Research On Preparation Technology And Properties Of Chemically Modified Asphalt By Crumb Rubber Powder

Traditional rubber asphalt has the advantages of lower overall cost and better performance,but there are some problems,such as large oil amount and poor storage stability,etc.In this paper,based on the previous research results,a chemical modifier was proposed to treat waste rubber powder,so as to improve the performance of modified asphalt.The results showed that the optimal dosage and preparation process for the preparation of crumb rubber powder modified asphalt based on chemical modification were 28%(admixture),2.5%admixture of activator,3%admixture of crosslinking agent,2%admixture of softening agent,5000r/min shear rate,180℃ shear temperature,30min shear time and 45min development time.In the high temperature performance test,the softening point and DSR test results show that the crumb rubber powder chemically modified asphalt has better high temperature performance than the ordinary rubber powder modified asphalt(rubber powder mixed with 18%)and SBS modified asphalt(SBS mixed with 4.5%).In the aspect of low temperature elongation,the low temperature elongation test at 5℃ shows that the crumb rubber powder chemically modified asphalt is still better than the ordinary rubber powder modified asphalt,but less than the SBS modified asphalt.However,in terms of low temperature crack resistance,BBR test showed that the low temperature crack resistance of ordinary rubber powder modified asphalt was the best.According to the correlation analysis results of curve fitting,the viscosity of crumb rubber powder chemically modified asphalt has a good correlation with softening point.When the storage stability was studied,the segregation experiment results showed that the storage stability of crumb rubber powder chemically modified asphalt and SBS modified asphalt was much better than that of ordinary rubber powder modified asphalt.Finally,in terms of elastic recovery,crumb rubber powder chemically modified asphalt has the best elastic recovery ability,followed by SBS modified asphalt,and ordinary rubber powder modified asphalt has the worst elastic recovery ability.Finally,this paper explores from the Angle of the micro micro modification mechanism of two kinds of modified asphalt by scanning electron microscopy(sem)experiments result,the crumb rubber powder under the action of chemical agents,it is rough surface and ravines,crumb rubber powder with no obvious interface between the matrix asphalt,almost compatible with asphalt,a combination of more reliable,were improved;According to the infrared spectrum analysis,It can be seen that the physical blending is the main modification mechanism of the general rubber powder modified asphalt,accompanied by chemical reaction,while the chemical modification mechanism of the crumb rubber powder modified asphalt has both physical blending and chemical modification.The heat absorption stability of crumb rubber powder modified asphalt is better than that of ordinary rubber powder modified asphalt.