Articles
  • Geopolymerisation of un-calcined kaolin by the novel heat curing method

  • Selin Demir and Süleyman Yaşın*

  • Karabük University, Department of Metallurgy and Materials Engineering, 78050, Karabük, Turkey

  • This article is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In this study, heat curing technique (up to 320 oC) that allows the usage of sodium silicate solutions with un-calcined kaolins to offer a durable geopolymeric binder in a short time was investigated. Samples containing up to 40 wt.% binder have been produced to observe the binder behaviour over a wide range of additions by heat curing for one hour. The cured samples consist of kaolinite and amorphous phase and crystallinity was decreased with increasing curing temperatures. 240 oC was the threshold temperature for the strength development of the samples. Condensation reactions between Al-OH- units in un-calcined kaolin and silanol groups in sodium silicate solution that yield sialate (Si-O-Al-O) bridges detected by infrared analyses are the considered mechanisms of promoter effects of kaolinite. Optimum compressive strength (23.4 MPa.) was obtained with the samples produced with 20 wt.% binder addition and 300 oC curing temperature


Keywords: Kaolinite, Geopolymer, Sodium silicate, Heat curing

This Article

  • 2022; 23(1): 41-47

    Published on Feb 28, 2022

  • 10.36410/jcpr.2022.23.1.41
  • Received on Aug 5, 2021
  • Revised on Nov 9, 2021
  • Accepted on Nov 27, 2021

Correspondence to

  • Süleyman Yaşın

  • Karabük University, Department of Metallurgy and Materials Engineering, 78050, Karabük, Turkey
    Tel : +90 444 04 78

  • E-mail: syasin@karabuk.edu.tr