Research On Design Parameters Of Low-Temperature Performance Of Asphalt Binders For General Highways In Liaoning Province

In recent years,the problem of low-temperature cracking of asphalt pavements has received more and more attention.The emergence of low-temperature cracking not only affects the performance of asphalt pavement,but also exacerbates the damage to the pavement,and reduce the service life of the pavement.Therefore,controlling the shrinkage crack of asphalt pavement is the key to ensure the quality of asphalt pavement.In order to improve the low temperature crack resistance of asphalt pavement,the lowtemperature cracking prediction model of asphalt pavement is formulated in the specifications for design of highway asphalt pavement(JTG D50-2017)which is issued by the Ministry of communications of China.However,whether the prediction model is suitable for the design of asphalt pavement in Liaoning Province still needs further research and verification.In this paper,the low-temperature performance index of asphalt is tested and studied,and the lowtemperature cracking prediction model is verified and modified.The low-temperature performance evaluation index and new model for low-temperature cracking prediction suitable for Liaoning Province asphalt material is put forward.The main tasks are as follows:Firstly,using clustering algorithm to classify the average temperature of January and July in Liaoning Province in the past ten years.Taking into account the annual precipitation,geographical location and other factors,the performance of asphalt pavement in Liaoning Province is divided into five areas,and based on the investigation of the geological conditions of each region in Liaoning Province,the type of subgrade soil in each region is determined.Secondly,five kinds of asphalt commonly used in Liaoning Province are tested for low temperature performance of asphalt materials,get the common index of asphalt and SHRP index.The grey correlation method is used to analyze the correlation between the evaluation indexes of low-temperature performance.The result shows that 15? penetration,penetration index PI and 15? ductility have good correlation with SHRP low-temperature index.Improve the low-temperature performance evaluation standard of asphalt materials in Liaoning Province.Third,through the viscoelastic analysis of asphalt materials,the Burgers model is used as a constitutive model for studying the viscoelasticity of asphalt materials.By analyzing the fitting degree of the curve between creep stiffness and time,it shows that it is reasonable to use Burgers model for viscoelastic fitting of asphalt materials.The creep stiffness of asphalt material at different time can be predicted by the viscoelastic parameters obtained by fitting.Provide reference value for asphalt pavement design in Liaoning Province.Finally,the sensitivity analysis of four parameters affecting the low temperature cracking model was carried out by using the orthogonal test method.Determining the design temperature of pavement is the key factor to determine the low temperature performance of Asphalt Pavement.The prediction model of low temperature cracking is verified by investigating the actual cracking of asphalt pavement.Based on this,the model is modified.A new model for predicting low temperature cracking of asphalt pavement in Liaoning Province.