Study On The Resistance Of Asphalt Concrete Pavement To Water Damage Under Different Drainage Condition

Asphalt concrete pavement has many advantages such as high strength,high temperature resistance,simple construction and reliability.However,the asphalt concrete also has defects,and one of the most serious problems is the early damage within two years in service,which greatly increases the cost of road maintenance.Especially in the highway,frequent maintenance is not only costly,but also causes road congestion,consequently,which brings great inconvenience to people's life.Therefore,it is of practical significance to study the mechanism of early damage of asphalt concrete pavement,and to find the prevention or repair measures.Factors causing early damage of asphalt concrete pavement are numerous.However,this paper only focuses on the problem of water damage.In 1996,the United States asphalt research institute clearly pointed out that the most important factor leading to the early damage of the asphalt concrete pavement is water.At home and abroad,most of the researches on asphalt concrete pavement are conducted by tests which is not only complicated,but also requires a lot of equipment,and there is no systematic experimental process to ensure the reliability of the results.Compared with the experimental study of asphalt concrete pavement,the numerical simulation method is a more efficient way to study the water damage of asphalt concrete pavement.In this paper,using the theories of fracture seepage and fluid structure coupling,the load response of the asphalt concrete pavement with cracks under different drainage conditions is studied.Taking a real world road case as an example,using Comsol finite element platform,the three-dimensional fluid-solid coupling model of asphalt concrete pavement is established with the consideration of three kinds of crack(vertical cracks,horizontal cracks and cross cracks)and three kinds of prevention-control drainage measures of asphalt concrete pavement.The calculation results show that: 1)using the theory of fracture seepage,peak pore water pressure and its change rule could be calculated correctly under different cracks and drainage conditions,which verifies the validity of the method;2)under lower drainage condition,pore water pressure generated in the pavement is the smallest,which means that pavement with the lower drainage condition owns the strongest ability of resisting the water damage;3)Pavement with the transverse or cross cracks has the poorest ability to resist water damage,so it is suggested that maintenance should be timely performed in that situation.