Determination of Resilient Modulus Values for Typical Plastic Soils in Wisconsin

Determination of Resilient Modulus Values for Typical Plastic Soils in Wisconsin
Author: Hani Hasan Titi
Publisher:
Total Pages: 316
Release: 2011
Genre: Pavements
ISBN:

The objectives of this research are to establish a resilient modulus test results database and to develop correlations for estimating the resilient modulus of Wisconsin fine-grained soils from basic soil properties. A laboratory testing program was conducted on representative Wisconsin fine-grained soils to evaluate their physical and compaction properties. The resilient modulus of the investigated soils was determined from the repeated load triaxial (RLT) test following the AASHTO T307 procedure. The laboratory testing program produced a high-quality and consistent test results database.

Engineering Properties Affecting the Resilient Modulus of Fine-grained Soils as Subgrade

Engineering Properties Affecting the Resilient Modulus of Fine-grained Soils as Subgrade
Author: Dong-Gyou Kim
Publisher:
Total Pages: 338
Release: 1999
Genre:
ISBN:

Ohio soils used as subgrade soils for a road were studied to evaluate parameters affecting resilient modulus. The dominant Ohio soils could be classified in one of three AASHTO Soil Classification system groups, A-4, A-6, and A-7. Laboratory tests were performed on the cohesive soils to measure Atterberg Limits, particle size, optimum moisture content, maximum dry density, and unconfined compressive strength. The resilient modulus tests were conducted on each sample compacted at the dry of optimum, optimum, or wet of optimum moisture content. The measured resilient modulus for each soil sample was analyzed to evaluate the effect of stresses and engineering indexes. Three different models to predict the resilient modulus using engineering indexes were used to compare the measured resilient modulus. The confining stress affected the resilient modulus. The resilient modulus decreased with an increase in the deviator stress, and linearly increased with an increase in the percent of silt and clay and maximum unconfined compressive strength. The increase in moisture content considerably affected the decrease in the resilient modulus. The resilient modulus predicted using the three models showed a large variation with the resilient modulus measured.

Factors Influencing the Determination of a Subgrade Resilient Modulus Value

Factors Influencing the Determination of a Subgrade Resilient Modulus Value
Author: Khaled Ksaibati
Publisher:
Total Pages: 38
Release: 1993
Genre: Pavements
ISBN:

This report describes a study jointly conducted by the University of Wyoming and the Wyoming Department of Transportation to examine the factors influencing the determination of a subgrade resilient modulus value. The objectives of this study were to first, investigate the importance of several fundamental soil properties in determining a design subgrade resilient modulus value; and second, to define the actual relationship between back calculated and laboratory based resilient modulus values for typical cohesive subgrade soils in Wyoming. This study consisted of selecting nine test sites with cohesive subgrade soils in the state of Wyoming, conducting laboratory testing on subgrade cores obtained in 1992 and 1993, determining several fundamental soil properties on these cores, and using deflection data from these nine sites to determine resilient modulus values from three back calculation programs. The data analysis resulted in several important conclusions about factors that influence the selection of a design subgrade resilient modulus value.

Resilient Modulus Prediction Employing Soil Index Properties

Resilient Modulus Prediction Employing Soil Index Properties
Author:
Publisher:
Total Pages: 64
Release: 2004
Genre:
ISBN:

Subgrade soil characterization in terms of Resilient Modulus (MR) has become crucial for pavement design. For a new design, MR values are generally obtained by conducting repeated load triaxial tests on reconstituted/undisturbed cylindrical specimens. Because the test is complex and time-consuming, in-situ tests would be desirable if reliable correlation equations could be established. Alternately, MR can be obtained from correlation equations involving stress state and soil physical properties. Several empirical equations have been suggested to estimate the resilient modulus. The main focus of this study is to substantiate the predictability of the existing equations and evaluate the feasibility of using one or more of those equations in predicting resilient modulus of Mississippi soils. This study also documents different soil index properties that influence resilient modulus. Correlation equations developed by the Long Term Pavement Performance (LTPP), Minnesota Road Research Project, Georgia DOT, Carmichael and Stuart, Drumm et al., Wyoming DOT, and Mississippi DOT are studied/analyzed in detail. Eight road (subgrade) sections from different districts were selected, and soils tested (TP 46 Protocol) for MR in the laboratory. Other routine laboratory tests were conducted to determine physical properties of the soil. Validity of the correlation equations are addressed by comparing measured MR to predicted MR. In addition, variations expected in the predicted MR due to inherent variability in soil properties is studied by the method of point estimates. The results suggest that LTPP equations are suited for purposes of predicting resilient modulus of Mississippi subgrade soils. For fine grain soils, even better predictions are realized with the Mississippi equation. A sensitivity study of those equations suggests that the top five soil index properties influencing MR include moisture content, degree of saturation, material passing #200 sieve, plasticity index and density.