comparative life cycle analysis of low energy-consuming materials, case studies: concrete, brick, wood, system boundary: cradle to gate

Recent researches all across the world emphasize the threat of the increasing consumption of energy. the undeniable role of energy consumption in all stages of the life cycle of materials, including extraction, factory manufacturing, and transportation has revealed the necessity of using sustainable methods to have lower energy consumed. the whole energy of all different steps of the life cycle is called embodied energy and the process of assessing this embodied energy input is called life cycle assessment” (lca). despite the great importance of lca, the quantitative test of such a hypothesis has been less of a concern for previous researchers in our country iran, and due to the lack of organized information from industrial units, such a study has also faced the difficulties of data collection. in this regard, this paper evaluates the amount of embodied energy consumption of building materials at different stages of their life cycle. to reach this goal this research evaluates the initial energy quantitatively (including different stages). more precisely, the present study, based on life cycle assessment system, quantitatively evaluates and compares energy input in different stages of cradle to gate scope, in 3 case studies: concrete, wood, and brick. the results finally show that per ton of concrete produced 110 (kw.h) electrical energy, 35 (ton) of gas, 170 (mj) of human energy, and 495 (g) of gasoline is consumed, while these quantities for per ton of brick are 35(kw.h), 18.2 (ton), 72 (mj) and 250 (g) and for one ton of timber produced are 900 (kw.h), no gas used, 170 (mj) and 495 (g).