Research On The Performance Of PU-SBS Composite Modified Asphalt And Its Porous Elastic Mixture

With the rapid development of China’s economy and the sharp increase in the number of motor vehicles,road traffic noise pollution has gradually become a hot social issue.Paving low noise road surfaces can effectively solve this problem.Poroelastic Road Surface(PERS)is currently one of the best low noise road surfaces for noise reduction.However,due to the unique structural composition of porous elastic mixtures(large voids,high rubber particle content),its durability has significant problems,which restricts its practical application.In order to improve the road performance of porous elastic pavement and extend its service life,it is necessary to develop a binder with excellent low-temperature ductility,low temperature sensitivity,and good comprehensive performance.This article uses multiple types of polyurethane(PU)and SBS to composite modify 90 #matrix asphalt.Through performance testing of raw materials,PU-2 and 1201 SBS were ultimately selected as modifiers;The shear temperature and time of PU-SBS composite modified asphalt were determined through Blockfield viscosity test and fluorescence microscope test,and the modification process of PU-SBS composite modified asphalt was finally determined based on relevant literature.It was found that the low-temperature performance of PU-SBS composite modified asphalt mainly depends on PU-2,while the hightemperature performance mainly depends on SBS characteristics.The low temperature ductility,storage stability,viscosity temperature characteristics and anti-aging performance of PU-SBS composite modified asphalt with different content were analyzed by means of three indicators,segregation test,aging test,viscosity test and other test methods.Finally,the best mix scheme of PU-SBS composite modified asphalt was determined as: 15% PU-2+5% 1201SBS;The high-temperature performance of composite modified asphalt was analyzed using dynamic shear rheological(DSR)temperature scanning and frequency scanning tests.The medium temperature fatigue performance of composite modified asphalt was analyzed through DSR linear amplitude scanning test.The low-temperature performance of composite modified asphalt was studied through simply supported beam bending creep(BBR)test.The test results showed that PU-SBS composite modified asphalt has extremely excellent low-temperature performance,At the same time,it has good high-temperature performance and medium temperature fatigue resistance.The functional group changes of PU-SBS composite modified asphalt were analyzed using Fourier transform infrared spectroscopy(FTIR);The fluorescence images of PU-SBS composite modified asphalt in different states were observed using a fluorescence microscope,and the microstructure of the two modifiers under the combined action was analyzed;The micro morphology of different modified asphalts was analyzed by atomic force microscope.The results indicate that PU-2 undergoes a series of chemical reactions with asphalt,generating new functional groups,forming a more stable system and tightly filling the network structure of SBS.PU-2,SBS,and matrix asphalt form a stable structure,and PU-2 and SBS form a complementary effect during the composite modification process,making PU-SBS composite modified asphalt not only have good high and low temperature performance,It also has excellent storage stability.Using a single particle size gradation,porous elastic mixtures were prepared and specimens were formed using PU-SBS composite modified asphalt,TPS modified asphalt,and SBS modified asphalt as binders.The road performance of the composite modified asphalt porous elastic mixture was studied through high-temperature rutting test,low-temperature small beam bending creep test,immersion Marshall test,and freeze-thaw splitting test.The results show that the road performance of PU-SBS composite modified asphalt porous elastic mixture is generally superior to SBS porous elastic mixture,and the low-temperature performance is much better than TPS porous elastic mixture.Finally,the void sound absorption characteristics and vibration and noise reduction performance of porous elastic mixtures were studied using impedance tube testing systems and ultrasonic detectors.The results showed that the sound absorption coefficient of porous elastic mixtures was higher than OGFC-13 and AC-13,indicating good sound absorption performance.Moreover,with the increase of rubber particle content,the elastic modulus of porous elastic mixtures decreased,and the vibration and noise reduction effect increased.