Research On Mechanical Properties And Applicability Of Cold Patch Asphalt Mixture

Pothole disease is one of the most common diseases of asphalt pavement.In order to ensure the service life of asphalt pavement and the safety and comfort of drivers,it is necessary to repair the pothole in time.As a new road repairing material,cold repairing asphalt mixture can achieve the purpose of "immediate repair,and immediate open the traffic" when repairing potholes.It is less limited by climate,smokeless and environmentally friendly when paving.At present,a great deal of research has been done on raw materials,production processes and test methods of cold patch asphalt.The performance of cold patch asphalt mixture has been evaluated through laboratory tests in terms of material characteristics,construction and workability,initial strength and forming strength of the mixture.The asphalt mixture is still in a soft state at the beginning of application,and it has a size limit when applied to pit repair.If the size is too large,the road surface may be damaged due to insufficient strength.However,in the existing literature,there are few researches on the repair size of cold-filled asphalt mixture during pothole repair,and the mechanical properties are not measured,which limits the promotion and application of cold patch asphalt mixture.In view of the above problems,the studies and designs of the cold repairing asphalt mixture.By defining the technical requirements of cold patch asphalt mixture,the main design points of current cold patch asphalt mixture are obtained.The gradation and asphalt dosage of cold patch asphalt mixture were determined through the experiments of adhesion and cohesion of cold patch asphalt mixture.In order to improve the quality of cold patch asphalt mixture,ensure the repair effect of potholes and the durability of repaired potholes,the production process of cold patch asphalt mixture was put forward.Secondly,the mechanical properties of cold patch asphalt mixtures were tested through experiments,and the mechanical properties data were obtained,which provided parameters for finite element simulation of pothole repair.In order to simulate the state of cold patch asphalt mixture which has existed for several months in actual road repair,the cold patch asphalt mixture is placed into oven to accelerate aging,and the stability of cold patch asphalt mixture is increased.By comparing and analyzing several commonly used modulus determination methods,the indirect tensile test was selected to measure the modulus of cold patch asphalt mixture.The indirect tensile test specimens were formed by Marshall compaction method,and the height of the specimens was determined.The modulus of cold patch asphalt mixture was obtained through specific test.In order to measure the shear strength of cold patch asphalt mixture,uniaxial penetration test and unconfined compressive strength test were used.The specimens of shear strength test were formed by static pressing method,and the size and loading speed of the specimens were determined.The shear strength,internal friction angle and cohesion of cold patch asphalt mixtures with two different asphalt contents were measured by tests.Finally,the theoretical model and calculation system of mechanics calculation of asphalt pavement are analyzed,the basic model structure of pothole repairing pavement structure is defined,and the simulated size of pavement structure and wheel load are determined.According to the damaged area and depth of pothole groove in asphalt pavement,pothole groove is divided into mild damage,moderate damage,serious damage and serious damage.The effect of wheel on pothole groove after actual road repair is analyzed,and the load action is divided into six kinds according to the location of wheel load action.According to the stress change and maximum displacement of different position of automobile,the most disadvantageous load position of cold repairing asphalt mixture patch is determined.The mechanical responses of three different pothole sizes and three different pothole depths of cold repairing asphalt mixture in the most unfavorable position are analyzed.The matching relationship between pothole depth and plane size is obtained,and the optimum application range is determined.Through this study,on the basis of mechanical analysis and finite element simulation,it provides theoretical support for the applicability of cold patch asphalt mixture,provides technical support for road pothole repair work,and puts forward systematic evaluation methods to provide a standard concept for future pothole repair technology,which is conducive to the vigorous development of road undertakings,and has good significance and prospects.