Component Of Waste Cooking Oil Based On Molecular Weight Classification And Its Effect On Performance Of Aging Asphalt

Waste cooking oil contains large amount of organic components such as esters and polycyclic aromatic hydrocarbons,which are similar to the components of asphalt binder and can be used for the regeneration of reclaimed asphalt pavement.However,the rejuvenation effects of waste edible oil are highly dependent on their source and composition,and controlling the variability of waste edible oil is the key to its application in the field of asphalt rejuvenation.For this reason,different components of waste cooking oil were analyzed by GC-MS.This research classified the waste edible oils into three components,i.e.light components,medium components and heavy components,based on their molecular weight.The physical and chemical properties of these components were characterized and their effects on aged asphalt binders and mixtures were also studied.The following conclusions were drawn.(1)The molecular structures of different waste cooking oil components were almost the same,however the molecular weight distribution among these components demonstrated significant difference.The light component(C6-C12)/(C12-C18)is about 1/4,and the above C18 is only 1%;the medium component(C6-C12)/(C12-C18)is about 1/47,and C18 above 3%;the heavy component does not contain the substance below C12,the C12-C18 is 33%,and the C18 is up to 67%.The thermal stabilities of these three components were decreased with increase in molecular weight increase.the viscosity,composition,thermal stability and anti-aging performance of these waste cooking oil components met the standards of asphalt rejuvenator except for the flash point of light components.(2)The addition of different components improved the low temperature plasticity and reduced the high temperature stability of the aged asphalt binders.Under the influence of molecular weight distribution,the optimum dosage of the middle grade road temperature coefficient range is obvious.The anti-fatigue properties,low-temperature rheological properties and the colloid instability index of the aged asphalt binder could recover to the fresh level,and even a better anti-rutting performance could obtain due to the improvement of the colloid structure of the aging asphalt.The results of the four components test were similar to their theoretical values,meanwhile no new functional group appeared during the rejuvenation process,which indicated that no chemical reactions happened between the oil components and the aged asphalt binders.(3)The incorporation of different components of waste edible oil could significantly improve the water stability and low-temperature cracking resistance of the aging asphalt mixture,while the anti-rutting ability was reduced in certain degree.When the content of light,medium and heavy components reached to 9wt.%,9wt.% and 12 wt.% of the aged binder,respectively,the low-temperature performance of the mixture was the optimum.light,medium and heavy components reached to 7wt.%,9wt.% and 12 wt.%,the mixture had a favorable water stability.Besides,the improvement of different components on the low-temperature performance and water stability of the mixture were as good as the total composition oil when its content was 9wt.%.Separating the components of waste edible oil based on the molecular weight in this research provided a new approach to overcome the variability of waste edible oil.the same rejuvenation effects as total composition oil could be achieved by using the separated composition oil.This research is significant to standardize the utilization of waste cooking oil in the field of asphalt regeneration.