Environmental life cycle assessment and cost analysis of aggregate production industries compared with hybrid scenario

Abstract

Abstract. Aggregates are generally divided into three scenarios, depending on the production methods. The first scenario considers the production of natural aggregates (NA), while the second scenario views the production of recycled aggregates (RA) with construction and demolition (C&D) waste. The third scenario, however, is a hybrid scenario which is the combination of NA and RA, assuming a mixing percentage of 50%. In point of fact, the first scenario is the current policy implemented in many countries, whereas the second and the third scenarios are the proposed alternative options. The present study evaluates the environmental impacts and cost of the production of aggregates via each scenario, in a way that energy consumption, CO 2 emissions and cost are considered as the main variables. The total cost encompasses the costs of investment, energy, and maintenance. To conclude, this research reveals that Iran's current policy with an annual energy consumption of 1.48 million tons of oil equivalent can have a footprint of 2.88 million tons CO2eq emissions per year and cost of 1301 million USD per year (the first scenario). Achieving 30%, 36% and 32% reduction in annual energy consumption, CO 2 emissions and total cost, respectively, by the third scenario compared to the first scenario unravels the destructive effect of the first scenario from environmental and economic perspectives.

Economic and Environmental Evaluation and Optimal Ratio of Natural and Recycled Aggregate Production

“…The basic approach of the majority of countries to aggregates production is based on two mentioned scenarios, in both of which the first phase is based on diesel equipment, and the second phase is based on electric equipment (see Table 1). The energy (diesel and electricity) that is consumed by the plants is called the final energy and is equivalent to energy demand [34,35]. But this energy (final) is a product of an initial source known as the primary energy (e.g., crude oil).…”