Home Skip to main content

Research Reports
Report Details

Title:Resilient Modulus of Wyoming Subgrade Soils
Authors:Michael Farrar and John Turner
University:University of Wyoming
Publication Date:Jan 1991
Report #:MPC-91-1
Project #:MPC-005
TRID #:00639870
Keywords:clay, equations, fine grained soils, flexible pavements, forecasting, linear regression analysis, mathematical models, modulus of resilience, multiple regression analysis, pavement design, properties of materials, saturated soils, silts, soils, subgrade (pavements)
Type:Research Report – MPC Publications


This report describes a study to evaluate the use of subgrade resilient modulus for the design of flexible pavements. The objectives of this initial study were to: a) investigate the relationship between resilient modulus and R-value, and b) develop a predictive equation for resilient modulus based on easily measured soil properties. Thirteen different fine-grained soils were investigated. Based on the test results, two multiple linear regression models for predicting resilient modulus are proposed.

The principal result of this research is the development of improved equations for predicting the resilient modulus of silty and clayey subgrade soils in Wyoming. These equations yield the resilient modulus as a function of soil type, the state of stress in the pavement subgrade, the degree of soil saturation, R-value, and other soil properties. This study is the first to provide highway engineers in Wyoming with reliable information on the resilient modulus of representative subgrade soils. The information contained herein can be used by highway engineers to make informed decisions on how to incorporate the recommendations of the 1986 AASHTO Guide for Design of Pavement Structures into design methodology for highway pavements.

NDSU Dept 2880P.O. Box 6050Fargo, ND 58108-6050