ECO- concrete


  eco-concrete.rtf (Size: 30.98 KB / Downloads: 1)


INTRODUCTION

ECO- concrete is a revolutionary topic in the history of concrete industry. This was first invented in Denmark in the year 1998. ECO- concrete has nothing to do with color. It is a concept of thinking environment into concrete considering every aspect from raw materials manufacture over mixture design to structural design,construction, and service life.
ECO- concrete is very often also cheap to produce because, for example, waste products are used as a partial substitute for cement, charges for the disposal of waste are avoided, energy consumption in production is lower, and durability is greater. ECO- concrete is a type of concrete which resembles the conventional concrete but the production or usage of such concrete requires minimum amount of energy and causes least harm to the environment.
The CO2 emission related to concrete production, inclusive of cement production, is between 0.1 and 0.2T per tonne of produced concrete. However, since the total amount of concrete produced is so vast the absolute figures for the environmental impact are quite significant.
Since concrete is the second most consumed entity after water it accounts for around 5% of the world use total CO2 emission .The solution to this environmental problem is not to substitute concrete for other materials but to reduce the environmental impact of concrete and cement.
The potential environmental benefit to society of being able to build with ECO-concrete is huge. It is realistic to assume that technology can be developed, which can halve the CO2 emission related to concrete production. With the large consumption of concrete this will potentially reduce the world use total CO2 emission by 1.5-2%. Concrete can also be the solution to environmental problems other than those related to CO2 emission.
It may be possible to use residual products from other industries in the concrete production while still maintaining a high concrete quality thus there is a large potential in investigating the possible use of these for concrete production. Well-known residual products such as silica fume and fly ash may be mentioned.

Environmental Goals :

ECO- Concrete is expected to fulfill the following environmental obligations:
. Reduction of CO2 emissions by 21 %. This is in accordance with the KyotoProtocol of 1997.
.Increase the use of inorganic residual products from industries other than the concrete industry by approx 20%.
.The recycling capacity of the ECO- concrete must not be less compared to existing concrete types.
.The production and the use of ECO- concrete must not deteriorate the working environment.
.The structures do not impose much harm to the environment during their service life.
.Reduce the use of fossil fuels by increasing the use of waste derived fuels in the cement industry.

GENESIS

Considering the time elapsed since the commencement of the use of concrete, Eco-concrete is very young a material. It was invented in 1998 in Denmark. The increasing awareness and activity to conserve the environment and the realization that concrete production too releases a considerable amount of CO2 in the atmosphere were strong initiatives to catalyze the genesis of ECO- Concrete.

In 1997, the Kyoto Conference took place, in which several countries laid down several guidelines which would be the directive principles to the participating countries on their environment related practices. The guidelines( Kyoto Protocol)needed the countries to cut down their CO2 emissions to a certain degree as assigned. The given goal has to be achieved by the year 2012. Since then several countries started to focus on several available options but Denmark focused on cement and concrete production because approximately 2% of its total co2 emission stems from cement and concrete production.

Realizing the necessity of such a technology and the prospects associated, the Danish government soon released a proposal. The proposal covers the following environmental aspects: Greenhouse effect, Depletion of the ozone layer,Photochemical oxidation, Eutrophication, Acidification, Materials harmful to the environment and health, Water and resources. Five environmental impacts given highest priority are:
.CO2
.Energy
.Water
.Waste
.Pollutants
These, coupled with the cost reduction benefits allured the concrete producers to incorporate ECO-concrete into their paradigm.
Cement and concrete may have an important role to play in enabling the urban countries to fulfill their obligation to reduce the total CO2 emission by 21 % compared to the 1990-level before 2012, as agreed at the Kyoto conference. This is because the volume of concrete consumption is large Approx. 1 m3 of concrete per capita are produced annually globally
The some what soft demands in the form of environmental obligations result in rather specific technical requirements for the industry - including the concrete industry.
These technical requirements include among others new concrete mix designs, new raw materials, and new knowledge (practical experience and technical models) about the properties of the new raw materials and concrete mix designs.
On what measurement basis can engineers and architects compare material sand choose one that is more sustainable or specify a material in such a way as to minimize environmental impact?
Life Cycle Assessment ( LCA) seems to offer a solution. LCA considers materials over the course of their entire life cycle including material extraction,manufacturing, construction, operations, and finally reuse/recycling.
LCA takes into account a full range of environmental impact indicators²including embodied energy, air and water pollution (including greenhouse gases), potable water consumption, solid waste and recycled content just to name a few.
Building rating systems such as LEED and Green Globes are in various stages of incorporating LCA so that they can help engineers and architects select materials based on their environmental performance or specify materials in such a way as to minimize environmental impact.
Every 1 ton of cement produced leads to about 0.9 tons of CO2 emissions and a typical cubic yard (0.7643 m3) of concrete contains about 10% by weight of cement.

ADVANTAGES OF ECO-CONCRETE
ECO-concrete has manifold advantages over the conventional concrete. Since it uses the recycled aggregates and materials, it reduces the extra load in landfills and mitigates the wastage of aggregates. Thus, the net CO2 emissions are reduced. The reuse of materials also contributes intensively to economy. Since the waste materials like aggregates from a nearby area and fly ash from a nearby power plant are not much expensive and also transport costs are minimal.
ECO-concrete can be considered elemental to sustainable development since it is eco-friendly itself. ECO-concrete is being widely used in green building practices.It also helps the green buildings achieve LEED and Golden Globe certifications.
Use of fly ash in the concrete also increases its workability and many other properties like durability to an appreciable extent. One of the practices to manufacture ECO-concrete involves reduction of amount cement in the mix, this practice helps in reducing the consumption of cement overall. The use waste materials also solve the problem of disposing the excessive amount industrial wastes.
There are several other advantages related to ECO-concrete and can be summarized as below: