RAS question
Fly ash can be used to manufacture which building material that replaces conventional clay bricks?
Correct answer: (D) Fly ash bricks (lighter, stronger, and cheaper).
Fly ash is used to make fly ash bricks, a building material that can replace conventional clay bricks in construction.
Explanation
Fly ash bricks are the building-material use of fly ash that directly replaces conventional clay bricks. They are made by mixing fly ash, cement, sand and water, and they are lighter, more uniform, stronger and cheaper than clay bricks. Their environmental advantage is also central: they do not need kiln firing, so they save topsoil and energy. The Press Information Bureau, Ministry of Coal noted that traditional clay bricks were replaced with fly ash bricks in construction works such as drains, sanitation works, compound walls, dwellings, office buildings and public buildings. That is why, among the options, the only material tied to fly ash and clay-brick substitution is fly ash bricks.
Why the other options are wrong
- (A) Glass panels are wrong because the question asks for a fly-ash-based replacement for clay bricks, while glass is made from silica sand rather than fly ash.
- (B) Rubber tiles are wrong because rubber comes from a different raw material stream and is not the fly-ash product described as replacing clay bricks.
- (C) Plastic sheets are wrong because plastic is petroleum-based and does not match the fly-ash brick use explained for construction masonry.
Concept
This tests waste-to-resource applications under environment-linked science and technology. It recurs in RAS because fly ash connects thermal power pollution, construction materials, resource efficiency and government utilisation policy in one examinable topic.