Restoration Effect of Waste Cooking Oil on the Colloidal Structure of Aged Asphalt

The aging of asphalt is accompanied by alterations in its colloidal structure that in turn leads to premature failure and/or deteriorates the performance of asphalt binders. The use of rejuvenators to restore asphalt binder has received significant attention in recent years, among those waste cooking oil is an abundant and environmentally-friendly asphalt rejuvenator that can restore the physiochemical and rheological performance of aged asphalt. However, the effect of waste cooking oil on the colloidal structure of aged asphalt and the underlying mechanisms of its action are not well understood. This study incorporated molecular simulations and laboratory experiments to study the regeneration mechanisms of waste cooking oil based on the changes in the colloidal structure of asphalt. Results show that waste cooking oil molecules alter intermolecular interactions within the asphalt matrix while mitigating the aggregation process of the larger molecules of the aged asphalt. The latter is also evidenced in the reduction of the size of the aging-induced asphaltene nanoaggregates through the physical space barrier of waste cooking oil. The study outcome promotes resource conservation and sustainability by providing insights pertaining to the regeneration mechanism of asphalt, especially those enabled by waste cooking oil.