New predictive methodology for the apparent activation energy and strength of conventional and rapid hardening concretes

Evaluation of Strength Development in Concrete with Ground Granulated Blast Furnace Slag Using Apparent Activation Energy

“…When mortar with 50% GGBFS was cured at 5 • C and 35 • C, the final setting time was delayed by 16.9 h. The largest difference in the final setting time was 23.7 h between 50% GGBFS at 5 • C and OPC at 35 • C. It is considered that impermeable film has formed when GGBFS particle reacts with water. Due to the formation of the impermeable film results in the delay of hydration reaction, which restraining the penetration of water and ion [44][45][46][47]. Thus, this result suggests that the setting quickly occur owing to the fast reaction of hydration caused in early age at high temperature.…”

“…It has been reported that E a can vary owing to the nature of Portland cement, which has different hydration reaction patterns with the setting process, curing period, and cementitious components [38]. Some researchers have reported that E a is approximately 33.5 to 47.0 kJ/mol at early-age, and approximately 10 to 30 kJ/mol at long-term age [39][40][41][42][43][44][45][46][47][48][49]. Freisleben-Hansen and Pederson (FHP) [13] proposed an equation (Equation 7) to estimate E a of OPC concrete as a function of curing temperature.…”