TY - JOUR A1 - Galan, Isabel A1 - Briendl, Lukas G. A1 - Thumann, Maria A1 - Steindl, Florian A1 - Roeck, Rudolf A1 - Kusterle, Wolfgang A1 - Mittermayr, Florian T1 - Filler Effect in Shotcrete JF - Materials N2 - 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. KW - acceleration KW - ACCELERATORS KW - ALKALI-FREE KW - ALUMINUM SULFATE KW - CaCO3 KW - CALCIUM-CARBONATE KW - CEMENT HYDRATION KW - EARLY AGE HYDRATION KW - hydration KW - LIMESTONE POWDER KW - mechanical properties KW - PORTLAND-CEMENT Y1 - 2019 U6 - https://doi.org/10.3390/ma12193221 VL - 12 IS - 19 SP - 1 EP - 24 PB - MDPI CY - Basel ER - TY - CHAP A1 - Sakoparnig, Marlene A1 - Galan, Isabel A1 - Balderman, Andre A1 - Steindl, Florian A1 - Dietzel, Martin A1 - Thumann, Maria A1 - Saxer, Andreas A1 - Kusterle, Wolfgang A1 - Mittermayr, Florian T1 - Experimental Ca leaching of shotcrete & secondary precipitation T2 - ICCC 2019: 15th International Congress on the Chemistry of Cement, ICCC 2019, 16.-20.09.2019, Prague, Czech Republik Y1 - 2019 UR - https://iccc-online.org/fileadmin/gruppen/iccc/proceedings/ICCC15_2019.pdf SP - 3488 EP - 3495 ER - TY - CHAP A1 - Briendl, Lukas G. A1 - Galan, Isabel A1 - Steindl, Florian A1 - Röck, Rudolf A1 - Thumann, Maria A1 - Juhart, Joachim A1 - Baldermann, Andre A1 - Mittermayr, Florian A1 - Kusterle, Wolfgang T1 - Hydration processes of accelerated cementitious systems governing early strength development T2 - ICCC 2019: 15th International Congress on Chemistry of Cement, 16.-20.09.2019, Prague, Czech Republik Y1 - 2019 SP - 714 EP - 724 ER - TY - CHAP A1 - Steindl, Florian A1 - Galan, Isabel A1 - Baldermann, Andre A1 - Sakoparnig, Marlene A1 - Dietzel, Martin A1 - Röck, Rudolf A1 - Kusterle, Wolfgang A1 - Mittermayr, Florian T1 - Dauerhaftigkeitsuntersuchungen an Trocken- und Nassspritzbetonen mit mineralischen Zusatzstoffen - Investigations on the durability of dry- and wet-mix sprayed concrete with mineral additions T2 - Spritzbeton-Tagung 2021, 21. + 22. Jänner 2021, Alpbach Tirol N2 - Die Dauerhaftigkeit von Spritzbeton kann, insbesondere in seiner Verwendung als Stütz-und Ausbaumaterial im Tunnelbau, durch chemische Angriffe deutlich herabgesetzt werden. Im Forschungsprojekt "Entwicklung neuer dauerhafter und nachhaltiger Spritzbetone (ASSpC)" wurden Prüfkörper von Trocken-und Nassspritzbetonen in Großspritzversuchen hergestellt. Der Sulfatwiderstand und das Lösungsverhalten der Betone in sulfathaltigen wässrigen Lösungen wurden mit drei Testverfahren bestimmt und die Ergebnisse miteinander verglichen: Ein Pulvertestverfahren zeigt die Auflösung von Zementhydratphasen zugunsten der Neubildung von Calcit und Ettringit. Das Ausmaß der Sulfatdehnung an Bohrkernen, ermittelt im zweiten Testverfahren, korrespondiert mit dem chemischen Verhalten des gemahlenen Materials, insbesondere bezüglich der Reaktivität von calcium-und aluminium-haltigen Hydratphasen. Der Thaumasitwiderstand, ermittelt über Masseverlust von Prüf-körpern, zeigte eine weitgehende Übereinstimmung mit den zuvor genannten Tests. Die Verwendung von hochreinen Metakaolinen (7-10 M-% des Bindemittels) oder Feinstcalcit (5-10 M-% des Bindemittels) allein führte insgesamt zu deutlich geringerer Sulfatbeständigkeit. Hingegen konnten hohe Gehalte an Hüttensand oder Silikastaub auch in Kombination mit Metakaolin und Feinstcalcit den Sulfatwiderstand von Spritzbeton erhöhen. The durability of shotcrete can be degraded by chemical attacks, especially if used as ground support in tunnel construction. In the course of the research project "Advanced and Sustainable Sprayed Concrete (ASSpC)" test specimens of dry-mix and wet-mix shotcrete were sprayed in large-scale tests. The sulfate resistance and the leaching behaviour of these shotcretes were assessed in sulfate-bearing solutions. A test procedure based on the use of shotcrete powders shows that hydrated cement phases dissolve in favour of calcite and ettringite neo-formation. The sulfate expansion measured on drill cores in the second procedure corresponds to the behaviour of the powders, especially regarding the reactivity of calcium-and aluminium-bearing hydrated phases. The resistance against thaumasite attack, assessed by measuring the mass loss of prisms, coincides with the former test results. The exclusive use of high-purity metakaolin (7-10 wt-% of binder) or fine calcium carbonate (5-10 wt-% of binder) leads to a decrease in the sulfate durability. However, high amounts of blast furnace slag or silica fume can increase the sulfate resistance of shotcrete even when used in combination with metakaolin or fine calcium carbonate. Y1 - 2021 UR - https://www.spritzbeton-tagung.com/downloads/vortraege/2021/17_Steindl.pdf SP - 94 EP - 111 ER - TY - CHAP A1 - Galan, Isabel A1 - Thumann, Maria A1 - Briendl, Lukas G. A1 - Röck, Rudolf A1 - Steindl, Florian A1 - Juhart, Joachim A1 - Mittermayr, Florian A1 - Kusterle, Wolfgang ED - Beck, Thomas ED - Myren, Synnøve A. ED - Engen, Siri T1 - From Lab Scale Spraying to Real Scale Shotcreting and back to the Lab T2 - 8th International Symposium on Sprayed Concrete : Modern Use of Wet Mix Sprayed Concrete for Underground Support - Trondheim, Norwegen. - 11. - 14.06.2018 N2 - Before new mixes are sprayed in real scale applications, lab experiments have to be carried out to provide a basis for predicting a good performance in real scale. In many cases, to understand the correlations between the behavior in the lab and in real scale spraying, a further set of experiments after the real spraying is required. In this paper we present such a two way process for two new wet mixes, one with a very low tricalcium aluminate Portland cement and the other one with a CEM I with addition of ultra-fine calcite. Calorimetry and Shear-Modulus measurements were used in the lab to monitor hydration evolution. In the real scale spraying compressive strength was measured at periodic intervals up to 24 hours. The hydration of the sprayed samples was stopped at 3, 6 and 24 hours and samples were scanned with X-ray for the identification and quantification of the phases present. The results presented are used to discuss the extent to which lab experiments can predict the behavior of mixes in real scale and how small changes in the raw materials and the mixes can lead to quite different results. Y1 - 2018 UR - https://betong.net/wp-content/uploads/8th-Sprayed-Concrete_Web-Proceedings.pdf SN - 978-82-8208-060-6 SP - 139 EP - 153 ER -