Green concrete is a revolutionary topic in the field of concrete industry. This was first invented in Denmark in the year 1998. Concrete that uses less energy in its production and produces less CO2. It is environment friendly concrete. Green concrete has nothing to do with the color. In 1997, the Kyoto protocol was signed which required the countries to cut down their CO2 emission as assigned. After this, Denmark focused on cement and concrete production because approximately 2% of Denmark’s total CO2 emission stem from cement and concrete production. Due to growing interest in sustainable development, engineers and architects were motivated more than ever before to choose concrete that is more sustainable.

Materials for Green Concrete:

  • Locally available: Construction materials, components, and systems found locally or regionally, saving energy and resources in transportation to the project site.
  • Salvaged, Re-furnished, or Re-manufactured: Includes saving a material from disposal and renovating, repairing, restoring, or generally improving the appearance, performance, quality, functionality, or value of a product.
  • Reusable or Recyclable: Select materials that can be easily dismantled and reused or recycled at the end of their useful life.

The materials may be listed as:
1. Recycled Demolition Waste Aggregate
2. Recycled Concrete Aggregate
3. Blast furnace Slag
4. Manufactured Sand
5. Glass Aggregate
6. Fly ash

Mix Design: It optimizes void space between aggregates by optimizing particle proportions and packing of materials. This makes more effective use of the cement binder. Aggregates replace excess cement paste to give improved stability, less shrinkage and increase in strength & durability. Less cement also generates less heat of hydration. The slump of the concrete and its flow are a function of the shape &the quantity of the predominant size of the aggregate in the mix. Use of more fine aggregate gives higher slump & flow. So the optimum proportions of coarse & fine aggregate must be critically found to have the best and dense concrete in both fresh & hardened stage of concrete.

Conclusions: Green concrete having good thermal and fire resistant. The water absorption of green concrete is slightly higher than conventional concrete. The durability of green concrete under sulphate is higher to that of conventional concrete.

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