Nowadays, construction waste is one of major environmental contaminants. The Increase of building construction entails escalating demolition of buildings in their midlife that made of decent materials such as bricks, cement, steel, stone, and plaster. After demolition, these manufactured materials turn into trash accumulated on the suburbs causing environmental damage and pollution. Furthermore, high-energy consumption in production process of these synthetic materials is another major problem. The building industry is responsible for high level of pollution due to the energy consumed during extraction, processing, and transportation of raw materials, construction, utilization, demolition, and disposal waste.
To reduce environmental risks in construction materials, it is necessary to investigate the life cycle of building materials and their energy consumption. The life cycle of building materials starts from the moment of extraction in nature and ends when it returns to the nature. Therefore, the use of materials that may harm human or environmental health at any phase of their life cycle must be limited. For materials selected in design, it is vital that the designer meticilously consider the use and disposal of the finished product. This requires clearly through examination of raw materials in order to have very low environmental load both in manufacturing and distribution systems to minimize the environmental impacts.
In this paper, the life cycle of construction materials and its impact on environmental pollution for both synthetic and vernacular materials are investigated and analytically compared. Various environmental factors in construction materials’ selction have been studied in previous researches. By investigating different measures included in environmental charts and tables, a comprehensive model by considering all affecting factors is proposed. The proposed model describes the materials’ life cycle assessment. This model is a guide to evaluate, select and use construction materials more sustainably. The proposed model embraces all stages of materials life cycle including extraction, production process, transportation, construction, operation, destruction, and finally returning to the nature or their reuse as secondary materials.
The nature has the central role in this model. Each stage is investigated in depth and main points are described. All construction materials can be evaluated using the proposed cyclic model. The model has the ability of comparing various materials from environmental impact perspective.
By comparing vernacular and synthetic materials regarding environmental factors, it is confirmed that using vernacular materials is more beneficial due to less environmental load. Synthetic materials impose wide variety of burdens on the environment through every step of production, processing, consumption, use, recycling, transportation and disposal. Benefits of using vernacular materials are reduction of pollution in manufacturing process, less energy consumption in transportation, construction, utilization, minimizing embodied energy and embodied carbon, efficient use of resources, reduced costs, and drastically diminished environmental impact of construction.