Preliminary investigations of the phase composition and fine pore structure of super-critically carbonated cement pastes

摘要

Super-critical carbonation of cement-based materials can lead to significant improvements in their properties. Preliminary investigations suggested that processing should be aimed at producing a matrix material with minimal amounts of Ca(OH)2, anhydrous material and C—S—H gel along with a controlled pore structure. Using 29Si MAS NMR and TGA as the principal investigative techniques it has been shown that moisture content during carbonation is a major factor in determining the phase composition and pore structure of the resulting matrix. Of the drying regimes studied, 60% DOD gave the greatest amount of conversion to calcium carbonate and silica gel.