| With the increasing of road axle load,the road surface diseases are occurring more frequently at this stage,which leads to the maintenance cost rising year by year.At the same time,the annual production of waste plastics in the world is huge,but it has not been well recycled.In order to respond to the call of national energy conservation and emission reduction,and further reduce the cost of pavement maintenance,this paper uses waste plastic as an asphalt modifier,in order to achieve the purpose of sustainable recycling waste plastic.Based on the optimum preparation process of waste plastic asphalt research,the performance and modification mechanism of waste plastic asphalt were further studied.The main research contents are as follows:First of all,through the analysis of the characteristics of different plastics,three commonly used waste plastics were selected.According to the preparation process of plastic asphalt,the mixing proportion,mixing time,mixing temperature and other indicators of waste plastics were analyzed.The orthogonal test was then used to analyze the changes of basic properties from the perspective of penetration,softening point,ductility and viscosity.Consequently,the optimum process parameters of waste plastic modified asphalt were as follows:PE optimum content is 5%,shear time is 30min,shear temperature is 170℃,shear rate is 3000r/min;PP optimum content is 9%,shear time is 30min,shear temperature is 170℃,shear rate is 3000r/min;EVA optimum content is 5%,shear time is 60min,shear temperature is 180℃,shear rate is 3000r/min.Secondly,in order to comprehensively analyze the physical and mechanical properties of the above three kinds of plastic asphalt,5 kinds of polymer modifiers were selected for comparison,and their conventional physical properties of were compared.The test results show that the plastic can help to improve the high temperature performance of asphalt,with negligible effects on the low temperature performance.In addition,the penetration test results show that the temperature sensitivity of waste plastic asphalt is reduced,which helps to improve the anti-rutting performance of asphalt pavement.The rotational viscosity test results show that the viscosity increases due to the addition of plastic,but the maximum value does not exceed the specification value of road asphalt,which indicates that waste plastic asphalt can meet the workability requirements of construction at high temperature.Furthermore,by means of TGA,DSC and FTIR,the changes of functional groups and internal stability of plastic asphalt were analyzed,and the relationship between plastic and asphalt was clarified.FTIR test results show that the main characteristics of waste plastic modified asphalt are that the C-H stretching vibration absorption peaks of cycloalkanes and alkanes are in the range of 2850cm-1～2990cm-1,the variable angle vibration absorption peaks of CH3 and CH2 are in the range of 1450cm-1 and 1370cm-1,and the absorption peaks are in the range of 700～900cm-1,The results show that the main reaction process of plastic asphalt is physical change.TG-DSC test results show that the waste plastic modified asphalt shows good thermal stability,and its mass loss is reduced by about 33.33%due to its absorption and reduction of light components in asphalt,which indicates that the mass loss of waste plastic modified asphalt is less.Also,the area of endothermic peak and exothermic peak of DSC curve of waste plastic modified asphalt increased,indicating that its temperature sensitivity decreased.Finally,based on the results derived here in this paper,the optimal performance indicators of waste plastic modified asphalts,as well as the most appropriate of them for use in high temperature regions were recommended,and thus,their appropriate direction was clarified. |
PDF Full Text Request