During the past three years, Warm Mix Asphalt (WMA) technologies from European countries have entered the North American market. European experiences with WMA technologies have indicated a significant reduction in mixturetemperature, mixture viscosity, energy consumption and environmental emissions during asphalt mix production and placement in comparison with traditional hot mix asphalt (HMA). Based on North America experiences to date with these technologies, transportation agencies and HMA producers are unlikely to adopt WMA technologies solely for the reduction in manufacturing energy costs and environmental emissions, as these benefits do not cover the associated increase in investment and additive costs of WMA over HMA even in the most expensive North American energy markets. This paper presentsan evaluation of the economic, environmental and mixture performance in order to assess the sustainability of WMA in North America. The paper examines the benefits, risks, investment and material costs, and sustainabilityassociated with the different WMA technologies and specifically the Double Barrel® Green process. Included is an economic and mixture performance evaluation of WMA mixes containing reclaimed asphalt pavement (RAP) and manufactured shingle modifier (MSM) produced with the Double Barrel® Green process during field trials in Vancouver, British Columbia.
Abstract