Concrete is building material made by mixing cement, sand, water and gravel or other materials with then hardens over time. It is said to be the second-most used substance in the world after water with annual production pegged at over 10 billion tonnes.
Conventional concrete is not eco-friendly because of the cement in its mix. Green concrete is a sustainable substitute which uses at least one waste or recycled material as its component. Its production consumes less energy and produces less CO2.
8-10 per cent of the world’s total CO2 emissions come from manufacturing cement. It is released when limestone and clay are crushed and heated to high temperatures.
Cleaner technologies are being employed to make concrete green by substituting the high percentage of cement used with fly ash and using waste materials.
According to estimates, in 2021-22 the demand for cement in India was 380 mt. Construction and demolition (C&D) waste in India yields concrete which when processed can be used to manufacture green cement. The government is currently focusing on 100 per cent utilisation of waste material from the C&D industry.