Evaluation of the potential of Sasobit® to reduce required heat energy and CO2 emission in the asphalt industry

Warm-mix asphalt (WMA) has been gaining popularity in the asphalt industry primarily because of its ability to lower the energy required to blend asphalt mixes, which in turn results in less fuel consumption, slower aging of the asphalt binder and reduced emission of greenhouse gases. This paper evaluates the effects of different quantities of a WMA additive known as Sasobit (R) on the required heat energy and the amount of CO2 produced to increase the temperature of two aggregates from three sources and one binder from 25 degrees C to the point of mixing. The results showed that incorporating 1% Sasobit (R) can potentially reduce the required heat energy and amount of CO2 produced by 2.8% and 3.0%, respectively, for all aggregate types and sources investigated. The paper also presented design charts that enable energy policy makers and engineers to select the appropriate Sasobit (R) content to produce the most cost effective asphalt mixture with less environmental impact. The design charts show that 1.6% Sasobit (R) content is the most suitable proportion to be blended into the asphalt binder without compromising pavement resistance against fatigue failure. Two similar aggregates from different sources may exhibit similar specific gravities, but their specific heat capacities can vary widely. These differences have a significant effect on the required heat energy, asphalt production cost and the amount of emissions released into the environment. (C) 2010 Elsevier Ltd. All rights reserved.