Fly ash brick
![](/Images/godic/202501/13/Fly_ash_bricks4458.jpg")
![Funton Creek. Presumably this was a navigable channel in the days when the brick works was serviced by barges bringing fly-ash from London and returning with loads of bricks.](/Images/godic/202501/13/Funton_Creek_-_geograph.org.uk_-_43364458.jpg")
Fly ash brick (FAB) is a building material, specifically masonry units, containing class C fly ash and water. Compressed at 28 MPa (272 atm) and cured for 24 hours in a 66 °C steam bath, then toughened with an air entrainment agent, the bricks last for more than 100 freeze-thaw cycles. Owing to the high concentration of calcium oxide in class C fly ash, the brick is described as "self-cementing". The manufacturing method saves energy, reduces mercury pollution, and costs 20% less than traditional clay brick manufacturing.