Study On The Structure And Material Optimization Of Bituminous Pavement Of Secondary Highway Under High Temperature And Rainy Conditions

Semi-rigid base asphalt pavement early rutting,cracks and water damage and other diseases;due to the high temperature and rainy climate in Jiangxi Province,early diseases are more serious.Therefore,based on the reconstruction and expansion project of Zixi Huashan boundary to Nancheng of G316 Fulan Line in Jiangxi Province,the structure and material of cement stabilized macadam base asphalt pavement are optimized under high temperature and rainy conditions in order to improve its pavement performance and provide reference for the design of asphalt pavement under the same climate conditions.Through systematic investigation,finite element numerical analysis and experimental study,the following achievements have been achieved in this paper:(1)Investigate the climatic conditions of each urban area in Jiangxi Province,divide the performance of asphalt pavement into climatic zones;at the same time,investigate the structure and diseases of asphalt pavement of second-class highway in Jiangxi Province;summarize the climatic characteristics of Jiangxi Province,the structure of asphalt pavement commonly used in second-class highway and typical early diseases.(2)Based on the relying project,using cement as anti-spalling agent,the pavement performance of the upper and lower layers with different cement content was tested in laboratory,and the results showed that the water stability of the upper and lower layers of asphalt mixture was significantly improved after adding a certain amount of cement,and the performance of AC-13 asphalt mixture was better with the increase of cement content;the cement dosage of AC-13 asphalt mixture was 1%.When the cement dosage is 2%,the water stability of AC-20 asphalt mixture is the best.When the cement content in AC-13 is 1%,the residual stability increases to 81.6% after damage,reaching 93.8% of AC-13(SBS)mixture.When the cement dosage is 0,the residual stability of AC-20 asphalt mixture is 72.1%.When the cement dosage is 2%,the residual stability of AC-20 asphalt mixture is the best,which is 80.2%.The increase was 11.2%.When the cement dosage of AC-20 asphalt mixture in the lower layer is 1%,the rutting at the middle point before and after maintenance is the smallest,that is,the water stability and high temperature stability are improved to the greatest extent at the same time.(3)Based on the orthogonal test method,the thickness and modulus of the upper layer,the lower layer and the base layer are six factors,each factor is selected at three levels,and a total of 27 typical structural combination types are formed.Then the ABAQUS finite element software is used to model the structures and analyze their mechanical response under load.It is found that the thickness of the underlying layer affects the bottom tension strain of the asphalt surface layer and the internal shear stress of the asphalt mixture.The thickness of the underlying layer has the greatest influence on the bottom tension strain of the cement stabilized macadam base layer.After research,in order to improve the anti-rutting and anti-cracking performance of pavement structure,the thickness of the underlying layer should be 8-14 cm,and the thickness of the base should be 42-46 cm.(4)Combining with the optimization of asphalt pavement material and structure,the optimization schemes under high temperature,rainy and high temperature and rainy conditions are put forward.