| Facing the global problems of climate warming and energy shortage today,highways,as an important part of my country's comprehensive development of transportation,have also been developed around the theme of green and low carbon in recent years.In terms of pavement preparation technology,warm-mix asphalt mixture has become the mainstream trend of current asphalt mixture research and development due to its outstanding advantages of energy saving,emission reduction,and environmental protection.Generally,polymer-based warm-mix modified asphalt mixtures need to undergo complicated steps such as the production and transportation of modified asphalt and the warm-mix production of on-site modified asphalt mixtures.The more complicated the steps,the more costly they will increase.The performance of polymer-based modified asphalt is reduced.Therefore,this paper will use SBS latex as a direct-input warm-mix modifier,which can modify the asphalt while realizing the production of the warm-mix asphalt mixture.The effect of SBS latex as a new type of warm-mix modifier on the performance of modified asphalt and modified asphalt mixtures was studied through laboratory experiments,so as to explore the possibility of SBS latex replacing solid SBS particles to simplify the process of warm-mix modified asphalt.The thesis first analyzes the basic indicators of SBS latex modified asphalt at different dosages,and then compares the results with SBS modified asphalt with the same solid SBS dosage,from penetration,softening point,ductility at 5°C and film oven The penetration ratio after aging and the ductility ratio at 5°C are compared in detail for the differences between the two modified asphalts.The results show that under the same SBS content,the high temperature softening point of SBS latex modified asphalt is slightly lower than that of SBS modified asphalt,and the low temperature ductility is higher than that of SBS modified asphalt.Subsequently,a48 h thermal storage test was used to analyze the storage stability of SBS latex.It was found that the higher the content of SBS latex,the storage stability of the latex modified asphalt would be adversely affected.After analyzing the basic indicators,the SHRP specification was used to classify the two asphalts with PG through rheology.The results show that the two modified asphalts have the same PG classification at the same content.The optimal content of SBS latex is selected based on comprehensive performance and economic benefits.It is 11.25wt%,and PG is classified as 76-18 at this content.Subsequently,fluorescence microscopy and Fourier infrared spectroscopy were used to compare and analyze the changes in the microstructure and chemical functional groups of the two modified asphalts,and further analyze the SBS latex from the mechanism of the modified asphalt at the microscopic level.The results show that SBS latex and SBS modified asphalt have little difference in microscopic SBS distribution and content at the same content.Finally,through the road performance test of the asphalt mixture,the performance of the SBS latex warm-mix modified asphalt mixture in terms of high temperature rutting resistance,low temperature crack resistance and water stability is explored.The results show that in terms of high-temperature rutting resistance,the dynamic stability of SBS latex warm-mix modified asphalt mixture is about 10% lower than that of hot-mix SBS modified asphalt mixture.SBS modified with HPT(anti-rutting agent)is added.The dynamic stability of the flexible asphalt mixture can reach the same level as that of the conventional hot-mix modified asphalt mixture;in terms of low-temperature crack resistance and water stability,the SBS latex warm-mix asphalt mixture is significantly better than the hot-mix SBS modified asphalt Mixture. |
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