The carbonation of OPC and OPC/silica fume hardened cement pastes in air under conditions of fixed humidity

Abstract

Slices of hardened pastes of OPC and an OPC/silica fume blend of the same water: solids ratio of 0·5 were carbonated in air for 116 days at a fixed relative humidity. The blended paste slices were found to have carbonated less overall, and to a lesser depth, than the OPC slices. The microstructures of the partially carbonated slices were examined by transmission electron microscopy, and in the case of the OPC the silicate structure was investigated by 29Si NMR.