Study of stabilized phases in high alumina cement mortars Part I Hydration at elevated temperatures followed by carbonation

The use of temperatures higher than 30°C during the hydration of 1:3 high alumina cement mortar leads to the formation of the cubic hydrate C₃AH₆, hence avoiding the conversion of CAH₁₀ to C₃AH₆. The subsequent carbonation of C₃AH₆ with CO₂ and thermal treatment leads to the formation of stable carbonated phases. The optimum hydration ages are the minimum necessary times to get C₃AH₆: 3 hours at 80°C, 6 hours at 60°C. The product is in a state we call “semiplastic” in which the next structural transformation - carbonation - occurs more easily than when the specimens have a rigid structure. The effect of a super-water-reducing admixture has also been studied.