Inventory of sand and pebble production for use in hot mix asphalt: A case study in Brazil

Abstract

Life cycle inventory (LCI) data for hot mix asphalt (HMA) concrete pavements is largely missing in Brazil, despite the fact that HMA is the material used in 99% of the Brazilian road network. To overcome this deficiency and carry out life cycle assessment (LCA) studies in this area, Brazilian researchers have continuously resorted to background data based on the international context and hypothetical scenarios. However, these practices have not contributed to environmentally favorable decisions, as little information with national and local representativeness is being incorporated in LCI analyses of asphalt material. This study focused on the collection of primary LCI data for the stages of production of raw materials, manufacturing of asphalt mixture, and construction of a pavement in the context of the Amazon region. Four HMA dosages were studied in a reference (real) and an alternative scenario considering two types of filler: Portland cement and limestone powder. As expected, the stages of production of inputs and manufacturing of the asphalt mixture were the most impactful, representing, in the case study, 98% of the total CO2 emissions and 86% of the embodied energy. The most critical inputs were Portland cement in the production of raw materials, and heavy fuel in the manufacturing of asphalt. The use of light fuel and adoption of preventive maintenance in the plant promoted a reduction of 19% in the environmental impacts of the manufacturing stage. The incorporation of limestone powder in place of Portland cement promoted a decrease of 42% in the total emission of CO2 and embodied energy.