1. Strength and Activity Index
S95 GGBS: This grade has a strength activity index of ≥95% relative to standard cement, meaning it provides good cementitious properties but does not achieve ultra-high early strength.
S105 GGBS: This grade has a higher strength activity index of ≥105%, making it more reactive and effective in enhancing concrete strength, particularly in early-stage curing.
2. Fineness and Reactivity
S95 GGBS: Typically has a Blaine fineness of around 4000–4500 cm²/g, making it suitable for general concrete applications.
S105 GGBS: Has a higher fineness, often exceeding 5000 cm²/g, increasing its reactivity and ability to fill microvoids in concrete, improving durability and strength.
3. Applications
S95 GGBS: Commonly used in general concrete, cement blending, and mass concrete structures where durability and long-term strength gain are desired.
S105 GGBS: Preferred for high-performance concrete (HPC), ultra-high-performance concrete (UHPC), and precast applications, where its superior fineness and activity enhance workability and early strength.
4. Comparison with Silica Fume
While S105 GGBS has improved fineness and reactivity compared to S95, it is not fully equivalent to silica fume in performance. Some similarities exist, but there are key differences:
Silica Fume (Microsilica): Extremely fine (Blaine fineness >15,000 cm²/g) and consists mainly of amorphous silicon dioxide (SiO₂), making it an excellent pozzolanic material that significantly enhances strength, durability, and impermeability.
S105 GGBS: While it has higher reactivity than S95, it does not achieve the same extreme fineness or pozzolanic reaction as silica fume. However, it can serve as a cost-effective alternative in some high-performance applications where moderate improvements in strength and durability are required.