Dynamic Modulus Back-calculation And Bearing Capacity Evaluation For Asphalt Pavement Structure

Research on the capacity of asphalt pavement structure is crucial. Highway traffic management will change to the mode of combination for both construction and maintenance, combination for management and conservation along with the more pragmatic of national policy, the progressive improvement of the road network, as well as transport integration and improved demands for the quality of service.The capacity evaluation of pavement is an important basis for the decisions of pavement maintenance. The Benkelman beam deflection method is not an effective means of compliance testing of pavement structure design, because the mechanical response of pavement structure under dynamic loading couldn’t be reflected by current method measured through Benkelman beam deflection, and the results is impact by environmental conditions and materials.Based on this premise, the following conclusions were drawn by the analysis of dynamic modulus of pavement structure layers, the analysis of pavement structural stress combined with new scientific test data and the assessment of the structural capacity for Jin-JI expressway. The pavement capacity evaluation which based on back calculation moduli of pavement structure of field is put forward. Each layer material of pavement structure is classified according to falling weight deflectometer(FWD) in testing environment of field and mechanical properties. Then, the regulation true value of dynamic modulus under the standard state is determined. It fills the gaps of missing discriminant value of dynamic modulus of material for road construction due to its great changing. The evaluation standard of dynamic modulus of material for road construction is proposed based on the measured temperature gradient and the frequency of FWD load, successfully eliminated the system error and prediction error. The judgment method which based on the equivalent of dynamic deflection is built. The asphalt pavement capacity evaluation which based on the judgment of composite modulus and the decay threshold value under fatigue load is proposed. Consequently, the poor accuracy of back calculation of structure layer and the missing problem of practical asphalt pavement capacity evaluation are solved.The research results have been applied on the design and construction of maintenance project for expressway pavement in Shanxi province, which could not only offer scientific basis for the conformance testing on pavement capacity of new road but also could give reasonable advice for the maintenance decision, treatment scheme and asphalt pavement capacity evaluation of old road. It’s application prospect is wide.