Study On Color Durability And Road Performance Of Colored Asphalt

In recent years,due to its unique color advantages,colored asphalt has been vigorously promoted and applied in urban roads.However,after two or three years of use,the color of most colored pavements will fade and dim to varying degrees.Based on the self-made colored asphalt,this paper mainly discusses the color changes of colored asphalt under different aging conditions,color changes of colored mixture under tire load and rolling,and analyzes the changes of functional groups before and after aging,adhesion between colored asphalt and aggregate,gradation design and conventional road performance of colored mixture.Firstly,by setting up eight groups of raw materials with different proportions,the results of penetration,ductility,softening point,short-term aging and long-term aging properties were obtained.Combined with the current recommended specifications,the optimal proportion of the colored asphalt materials（base oil,resin,polymer,decolorizer and pigment）in this paper was 58∶42∶2∶6∶7;Fourier transform infrared spectroscopy（FTIR）was used to test the original,short-term aging and long-term aging samples of colored asphalt.It was found that the absorption peaks of hydroxyl group and sulfoxide group changed obviously,and the aging of colored asphalt was still dominated by thermal oxygen aging;The color difference meter was used to test the colored asphalt after short-term aging,long-term aging and ultraviolet aging,and the color change value（35）E was calculated.The results showed that the color change range of colored asphalt after short-term aging was small,but the color"enhanced"effect appeared.The long-term aging and ultraviolet aging had a great impact on the lightness of colored asphalt,Especially the ultraviolet aging,because the ultraviolet intensity of indoor laboratory is stronger than that of the outside,under the ultraviolet radiation equivalent to two years of outdoor,the color of colored asphalt darkens obviously and forms a layer of hard material on the surface.Secondly,the adhesion test of colored asphalt and aggregate is carried out.Based on the surface free energy theory and contact angle tester,the surface energy parameters of colored asphalt and basalt aggregate are calculated.The results show that:in the results of cohesion work（35）G,adhesion workW_as and compatibility CR,green asphalt>yellow asphalt>blue asphalt>red asphalt>colorless asphalt,The results of peeling workW_asw shows that the difference of colored asphalt is not significant,and it is concluded that the water stability of the colored asphalt has been improved due to the addition of pigment.Finally,the color change of colored mixture under different rolling times was evaluated by simulating the load of rutting instrument tire.A group of rutting samples with color fixing agent were set for color contrast,and the L,a,b values and（35）E changes of color samples under different rolling times were obtained.The results show that the color change of colored mixture can be slowed down by adding color fixing agent;The results show that the change of blue specimen（35）E is the largest in 1000-15000rolling times,the change of yellow specimen（35）E is the smallest in 1000-3000 rolling times,and the change of red specimen（35）E is the smallest in 7000-15000 rolling times.The Yellow specimen has good color retention.The color value of red specimen changes well in high rolling times,while the color value of blue specimen changes from low rolling times to high rolling times,It is recommended that red and yellow binders should be preferred in actual use to obtain better color durability.