Study On Aging Mechanism And Properties Of Asphalt Mastic Under Different UV Light Conditions

In order to cope with the aging problem caused by the ultraviolet aging problem to the asphalt pavement in high altitude areas and strong ultraviolet radiation areas,the road pavement performance and the service life are shortened.In this paper,the variation of various properties and the aging mechanism of asphalt cement in the aging process of asphalt cement under different UV light conditions are studied,which provides theoretical basis and reference value for pavement maintenance in high altitude areas and strong ultraviolet radiation areas.Firstly,through the preparation of asphalt cement,three different asphalt cements with a ratio of powder to rubber of 0.8,1.0 and 1.2 were selected and three different asphalt cements were tested under different UV light intensity and UV light time.The short-term aging of three different asphalt cements was carried out by the asphalt film oven test(TFOT).The physical properties of the samples before and after the short-term aging were tested.The physical properties of the three kinds of asphalt cement before and after aging were analyzed.The samples after the short-term aging were placed in a self-made UV environment box to simulate the ultraviolet light test of the asphalt cement under different ultraviolet light conditions.Finally,three kinds of asphalt were determined by dynamic shear rheological test(DSR),bending beam rheology test(BBR),four-component analysis method,water-immersed Marshall test and freeze-thaw split test for asphalt cement samples before and after UV aging.The rheological properties,microscopic properties and road performance of the asphalt cement under different UV light intensity and different UV light duration were analyzed,and the variation law was analyzed by the test results.Finally,the test results were analyzed:after short-term aging,the softening point of asphalt cement samples increased,the ductility,penetration and cone penetration decreased;under different UV light intensity and illumination duration,the aged asphalt The asphaltene content of the rubber increased,the saturated content decreased slowly,the aromatic content and the gum gradually decreased with the aging degree,and the aggregation index(Ic)gradually increased with the aging time and strength;the asphalt rubber compound shear The modulus of cut,rutting factor and aging index increase,the phase angle decreases;the stiffness modulus index(SAI)becomes larger,and the creep rate index(mAI)becomes smaller;the ratio of powder to rubber is between 0.8 and 1.2.As the ratio of powder to rubber increases,the adhesion inside the asphalt cement increases,and the residual stability and freeze-thaw splitting tensile strength also increase.It has been found that with the increase of the amount of mineral powder,the ratio of powder to rubber is in the range of 0.8 to 1.2,and the larger the ratio of powder to rubber is more obvious by UV aging.