TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter T1 - CFD simulation to predict the performance of a peroxy-fuel burner N2 - new burner concept for peroxy-fuels is proposed. The performance of the proposed peroxy-fuel burner is predicted with the help of Computational Fluid Dynamics (CFD) simulation. It is found that peroxy-fuel burner not only requires considerable less amount of fuel for the same output/power but also at the same time the overall size of the processing unit can be reduced. As peroxy-fuels contain oxygen atoms within the molecule itself a similar to oxy-fuel combustion environment is created without even supplying pure oxygen. CFD simulations also support the above facts and demonstrate the existence of less favorable conditions to form NOx. T2 - 38th National conference on fluid mechanics and fluid power CY - Bhopal, India DA - 15.12.2011 KW - Burner KW - Peroxy-fuels KW - Performance KW - CFD simulation PY - 2011 IS - Paper HT-07 SP - 1 EP - 6 AN - OPUS4-25380 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sojref, Regine A1 - Güther, Wolfgang T1 - Solvent-based redispersion of fine (<200 nm) corundum powder pre-milled in water T2 - ECerS XII - 12th Conference of the European ceramic society CY - Stockholm, Sweden DA - 2011-06-19 KW - Powder processing KW - Redispersion KW - Tape casting KW - Corundum KW - Hydrophobization PY - 2011 SP - 1 EP - 4 AN - OPUS4-25379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helm, C. A1 - Eichler, Thorsten A1 - Raupach, M. A1 - Isecke, Bernd T1 - Time dependency of current and potential distribution during the cathodic protection of RC structures N2 - Cathodic protection (CP) is a common method for rehabilitation of reinforced concrete structures suffering from Chloride induced corrosion. A sufficient protection of the corroding rebar can be ensured by use of several protection criteria. The use of these assessment criteria, in particular the so called 100 mV-criterion, can lead to erroneous resuits for certain unconventional arrangements of rebar and cp anode. Therefore a joint research project of the Institute for Building Materials Research, RWTH-Aachen University, Germany, (ibac) and the Federal Institute for Materials Research and Testing, Berlin, Germany, (BAM) has been set up to determine the applicability of CP under arbitrary geometrical conditions. A special focus was set on the applicability of surface applied anode Systems for protection of the reinforcement of structures opposite to the accessible side (e.g. outer side of tunnel Shell, Bridge deck protected from inside a box girder) In this paper, the impact of the time dependent changes of the Polarisation behaviour of the rebar on the current and potential distribution is shown by means of parametric studies using the FEM method. T2 - EUROCORR 2011 - Developing solutions for the global challenge CY - Stockholm, Sweden DA - 04.09.2011 KW - Cathodic protection KW - Long time effects of cathodic polarisation KW - FEM-modelling KW - Steel in concrete PY - 2011 SP - 1 EP - 11 AN - OPUS4-25326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Chinta, P.K. A1 - Prager, Jens T1 - Computationally efficient ray tracing algorithm for simulation of transducer fields in anisotropic materials N2 - This contribution describes a computationally efficient ray tracing algorithm for evaluating transducer generated ultrasonic wave fields in anisotropic materials such as austenitic cladded and austenitic weld components. According to this algorithm, ray paths are traced during its propagation through various layers of the material and at each Interface the problem of reflection and transmission is solved. The presented algorithm evaluates the transducer generated ultrasonic fields accurately by taking in to account the directivity, divergence, density of rays, phase relations as well as transmission coefficients. The ray tracing algorithm is able to calculate the ultrasonic wave fields generated by a point source as well as a finite dimension transducer. The simulation results are compared quantitatively with the results obtained from Elastodynamic Finite Integration Technique (EFIT) on several configurations generally occuring in the ultrasonic non destructive testing of anisotropic materials. The excellent agreement between both models confirms the validity of the presented ray tracing algorithm. Finally, the ray tracing model results are also validated by means of experiments. T2 - NDE 2011 - National seminar & exhibition on non-destructive evaluation CY - Chennai, India DA - 08.12.2011 KW - Ultrasonic sound field KW - Ray tracing KW - Directivity KW - Anisotropy KW - Austenitic weld PY - 2011 SP - 482 EP - 486 AN - OPUS4-25329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. ED - Koenders, E.A.B. ED - Dehn, F. T1 - The mode of action of polypropylene fibres in high performance concrete at high temperatures N2 - It has been shown in fire tests that polypropylene fibres reduce or avoid explosive spalling of high performance concrete. In the critical temperature ränge up to 300 °C the permeability of HPC increases by using polypropylene fibre. Due to this the water vapour, which is the main reason for explosive spalling, can escape. There exist different theories in the literature conceming the micro structural mechanisms, which cause an increase in the permeability. Within the framework of an internal research project at BAM an innovative methodology was developed for experimental verifying of existing theories and to get new insights into this problem The methodology used is unique and has been undertaken here for the first time. This consists of the combination of acoustic emission and ultrasonic measurement during temperature loading and the non-destructive micro structural analysis of cooled down samples with the aid of micro X-ray computed tomography. For the validation of the nondestructive test methods scanning electron microscopic images of prepared samples were undertaken. The results show that due to the thermal decomposition of the polypropylene fibres micro canals emerge. These are connected due to a simultaneous micro cack formation. T2 - 2nd International RILEM workshop on concrete spalling due to fire exposure CY - Delft, The Netherlands DA - 05.10.2011 KW - Spalling KW - Polypropylene fibres KW - High performance concrete KW - Acoustic emission KW - X-ray computed tomography KW - Scanning electron microscopy PY - 2011 SN - 978-2-35158-118-6 SP - 289 EP - 296 PB - RILEM Publications AN - OPUS4-24835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miccoli, Lorenzo A1 - Perrone, C. A1 - Müller, Urs A1 - Gardei, André A1 - Ziegert, C. T1 - Comparison of mechanical behavior of different earth masonry typologies in cultural heritage N2 - The paper has been developed in the framework of a larger EC‐research program called NIKER, in which BAM and other seventeen research partners from the Mediterrean area are jointly involved. It aims to develop and validate innovative materials and technologies for the systemic improvement of the seismic behavior of Cultural Heritage assets. The death tolls brought about by recent catastrophes in developing countries where many inhabitants lived in earthen dwellings (Gujarat, India 2001, Bam, Iran 2003 and Concepción, Chile 2010 Earthquakes, Tamil Nadu 2004 Tsunami) have brought about research studies aimed at improving earth construction in terms of strength, seismic resistance and speed of construction. In comparison to the recent advances in research on stone and brick masonry, knowledge on the material properties and failure mechanisms of earthen Building construction is limited and scattered. The research presented here by aims making a comparison of mechanical behaviour between different earth masonry material typologies, consisting of earth block masonry, rammed earth and cob. T2 - WCCE-ECCE-TCCE Joint conference 2 - Seismic protection of cultural heritage CY - Antalya, Turkey DA - 31.10.2011 KW - Earth masonry KW - Material test KW - Cultural heritage KW - Seismic resistance PY - 2011 SN - 978-605-01-0188-1 SP - 25 EP - 36 AN - OPUS4-24836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Drochytka, R. ED - Bohus, S. T1 - Natural stone reprofiling in cultural heritage with modular repair mortars N2 - Whenever the preservation of original substance obtains priority in a restoration task, reprofiling techniques using repair mortars are a welcome solution. For ordinary concrete repair aesthetic aspects are of minor importance whereas for the restoration of natural stone elements they come to the fore. Especially for listed buildings and monuments, historico-cultural and aesthetical interests become the ruling Parameters for planning and execution of restoration tasks. Nevertheless the technical and constructive requirements have to be considered and deterioration processes have to be understood to ensure sustainability and durability of the repair task. Due o differences in the Chemical and mineralogical composition, natural stone provides a vast variety of texture and colour. Also the range of different mechanical and durability related properties is far wider than found with concrete for example. A research project dealing with the development of a modular repair mortar System for natural stone is currently set up at the BAM. To provide the conservator with the best possible options to match colour, texture and technical requirements, the System will be setup on a modular basis. Several different binder Systems on basis of cement, lime and sodium Silicate as well as polymer based Systems are planned, which can be combined with different aggregate compositions and different pigments. To evaluate the mortar performance, test procedures will be defined for tests on mortar samples and on composite specimens. In the paper the experimental Programme will be explained and first results will be presented and discussed. T2 - 2nd WTA - Internaitonal PhD Symposium - Building materials and buidling technology to preserve the built heritage CY - Brno, Czech Republic DA - 06.10.2011 PY - 2011 SN - 978-3-937066-21-9 SN - 0947-6830 N1 - Serientitel: WTA-Schriftenreihe – Series title: WTA-Schriftenreihe IS - 36 SP - 208 EP - 216 PB - WTA Publications AN - OPUS4-24837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chabrelie, A. A1 - Müller, Urs A1 - Scrivener, K.L. ED - Palomo, Á. ED - Zaragoza, A. ED - Agüí, J. C. L. T1 - Mechanisms of degradation of concrete by external sufate ions under laboratory and field conditions N2 - The durability of concrete is a major challenge for the construction, which devotes one third to one half of its annual investment to building maintenance. The lack of fieid data regarding concrete durability, especially in the case of exposure to Sulfate ions (“sulfate attack”) makes it dijficult to determine the appropriate fest methods andperformance criteria. Additionally, the increased use of sustainable blends (cement with mineral admixtures, typically slag from the iron industiy) suffers from a lack of experience regarding their long-term performance. Most results for sulfate resistance are derived from accelerated laboratoiy tests xvhere performance criteria are based only on macroscopic properties, especially expansion. To fill this gap and better widerstand the mechanisms of sulfate attack under real conditions, a parallel study of laboratoiy micro-concrete and fieid concrete samples under sulfate exposure was undertaken, focussing on microstructural changes in addition to the conventional macroscopic characterisation. Four exposure regimes were designed in the laboratoiy: full immersion (ponding), pH-control, semi-immersion and wet/diy cycles. Pure Portland blends and slag blends witli high level of slag replacement (70 wt.-%) were investigated. The exposure regime has been found to play a major role in the damage process. In ponding conditions, the damage process takes place in three stages characterised by a first period of induction, followed by surface damage thatfinally extends to the bulle of the material. Paradoxically, the w/c-ratio does not seem to have much impact on the ionic transport phenomena but might be more decisive in the microstructure mechanical strength against local stresses. The slag blends, considered as sulfate resistant in ponding exposure, revealed badperformances under wet/diy cycles. This beliaviour was attributed to poor proper physical resistance of the slag hydrates against diying. The fieid concretes selected for the comparison with the laboratoiy cases were partially buried in a sulfate-enriched soil in Argentina. A pure Portland blend and a slag blends with high level of slag replacement (80 wt.-%) were investigated. The submerged part of the samples could be compared to the laboratoiy ponding exposure, wliile the upper layer of the samples subjected to weathering could be compared to the laboratoiy wet/diy cycles exposure. The fieid obsen’ations tend to confirm the laboratoiy results and validate the fest settings. It has been underlined that a direct relationship between damage (e.g.; cracking/expansion) andphase assemblage was not evident. However, the study highlights that sulfate combination with the hydrates of the cement (e.g.; C-S-H) and with those of the slag would play a rote in the initiation of the expansion, which would be attributed to a swelling of the hydrates or to the precipitation offine ettringite after the Saturation level in sulfate of the hydrates has been reached. T2 - 13th International congress on the chemistry of cement - XIII ICCC CY - Madrid, Spain DA - 03.07.2011 KW - Sulfate attack KW - Exposure conditions KW - Concrete KW - Laboratory test KW - Field KW - Phase assemblage KW - Microstructure KW - XRD KW - SEM KW - SCM KW - Slag PY - 2011 SN - 978-84-7292-400-0 SP - 1 EP - 14 CY - Madrid AN - OPUS4-24810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pereira, F. A1 - Pistol, Klaus A1 - Korzen, Manfred A1 - Weise, Frank A1 - Pimienta, P. A1 - Carré, H. A1 - Huismann, Sven ED - Koenders, E.A.B. ED - Dehn, F. T1 - Monitoring of fire damage processes in concrete by pore pressure and acoustic emission measurements N2 - This paper presents the combined use of acoustic emission (AE), gas pore pressure and temperature measurements (PT). The simultaneous application of both techniques represents a new methodology in the context of fire spalling and contributes to a better understanding of the mechanisms of fire spalling, particular with regard to the interaction of micro cracking and pore pressure evolution. The study presents fire tests on normal strength concrete specimens with and without reinforcement at ISO Standard fire and at hydrocarbon (HC) fire. Supported by AE-analysis, it can be shown that due to the higher heating rate of the HC-fire in comparison to the ISO Standard fire the damage processes inside the concrete during the exposure are increased combined with augmenting the concrete permeability. As a consequence lower pore pressures were measured. However, despite the lower pore pressures, explosive spalling was observed. T2 - 2nd International RILEM workshop on concrete spalling due to fire exposure CY - Delft, The Netherlands DA - 05.10.2011 KW - Ordinary concrete KW - High temperature KW - Gas pore pressure KW - Acoustic emission KW - Spalling PY - 2011 SN - 978-2-35158-118-6 SP - 69 EP - 77 PB - RILEM Publications AN - OPUS4-24818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor A1 - Taffese, W.Z. A1 - Kumaran, G.S. A1 - Uzoegbo, H.C. A1 - Kühne, Hans-Carsten T1 - Inorganic binder systems for innovative panel technology in East Africa - possible ways to produce building materials from local raw materials N2 - Many African countries face serious problems associated with the rapid growth of urban Population and the resulting demand for affordable building materials. In search for appropriate Solutions to improve the Situation, the “LightSHIP” project was initiated, whose aims were to identify the required product specifications, to evaluate possible approaches and ultimately to develop new Building materials for East Africa. It was concluded that these materials should be produced in Africa mainiy from local raw materials; prefabricated, easily transportable construction elements are to be preferred. It is therefore reasonable to focus on artificial stones and partition boards. To be Independent of imported cement, it is suggested to make use of volcanic rocks, which are abundant in East African countries, for lime-pozzoian binders and geopolymers in the production of these construction elements. Future research activities should thus concentrate on assessment of the applicability of available volcanic rocks, the influence of their properties on the resulting binders and the design of appropriate binder-reinforcement-filler Systems. T2 - Workshop cement and concrete for Africa CY - Berlin, Germany DA - 17.08.2011 KW - Building materials KW - East Africa KW - Volcanic rock KW - Natural pozzolans KW - Lime-pozzolan binders KW - Geopolymers PY - 2011 SN - 978-3-9814281-4-8 SP - 32 EP - 36 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-24779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -