Comparison Of Performances Of Warm Mix Asphalt With Differents Additives

Warm mix asphalt (WMA) is a new technology which has been developed since 1990s. It aims to decrease energy consumption and CO2 and other gases and dust emissions during production process by reducing the mixing and compaction temperatures of asphalt mixture, while ensuring the same performance and construction.workability as Hot mix asphalt (HMA).There are several ways to realize WMA, one of which is using additives. This paper describes the modification mechanism of three kinds of additives, Sasobit, Aspha-min, and SEAM, and proposes a variety of WMA laboratory preparation process.With an AC-20 HMA as control, the volume of asphalt mixture, high temperature stability, moisture stability, low temperature cracking resistance and other important performances and design parameters of WMA with Sasobit, Aspha-min and SEAM additives were evaluated through laboratory tests under the same condition. Results of tests indicate that compared to HMA, the mixing and compaction temperature of WMA decrease 20℃,with improving the high temperature stability substantially and their low temperature cracking resistance is also improved; So, the WMA are remarkable economical and social benefits. However, due to lowering mixing and compaction temperature, the possibility of potential water damage of asphalt mixture is likely to increase, while Sasobit WMA indicates little change in moisture stability, but both Aspha-min WMA and SEAM WMA indicate a decrease in moisture stability. It can improve moisture stability of WMA by adding anti-stripping agents. The resilient modulus vary from 2500MPa to 3000MPa and from 2000MPa to 2400MPa at 15℃and 20℃, respectively.Additive content has a certain influence on asphalt mixture performance. Through the WMA Performance tests Study with different contents of Sasobit, Aspha-min, we found that WMA can be keep the same performance as HMA with Sasobit content at 3%±1%, Aspha-min content at 3‰±1‰.