Study On Asphalt Pavement Permanent Deformation Prediction Based On Superposition Principle In Full Temperature Range

The permanent deformation of asphalt pavement has been one of the key problems in the current research.For the construction of semi-rigid base asphalt pavement in our country,the permanent deformation of asphalt pavement is mainly focused on the structure of the surface layer.The permanent deformation of asphalt layer has become one of the main diseases of asphalt pavement.The current analysis of asphalt pavement permanent deformation mainly focus on the high temperature stage,while less on the low temperature phase,and often ignore the temperature differences between different layers in the pavement structure and the frequency characteristics of distribution throughout the year.Considering environment temperature and traffic load,in order to more accurately,scientifically and reasonably estimate the asphalt pavement permanent deformation,therefor propose a systematic prediction method of asphalt layer permane-nt deformation,the paper initially established a superposition rule for permanent deformation of asphalt layer from the whole temperature range.the rule is built on the base of rheology theory and superposition principle by the engineering research,indoor test,theory analysis and numerical calculation and such kind of comprehensive research methods.The The main research results and conclusions are summarized as follows:(1)by statistical analysis and researching the Asphalt Pavement Rutting on 6 highways in Chongqing City,Jiangxi province and Yunnan province,summarizes the characteristics and causes of rutting of asphalt pavement in expressway,and divided the rutting depth into four sections in the intervals of 5mm to spectrally analyze the rut depth and more accurate evaluate the asphalt pavement rutting damage.At the same time,this paper puts forward the probabilistic algorithm of calculating the average depth of the whole length of the pavement as the field measured value,which provides the data support for the prediction of asphalt pavement permanent deformation and the correction of the model.(2)make the asphalt pavement in Chongqing City,middle area of Jiangxi province and Yunnan Province be the research object,the temperature of 1cm below road surface be the representative temperature and make 5? be internal temperature to divide temperature section,get control index of temperature distribution in full temperature range by the field measurement and model calculation,that is,the whole year temperatu-re distribution frequency of the asphalt pavement and the temperature distribution curve along the depth of asphalt layer.At the same time,build the prediction model of asphalt pavement structure temperature,which consists of asphalt pavement structure temperat-ure T,road surface temperature To and the depth of pavement structure layer h,the full coverage of the effect of temperature on the permanent deformation of asphalt pavement is realized.(3)propose the highway typical type axle,axle combination form and transverse distribution characteristic by collecting highway traffic load characteristics and surveying the field axle load of many highways in Jiangxi province and Yunnan province.Calculatedly get the distribution map of single axle double wheel,double axle double wheel and triple axle double wheel of many highways in Jiangxi Province and Yunnan province by collecting the models ratio,distribution frequency of representative vehicle axle load.after matrixing axles numbers,finally get the axle load distribution map of Uniaxial two-wheel group of Expressway Asphalt Pavement and then provide the data support of traffic axle load distribution for the following study.(4)According to triaxial repeated load permanent deformation test,the relationship curves between the load action times and the permanent strain of asphalt mixtureAC-13,AC-16,AC-20,AC-25,SMA-13and ATB-30 were obtained in different temperature and different deviatoric stress and systematically study permanent deformation rules in different stage of low,middle and high temperature.Based on rheology theory,the viscoelastic model of asphalt mixture under repeated loading is derived based on modified burgers model,and the parameters were fitted,the effect is good.the paper carried out the general research of the asphalt mixture viscoelastic elasticity model,that is to build the relationship equation of temperature,deviatoric stress and mechanical model parameters,and solve the permanent strain of asphalt mixture under arbitrary temperature and arbitrary stress conditions.At the same time,by carrying out the dynamic modulus test of asphalt mixture,systematically analyze the effects of temperature and loading frequency on dynamic modulus,establish the dynamic modulus master curves of six kinds of typical asphalt mixtures.(5)the prediction method of permanent deformation of asphalt pavement under the condition of full temperature field is proposed.Through modeling calculation analysis deviatoric stress distribution rule of the typical pavement structure is obtained,and make out the deviatoric stress variation coefficient with the change of the driving speed,base modulus,base thickness and surface layer thickness;establish the prediction model of the deviatoric stress distribution of asphalt layer in different temperature range.By introducing the idea of Partition Graded Layered,that is,Temperature partition,axle load classification,pavement stratification,based on permanent strain calculation method of the superposition of cumulative load times,propose the correction model of permanent deformation prediction of asphalt pavement based on superposition principle under the condition of full temperature field,and the theory correction coefficient is 1.93,the temperature correction coefficient isl.06(temperature distribution below 20? can be ignored),Which provides a new method for the comprehensive and accurate estimation of permanent deformation of asphalt pavement.(6)The simplified model of asphalt pavement permanent deformation prediction based on the temperature distribution in the full temperature range is proposed,that is,the relation equation between the average permanent deformation of asphalt pavement in the temperature range and the number of times of load action,and the relation equation among the permanent deformation and the average permanent deformation in the temperature range and temperature distribution frequency,which provides a new way for rapid prediction of asphalt pavement permanent deformation under full temperature field.