Carbonation degree evaluation of recycled aggregate concrete using carbonation zone widths

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Original languageEnglish
Article number101366
Journal / PublicationJournal of CO2 Utilization
Online published11 Nov 2020
Publication statusPublished - Jan 2021


Evaluating the carbonation degree of concrete using the carbonation zone width provides more accurate results than using the carbonation depth determined via pH indicators. In this study, a testing and calculation method for the carbonation zone widths of recycled aggregate concrete (RAC) was developed. The method was applied after the old mixed mortar (OMM) and new mixed mortar (NMM) were distinguished using iron oxide. The effects of the type and replacement ratio of the recycled coarse aggregate, carbonation period, and sampling location on the carbonation zone widths of the RAC were investigated. Furthermore, the mathematical relationships between the carbonation depths and carbonation zone widths were analysed. The results indicated that the carbonation zone widths were significantly larger than the carbonation depths. Additionally, using samples of OMM and NMM yielded significantly different results. Therefore, selecting a larger carbonation zone width can avoid overestimation of the carbonation service life of concrete structures. Furthermore, polynomial and logarithmic functions were suggested for the calculations of the carbonation zone widths when selecting NMM and OMM samples, respectively. This study is useful for engineers because the findings can assist in evaluating the carbonation degree of concrete and the carbonation service life of structures according to the carbonation depth.

Research Area(s)

  • Carbonation depth, Carbonation zone width, Mortar inhomogeneity, New mixed mortar and old mixed mortar, Recycled aggregate concrete