DYNAMIC PAVEMENT-STRAIN HISTORIES FROM MOVING TRAFFIC LOAD

This paper presents the formulation and the application of a continuum -based finite-layer approach to evaluate dynamic pavement strains unde r moving traffic load. The dynamic material properties (complex shear modulus and Poisson's ratio) of the asphalt-concrete (AC) layer can be varied as a function of the loading frequency. The predictive capabil ity of the model is illustrated through a parametric study in which tw o typical thin and thick pavement sections were subjected to a semitra iler moving at different speeds. The results are very similar to those reported earlier from a field-testing program. The results show that the pavement strains are strong functions of the pavement thickness an d the vehicle speed, and they reduce substantially with the increase i n the speed of the vehicle. Also, a substantial compressive-strain com ponent is present at the bottom of AC layer that may be important for any realistic fatigue-life estimation of the pavement. The ratio betwe en the maximum compressive strain to the maximum tensile strain at the bottom of the AC layer can be as high as 1.01 for the thick pavements under tandem axles.