@misc{ScharfenbergMottokArtmannetal., author = {Scharfenberg, Georg and Mottok, J{\"u}rgen and Artmann, Christina and Hobelsberger, Martin and Paric, Ivan and Großmann, Benjamin and Pohlt, Clemens and Wackerbarth, Alena and Pausch, Uli and Heidrich, Christiane and Fadanelli, Martin and Elsner, Michael and P{\"o}cher, Daniel and Pittroff, Lenz and Beer, Stefan and Br{\"u}ckl, Oliver and Haslbeck, Matthias and Sterner, Michael and Thema, Martin and Muggenthaler, Nicole and Lenck, Thorsten and G{\"o}tz, Philipp and Eckert, Fabian and Deubzer, Michael and Stingl, Armin and Simsek, Erol and Kr{\"a}mer, Stefan and Großmann, Benjamin and Schlegl, Thomas and Niedersteiner, Sascha and Berlehner, Thomas and Joblin, Mitchell and Mauerer, Wolfgang and Apel, Sven and Siegmund, Janet and Riehle, Dirk and Weber, Joachim and Palm, Christoph and Zobel, Martin and Al-Falouji, Ghassan and Prestel, Dietmar and Scharfenberg, Georg and Mandl, Roland and Deinzer, Arnulf and Halang, W. and Margraf-Stiksrud, Jutta and Sick, Bernhard and Deinzer, Renate and Scherzinger, Stefanie and Klettke, Meike and St{\"o}rl, Uta and Wiech, Katharina and Kubata, Christoph and Sindersberger, Dirk and Monkman, Gareth J. and Dollinger, Markus and Dembianny, Sven and K{\"o}lbl, Andreas and Welker, Franz and Meier, Matthias and Thumann, Philipp and Swidergal, Krzysztof and Wagner, Marcus and Haug, Sonja and Vernim, Matthias and Seidenst{\"u}cker, Barbara and Weber, Karsten and Arsan, Christian and Schone, Reinhold and M{\"u}nder, Johannes and Schroll-Decker, Irmgard and Dillinger, Andrea Elisabeth and Fuchshofer, Rudolf and Monkman, Gareth J. and Shamonin (Chamonine), Mikhail and Geith, Markus A. and Koch, Fabian and {\"U}hlin, Christian and Schratzenstaller, Thomas and Saßmannshausen, Sean Patrick and Auchter, Eberhard and Kriz, Willy and Springer, Othmar and Thumann, Maria and Kusterle, Wolfgang and Obermeier, Andreas and Udalzow, Anton and Schmailzl, Anton and Hierl, Stefan and Langer, Christoph and Schreiner, Rupert}, title = {Forschungsbericht 2015}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-00-048589-3}, doi = {10.35096/othr/pub-1386}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-13867}, language = {de} } @article{SteindlSakoparnigBriendletal., author = {Steindl, Florian Roman and Sakoparnig, Marlene and Briendl, Lukas G. and Thumann, Maria and Galan, Isabel and Juhart, Joachim and R{\"o}ck, Rudolf and Saxer, Andreas and Mittermayr, Florian and Kusterle, Wolfgang}, title = {ASSpC - Vier Jahre Forschung f{\"u}r dauerhaften Spritzbeton}, series = {Bautechnik}, journal = {Bautechnik}, publisher = {Wilhelm Ernst \& Sohn}, address = {Berlin}, language = {de} } @article{ThumannChristlmeierHartmeieretal., author = {Thumann, Maria and Christlmeier, Peter and Hartmeier, Michael and Kusterle, Wolfgang}, title = {Reduzierung von versinterungsbedingten Reinigungsarbeiten in Tunneldr{\"a}nagen durch Optimierung der Spritzbetonrezeptur}, series = {Beton}, volume = {68}, journal = {Beton}, number = {11}, publisher = {VERLAG BAU + TECHNIK}, pages = {416 -- 421}, abstract = {Die Drainageleitungen in nicht druckwasserhaltenden Tunnelbauwerken haben die Aufgabe, anfallendes Bergwasser zu sammeln und aus dem Bauwerk zu f{\"u}hren. In den Leitungen treten h{\"a}ufig Kalkablagerungen, so genannte Versinterungen auf, die zu einem Teil- oder Vollverschluss der Rohre f{\"u}hren k{\"o}nnen und die Ableitung des Bergwassers be- bzw. verhindern. Zur Vermeidung von Sch{\"a}den am Tunnelbauwerk sind regelm{\"a}ßige und aufwendige Unterhaltsarbeiten notwendig. Ein wichtiger Einflussfaktor bei der Entstehung von Versinterungen ist der Kontakt des Bergwassers mit zementgebundenen Baustoffen, wie z. B. mit Spritzbeton. Aus dem Spritzbeton kann Calciumhydroxid ausgelaugt werden, das f{\"u}r den Korrosionsschutz der Bewehrung erforderlich ist, aber die Entstehung von Versinterungen beg{\"u}nstigen kann. Im Rahmen eines Forschungsprojekts wurden zahlreiche Mischungszusammensetzungen auf ihr Auslaugverhalten untersucht und Spritzbetonzusammensetzungen mit einem m{\"o}glichst geringen Versinterungspotenzial entwickelt.}, language = {de} } @inproceedings{KusterleThumann, author = {Kusterle, Wolfgang and Thumann, Maria}, title = {Pumpability of wet mixsprayed concrete with reduced clinker content}, series = {8th International Symposium on Sprayed Concrete : Modern Use of Wet Mix Sprayed Concrete for Underground Support, 11.- 14.06.2018, Trondheim, Norwegen}, booktitle = {8th International Symposium on Sprayed Concrete : Modern Use of Wet Mix Sprayed Concrete for Underground Support, 11.- 14.06.2018, Trondheim, Norwegen}, editor = {Beck, Thomas and Myren, Synn{\o}ve A. and Engen, Siri}, isbn = {978-82-8208-060-6}, abstract = {The research project „Advanced and Sustainable Shotcrete - ASSpC" aims at the improvement of sprayed concrete mix design regarding durability and sustainability. One possible improvement is to replace part of the clinker content in the binder with different supplementary cementitious materials. It is crucial that new mix designs fulfil the basic technical requirements on site concerning workability and early age development, too. One central issue of the project is to investigate which parameters influence the pumpability of sprayed concrete. Several test methods are used to determine the stability, tendency to segregation, bleeding and of course the consistency of concrete. An essential test method is a concrete sliding pipe rheometer (Sliper). This rheometer determines the pumping characteristics of concrete in the laboratory and on construction site. In comparison to other rheometers, the Sliper evaluates the rheological characteristics of the thin layer of paste which is lubricating the wall of the convey ing pipe. The paper presents the tests procedures in detail as well as first results from lab-tests and from site-tests with different advanced shotcrete mix-designs .}, language = {en} } @inproceedings{ThumannKusterle, author = {Thumann, Maria and Kusterle, Wolfgang}, title = {Durable and Sustainable Shotcrete - Requirements Concerning Workability and Early Strength Development}, series = {Shotcrete for Underground Support XIII : New Developments in Rock Engineering, Tunneling, Underground Space and Deep Excavation [Conference Sept. 3-6, 2017]}, booktitle = {Shotcrete for Underground Support XIII : New Developments in Rock Engineering, Tunneling, Underground Space and Deep Excavation [Conference Sept. 3-6, 2017]}, editor = {M{\"a}hner, Dietmar and Beisler, Matthias and Heimbecher, Frank}, abstract = {Nowadays there is a special need to develop "new" construction materials to reduce the environmental footprint of structures. Investigations focus on durability of constructions and the use of sustainable materials and the reduction of CO2 emission (especially of the binder). Constructions have to be sustainable and durable. This will lead to low maintenance work and costs as well as a good life cycle performance. The aim of the Austrian research project „Advanced and Sustainable Shotcrete - ASSpC" is to improve shotcrete mix design regarding durability and sustainability. There are different ways which may lead to success, one possibility is to replace part of the clinker content in the binder with supplementary cementitious materials. But it is crucial that new mix designs fulfil the technical requirements on site concerning workability and early age strength development, too. One central issue of the research project is to investigate how the pumpability of shotcrete can be determined in lab. At the moment there is no proven method available to measure the pumpability of shotcrete. Several test methods are used to determine the stability, tendency to segregation, bleeding and of course the consistency of concrete. Common test methods like the spread flow table and V-funnel flow time are used as well as two point test methods like the concrete rheometer eBT2 and Sliper. The segregation tendency is evaluated by the filter pressing test and the bucket setting test. Results from lab will be compared to results from site to define threshold values and parameters which describe the pumping characteristics of shotcrete base mix. In addition to that the early age strength development of the shotcrete mix design is investigated with the Minishot System designed by Sika. The shotcrete system is downscaled to a mini spray unit. In opposite to common test methods it is not necessary to mix the accelerator into the cement paste or mortar, but it will be added at the nozzle. The paste is sprayed by a downscaled nozzle and thus a realistic shear stress can be achieved. The paste is applied to a pulsment ultrasound spectrometer and the shear modulus development is measured continuously over time. The results can be linked to the strength development of shotcrete. The paper presents the tests procedures mentioned above in detail as well as first results with different shotcrete mix-designs.}, language = {en} } @inproceedings{ThumannKusterle, author = {Thumann, Maria and Kusterle, Wolfgang}, title = {Enhanced durability of shotcrete - Reduced potential for precipitations}, series = {Proceedings of the 11th fib International PhD Symposium in Civil Engineering. - 29.-31.08.2016, Tokyo, Japan}, booktitle = {Proceedings of the 11th fib International PhD Symposium in Civil Engineering. - 29.-31.08.2016, Tokyo, Japan}, editor = {Maekawa, Koichi and Kasuga, Akio and Yamazaki, Jun}, publisher = {Technical University of Tokyo}, isbn = {978-4-9909148-0-6}, pages = {221 -- 228}, abstract = {The contact of underground water with shotcrete leads to leaching of calcium hydroxide and can increase the precipitation of calcite in the secondary drainage system of tunnels under certain conditions. Indeed precipitations in the drainage pipes lead to high maintenance costs. Within a research project the leaching behavior of new and innovative binder compositions was tested in lab tests. One possible change in mix-design is the reduction in clinker content by using a lower amount of Ordinary Portland Cement together with cementitious materials. Successful combinations were further investigated in sprayed mortar and shotcrete tests to examine the influences of the spraying process and the addition of accelerator. The results indicate how shotcrete mix-design can be improved regarding its potential for precipitations and subsequently enhanced durability of shotcrete.}, language = {en} } @inproceedings{ThumannBriendlJuhartetal., author = {Thumann, Maria and Briendl, Lukas G. and Juhart, Joachim and Kusterle, Wolfgang}, title = {Rheologische Untersuchungen an Frischbetonmischungen f{\"u}r Spritzbeton}, series = {Rheologische Messungen an Baustoffen 2019 : Tagungsband zum 28. Workshop und Kolloquium, 13. und 14. M{\"a}rz an der OTH Regensburg}, booktitle = {Rheologische Messungen an Baustoffen 2019 : Tagungsband zum 28. Workshop und Kolloquium, 13. und 14. M{\"a}rz an der OTH Regensburg}, editor = {Teubert, Oliver and Kusterle, Wolfgang and Greim, Markus}, publisher = {tredition}, address = {Hamburg}, isbn = {978-3-7482-4651-0}, pages = {95 ff.}, language = {de} } @inproceedings{SteindlMittermayrThumannetal., author = {Steindl, F. and Mittermayr, Florian and Thumann, Maria and Juhart, Joachim and Galan Garcia, Isabel and Baldermann, Andre and Briendl, Lukas G. and Sakoparnig, Marlene and R{\"o}ck, Rudolf and Kusterle, Wolfgang}, title = {Sulfate resistance of dry mix shotcretes with new binder composition}, series = {ICCC 2019: 15th International Congress on the Chemistry of Cement, 16.-20.09.2019, Prague, Czech Republik}, booktitle = {ICCC 2019: 15th International Congress on the Chemistry of Cement, 16.-20.09.2019, Prague, Czech Republik}, pages = {3527 -- 3872}, abstract = {Improved understanding of the mechanisms underlying deleterious chemical attacks is necessary to better predict the long-term performance and durability of shotcrete in aggressive environments. In the scope of the research project "ASSpC - Advanced and Sustainable Sprayed Concrete", new durable and sustainable shotcretes and new test methods are developed. In order to increase shotcrete durability, the spray cement (specified in Austrian Guideline "Sprayed concrete") used is substituted with supplementary cementitious materials (SCMs). However, in the past SCMs have seen only limited use in the application of dry-mix shotcrete. This contribution presents 6 new mix designs intended to be used for dry-mix shotcrete, each with varying amounts and types of SCMs, and compares their performance and sprayability with a commercially available spray cement. As sulfate attack is one of the major threats to shotcrete (e.g. in tunnelling), the resistance of the new mixes against sulfate attack is tested using a modified version of the Swiss sulfate test according to SIA 262/1:2013. This approach provides new insights into damaging mechanisms of dry mix shotcrete in sulfate-loaded environments}, language = {en} } @inproceedings{BaldermannMittermayrThumannetal., author = {Baldermann, Andre and Mittermayr, Florian and Thumann, Maria and Kusterle, Wolfgang}, title = {Development of shotcrete with increased durability against thaumasite sulfate attack}, series = {ICCC 2019: 15th International Congress on Chemistry of Cement, 16.-20.09.2019, Prague, Czech Republik}, booktitle = {ICCC 2019: 15th International Congress on Chemistry of Cement, 16.-20.09.2019, Prague, Czech Republik}, pages = {3425 -- 3435}, language = {en} } @article{SakoparnigGalanSteindletal., author = {Sakoparnig, Marlene and Galan, Isabel and Steindl, Florian Roman and Kusterle, Wolfgang and Juhart, Joachim and Grengg, Cyrill and Briendl, Lukas G. and Saxer, Andreas and Thumann, Maria and Mittermayr, Florian}, title = {Durability of clinker reduced shotcrete: Ca2+ leaching, sintering, carbonation and chloride penetration}, series = {Materials and structures}, volume = {54}, journal = {Materials and structures}, publisher = {Springer Nature}, doi = {10.1617/s11527-021-01644-7}, pages = {1 -- 23}, abstract = {The reduction of clinker use is mandatory to lower the negative environmental impact of concrete. In shotcrete mixes, similarly to the case of conventional concrete, the use of supplementary cementitious materials (SCMs) and proper mix design allow for the substitution of clinker without compromising the mechanical properties. However, the impact of the substitution on the durability of shotcrete needs to be further assessed and understood. The results from the present study, obtained from real-scale sprayed concrete applications, show a reduction of the Ca2+ leaching and sintering potential of clinker-reduced shotcrete mixes due to the presence of SCMs. This positive effect, crucial for low maintenance costs of tunnels, is mainly related to a reduced portlandite content, which on the other hand negatively affects the carbonation resistance of shotcrete. Additionally, the hydration of SCMs positively influences the chloride penetration resistance presumably due to a combination of microstructural changes and changes in the chloride binding capacity. Differences found in the pore size distribution of the various mixes have low impact on the determined durability parameters, in particular compared to the effect of inhomogeneities produced during shotcrete application.}, language = {en} }