Study On Modulus Of Asphalt Pavement Based On Different Loading Form

As an important parameter of pavement design,whether the value of modulus is accurate or not is directly related to the reasonable design of pavement structure.The difference of the value of elastic modulus will cause the change of the mechanical response of the pavement structure.At present,most of the researches on the mechanical response of pavement are confined to theoretical research,while rarely combined with field measurements.In order to study the real mechanical response of pavement,four different pavement structures were built in the test section basing on construction of a highway in Guangdong.At the same time,the fiber grating sensor is laid at the bottom of each layer of the four representative kinds of pavement structure to monitoring strain.The mixed base pavement structure is taken as the research object to study the influence of different modulus combination modes of different structural layers on the mechanical response,and evaluate the different value of elastic modulus methods by using the measured strain and deflection as the bridge.According to physical engineering,the measurement of indoor modulus and field material are strict corresponding.Tests of dynamic and static compressive resilient modulus,dynamic and static tensile-compression-bending modulus,dynamic and static direct tensile modulus were carried out.The modulus of each layer was measured by bearing plate at sensor position.The bottom strain of each structural layer and deflection is calculated by ABAQUS.This paper compares and selects the test methods for each modulus from two aspects of field measurement and simulation calculation to provide reference and basis for pavement structure design and recommend static flexural modulus as parameter of static mechanical analysis of pavement while dynamic flexural modulus as parameter of dynamic mechanical analysis of pavement Tensile strain and compressive strain of asphalt mixture and cement concrete are not the same though under the same tensile stress and compressive stress,which shows the nonlinear(bilinear)characteristics of the material.So this paper also made a preliminary study on the influence of the difference of tensile and compressive modulus of pavement material on the mechanical response of pavement structure.It is found that the difference of tensile and compressive modulus has a great influence on pavement strain response,and considering the difference can fully excavating mechanical properties of pavement material.The base of the six kinds of pavement structure are all graded broken stone in the test section,which is different from the traditional semi-rigid base asphalt pavement.Basing on a large number of field tests of bearing plate,degree of compaction,moisture content and deflection,this papper also studied the relationship of modulus tested by bearing plate and modulus back calculated by deflection of graded crushed stone and analysis the effect of various factors on the modulus of graded broken stone by grey relational analysis,reaching a conclusion that the influence factors are sorted from large to small are thickness,compaction degree,load level,water content and underlying layer modulus of graded broken stone,which provides reference and basis for the design of graded broken stone material and construction process control of pavement.