Research On Asphalt Pavement Structural Health Evaluation Method Based On Non-destructive Testing Technology

The smooth operation of highway maintenance is a necessary condition for the sustainable development of expressway.Reasonable evaluation of asphalt pavement technology is the key and prerequisite for the asphalt pavement maintenance work to be carried out.Asphalt pavement maintenance practice previously stated that the technical status of the evaluated asphalt pavement can be roughly divided into road surface health and structural health.The detection and evaluation methods of asphalt pavement surface health status have become increasingly mature,but for the detection and evaluation methods of internal structural health status need to be further studied.In this paper,3D ground penetrating radar(GPR)with 3 dimensional detection of the internal structure of asphalt pavement and FWD with internal mechanical responses detection of asphalt pavement structures are used to evaluate the structural health of the asphalt pavement.The internal structural integrity of asphalt pavement and the mechanical strength of the asphalt pavement structure are comprehensively evaluated from the macroscopic visual disease detection and damage degree determination and the asphalt pavement bearing capacity calculation.In chapter 1,the concept of structural health status of asphalt pavement based on flexible pavement design theory is expounded,and the research of pavement structure health status by 3D GPR and FWD is introduced in detail,including asphalt pavement structural damage detection and road structure bearing capacity checking.In chapter 2,the basic theory of electromagnetic wave,the system composition of 3D GPR and its selection principle of detection parameters introduced.The principle of asphalt pavement thickness measurement and the electromagnetic wave reflection characteristic of the internal structure disease are analyzed,and the pavement structure thickness and structural disease identification method of 3D radar are clarified.In chapter 3,based on the theory of multi-layer elastic system,the influence of pavement structure modulus on deflection basin is studied statistically.The similarity between the deflection curve and the sigmoid curve is analyzed by probability density concept.The influence of pavement condition level on the similarity is also studied.On this basis,the asphalt pavement structural parameter inversion method based on FWD deflection basin and large data analysis method is proposed and demonstrated.The rationality of the inversion result is analyzed from three aspects of pavement structure difference,temperature difference and load difference.In chapter 4,the pavement structure thickness and structural damage detection by 3D GPR are carried out.The three-dimensional damage rate of asphalt pavement is proposed,and the structural health index of asphalt pavement based on 3D GPR is further proposed.In chapter 5,the asphalt pavement deflection basin is tested synchronously,and the pavement modulus and stiffness coefficient are retrieved.The asphalt pavement modulus is obtained by inverting the stiffness coefficient and the thickness data detected by 3D GPR,and then the bearing capacity of each pavement layer is verified.Therefore,it is verified whether the bearing capacity of each structural layer is sufficient with the inversion modulus and cal-modulus respectively.Finally,an assessing system for asphalt pavement structural health based on 3D GPR and FWD is established,which provides a new method for evaluating the structural health of asphalt pavement quickly,efficiently and comprehensively.