Mechanistic response of conventional vs perpetual flexible pavements under similar loading condition : a 3-d finite element analysis

Abstract

A 3D finite element analysis was conducted on several models of conventional and perpetual pavements to assess the similarities and differences in their structural and fatigue response when both pavement types are subjected to varied axle load and wheel configurations. The models were designed as a five-layer pavement system made up of an asphalt surface laid on an asphalt binder course. The base used was a graded crushed stone of G1 quality. Asphalt materials were assumed to be viscoelastic, while the granular base, subbase and subgrade were assumed to be linearly elastic. All material properties conformed to the South African Mechanistic Design Method (SAMDM) Guideline. Tandem axle dual wheel loading produces the least safety factor and fatigue life, and the highest damage among other configurations. Perpetual pavement models from the same materials were found to be more structurally rigid when comparing strains and damage in the long term. They show more resistance to distress by traffic loading when compared to conventional pavements. It was concluded that a 3-Dimensional Finite Element Analysis (FEA) is a suitable tool for supporting Mechanistic-Empirical design methods and provides a platform for further investigation of the behaviour of perpetual pavements.