Research On The Optimized Preparation Process And Anti-Aging Property Of Diatomite-Crumb Rubber Compound Modified Asphalt

With the continuous development of transportation industry in China, the increasing number of car ownership, the attendant waste tire processing problems, if not handled properly will not only pollute the environment, but also cause the waste of resources.In recent years, with the study of road materials further perfect, scrap tire rubber powder as a kind of road building materials has been more and more applied to practical engineering, studies have shown that the addition of scrap tire rubber powder can significantly improves performance of the asphalt road. At the same time, diatomaceous earth as a kind of natural inorganic mineral material has the unique micro pore structure to improve the function of the pavement performance of the same. At present time,the research for rubber powder modified asphalt and diatomite modified asphalt has been relatively mature, but the study of diatomaceous earth-compound rubber powder modified asphalt is few.Preparation parameters have an important influence on the performance of rubber modified asphalt or diatomite modified asphalt, but the preparation parameters of the preparation process the in existing researches were different, the influence of the preparation technology on the asphalt performance needs to be improved.Based on above, the research content of this paper is proposed:(1) The preparation process as the preparation method of diatomite- rubber powder modified asphalt from wet process, determine the amount of rubber powder and diatomite dosage, shear time, shear rate, shear temperature and swelling time as composite modified asphalt preparation parameters, the penetration(25℃), softening point and ductility(15℃) and elastic recovery(25℃) and viscosity(135℃) as the composite modified asphalt performance evaluation index.Based on the basic principle of the response surface method, six kinds of preparation parameters in response to input values of six parameters to evaluate the performance in response to output value, to determine the diatomite- rubber powder modified asphalt preparation process optimized experimental program.(2) Based on the response surface model with good reliability, the influence of preparation parameters on the properties of the composite modified asphalt was studied by single factor analysis and multi factor analysis.The results show that the powder content has a significant influence on all the performance evaluation index, with the increase of the content of polymer, composite modified asphalt softening point, viscosity, elastic recovery and PI value increased, while the penetration and ductility decrease;Diatomite dosage had significant effects on the elastic recovery index in addition, with the increase of diatomite dosage, softening point and viscosity increased, but the penetration and ductility decrease; shearing temperature had significant effects on the penetration, softening point, viscosity and ductility index, shear temperature, shear rate and the swelling time on the properties of modified asphalt are basically the same.The optimum preparation process of diatomite rubber powder composite modified asphalt was obtained by determining the optimum value of each parameter in response to the optimal value of the output.(3) The anti aging analysis of diatomite rubber powder composite modified asphalt prepared by the best preparation technology was carried out, with the optimum dosage of diatomite modified asphalt and rubber powder modified asphalt as contrast groups, analysis of penetration, aging before and after modified asphalt softening point and elastic recovery and viscosity variation.The results show that the diatomite- rubber powder modified asphalt anti-aging performance is better than that of diatomite modified asphalt and rubber powder modified asphalt.