With reference to ‘fly ash’ produced by the power plants using coal as fuel, which of the following statements is/ are correct? 1. Fly ash can be used in the production of bricks for building construction. 2. Fly ash can be used as a replacement for some of the Portland cement contents of concrete. 3. 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 codes given below.

With reference to ‘fly ash’ produced by the power plants using coal as fuel, which of the following statements is/ are correct? 1. Fly ash can be used in the production of bricks for building — UPSC Prelims 2015 Answer & Explanation

Science & Technology2015

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
Fly ash can be used as a replacement for some of the
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 codes given below.

Explanation

The correct statements regarding fly ash are 1 and 2. Fly ash is a byproduct of coal combustion in power plants and is rich in silica, alumina, and iron oxide, making it suitable for use in the production of bricks and as a partial replacement for Portland cement in concrete, enhancing the material's durability and strength. However, statement 3 is incorrect because fly ash can contain various toxic elements, including heavy metals, arising from the impurities in coal, which can pose environmental and health risks if not managed properly. This understanding is crucial in the context of sustainable construction practices and waste management in civil engineering.

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