Research On Anti-uv Aging Performance Of Modified Asphalt In Qinghai-tibet Plateau

According to the characteristics of ultraviolet radiation on the Qinghai-Tibet Plateau,perennial low temperature extreme climate and huge and rapid temperature difference between day and night,this paper studies the applicability of modified asphalt commonly used in road engineering in the Qinghai-Tibet Plateau.This paper selects three kinds of modified asphalt which were widely used in engineering field,namely SBS modified asphalt,SBR modified asphalt and rubber modified asphalt.The ultraviolet ray aging equipment was used to test the matrix asphalt and the modified asphalt for different degrees of aging.High temperature performance,low temperature performance,fatigue properties and microscopic observation tests of matrix asphalt and modified asphalt with different degrees of aging.This study has the following conclusions: UV aging will affect the high temperature performance of asphalt,making it harder,reducing the low temperature performance and fatigue performance of asphalt;the ability of three modified asphalts to resist UV aging is quite high,and both are much larger than matrix asphalt;The high and low temperature properties and fatigue properties of asphalt are the best among the three modified asphalts.According to the performance of modified asphalt,the modified asphalt types recommended for use in the Qinghai-Tibet Plateau are SBS modified asphalt and rubber modified asphalt.In this study,different doses of hindered amine light stabilizer GW-944 were added to different modified asphalts to explore the effects of light stabilizers on the high and low temperature fatigue properties and UV aging resistance of modified asphalt.The test results show that the addition of hindered amine light stabilizer can effectively enhance the UV aging resistance of the modified asphalt,but it is not recommended for all modified asphalt because it has a detrimental effect on some properties of asphalt;-944 hindered amine light stabilizer,recommended additive of SBS modified asphalt is 0.6%-0.8%,and the recommended dosage of rubber asphalt additive is 0.4%-0.6%.The high temperature performance test of this experiment used the rotational viscosity test and the DSR dynamic shear rheological test to determine the rutting factor index of the rotational viscosity index.The low temperature performance test used the force measurement ductility test and the BBR low temperature bending beam rheological test to determine the The toughness ratio,the creep stiffness modulus and the creep rate m value index;the fatigue performance was measured by the DSR test,and the fatigue factor index was determined;the microscopic observation was performed by fluorescence microscopy,and the phase change of the modified asphalt was observed.