| The problem of reflective cracks on asphalt pavements with semi-rigid base is serious.It is mainstream treatment method that the asphalt pavements with gravel base(AP-GB)are used to control the occurrence of reflective cracks at home and abroad.It can absorb and weaken the stress concentration in the asphalt pavement to protect the pavement structure and prolong the service life.However,due to the gravel base is loose,the AP-GB interlamination presents a complex contact form of"point-line-surface"and it will lead to pavement debonding,skidding,and be damaged.In addition,the gravel protruding from the gravel base surface will affect the interlaminar contact state.Therefore,it is necessary to systematically study the AP-GB interlaminar stability to ensure the pavement’s overall stability and serviceable life.This paper mainly proposed a new model to describe AP-GB composite structure,and the influence of the gravel embedded rate on the AP-GB interlaminar structure was considered.At the same time,three main factors were introduced into the new model to analyze their influence on the AP-GB interlaminar stability.Finally,the rationality of new model was verified by using the new specimen and its test method.The main results and conclusions were as follows:(1)The composite structure model of"viscoelastic model-cohesion zone model-random aggregate model"was proposed to simulate the AP-GB structure composed of"asphalt concrete layer-prime coat-gravel base".The complex contact form of interlamination was described by the finite element method.Moreover,in order to ensure the accuracy of the simulation results,this paper considers the influence of the AP-GB interlaminar stability when the interlamination was embedded with gravel.The definition of the interlaminar gravel embedded rate was proposed.The interlaminar shear strength under different gravel embedded rates was analyzed.The three working conditions of the gravel embedded and the failure state of the interlamination under different working conditions were introduced.(2)The composite structure model considering the interlaminar gravel embedded rate was used to study the effects of vertical load,horizontal shear speed and asphalt spreading dosage on interlaminar stability.The composite structure model with the optimal interlaminar gravel embedded rate(5%)was selected.The results show that the interlaminar shear strength increases with the vertical load and the interlaminar shear strength is positively correlated with the shear speed.In addition,as the asphalt spraying dosage increases,the interlaminar shear strength increases first and then decreases.When the asphalt spread dosage is 0.8L/m~2,the best shear strength can be obtained.(3)The"no demoulding"double-layer composite rut plate specimen and its shear test method were designed,and the composite structure model of the AP-GB were verified.The test results show that the influence of vertical load,horizontal shear speed and asphalt spraying dosage on the AP-GB is basically consistent with the simulation results,and most of the relative errors do not exceed 10%.It can be proved that the new specimen and its test method can well verify the rationality and feasibility of the composite structure model.(4)Based on the numerical simulation data and shear test data of the AP-GB.The interlaminar shear strength prediction formulas of vertical load,horizontal shear speed,asphalt spraying dosage,and gravel embedded rate were respectively proposed by data fitting.It is found that the shear strength of AP-GB can be evaluated well,and it can provide a basis for the study of the interlaminar stability.Figure[51]table[10]reference[78]... |
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