Q. 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:

  • 1, 2 and 3 only
  • 2, 3 and 4 only
  • 4 and 5 only
  • 1 and 5 only

Answer: (a) 1, 2 and 3 only

Notes:

  • The use of copper slag in cement and concrete provides potential environmental as well as economic benefits for all related industries.
  • Particularly in areas where a considerable amount of copper slag is produced.
  • Production of cold asphalt mix does not require high investment in equipment.
  • This makes it economically relatively pollution-free (no objectionable fumes or odors). 
  • Cold asphalt mixes can be used both for initial construction (100% virgin mixes) and for recycling of asphalt pavements.
  • Geotextiles are mostly used in road construction, especially to fill gaps between the roads to improve soil structure.
    • Geotextile makes poor soil more beneficial for use and then easy to build in difficult places also.
    • It helps to prevent the erosion of soil but allows the water to drain off.
  • Portland cement and hot asphalt mix are the major CO2 emitters.
  • Hot Mix Asphalt (HMA) is a combination of approximately 95% stone, sand, or gravel bound together by asphalt cement, a product of crude oil.