Evaluation of visual methods for CO2 uptake by demolished concrete: Research activities by JSCE subcommittee 219

In Japan, demolished concrete is often recycled as crusher-run material that captures CO2 because new surface is exposed to the air. This uptake is enabled by carbonations of hydration products in hardened cement paste. The amount of extra CO2 captured during storage varies with the particle size and exposed storage humidity conditions. This paper presents the results of an investigation by the working group of the JSCE subcommittee 219. The group evaluated various methods for visualizing rapid CO2 uptake by demolished concrete. An intuitive and educational method using a gas sampling bag was selected for experimentation.