| OGFC type asphalt pavement has attracted the attention of many pavement researchers in recent years for its excellent performance of skid resistance,noise reduction and drainage.However,compared with the ordinary dense-graded asphalt pavement,the application of OGFC type asphalt pavement has been limited greatly due to large voids,less asphalt consumption,easy to loose and peeling.The use of high viscosity asphalt as a binding material for drainage asphalt pavements is a fundamental measure to overcome these defects.At present,it has a poor economy when taking the foreign high viscosity modified asphalt as a binder,while the domestic high viscosity modified asphalt is economical.But most domestic high viscosity modified asphalt have disadvantages such as poor low-temperature performance and unstable quality.In this paper,dimer acid,SEBS,and petroleum resin are selected to modify the original asphalt,and its stability has been improved by adding sulfur.Then,a high viscosity modified asphalt with good performance was prepared,its basic properties and modification mechanism were studied.The design of OGFC type asphalt pavement mixture was studied based on that,and its pavement performance was analyzed.The main research contents include:(1)60℃ dynamic viscosity is an important index according to the technical performance index requirements of high viscosity modified asphalt for drainage asphalt pavement.The penetration,softening point,ductility and 135℃Brinell viscosity were supplementary indicators.The influence of the amount of original asphalt,SEBS,dimer acid,and petroleum resin on high viscosity modified asphalt was studied by single factor experiment and multifactor experiment,and the optimal content of modified asphalt was determined.With that,the content of stabilizer is determined,and finally the optimal formula of high viscosity modified asphalt is 5%SEBS+5%dimer acid+5%petroleum resin+0.3%sulfur.The dynamic viscosity at 60℃ is 32986Pa·s,the softening point is 75.6℃,the ductility at 5℃ is 27.0cm,and the Brinell viscosity at 135℃ is 0.77 Pa·s.(2)The macroscopical experiments of adhesion test,elastic recovery test,DSR,BBR and anti-aging properties of self-made high viscosity modified asphalt were carried out.Besides,the IR,SEM,fluorescence microscopy and other microscopic tests were carried out.The test results indicated that the adhesion grade of high viscosity modified asphalt reaches grade 5 and has great elastic recovery performance.The PG grade was pg88-28.It was found that the selfmade high viscosity modified asphalt has better anti-aging properties compared with SBS modified asphalt and homemade TPS high viscosity modified asphalt.Power viscosity still>20,000 Pa.s after ageing.Fourier transform infrared spectroscopy analysis showed that the modifier and asphalt were only a simple physical blending relationship.SEM and fluorescence microscopic analysis showed that asphalt has good compatibility with a modifier.(3)The self-made high viscosity modified asphalt was selected as the binder of drainage asphalt pavement,the gradation type of drainage asphalt pavement was determined,the mixture was designed and the pavement performance was studied.The results of the study show that the mix has good roadworthiness.The test results indicated that the optimum asphalt content of the target gradation was 5.6%.The dynamic stability was more than 5000 times/mm,and the bending tensile strain at low temperature was more than 3500 με.The residual stability was greater than 85%,the freeze-thaw splitting strength ratio was 88%,the structural depth of the asphalt mixture measured by the sand paving method was greater than 1mm,and the swing value was greater than 45BPN,which has excellent pavement performance. |
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