Determination of the apparent activation energy for composite binder containing blast furnace ferronickel slag

Blast furnace ferronickel slag (BFFS) has the potential to serve as a supplementary cementitious material (SCM) in the production of cement and concrete. While the composite binder containing BFFS presents varying heat release kinetics under different curing temperatures, the effect of BFFS content on the apparent activation energy (E-a) and temperature sensitivity of the composite cementitious binder has rarely been systematically explored. In this study, the modified ASTM C1074 method with hyperbolic and exponential functions is adopted to calculate the E-a values of the composite binders incorporating different amounts of BFFS via isothermal calorimetry. The results indicate that the calculated E-a values are influenced by different kinetic functions, and increasing the BFFS content from 0 to 50% has significantly elevated the E-a value and enhanced the temperature dependence of BFFS blended cement paste. Moreover, the temperature sensitivity of the composite binder containing BFFS is compared to those containing traditional SCMs, including ground granulated blast furnace slag (GGBFS) and low-calcium fly ash (FA). The study reveals that the E-a value of 50% BFFS blended cement paste is close to that of 50% GGBFS blended cement paste, and higher than that of 50% low-calcium FA blended cement paste. The high temperature sensitivity of BFFS blended cement can be leveraged to promote the early-age strength gain under different curing temperatures.

Automated summary

Blast furnace ferronickel slag (BFFS) can be used as a supplementary cementitious material (SCM) in cement and concrete production. The research focuses on the effect of BFFS content on the apparent activation energy (E-a) and temperature sensitivity of the composite cementitious binder. The results showed that increasing BFFS content significantly elevated the E-a value and enhanced the temperature dependence of the BFFS blended cement paste.