Research On Preventive Maintenance Technology Of Asphalt Pavement Based On Penetrating Regeneration

Highway is an important part of transportation system in China,which is of great significance to the development of national economy and the promotion of modernization.Asphalt pavement has the advantages of driving safety and comfort,low noise,good anti-wear property and convenient maintenance,and is widely used in highway construction.With the rapid growth of the national road mileage and the extension of the road service period,the development of asphalt pavement in China has gradually changed from the peak period of construction to a period of equal emphasis on construction and maintenance,and the maintenance of asphalt pavement is increasingly important.There are some problems in traditional pavement reconstruction,such as resource waste,high cost and environmental pollution.Preventive maintenance technology based on penetrating regeneration has a lot of advantages such as saving resources and effectively extending the service life of asphalt pavement with limited maintenance funds,so as to achieve the purpose of repairing the early distresses of pavement.Based on this,this thesis studies the mechanism of action,application methods and application effect of preventive maintenance technology based on penetrating regeneration.Firstly,the thesis summarizes the types and causes of early distresses of asphalt pavement and analyzes the maintenance timing and common maintenance measures of preventive maintenance technology of asphalt pavement.And the application conditions of preventive maintenance technology based on penetrating regeneration are put forward.Combining mechanisms of asphalt aging and regeneration,the technical performance requirements of rejuvenation agents,and the permeability and aging resistance of three rejuvenation agents(Type I,Type II,Type III)are detected and evaluated through laboratory tests.Experimental results show that the permeation rate decreases with the extension of penetration time,and permeability and aging resistance of type I regenerant are the best.Secondly,the laboratory tests of the rejuvenation agents are carried out in this thesis.The regenerated modified asphalt is obtained by adding three rejuvenation agents respectively to the aging modified asphalt according to different mass ratios(2%,4%,6%,8% and 10%).The basic properties of regenerated modified asphalt(penetration,softening point,ductility)are tested,and the rheological properties are tested by Dynamic Shear Rheometer(DSR)and Bending Beam Rheometer(BBR)instruments.The regeneration effect of rejuvenation agents on aging modified asphalt is evaluated,and the optimum dosage of three rejuvenation agents is determined.The experimental results indicate that rejuvenation agents have obvious regeneration effect on the aged modified asphalt.The penetration and ductility of the regenerated modified asphalt increase and the softening point decreases.And the optimal dosage of the rejuvenation agents should be 6~8%.At the same time,the fatigue resistance and low temperature crack resistance are improved,but the high-temperature deformation resistance is decreased.The basic properties of the modified asphalt in different conditions are tested by repeated aging and regeneration tests,and it is found that the basic properties of the secondary regenerated modified asphalt are weaker than that of the primary regenerated modified asphalt,and the feasibility of multiple regeneration is verified.And it is suggested that the amount of rejuvenation agents for secondary regeneration should be increased by 4% on the basis of the amount of primary regeneration.At last,in order to verify the practical application effect of the rejuvenation agents,the construction technology and construction process of the preventive maintenance technology based on penetration regeneration are introduced by combining experimental roads of Dazhigang Bridge and Jinjihe Bridge in Kunshan.The permeability and skid resistance data of the test roads are track monitored,and the performance of recycled asphalt before and after regeneration are tested.The test results indicate that the preventive maintenance technology based on penetrating regeneration can improve the road performance of asphalt pavement with sealing the surface cracks and reducing the permeability coefficients,and extend the service life of asphalt pavement with high economy.