jedoch nicht möglich.Daher wurden in Laborversuchen Glasmalfarben mit unterschiedlichem Gehalt an Borax auf Modellgläser aufgetragen, eingebrannt und anschließend unter simulierten Umweltbedingungen zeitraffend im Klimaschrank bewittert. Mit Hilfe von elektronenmikroskopischen Untersuchungen können Malschichten charakterisiert werden und somit Hinweise auf mögliche Schadensursachen liefern. Erste Versuche zum Nachweis von Bor erfolgten mit Hilfe von LIBS-Messungen (Laser Induced Breakdown Spectroscopy) an im Labor hergestellten Glasmalfarben mit unterschiedlichem Boraxgehalt. T2 - Archäometrie und Denkmalpflege 2018 CY - Hamburg, Germany DA - 20.03.2018 KW - Glasmalfarben KW - Umweltsimulation KW - Analytik PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-450664 SN - 978-3-945931-16-5 SN - 1435-8077 SP - 283 EP - 285 PB - Deutsches Elektronen -Synchrotron CY - Hamburg AN - OPUS4-45066 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gottlieb, Cassian A1 - Günther, Tobias A1 - Wilsch, Gerd T1 - Impact of grain sizes on the quantitative concrete analysis using laser-induced breakdown spectroscopy N2 - In civil engineering concrete is the most used building material for making infrastructures like bridges and parking decks worldwide. It is as a porous and multiphase material made of aggregates with a defined grain size distribution, cement and water as well as different additives and admixtures depending on the application. Different grain sizes are important to ensure the needed density and compressive strength. The resulting porous cement matrix contains a mixture of flour grains (aggregates with a grain size below 125 lm) and cement particles (particle size≈50lm). Harmful species like chlorides may penetrate together with water through the capillary pore space and may trigger different damage processes. The damage assessment of concrete structures in Germany is estimated due to the quantification of harmful elements regarding to the cement content only. In the evaluation of concrete using LIBS a two-dimensional scanning is necessary to consider the heterogeneity caused by the aggregates. Therefore, a LIBS system operating with a low energy NdCr:YAG laser, a pulse energy of 3 mJ, a wavelength of 1064 nm, a pulse width of 1.5 ns and a Repetition rate of 100 Hz has been used. Different Czerny-Turner spectrometers with CCD detectors in the UV and NIR range have been used for the detection. Large aggregates (macro-heterogeneity) can be excluded from the evaluation, whereas small aggregates in the range of the laser spot size (flour grains) cannot be spatially resolved. In this work the micro heterogeneity caused by flour grains and their impact on the quantification with LIBS will be discussed. To analyze the effect of changing grain sizes and ratios, the ablation behavior has been determined and compared. Samples with defined grain sizes were made and analyzed using LIBS. The grain size distributions were analyzed with laser diffraction (LDA). KW - LIBS KW - Concrete KW - Micro heterogeneity KW - Grain sizes PY - 2018 U6 - https://doi.org/10.1016/j.sab.2018.02.004 SN - 0584-8547 SN - 0038-6987 VL - 142 SP - 74 EP - 84 PB - Elsevier AN - OPUS4-44595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -