Design And Pavement Performance Test Of Recycled Engine Oil Bottom Rejuvenated Asphalt Mixture

At present,China’s transportation industry alone produces 25 to 30 million tons of recycled engine oil every year.Recycled Engine Oil Bottom(REOB)remains after the regeneration of recycled engine oil can not be effectively recycled due to excessive impurities,and improper treatment can easily lead to serious environmental pollution.In order to realize the reuse of REOB resources,based on the similarity compatibility between REOB and asphalt,the practical feasibility of REOB as asphalt regenerant and its pavement performance for rejuvenated asphalt mixture were studied by relying on the project "Study on the Effect and Mechanism of Recycled Engine Oil Bottom on the Modification Performance of Asphalt"(ZR2016EEM42)of Shandong Natural Science Foundation and the project "Research on Modification Behavior Mechanism of Recycled Engine Oil Bottom on Recycled Asphalt"(J16LA17)of Shandong University Science and Technology Program.Compare the performance and component content of three REOBs(REOB-1,REOB-2 and REOB-3)with the standard regenerant to verify the theoretical feasibility of REOB as a regenerant;The effects of different REOB types and dosages on the physical indexes of indoor simulated aged asphalt were studied and compared to determine the best type and dosage of REOB as regenerant,and the regeneration mechanism was revealed by combining performance and component analysis.The composition design of REOB rejuvenated asphalt mixture with different proportions of simulated aged asphalt mixtures(20%,40% and 60%)was carried out,and the pavement performance of the rejuvenated asphalt mixture was studied to determine the maximum content of the aged asphalt mixtures.The main conclusions are as follows:(1)All three REOBs meet the performance and composition requirements of regenerants in the specification.Only REOB-3 at 7% content can completely rejuvenate aged asphalt.Four-component analysis shows that the mechanism of REOB rejuvenation for aged asphalt is incomplete adjustment of components,and chemical reaction transformation and migration between the four components can not be ignored.The addition of REOB mainly achieves rejuvenation by reducing asphaltene content and increasing resin content of aged asphalt.(2)Penetration diffusion test showed that REOB had insufficient thermal stability at high temperature(170 C);Delayed TFOT ageing test showed that the long-term(TFOT ageing more than 10 h)ageing performance of REOB regenerated asphalt was inferior to that of base asphalt;the addition of REOB enhanced the adhesion of rejuvenated asphalt.(3)The recycled asphalt of simulated aging asphalt mixture is ageing seriously,requiring 5% REOB to achieve rejuvenation;the content of recycled asphalt will reach 3.8% from 4.2%.The optimum new asphalt content of REOB reclaimed asphalt mixture under three kinds(20%,40% and 60%)of old mixtures is 3.4%,2.6% and 1.8% respectively.(4)The high temperature stability of REOB reclaimed asphalt mixture increases with the increase of the content of used asphalt mixture,while the low temperature crack resistance,water stability and long-term aging resistance decrease.After comprehensive comparison of pavement performance,the maximum content of used asphalt mixture can reach 40%.The conclusions prove that REOB can be used in asphalt rejuvenation,which can not only widen the recycling channel of REOB,but also bring huge economic and social benefits to the recycled asphalt pavement technology.