A Pavement Design and Rehabilitation System

Abstract

Because the Superpave system is not readily available for use, an interim pavement design and rehabilitation method was developed that can be used for Israeli traffic and environmental conditions. The existing method was upgraded to include most of the relevant available information and to produce reliable pavement design for the specific conditions in Israel. The upgrading concentrated on multiple topics. An axle-load distribution specific to Israeli conditions was included because analysis indicates that axle loads in Israel are typically above the standard 80-kN single axle load. The extended California bearing ratio (CBR) method was adapted to a variety of axle-load combinations by using Miner's law for damage accumulation. Converting the axle-load distribution to the standard 80-kN equivalent single axle load leads to underdesign of approximately 10 percent in pavement thickness (or to a reduction of about 70 percent of the design life). A fatigue consideration to determine the asphalt-layer thickness was added. Local temperatures were analyzed to determine an equivalent temperature for fatigue calculation. For Israeli conditions, an equivalent temperature of 14°C can be used countrywide for asphalt-layer thicknesses up to 250 mm. An overlay design method consistent with the upgraded design procedure was assembled. It includes backcalculation of layer moduli to determine the subgrade CBR and the quality of the pavement layers; pavement condition surveys to evaluate a representative effective thickness of the asphalt layer; and component-layer analysis to determine the overlay thickness.