@inproceedings{StauffacherGalanJuillandetal., author = {Stauffacher, Anina and Galan, Isabel and Juilland, Patrick and Thumann, Maria and Stenger, Christian and Baldermann, Andre and Mittermayr, Florian and Lindlar, Benedikt and Kusterle, Wolfgang}, title = {Einfluss von H{\"u}ttensand und ultrafeinem Kalksteinmehl auf die Hydratation von jungem Spritzbeton}, series = {Spritzbeton-Tagung 2018, Alpbach, Tirol, 11. und 12. Januar 2018. Tagungsbeitr{\"a}ge. CD-ROM}, booktitle = {Spritzbeton-Tagung 2018, Alpbach, Tirol, 11. und 12. Januar 2018. Tagungsbeitr{\"a}ge. CD-ROM}, editor = {Kusterle, Wolfgang}, address = {Oberperfuss}, subject = {Spritzbeton}, language = {de} } @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{SakoparnigBaldermannThumannetal., author = {Sakoparnig, Marlene and Baldermann, Andre and Thumann, Maria and Mittermayr, Florian and Kusterle, Wolfgang}, title = {Bestimmung der experimentellen Calcium-Auslaugung an Spritzbetonbohrkernen: Methodenvergleich und Update}, series = {Spritzbeton-Tagung 2018, Alpbach, {\"O}sterreich 11.-12.01.2018}, booktitle = {Spritzbeton-Tagung 2018, Alpbach, {\"O}sterreich 11.-12.01.2018}, abstract = {Im Rahmen des FFG-Forschungsprojektes „Entwicklung neuer dauerhafter und nachhaltiger Spritzbetone (Advanced and sustainable sprayed concrete; ASSpC)" werden Methoden zur Pr{\"u}fung der Calcium-Auslaugung von Spritzbeton eingesetzt bzw. weiterentwickelt. Bestimmt wurde daf{\"u}r das Reduzierte Versinterungspotential nach Regelwerken der {\"O}sterreichischen Bautechnik Vereinigung und das Auslaugverhalten von Spritzbeton bei leichtem S{\"a}ureangriff (Salpeters{\"a}ure und Kohlens{\"a}ure), um dauerhaftigkeitsrelevante Parameter im Bereich der Wechselwirkungen von Spritzbeton mit leicht sauren (Kohlens{\"a}ure- und Nitrathaltigen) Oberfl{\"a}chen-, Grund- und Sickerw{\"a}ssern zu untersuchen und potentielle Sch{\"a}digungsmechanismen zu identifizieren und zu quantifizieren. Die Vor- und Nachteile der verwendeten Pr{\"u}fmethoden zum l{\"o}senden Angriff werden in Bezug auf die Dauerhaftigkeit von Spritzbeton diskutiert.}, language = {de} } @inproceedings{SteindlMittermayrThumannetal., author = {Steindl, F. and Mittermayr, F. and Thumann, Maria and Juhart, J. and Galan Garcia, Isabel and Baldermann, Andre and Briendl, Lukas G. and Sakoparnig, M. 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} } @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{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{ThumannBriendlJuhartetal., author = {Thumann, Maria and Briendl, Lukas G. and Juhart, J. 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{JuhartBriendlRoecketal., author = {Juhart, J. and Briendl, Lukas G. and R{\"o}ck, Rudolf and Galan, Isabel and Thumann, Maria and Mittermayr, F. 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} } @inproceedings{GalanThumannBriendletal.2018, author = {Galan, Isabel and Thumann, Maria and Briendl, Lukas G. and R{\"o}ck, Rudolf and Steindl, Florian and Juhart, Joachim and Mittermayr, Florian and Kusterle, Wolfgang}, title = {From Lab Scale Spraying to Real Scale Shotcreting and back to the Lab}, series = {8th International Symposium on Sprayed Concrete : Modern Use of Wet Mix Sprayed Concrete for Underground Support - Trondheim, Norwegen. - 11. - 14.06.2018}, booktitle = {8th International Symposium on Sprayed Concrete : Modern Use of Wet Mix Sprayed Concrete for Underground Support - Trondheim, Norwegen. - 11. - 14.06.2018}, editor = {Beck, Thomas and Myren, Synn{\o}ve A. and Engen, Siri}, isbn = {978-82-8208-060-6}, pages = {139 -- 153}, year = {2018}, abstract = {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.}, language = {en} } @inproceedings{JuhartBriendlMittermayretal., author = {Juhart, Joachim and Briendl, Lukas G. and Mittermayr, Florian and Thumann, Maria and R{\"o}ck, Rudolf and Kusterle, Wolfgang}, title = {Optimierte Eigenschaften von Spritzbeton durch kombinierte Zusatzstoffe}, series = {Tagungs-CD der Spritzbeton-Tagung 2018, 11.-12. Januar 2018, Alpbach, Tirol, CD-ROM}, booktitle = {Tagungs-CD der Spritzbeton-Tagung 2018, 11.-12. Januar 2018, Alpbach, Tirol, CD-ROM}, 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} } @inproceedings{JuhartBriendlMittermayretal., author = {Juhart, J. and Briendl, Lukas G. and Mittermayr, F. and R{\"o}ck, R. and Thumann, Maria and Kusterle, Wolfgang}, title = {Mischungsentwicklung von nachhaltigem Spritzbeton mit kombinierten Zusatzstoffen}, series = {Beton Graz '18 : 4. Grazer Betonkolloquium : 20./21. September 2018}, booktitle = {Beton Graz '18 : 4. Grazer Betonkolloquium : 20./21. September 2018}, publisher = {Verlag der Technischen Universit{\"a}t Graz}, address = {Graz}, isbn = {978-3-85125-621-5}, pages = {139 -- 152}, abstract = {Spritzbeton ist nachhaltig, wenn er sowohl umweltfreundlich als auch dauerhaft ist. Traditionelle Mischungszusammensetzungen f{\"u}r Spritzbeton enthalten einen hohen Anteil an fein gemahlenem Portlandzement und an Erstarrungsbeschleunigern. Beide Komponenten sind f{\"u}r eine sehr schnelle Festigkeitsentwicklung, aber auch hohe Umweltauswirkungen (wie CO2-Emissionen, Prim{\"a}renergiebedarf) verantwortlich. Portlandzement ist ein hervorragendes Bindemittel, bringt aber ein hohes Versinterungspotenzial und bei normaler Zusammensetzung einen geringen Widerstand gegen chemischen Angriff, wie zum Beispiel den Sulfatangriff aus dem Bergwasser, mit sich. Hingegen k{\"o}nnen latent hydraulische und puzzolanische Zusatzstoffe die Dauerhaftigkeit erh{\"o}hen, sind aber auch f{\"u}r eine langsame Festigkeitsentwicklung bekannt. Im Beitrag wird ein neues Konzept des Mischungsentwurfs vorgestellt, das auf der Auswahl geeigneter Zusatzstoffe (i.e. feinste Kalksteinmehle, die die Hydratation beschleunigen, kombiniert mit gemahlenem H{\"u}ttensand und Puzzolanen), der Optimierung von Packungsdichte und Wasserbedarf sowie einem optimalen Mischungsverh{\"a}ltnis aller Feinstoffe beruht. Es wird an exemplarischen Mischungszusammensetzungen gezeigt, welche Eigenschaften bzw. Leistungsmerkmale in Labortests sowie in großmaßst{\"a}blichen Spritzversuchen erreicht werden k{\"o}nnen.}, language = {de} } @article{SteindlGalanBaldermannetal., author = {Steindl, Florian Roman and Galan, Isabel and Baldermann, Andre and Sakoparnig, Marlene and Briendl, Lukas G. and Juhart, Joachim and Thumann, Maria and Dietzel, Martin and R{\"o}ck, Rudolf and Kusterle, Wolfgang and Mittermayr, Florian}, title = {Sulfate durability and leaching behaviour of dry- and wet-mix shotcrete mixes}, series = {Cement and Concrete Research}, volume = {137}, journal = {Cement and Concrete Research}, number = {November}, publisher = {Elsevier}, doi = {10.1016/j.cemconres.2020.106180}, pages = {1 -- 19}, abstract = {Shotcrete is a material frequently used in underground constructions such as tunnels, where Ca leaching and sulfate attack are important durability issues. In this study, two test methods were employed to investigate the sulfate resistance and leaching behaviour of dry- and wet-mix shotcretes in sulfate solutions on a time-resolved basis. Tests on powdered samples showed the dissolution of AFm, portlandite and C-A-S-H, subsequently followed by the precipitation of calcite and ettringite. The extent of sulfate expansion of drill cores corresponded to the chemical response of the powder materials, particularly on the reactivity of Ca- and Al-containing hydrated cement phases. The use of high-purity metakaolin (7-10 wt\%) in the shotcrete binder significantly decreased the sulfate durability, while high amounts of other SCMs such as blast-furnace slag and silica fume (> 20 wt\%) had a positive effect on the durability of shotcrete.}, 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} }