Evaluating Performance Of Bioasphalt Modified Asphalt Mixture

Bioasphalt has caught widespread attention from domestic and international scholars due to its remarkable economic,environmental and social benefits.For the purpose of investigating the performance of bioasphalt modified asphalt mixture,penetration 40 to 60 asphalt served as base asphalt and Castor Oil-based bioasphalt served as modifier for the research.Modified asphalt binder containing 0%to 20%bioasphalt was prepared,and performance tests on AC-20C modified asphalt mixture with different percentages of bioasphalt were then carried out.According to the tests results,the thesis studied the effect on asphalt mixture performance which was caused by percentage of bioasphalt.Then,the upper limit of the percentage of bioasphalt was determined.At the same time,the thesis explored the relationship between performances of bioasphalt modified asphalt binder and mixture.All the efforts offer reference for the application of bioasphalt modified asphalt mixture in engineering projects.Designs of AC-20C modified asphalt mixture with different percentages bioasphalt using rotation-compaction method and Marshall method were conducted.The optimum asphalt contents were compared out of the two methods.Through analysis,the optimum asphalt contents out of Marshall method were chosen for further testing.Performance tests on asphalt mixture were then implemented.Tests results and analyses indicate that with increasing percentage of bioasphalt,the high temperature stability and the moisture damage resistance of the modified asphalt mixture decrease,and the water percolation resistance increased after an initial decrease.They all meet the requirements of JTG F40-2004 within a certain range of percentage.The moisture damage resistance improves significantly by adding hydrated lime.With increasing percentage of bioasphalt,the low temperature cracking resistance of the modified asphalt mixture increases.In the light of the comprehensive performance,the recommended upper limit of the percentage of bioasphalt in the modified asphalt binder was 12%.Pavement structure design parameters of asphalt mixture were tested.Tests results indicate that with increasing percentage of bioasphalt,compressive resilient modulus of asphalt mixture at 15? and 20? decrease.With increasing percentage of bioasphalt,the indirect tensile strength at 15? decreases to a minimum value and then increases slightly,base asphalt mixture has the maximum indirect tensile strength at 15?.Finally,the thesis tried to find out the relationship between performances of bioasphalt 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 basically linear dependent.However,the relationship between viscosity at 60? of bioasphalt modified asphalt binder and the high temperature stability of modified asphalt mixture is non-linear and needs further investigation.The relationship of the low temperature performance of bioasphalt modified asphalt binder and the low temperature cracking resistance of modified asphalt mixture is also linear.