Comparing the reactivity of different natural calcined clays under alkali activa- tion

Author(s): Ahmed Zohair Khalifa, Yiannis Pontikes, Jan Elsen, Özlem Cizer
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 472-472
Total Pages: 1
Language : English

Abstract: Metakaolin is one of the most popular solid aluminosilicate precursors for the synthesis of geopolymers. Despite its high reactivity and availability, there is a noticeable move towards the use of other natural clays as alternative precursors, due to their plentiful supply and widespread availability. Natural clays usually consist of a combination of 1:1 and 2:1 layer silicates. Four various natural clays with different proportions of 1:1 and 2:1 clay minerals were used in this study. The presence of different clay minerals yields a range of Si/Al ratio from 1.2 to 3.4.
This study aims firstly to determine the optimum calcination conditions to activate the clay minerals. Clays were calcined at different temperatures (700 to 900 °C) for different holding times (10 seconds to 60 minutes). The thermal transformations were studied by TGA and XRD analyses. The reactivity of the calcined clays with alkalis was assessed by the dissolution test and isothermal conduction calorimetry. The second aim of this study is to compare the reactivity of the calcined clays under alkali activation using NaOH. The chemical, mineralogical and physical properties of natural and calcined clays were characterized using XRD, calorimetry, ICP-OES, PSD, and BET analyses.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00