| Asphalt pavement because of its numerous advantages,got the wide application of the highway,it has enough mechanical properties to forces under the vehicle load,surface smoothness is good,high driving driving comfort,and tire has good adhesion,shock absorption,and quiet is good,easy to clean with clean,easy to maintenance etc.China’s vast land,natural conditions vary greatly,often in different areas with the same quality and the same pavement structure under roughly the same load,the speed and severity of damage are not the same.Obviously,the role of various external environmental factors is the main reason leading to this situation,and among many external environmental factors,the combination of temperature and humidity has a particularly obvious impact on the performance of asphalt pavement.Therefore,it is of great significance to study the performance evolution law of asphalt pavement under the combination of temperature and humidity on the basis of laboratory tests,for analyzing the performance variation law,service condition evaluation and maintenance of asphalt pavement in different environmental areas.The thesis mainly carries out the following research work:First of all,the relevant data of Chongqing from China Meteorological Data Network were collected.Based on the obtained meteorological data,the characteristics of temperature and humidity combination environment in Chongqing were statistically analyzed,and the temperature and humidity domains in Chongqing were obtained.According to the function relationship between temperature and absolute humidity,as well as the conversion relationship between relative humidity and absolute humidity,the temperature and relative humidity which are in line with the characteristics of temperature and humidity environment in Chongqing are selected.And,in order to achieve the purpose of indoor simulation of temperature and humidity combination environment,a temperature and humidity combination environment test chamber is designed and assembled by ourselves,which can control the temperature and humidity conditions independently.Secondly,the modified asphalt AC-13 asphalt mixture which is widely used in engineering is taken as the research object.By putting the asphalt mixture specimen into the self-made temperature-humidity combination environment test chamber,and acting for a certain time under the preset temperature-humidity combination condition,the evolution law of its high temperature stability,water stability,low temperature crack resistance and fatigue performance with the change of temperature and humidity environment condition was studied.Finally,a four-point bending fatigue test was carried out on the specimens of the mixture subjected to different temperature-wet combined environments.Based on the test results,an appropriate fatigue life prediction model was selected to modify the prediction model from the perspectives of the number of days in unfavorable seasons,the interval time of load action and the speed of crack propagation.The fatigue life prediction model of asphalt pavement under the combination of temperature and humidity is obtained.The experimental study and result analysis show that the dynamic stability value obtained from rutting test decreases to a certain extent with the increase of ambient temperature and humidity,and the influence of ambient temperature is stronger than that of ambient humidity.In terms of water stability,the residual strength ratio of freeze-thaw splitting obtained from the test shows that the water stability of the specimen decreases with the increase of ambient temperature,and humidity also has a negative effect on it.However,the attenuation effect gradually decreases with the increase of humidity.As for the influence of the combination of temperature and humidity on the low temperature crack resistance,the bending tensile strength and the maximum bending tensile strain obtained from the test show that the low temperature crack resistance gradually decreases with the increase of ambient temperature and humidity,but the influence on the low temperature crack resistance gradually decreases with the increase of ambient humidity.According to the fatigue test analysis,the fatigue life of asphalt mixture specimens decreases with the increase of the temperature of the temperature-humidity combination environment,but with the increase of the temperature,the sensitivity of the fatigue life of asphalt mixture specimens to the change of strain level decreases,and the trend of the fatigue life decreases with the increase of strain level is less obvious. |
