Description
Fly Ash or Pulverised Fuel Ash (PFA) is a by-product resulting from the burning of pulverized coal in coal-fired power stations. A small percentage of the coal forms into fine glass spheres, the lighter of which are borne by the combustion process. It is then extracted from the flue gasses by electrostatic precipitators.
Fly Ash is a pozzolanic material which will not hydrate with water directly but needs lime to hydrate. In concrete, Fly Ash reacts with the lime that arises from the cement hydration to form a stable calcium silicates and calcium aluminate hydrates.
Fly Ash is a supplementary cementitious material that delivers improved workability, later-age strength, and enhances the durability properties of concrete.
Application areas
Fly Ash can be used in almost any applications for concrete containing Portland cement.
- All cement types
- Precast
- Hot weather concreting
- Self consolidating concrete
- Pumped concrete
- Extended workability retention
- Foundation concrete below water table
- Ready-mix concrete
- High durability concrete
- Concrete for highly reinforced structures
- High performance Concrete – Very High Performance Concrete – Ultra High Performance Concrete
- etc
- Low-carbon concrete
Benefits
Although Fly Ash has environmental advantages, it also improves the performance and quality of concrete. It improves workability, reduces water demand, controls bleeding, and lowers heat of hydration.
The use of Fly Ash reduces the temperature rise in thick sections – with the addition of less cement in a concrete mix the heat produced during hydration is significantly reduced.
The Fly Ash reaction with lime reduces permeability, which reduces shrinkage, creep and gives greater resistance to chloride ingress and sulphate attack.
Fly Ash greatly improves the surface finish of the completed structure. It contributes to having a more cohesive concrete which has a reduced rate of bleeding making it easier to compact and giving the concrete better pumping properties.
Packaging
- Bulk delivery on request