Activation energy of calcium sulfoaluminate cement-based materials.

In this study, calcium sulfoaluminate (CSA) cement pastes were tested for heat of hydration and chemical shrinkage at temperatures of 20 °C, 30 °C and 40 °C. Apparent activation energy ( E a ) values were then calculated using both exponential and hyperbolic methods. The average E a of the CSA cements ranged from 42.24 to 80.22 kJ/mol, much higher than that of Type I Portland cement (38–45 kJ/mol). E a increased slightly with the replacement of silica fume for cement. However, average E a decreased by 18.4% when 20% Class C fly ash was used, but increased by 21.3% when 40% Class C fly ash was used. E a calculated from heat of hydration using the exponential method is 17% lower than that obtained using the hyperbolic method. When the exponential method was used, E a values determined using heat of hydration were 30% higher than those obtained using chemical shrinkage. [ABSTRACT FROM AUTHOR]