Characterization and quantification of the pozzolanic reactivity of natural and non-conventional pozzolans

High quality pozzolans are needed to produce durable and low CO2 concrete. While extensive literature is available on pozzolanic reactivity and reaction products of conventional fly ash and slag cement, similar information is scarce for natural and non-conventional pozzolans (NNPs), impeding their use in concrete. This study presents a comprehensive evaluation of eleven NNPs, including calcined clays, volcanic ashes, ground bottom ashes, and fluidized bed combustion (FBC) fly ashes. The chemistry, mineralogy, physical properties, and pozzolanic reactivity of these materials were evaluated and benchmarked against conventional pozzolans. Except for one case of high SO3, all NNPs met ASTM C618 specifications as well as RILEM limits of pozzolanic reactivity. Based on ASTM C1897 (the R3 test), calcined clays were found to be significantly more reactive than fly ash and comparable with slag and silica fume. Volcanic ashes and FBC fly ashes showed similar pozzolanic reactivity to that of Class F fly ash, while ground bottom ashes were comparable with the top 50% of Class F fly ashes. The reaction products of these NNPs were identified using QXRD and thermodynamic modeling as C-A-S-H, mono- and hemi-carboaluminate, monosulfate, and ettringite. Calcined clays formed monosulfate and little to no ettringite while other NNPs formed ettringite but no monosulfate. This was attributed to the availability and dissolution kinetics of alumina versus calcite in the R3 experiment.

© This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

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Work Title Characterization and quantification of the pozzolanic reactivity of natural and non-conventional pozzolans
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Open Access
Creators
  1. Jinyoung Yoon
  2. Khashayar Jafari
  3. Raikhan Tokpatayeva
  4. Sulapha Peethamparan
  5. Jan Olek
  6. Farshad Rajabipour
Keyword
  1. Pozzolanic reactivity
  2. Reaction products
  3. Calcined clay
  4. Volcanic ash
  5. Ground 36 bottom ash
  6. FBC fly ash
License CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives)
Work Type Article
Publisher
  1. Cement and Concrete Composites
Publication Date August 20, 2022
Publisher Identifier (DOI)
  1. https://doi.org/10.1016/j.cemconcomp.2022.104708
Deposited July 12, 2023

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Version 1
published

  • Created
  • Added Characterizing_and_quantifying.pdf
  • Added Creator Jinyoung Yoon
  • Added Creator Khashayar Jafari
  • Added Creator Raikhan Tokpatayeva
  • Added Creator Sulapha Peethamparan
  • Added Creator Jan Olek
  • Added Creator Farshad Rajabipour
  • Published
  • Updated Keyword, Publication Date Show Changes
    Keyword
    • Pozzolanic reactivity, Reaction products, Calcined clay, Volcanic ash, Ground 36 bottom ash, FBC fly ash
    Publication Date
    • 2022-10-01
    • 2022-08-20
  • Updated