Precipitation

Carbonation

Physics

Engineering

Meteorology

Composite material

Chemistry

Metallurgy

Materials science

Mineralogy

Portlandite

Ettringite

Vaterite

Calcium carbonate

Carbonatation

Aragonite

Portland cement

Calcite

Carbonate

Chemical engineering

Cement

Microstructure

Cement and Concrete Research

The consequences of accelerated carbonation at 3% CO2 were compared with those of natural carbonation (0.04%). Cement pastes (CEM I and CEM V/A) as well as the three major constitutive phases (C-S-H of different C/S ratios, portlandite and ettringite) were used and changes in the mineralogy, microstructure, water retention and cracking were investigated. The main conclusion was that accelerated carbonation at 3% CO2 was representative of natural carbonation although it promoted the precipitation of metastable calcium carbonate (aragonite and vaterite) in place of calcite. The results also showed that the presence of aragonite and vaterite were characteristic of the carbonation of ettringite and C-S-H respectively.

Comparison between natural and accelerated carbonation (3% CO2): Impact on mineralogy, microstructure, water retention and cracking