Dynamic Pavement‐Strain Histories from Moving Traffic Load

TLDR

Dynamic material properties of asphalt‑concrete layers vary with loading frequency. The study formulates and applies a continuum‑based finite‑layer model to evaluate dynamic pavement strains under moving traffic loads. The model’s predictive capability is demonstrated via a parametric study of thin and thick pavements subjected to a semitrailer at varying speeds. Pavement strains are strongly influenced by pavement thickness and vehicle speed, decreasing with higher speeds, and a substantial compressive strain at the bottom of the AC layer—up to a 1.01 compressive‑to‑tensile ratio in thick pavements under tandem axles—may be critical for fatigue life estimation.

Abstract

This paper presents the formulation and the application of a continuum‐based finite‐layer approach to evaluate dynamic pavement strains under 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 capability of the model is illustrated through a parametric study in which two typical thin and thick pavement sections were subjected to a semitrailer 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 and the vehicle speed, and they reduce substantially with the increase in the speed of the vehicle. Also, a substantial compressive‐strain component is present at the bottom of AC layer that may be important for any realistic fatigue‐life estimation of the pavement. The ratio between 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.