Author : JK. Lindly
Publisher :
Page : 9 pages
File Size : 23,30 MB
Release : 1989
Category : Effective subgrade resilient modulus
ISBN :
Book Description
The research reported assessed a major change in the 1986 AASHTO Guide for Design of Pavement Structures. The soil support value was replaced with subgrade effective resilient modulus (MR) in flexible pavement design. MR was introduced into the 1986 AASHTO Guide as part of an overall shift to the use of elastic modulus as the indicator of pavement layer structural capacity. Because subgrade modulus changes when the subgrade moisture content changes or when the subgrade freezes, MR must reflect the combined effect of the modulus values from all seasons of the year. AASHTO suggests that the spring thaw modulus may be as low as 20 to 50% of the summer modulus.