Selection and characterisation of geological materials for use as geopolymer precursors

Abstract

Geopolymer binders are generally formed by reacting powdered aluminosilicate precursors with alkali silicate activators. Most research to date has concentrated on using either pulverised fuel ash or high purity dehydroxylated kaolin (metakaolin) in association with ground granulated blast furnace slag as the main precursor material. However, recently, attention has turned to alternative calcined clays that are abundant throughout the globe and have lower kaolinite contents than commercially available metakaolins. Due to the lack of clear and simple screening protocols enabling assessment of such geological resources for use as precursors in geopolymer systems, the present paper presents results from experimental work that was carried out to develop a functional binder using materials containing kaolinite taken from the Interbasaltic Formation of Northern Ireland. The influence of mineralogy has been examined, and a screening process, using three Interbasaltic materials as examples, that will assist in the rapid selection of suitable geopolymeric precursors from such materials is outlined.

Keywords:

• Geopolymer
• Kaolinitic clay
• Interbasaltic Formation
• Screening

Acknowledgements

The authors would like to thank Invest NI and the KTP scheme for funding part of the research in the present paper and also the University of Leicester for carrying out XRF analyses. The authors also thank Mr J. Blackstock and banah UK Ltd for their support of the research in the present paper.