Research On Dielectric Constant Of Asphalt Mixture

This paper takes the asphalt pavement project of Wuhan west fourth loop line as the engineering support,with the non-destructive testing theory,on the basis of selecting the existing dielectric model of asphalt mixture,this paper derived the relationship between dielectric constant and density,asphalt content of asphalt mixture and clarified the influence relations of testing frequency and temperature condition,then verified the practical value of relevant theories by experimental analyzing of each core sample of asphalt pavement of Wuhan west fourth loop line.The main conclusions and findings are as follows:(1)This paper made an optimized selection by comparing the existing dielectric models of asphalt mixture,and deriving the dielectric model of asphalt mixture with good applicability,then the dielectric model which can be suitable for asphalt mixture is determined.(2)This paper derived the relationship between dielectric constant and two engineering indexes include density and asphalt content of asphalt mixture and verified the practicability of this relationship by indoor test.The result shows that the deviation between the calculated value and the actual result is small and proves it's practical to expand the content of GPR by building the relationship between dielectric constant and density,asphalt content of asphalt mixture.(3)Combining the asphalt pavement project of Wuhan west fourth loop line,this paper got some core samples of each layer of asphalt pavement by drilling core to verified the reliability and practicability from the point of view of engineering practice.The result shows it's feasible to use GPR to detect the density of asphalt pavement,but it's need more research on the detection of asphalt content of asphalt pavement because of the actual factor influence.(4)As for the influence of testing frequency and temperature condition on the accuracy of GPR,this paper established the dielectric model of asphalt mixture based on testing frequency and temperature condition by theoretical derivation,and verified the reliability and practicability of the model by continuous temperature variation test based on control variable method.The result shows that the testing frequency and temperature do have some influence on asphalt mixture,and conforms to the theoretical model proposed in this paper.In summary,the research results of dielectric model of asphalt mixture build the relationship between dielectric constant and some engineering indexes from theoretic,effectively extend the content of GPR non-destructive test,explicit the influencing law of external factors,and provide a reference for the practical application of the project.