Study On Attenuation Law And Backcalculation Methods Of Semi-rigid Pavement Structure Layer Modulus

Semi-rigid pavement performs as the main highway pavement structure form. Because semi-rigid base possesses good compression property but its tensile performance is inferior, crack strain of semi-rigid base under fatigue load has important control function to the durability of rigid pavement structure. Studying the decay rule of flexural resilience modulus value and mastering the pavement dynamic state of semi-rigid base in operation are of great theoretical significance to determination of base parameter in the semi-rigid pavement structure design.Combining with the " Asphalt pavement design method research based on the multiple indexes" subject research, and through the Shandong province perpetual pavement entitative engineering, the reasonable structure layers division method to the different asphalt pavement in the backcalculation process was analyzed systematically; The reliability of modulus backcalculation to pavement structure layers by utilizing MODULUS、SIDMOD and ERERCALC modulus backcalculation software was investigated; By the full scale pavement accelerating load testing section of three kinds of semi-rigid base pavement structure, deflection and modulus variation law of semi-rigid pavement structure in the different ages was studied; Through the accelerating load testing, the relationship among the loading times and tensile strain of the asphalt layer and base bottom, compressive stress of subgrade top, pavement deflection and other pavement dynamic response index was analysed systematically, and decay rule of road surface rebound deflection and flexural-tensile modulus to inorganic binder stable class base pavement structure in the using process was investigated systematically.Based on the study, the reasonable division method of different asphalt pavement structure layers in the backcalculation process was proposed, and the asphalt layer division method according to the temperature gradient of pavement structure layer was determined; The SIDMOD for modulus backcalculation software of the semi-rigid pavement based on the iteration method was concluded; Deflection and modulus variation law of semi-rigid pavement structure in the different ages was conducted; The relationship among the loading times and tensile strain of the asphalt layer and base bottom, compressive stress of subgrade top, pavement deflection and other pavement dynamic response index was obtained; Decay rule of deflection and modulus for inorganic binder stability base in the using process was put forward, and the linear relationship equation between the loading times and base modulus of different semi-rigid pavement structure was obtained.