The Research On Equipment For Detecting Strength Of Shallow Asphalt Pavement Under Freezing

In the south of China, the destruction of the road due to freezing are popular, especially serious in the plateau area of YunGuiChuan. The problem people care about is how difficult the road suffered damage by freezing. At present, there have been not a simple and convenient detection method for the strength of shallow asphalt pavement under freezing.To test and evaluate the strength of asphalt pavement which have been damaged by freezing, this paper has developed a simple, convenience and relatively precise equipment—Strength Detector of Shallow Asphalt Pavement.First of all, Strength Detector of Shallow Asphalt Pavement is designed based on the impact and penetration principle, namely the hammer free drops from a certain height and hammers the probe, make it penetration the pavement a certain depth. The operation principle of Strength Detector of Shallow Asphalt Pavement is simulated through the finite element method. According to the simulation results, different quality hammer and different diameter probe are preliminary analyzed and screened. Considering characteristics of Strength Detector of Shallow Asphalt Pavement and the asphalt pavement structure, the 10kg hammer and 8mm in diameter probe are chose on the basis of the paper analyzes the discreteness of testing;Second, designing the different air void to control the changes of the mechanical performance of asphalt mixture specimens, which need impacting and penetration test, the uniaxial compression test and the fracturing test. According to the results getting the relationship of average penetration depth and compressive strength, fracture tensile strength of the asphalt mixture. At the same time, making the impacting and penetration test for asphalt mixture specimens which have been in the different freeze-thaw cycles, to get the relationship of average penetration depth and fracture tensile strength. Finally, building the reference standard for the test of Strength Detector of Shallow Asphalt Pavement.Finally, detecting to the core samples of asphalt pavement of ChongZun highway in GuiZhou province, and getting the compressive strength and fracture strength of core samples by the reference standards. Thereby evaluating the extent to damage of asphalt pavement of ChongZun highway.