The building industry has become a source of pollution and large consumption of energy at different levels in various stages of the life-cycle. The great share of the consumption is occupied by the building materials. The article focuses on environment protection and sustainable development by recycling the building materials. Recycling is a fundamental element that diminishes non-sustainable data sources, particularly mining exercises, vitality utilize and transportation costs. Lot of construction waste is generated in the demolishing process and during construction of a building that creates many environment problems when dumped in landfills. By recycling materials, the embodied strength they incorporate is preserved. The power used in the recycling method for most substances is far much less than the power used in the authentic manufacturing. There are many methods to reduce waste and use the recycle material into a building. By recycling the demolished waste or the waste during construction can help in relieving the landfill capacity and also in regaining some energy from the existing building materials which can reduce the embodied energy used in the new building construction. As the manufacturing process for most of the materials can easily incorporate waste products.
This paper will also discuss the integration of waste materials generated in industrial processes or household into usable building materials that lessens the waste stream and will lower the pressure on virgin natural resources.
Keywords: Embodied energy, recycling, waste materials, LCA, building materials
As we all are familiar with the idea that we conserve materials and resources through recycling. If someone throws a piece of paper then he is advised to recycle it as we must ‘save the trees’. This idea suggests that this is the primary reason for recycling to avoid depletion. While some recyclable materials are in abundant supply, it is essential that we recycle.
The major goal for recycling is to save energy and to avoid landfill. There is an embodied energy in every product which is a result of the product’s extraction, production and transportation which is an energy consuming process. By recycling the products, the process of manufacturing of it afresh can be avoided and it will decrease the energy usage.
Waste materials contribute majorly in environment degradation which has become a threat to the environment which has risen the environmental problems. It has become an important factor that these materials should be recycled and then is reused as there is a need of extraction of large quantities of material which leads to the energy consumption and release of pollutants in the atmosphere.
2. Embodied Energy
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the mining and processing of natural resources to manufacturing, transport and product delivery.
And it does not include the building material’s operational and disposal energy.
After extraction of the raw materials, the manufacturing process of goods requires energy input. After manufacturing the product has to be packaged which also requires energy to make. A product which have multiple materials, would have an amalgamation of the embodied energies of its components also.
Embodied energy of some materials:
Aluminium is in abundant supply. It makes up about 8% of the Earth’s crust (by mass). While most of the products have an embodied energy of less than 100MJ, aluminium’s embodied energy is dramatically higher.
Figure 1:Visual representation of the embodied energy of aluminum, glass, plastic, paper, and cement.
Because aluminium is not found in its purest form and has to be processed through various stages for its final use. And it consumes lot of energy. About 3% of the world’s electricity usage is dedicated to aluminium production alone.
It requires very less energy to use recycled aluminium as it only requires cleaning, sorted and some melting in the furnace, which can be powered by natural gas. This process requires very less amount of energy that primary production does.
The important thing to note is that recycling process itself also consumes energy as well. The recyclable material needed to be transported from the recycling plant and to the recycling plant and the energy usage also varies depending on the mode of transportation. Estimates for shipping recyclables 1 km by truck state that 1.82 kJ/kg is necessary 1. By rail, this value drops to 0.41 KJ/ kg 1. By boat, even less energy is needed to transport recyclable goods.
By Reusing the building materials approximately 80%- 90% of embodied energy can be saved that otherwise would have been wasted.
1 Morris, J. (1996). Recycling versus Incineration: An Energy Conservation Analysis. Journal of Hazardous Materials, 47, 277-293. Retrieved from: http://www.ewp.rpi.edu/ artford/~ernesto/F2014/MMEES/Papers/ENVIRONMENT/4SolidWaste/SW-Preprocessing-Separation-Recycling/Morris1996-Recycling-vs-Incineration-Energy.pdf
The savings varies considerably by recycling of various materials, with savings up to 90% for aluminum but only 18% for glass. Also, some reprocessing may use more energy, particularly if long transport distances are involved.
3. Life cycle assessment (LCA)
Life cycle assessment (LCA) analyzes the aggregate natural effect of a material or item through different steps ; each progression of its life — from getting crude materials (e.g. through mining or logging) completely through make, transport to a store, and utilizing it in the home, to transfer or reusing.
Figure 3: Life Cycle assessment
LCA considers an variety of natural effects, for example, depletion of resources, energy and water use, greenhouse emissions, waste generation etc.
It is otherwise called support to grave system as it includes the procedure through its extraction to its transfer as they are breaking down and evaluated. In an entire, the aggregate life cycle of an item is breaking down.
4. Capability of Industrial and Mine Solid Wastes for Building Materials and Products
There has been a great pressure that is put on natural raw material resources as building material consumes in bulk quantities while manufacturing It has turned out to be evitable to search for the substitute like the utilization of industrial/mine waste for the make of building materials.
Table 1:Types of several Inert industrial/mine solid wastes in India (Source: Asokan)
The plants which produce strong waste in mass amounts are extensive scale mining, businesses and warm power plants. The waste that are put away in loads and dams are in a huge number of tons and causes ecological and contamination peril. This waste can be reused and utilized for the development reason. The investigation zone for reuse of reusing material has now widen up and new materials are additionally coming up.
In this part we will examine a portion of the materials that can be another for some high vitality expending material. And furthermore, some new materials produced using the household and industrial waste.
4.1.1. Fly ash
Fly ash remains is a side-effect from consuming coal in control plants. It contains aluminous and siliceous material, a pozzolan substance which makes concrete like item when blended with water.
It can be proficiently blended with concrete and is a decent substitute to replace it with some level of Portland bond along these lines sparing the amount utilized which thus will save the money.
It turns into an environmentally friendly material in the framework as recycling of the waste material is being done and it can be used instead of the cement which takes lot of energy during construction and is also responsible for the release of dust that degrades the environment. And also, it is easily locally available material as it is an industrial waste so it also saves on transportation energy.
The green ratings system has now incorporated a section of using fly ash in cement from 20%- 50% to encourage the use of recycled fly ash according to which they get points according to the usage.
4.1.2. Newspaper wood
Newspaper Wood reverses a traditional production process; not from wood to paper, but from (news)paper to wood.
Newspaper is a common name in everyday household and hardly used for a day or two and after that it is discarded. It is estimated that about 2.7 billion people around the world read newspapers.
The newspaper wood is used in the interiors such as tables, cupboards, etc.
It is made by coating individual sheets of old newspaper with glue and then tightly rolling the glued sheets into logs. The glue used is solvent and plasticizers-free.
There are a few confinements additionally as the boards are constrained in size to the width of an open newspaper so bigger sizes are just accessible as facade. The quality of the material depends on the quality of the paste, which limits utilizing Newspaper Wood as a basic part.
Be that as it may, it can replace the utilization of timber to some degree in the insides and is the best interchange. It must be prepared which will expend vitality yet then again it will likewise stay away from the all the more cutting of trees for making furniture.
4.1.3. Recy blocks
These blocks are produced using old plastic bags. It can be reused as plastic bags are not going to disappearing soon.
It is evaluated that every year a sum of 1 trillion plastic bags are utilized and discarded around the world.
It can take up to 1000 years for them to corrupt. Just around 3 percent are reused. So Recy blocks is an inventive method to utilize the plastic bags into the building structures.
Plastic wrapping material which has been squeezed under heath into a cushion formed square shape component. It is a fascinating square which is made of a wide range of plastic waste material, hued plastic sheets and by including an expansion of an exceptional question produced using plastic (e.g. flowers).
Unique design can be created by using different coloured plastic bags. As it is too lightweight it cannot be used for load bearing walls. The application usage for inside and outside are such as a recy-block wall, sitting elements or just as a remarkable decoration element by itself. It is unknown if it is fire resistant or not but overall it is a good strategy to recycle plastic bags.
4.1.4. Blood bricks
This idea rests on the assumption that animal blood counts as a waste product. This, is a potentially offensive idea – but while carnivores are still munching away, they’re still wasting loads of animal blood, especially in societies without industrialised food production systems. And, as it turns out, blood is one of the strongest bio-adhesives out there, as it contains high levels of protein.
British architecture student Jack Munro proposes using freeze-dried blood (which comes as a powder), mixed with sand to form a paste; this can then be cast as bricks. This could be especially useful in remote communities, where blood from animal slaughter is plentiful, but strong construction materials are thin on the ground.
It’s still in experimental phases. Compression tests show that the bricks, although incredibly tough, still lack the reliable strength needed to build usable structures.
As an old saying “Well planned is half done”. So, we would like to lay emphasis on restricting the cost factor, energy saving factor and it could be used in other requirements. As the energy demand is increasing day by day it has become essential to save so recycling will play an important factor in energy conservation. The aspect has been broadened by utilizing the industrial, mine and household solid wastes in building construction. Most of the items can be recycled and society is innovating and is finding ways to recycle from the dump. It is not necessary that the material used has to be reprocessed for reuse but some materials can be used directly to save the cost.