Green Concrete
Introduction
Green Concrete is the revolutionary topic in the history of concrete industry, this was first invented in Denmark in year 1998.Green concrete has nothing to do with colour. Green concrete is the type of concrete which is much like the conventional concrete but the production of such concrete require minimum amount of energy and causes least harm to environment. It is a concept of using eco-friendly materials in concrete, to make the system more sustainable. Green concrete is very often and also cheap to produce, because for example, waste products are used as a partial substitute for cement, charges. The size of construction industry all over the world is growing at faster rate. The huge construction growth boosts demand for construction materials. Aggregates are the main constituent of concrete. Due to continuously mining the availability of aggregates has emerged problems in recent times. To overcome this problem, there is need to find replacement to some extent. Nowadays, there is a solution to some extent and the solution is known as “Green Concrete”. It is a concept of thinking environment into concrete considering every aspect from raw materials manufacture over mix design to structural design, construction, and service life.
What is Green Concrete
Concrete which is made from concrete wastes that are eco-friendly are called as “Green concrete”. Concrete that uses less in energy in its production and produces less carbon dioxide than normal concrete is 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. This was first invented in Denmark in the year 1998 by Dr. WG. Concrete wastes like slag, power plant wastes, recycled concrete, mining and quarrying wastes, waste glass, incinerator residue, red mud, burnt clay, sawdust, combustor ash and foundry sand. Green Concrete is a term given to a concrete that has had extra steps taken in the mix design and placement to insure a sustainable structure and a long life cycle with a low maintenance surface. e.g. Energy saving, CO2 emissions, waste water. The goal of the Centre for Green Concrete is to reduce the environmental impact of concrete. To enable this, new technology is developed. The technology considers all phases of a concrete construction’s life cycle, i.e. structural design, specification, manufacturing and maintenance.
Material used in Green Concrete
Need of Green Concrete
Cement-based materials are the most abundant manufactured materials in the world. Today’s exciting trend is the Green building is in our country. The potential environmental benefit to society of being able to build with green concrete is huge. Green Concrete as the name suggests is eco friendly and saves the environment by using waste products generated by industries in various forms like rice husk ash, micro silica, etc to make resource-saving concrete structures. Use of green concrete helps in saving energy, emissions, waste water Green concrete is very often also cheap to produce as it uses waste products directly as a partial substitute for cement, thus saving energy consumption in production of per unit of cement.
Green concrete has greater strength and durability than the normal concrete. It is realistic to assume that the technology can be developed, which can reduce the CO2 emission related to concrete production. Generally the construction industry accounts for a massive environmental impact due to its high demand of energy. As a result of the awareness built during the past few years about green house effect and damage to the nature, more people and countries became conscious about their future.
Green concrete capable for sustainable development is characterized by application of industrial wastes to reduce consumption of natural resources and energy and pollution of the environment. Marble sludge powder can be used as filler and helps to reduce the total voids content in concrete. Natural sand in many parts of the country is not graded properly and has excessive silt on other hand quarry rock dust does not contain silt or organic impurities and can be produced to meet desired gradation and fineness as per requirement. Consequently, this contributes to improve the strength of concrete. An attempt has been made to durability studies on green concrete compared with the natural sand concrete by usage of quarry rock dust and marble sludge powder as hundred percent substitutes for natural sand in concrete. Recent focus on climate change and the impact of greenhouse gas emissions on our environment has caused many to focus on CO2 emissions as the most critical environmental impact indicator.
Environmental Benefits to using Green Concrete
Lasts Longer: Green concrete gains strength faster and has a lower rate of shrinkage than concrete made only from Portland Cement. Structures built using green concrete have a better chance of surviving a fire, as it can withstand temperatures of up to 2400°F. It also has a greater resistance to corrosion, which is important with the effect pollution has had on the environment. Acid rain greatly reduces the longevity of traditional building materials. All of those factors add up to a building that will last much longer than one made with ordinary concrete. Similar concrete mixtures have been found in ancient Roman structures. This material was also used in the Ukraine in the 1950s and 1960s. Over 40 years later, those Ukrainian buildings are still standing. If buildings are not constantly having to be rebuilt, fewer construction materials are needed. The impact on the environment is reduced.
Reduces Energy Consumption: If you use less Portland cement and more fly ash when mixing concrete, then you will use less energy. The materials that are used in Portland cement require huge amounts of coal or natural gas to heat. Fly ash already exists as a byproduct of another industrial process, so you are not expending much more energy to use it to create green concrete. Another way that green concrete reduces energy consumption is that a building constructed from it is more resistant to temperature changes, thus saving heating and cooling costs.
Reduces Carbon Dioxide Emissions : Among the main ingredients in ordinary cement are pulverized limestone, clay, and sand which are heated to a high temperature. This process is responsible for between 5and 8% of all Carbon Dioxide emissions worldwide. The manufacturing of green concrete releases up to 80% fewer Carbon Dioxide emissions. As a part of a global effort to reduce emissions, switching completely to green concrete for construction will help considerably.
Application of Green Concrete
- It is used in the construction of bridges
- It is widely used in the building Construction
- It is used in the construction of Column
- It can be used in the road Construction
Advantages of Green Concrete
- Much change is not required for the preparation of green concrete compared to conventional concrete.
- Reduces environmental pollution
- Have good thermal and acid resistance.
- Compressive and split tensile strength is better with some materials compared to conventional concrete.
- Reduces the consumption of cement overall.
- Green concrete is economical compared to conventional concrete.
- Green concrete having better workability than conventional concrete.
Disadvantages of green concrete
- Structures constructed with green concrete have comparatively less
- Life than structures with conventional concrete
- Compressive strength and other characteristics are less compared to conventional concrete
- Water absorption is high.
Conclusion
- There is significant potential in waste materials to produce green concrete.
- The replacement of traditional ingredients of concrete by waste materials and by products gives an opportunity to manufacture economical and environment friendly concrete.
- Partial replacement of ingredients by using waste materials and admixtures shows better compressive and tensile strength, improved sulphate resistance, decreased permeability and improved workability.
- The cost per unit volume of concrete with waste materials like quarry dust is lower than the corresponding control concrete mixes.
- A detail life cycle analysis of green concrete by considering various parameters is very much necessary to understand the resultant concrete properties
Scope of green concrete in India
“Green concrete” is a revolutionary topic in the history of concrete industry. As green concrete is made with concrete waste it does take more time to come in India because of industries having problem to dispose waste and it also reduces environmental impact with reduction in Co2 emission. Use of green concrete can help us reduce a lots of wastage of several products.