Thermodynamic modelling of phase evolution in alkali-activated slag cements exposed to carbon dioxide

Xinyuan Ke, Susan A. Bernal, John L. Provis, Barbara Lothenbach

Research output: Contribution to journalArticlepeer-review

Abstract

Carbonation of cementitious materials induced by their interaction with atmospheric CO2 is one of the main degradation mechanisms threatening their durability. In this study, a novel thermodynamic model to predict the phase evolution of alkali-activated slags exposed to an accelerated carbonation environment is presented. This model predicts the phase assemblages of carbonated alkali-activated slag cements, as a function of CO2 uptake under 1 v/v % CO2 conditions, considering the bulk slag chemistry and activators used. The changes taking place during the carbonation process regarding the physicochemical properties of the main binding gel, an alkali calcium aluminosilicate hydrate (C-(N)-A-S-H), the secondary reaction products Ca[sbnd]Al and Mg[sbnd]Al layered double hydroxides, and amorphous aluminosilicate gels, were simulated and discussed. The predictions of the thermodynamic model are in good agreement with experimental data retrieved from the literature, demonstrating that this is a valuable tool for predicting long-term performance of alkali-activated slag cements.

Original languageEnglish
Article number106158
JournalCement and Concrete Research
Volume136
Early online date21 Jun 2020
DOIs
Publication statusPublished - 1 Oct 2020

Keywords

  • (A) Reaction
  • (B) Thermodynamic calculations
  • (C) Carbonation
  • (D) Alkali-activated cement

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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