Why in news?
On 26 March 2026 the CSIR‑Central Road Research Institute (CRRI) signed a collaboration with the Institute of Indian Foundrymen and a private partner to integrate waste foundry sand into India’s road construction programme. The initiative seeks to replicate the success of steel‑slag roads by turning discarded casting sand into durable highway sub‑base material. This partnership aims to develop protocols, training programmes and pilot projects that make industrial waste a valuable resource in infrastructure.
Background
Foundries create metal parts by pouring molten metals into moulds made of sand. After the metal solidifies the sand moulds are broken and much of the sand becomes a waste product. Two main types of foundry sand are used:
- Green sand: Comprises high‑quality silica mixed with 5–10 percent bentonite clay, 2–5 percent water and about 5 percent sea‑coal to improve the finish of castings. Because green sand can be reused only a limited number of times, large quantities are eventually discarded.
- Chemically bonded sand: Uses resins or other binders to form moulds for precision casting. These sands are difficult to recycle and are typically disposed of after a single use.
Disposal of waste foundry sand (WFS) is a challenge because it occupies land, can leach chemicals if not properly managed and often ends up in landfills. Globally, researchers have experimented with using WFS in building materials, concrete and soils to promote a circular economy.
How will the programme work?
- Characterising waste sand: CRRI scientists will analyse samples from different foundries to understand grain size, chemical composition and leachability so that guidelines can be customised for Indian conditions.
- Developing road‑building protocols: Based on laboratory tests the partners will prepare standard procedures for blending WFS with natural aggregates in sub‑base layers. The aim is to ensure adequate compaction, strength and drainage while keeping costs low.
- Training and pilot projects: Engineers, contractors and public works departments will be trained to implement the new protocols. Demonstration stretches of road will showcase how WFS performs under real traffic loads.
- Circular economy benefits: Using WFS reduces the need for virgin sand and gravel, diverts industrial waste from landfills and cuts greenhouse‑gas emissions associated with quarrying. It also opens new revenue streams for foundries.
Significance
- Conserving natural resources: India’s road sector consumes enormous quantities of aggregates. Incorporating foundry sand can ease pressure on rivers and hills where sand is mined.
- Reducing pollution: Properly encapsulated WFS can prevent the leaching of metals and chemicals while mitigating air and soil pollution around foundry sites.
- Promoting innovation: The initiative builds on the success of steel‑slag roads and strengthens the “waste‑to‑wealth” mission by converting industrial by‑products into infrastructure inputs.
Conclusion
Waste foundry sand was long viewed as a disposal problem, but research and pilot projects are turning it into an opportunity. By establishing clear standards and involving both industry and government, the new programme may pave the way for greener roads and a more sustainable manufacturing sector.
Source: Press Information Bureau
