Durability of clinker reduced shotcrete: Ca2+ leaching, sintering, carbonation & chloride penetration: Ca2+ leaching, sintering, carbonation and chloride penetration

Marlene Sakoparnig*, Isabel Galan, Florian R. Steindl, Wolfgang Kusterle, Joachim Juhart, Cyrill Grengg, Lukas Briendl, Andreas Saxer, Maria Thumann, Florian Mittermayr

*Corresponding author for this work

Research output: Contribution to journalArticle

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.

Original languageEnglish
Article number78
JournalMaterials and Structures
Volume54
Issue number2
DOIs
Publication statusPublished - Apr 2021

Keywords

  • Carbonate precipitation
  • Carbonation
  • Chloride penetration
  • Durability
  • Leaching
  • Shotcrete

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)
  • Mechanics of Materials

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