Homogeneous versus Heterogeneous Response of a Flexible Pavement Structure: Strain and Domain Analyses

Abstract

This paper presents a computational model of a flexible pavement structure in finite elements (FE). The model is used to evaluate the response of a control (homogeneous) pavement structure, in contrast with equivalent random (heterogeneous) structures. One pavement structure is used as a control case, while 50 pavement structures with heterogeneous asphalt concrete (AC) layers are used in the random case. The AC layers in the random case exhibit spatially-varying mechanical properties; the instantaneous relaxation modulus (Eo) varies among the finite elements. AC variability propagated through the pavement layers. The uncertainty of critical responses was characterized, including longitudinal, transverse, shear, and vertical strains. The domain analysis (DA) method is applied to better understand the global (i.e., volumetric) response of the heterogeneous AC layers. Computational estimates of variability are presented, as predicted through the DA technique. Overall, for a fixed Eo variability, response variabilities ranked as follows: (1) near-surface shear strain in the AC layer presented the most variation relative to its magnitude, followed by (2) transverse and longitudinal strains (at the bottom of AC layer), and (3) vertical strains on top of base and subgrade. The results provide ranges of uncertainty for the new DA tool for the first time.