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Corresponding Author

Sakr, Hazem

Subject Area

Civil and Environmental Engineering

Article Type

Original Study

Abstract

The influence of variations in asphalt t concrete mix properties on pavement performance during Its life is a critical factor in highways construction. Although other pavement's layers; base course, subbase and subgrade have also important effect on performance: however, they can easily be adjusted early during the construction. Shortly after being laid the asphalt concrete surface layer hardens; therefore, no adjustment can be applied. An asphalt concrete surface layer can be characterized by its percent air voids, percent asphalt con tent, asphalt properties, percent filler and aggregate type and gradation. Quite often material quality does not meet specification requirements. The effect of this nonconformation on the pavement serviceability has not been established; however, it results in reduced payments to contractors. The pay adjustment methods currently used in Egypt is based mainly on discounting the present cost of materials lost out of the mix from the contractor's payment. This method of penalizing the contractor is not based on sound engineering principles. Thus, it is not always a reliable measure of pavement's reduced serviceability. The purpose of this study is to develop a pay adjustment method that is based on the actual serviceability of pavement. It was based on the serviceability of pavement defined in the ASSHTO method of thickness design. It was assumed that the maximum penalty a contractor can ever pay was equivalent to an adjusted cost of an overlay which upgrads the pavement to its design serviceability. The actual penalty wa5; then, computed based on the actual loss of serviceability experienced over time. Summary tables and figures that facilitate presenting the method and its application through a simple example are included.

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