Sequestration of carbon dioxide by concrete infrastructure: a preliminary investigation in Ireland

Abstract

Assumptions that the net contribution of cement and concrete production to greenhouse gas levels are represented by carbon dioxide (CO₂) emissions alone are inaccurate. The net contribution of CO₂ released through calcination of limestone may be over 20% less on a global scale. This is due to CO₂ uptake by concrete products in service through the naturally-occurring phenomenon of carbonation of concrete. Failure to take account of the net effect may lead to misinformed policy formulation on global and regional climate change strategies. Accurate quantification of these figures and incorporation of this concept intolife-cycle assessment studies will permit a more realistic comparison to be made of the true environmental impact (CO₂footprint) of future concrete structures.

This paper presents the methodology and findings of a preliminary investigation into the sequestration of CO₂ by concrete in Ireland.  The process of concrete carbonation is well known and models for the process underpin concrete durability design in current European concrete standards.  Despite this, CO₂ sequestered by concrete in and after service is not generally accounted for in determinations of environmental impact.  Using methodologies developed from similar work in Scandinavia, this paper details the development of initial estimates of the quantity of the CO₂ immobilised by Irish concrete in service over time, as a fraction of the CO₂ released through calcination of limestone.  Possible implications of the preliminary findings and potential avenues for future research are outlined

DOI: http://dx.doi.org/10.5755/j01.sace.10.1.8037