WHAT IS GREEN CONCRETE?
An environmentally friendly concrete,which uses less energy in its production and produces less CO₂ than the normal concrete is called green concrete.
Utilization of fly ash as part of replacement of cement or as mineral admixture in concrete saves on cement and hence the emission of carbon dioxide.
The main objective is sustainable development without destruction of natural resources.
NEED OF GREEN CONCRETE
- The main ingredient in the green concrete is cement and it consists of limestone.
- During manufacturing of cement its ingredients are heated to about 80°c to 1000°c .
- During this process carbon dioxide is released.
- Approximate 1kg of concrete releases about 900gms of CO₂ into the atmosphere.
- Therefore green concrete came into the existence to reduce the emission of CO₂.
It should follow the techniques 3-R technique
- Reduce the greenhouse gas emission.
- Reduce the use of natural resources such as limestone, shale, clay and natural river sand.
- Use of waste material.
The concrete should have the following requirement’s to say it as green concrete.
- Optimum use of available materials.
- Better performance.
- Reduce shrinkage and creep.
- Reduce carbon foot print.
- Enhanced cohesion workability/consistency.
- Durability- better service life concrete.
- No increase in cost.
SUITABILITY OF GREEN CONCRETE IN STRUCTURES
Several factors which enhances the suitability of green concrete in structures includes:
- Reduce the dead load of the structure and reduce the crane age load; allow handling, lifting flexibility with lighter weight.
- Reduction of emission of CO₂ by 30%.
- Increased concrete industries use of waste products by 20%.
- Good thermal and fire resistance, sound insulation than the traditional concrete.
- Improve damping resistance of the building.
- No environmental pollution and sustainable development.
- It requires less maintenance and repairs.
- Compressive strength behaviour of the concrete with water cement ratio is more than that of conventional concrete.
- Flexural strength of the green concrete is almost same as conventional concrete.
The concrete mix for such concrete same as conventional concrete, however the constituent pack in themselves in such a manner that they occupy minimum value or minimum voids in concrete.
MATERIALS FOR GREEN CONCRETE
It is composed of renewable material, rather than natural resources. Depending upon the project goals, green material may involve an evaluation of one or more of the following criteria.
- Locally available.
- Reusable or recyclable.
- Re-fumished, salvaged.
ADVANTAGE OF USING FLY ASH IN CONCRETE
- Utilization of fly ash as part of replacement of cement or as mineral admixture in concrete saves on cement and hence the emission of carbon dioxide.
- Use of good quality of concrete shown remarkable improvement in the durability, especially in
- aggressive environment.
- Higher ultimate strength
- Improved workability
- Increased durability
- Reduced bleeding
- Reduced shrinkage
- Increased resistance to alkali-silica reactivity.
ADVANTAGES OF GREEN CONCRETE
- Optimized mix design mean easier handling, better consistency and easier finishing.
- Reduction in shrinkage and creep
- Green concrete uses local and recycled materials.
- The heat of hydration is technically lower than the traditional concrete.
This results in a lower temperature rise in large concrete pours which is distinct advantage of green concrete.
DISADVANTAGES OF GREEN CONCRETE
- Water absorption is high.
- Structure constructed with green concrete have less life time than structure constructed with conventional concrete.
- By using stainless steel cost of the construction will increase.
- Tension strength of the green concrete is less than that of conventional concrete.
APPLICATION OF GREEN CONCRETE
Following are the major application of green concrete:-
- It is used in construction of bridges.
- It is used in construction of building.
- It can be used in road construction.
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