What happens to concrete waste after a building is demolished? Most of it ends up crowding landfills or just lies there by the road for months until authorities intervene.

If their innovation succeeds and is adopted, then concrete waste could be transformed into building blocks for new structures.

The innovation, by a team of Kongu Engineering College, Erode, has won an award at IIT Madras’ Carbon Zero Challenge competition.

Method :

  • The method is a simple and economical.
  • Under this, the first step is to segregate concrete waste from the C&D debris.
  • It is then crushed to produce recycled aggregates of different particle sizes.
  • Sodium silicate is then added to this concrete waste, which not only helps reduce porosity but also increases durability. It plays a vital role in helping the material bind well.
  • This mixture then undergoes a carbonation process. It is a process where carbon dioxide is injected into it at varying pressures in a chamber.
  • Once carbonated, it is mixed with cement and water to create blocks. These blocks are the then sprayed with water again and sundried for curing.
  • “Injection of CO2 will improve the physical properties including the density of the aggregate. Such properties are important for the durability of the block, as most recycled bricks are known to crack faster.

Also, there is no need to add water for curing, as we have added sodium silicate to the crushed particles,” Dr Rampradeep.

  • These blocks were tested by the team for compressive strength and were found to be stronger and more durable than conventional bricks and concrete blocks.
  • The Kongu Engineering team has applied for a patent for both the technology and for the equipment used for processing the waste

If this innovation is put to use, it could help solve the concrete waste problem in the city which generates over 1,200 tonnes of C&D waste every day. Civic body officials in the city reveal that less than 1% of this waste is being processed or recycled.

The Chennai Corporation has now identified two erstwhile landfill sites in Athipattu and Pallikaranai to process the waste

Prof Rampradeep expresses that the adoption of this technology will not only convert waste into wealth but also cut down CO2 emissions drastically.

We wish the team of engineering students all the very best and hope this much-needed innovation is adopted by cities in India.

Kongu Engineering College

Tamil Nadu