Hydration heat and kinetics of composite binder containing blast furnace ferronickel slag at different temperatures

The hydration heat of composite binder containing up to 70 % blast furnace ferronickel slag (BFFS) was determined at 25 degrees C, 45 degrees C and 60 degrees C. The hydration kinetics process and parameters were simulated and analysed. BFFS shows pozzolanic activity in a strong alkaline solution. Increasing the BFFS content retards hydration and reduces the exothermic rate. The high temperature dramatically promotes hydration, especially for the composite binder containing no more than 30 % BFFS. The hydration kinetics process involves nucleation and crystal growth (NG) -> interactions at phase boundaries (I) -> diffusion (D) at 25 degrees C and 45 degrees C. However, this process becomes NG -> D at 60 degrees C. The addition of BFFS decreases the overall hydration rate. BFFS has a smaller effect on the overall hydration of the composite binder than ground granulated blast furnace slag, but has a greater effect than fly ash.

Automated summary

The influence of BFFS on hydration depends on temperature and BFFS content, with higher temperatures promoting hydration while increasing BFFS content slowing it down and reducing the exothermic rate. The hydration process involves nucleation and crystal growth, followed by interactions and diffusion.