Research Of Mechanical Properties And Conductive Mechanism For Conductive Asphalt Concrete Based On Micromechanics

In winter,snow and icing on road have a strong impact on road traffic security and driving comfort and bring much inconvenience on people travel.Snow melting and deicing study has become a hot research topic in the field of asphalt concrete pavement.Conductive asphalt concrete is a kind of feasible method with better effect using for snow melting and deicing.At present,most of the mechanical property and electrical conductivity of the conductive asphalt concrete were determined on the basis of indoor test.No relevant scholars proceeded in-depth theory study and mechanism study.Therefore,in this paper,we can predict elastic modulus of conductive asphalt concrete and electrical conductivity based on micromechanics.Next,we can study conductive asphalt concrete pavement with the change of the mechanical property.Further we would explore the inner conductive mechanicsm of conductive asphalt concrete.We would put forword the conductivity mechanism of conductive asphalt concrete pavement construction which has impotant guiding significance for the practical engineering application of conductive asphalt concrete.In micromechanics theory,we can better predict the scope of conductive asphalt concrete's effective elastic modulus by using Voigt-Reuss upper and lower limits.Comparing with all kinds of micromechanics methods,we can better predict the elastic properties of conductive asphalt concrete by the model of generalized self-consistent method and fiber simplification theory.Based on conductive mechanism of conductive composites,percolation theory can only predict effective conductivity when conductive particle volume fraction is greater than percolation threshold.Predicted percolation threshold often exceeds percolation threshold of test because effective medium theory(EMT)model is a kind of mean field theory.Prediced conductivity is greater than test conductivity.Based on percolation theory and effective medium theory,GEM model can better predict two-phase conductive composites conductivity considering different particle shape and distribution.But its percolation threshold still need confirm by test,GEM model existing certain limitation.We put forward simplify GEM model considering major conductivity difference between conductive particle and insulation matrix.Hashin-Shtrikman(H-S)model can only provide approximate scope of conductivity,which can not accurately predict conductivity.Based on conductive particle shape,using Eshelby tensor of flat ellipsoid inclusion and polyon inclusion,we can adopt self-consistent model to analyze conductivity of conductive composites which contain different shape conductive particle of random distribution.Because of major difference between self-consistent model percolation threshold and test percolation,we can use for reference GEM model.Based on percolation theory and self-consistent theory,we can set up modified self-consistent model.Considering flaky graphite particle belong to hexagonal system,we can choose conductive particle as hexagon inclusion more tally with the actual situation.We needn't presuppose percolation threshold,so the modified self-consisitent model has the extensive universality.Comparing all kinds of conductive mechanism,we put forward conductive mechanism based on micromechanics which can better explain conductive behavior of conductive asphalt concrete.We can proceed with finite element numerical simulation of mechanical property of conductive asphalt concrete using elastic modulus predicted value.Under standard axle load and overload conditions,we can calculate the pavement deflection,conductive bottom layer tensile stress and interface shear stress of conductive asphalt concrete pavement considering different conductive particle content.We can conclude the relationship between the mechanical properties of conductive asphalt concrete pavement and conductive particle content.Next,we can proceed with finite element numerical simulation of electrical conductivity of conductive asphalt concrete using conductivity predicted value.Considering the influence of different environment temperature,import power,wind speed and conductive particle content,we could study snow melting and deicing effect of conductive asphalt concrete and import power change.In this paper,we adopt micromechanics method to predict elastic modulus of conductive asphalt concrete.We consider conductive particle as polygon inclusion more tally with the actual situation to predict conductivity of conductive asphalt concrete.We apply the predicted value to finite element numerical simulation for mechanical property and conductivity of conductive asphalt concrete,which can reduce engineering cost and enhance precision of finite element numerical simulation.