Uptake of chloride and carbonate by Mg-Al and Ca-Al layered double hydroxides in simulated pore solutions of alkali-activated slag cement

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

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Chloride ingress and carbonation are major causes of degradation of reinforced concrete. To enable prediction of chloride ingress, and thus to improve the durability of structural alkali-activated slag cement (AAS) based concretes, it is necessary to understand the ionic interactions taking place between chlorides, carbonates, and the individual solid phases which comprise AAS. This study focused on two layered double hydroxides (LDH) representing those typically identified as reaction products in AAS: an Mg-Al hydrotalcite-like phase, and an AFm structure (strätlingite), in simulated AAS pore solutions. Surface adsorption and interlayer ion-exchange of chlorides occurred in both LDH phases; however, chloride uptake in hydrotalcite-group structures is governed by surface adsorption, while strätlingite shows the formation of a hydrocalumite-like phase and ion exchange. For both Ca-Al and Mg-Al LDHs, decreased chloride uptakes were observed from solutions with increased [CO3 2−]/[OH] ratios, due to the formation of carbonate-containing hydrotalcite and decomposition of AFm phases, respectively.

Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalCement and Concrete Research
Volume100
Early online date24 May 2017
DOIs
Publication statusPublished - 1 Oct 2017

Keywords

  • Adsorption (C)
  • Alkali-activated cement (D)
  • Chloride (D)
  • Durability (D)
  • Pore solution (B)

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

Cite this

Uptake of chloride and carbonate by Mg-Al and Ca-Al layered double hydroxides in simulated pore solutions of alkali-activated slag cement. / Ke, Xinyuan; Bernal, Susan A.; Provis, John L.

In: Cement and Concrete Research, Vol. 100, 01.10.2017, p. 1-13.

Research output: Contribution to journalArticle

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