Reports on CO2 Uptake from the Carbonation of Concrete - Guidelines

Uptake of carbon dioxide in the life cycle inventory of concrete
by K. Pommer & C. Pade, Danish Technological Institute, Denmark (www.danishtechnology.dk)

Abstract
During the production of Portland cement based products energy is consumed and consequently CO₂ is emitted to the atmosphere. Inherent to the production of Portland cement is the calcinations of limestone resulting in the emission of 44 kg CO₂ per 100 kg of pure limestone (CaCO₃) fed to the clinker kiln. However, once the Portland cement is used for concrete the concrete will start to undergo a carbonation process during which CO₂ will be taken up by the concrete. In the NICe project "CO₂ uptake during the concrete life cycle" the carbonation rate of different concrete types under various conditions has been assessed including the rate of carbonation during secondary life i.e. after demolition and crushing of the concrete. Also, the project estimated the annual production of various concrete types and products. The present “Guidelines - Uptake of carbon dioxide in the life cycle inventory of concrete” represents, based on the findings of the NICe project, an attempt to establish a generic procedure of CO₂ life cycle inventory that adequately includes all phases in the life and secondary life of any concrete product.