Remaining-life consideration in pavement overlay design

Abstract

The thickness deficiency-based approach is a widely used procedure for pavement overlay design. There is a need to incorporate a remaining-life consideration into this approach. The traditional 1986 AASHTO's equations produce equations do not include this consideration. The 1986 AASHTO procedure introduced a remaining-life factor in its overlay design equations. While its concept of remaining life consideration is fundamentally correct. AASHTO's equations produce inconsistencies in overlay designs due to an inadequacy in the formula used for calculating the remaining-life factor. A new expression for the remaining-life factor is derived in this paper. It is shown that the traditional and the AASHTO design equations are special cases of this new expression. The salient features of the derived expression are described. A design procedure based on the new equations is proposed. Numerical examples are presented to demonstrate the applications of the proposed procedure.