Acceleration of Hydration of Calcium Silicates by Carbon Dioxide Treatment

LIME mortars were one of the first cementitious materials and were used extensively in Greek and Roman times. Strength development by the reaction of atmospheric CO2 with Ca(OH)2 to form CaCO3 is slow because the carbonation reaction is controlled by the diffusion of CO2 at small partial pressures. If high partial pressures of CO2 are used, however, Ca(OH)2 can carbonate very rapidly and recently compressive strengths of 2,000–4,000 pound inch2 have been achieved in compacted blends of lime with soils1 and coal refuse2. The experimental data2, 3 suggest that the carbonation reaction is taking place primarily in the aqueous film surrounding the particles.