| During the course of production,transportation,paving and use,asphalt will be affected by various factors,which will cause complex aging reaction and affect the service performance and service life of asphalt pavement.Therefore,how to improve the anti-aging performance of asphalt is very important.Aging of Asphalt during service can be divided into thermal oxidative aging and photooxidative aging,Nano-sized Silica has a good shielding effect on UV light,and the low cost and wide range of rubber powder can enhance the thermal oxidation resistance of asphalt.In this paper,Nano-sized Silica and rubber powder and base asphalt were melted and blended to prepare Nano-sized Silica/rubber powder compound modified asphalt,and the effects of compound modifier on physical,rheological,thermal oxidative aging and photooxidative aging properties of asphalt were studied.Aiming at the segregation problem of compound modified asphalt,two modifiers were modified by silane coupling agent KH550.The effect of surface modification and its effect on compound modified asphalt were analyzed.The results of conventional physics and SHRP rheological tests show that Nano-sized Silica can improve the high temperature stability and anti-light oxygen aging properties of asphalt,but it will affect the low temperature performance of asphalt,and the rubber powder has a certain effect on improving the high and low temperature performance of asphalt,and it can also improve resistance to heat and oxygen aging.The performance of compound modified asphalt is better than that of single modified asphalt.The performance test of asphalt before and after thermal oxidative aging is carried out.The test results of TFOT and PAV show consistency.The results show that the residual needle penetration index of the compound modified bitumen increased,the softening point increment,the viscosity aging index,the complex modulus aging index and the stiffness modulus aging index decreased.The compound modifier can improve the thermal oxidative aging properties of asphalt.The performance test of asphalt before and after photo oxidation is carried out.The results show that the modified asphalt has excellent photo-aging resistance.When the amount of compound modifier is 4%Nano-sized Silica+20%rubber powder,the compound modified asphalt has the best anti-aging property.The silane coupling agent KH550 modified Nano-sized Silica and rubber powder,to solve the problem of compatibility of composite modified asphalt.The test results show that the compatibility of the surface modified Nano-sized Silica and rubber powder and asphalt has been greatly improved,the surface modification of compound modified asphalt high temperature performance,anti-aging performance is improved,which has no effect on the asphalt low temperature crack resistance. |
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