Evaluating Influence of Thickness and Interface Bonding on Overlay Service Life Using 3D FEM

Abstract

The use of structural and nonstructural overlays has gained popularity in recent years due to financial and environmental constraints; however, the impact of overlay thickness and the type of applied tack coat on induced strains, where overlay interfaces with an existing surface layer, has not yet been extensively evaluated. In this study, the three-dimensional (3D) finite-element modeling technique was used to evaluate existing pavements of varying thicknesses with various overlay thicknesses, and different interface bonding strengths that were modeled in Abaqus. The results of this study verify that the impact of interface bonding strength on the overlay durability and structural characteristics of pavement changes drastically by changing the overlay thickness. For nonstructural overlays with a thickness of 12.7 mm (0.5 in.) or 25.4 mm (1 in.), interface bonding strength (tack coat) was found to play a prominent role in overlay durability, whereas overlay thickness was found to have a negligible impact. Increasing the thickness of the overlay from 25.4 mm (1 in.) to 50.8 mm (2 in.) significantly decreased the impact of interface bonding strength, whereas the influence of overlay thickness increased.