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:
Answer & explanation
Answer: (a) 1, 2 and 3 only
Copper slag, cold mix and geotextiles are the green options for rural roads: they reuse industrial waste, save the fuel needed to heat bitumen, or cut the stone and soil needed. Hot mix asphalt and Portland cement are the conventional, energy-hungry materials.
- ✓ 1. Iron, steel and copper slag are on the list of proven technologies with Indian Roads Congress specifications (IRC SP:121-2018) that the rural roads agency (NRIDA) promotes; using this waste reduces demand for quarried aggregate.
- ✓ 2. Cold mix does not require heating the bitumen, which saves fuel and reduces pollution, and PMGSY lists it as a green technology.
- ✓ 3. Geotextiles, such as coir, strengthen the sub-grade soil and protect slopes, and the Rural Development Ministry lists coir geo-textiles among the new technologies under PMGSY.
- ✗ 4. Hot mix needs bitumen and aggregate to be heated, which is exactly what cold mix avoids, so it is the conventional, higher-fuel method.
- ✗ 5. Portland cement is the conventional binder; PMGSY's green list is about waste materials, cold mix, waste plastic and geosynthetics, not adding Portland cement.
Remember · Under PMGSY, green rural-road technologies include cold mix, waste plastic, industrial slags and geotextiles, which save fuel and natural aggregate.
Sources
- Adopting Green and New Technologies in PMGSY (NRIDA, Ministry of Rural Development), Internet Archive copy ↗ “In this technology heating of bitumen is not required resulting in saving in fuel and thereby saving of environment.”
- New Technology Initiatives in Rural Roads and Use of Marginal Materials (NRIDA, PMGSY), Internet Archive copy ↗ “Construction & Demolition Waste – IRC 121-2017 Recycling of Bituminous Pavement – IRC120-2015 Iron, Steel & Copper Slag – IRC SP121-2018”
- PIB, Ministry of Rural Development: Use of coir geo textiles in construction of roads under PMGSY (3 August 2021) ↗ “Coir geo-textiles are used for improvement of sub-grade soil strength in road pavements and stabilization of side slopes.”
Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·