Finnish Association of Construction Product Industries
Construction Product Industries investigated carbon sequestration in concrete
In the Finnish Association of Construction Product Industries action, the carbon storage contained in Finland’s building stock of concrete was analysed. The analysis considered essential factors for carbon sequestration in concrete, such as its hardness and exposure conditions, including moisture and temperature.
It is estimated that the carbon storage in Finland’s existing concrete stock grows by approximately 0.1 Mt of CO2 annually, which corresponds to about 10% of the current annual emissions from Finland’s cement industry. The annual carbon sink from Finland’s concrete stock is around 56 kt, accounting for about 7% of the annual emissions from the cement industry. Finland’s concrete stock permanently sequesters about 4 Mt of carbon dioxide. When concrete is recycled and crushed, the surface area exposed to air increases significantly, thereby enhancing the phenomenon of carbonation, which causes carbon sequestration.
In a pilot conducted from 2021 to 2022, the internal carbonation conditions of crushed concrete mass were investigated, along with ways to enhance carbon sequestration. The results allowed for calculations on how crushed concrete should be processed to optimise carbon sequestration. The findings highlighted, among other things, the impact of different crushing sizes on carbon sequestration. Based on these results, new applications and storage methods for recycled concrete can be designed to enhance natural carbon sequestration.
