Influence of combined carbonation and chloride ingress regimes on rate of ingress and redistribution of chlorides in concretes

Y. Wang, S. Nanukuttan, Y. Bai, P.A.M. Basheer

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)
400 Downloads (Pure)

Abstract

In majority of exposure environments for concrete structures, there is a high probability of the cyclic occurence of both chloride ingress and carbonation. This paper reports a detailed investigation on the influence of carbonation on both the ingress and distribution of chlorides in three different types of concretes, by comparing results from exposure to chlorides, chlorides before carbonation and chlorides after carbonation. Concretes studied were of 0.55 water-binder ratio with 100% Portland Cement (PC), 70% PC + 30% pulverized fuel ash (PFA) and 85% PC + 10% PFA + 5% microsilica (MS) as binders. Chloride profiles were compared to assess the effects of all variables studied in this research. The effect of carbonation was quantified by measuring the consumption of hydroxyl ions (OH−), air permeability and chloride migration coefficient. The results indicated that carbonation of concrete increases chloride transport, but the precise nature of this is dependent on the combined regime as well as the type of binder. In general, it was found that carbonation of chloride contaminated concretes results in a decrease of their chloride binding capacity, that is it releases the bound Cl− in concretes and pushes chlorides inwards, as has been established previously by other researchers. However, it is established in this research that the combined regimes detrimentally affect the service life of concrete structures, particularly when chloride induced corrosion is a concern.
Original languageEnglish
Pages (from-to)173-183
Number of pages11
JournalConstruction and Building Materials
Volume140
Early online date01 Mar 2017
DOIs
Publication statusPublished - 01 Jun 2017

Keywords

  • Air permeability;
  • Carbonation
  • Chloride profile
  • Chloride migration
  • pH profile
  • Combined exposures

ASJC Scopus subject areas

  • Civil and Structural Engineering

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