Comparison of lithomarge and cement-based mortars performance in aggressive aqueous environments

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Abstract

The resistance of room temperature cured geopolymer mortar (GPM) against chemical attacks, i.e. sodium and magnesium sulfate solutions, and sulfuric and hydrochloric acid solutions, was evaluated. GPM was formulated using a lithomarge precursor (low-purity kaolin) to achieve 28-day characteristic compressive strength of 60 MPa. Its performance was compared with an equivalent Portland cement mortar (PCM) having the same paste volume and strength grade. 28-day old bar samples were stored in 0.352 mol/L sulfate solutions for 52 weeks whereas 28-day old cube samples were exposed for 8 weeks to acid solutions with concentration of 0.52 mol/L. GPM showed superior performance against sulfate attack when compared to PCM. No visual deterioration was observed in GPM, the length changes were relatively small, and no changes to the microstructure were detected – in contrast to severely deteriorated PCM. As confirmed by visual observations and lower mass loss, GPM showed better resistance to attack by both acids than PCM. GPM provided a better quality (lower permeability) of an acid-degraded layer, lowering the degree of further deterioration. The main mechanisms of the matrix deterioration of GPM in both acids was dealumination of the hardened binder, with a higher degree of changes detected for sulfuric acid.
Original languageEnglish
Number of pages10
Publication statusPublished - 2018
EventSixth International Conference on the Durability of Concrete Structures - University of Leeds , Leeds, United Kingdom
Duration: 18 Jul 201820 Jul 2018
https://engineering.leeds.ac.uk/info/201479/conferences/270/sixth_international_conference_on_durability_of_concrete_structures_icdcs2018

Conference

ConferenceSixth International Conference on the Durability of Concrete Structures
Abbreviated titleICDCS2018
CountryUnited Kingdom
CityLeeds
Period18/07/201820/07/2018
Internet address

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Keywords

  • Lithomarge
  • Geopolymer mortars
  • Portland cement mortars
  • Sulfate attack
  • Acid attack

Cite this

Kwasny, J., Aiken, T., Soutsos, M., Cleland, D., & McIntosh, A. (2018). Comparison of lithomarge and cement-based mortars performance in aggressive aqueous environments. Paper presented at Sixth International Conference on the Durability of Concrete Structures, Leeds, United Kingdom.