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Durability of Portland Cement Blends Including Calcined Clay and Limestone: Interactions with Sulfate, Chloride and Carbonate Ions

  • Zhenguo ShiEmail author
  • Mette R. Geiker
  • Klaartje De Weerdt
  • Barbara Lothenbach
  • Josef Kaufmann
  • Wolfgang Kunther
  • Sergio Ferreiro
  • Duncan Herfort
  • Jørgen Skibsted
Conference paper
Part of the RILEM Bookseries book series (RILEM, volume 10)

Abstract

The durability has been investigated for mortars made from a pure Portland cement (CEM I) and five Portland cement – SCM blends, using a cement replacement level of 35 wt% and the following SCM’s: (i) pure limestone, (ii) pure metakaolin, (iii) metakaolin and limestone (3:1 w/w), (iv) metakaolin and silica fume, and (v) metakaolin, silica fume and limestone. The blends with metakaolin and silica fume employ a fixed ratio for these components which mimics the alumina-silicate composition of a 2:1 clay (i.e., montmorillonite). All mortars were demoulded after hydration for one day and cured saturated in water at 20 °C for 90 days prior to exposure. Expansions induced by sulfate attack, chloride profiles, and carbonation depths were measured to investigate the durability performances of the mortars. Porosity and pore connectivity were analysed before exposure by mercury intrusion porosimetry. The results show that mortars incorporating metakaolin, independent of additional silica fume or limestone, all exhibit very high resistance towards sulfate attack and chloride ingress, but are vulnerable to carbonation. The binary Portland cement – limestone blend is most susceptible to all types of studied chemical attacks, as expected. The pure Portland cement exhibits poor resistance to sulfate attack and chloride ingress, but high resistance to carbonation. The observed performances for the different blends can be explained based on their microstructure and phase assemblages. For example, the presence of metakaolin increases the chloride-ion binding capacity and enhances chloride resistance by the low pore connectivity present in the hydrated blends with metakaolin.

Keywords

Portland Cement Silica Fume Mercury Intrusion Porosimetry Sulfate Attack Pore Connectivity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Notes

Acknowledgments

The Danish Council for Strategic Research is acknowledged for financial support to the LowE-CEM project.

References

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Copyright information

© RILEM 2015

Authors and Affiliations

  • Zhenguo Shi
    • 1
    Email author
  • Mette R. Geiker
    • 2
  • Klaartje De Weerdt
    • 3
  • Barbara Lothenbach
    • 4
  • Josef Kaufmann
    • 4
  • Wolfgang Kunther
    • 1
  • Sergio Ferreiro
    • 5
  • Duncan Herfort
    • 5
  • Jørgen Skibsted
    • 1
  1. 1.Department of Chemistry and Interdisciplinary Nanoscience, Center (iNANO)Aarhus UniversityAarhus CDenmark
  2. 2.Department of Structural EngineeringNorwegian University of Science and TechnologyTrondheimNorway
  3. 3.SINTEF Building and InfrastructureTrondheimNorway
  4. 4.Laboratory for Concrete and Construction ChemistryEmpaDübendorfSwitzerland
  5. 5.Cementir Holding S.p.AAalborg Portland A/SAalborgDenmark

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