Sustainable Rural Road Construction

Using industrial waste like copper slag reduces the need for virgin aggregates, promoting sustainability (1 is correct). Cold mix asphalt is mixed at ambient temperatures, heavily reducing the fuel consumption and carbon footprint compared to energy-intensive Hot mix asphalt (2 is correct, 4 is incorrect). Geotextiles prevent soil erosion and improve road longevity sustainably (3 is correct). The manufacturing of Portland cement is one of the largest global sources of CO2 emissions, making it terrible for reducing carbon footprints (5 is incorrect). > One-line conceptual takeaway: Sustainable infrastructure prioritizes the use of industrial by-products (slags), ambient-temperature processing (cold mix), and durable synthetic materials (geotextiles). Answer: (a).