Characterisation of magnesium potassium phosphate cements blended with fly ash and ground granulated blast furnace slag

Laura J. Gardner, Susan A. Bernal, Samuel A. Walling, Claire L. Corkhill, John L. Provis, Neil C. Hyatt*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

254 Citations (Scopus)

Abstract

Magnesium potassium phosphate cements (MKPCs), blended with 50 wt.% fly ash (FA) or ground granulated blast furnace slag (GBFS) to reduce heat evolution, water demand and cost, were assessed using compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy on 25Mg, 27Al, 29Si, 31P and 39K nuclei. We present the first definitive evidence that dissolution of the glassy aluminosilicate phases of both FA and GBFS occurred under the pH conditions of MKPC. In addition to the main binder phase, struvite-K, an amorphous orthophosphate phase was detected in FA/MKPC and GBFS/MKPC systems. It was postulated that an aluminium phosphate phase was formed, however, no significant Al-O-P interactions were identified. High-field NMR analysis of the GBFS/MKPC system indicated the potential formation of a potassium-aluminosilicate phase. This study demonstrates the need for further research on these binders, as both FA and GBFS are generally regarded as inert fillers within MKPC.

Original languageEnglish
Pages (from-to)78-87
Number of pages10
JournalCement and Concrete Research
Volume74
DOIs
Publication statusPublished - 1 Aug 2015

Bibliographical note

Publisher Copyright:
© 2015 The Authors. Published by Elsevier Ltd.

Keywords

  • Chemically Bonded Ceramics (D)
  • Fly ash (D)
  • Granulated blast furnace slag (D)
  • Microstructure (B)
  • SEM (B)

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