Supplementary Cementing (Cementitious) Materials
Supplementary cementing materials (SCMs) are materials that, when used in conjunction with portland cement or blended cements, contribute to the properties of hardened concrete through hydraulic or pozzolanic activity or both. Examples of supplementary cementing materials include ground granulated blast furnace slag (GGBFS), a by-product of the iron industry, and fly ash, a by-product of coal combustion in power plants.
Fly ash is the fine ash resulting from burning coal in electric utility plants. It is used as a mineral admixture for many high-performance concretes. Its many performance-enhancing properties and typically lower cost have made fly ash one of the key ingredients in modern concrete production.
Fly ash has many other uses, as well. For example, it is suitable for geotechnical applications for:
- soil stabilization
- soil drying
- stabilizing aggregate bases
- structural fill
- bituminous pavement recycling
- reducing shrink/swell in expansive clay soils
SCMs and blended cements offer sustainable and performance advantages for those who build and occupy structures of all kinds. The growing use of these environmentally friendly materials is due in part to numerous performance factors, including low permeability, resistance to chlorides and sulfates, mitigation of alkali silica reaction, greater strength, lower temperatures for mass concrete, and improved workability.
The use of cementitious blends not only results in stronger, more durable high-performance concretes, but also helps reduce global climate impact by lowering energy consumption and greenhouse gas emissions.
These materials provide a significant contribution to sustainable construction. The use of these materials in concrete production consumes less energy and offers improved efficiency and building performance. These materials can be used to achieve LEED (Leadership in Energy and Environmental Design) points.