Document Type


Date of Degree

Spring 2013

Degree Name

MS (Master of Science)

Degree In

Civil and Environmental Engineering

First Advisor

Lee, Hosin

First Committee Member

Nixon, Wilfrid

Second Committee Member

Hanley, Paul


The main objectives of this research are to: 1) identify the most critical design input parameters, and 2) determine the minimum pavement thickness.

To minimize the life-cycle cost of building and maintaining pavements, it is critical to determine the most appropriate pavement material and thickness for a given traffic level, subgrade condition and environmental factor. The AASHTO 1993 guide for design of pavement structure is most commonly used by states for designing pavement thickness for low-volume roads. Statewide urban design and specifications (SUDAS) currently utilizes a simplified version of the AASHTO 1993 pavement design guide in Iowa, which is very conservative based on placement of the pavement on natural subgrade, distribution of truck classifications, and other design parameters. Therefore, there is a need for a modified pavement design methodology to be used for determining local road pavement thickness in Iowa.

A survey was performed to identify the minimum thicknesses of asphalt and concrete pavements and the pavement design methods for low-volume roads. The survey was completed by State DOT's. StreePave, WinPas, and I-Pave software packages were used to compare their impacts on the pavement thickness design.

The most critical input parameters were identified and their typical values for local roads in Iowa were used to run the existing StreePave, WinPas, and I-Pave pavement design software packages.


viii, 127 pages


Includes bibliographical references (pages 126-127).


Copyright 2013 Jeremy Purvis