Abstract Manager

Accurate material constitutive relations are an essential component of any continuum mechanistic road model which enables road engineers to reliably predict road structural primary response and therefore performance prediction of various road assets.  The material constitutive relations used in modeling must represent the full spectrum of mechanical behavior across three-dimensional stresses and strains experienced in realistic field state conditions.  These primary response profiles are necessary to predict the sensitivity to failure modes of each road structural layer interactively within the road structural system.    

This paper demonstrates the use of MEPDG AASHTO T307 and PSIMaterials3D triaxial frequency sweep complex modulus characterization of typical Saskatchewan road materials (neat and recycled).  These material constitutive properties were encoded in three-dimensional numerical modeling PSIPave3D representing typical highway and urban street structures under realistic field load and climatic state conditions.   

This study shows, the MEPDG AASHTO T307 unbound road material testing protocols are severely limited to capture the full spectrum of material constitutive behavior across typical Saskatchewan field state conditions as compared to the PSIMaterials3D complex modulus triaxial frequency sweep characterization performed on the same materials.   The material constitutive properties obtained from PSIMaterials3D were found to represent a broader spectrum of typical road design scenarios often encountered for by road engineers, particularly under heavy non-linear loading, high viscoelastic behavior, and urban field state conditions compared to MEPDG AASHTO T307.