Evaluation of the Potential of Sasobit REDUX Additive to Lower Warm-Mix Asphalt Production Temperature.

Environmental and health concerns have been increasing in the road construction industry. This industry has provided several techniques and a wide range of additives to lower the production temperatures of asphalt mixtures, generating, among others, a new mix type called warm-mix asphalt (WMA). This paper aims to evaluate the potential of the Sasobit REDUX additive to lower the production temperatures of WMA. This additive, which is an alternative to the well-known Sasobit, is completely soluble in bitumen at temperatures above 85 °C while the same temperature for the Sasobit is 115 °C. For that reason, three target compaction temperatures were considered (90, 100 and 110 °C) and both Marshall and compactability tests were carried out. A hot-mix asphalt (HMA) was tested in parallel for comparison. It was concluded that the volumetric properties (air voids content about 4%) and the Marshall properties (stability about 11 kN, flow about 4 mm and Marshall quotient higher than 2 kN/km) of the Sasobit REDUX-WMA were globally satisfactory. In relation to the compactability test, the Sasobit REDUX-WMA mixtures were relatively easier to be compacted compared to the HMA mixture. The three Sasobit REDUX-WMA mixtures (90, 100 and 110 °C) exhibited a very similar compactability (differences lower than 0.4%). Therefore, it seems reasonable to conclude that the Sasobit REDUX has potential to lower WMA production temperatures by 20 °C. A reduction of that magnitude would lead to significant environmental gains.