In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint? 1. Copper slag 2. Cold mix asphalt technology 3. Geotextiles 4. Hot mix asphalt technology 5. Portland cement Select the correct answer using the code given below:

Question

YESPYQ · Accepted Answer

Correct answer: 1, 2 and 3 only. Option 1 is correct: Copper slag is a by-product ob- tained during smelting and refining of copper. The use of copper slag in cement and concrete provides potential environmental as well as economic benefits. Option 2 is correct: Cold mix asphalt is produced by mixing unheated mineral aggregate with either emulsified bitumen or foamed bitumen. It is suitable for light to medium trafficked roads when used in base and surface courses. Option 3 is correct: The Government has allowed the use of coir based geotextiles for construction of rural roads under the Pradhan Mantri Gram Sadak Yojana in 2020. Options 4 and 5 are incorrect: Hot Mix Asphalt (HMA) is a com- bination of approximately 95% stone, sand, or gravel bound to- gether by asphalt cement, a product of crude oil. The wide use of hot mix technology leads to environmental pollution as these plants emit a huge amount of greenhouse gases. Portland cement is a major CO2 emitter. 130

Practice more Environment PYQs

More UPSC Environment PYQs