Evaluating Performance Of European Rock Asphalt Modified Asphalt Mixture

For the purpose of investigating the performance of European rock asphalt modified asphalt mixture,penetration 60 to 80 asphalt served as base asphalt and European rock asphalt served as modifier for the research.Modified asphalt binder containing up to 20%European rock asphalt was successfully prepared,and performance tests on AC-20C modified asphalt mixture with different percentages of rock asphalt were then carried out.According to the tests results,the thesis studied the effect on asphalt mixture performance which was caused by percentage of European rock asphalt.At the same time,the thesis explored the relationship between performances of European rock asphalt modified asphalt binder and mixture.All the efforts offer reference and guidance for the application of European rock asphalt modified asphalt mixture in engineering projects.Firstly,designs of AC-20C modified asphalt mixture with different contents of rock asphalt using rotation-compaction method and Marshall method were conducted.The optimum asphalt aggregate ratios were compared out of the two methods.Tests results indicate that the optimum asphalt aggregate ratios out of rotation-compaction method are a bit smaller.The optimum asphalt aggregate ratios out of Marshall method were chosen because of domestic actual condition to do further tests.Secondly,performance tests on base asphalt mixture and modified asphalt mixture were then implemented.Tests results and analyses indicate that with increasing percentage of rock asphalt,the high temperature stability,the moisture susceptibility and the water percolation resistance of the modified asphalt mixture improve.However,with increasing percentage of rock asphalt,the low temperature cracking resistance of the modified asphalt mixture increases to a peak value and then falls back slightly.In the light of the comprehensive performance,the recommended optimum use of European rock asphalt in the modified asphalt binder ranges from 10%to 20%.Thirdly,pavement structure design parameters of base asphalt mixture and modified asphalt mixture were tested.Tests results indicate that with increasing percentage of rock asphalt,compression moduli of asphalt mixture at 15? and 20 ?increase gradually.With increasing percentage of rock asphalt,indirect tensile strength at 15? increases slowly.At the same time,asphalt pavement structure was calculated.The results show that with increasing percentage of rock asphalt,maximum cumulative equivalent axle load and ultimate axle load increase.Finally,the thesis tried to find out the relationship between performances of European rock asphalt modified asphalt binder and mixture.Analyses indicate that the relationship between the high temperature performance of modified asphalt binder and the high temperature stability of modified asphalt mixture is well linear correlation.And the relationship between the creep stiffness of modified asphalt binder at-12 ? and the flexural tensile modulus of modified asphalt mixture at-10 ?is also linear.However,the relationship of the low temperature performance of European rock asphalt modified asphalt binder and the low temperature cracking resistance of modified asphalt mixture is parabolic.