Research On Aging Regularity And Test Conditions Of SBS Modified Asphalt And Its Mixture

The aging of asphalt pavement is one of the important factors affecting pavement performance.At present,Thin Film Oven Test(TFOT),Rolling Thin Film Oven Test(RTFOT),Pressure Aging Vessel(PAV)and Short-Term Oven Aging(STOA)are mainly used to study the aging properties of asphalt and asphalt mixture in China.The test conditions of these tests are all based on the production and construction process of ordinary asphalt and are not applicable to SBS modified asphalt.For this reason,relying on the construction project of Gao-Qin(From Gaoping to Qinshui)Expressway in Shanxi Province,The research on the relationship between indoor simulated aging and engineering aging of SBS modified asphalt was carried out to propose a suitable aging test conditions for SB S modified asphalt and asphalt mixture.thereby providing reference for evaluating the aging performance of SBS modified asphalt and technical support for asphalt pavement regeneration technique.1)The short term aging regularity of four kinds of SBS modified asphalt was studied by TFOT test.The results showed that the penetration,ductility and rutting factor of SBS modified asphalt had a good regular relationship with the aging process of asphalt.Considering the experimental error and the applicability of the test,the aging model of SBS modified asphalt was established based on the penetration rate,and the short-term aging test conditions of SBS modified asphalt were caculated in reverse.2)Relying on the support project,the improved recovery test of the SBS asphalt mixture was carried out.The penetration and softening point of the reclaimed asphalt and the asphalt after TFOT test were compared and analyzed.The results showed that the standard TFOT test conditions can not simulate the short-term aging of SBS modified asphalt well,in order to calculate the short-term aging test conditions of SBS modified asphalt,the penetration of reclaimed asphalt were substituted to the aging model,the results showed that the TFOT test at 180 ℃ and 9h can effectively simulate the short-term aging of SBS modified asphalt.3)The aging regularity of three kinds of SBS modified asphalt mixture was studied by STOA test.Six groups of STOA tests were carried out and the penetration of the reclaimed asphalt was determined.The results showed that after 150℃ and 4h STOA test,the penetration of the reclaimed asphalt was very close to that of the asphalt aged during construction.150℃and 4h are recommended as the STOA test conditions of SBS modified asphalt mixtures.4)The correlation between aging of asphalt and climate zoning,PCI,pavement service life and pavement depth is analyzed,and the applicability of PAV test was verified by three groups of PAV tests.The results showed that the standard PAV test can simulate the penetration and softening point loss of natural aging of asphalt pavement in Shanxi province for 13 and 14 years,but the simulation of the ductility loss is not satisfactory.