Introduction
The concrete is made with concrete wastes which are eco-friendly so called as Green concrete.
The other name for green concrete is resource saving structures with reduced environmental impact for e.g. Energy saving, co2 emissions, waste water.
Green concrete is a revolutionary topic in the history of concrete industry.
What is green concrete
- Most people associate GREEN concrete with concrete that is coloured with pigment.
- However, it is also referred which has not yet hardened. But in the context of this topic, green concrete is taken to mean environmentally friendly concrete.
- This means concrete that uses less energy in its production & produces less carbon dioxide than normal concrete is green concrete.
Why Green Concrete
- The main ingredient in concrete is cement and it consists of Limestone (Calcium Carbonate CaCO3).
- During manufacture of cement, its ingredients are heated to about 800 – 10000C.
- During this process the Carbon Dioxide is driven off.
- Approximately 1kg of cement releases about 900gms of Carbon Dioxide into the atmosphere.
- Therefore, green concrete came into existence to reduce the emission of carbon dioxide.
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.
Materials for Green Concrete
- Recycled Demolition Waste Aggregate
- Recycled Concrete Aggregate
- Blast furnace Slag
- Manufactured Sand
- Glass Aggregate
- Fly ash
Mix Design
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.
Advantages
- User-friendly
- Optimized mix designs mean easier handling, better consistency and easier finishing
- Reduction in shrinkage & creep
- Green Concrete uses local and recycled materials in concrete.
- The heat of hydration of green concrete is significantly lower than traditional concrete
- This result in a lower temperature rise in large concrete pours which is a distinct advantage for green concrete.
Its nice to see old concrete being recycled and made new again. I was unaware of the other materials that are also added into the mix for green concrete.