SEM-EDS analysis of products formed under natural and accelerated carbonation of concrete with CEM I, CEM II/B-M and CEM II/B-V

Abstract

Carbonation resistance of concrete is usually tested under accelerated conditions, i.e. by elevating the CO2 concentration compared to natural conditions and keeping the RH close to 60%. However, it is not clear if these conditions mirror the natural process. Using SEM-EDS we investigated the composition of the reaction products of carbonated and non-carbonated concrete containing 0, 18 and 30% fly ash exposed to three different carbonation conditions. In noncarbonated concrete the reaction products depended on the binder. However, in carbonated concrete the reaction products were similar in composition in all the concretes and exposure conditions tested.