Carbonation of the synthetic calcium silicate hydrate (C-S-H) under different concentrations of CO2: Chemical phases analysis and kinetics
Journal article, 2020

In this study, the chemical phases analysis and the kinetics of synthetic calcium silicate hydrate (C-S-H) under differentCO2concentrations (natural (0.03%), 3%, 10%, 20%, 50%, 100%) were investigated. For this aim, the scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed for microstructure characterisation. The 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) coupled with mass spectrometer (MS) were used for characterising the chemical phases before and after carbonation. From the NMR results, it was found that C-S-H would be partly decalcified under the natural condition but completely under the accelerated conditions. Two equations related to the carbonation kinetics under natural and accelerated conditions were proposed respectively. The compositions in decalcified C-S-H were not affected by the CO2 concentration. The XRD analysis showed that vaterite, aragonite and calcite were coexistent after carbonation, which would be transformed to aragonite and calcite with further carbonation. The preferential formation of the allotropic calcium carbonate was not impacted by the concentration of CO2 either. Based on the TGA-MS test, the stoichiometric formula of synthetic C-S-H was determined with CaOâ'™SiO2â'™0.87H2O or Câ Sâ H0.87. In addition, a carbonation kinetics model was proposed to learn the carbonation kinetics of C-S-H carbonated in different CO2 concentrations. The experimental data fitted well with the model. The carbonation kinetics between 3% and 20% CO2 are similar, but different from that under 50% and 100% CO2

Chemical phases

Kinetics

Different CO concentration 2

Carbonation

Synthetic C-S-H

Author

[Person 27925e4f-7243-4143-afa4-577dbfbce764 not found]

China Earthquake Administration

Shenzhen University

[Person 15a8570c-b611-4cd4-9078-94ba59de940d not found]

Shenzhen University

[Person 6f059837-9a64-4bf3-af1e-80897b825396 not found]

China Earthquake Administration

Shenzhen University

[Person 303f8a82-30f0-4478-bc01-fd4c260f2c5c not found]

Chongqing University

[Person 57eed944-6a57-4d31-9009-7a4aec9f89f8 not found]

Chalmers, Architecture and Civil Engineering, Building Technology

[Person 43caec43-3507-480d-ab02-13fada10bda2 not found]

Shenzhen University

[Person 57347ea7-e8dc-4aef-94b9-558c4bbeb32b not found]

ShenZhen Institute of Information Technology

Journal of CO2 Utilization

22129820 (ISSN)

Vol. 35 303-313

Subject Categories

Inorganic Chemistry

Materials Chemistry

Metallurgy and Metallic Materials

DOI

10.1016/j.jcou.2019.10.001

More information

Latest update

4/1/2020 1