| The development and utilization of high-performance road polymer modified asphalt is an effective way to enhance the ability of asphalt pavements to resist cracks,rutting and potholes under the combined effects of temperature,humidity and load,so as to extend the service life of asphalt pavements and achieve the purpose of low-carbon and energy-saving development of asphalt pavement construction.SBS modified asphalt has excellent performance in both high and low temperature conditions,occupying more than 90% of the asphalt pavement modified asphalt Market volume of more than 90%,but its processing compatibility,storage stability of the lack of problems is still unsolved problems.Based on this,this paper adopts C9 petroleum resin modified asphalt to enhance its performance,with the help of molecular dynamics to simulate the interaction behavior of C9 PR,SBS modified asphalt on a molecular scale.molecular dynamics study of the interaction of C9 PR and SBS modified asphalt components,the main research content is as follows:(1)To investigate the binding strength and diffusion characteristics of SBS and base asphalt components,and to reveal the molecular dynamics mechanism of the influence of SBS on the properties of base asphalt.The analysis of the molecular simulation results of SBS and base asphalt revealed that in the base asphalt,the binding energies of asphaltene with resin,aromatic and saturate were 247.522 kcal/mol,542.712 kcal/mol and 413.463kcal/mol,respectively.in the SBS modified asphalt,the binding energies of asphaltene with resin,aromatic and saturate were 262.245 kcal/mol,589.045 kcal/mol,458.424 kcal/mol,which are higher than the binding energy of asphaltene and other three components in the base asphalt,indicating that the incorporation of SBS polymer increased the strength of intermolecular interaction to some extent.The analysis of molecular diffusion coefficients revealed that the enhanced interactions between asphalt and other components inhibited the diffusion of various molecules in the asphalt system,resulting in a general decrease in the molecular diffusion coefficient of the asphalt system.The relative concentration distribution diagram shows that SBS can destroy the original colloidal system of asphalt while adsorbing the lighter components in asphalt.The study of the interaction relationship between asphalt and modifier using molecular simulation technique can be a good way to quantitatively regulate the performance study of SBS modified asphalt.(2)The basic properties of C9PR/SBS modified asphalt were investigated using macroscopic performance tests.In this paper,C9 PR was used as a modifier to select an effective preparation process of C9 PR composite SBS modified asphalt and to analyze the effect of C9 PR on the performance of SBS modified asphalt.0,3%,6%,9% and 12% of C9 PR were incorporated,and the effects of using different preparation processes on the properties of C9 PR composite SBS modified asphalt with different mass fractions were discussed.The results showed that with the addition of C9 PR,the basic properties of the modified asphalt prepared by different processing processes were improved.Based on the discovery of the mechanism of C9 PR on SBS modified asphalt performance enhancement,the molecular dynamics study of the interaction of C9 PR on SBS modified asphalt components was carried out to further analyze this.(3)The effect of C9 PR on the storage stability and compatibility of SBS modified asphalt was analyzed by molecular simulation technique to reveal the performance enhancement mechanism.The binding energy was calculated using binding energy as an evaluation index,and the results showed that with the addition of C9 PR,the interaction energy of asphaltene with resin,aromatic and saturate increased by 11.549 kcal/mol,43.003kcal/mol and 41.852 kcal/mol,respectively,indicating that the compatibility of C9 PR on SBS modified asphalt was improved.The analysis of the mean square displacement curves of the molecules of the two systems showed that the addition of C9 PR reduced the diffusion coefficient of the asphalt system,indicating that C9 PR had a physical inhibitory effect on the asphalt components,which in turn reduced the diffusion rate of the asphalt components.The structural morphology of the asphalt systems was analyzed by fluorescence microscopy and scanning electron microscopy,and the calculation of the distribution area of SBS in the base asphalt,and the skeleton length revealed that C9 PR promoted a more uniform distribution of SBS polymer in the matrix asphalt,which made the SBS modified asphalt easily form a cross-linked mesh structure.In addition,the rutting factor analysis of the three asphalt systems showed that C9 PR improved the deformation resistance of SBS modified asphalt.In this paper,the enhancement mechanism of C9 PR on SBS modified asphalt was investigated from several scales using molecular simulation,basic performance test,storage stability test,fluorescence microscopy and scanning electron microscopy.Based on the above theoretical analysis and experimental studies,the composite modified asphalt prepared by blending SBS polymer at 6% and C9 PR at 9% mass fraction has a good overall performance,C9 PR provides a light component for the dissolution of SBS polymer,and after high-speed shear,it promotes the uniform distribution of SBS polymer in the base asphalt,which has a positive effect on its storage stability.It provides theoretical support for the development of high-performance SBS modified asphalt. |
