Study On The Modulus Of Semi-rigid Basic Structure Of End-servicing Pavement

Above80%high-level highways which are constructing or completed are semi-rigid asphalt pavement structure in china, Some highways of semi-rigid asphalt pavement structure have appeared premature failure because of the construction, overloaded vehicles and its own destruction, resulting in the decreased life of the pavement from15-20years to5-8years. With the continuous increase of the servicing time, most of the semi-rigid asphalt pavement have been in the end-servicing state, its structure modulus status and road performance gradually decay under the action of vehicle load and natural environment, it is necessary to study the modulus of semi-rigid base structure, for providing the reference of the medium and large repair and maintenance.Based on the existing research results of laboratory test and the analysis results of deflection basin data at home and abroad, this paper study the modulus of semi-rigid base structure of the end-servicing pavement from indoor semi-rigid base material modulus parameters, structural damage state bent under heavy response and pavement modulus.First, under the learning of the dynamic modulus test methods at home and abroad, this paper proposes the testing methods of dynamic indirect tensile modulus, dynamic compressive modulus of elasticity and dynamic bending elasticity modulus according to the different styles of the force. By repeating the indoor load dynamic modulus test, this paper analyzes and compares the modulus state and the flexural tensile stress state of semi-rigid base material between the material is initial and serious injury.Secondly, through gathering the data of deflection rut, net crack, pits and other characterized diseases points and combining the theoretical analysis, this paper studys the damage status and bearing capacity of the feature points of each layer damage status. At the same time, according to different positions from the road cracks table FWD deflection basin parameters were analyzed, this paper puts forward the deflection basin parameters and the relationship between the pavement diseases and the basis of evaluating damage status inside the pavement structure, providing the reference to the detailed analyses of current situation of the internal structure by developing FWD testing means.Finally, the deflection basin of layers damage road data are obtained through milling and FWD tests on the top surface layers location of the end-servicing pavemen. With the deflection basin data of layer modulus back calculation of each structure based on the theory of elastic layered system, this paper puts forward the modulus and parameters of semi-rigid structures of end-servicing pavement combining material parameters of damage state and pavement structure response state.