The use of warm-mix asphalt (WMA) has received considerable attention in recent years to reduce energy consumption and air emissions. Despite thesepromising benefits, the promotion of WMA based on a single factor such asreduced energy consumption or reduced emissions does not provide a complete evaluation of this technology and may omit critical environmental factors that should be considered in the decision-making process. The objective of this paper was to determine the life-cycle assessment of WMA technology as compared to a conventional hot-mix asphalt mixture. To achieve thisobjective, a life-cycle inventory (LCI) that quantifies the energy, material inputs, and emission during aggregate extraction, asphalt binder production, and hot-mix asphalt production and placement, was developed. Basedon this inventory, life-cycle impact assessment of WMA technology was determined. Based on this analysis, it was determined that WMA provides a reduction of 24% on the air pollution impact of HMA and a reduction of 18% on fossil fuel consumption. Overall, the use of WMA is estimated to providea reduction of 15% on the environment impacts of hot-mix asphalt (HMA). While WMA is expected to improve the hot-mix asphalt production category, it will not have a direct impact on the other three main processes taking place during production of hot-mix asphalt: aggregate production, asphalt binder refinery, and transportation and construction processes. In order to achieve further improvement of the sustainability of HMA production andconstruction activities, it will be necessary to consider additional technologies such as low-emission and fuel-efficient construction equipments and use of reclaimed asphalt pavement.
Abstract