Green Concrete

Green concrete was 1^st invented in Denmark in 1998. It is a friendly environmentally concrete which is produced using a mixture of non-CO₂ production method or it is concrete which utilizes waste materials as at least one of its ingredients. The production process of green concrete does not lead to environmental destruction.

The word green in green concrete is not just limited to color. The green color represents the environment. It is environmentally friendly concrete. This concrete follows the techniques of reuse-reduce-recycle. Green concrete reduces greenhouse gas emissions.

This concrete is made to waste concrete materials and uses less energy in its production and produces less carbon dioxide than normal concrete. The cement used in green concrete consists of limestone (calcium carbonate CaCO₃). During manufacture, the ingredients of cement are heated to about 800 to 10000-degree centigrade. Carbon dioxide is driven off during the manufacturing process of cement.

Aggregates are the main ingredient in concrete. Due to consistently mining the availability of aggregates have emerged problem in recent time. There is a solution to find some extent and the solution is known as green concrete. For each ton of cement produced about 0.9 tons of carbon dioxide is produced. CO₂ is the greenhouse gas that is responsible for global warming.

Materials for Green Concrete:

1. Fly ash and eco-cement
2. Fly ash aggregates
3. Glass aggregates
4. Reused demolition waste aggregates
5. Reused or recycled concrete aggregates
6. (BFS) blast furnace slag
7. Manufacture sand
8. Rice husk ash: it is hard protecting covering the grains of rice.

Mix-Design

• The concrete mix design method for green concrete is similar to conventional concrete.
• The cement and aggregates used in this concrete must pack themselves in such a manner that they occupy minimum volume or giving the minimum number of voids in concrete.
• The ingredients used in this concrete contains large voids.
• For achieving an impervious or dense concrete then all voids should be packed with smaller particles of the next type of material.

Advantages

Green concrete has the following advantages.

1. It reduces the effect of shrinkage and creep.
2. It uses reused or recycled material in concrete.
3. Flexural and compressive strength is equal to conventional concrete.
4. Its mix design is easier for handling.
5. It requires less repair and maintenance.
6. Reduces the dead weight of the structure.
7. This concrete has good thermal and fire resistance.
8. It reduces environmental pollution.
9. It is economical as compared to conventional concrete.
10. Reduces the overall consumption of cement.

Disadvantages

1. Its compressive strength is less than conventional concrete
2. The effect of creep and shrinkage is more than conventional concrete.
3. Its flexural strength is less than conventional concrete.
4. Water absorption is more than conventional concrete.
5. Life than structure as compared to conventional concrete.

Read also:

1. Difference Between concrete and mortar