Feasibility assessment of palmitamide derived from waste edible oil as a warm mix asphalt additive

The disposal of waste edible oil (WEO) has become a global challenge with both environmental and economic issues. To provide a novel strategy for the refinement recycling of WEO, this work investigated the feasibility of palmitamide derived from WEO as a warm mix asphalt (WMA) additive. The molecular structure and thermodynamic characteristics of palmitamide were first determined. Following, WMA binders with different palmitamide contents were prepared and their temperature sensitivity and rheological properties were evaluated. Additionally, the engineering performance of WMA mixtures was explored and the environmental benefits of WEO-derived palmitamide were assessed using the gas chromatography-mass spectrometry. The results demonstrate that the phase transition temperature of WEO-derived palmitamide is 98.87 degrees C, which shows great potential as a WMA additive. Palmitamide provides asphalt workability suitable for construction at relatively low temperatures through reducing the flow activation energy of asphalt. In addition, the moisture damage resistance and deformation resistance of WMA is also improved due to the hydrophobicity and filling effect of palmitamide, respectively. While it is inevitable that palmitamide slightly weakens the fatigue and low-temperature performance of WMA. Moreover, the application of WEO-derived palmitamide can reduce the volatile organic compounds of asphalt in the mixing stage and compaction stage by 40.3% and 30.8%, respectively. The findings contribute to the sustainable development of road engineering and the circular of waste resources.