Research On Preparation Technology And Performance Of Pretreated Crumb Rubber/SBS Compound Modified Asphalt

Rubber modified asphalt features with good performance,low cost,and good environmental protection.It has become one of the focuses of current research in the field of asphalt pavement,but it still has shortcomings in storage stability.In this paper,Pretreated crumb rubber compound modified asphalt was taken as the research object,and the rubber powder pretreated by semi-desulfurization was used as the modifier.The preparation process was researched and improved by using single factor as the variable experiment.Then compared with ordinary rubber powder composite modified asphalt,a series of research were carried out in the aspects of high and low temperature performance,storage performance,rheological performance,aging performance and micro-modification mechanism.The main conclusions are as follows.Compared with ordinary rubber powder modified asphalt,PCRCMA has better low-temperature crack resistance and lower temperature sensitivity at low temperatures.It can be seen from the DSR test that PCRCMA performs better in terms of high-temperature performance and has stronger anti-rutting ability.The temperature curve shows that PCRCMA has the highest viscosity at different temperatures.Considering the construction and workability,the viscosity should not be too large.PCRCMA is slightly inferior to the pretreated waste rubber powder modified asphalt without SBS.In terms of storage stability,it can be seen from the separation test that the performance of PCRCMA is the best,far better than ordinary rubber powder compound modified asphalt.It can be seen under the fluorescence microscope that a small amount of segregation does not start until 48h in the middle of storage.Compared with ordinary rubber powder modified asphalt,anti-aging ability of PCRCMA is more capable.Finally,this paper discusses the microscopic modification mechanism of PCRCMA from a microscopic point of view.According to the comparison of infrared spectrograms,it can be seen that the modification of rubber powder is mainly physical modification,and the rubber powder mainly plays a role of dissolving and swelling during the modification process.From the Scanning electron microscope observation,it shows that there is no obvious interface between the rubber powder particles and the asphalt in PCRCMA,and they are almost integrated,showing pits and ravines,and a small amount of SBS flocculent structure can be seen,and the overall structure is relatively dense Reticulate.Through the differential scanning calorimetry test,PCRCMA has the best temperature stability,and the best low temperature performance.The result from fluorescence microscope shows that several composite modified asphalt glues powder particles and SBS particles are staggered and dispersed,and the whole is a network structure.Compared with ordinary rubber powder modified asphalt,PCRCMA after semi-desulfurization pretreatment has a more complete reaction between rubber powder and asphalt,showing a more homogeneous appearance.