TY - CHAP A1 - Galan Garcia, Isabel A1 - Stauffacher, Anina A1 - Mittermayr, Florian A1 - Thumann, Maria A1 - Kusterle, Wolfgang A1 - Juilland, Patrick A1 - Stenger, Christian A1 - Lindlar, Benedikt T1 - Estudio de las reacciones de hidratación temprana en el hormigón proyectado T2 - HAC2018 - V Congreso Iberoamericano de Hormigón Autocompactable y Hormigones Especiales ; Valencia 05.03.2018 - 06.03.2018 N2 - El hormigón proyectado es un tipo de hormigón especial utilizado como soporte de rocas durante la construcción de túneles y excavación de minas, entre otras aplicaciones. Las principales características de este tipo de hormigón son el fraguado rápido y el desarrollo de una muy alta resistencia mecánica a edades tempranas, lo cual permite que el hormigón se fije a la base sin necesidad de un soporte extra, endureciéndose en pocos minutos. Las reacciones de hidratación que ocurren en las primeras horas en el hormigón proyectado determinan el desarrollo de las propiedades mecánicas y su estudio es de crucial importancia para entender y optimizar el comportamiento de este tipo de hormigones. El estudio de estas reacciones, sin embargo, resulta relativamente complicado por varias razones: (i) el hormigón proyectado endurece muy rápido, lo cual dificulta su manejo durante los ensayos experimentales, y (ii) composiciones similares mezcladas en el laboratorio no se comportan de forma similar a las proyectadas. En este trabajo se presenta una metodología experimental desarrollada para el estudio de las reacciones de hidratación que ocurren en el hormigón proyectado durante las primeras horas y su correlación con la resistencia mecánica. Y1 - 2018 SN - 9788490485910 U6 - https://doi.org/10.4995/hac2018.2018.6907 PB - Universitat Politècnica València 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 - TY - CHAP A1 - Stauffacher, Anina A1 - Galan, Isabel A1 - Juilland, Patrick A1 - Thumann, Maria A1 - Stenger, Christian A1 - Baldermann, Andre A1 - Mittermayr, Florian A1 - Lindlar, Benedikt A1 - Kusterle, Wolfgang ED - Kusterle, Wolfgang T1 - Einfluss von Hüttensand und ultrafeinem Kalksteinmehl auf die Hydratation von jungem Spritzbeton T2 - Spritzbeton-Tagung 2018, Alpbach, Tirol, 11. und 12. Januar 2018. Tagungsbeiträge. CD-ROM KW - Spritzbeton KW - Feuchtigkeit KW - Hydratation Y1 - 2018 CY - Oberperfuss ER - TY - JOUR A1 - Steindl, Florian R. A1 - Mittermayr, Florian A1 - Sakoparnig, Marlene A1 - Juhart, Joachim A1 - Briendl, Lukas G. A1 - Lindlar, Benedikt A1 - Ukrainczyk, Neven A1 - Dietzel, Martin A1 - Kusterle, Wolfgang A1 - Galan, Isabel T1 - On the porosity of low-clinker shotcrete and accelerated pastes JF - Construction and Building Materials N2 - Although the number and size of interconnected pores have been identified as the most important aspects of concrete microstructure, comprehensive datasets on shotcrete porosity and pore size distributions are still scarce and their key controls are poorly investigated. In this study we investigate the effects of the spraying process, setting accelerator addition and mix design on the microstructure of real-scale dry- and wet-mix shotcrete and hand-mixed and sprayed accelerated pastes. A newly proposed deconvolution analysis of the pore size distributions, measured by mercury intrusion porosimetry, offers increased precision in determining the critical and median pore diameter parameters. In total >50 samples were analysed. Results show that the dry-mix shotcrete exhibits a shift towards coarser pore sizes (∼100–1 μm) than wet-mix shotcrete. Combinations of different supplementary cementitious materials are favourable for producing wet-mix shotcretes with refined pore structures. The addition of setting accelerators, up to 10 wt-% of binder mass, and the spraying process cause systematic variations in the pore volume and pore structure of (sprayed) paste and shotcrete. KW - Porosity KW - Shotcrete KW - Mercury Intrusion KW - Durability KW - SCMs Y1 - 2023 U6 - https://doi.org/10.1016/j.conbuildmat.2023.130461 SN - 0950-0618 VL - 368 PB - Elsevier CY - 14 ER - TY - CHAP A1 - Thumann, Maria A1 - Juhart, Joachim A1 - Röck, Rudolf A1 - Saxer, Andreas A1 - Galan, Isabel A1 - Mittermayr, Florian A1 - Kusterle, Wolfgang T1 - Entwicklung neuer, dauerhafter und nachhaltiger Spritzbetone T2 - Kolloquium Forschung & Entwicklung für Zement und Beton 2018 Y1 - 2018 UR - https://zement.at/downloads/downloads_2018/Kolloquium_Kurzbeitraege_2018_neu.pdf SP - 65 EP - 69 ER -