@article{GalanBaldermannKusterleetal., author = {Galan, Isabel and Baldermann, Andre and Kusterle, Wolfgang and Dietzel, Martin and Mittermayr, Florian}, title = {Durability of shotcrete for underground support}, series = {Construction and building materials}, volume = {202}, journal = {Construction and building materials}, number = {March}, publisher = {Elsevier}, doi = {10.1016/j.conbuildmat.2018.12.151}, pages = {465 -- 493}, abstract = {Shotcrete is often used for the construction and stabilization of tunnels and other underground structures, where it is susceptible to different forms of physical and chemical attacks affecting its durability. An advanced understanding of the factors that limit the durability of shotcrete is crucial to develop tailored strategies for enhancing its service life. The main focus of this contribution is to shed light on the durability of shotcrete by revising the literature, highlighting what is missing and needs to be addressed, assessing how the knowledge about concrete durability can be transferred to shotcrete, and providing recommendations for durable shotcrete structures. (C) 2018 Elsevier Ltd. All rights reserved.}, language = {en} } @inproceedings{ParićKusterle, author = {Parić, I. and Kusterle, Wolfgang}, title = {Investigation, assessment and realtime readjustment of the rheological properties of SCC}, series = {SynerCrete'18 : Interdisciplinary Approaches for Cement-based Materials and Structural Concrete : Synergizing Expertise and Bridging Scales of Space and Time 24.-26. Oktober 2018, Funchal, Madeira Island, Portugal}, booktitle = {SynerCrete'18 : Interdisciplinary Approaches for Cement-based Materials and Structural Concrete : Synergizing Expertise and Bridging Scales of Space and Time 24.-26. Oktober 2018, Funchal, Madeira Island, Portugal}, editor = {Azenha, Miguel and Schlicke, Dirk and Benboudjema, Farid and Jędrzejewska, Agnieszka}, isbn = {978-2-35158-202-2}, pages = {255 -- 260}, abstract = {This paper discusses a new fresh concrete control system with the following structure: a rheometer measures the fresh concrete directly after the mixing process, during a short break. The viscosity and the dynamic yield point are determined by a ball rheometer. The rheological parameters viscosity and dynamic yield point describe the consistency and thus the pouring ability and consequently the quality of Self Compacting Concrete (SCC). Data collected from the measurement are the basis for an expert system which will help to readjust mixes with deviating rheology. Firstly, investigations were carried out during the development of different SCC mixtures in the COST TU 1404 Action. Secondly, investigations were done in two precast plants. A ball rheometer was installed in the respective mixers. The SCC for premium precast products was tested then during ongoing production. In addition, several test series were carried out in the laboratory of the OTH with the respective constitutive materials. During the test series, the mix designs of the well working SCC's were modified by using a deviating water content. Subsequently, using the rheological data, water, superplasticizer or stabilizing agents were added to the mix, trying to reach proper workability again. The graphs for the changing rheological properties as a function of the respective amount of start water content and additional water dosage or admixture dosage were generated and analyzed for the mixes of the two precast plants. With this information and experience, an expert system for the mix readjustment is currently under development.}, language = {en} } @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{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{GalanBriendlThumannetal., author = {Galan, Isabel and Briendl, Lukas G. and Thumann, Maria and Steindl, Florian and Roeck, Rudolf and Kusterle, Wolfgang and Mittermayr, Florian}, title = {Filler Effect in Shotcrete}, series = {Materials}, volume = {12}, journal = {Materials}, number = {19}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/ma12193221}, pages = {1 -- 24}, abstract = {The effects of fine limestone powder on the early hydration of cementitious systems accelerated by means of alkali-free aluminum sulfate based products, commonly used for shotcrete applications, were investigated in the course of laboratory and real scale tests. In binary (CEM I + limestone) and ternary (CEM I + limestone + slag) systems the addition of fine limestone led to an enhancement of the hydration degree and strength development at early times (<24 h). The formation of ettringite, aluminate hydrates, and C-S-H is affected by the joint action of the setting accelerator and the fine limestone. Accelerator and limestone, in combination with the cement, can be optimized to enhance ettringite and silicate reaction, in some cases coupled with aluminate reaction inhibition, to produce mixes suitable for sprayed concrete applications. Such optimization can help to reduce the cement content in the mixes without compromising the early strength development of the shotcrete.}, language = {en} } @inproceedings{SakoparnigGalanBaldermanetal., author = {Sakoparnig, Marlene and Galan, Isabel and Balderman, Andre and Steindl, Florian and Dietzel, Martin and Thumann, Maria and Saxer, Andreas and Kusterle, Wolfgang and Mittermayr, Florian}, title = {Experimental Ca leaching of shotcrete \& secondary precipitation}, series = {ICCC 2019: 15th International Congress on the Chemistry of Cement, ICCC 2019, 16.-20.09.2019, Prague, Czech Republik}, booktitle = {ICCC 2019: 15th International Congress on the Chemistry of Cement, ICCC 2019, 16.-20.09.2019, Prague, Czech Republik}, pages = {3488 -- 3495}, language = {en} } @inproceedings{BriendlGalanSteindletal., author = {Briendl, Lukas G. and Galan, Isabel and Steindl, Florian and R{\"o}ck, Rudolf and Thumann, Maria and Juhart, Joachim and Baldermann, Andre and Mittermayr, Florian and Kusterle, Wolfgang}, title = {Hydration processes of accelerated cementitious systems governing early strength development}, 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 = {714 -- 724}, language = {en} } @inproceedings{JuhartBriendlRoecketal., author = {Juhart, Joachim and Briendl, Lukas G. and R{\"o}ck, Rudolf and Galan, Isabel and Thumann, Maria and Mittermayr, Florian and Kusterle, Wolfgang}, title = {Performance optimization of shotcrete by combined fillers}, series = {ICCC 2019: 15th International Congress on the Chemistry of Cement, ICCC 2019, 16.-20.09.2019, Prague, Czech Republik}, booktitle = {ICCC 2019: 15th International Congress on the Chemistry of Cement, ICCC 2019, 16.-20.09.2019, Prague, Czech Republik}, pages = {1387 -- 3872}, language = {en} }