A comparison of liquid-solid and gas-solid accelerated carbonation for enhancement of recycled concrete aggregate

Songhui Liu, Peiliang Shen, Dongxing Xuan, Long Li, Adebayo Sojobi, Baojian Zhan, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

18 Citations (Scopus)


To enhance the properties of recycled concrete aggregates (RCA), a liquid-solid carbonation process was developed and compared with the conventional gas-solid pressurized carbonation method. The performance of RCA and the recycled aggregate concrete (RAC) prepared with the carbonated RCA by the two aforementioned carbonation methods was evaluated. The carbonation products assemblage, microstructure and porosity evolution were first characterized. The results indicated that after subjecting to a 10-min liquid-solid carbonation process, a reduction of 12.2% in RCA water absorption and an increase of 2.6% in density were achieved, which were more efficient when compared to the 24-h gas-solid pressurized carbonation. More importantly, the compressive strength of RAC prepared with the 6-h liquid-solid carbonated RCA was significantly improved. In light of microstructural analysis, the enhanced performance of RAC was attributed to more additional mono-carbonate (Mc) and C–S–H gel formed at the interface between the liquid-solid carbonated RCA and the new cement pastes.

Original languageEnglish
Article number103988
JournalCement and Concrete Composites
Publication statusPublished - Apr 2021


  • Gas-solid pressurized carbonation
  • Interface
  • Liquid-solid carbonation
  • Recycled aggregate concrete
  • Recycled concrete aggregate

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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