Study On Preparation And Aging Resistance Of Asphalt Modified By Inorganic Nanoparticles/Rubber Powder

Waste tires pollute the environment and are difficult to degrade.It is one of the effective means to solve the problem to mix waste rubber powder obtained by crushing and recycling them with asphalt.The prepared rubber powder modified asphalt can improve the road performance of asphalt to a certain extent,but its limited anti-aging performance and poor stability restrict its further application.Inorganic nanoparticles,as a kind of nanomaterial,not only have unique mechanical,thermal and barrier properties,but also can effectively absorb or refract ultraviolet and visible light.Therefore,in this paper,firstly,the accelerated aging test of rubber powder modified asphalt is studied,and the anti-aging performance of asphalt is comprehensively evaluated Then,different kinds and amounts of inorganic nanoparticles,such as Nano-Zn O,Nano-Si O₂,Nano-TiO₂ and rubber powder,were selected to prepare modified asphalt.The physical rheological properties and anti-aging properties of the prepared modified asphalt were evaluated,and the best proportion of inorganic nanoparticles and rubber powder was obtained by comparison.In addition,the interaction principle between inorganic nanoparticles and waste rubber powder was studied by infrared spectroscopy,fluorescence microscopy,atomic force microscopy and thermogravimetric analysis,and the anti-aging mechanism of asphalt modified by nanoparticles and rubber powder was revealed.Get the following conclusions:（1）The accelerated aging test of rubber powder modified asphalt was carried out in laboratory,and it was found that rubber powder modified asphalt was more intolerant to photooxidation aging.Aging improves the high-temperature performance of rubber powder modified asphalt and damages its low-temperature performance.At the same time,aging causes the polar functional groups carbonyl and sulfoxide groups in modified asphalt to increase,and the aging fluorescent structure in rubber powder partially decomposes.（2）By testing the inorganic nanoparticles/rubber powder compound modified asphalt,it is found that compared with the single rubber powder modifier,the compound modifier further reduces the temperature sensitivity of asphalt,and improves the high temperature performance and elastic recovery performance of asphalt,while the low temperature performance decreases with the increase of nanoparticle content.By comparison,it is found that the order of modification effects of different kinds of nanomaterials is nano-TiO₂>nano-Zn O>nano-Si O₂.The order of modification effect under different dosage is 2wt%>3wt%>1wt%>blank sample.（3）Through the indoor accelerated aging test of inorganic nanoparticles/rubber powder compound modified asphalt,it is found that the compound modifier can not only improve the thermal oxidation aging performance of asphalt,but also effectively reduce the radiation aging effect of light on asphalt.Comprehensive comparison shows that 2wt%Nano-TiO₂ and 20 wt%rubber powder can be used to prepare compound modified asphalt with stable performance and excellent anti-aging performance.（4）Through the observation and analysis of the microstructure of the compound modified asphalt,it is found that the incorporation of nanoparticles enhances the interaction between rubber powder and rubber powder and between rubber powder and asphalt,which makes the rubber powder be sheared and dispersed more finely under high-speed shearing and forms a more stable structure in asphalt.The well-dispersed Nano-TiO2 and rubber powder played an anti-aging role together,which weakened the change range of functional groups,fluorescent structure and apparent roughness of the compound modified asphalt after aging.Thermogravimetric analysis shows that the compound modified asphalt has better thermal stability.