The built environment accounts for one-third of all carbon dioxide emissions and uses about 40% of the world's total energy output. The rise in carbon emissions is one of the primary causes of global warming and cli87mate change. Now all the nations are coming forward for achieving Net-Zero carbon emissions at Paris agreement. India has reaffirmed its Nationally Determined Contribution to achieve long term goal of reaching net-zero by 2070. By contributing more than 5% to Gross Domestic Product (GDP) of India, the building industry has indeed made a substantial contribution. In India, the building industry is the sole sector responsible for 24% of all sectors' CO2 emissions. The reduction of targeted GHG emissions in India is the main objective of the Climate Change Bill-2012 (India). Additionally, it promises to offer carbon trading and budgeting systems.
Carbon emissions refer to the amount of carbon dioxide and other carbon compounds released into the atmosphere. Buildings are a significant contributor to carbon emissions, as they often require a lot of energy for heating, cooling, lighting, and other functions. There are many ways to reduce the carbon emissions associated with buildings, such as improving energy efficiency, using renewable energy sources, and incorporating sustainable design practices. In many developed countries, such as the US, Australia and Singapore, there is growing recognition for using sustainable construction strategies to reduce environmental impacts (Luo et al. 2022). Usage of sustainable building materials is one of the important factors to reduce GHG emissions. Since the earliest civilisations, the traditional brick has been widely adopted for use in construction. Due to its affordability, conventional brick is in high demand in today's rapidly growing construction industry. However, conventional bricks have an embodied energy of roughly 2.0 kWh. Regarding the elements that make up pollution, a conventional brick emits 0.41 kg of carbon dioxide per brick (Reddy and Jagadish n.d.). To improve the environmental performance of the bricks, it is mandatory to assess the entire life cycle of the material associated with the environmental impacts.
Using conventional bricks and bricks infused with biosolids,(Mohajerani et al. 2018) conducted LCA tests to analyse the environmental effects of each type of brick. To reduce the limited brick soil, the amount of biosolids by dry weight was altered. The comparative analysis revealed that bricks infused with biosolids exhibited a reduced environmental impact. Furthermore, these biosolids-infused bricks exhibited lower embodied energy compared to conventional bricks that did not contain any biosolids.(Parrish and Chester 2014) cited that Life cycle assessment gives important details on the effects on environment and different methods to decrease them. The Life Cycle Assessment (LCA) of a building reveals a number of environmental impacts. The LCA on a project can be performed even before construction starts to evaluate the environmental consequences, giving the contractor the chance to decrease the effects by selecting alternative materials for construction (Pamu et al. 2022). The advantage of LCA is that it analyses the contributions made at each stage of the life cycle of a product, from the acquisition of raw materials to disposal at the end of its useful life. Combining this information not only provides a summary of the product's overall environmental impact, but it can also provide a road map for prioritising efforts to mitigate those effects. Life cycle assessment practitioners frequently employ the pre-defined impact assessment methods provided by the LCA software package (Pamu and Alugubelli 2023).
(Means and Guggemos 2015) utilised focus groups comments to compare the existing LCA tools and approaches with a prepared framework. Gaps when developing an LCA-based environmental decision-making tool were discovered following a comparison of LCA-based environmental decision making for commercial buildings. The databases used in the Life cycle assessment calculations are very important as they play a very important role in the analysis. (Azari and Palomera-Arias n.d.) came to the conclusion that the Athena impact estimator, a tool for LCA, had relatively little data on building materials. (Martínez-Rocamora et al. 2016) collected information from 10 different databases and discovered that relatively few of them provide information on building materials. The study also showed that the GaBi and Ecoinvent databases are more reliable.(Emami et al. 2019) revealed from his studies that accurate information is very much important from the construction industry for decision making using the Life cycle assessment tools.
This study focuses on the Life Cycle Assessment (LCA) of an institutional building using Building Information Modeling (BIM) and OpenLCA software which is widely used in many parts of the world. Eco-invent database is used for the product information in this study to perform LCA. The combination of the Open-LCA software and the eco-invent database is expected to yield superior outcomes compared to other software-database combinations. The selection of the Open-LCA software was driven by its cost-free nature and its potential to deliver improved environmental impact results in the construction sector. Combination of OpenLCA software and BIM will help builders and owners to assess the environmental activities of building. Prior to commencing construction activities, conducting an LCA study enables contractors to assess the environmental consequences arising from building materials. By opting for alternative construction materials with reduced environmental impacts, it becomes possible to mitigate the overall effects.
1.1 Materials used in construction
Cement, bricks, sand (fine aggregate), gravel (coarse aggregate), steel and water are the main building materials. These materials are all limited, and over usage of them will have a negative influence on the ecosystem. Fired clay bricks have greater negative environmental impacts because of scarce clay used in its production and firing process which emits harmful gases into the environment.
1.2 Fired clay bricks
According to estimates, 250 billion bricks are produced in India annually, making it the second-largest brick producer in the world. With the 6.6% annual growth rate, there will be increased demand for building materials, particularly bricks. Burnt red clay bricks have a risk of causing land degradation because they require fertile soil, good-textured, silty, clayey soil in order to produce good quality bricks. The land becomes unproductive when the fertile top soil is removed. Research conducted by(Gupta and Narayan 2010) stated that removal of top soil for preparation of bricks resulted in reduction of manganese and zinc was approximately 35% and 63%. In addition to this, the loss of 28 kg of nitrogen, 3 kg of phosphorous and 34 kg of potash per hectare of land. In addition to degradation of land, burning clay bricks releases toxic gases into the air which are released while production of bricks. It is estimated that Indian brick Industry liberates 80.7 kg of CO2 per thousand bricks due to firing of coal as fuel for the brick manufacturing (Paul Levi and Raut 2021).
1.3 Fly ash bricks
Due to their eco-friendliness and potential qualities, fly ash bricks, a sustainable substitute for conventional clay bricks, have attracted a lot of interest these days. These bricks, which are produced from fly ash, a by - product of coal combustion, reduce waste while also providing other benefits. According to research, fly ash bricks have high strength and durability, which makes them appropriate for use in a various construction application. According to a recent report by the Central Electricity Authority (CEA), coal-based power plants contribute roughly 57% of the total amount of power generated in India (Central Electricity Authority CEA ANNUAL REPORT 2021-22 CENTRAL ELECTRICITY AUTHORITY MINISTRY OF POWER GOVERNMENT OF INDIA n.d.). 167 thermal power plants using coal or lignite are currently operational in India, consuming over 625 million tonnes of coal, or almost three-fourths of the nation's total coal consumption. Because of this, a significant amount of fly ash is being produced, amounting to over 196 million tonnes in 2017–2018.