Effects of Thermal Activation on Mechanical Performance and Sustainability of Slag-Based Geopolymers

Ground granulated blast furnace slag (GBFS)-based geopolymers represent a viable binder system that combines mechanical efficiency with a significantly lower carbon footprint
when compared to conventional Portland cement. This work examines how thermal curing between 20 ◦C and 80 ◦C affects setting time, mechanical performance, shrinkage,
and porosity of GBFS-based geopolymers. Curing at 40 ◦C accelerated gel formation, yielding compressive strengths up to 71.9 MPa. This regime also reduced shrinkage and
porosity. In contrast, curing at ≥60 ◦C caused structural degradation and reduced longterm performance. Statistical analysis (ANOVA and Tukey post hoc) confirmed significant
effects of curing regime and age on performance. These findings provide key insights for optimizing thermal curing of slag-based geopolymers, supporting their deployment in environmentally responsible construction practices.