Preparation and properties of imidazoline surfactant as additive for warm mix asphalt

Abstract

The high-quality imidazoline surfactant (IMDL) was prepared via amidation of palmitic acid with tetraethylenepentamine followed by intramolecular cyclization reactions as an additive for a warm mix asphalt (WMA). The chemical properties of IMDL and their effects on the performance of asphalt and asphalt mixtures were studied, and the mechanism of its warm mixing effect was discussed. The results show that IMDL molecules contain typical imidazoline functional groups, and IMDL has little effect on the conventional physical properties of asphalt. Particularly, IMDL does not reduce the viscosity of asphalt effectively; Meanwhile, it reduce contact angle of asphalt on aggregate surface which makes it easier for asphalt to spread on aggregate surface and results in a warm mix effect. Thus, IMDL possesses excellent properties that significantly reduce mixing temperature of asphalt mixtures. With the 0.3 wt% addition of IMDL into asphalt, the reduced mixing and compaction temperature of asphalt mixture approaches 31 °C, which effectively cuts the emissions of asphalt fumes by 43.59% and achieves significant energy savings. Furthermore, IMDL can improve the high-temperature performances of asphalt mixtures with little effect on the water stability. Additionally, the price of self-made IMDL can be half of WMA additive widely used in China. In conclusion, IMDL is a good candidate for WMA with high performance and low cost.