Mechanistic Based Overlay Design Procedure For Washington State Flexible Pavements

Author : Haiping Zhou
Publisher :
ISBN 13 :
Total Pages : 385 pages
Book Rating : 4.:/5 (232 download)

DOWNLOAD NOW!

Download or read book Development of a Mechanistic Overlay Design Procedure for Flexible Pavements written by Haiping Zhou and published by . This book was released on 1990 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the development of a mechanistic overlay design procedure. The mechanistic analysis represents a new trend in both new pavement and overlay design. The greatest advantage of the mechanistic pavement analysis is that it considers the fundamental characteristics of materials to be used, is capable of considering changes in loading and tire pressure, and characterizes the response of the pavement to traffic loads in terms of strains and/or stresses. This type of analysis allows practicing engineers to more realistically address pavement structure, materials, and other influential variables such as environmental impacts so that the behavior of the pavement may be better understood. One of the critical steps in using the mechanistic type pavement analysis is the determination of pavement layer properties (e.g, resilient modulus). In this study, methods commonly used for determining resilient modulus have been reviewed. Three existing mechanistic overlay design procedures were also reviewed. Based on the review, improved procedures for determining pavement layer moduli and overlay design seem to be necessary. Significant contributions of this study are the development and computerization of an improved backcalculation procedure (BOUSDEF) for determining pavement layer moduli and an improved mechanistic overlay design procedure (MECHOD). Initial evaluations on both procedures were performed. For BOUSDEF, three approaches were used: 1) comparing with hypothesized theoretical moduli, 2) comparing with other developed backcalculation programs, and 3) comparing with laboratory tested modulus values. The evaluation showed BOUSDEF provided favorable comparisons. Therefore, the program can be effectively used as a tool to make initial evaluation of deflection testing data for determining pavement layer moduli. For MECHOD, actual pavement data from the states of Oregon and Alaska were used. All pavements evaluated are conventional structures consisting of an asphalt concrete surface, an aggregate base and/or a subbase, over subgrade. The evaluation showed that the improved method provided very similar results to those of standard procedures (ODOT, AASHTO, and The Asphalt Institute). The BOUSDEF and MECHOD programs can be implemented together as a pavement evaluation and overlay design system. That is; 1) use BOUSDEF to backcalculate pavement layer moduli, and 2) use MECHOD to perform overlay design.