基于疲劳损伤的沥青路面设计温度及预估模型研究

针对沥青路面结构必须控制的疲劳破坏形式,以沥青层层底拉应变作为控制沥青路面疲劳开裂的指标。通过实测沥青面层层底最大拉应变与路面结构不同深度处路面温度的相关性分析,确定了沥青路面疲劳损伤的设计温度,提出了以沥青层中间温度作为沥青路面疲劳开裂分析的设计温度和试验条件。通过实测永久性沥青路面试验路每小时的路面温度和气象数据,分析了沥青层中间温度的分布规律,对沥青层中间温度与气温、路面深度之间的相关关系进行了计算分析,建立了沥青层中间温度的预估模型。结果表明,沥青路面应变响应与温度密切相关,随着路面温度的升高,沥青层底拉应变增大;沥青层中间深度处温度与沥青层底拉应变相关性最高,采用沥青层中间深度处温度能较好地评价路面结构的抗疲劳性能。

Design Temperature and Its Prediction Model for Asphalt Pavement Based on Fatigue Failure

With regard to the fatigue failure which must be controlled in asphalt pavement,the tensile strain at the bottom of the asphalt layer Was taken as the controlling index for fatigue cracking of asphalt pavement.By analyzing the correlation of the temperature at different depths of asphalt pavement with the measured strain response at the bottom of asphalt layer,the design temperature for the fatigue failure of asphalt pavements were determined,taking the temperature at the middle of the asphalt layer as the design temperature and the test condition for the analysis of the fatigue failure of asphalt pavement.Hourly pavement temperatures and meteorological data were measured in the selected perpetual pavement,the distribution of the temperature at the middle of the asphalt layer were studied.Through calculating and analyzing the correlation of the temperature at the middle of asphalt layer with air temperature and different depths below the pavement surface,the prediction model of midge-depth temperature of asphalt layer was put forward.The results show that(1)the value of strain response of asphalt pavement is closely related to the pavement temperature,the tensile strain at the bottom of the asphalt layer increases with the pavementtemperature increase;(2)the correlation between the temperature at the middle of asphalt layer and the tensile strain at the bottom of asphalt layer is the highest,which can better assess the ability of anti-fatigue performance by using the temperature at the middle of asphalt layer.