Feasibility of whitetopping pavements for resurfacing thin asphalt pavements

Abstract

Many asphalt pavements have experienced rutting (wheel path deformation) while many others have experienced cracking. One of the possible solutions to this problem is the use of whitetopping, which is a composite section with a concrete layer over an existing asphalt pavement. Whitetopping has an advantage over an asphalt overlay in that the concrete surface is stronger and thus is more resistant to rutting and surface-initiated cracking. This research attempts to study the feasibility of whitetopping for resurfacing of thin asphalt pavements (less than 100 mm) in tropical and sub-tropical countries. Whitetopping pavement test track constructed at the acceleration testing facility in a tropical climate, at the Florida Department of Transportation (FDOT), was used for the study. A three-dimensional (3-D) finite element model (FEM) was developed to simulate the field conditions using SAP2000 structural analysis software. The developed model was verified with field measured strain data. The verified analytical model was used to perform a parametric study in order to find the sensitivity and effects of loading conditions, joint spacing, joint conditions, whitetopping thickness, asphalt thickness, interface bond between asphalt and whitetopping, elastic modulus of concrete and asphalt, base and subgrade layers and temperature differentials in concrete. This study found that the developed model can be used to estimate the maximum anticipated stresses in whitetopping pavements. The research revealed that ultra thin whitetopping pavement (less than 50 mm thick) is not suitable for resurfacing of thin asphalt pavements. A minimum concrete thickness of 60 mm and 80 mm is required for a 80 mm asphalt thickness with a joint spacing of 0.9 m for axle load controlled at 80 KN (18 kips) and 98 KN (22 kips), respectively. The parametric study revealed that the minimum thickness needs to be adjusted with other design parameters.