Research On Road Performance And Microscopic Mechanism Of Asphalt Modified By Waste Rubber Powder Activated By Vegetable Oil

With the rapid development of the automobile industry,the number of waste tires has increased significantly,and recycling them is an effective way to alleviate environmental problems.At present,waste rubber powder modified asphalt technology has been widely used in road engineering.Waste rubber powder modified asphalt has many advantages,including improving high and low temperature performance,improving durability,saving resources,and reducing pollution.However,due to the existence of the internal vulcanization structure of the rubber powder,the viscosity of the modified asphalt is generally higher and the storage stability is also poor.Therefore,this article uses vegetable oil to activate rubber powder in order to reduce viscosity,improve storage stability,and expand its application in road engineering.This paper selects soybean oil,rapeseed oil and fried waste soybean oil three vegetable oils to activate waste rubber powder,and prepare activated waste rubber powder modified asphalt.According to the performance test results of modified asphalt,the respective activation processes of the three vegetable oils are determined:all three vegetable oils are treated at room temperature to activate the rubber powder;the recommended activation time for soybean oil is 48h,and the ratio of rubber to oil is 3:1;the recommended activation time for rapeseed oil is 72h,and the glue-to-oil ratio is 3:1,the recommended activation time for frying waste oil is 72h,and the glue-to-oil ratio is 3:1.Secondly,the vegetable oil activated waste rubber powder modified asphalt and the ordinary waste rubber powder modified asphalt with different rubber powder content were subjected to conventional performance tests and rheological performance tests respectively.The results show that,compared with the modified asphalt without activation treatment,the viscosity of the vegetable oil activated rubber powder modified asphalt is greatly reduced by about 50%,the separation softening point difference is reduced by about 27%,and the low temperature performance is enhanced by about 30%;The high temperature performance has a certain decline,but it is still much higher than the base asphalt.Thirdly,short-term and long-term aging tests were carried out on base asphalt,ordinary waste rubber powder modified asphalt and vegetable oil activated waste rubber powder modified asphalt.The results showed that the aging of modified asphalt was greatly slowed down after activation by vegetable oil.At the same content,the anti-aging performance of activated rubber powder modified asphalt is increased by about 20%.According to the results of conventional performance,rheological properties and anti-aging performance,35%of soybean oil activated rubber powder,30%of rapeseed oil activated rubber powder,and 30%of fried waste oil activated rubber powder are recommended.Finally,using scanning electron microscopy,infrared spectroscopy and thermogravimetric analysis and other microscopic testing methods,the mechanism of modification of asphalt by vegetable oil activated waste rubber powder was analyzed.The results show that the volume of the activated rubber powder increases,becomes loose,and forms many new pores,which can absorb more light components.The desulfurized and degraded activated rubber powder has improved solubility,enhanced compatibility with asphalt components,formed a stable crosslinked structure,and improved asphalt performance.Several new obvious absorption peaks are caused by vegetable oil components,that is,there is no significant chemical change during the interaction between the activated rubber powder and the base asphalt.After the rubber powder is treated with vegetable oil,the thermal stability of the modified asphalt is significantly improved.