Research On Performance And Mechanism Of Waste Rubber Power Modified Asphalts

Petroleum bitumen is widely used in various kind of transportation (road, railway,airport), construction industry, and manufacture industry etc. However, due to its ownshortcomings, such as easy to soften in hight temperature, easy to rattle in lowtemperature, not good at anti-aging, anti-fatigue.so using polymer is a very effectiveway to improve the performance of asphalt, and crumb rubber modified asphaltgradually become a focus of research at home and abroad for its superior performance,rich resources, cheap cost, simple producing process and its ability to eliminate the“black pollution” and so on.Through analyzing the routine test’s results of asphalt, this thesis discusses theinfluences on the performance of asphalt in the terms of materials, such as the size ofthe waste rubber powder particles, the content of polybutadiene, the modifiers of1,2-polybutadiene and C5petroleum resin ratio and the content of SBS, and the factorsof modification technologies, such as shearing time and shearing temperature.Adopting IR, fluorescence microscope, DSC and other modern testing methods, thisthesis analyzes infrared spectrogram of matrix asphalt, waste rubber powder modifiedasphalt and the waste rubber powder composite modified asphalt, and the level ofconsistency, the stability in temperature between waste rubber powder and asphalt,then further to discuss the mechanism of action of waste rubber powder modifiedasphalt.Through the analysis and research, we can make the following conclusions:(1) With the increase of crumb rubber, the penetration of modified asphalt drops,while its softening point rises, ductility increases, and when the content of crumbrubber reaches at15%, the optimal performance is at the best performance;(2) In a certain range, the finer crumb rubber particle is, the larger the surfacearea of the space would be, the better the asphalt modification would be. Consideringof the cost and performance of asphalt, the best waste plastic powder particle size is80mesh;(3) Chemical modifiers(1.2-polybutadiene and C5petroleum resin) and SBScan improve the performance of the asphalt, and the best content of both is6%.Comparative analysis of the impact of chemical modifiers and SBS performance of crumb rubber asphalt, we find that they have the nearly familiar effect on penetrationand softening point of the degree to crumb rubber modified asphalt, while the SBS isslightly better on ductility, through comprehensive analysis of other factors, we canconsider to use chemical modifiers to partially replace SBS;(4) The shear temperature and shear time can largely effect the performance ofcrumb rubber modified asphalt, when the shear temperature is160℃, shearing timeis1hour, the waste rubber powder can produce the best effect on modified bitumen;(5) From the infrared spectra,we know that there would take place bothchemical modification, physical dissolve and swelling effect after the penetration of wasterubber powder in crumb rubber asphalt, what’s more, the waste rubber powder changes thestructure of asphalt to some extent, thus it can significantly affect the performance ofasphalt; the images collected from fluorescence microscopy show that the waste rubberpowder have the functions both adsorption and filling; through the analysis of differentialscanning calorimetry (DSC), we can draw the conclusion that the absorption of heatand the output of heat of waste rubber modified asphalt are both less than matrix asphalt,and the temperature stability is also better than matrix asphalt.