In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint? 1. Copp

1. A. 1, 2 and 3 only
2. B. 2, 3 and 4 only
3. C. 4 and 5 only
4. D. 1 and 5 only

Answer: A

Explanation

The use of waste materials in the road construction industry is gradually gaining significance in India, considering disposal and environmental problems and the gradual depletion of natural resources. Byproducts, such as biomass ash, coal ash, red mud and copper slag, generated in large volumes, could have applications in the construction of roads, buildings and bridges. Option 1 is correct: 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. Option 2 is correct and Option 4 is not correct: Cold asphalt mix is produced by mixing unheated mineral aggregate with either emulsified bitumen or foamed bitumen. Unlike hot mix asphalt (HMA), cold asphalt mix does not require any heating of aggregate which makes it economical and relatively pollution-free (no objectionable fumes or odours). Production of cold asphalt mix does not require high investment in equipment, which makes it economical. It is also suitable for use in remote areas. Cold asphalt mixes can be used both for initial construction (100% virgin mixes) and for recycling of asphalt pavements. Option 3 is correct: 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. Option 5 is not correct: roducing the portland cement that binds concrete together is energy intensive and emits enormous amounts of carbon dioxide (CO 2) as well as numerous other pollutants.