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Furnace Bottom Ash (FBA)

FBA is the "coarse" ash fraction produced by coal-fired power stations when pulverised fuel is burned at high temperatures and pressures. It has similar chemical properties to PFA, consisting predominantly of oxides of silica, aluminium and iron, but has a sand-like gritty texture.


The Specification for Highway Works allows the use of FBA as:

  • Class 1A Well Graded Granular Material
  • Class 6E Selected Granular Fill Material for Stabilisation with cement to form capping
  • 6F1 Selected Granular Material for Fine Capping

Scotash FBA also meets the requirements of BS 3797 (Latest Revision) the specification for lightweight aggregates for masonry units and structural concrete.

Uses and Benefits

FBA is used as a lightweight aggregate in the manufacture of building blocks and other products for the construction industry. It can also be used in foamed concrete as a trench fill and as a structural lightweight fill material, such as in embankments on soft or poor ground conditions.

FBA is also popular as a free draining base and growing media in the fairways and greens of golf courses, for example, and in equestrian arenas.