Prelims 2020 · Environment · Question 98
In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint?
- Copper slag
- Cold mix asphalt technology
- Geotextiles
- Hot mix asphalt technology
- Portland cement.
Select the correct answer using the code given below:
Answer
1, 2 and 3 only
1. Copper slag — An industrial by-product that can be used in road construction in place of natural aggregates/fillers, helping waste utilization and lowering resource extraction. Verdict: Correct.
2. Cold mix asphalt technology — Preferred in rural roads because it avoids heating aggregates/bitumen, thus saving fuel and reducing emissions. Verdict: Correct.
3. Geotextiles — Improve subgrade strength, drainage and pavement life, reducing material use and maintenance burden. Verdict: Correct.
4. Hot mix asphalt technology — Requires heating and higher energy input, so it has a larger carbon footprint than cold mix. Verdict: Incorrect.
5. Portland cement — Conventional cement is carbon-intensive in production; it is not preferred on sustainability/carbon-footprint grounds here. Verdict: Incorrect.
Hence, 1, 2 and 3 only are preferred.