The influence of pozzolanic additives on the carbonation rate and Life Cycle Inventory of concrete

Abstract

Reduction of carbon dioxide emission has become the major environmental and social challenge in recent time. Therefore a lot of attention is paid to CO2 uptake of concrete in carbonation process. The existing approaches substantially overestimates the absorption of carbon dioxide during concrete carbonation. In the paper the modification of CO2 uptake models according to recent finding described in literature as well as considering the pozzolanic reaction has been presented. The proposed formulas have been verified against the results of performed laboratory research. Three Self – Compacting Concretes have been put to carbonation chamber for 168 days in the controlled conditions. Studied samples were of cubic shape and crushed aggregate, which reflected the concrete after demolition. Progress of carbonation front was determined by phenolphthalein indicator and Fourier Transformation Infrared Spectroscopy analysis. Maximum amount of CO2 uptake was measured with Termogravimetric Analysis and Differential Thermal Analysis. Results of laboratory research have been compared with proposed models and the formula defining the maximum theoretical CO2 uptake for totally carbonated concrete given in Standard EN – 16757:2017. Next achieved values have been applied in a Life Cycle Inventory.