Q: With reference to ‘fly ash’ produced by the power plants using coal as fuel, which of the following statements is/are correct?
Fly ash can be used in the production of bricks for building construction.
Fly ash can be used as a replacement for some of the Portland cement contents of concrete.
Fly ash is made up of silicon dioxide and calcium oxide only, and does not contain any toxic elements.
Select the correct answer using the code given below:
a) 1 and 2
b) 2 only
c) 1 and 3
d) 3 only
The correct answer is 1 and 2.
Fly ash
It is the finely divided residue that results from the combustion of pulverised coal and is transported from the combustion chamber by exhaust gases.
It is produced by coal-fired electric and steam-generating plants.
It is used annually in a variety of engineering applications that include: Portland cement concrete (PCC), soil and road base stabilization, flowable fills, grouts, structural fill and asphalt filler. Hence, Statement 1 is correct.
extending the lifespan of concrete structures and roadways by enhancing concrete durability, Hence, Statement 2 is correct.
a decrease in energy consumption, greenhouse gas emissions, and other harmful air emissions when fly ash is utilised in place of or in addition to made cement,
a decrease in the volume of coal combustion waste that must be dumped in landfills, and
protection of other materials and natural resources.
It consists primarily of oxides of silicon, aluminium iron and calcium. Magnesium, potassium, sodium, titanium, and sulphur are also present to a lesser degree. Hence, Statement 3 is not correct.
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