Case Study of the Day: Solar Energy to Recycle Waste Concrete

Context: The researchers at IIT Madras have developed and demonstrated a treatment process that uses solar thermal energy to recycle waste concrete from construction and demolition debris.

About the New Process

• The researchers demonstrated the technology at Solar Thermal Power Plant in Rajasthan, where they used the large reflectors of the solar concentrators to heat concrete rubble from demolition sites in cast iron receivers, post which they mechanically scrubbed the material to yield coarse and fine recycled concrete aggregate (RCA).
• These RCA materials can be used to replace “blue metal” (stone used for construction) and sand used in concrete construction.
• Advantage: There are no significant by-products in the process, apart from emission of water vapour but certainly nothing toxic.
• Significance of research: The demand for concrete in India is met by extensive mining and quarrying operations, which deplete important primary resources, while leading to pollution of air, soil and waterways. It is here, where the concrete recycling process could come handy.
• Challenges/Drawbacks
  • Process is highly susceptible to interruption due to weather events, as it could be unviable during rainy or cloudy days.
  • Initial capital investment due to the need to build large-scale heating plants with solar energy concentrators.
  • Building an Extensive logistics network also might be a challenge, as it involves collection and separation of recyclable concrete from construction and demolition sites.

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