Supercritical carbonation of calcareous composites: influence of curing

Elham Farahi, Phil Purnell*, Neil R. Short

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This paper reports the effect of curing on the susceptibility of cementitious composites to carbonation using supercritical carbon dioxide. Samples made using a compression moulding technique were cured in water before and/or after carbonation and the effect on porosity, microstructure, solid phase assemblage and flexural strength was determined. In terms of development of mechanical strength, no benefit was gained from any period of pre- or post-carbonation curing regime. Yet samples cured prior to carbonation underwent minimal chemical reaction between supercritical carbon dioxide and calcium hydroxide, unhydrated cement or C-S-H. Thus there was no correlation between chemical degree of reaction and strength development. The effects responsible for the marked strength gain in supercritically carbonated samples must involve subtle changes in the microstructure of the C-S-H gel, not simple pore filling by calcium carbonate as is often postulated.

Original languageEnglish
Pages (from-to)48-53
Number of pages6
JournalCement and Concrete Composites
Volume43
Early online date25 Mar 2013
DOIs
Publication statusPublished - Oct 2013

Keywords

  • cement
  • curing
  • flexural testing
  • lime
  • mechanical processing
  • petrography
  • super-critical carbonation

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