TY - JOUR A1 - Powierza, Bartosz A1 - Stelzner, Ludwig A1 - Oesch, Tyler A1 - Gollwitzer, Christian A1 - Weise, Frank A1 - Bruno, Giovanni T1 - Water migration in one-side heated concrete: 4D in-situ CT monitoring of the moisture-clog-effect N2 - Explosive spalling due to fire exposure in concrete structures can lead severe damage and, in the worst case, to premature component failure. For this reason, an in situ investigation of water Migration in concrete due to surface heating was undertaken. During these experiments, a miniaturized concrete specimen within a confining and insulating double-hull was subjected to surface heating during simultaneous X-ray computed tomography (CT) scanning. Through the use of subtraction-based Image analysis techniques, it was possible to observe and quantify not only drying within areas of the concrete matrix close to the heated surface, but also the migration of moisture to both pore and matrix regions deeper within the specimen. It was also discovered that the correction of CT images for specimen deformation using DVC and variable detector performance using calibrated image filters significantly improved the quality of the results. This clearly demonstrates the potential of X-ray CT for evaluation of other rapid-density-change phenomena in concrete and other building materials. T2 - 8th Conference on Industrial Computed Tomography (iCT 2018) CY - Wels, Austria DA - 06.02.2018 KW - In-Situ X-ray CT KW - Digital Volume Correlation KW - Heated concrete KW - Water migration KW - Fire PY - 2019 DO - https://doi.org/10.1007/s10921-018-0552-7 SN - 1573-4862 SN - 0195-9298 VL - 38 IS - 1 SP - 15, 1 EP - 11 PB - Springer US CY - New York / Heidelberg AN - OPUS4-47147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pirskawetz, Stephan T1 - The burned shield-bearers: a detective story N2 - Severe fires at the Friedrichshain flak bunker in May 1945 destroyed or severely damaged an important part of the collection of the Kaiser-Friedrich-Museum, Berlin, today’s Bode Museum. Fragments of two marble sculptures by Tullio Lombardo, sculptor of the Italian renaissance, have survived and are now stored in the Bode Museum. In preparation for restoration, the condition of the sculptures has been documented in detail in 2010. The study revealed that the fragments are not stable enough to exhibit them in a horizontal nor in an upright position. The intention of a further study in 2012 was to find a correlation between ultrasonic velocity and mechanical properties of burned Carrara marble as a basis for stabilization measures. The results and numerous supplementary experiments show that the current condition of the sculptural fragments can not only be explained by the exposure to fire. KW - Marble sculptures KW - Marble deterioration KW - Fire KW - Ultrasonic velocities KW - Mechanical properties PY - 2018 DO - https://doi.org/10.1007/s12665-018-7267-z SN - 1866-6280 SN - 1866-6299 VL - 77 IS - 4 SP - Article 130, 1 EP - 12 PB - Springer-Verlag GmbH CY - Berlin Heidelberg AN - OPUS4-44159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Powierza, Bartosz T1 - Water Migration in One-Side Heated Concrete: 4D In-Situ CT Monitoring of the Moisture-Clog-Effect N2 - In order to study damage in concrete exposed to fire, a series of continuous X-ray computed tomography (CT) measurements were performed on a concrete sample heated, in-situ, on one side. The water migration relative to time and 3D space and, in particular, the dynamic condensation and vaporization of water droplets in the pores was quantified. This approach shows significant potential for further investigation of fire-related concrete damage. T2 - 8th Conference on Industrial Computed Tomography (iCT 2018) CY - Wels, Austria DA - 06.02.2018 KW - CT KW - X-ray KW - In-Situ KW - Pores KW - Heated Concrete KW - Water Migration KW - Fire PY - 2018 AN - OPUS4-46381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Souza, Roberto A1 - Knaust, Christian A1 - Andreini, M. A1 - La Mendola, S. T1 - Probability Distribution Sensitivity on the Thermo-Mechanical FEM of a Concrete Tunnel Exposed to Fire N2 - A probabilistic approach for finite element analysis (FEA) for tunnel linings exposed to the nominal fire is presented. The probabilistic FEA accounted for the uncertainties distributions tied to the conductivity and specific heat as well as of the compressive strength, tensile strength, Young’s modulus, and ultimate strain in compression. To get an understanding on the influence of different probability density functions on the distribution of maximum displacements of the tunnel lining, a sensitivity analysis was performed. Four sets of FEAs were carried out with different probability distributions of the conductivity, the specific heat, and the compressive strength of the concrete, respectively. An experimental design based on a Latin Hypercube Sampling algorithm was performed to define the input parameters which describe each analysis case. A reliability analysis was executed considering a limit state function based on the temperature-dependent ultimate strain. The results show that, depending on the distribution adopted, the standard deviation of the maximum displacements can vary up to 47,4% of the minimum standard deviation. The large standard deviation is associated with the possibility of a greater displacement and, hence, to a structure more vulnerable to fire. T2 - 4th Symposium Structural Fire Engineering Braunschweig CY - Brunswick, Germany DA - 12.09.2017 KW - Probabilistic analysis KW - Fire KW - Concrete KW - Finite elements analysis PY - 2017 SP - 1 EP - 13 AN - OPUS4-42681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Otremba, Frank T1 - Testing of pressurized vessels N2 - The results are based on data1. Figure 3 displays temperatures of the tank wall and of the gas phase over testing time. It can be seen that a complete coating strongly delayed the heating of tank wall and gas phase, whereas the partly coated tanks only had a minor influence on temperature development. There was no significant difference between a half coated and a thirdly coated tank measurable. Figure 4 shows the internal pressure of tanks over testing time. Only the fully coated tank enabled a low pressure over 90 min testing time. Hence, a complete coating is necessary to guarantee the fire safety of hazmat tanks and a partly coating is not sufficient. T2 - Annual Conference on Engineering and Information Technology CY - Nagoya - Japan DA - 29.03.2017 KW - Fire KW - Testing KW - Vessels KW - Dangerous goods PY - 2017 AN - OPUS4-39843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Otremba, Frank T1 - Pressure vessel subjected by fire N2 - Test facilities at BAM, Types of fire test, Vessel testing, Modelling of vessel response to fire, Current research, Future research T2 - COTEQ 2017 CY - Rio de Janeiro, Brazil DA - 15.05.2017 KW - Vessels KW - Fire KW - Modelling PY - 2017 AN - OPUS4-40307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaves Spoglianti de Souza, Roberto T1 - Probabilistic thermo-mechanical analysis of a concrete tunnel lining subject to fire N2 - A probabilistic finite elements analysis (FEA) of a tunnel lining subject to fire is presented. The probability distributions of the parameters related to the thermal analysis was considered in order to study the variability of the results and to carry out a reliability analysis. This assessment considered as random variables the thermo-mechanical properties of the concrete, the maximum heat release rate (HRR), the duration of the period of maximum HRR, the convective coefficient, the emissivity at the surface exposed to the fire, the air velocity within the tunnel, and the initial fire radius. The temperature-time curve was described by a correlation. An experimental design based on a Latin Hypercube Sampling algorithm was performed to define the input parameters to each analysis case. The definition of a limit state function based on the punctual strain status has permitted to carry out a reliability analysis. T2 - IFireSS 2017 – 2nd International Fire Safety Symposium CY - Naples, Italy DA - 07.06.2017 KW - Probabilistic analysis KW - Latin hypercube KW - Tunnel KW - Fire KW - Concrete PY - 2017 AN - OPUS4-40651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaves Spoglianti de Souza, Roberto A1 - Rosignuolo, Francesco A1 - Andreini, M. A1 - La Mendola, S. A1 - Knaust, Christian T1 - Probabilistic Thermo-Mechanical Analysis of a Concrete Tunnel Lining Subject to Fire N2 - Probabilistic thermo-Mechanical analysis of a concrete tunnel lining subject to fire The probability distributions of the parameters related to the thermal analysis was considered in order to study the variability of the results and to carry out a reliability analysis. This assessment considered as random variables the thermo-mechanical properties of the concrete, the maximum heat release rate (HRR), the duration of the period of maximum HRR, the convective coefficient, the emissivity at the surface exposed to the fire, the air velocity within the tunnel, and the initial fire radius. The temperature-time curve was described by a correlation. An experimental design based on a Latin Hypercube Sampling algorithm was performed to define the input parameters to each analysis case. The definition of a limit state function based on the punctual strain status has permitted to carry out a reliability analysis. T2 - IFireSS 2017 – 2nd International Fire Safety Symposium CY - Naples, Italy DA - 07.06.2017 KW - Probabilistic Analysis KW - Latin Hypercube KW - Tunnel KW - Fire KW - Concrete PY - 2017 SN - 978-88-89972-67-0 SN - 2412-2629 SP - 997 EP - 1004 PB - Doppiavoce CY - Naples, Italy AN - OPUS4-40652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosignuolo, F. T1 - A comparison between empirical models and FDS simulation to predict the ceiling gas temperature distribution in a tunnel fire N2 - A comparison between the results obtained from a Computational Fluid Dynamic (CFD) simulation and from the application of an empirical formula for determining the temperature distribution inside a tunnel in case of fire is presented. The temperature is measured and calculated at different distances from the location of the fire and at different time intervals. The fire considered varies with time following a time-heat release rate curve which has a parabolic growing phase, a constant period and a linear decay. The comparison reveals differences in the results. The temperatures calculated with the empirical formula resulted higher than the temperatures obtained by means of the CFD simulation. A list of possible reasons for this limited correspondence is also presented and commented. A proposal for further studies to better define the limitations of both the procedures and to define the influence of each parameter involved is finally presented. T2 - World Tunnel Congress 2017 – Surface challenges – Underground solutions CY - Bergen, Norway DA - 09.06.2017 KW - CFD KW - Fire KW - Tunnel KW - Design Fire PY - 2017 AN - OPUS4-40655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stelzner, Ludwig A1 - Powierza, Bartosz T1 - Thermisch induzierter Feuchtetransport in HPC T1 - Thermally induced Moisture Transport in structure density High-performance Concrete N2 - Die Entwicklung von leistungsfähigen Fließmitteln in den letzten Jahrzehnten ermöglicht die Herstellung von Beton mit sehr geringem w/z-Wert, bei gleichzeitig guter Verarbeitbar-keit. Die Reduzierung des w/z-Wertes geht dabei mit einer Erhöhung der Festigkeit und einer Verdichtung der Gefü-gestruktur einher. Aufgrund der hohen Druckfestigkeit finden diese Hochleistungsbetone vermehrten Einsatz im Hoch-, Brücken-, und Tunnelbau. Unter Brandbeanspruchung neigen diese Hochleistungsbetone allerdings zu explosionsartigen Abplatzungen. Diese werden nach derzeitigem Stand auf thermomechanische und thermohydraulische Prozesse zurückgeführt. Letztere beruhen auf der Generierung hoher Wasserdampfdrücke in einseitig brandbeanspruchten Beton-bauteilen, die zum einen auf die geringe Permeabilität des Hochleistungsbetons und zum anderen auf die Bildung einer wassergesättigten Zone, der sogenannten „moisture clog“ zurückzuführen sind. Dabei spielen Verdampfungs- und Kondensationsvorgänge sowie der vorhandene Temperatur-gradient eine wichtige Rolle. Die Interaktion des Feuchtetra-nsportes mit den Gefügeveränderungen während der thermi-schen Beanspruchung soll im Rahmen weiterer Versuche eingehend untersucht werden. Zur Analyse des Feuchtetransports während der thermischen Beanspruchung wurden miniaturisierte Prüfkörper aus Hoch-leistungsbeton hergestellt, die mit Hilfe eines elektrischen Heizelements einseitig erwärmt wurden. Zur Sicherstellung eines eindimensionalen Wärme- und Feuchtetransportes ist der Betonprüfkörper mit einer speziellen Glaskeramik und einer Hochtemperaturwolle ummantelt. Simultan zur Erwär-mung werden eine Reihe röntgentomographischer Aufnah-men durchgeführt. Durch Differenzbildung aufeinanderfol-gender Aufnahmen können Dichteveränderungen lokal und zeitlich aufgelöst werden. Diese lassen Rückschlüsse auf Än-derungen der Feuchteverteilung im Prüfkörper während der Erwärmung zu. Parallel dazu werden Untersuchungen mittels NMR-Relaxometrie (nuclear magnetic resonance) vor und nach der thermischen Beanspruchung durchgeführt. Diese Prüfmethodologie ermöglicht es erstmals, die Veränderungen der Feuchteverteilung infolge thermischer Beanspruchung im Hochleistungsbeton von den Gelporen bis hin zu vorhande-nen Verdichtungsporen abzubilden. So zeigen erste Ergebnis-se, dass die gewählten Untersuchungsmethoden Veränderun-gen der Feuchteverteilung im Prüfkörper räumlich und zeitlich auflösen können. KW - Abplatzen KW - Spalling KW - Brand KW - Feuchtetransport KW - Hochleistungsbeton KW - Röntgen-3D-Computertomographie KW - NMR KW - Fire KW - Moisture clog KW - Moisture transport KW - HPC KW - HSC KW - X-ray CT PY - 2017 DO - https://doi.org/10.1002/best.201700022 SN - 0005-9900 SN - 1437-1006 VL - 112 IS - 7 SP - 486 EP - 486 PB - Ernst & Sohn CY - Berlin AN - OPUS4-41826 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -