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Evaluation of Warm Mix Asphalt Technology for Pavement Rehabilitation


Warm Mix Asphalt (WMA) technology has the capability of lowering the temperature at which the asphalt is mixed and compacted by 30°C or more while also improving the pavement performance. Reduction in production temperature comes with other positive impacts both economically and environmentally. The reduced difference between asphalt mix and ambient temperature results to a lower cooling rate thus a longer timeframe for compaction compared to the conventional Hot Mix Asphalt (HMA). The construction season in Manitoba is limited due to a short period of warm temperatures annually. As a result, owners and contractors have been working towards technologies that will allow paving season to extend towards colder temperatures. Earlier research has shown that the use of WMA technology will allow paved asphalt to achieve compaction at lower mixing and compaction temperatures. The City of Winnipeg awarded a WMA project to a local contractor last year that was used for this study. In addition, a HMA project of the same mix design without additives was used as a reference and loose mixtures were collected to compare both short-term and long-term performances. Three different dosages of 0.3, 0.5 and 0.7 percent of warm mix chemical additive were used. The objective of this project is to perform a field study, laboratory study and case studies to determine the applicability of WMA in typical paving operations and environmental conditions commonly found in Manitoba. The results from Dynamic modulus test suggests WMA mixtures performed significantly better at low temperatures compared to the HMA mixture. However, at higher temperatures the two mix designs performed almost similar. The 0.5 percent additive dosage had a better overall performance especially at lower temperatures. Significant energy saving together with reduction in emission without compromising the pavement performance is expected when using WMA technology. Further investigations on moisture susceptibility and rutting susceptibility are still on going.

Conference Paper Details

Session title:
Innovations in Pavement Management, Engineering and Technologies (S)
Materu, S., Shalaby, A., Ghazy, A., Kibbins, B.