Study On Rheological Properties Of High Viscous Bitumen Under Different Aging Conditions

With the continuous advancement of sponge city construction in China,high-viscos-ity asphalt is widely used in drainage pavement.The drainage pavement is a porous struc-ture,which is prone to aging due to environmental factors,resulting in cracking,loosen-ing and other damage to the pavement.In this paper,two high-viscosity modifiers,HVA and SINOTPS,were selected to carry out short-term thermal oxygen aging,long-term thermal oxygen aging and ultraviolet aging tests on high-viscosity bitumen,and the phys-ical,high-low temperature rheological properties of high-viscosity bitumen under differ-ent aging conditions were studied through viscosity test,dynamic shear rheological test and bending beam rheological test,and the microstructure of high-viscosity bitumen was identified with fluorescence microscopy and infrared spectroscopy,and high-temperature rheological indexes and functional groups were correlated.（1）Through the three major indicators test of asphalt and the dynamic viscosity test at 60°C,the optimal HVA content was determined to be 12%;SINOTPS high viscosity bitumen content ratio:88:12（i.e.13.6%content）.（2）In thermal oxygen aging,the viscosity test showed that the viscosity aging index was sorted as follows:matrix bitumen>HVA high-viscosity bitumen>SINOTPS high-viscosity bitumen;Dynamic shear rheological tests showed that the complex modulus,phase angle and rutting resistance factors of bitumen were affected by thermal oxygen aging in order:matrix bitumen>SINOTPS high-viscosity bitumen>HVA high-viscosity bitumen,short-term aging improved the resistance to deformation of HVA and SINOTPS high-viscosity bitumen,while long-term aging improved the resistance to deformation of SINOTPS high-viscosity bitumen and reduced the resistance to deformation of HVA high-viscosity bitumen.Low-temperature rheological tests show that the low-temperature per-formance of HVA high-viscosity bitumen is better than that of SINOTPS high-viscosity bitumen.（3）In ultraviolet aging,the viscosity test showed that SINOTPS high-viscosity bitu-men had a larger viscosity aging index,faster aging response speed,greater activation energy increase and reduced fluidity compared with HVA high-viscosity bitumen.Dy-namic shear rheological tests showed that the complex modulus,phase angle and rutting resistance factors of bitumen were ordered by the influence of ultraviolet aging:SI-NOTPS high-viscosity bitumen>HVA high-viscosity bitumen>matrix bitumen,HVA high-viscosity bitumen had better resistance to deformation than SINOTPS high-viscosity bitumen.Low temperature rheological tests show that HVA high viscosity bitumen has better low temperature performance than SINOTPS high viscosity bitumen.（4）The microstructure of highly viscous bitumen under different aging conditions was characterized by fluorescence microscopy and infrared spectroscopy,and the results showed that the degree of polymer degradation was small and the aging degree was low in short-term aging.After long-term aging,the dispersion of high-viscosity bitumen is seriously damaged,indicating that long-term aging plays a major role in the influence of high-viscosity bitumen.In hot oxygen aging,the sulfoxide-based index increased with aging,while the butadiene index decreased,and the aging performance of SINOTPS high-viscosity bitumen was stronger than that of HVA high-viscosity bitumen.In this UV aging,the polymer decreases with aging.The sum of sulfoxide index,carbonyl index,sulfoxide group and carbonyl index increased with aging,while butadiene index decreased,and the UV aging resistance of HVA high-viscosity bitumen was slightly stronger than that of SINOTPS high-viscosity bitumen.（5）The grey correlation method was used to correlate the high-temperature rheolog-ical index and the functional group index.In short-term thermal oxygen aging,the buta-diene index of HVA high-viscosity bitumen had a high correlation with the non-recover-able creep flexibility(J_nr3200),the butadiene index of SINOTPS high-viscosity bitumen had a high correlation with the rutting factor fitting parameter"b",and the sulfoxide-based index of HVA and SINOTPS high-viscosity bitumen had the highest correlation with the strain recovery rate(R₃₂₀₀).In UV aging,the butadiene and sulfoxide indices of HVA high-viscosity bitumen had a high correlation with strain recovery rate(R₃₂₀₀),and the butadiene and sulfoxide-based indices of SINOTPS high-viscosity bitumen had high correlation with non-recoverable creep flexibility(J_nr3200).