Study On Temperture Field And Rutting Disease For The Highway Asphalt Pavements In Fujian Province

The main weather of Fujian Province is hot and rainy in summer. With theeconomic development, the highway transportation has grown rapidly in recent years;however the heavy traffic is very common. It is not helpful to keep the service ofpavements and extend the service life that serious tracking distress happens to theasphalt pavements in highway which is used only two or three years. With thisbackground, this paper is mainly about the study, which is based on the twocharacteristics, high temperature and heavy traffic, to the mechanisms, characteristicsand control techniques to the tracking distress in the highway asphalt pavementsaround Fujian Province. The methods which conclude on-site survey, disease analysis,temperature field monitoring to the highway asphalt pavements in Fujian Province,laboratory testing and theoretical rutting simulation analysis, are used to carry on thestudy. The main details are followed.First of all, the status about tracking distress of highway asphalt pavement isanalyzed through the field investigations to the highways in the whole province. Thencombined with the specific section of pavement structure, materials, regionalenvironmental parameters, characteristics of the disease, causes and influencingfactors to it are analyzed. The study finds that the main kind of tracking distress isunstable tracking distress, and that high temperature, heavy traffic, pavement structuretogether with materials and are the main factors leading to rutting.To understand the characteristics of temperature field to the asphalt pavement,four temperature observation stations had been set up in four different sections ofhighway asphalt pavements in Fujian Province. A large amount of basic data isreceived through the monitoring lasting nearly a year, which gathers the temperaturefields in different depths to the two kinds of asphalt pavement structure around threedifferent seasons. By analyzing it, the research obtains temperature fieldcharacteristics to the structure of asphalt pavement in Fujian; and estimating statisticalmodels and finite element models are taken to show how the temperature fields are inhigh temperature in different parts of Fujian. It finds that solar radiation andtemperature are the major reasons to the high temperature of the asphalt pavements inFujian, and regional climate and the structure of the road make the temperature fieldsof the asphalt pavements different.In order to understand the mechanism to the rutting, based on the temperaturefields in Fujian Province, the typical pavement structure and material parametersobtained by experiments, with the help of the nonlinear finite element analysisprogram, ABAQUS, computational models to asphalt pavement rutting under continuousvariable temperature conditions are founded. Also the paper has studied thehigh-temperature stability of the asphalt mixture gradations and the anti-ruttingperformances in different grade-mates, together with rutting development laws at different climates in Fujian and the influence to the rut, which high temperature,heavy load, pavement structural composition and the thickness of asphalt surfacecourse result in. The study finds that the time that the rutting mainly happens, which issignificantly affected by temperature but laggard, mainly happens between10:00to18:00in high-temperature season; that the largest value of the creep strain occurs at7cm under the road surface while major region of the rutting is between4cm to10cmunder the road surface; that semi-rigid base is a bit better than flip-style; that thethicker the thickness of asphalt surface course is, the greater the amount ofaccumulated deformation is.Derived from the above, the paper proposes the method to control the rutting forasphalt pavement. Firstly, prediction model to rutting for asphalt pavement in Fujianwhen the weather is hot is founded, which is based on label-tire pressure and loadtime, together with the temperature when the rutting happens, so that it is possible tocalculate and to evaluate the development of the rutting. So finely conversionformulas based on equivalent axle load of heavy traffic and the proposed methods tocalculate service life of the asphalt pavement are proposed. From the above, asphaltpavement design methods mainly for rutting are proposed. Then combined withbitumen consistency and mixture dynamic stability, index and standards used to selectthe asphalt are raised. And rutting control technology is derived from the unity ofstructure and materials, road construction control and maintenance managementtechnology.