What is sustainability in construction and civil engineering?
Sustainability in construction and civil engineering is the optimization of construction activities in a way that does not have harmful effects on resources, surroundings and living ecosystem. It is a way of minimizing harmful environmental impacts of construction projects.
Construction involves activities like use of building materials from various sources, use of machineries, demolition of existing structures, use of green fields, cutting down of tress etc. which can impact environment in one or more ways.
Why is sustainability important in construction?
Construction has a direct impact on the environment due to following reasons:
- Generation of waste materials
- Emissions from vehicles, machineries
- Noise pollution due to use of heavy vehicles and construction machineries.
- Releases of wastes and pollutants into water, ground and atmosphere.
Sustainability assessment of construction projects is essential to the fact that it does not create any harmful effects on the living ecosystem while optimizing the cost of construction. This is to ensure the availability of resources for the future generations. Following are the important construction activities which have large impacts on sustainability in construction and civil engineering:
1. Wastes from demolition of building and structures:
Over billions of tonnes of construction and demolition waste are generated worldwide annually. These wastes can be hazardous to environment is not disposed off at suitable place without environmental impact assessment of such wastes. The other alternate is to recycle and reuse of the demolished building materials to minimize the risk of harmful impacts.
How to make construction waste sustainable?
Following are the steps which need to be followed to make construction waste more sustainable:
- Eliminate – avoid producing construction waste in the first place.
- Reduce – minimize the amount of waste you produce.
- Reuse – reuse the construction wastes in other works.
- Recover (recycling, composting, energy) – recycle what you can only after you have reused it.
- Dispose – dispose of what is left in a responsible way.
Use of durable construction materials and quality control at site for durability of structure is one step towards minimization of construction waste generation.
2. Use of Sustainable Building Materials:
Building Materials such as sand and gravel have been used for thousands of years in construction. The demand for these is increasing day by day as demand for infrastructure development is increasing.
Uses of construction materials such river sand and gravels also have negative impact on environment. Excessive sand-and-gravel mining causes the degradation of rivers. Instream mining lowers the stream bottom, which may lead to bank erosion. This results in the destruction of aquatic and riparian habitat through large changes in the channel morphology. Impacts include bed degradation, bed coarsening, lowered water tables near the streambed, and channel instability.
There are many harmful impacts of using river sand and mining of gravels and a detailed study is required to list all the negative impacts. The use of alternate building materials can reduce the impact of this on environment.
The alternate to river sand is Manufactured Sand (M-Sand) which can be used in construction works reduce impacts of mining river sand.
3. Energy Consumption and Green House:
Around 40% of total energy consumption and greenhouse gas emissions are directly due to construction and operation of buildings. The best of to reduce this impact is the use of green buildings construction techniques. The use of transparent concrete in buildings also helps to reduce the use of energy for lighting during day time.
Fig:Example of a Sustainable Building Construction
How to Ensure Sustainable Construction?
Following steps should be taken to for better sustainability of construction activities:
- Reduce the supply chains to reduce transport costs
- Exercise waste minimization and recycling construction
- Building orientation – Choose the building orientation in a way to reduce energy utilization.
- Durability and quality of building components, generally chosen to last for the appropriate refurbishment or demolition cycle.
- Use construction materials which are locally available.
- Design buildings and structures as per local topological, climatic and community demands.
- Select appropriate construction methods – prefabrication, wood or concrete structures.
- Reuse of existing buildings or structures can reduce the construction waste. Reutilizing by strengthening and rehabilitation of buildings can also save construction cost.
- Make site waste management plans not only during construction but also during use or operation.
- Minimize energy in construction.