Term: Ground granulated blast-furnace slag
**Production and Composition of Ground Granulated Blast-Furnace Slag:**
– Chemical composition varies based on raw materials in iron production process
– Silicate and aluminate impurities combine in blast furnace with flux
– Slow cooling results in unreactive crystalline Ca-Al-Mg silicates
– Granulation process used to cool and fragment slag for suitable reactivity
**Applications of GGBS:**
– Used in Europe, US, and Asia for durable concrete structures
– Major uses include quality-improved slag cement and ready-mixed durable concrete
– Sets slower than ordinary Portland cement, providing lower heat of hydration
– Reduces risk of damages from alkali-silica reaction and reinforcement corrosion
– Provides higher resistance to chloride ingress and attacks by sulfate and other chemicals
**GGBS Cement Uses and Benefits:**
– Added to concrete as replacement for Portland cement
– Replacement levels vary from 30% to 85%, with typical use between 40% to 50%
– Provides durability against sulfate and chloride attack
– Offers near-white color for exposed fair-faced concrete finishes
– Concrete with GGBS has higher ultimate strength than Portland cement
**Architectural and Engineering Benefits of GGBS:**
– Bulk Electrical Resistivity test indicates higher durability with GGBS
– Helps limit temperature rise in large concrete pours, reducing thermal gradients
– Prevents efflorescence and staining of concrete surfaces
– Recognized by LEED and BEAM Plus for sustainability
– Optimal GGBS dosage in concrete is 20-30% by mass for higher compressive strength
**Sustainability and External Resources on GGBS:**
– By-product of steel manufacturing, improving project sustainability
– Can be used for superstructure and in chloride/sulfate contact cases
– Various citations and studies on GGBS performance in concrete
– External links for more information and resources on GGBS
Ground granulated blast-furnace slag (GGBS or GGBFS) is obtained by quenching molten iron slag (a by-product of iron and steel-making) from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder. Ground granulated blast furnace slag is a latent hydraulic binder forming calcium silicate hydrates (C-S-H) after contact with water. It is a strength-enhancing compound improving the durability of concrete. It is a component of metallurgic cement (CEM III in the European norm EN 197). Its main advantage is its slow release of hydration heat, allowing limitation of the temperature increase in massive concrete components and structures during cement setting and concrete curing, or to cast concrete during hot summer.
