Dry Ice–Driven Mechanochemical Carbonation of Recycled Concrete Fines for Enhanced Recycling and Carbon Capture

Baki V. A.

Conference Safe, Sustainable and Swift Reconstruction of Ukraine, Lviv, Ukrayna, 19 - 20 Mart 2026, cilt.1, sa.1, ss.1, (Özet Bildiri)

  • Yayın Türü: Bildiri / Özet Bildiri
  • Cilt numarası: 1
  • Basıldığı Şehir: Lviv
  • Basıldığı Ülke: Ukrayna
  • Sayfa Sayıları: ss.1
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

Dry Ice–Driven Mechanochemical Carbonation of Recycled Concrete Fines for Enhanced Recycling and Carbon Capture

V.A.Baki1

1Faculty of Engineering, Department of Civil Engineering, Karadeniz Technical University, Trabzon, Turkiye

Abstract

The low carbonation efficiency of traditional wet and dry carbonation methods limits the industrial utilisation of recycled concrete fines (RCF). In this study, a novel mechanochemical carbonation (MC) technique employing dry ice as the CO₂ source is introduced. The carbonation kinetics, phase evolution, and microstructural development of RCF throughout the MC process are comprehensively examined, and the pozzolanic properties of the carbonated RCF are evaluated using the R3 test method. The findings revealed a significant improvement in carbonation efficiency and CO₂ utilization, with a high degree of carbonation achieved in only 10 minutes. This performance surpassed the levels typically reported in the literature, where similar results require about 2 hours of wet carbonation or even 24 hours of dry carbonation. The MC process achieved a CO₂ uptake greater than 0.3 g-CO₂/g-RCF. This enhanced performance was driven by mechanochemical effects, which improved the particle geometry, removed passivating surface layers, and increased CO₂ dissolution. These combined effects promoted the structural breakdown of the RCF and accelerated the carbonation reaction.

A further unique outcome of MC treatment was the formation of a larger proportion of metastable calcium carbonate phases with smaller crystallite sizes, resulting from the modified carbonation conditions and the structural changes induced by mechanochemical activation. Additionally, the formation of silica gels during MC carbonation significantly improved the pozzolanic reactivity of RCF, leading to at least a twofold increase as indicated by the R3 bound-water test.