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