On the porosity of low-clinker shotcrete and accelerated pastes

Florian R. Steindl*, Florian Mittermayr, Marlene Sakoparnig, Joachim Juhart, Lukas Briendl, Benedikt Lindlar, Neven Ukrainczyk, Martin Dietzel, Wolfgang Kusterle, Isabel Galan

*Korrespondierende/r Autor/-in für diese Arbeit

Publikation: Beitrag in einer FachzeitschriftArtikelBegutachtung

Abstract

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.

Originalspracheenglisch
Aufsatznummer130461
FachzeitschriftConstruction and Building Materials
Jahrgang368
DOIs
PublikationsstatusVeröffentlicht - 3 März 2023

ASJC Scopus subject areas

  • Tief- und Ingenieurbau
  • Bauwesen
  • Allgemeine Materialwissenschaften

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