Study On Cracking Resistance Of Asphalt Pavement In Cold Regions Of Hebei Province Based On Regional Characteristics

In the northern cold regions,the low-temperature cracking of the pavement is a kind of common pavement distress.The cracks will continue to develop under the combined effect of temperature changes,rain and traffic load.The strength and stability of the pavement are greatly threatened after the water penetrating into the internal of pavement structure through the cracking,leading to huge economic losses.Therefore,higher requirements are placed on the low-temperature cracking resistance and service life of asphalt pavement in cold regions in the north,and also on the construction cost and investment benefits.First,based on the cracking investigation of highway in the northern region of Hebei Province,combined with the climatic and environmental changes of the locations of the highway,a model of climatic characteristics was established.According to this model,the January climate data in this area can be used as a reference to study the low-temperature crack resistance of the pavement.Secondly,based on the characteristic climate of Huailai,the temperature of low-temperature performance test was determined.The low-temperature performance of asphalt was evaluated by 5 ~oC ductility,brittle point test,BBR test,and the low-temperature performance of asphalt mixture was tested by low-temperature beam bending test and low-temperature split test for optimal asphalt materials.The dispersion of the test data was analyzed based on the low-temperature beam bending test and the low-temperature split test,and result shows that the split strength is more suitable for evaluating the low temperature performance of the asphalt mixture.Then,the ABAQUS finite element software was used to establish temperature field model of the asphalt pavement structure based on the the asphalt pavement with flexible base used in the test road.Combined with the climate data of Huailai,the asphalt pavement temperature distribution was analyzed,and the time-space change law of the temperature of the flexible base asphalt pavement structure used in the test road was summarized to provide a basic guarantee for thermal stress calculation and theoretical analysisFinally,by calculating the thermal stress of asphalt pavement in different environments,the applicability of different structures in cold regions was compared.Under certain environmental conditions,the low-temperature cracking resistance of the flexible base asphalt pavement is better than that of the semi-rigid base asphalt pavement,but with the conditions gradually deteriorating,the low-temperature performance of the upper layer material becomes the key factor for the pavement structure to resist low-temperature cracking.Therefore,when designing the asphalt pavement,it is necessary to consider the integrated design of the pavement structure and materials according to the local climate environment characteristics.