
79Coal Combustion Waste Materials
Portland cement, although higher substitution rates can be used, depending on the
application. Specic benets derived from using y ash include improved workability,
decreased water demand, increased ultimate strength, reduced permeability, and
improved durability (ACAA, 2003). In addition, cost savings are provided as y ash
is generally less expensive than Portland cement.
3.2.1.2.2 Raw Feed for Portland Cement Clinker
Portland cement is the basic ingredient in concrete and is produced by heating
a combination of oxides of calcium, silicon, aluminium, and iron to produce
cement that meets specic chemica