Abstract:
Fly ash which is a waste product collected during
coal combustion has become an issue to the environment and
human due to lack of proper disposal methods. The major
barrier of fly ash not being used as a land filling material is its
heavy metal composition. The usage of fly ash in concrete may
also vary with the composition of unburned carbon in fly ash. If
used in optimum proportions fly ash can give many benefits like
cold weather resistance, high strength gains, a good admixture, a
non-shrink material, great workability, reduced crack problems,
reduced heat of hydration and CO2 emissions. Fly ash can be
used in many applications as an additive in building materials
such as bricks, blocks, concrete, road and embankment covers.
Since fly ash is a by-product it possesses a very low embodied
energy which in turn reduces the embodied energy of the product
made out of fly ash to a considerably low value. Therefore, the
introduction of fly ash into cement sand blocks as a raw material
is a better sustainable practice. This research attempt focuses on
finding a feasible and an effective solution for the coal fly ash
problem in fluidized bed boiler and to check the suitability of
coal fly ash cement blocks in building construction. An
appropriate mix proportion for fly ash cement blocks is found
through trial and error process and various different mix
proportions can be tested to obtain a productive and sustainable
result in future as well. Tests done for the determination of
material properties proved that the raw materials used including
fly ash are healthy and robust to be handled and incorporated
into a day to day used product. Tests proved that the substitution
of fly ash has created very less amount of change to the strength
and durability. Also the experiments done on the heavy metal
leachate confirms this product is eco-friendly and human
friendly. Tests done on durability, strength and thermal
properties have confirmed that fly ash can be used as an effective
substitute for sand in cement sand blocks.
