INNOVATIVE DESIGN STRATEGY INCORPORATING TEMPERATURE EFFECT ON THE PENNSYLVANIAN PAVEMENTS

Abstract

The effect of problematic soils and temperature on the asphalt concrete layers suitable for Pennsylvanian conditions on the design of pavements as applied to the state of the art design procedure have not been studied. Temperature has exponential effect on the asphalt stiffness. Asphalt stiffness has also exponential effect on the layer thickness. This study focuses on these important effects for the specific range of materials and environmental conditions that prevail in the state. The objective of this research is to develop an innovative design strategy capable of handling the temperature variations in the asphalt concrete layers. This strategy handles weak soils specific to Pennsylvania using a wide variety of variables consisting of standard deviations, traffic, MR, Delta PSI, surface course, base course and sub base materials. For all designs, the surface course and the base course contain minimum thicknesses as a function of traffic. The efficacy of expansive soil-limestone as sub base material was evaluated by designing and estimating a flexible pavement thicknesses. The modified strength coefficients were used for designing the pavement sections in Pennsylvania. Based on this research, it can be concluded that the sub base thickness has (i) a linear relationship with the structural number, and (ii) a nonlinear relationship with the change in serviceability index and the resilient modulus. In this innovative design strategy, the effect of temperature is built into the structural number. This is achieved by appropriately modifying the strength coefficient for the asphalt concrete layer.