TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Krakow, Lutz A1 - Brigzinsky, Maria T1 - Asche Ton Komposite - Baukeramik ohne Trocknen und Brennen T2 - Tagungsbericht, IBAUSIL, 18. Internationale Baustofftagung, 12. - 15. September 2012, Weimar Bauhaus-Universität, Teil 2 Y1 - 2013 SN - 978-3-00-034075-8 PB - F.-A.-Finger-Inst. CY - Weimar ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Brigzinsky, Maria T1 - An alternative alumino-silicate binder based on the "just add water method" T2 - ICCM, 10th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete, 2017, Montreal, Kanada N2 - Alumino silicate compounds are important for alternative binders for concretes because of the reduction of CO2 and resource conservation. Such multi-phase systems consist of a solid component, such as e.g. slag, ash, calcined clays and others, and a liquid component, in generally highly concentrated alkaline solutions (water glass or NaOH/KOH). Because of safety and other reasons, such systems exclude large-scale practical applications. The newly developed alternative binder consists of a highly soluble silicate waste material, which is not common in geopolymere production, and a powdered Al-provider. It is called alumino silicate network (ASN) binder. Both components can be mixed dry in different ratios. Only after addition of water, a polymerization process is induced and the formation of amorphous phases, and sometimes zeolites can be observed. Mortar bars were produced and tested for different properties. The best results regarding to workability, strength development and sustainability were obtained with a molar Si/Al ratio of 2:1 in combination with fine-grained rock filler components. Investigations on the hardening process showed, that the mechanical properties varied over a wide range. Strength reserves, a ratio between compressive and tensile strength of approx. 3 and so far good resistance against acid solutions allow the use as a binder in high performance mortar and concrete structures. KW - alternative binders KW - geopolymere KW - alumino silicate structures KW - Si/Al ratio KW - industrial residues Y1 - 2017 UR - https://www-docs.b-tu.de/fg-baustoffe/public/Supp_320_24.pdf PB - RILEM ER - TY - CHAP A1 - Kositz, Mario A1 - Hünger, Klaus-Jürgen T1 - A predicitve model for the assessment of aggregate sensitivity to ASR T2 - ICCM, 10th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete, 2017, Montreal, Kanada N2 - Different aggregates stored in alkaline solutions have different solubility of silica and alumina. The dissolved silica reacts with water and alkalis to form an alkali silica gel, which can swell. ASR swelling can be reduced or prevented, if enough space is available for the alkali silica gel formation. This “space” is the open porosity, which can also be determined directly at the aggregate grains. Concrete specimens made with different aggregates were produced. They all were stored in a fog chamber at 104°F (40°C) and the ASR swelling was measured for one year. At the same time, the aggregates were stored in 0.1 mol KOH solution at 176°F (80°C) for 56 d only. The solubility of silica and alumina was determined continuously by ICP-OES. The obtained dissolution rates, open porosity and expansion data were compared and a reliable model for predicting the ASR sensitivity of concrete aggregates was derived. KW - alkali silica reaction KW - modeling KW - aggregate reactivity KW - dissolution of silica and alumina KW - dissolution rate KW - open porosity Y1 - 2017 UR - https://www-docs.b-tu.de/fg-baustoffe/public/Supp_320_24.pdf PB - RILEM ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Hübert, Cornelia A1 - Scholz, Yvonne A1 - Kronemann, Jens T1 - Changes of pore solution composition under accelerated mortar bar and concrete prism test conditions T2 - ICAAR, 14th International Conference on Alkali Aggregate Reaction, May 20-25, 2012, Austin, TX N2 - Accelerated tests of mortar bars and concrete prism were carried out at temperatures ≥ 40°C in order to reduce the test duration. Because the OH-/SO42- equilibrium is shifted to lower values with increasing temperature and alkali content of the cement, there exists the possibility of side reactions between sulphate ions from the cement and aluminate ions which can come from mineral admixtures and aggregates. Solubility measurements of two types of aggregates in sulphate free KOH solutions indicate that the temperature effect on the silica releasing rate is bigger than the inhibiting effect of the decreasing OH- concentration. To avoid side reactions during aggregate test procedure, expansion measurements should be performed at 40°C in combination with adapted solubility measurements. KW - pore solution KW - temperature KW - mineral admixture KW - solubility of aggregates Y1 - 2012 UR - https://www-docs.b-tu.de/fg-baustoffe/public/050_021811-HUNG.pdf ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Brigzinsky, Maria ED - Ludwig, Horst-Michael ED - Fischer, Hans-Bertram T1 - Zur Entwicklung eines alumosilicatischen Binders auf der Basis industrieller Reststoffe für den Bereich hochaggressiver Beanspruchungen T2 - Tagungsbericht, 20. Internationale Baustofftagung IBAUSIL, 12. - 14. September 2018, Weimar, Teil 1 N2 - Im Rahmen eines AiF-geförderten Forschungsprojektes wurde ein alumosilicatisches Bindersystem entwickelt, welches nur durch die Zugabe von Wasser zu einem Feststoff mit definierten Eigenschaften erhärtet. Ein wesentlicher Grundgedanke bei der Auswahl der Ausgangsstoffe war, industrielle Reststoffe zu verwenden, die verfügbar sind und beispielweise nicht über einen aufwändigen C alcinierprozess hergestellt werden müssen. Diese sollten andererseits aber eine sehr gute Löslichkeit besitzen, damit sich das hoch alkalische Milieu sofort nach Wasserzugabe einstellt und der alumosilicatische Strukturbildungsprozess unmittelbar in Gang gesetzt wird. Unterschiedliche silicatische und aluminatische Ausgangsmaterialien wurden getestet. Es wurde ein Stoffsystem unter Verwendung eines silicatischen Reststoffes aus der Glasproduktion in Kombination mit einer Natriumaluminatkomponente aus der Waschmittelproduktion entwickelt, welches die gestellten Anforderungen gut erfüllt. Dieses Stoffsystem dient gleichzeitig als Modell, an dem der Strukturbildungsprozess, der zur Bildung eines alumosilicatischen Netzwerkes (ASN) führt, z.B. mittels NMR-Untersuchungen untersucht werden kann. Im Unterschied zu den „klassischen“ Geopolymermaterialien Metakaolin, Hüttensand bzw. Flugaschen, ist das für den Strukturbildungsprozess entscheidende Verhältnis zwischen Si und Al in einem breiten Spektrum frei einstellbar und damit auch die mit dem Binder erzielbaren Eigenschaften variierbar. An Mörtel- und Betonprismen wurden zerstörungsfrei und zerstörend Festigkeiten und Formänderungen untersucht und Dauerhaftigkeitskennwerte bestimmt. Hohe mechanische Festigkeiten bis 60 N/mm2 Druckfestigkeit, aber insbesondere der sehr gute Widerstand gegen Säureangriffe machen Mörtel und Betone unter Verwendung des ASN-Binders interessant für Anwendungen im Bereich der Einwirkungen von aggressiven chemischen Reagenzien. Entsprechende Untersuchungen zum Säureangriff wurden durchgeführt und die Veränderungen mikroskopisch und mittels Eigenfrenquenzanalyse (Grindosonic) verfolgt. Y1 - 2018 SN - 978-3-00-059950-7 SP - 371 EP - 382 PB - F.A. Finger-Inst. für Baustoffkunde, Bauhaus-Univ. Weimar CY - Weimar ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Kositz, Mario A1 - Brigzinsky, Maria A1 - Ajami, Fouad T1 - A fast testing method to characterize ashes and ash mixtures using the ultrasonic technique T2 - Recent Advances in Concrete Technology and Sustainability Issues Proceedings Fourteenth International Conference Beijing, China October-November 2018 N2 - Fly ash is a typical mortar constituent in Germany, other European countries and worldwide. If cement alone is used as a binder, then the mortar is too expensive and cannot provide all properties. That`s why many companies have special recipes with fly ash, especially hard coal fly ash components, in the mortar. The aim of this project is to substitute such fly ashes by lignite coal fly ashes, which are cheaper, available at every times or have better properties. However this means, that the calcium free or calcium poor ash should be substituted by calcium rich ashes, which are not certificated because of fluctuations. To compensate the fluctuations in the ash compositions, several ashes are mixed. The European standard EN 450, which contains requirements, for example for the chemical composition of ashes, has to be taken into account. Fly ash mortar compound prisms have been produced and the different mechanical and deformation values were determined in comparison to a reference material. The basis for all experiments was the recipe of the company for a special mortar. An ash compound could be developed with the same workability by considering the economic reasons of the company. An important result too is that the fluctuations of the fly ash batches can be controlled by special developed chemical (color test) and physical (Ultrasonic velocity) test methods. Y1 - 2018 UR - https://www-docs.b-tu.de/fg-baustoffe/public/A%20fast%20test%20method%20for%20ashes-huenger.pdf ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Kositz, Mario A1 - Danneberg, Matti A1 - Radnik, Jörg T1 - XPS investigations on quartzite surfaces of natural rock samples for proof of Al exposure T2 - 27th Annual Conference of the German Crystallographic Society / Zeitschrift für Kristallographie. Supplement Y1 - 2019 SN - 978-3-11-065403-5 SN - 0930-486X VL - 39 SP - S. 110 PB - De Gruyter CY - Berlin ER - TY - CHAP A1 - Hünger, Klaus-Jürgen A1 - Acker, Jörg A1 - Danneberg, Matti A1 - Herold, Steven T1 - Quantification of stress states in quartzite surfaces by using RAMAN spectroscopy T2 - 27th Annual Conference of the German Crystallographic Society / Zeitschrift für Kristallographie. Supplement Y1 - 2019 SN - 978-3-11-065403-5 SN - 0930-486X VL - 39 SP - S. 122 PB - De Gruyter CY - Berlin ER - TY - GEN A1 - Hünger, Klaus-Jürgen A1 - Kurth, David T1 - Calcined Clays and Geopolymers for stabilization of loam structures for plaster and bricks T2 - Proceedings 3rd International Conferende on Calcined Clays for Sustainable Concrete, 15. - 17 Oktober 2019, Neu Delhi N2 - Loam is a very ecological building material with a great potential. It is found worldwide and completely recyclable. Under dry conditions, loam develops high strength values. However, loam is not moisture-resistant. Permanently acting moisture reduces the strength dramatically. The idea to improve the water resistance of loams is adding materials to the loam with the same basic structure. Therefore, Metakaolin, Calcined Clay, here so called Metaclay and a specially developed Geopolymer were selected. Blends of 4 different loams with different amounts of these additives were produced and tested. Criteria for an evaluation are the dynamical modulus of elasticity and the water resistance. These studies were supplemented by structural investigations using a light and a scanning electron microscope and XRD. The results are very interesting and the effects depends strongly on the kind of loam too. Not all additives lead to an improving of the mechanical properties. Nevertheless, not the samples with the highest mechanical values show the best water resistance behavior. Obviously, a balanced structure between loam and additive particles is necessarily. Such structures are not so dense but enough resistant to water to guarantee the positive property of fast water absorption and delivery of natural loams. The service lives of the loam prisms could be increased from certain minutes to several days. Best results are obtained with geopolymer based materials as an additive. This is not so surprising because both the loam and the geopolymer form alumino silicate structures during hardening. Y1 - 2019 UR - https://www-docs.b-tu.de/fg-baustoffe/public/Loam-Geopolymer-revised%20paper.pdf VL - III SP - 185 EP - 194 PB - RILEM ER - TY - GEN A1 - Hünger, Klaus-Jürgen A1 - Sander, Ingolf A1 - Zuckow, Natalia T1 - On the Workability of Mortar and Concrete Mixtures containing Calcined Clay Blends T2 - Proceedings 3rd International Conference on Calcined Clays for Sustainable Concrete, 15. - 17. Oktober, Neu Delhi N2 - Calcined Clays can be used in mortar and concretes as a part of a binder (LC3) or as a Supplementary Cementing Material (SCM). The aim here is to sub-stitute fly ash as an additive in concrete recipes. A stable mixture between two regionally available clays, burnt together with a certain ratio of 60 : 40 wt.-% at 650-680°C, could be produced. Such Metaclays produced in larger amounts were investigated in different mortar and concrete mixtures. The production indicates an important problem with the workability of the fresh concrete mixtures. That`s why different superplastizers were tested. It could be found that especially a mixture between a PCE- based material and a special additive, developed for loam sands provides very good results. The workability increases from less than 200 mm slump on a value of about 300 mm. The combination of calcined clay materials and special developed superplastizer mixtures allows producing concrete with very different properties. It can be a closed system for the production of durable concrete structures. KW - Calcined clay mixtures, Supplementary cementing material, worka-bility, superplastizers mixtures, precast concrete elements Y1 - 2019 UR - https://www-docs.b-tu.de/fg-baustoffe/public/Calcined%20Clay%20blends-Revised%20Paper.pdf VL - I SP - 207 EP - 215 PB - RILEM ER -