Research On Pavement Performance And Construction Technology Of Asphalt-rubber Mixture

The ‘11th Five-Year’ Key Research Project launched by Ministry of Science and Technology has madesignificant instructions on China’s building of resource-conserving, friendly society as well as on our basic statepolicy of thoroughly applying resource conserving and environment protection. As the modifier of matrixasphalt, rubber powder could not only improve the using function of matrix asphalt but also enhance the roadservice quality and extend its service life. In the meantime, rubber powder could make full use of a largenumber of junked tires pollution-freely and recycling, which exerts great importance on our country’ssustainable development and on relieving the environmental stress brought by junked tires.Firstly, this paper is going to focus on analysis of parameter and mesh number of rubber powder,temperature and time of stirring as well as the influence of rubber asphalt performance by means of laboratorytest; the optimal modified parameter combination of the preparation of rubber asphalt would be determined byrange analysis; secondly, rubber asphalt mixture’s mix proportion of continuous grading, discontinuous gradingand gap grading would be designed respectively via Marshall testing method and the different grading mixturewould be tested based on high temperature rutting test, low temperature bending test, freeze-thaw splitting testand fatigue test; finally, the construction quality of rubber asphalt mixture of gap gradation would be testedthrough the paving of experimental roads, which concludes the construction technology of rubber asphaltmixture.The experimental result shows that the performance of asphalt rubbers is different according to differentparameter combinations, among which the parameter of rubber powder is the most significant factor, followedby the mesh number of rubber powder. The recommended optimum parameter combination is that theparameter of rubber powder is22%, the mesh number of rubber powder is80, the blending time is60mins,and the blending temperature is200℃; The optimum volume of different asphalt rubbers vary according todifferent graduation, among which, the volume of discontinuous grading and gap grading is relatively larger,and they respectively increase by32.1%and39.3%, compared to continuous grading. Furthermore, with theoptimum volume of asphalt, the asphalt rubber mixture of different grading shows preferable volume index.Compared to matrix asphalt, rubber asphalt improves a lot in its high temperature stability, low temperatureanti-cracking performance, water stability and fatigue performance, which shows that added rubber power helpsto promote all performance. As for different grading rubber asphalt mixture, the discontinuous grading’s high temperature stabilityand low temperature anti-cracking performance are prior to continuous grading’s and gapgrading’s, however, the discontinuous grading’s water stability is slightly lower than gap grading. Based on theperformance analysis of different grading’s rubber asphalt, the fact that rubber asphalt is more suitable todiscontinuous grading SMA is confirmed; in addition, raw material and the construction process are the mostimportant factors contributing to the construction quality of rubber asphalt, which should be strictly limited inthe corresponding technical index and requirement. One important thing is to control the temperature of thestages of mixing, transportation, paving and rolling, which guarantees the quality of rubber asphalt mixture’smeeting the requirement of the specifications.