Impact On Rubber Modifier Of The Properties Of Asphalt And Mixtures

At home and abroad highway construction, the most widely used pavementmaterial is SBS modified asphalt pavement. SBS modifier is one of petroleumproducts, because the heavy using of SBS modified asphalt, it was led to manyproblems, such as SBS in a high price and non-renewable. Rubber modified asphalt,because of its good performance, has used in the domestic and abroad Highway.Storage stability of rubber modified asphalt and high energy consumption during thetransportation and using procedure are the reason to restrict the development ofrubber asphalt mixture. In this paper, a new rubber modifier named RM was used asan additive to prepared RM modified asphalt and its mixture and evaluated theirperformance. The properties between SBS modified asphalt and RM modified asphaltwas compared, while their mixtures performance and economics evaluation were alsobeen compared. The main research works are as follows:Firstly, the properties of the RM modified asphalt, SBS modified asphalt andbase asphalt, including physical properties and rheological behaviors, werecomparative analyzed. By three major indicators test, It is indicates that RM canobviously improved asphalt of basic performance. DSR test results indicate that theaddition of RM has complex influence on rheological properties of the asphalt. At thehigh region, by adding the RM to asphalt, complex modulus increased while phaseangle reduced. And at low temperature, the obtained results were opposite. Obtainedresults indicated that properties of asphalt, including high temperature ruttingresistance performance and low-middle temperature fatigue performance of asphaltwere improved by addition of RM. It was known that, through high temperature creeptest and cryogenic stress relaxation test, the addition of RM can upgrade creeprecovery volume and cut down relaxation time of asphalt.Secondly, the pavement performance among the asphalt contented RM mixture,SBS modified asphalt mixture and base asphalt mixture, including water stability,high temperature performance and low temperature performance, were investigated,freezing and thawing split test results indicated the asphalt content RM has slightly worse water stability performance than SBS modified asphalt mixture, the addition ofRM was improved dynamic stability of the mixtures, relative deformation would bereduced. The low temperature cracking resistance of RM modified asphalt mixture isbetter than the base asphalt mixture while the SBS modified asphalt mixture isslightly better than RM modified asphalt mixture.Thirdly, the Simple Performance Test commented by SHRP is conducted tostudy the dynamic modulus and fatigue properties of three kinds of asphalt mixtures.The results show that the frequency dependence and temperature dependence wereremarkable for dynamic modulus and phase angle of mixtures. The dynamic modulusof mixtures with RM was increased while the phase angle was decreased. And theresults of dynamic modulus tests showed that the viscoelastic characteristic of RMmodified asphalt mixture is better than SBS modified asphalt mixture. The dynamicmodulus master curves of three kinds of mixtures were obtained by adopting theTime-Temperature equivalence principle. The results showed that the temperaturesensitivity of mixtures was reduced by adding RM. The relationship between dynamicmodulus and phase angle can be characterized by a semilog model. The fatigueproperties of mixtures were improved by adding RM, especially at high stain level.The fatigue performance of RM modified asphalt mixture is slightly lower than SBSmodified asphalt mixture at low stain level. However, at the high stain level, thefatigue properties of two mixtures are nearly same. With the cost analysis of mixtures,the addition volume of RM on this article could make the same function factor butlower cost compared SBS modified asphalt mixtures.