Replacing cement with fly ash results in slower set. Depending on the application and the weather, a slower set can be either an advantage or a disadvantage. Typical additions of fly ash will slow the initial set by 20 minutes and the final set by an additional 20 minutes.
A typical fly ash bend concrete will not require any special finishing considerations. However, because of increased density, higher fly ash blends (i.e. above 20%) will require an adjustment of finishing techniques.
Fly ash concretes are darker and deepen in colour as the dosage increases. However, as the concrete cures and the fly ash is reacted, the colour lightens and becomes very close to 100% Portland cement. The difference is only apparent if closely examined on adjacent pads.
Shaw Resources maintains a rigid quality assurance program which continuously monitors the fly ash through all levels of production. Before dispatch, each and every truck load of product is verified for compliance to carbon content and fitness standards.
