Three-dimensional finite element model for flexible pavement analyses based on field modulus measurements.

Abstract

In accordance with the present development of empirical–mechanistic tools, this
paper presents an alternative to traditional analysis methods for flexible pavements
using a three-dimensional finite element formulation based on a linear-elastic
perfectly–plastic Drucker–Prager model for granular soil layers and a linear-elastic
stress–strain law for the asphalt layer. From the sensitivity analysis performed, it was
found that variations of ± 4° in the internal friction angle of granular soil layers did
not significantly affect the analyzed pavement response. On the other hand, a null
dilation angle is conservatively proposed for design purposes. The use of a Light
Falling Weight Deflectometer is also proposed as an effective and practical tool for
on-site elastic modulus determination of granular soil layers. However, the stiffness
value obtained from the tested layer should be corrected when the measured peak
deflection and the peak force do not occur at the same time. In addition, some
practical observations are given to achieve successful field measurements. The
importance of using a 3D FE analysis to predict the maximum tensile strain at the
bottom of the asphalt layer (related to pavement fatigue) and the maximum vertical
compressive strain transmitted to the top of the granular soil layers (related to rutting)
is also shown.