Research On Low-temperature Performance Of Pyrolytic Waste Rubber And Plastic Modified Asphalt

The properties of rubber modified asphalt was influenced directly by the process of interaction between rubber and asphalt.In the traditional rubber asphalt preparation process,the primary reaction is the swelling of rubber power,which makes light components absorbed by rubber power to formate mutual adhesional network structure.As the reaction temperature is relatively low,the powder only produces little desulfurization cracking.This makes the role of rubber molecules,operating oil,carbon black,antioxidant and anti-aging additives in the powder in the modification of asphalt not fully exploited.In this paper,the effect of high-temperature pyrolysis on the low temperature performance of modified asphalt is studied.Firstly,nine groups of high temperature pyrolysis powder modified asphalt were prepared by high-temperature stirring process,and traditional rubber asphalt was prepared by conventional rubber asphalt processing technology.The low temperature performance of each group was evaluated by means of routine performance test,BBR test,component analysis,DMA test and DSC test.The results show that the high-temperature desulfurization and cracking of rubber powder is beneficial to further improve the low-temperature performance of the rubber modified asphalt,but it is necessary to determine the appropriate processing temperature and stirring time to avoid adverse effects on the low-temperature performance of modified asphalt caused by the excessive volatilization of light component and thermal aging.The low-temperature performance of the samples with the processing temperature of 230 ? increases with the extending of processing time,while the low temperature performance of the modified asphalt increases with the processing time at 250 ? and 270 ? trends to decrase.Among the 9 groups of high-temperature pyrolytic rubber modified asphalt,the sample prepared at 250? with stirring for 1h has the best low-temperature performance,followed by the sample prepared under 230 ? with stirring for 2 h.In the mean time,the SPSS analysis software was used to analyze the Tg data of high-temperature pyrolytic rubber modified asphalt samples obtained by DMA test and DSC test.The results show that,compared with the DSC method,the data obtained by DMA method is higher in discriminant degree and lower in variability,so the DMA method is more suitable as the Tg test method for high-temperature pyrolytic rubber modified asphalt.The results of gray correlation analysis show that the correlation between aroma content and low temperature performance is the highest,which is the biggest factor affecting the low-temperature performance of high-temperature pyrolytic rubber modified asphalt.Secondly,the rheological properties of high-temperature pyrolytic rubber/PE composite modified asphalt were evaluated and analyzed.The results show that with the increase of PE particles,the high temperature performance of composite modified asphalt is gradually increased,and the low temperature performance tends to decrease gradually.The higher the content of PE powder,the smaller the adverse effect of PE on the low temperature performance of composite modified asphalt.In order to make full use of waste resources,it is feasible to improve the high and low temperature performance of rubber modified asphalt by increasing the amount of powder,adding PE and improving the cracking degree of cracking of rubber powder.Finally,the anti-cracking property at low temperature of three asphalt mixtures were verified by the the low temperature bending test of asphalt mixture.The results show that the law of low-temperature bending strain energy density is consistent with the low-temperature performance evaluation of the corresponding asphalt samples.