Synthesis/Literature Review for Determining Structural Layer Coefficients (SLC) of Bases.

摘要

FDOT’s current method of determining a base material structural layer coefficient (SLC) is detailed in the Materials Manual, Chapter 2.1, Structural Layer Coefficients for Flexible Pavement Base Materials. Currently, any new base material not approved under FDOT specifications must undergo (1) laboratory testing, (2) test pit investigation, and (3) a project test section for constructability and roadway performance evaluation to determine a SLC for design purposes. The test section evaluation phase can take up to five years to compare the pavement performance of the new base material with a limerock base control section. In this project, a thorough review of literature has been conducted of current and past practices for the determination of structural layer coefficients (SLC) of pavement base materials. The review organizes the methodologies into three broad categories: (1) methods that determine SLCs via relationships with other material parameters; (2) methods that determine SLCs via estimates of the structural number (SN) of existing and available pavement sections; and (3) methods that establish SLCs via equivalencies with a reference material. Several of the strategies reviewed provide opportunities for estimating SLCs of both traditional and new base course materials in a more accelerated fashion and in considerably less time than the five years often required at present.