Fly Ash

What are the benefits of using Fly Ash?
It is widely used in the UK to increase the strength of concrete, and to improve workability of fresh concrete. It reduces water demand, shrinkage and permeability of the finished product. As it is a waste product, which would otherwise go to landfill, fly ash can significantly reduce the carbon footprint of concrete. It is viewed increasingly as a vital ingredient in low-carbon blended cements such as CEM II (see CEM II Blended Cements)

What is Fly Ash?
Fly ash is the fine ash produced at coal-fired power plants that develops cementitious properties when mixed with cement and water. Fly Ash is a pozzolan, meaning it is a siliceous and aluminous material that, in the presence of moisture, will combine with the lime liberated during the hydration of cement to form cementitious materials.

Where does it come from?
Fly Ash is a by-product of coal-fired electric generating plants. The coal is pulverized and blown into burning chambers for immediate combustion. Heavier ash particles (bottom ash or slag) fall to the bottom of the burning chamber and the lighter ash particles (Fly Ash) fly out with the exhaust gas, thus the term Fly Ash. Before leaving the stack, these Fly Ash particles are removed and collected by electrostatic precipitators, bag houses or other methods.

In which applications can Fly Ash be used?

• Ready-mix concrete
• Concrete block, paving and pipe products
• Blended cements e.g. CEM II
• Mineral filler for asphalt roads
• Soil stabilisation
• Structural fill
• Waste stabilisation/treatment