Surfactant-assisted purification of an impure kaolinite clay to improve its pozzolanic reactivity in concrete

Supplementary cementitious materials (SCMs) are beneficial for improving concrete’s long-term performance, durability, and environmental impact. Impure clay sources are abundant and when calcined, may serve as suitable SCMs. This study presents and evaluates a method for enrichment of low-purity kaolinite clays to improve their reactivity and performance in concrete. A byproduct clay containing 27% kaolinite, 10% muscovite, and 52% quartz was obtained by drying aggregate wash water slurry from a commercial sand and gravel pit. Several methods were evaluated for separating the clay and non-clay minerals. Among others, dispersant-assisted sedimentation, using 50 0.06% sodium hexametaphosphate, was shown to be effective in enriching the clay content which, upon calcination, produced a purified calcined clay (PCC) containing 64% metakaolinite, 26% muscovite, and 2% quartz. Both the PCC and the non-purified calcined clay (CC) were evaluated for their physical and chemical properties, compliance with ASTM C618, pozzolanic reactivity, and their performance in mortar and concrete mixtures. The results show both SCMs to be valuable while PCC is clearly a higher performance pozzolan.

This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://doi.org/10.1061/(ASCE)MT.1943-5533.0004216

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Work Title Surfactant-assisted purification of an impure kaolinite clay to improve its pozzolanic reactivity in concrete
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Open Access
Creators
  1. Khashayar Jafari
  2. Jinyoung Yoon
  3. Raikhan Tokpatayeva
  4. Jan Olek
  5. Farshad Rajabipour
Keyword
  1. Calcined clay
  2. Pozzolan
  3. Purification
  4. Recycling
  5. Concrete performance
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Journal of Materials in Civil Engineering
Publication Date March 21, 2022
Publisher Identifier (DOI)
  1. https://doi.org/10.1061/(ASCE)MT.1943-5533.0004216
Deposited July 12, 2023

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Version 1
published

  • Created
  • Added Surfactant_assisted.pdf
  • Added Creator Khashayar Jafari
  • Added Creator Jinyoung Yoon
  • Added Creator Raikhan Tokpatayeva
  • Added Creator Jan Olek
  • Added Creator Farshad Rajabipour
  • Published
  • Updated Keyword, Publisher, Publication Date Show Changes
    Keyword
    • Calcined clay, Pozzolan, Purification, Recycling, Concrete performance
    Publisher
    • ASCE Journal of Materials in Civil Engineering
    • Journal of Materials in Civil Engineering
    Publication Date
    • 2022-06-01
    • 2022-03-21
  • Updated