Effectiveness of Geosynthetics in Soil/Aggregate Stabilization—Evaluation Using Bender Element Sensor Technology

Wang, Han; Qamhia, Issam; Tutumluer, Erol; Kim, Youngdae

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https://hdl.handle.net/2142/128874 Copy

Description

Title

Effectiveness of Geosynthetics in Soil/Aggregate Stabilization—Evaluation Using Bender Element Sensor Technology

Author(s)

• Wang, Han
• Qamhia, Issam
• Tutumluer, Erol
• Kim, Youngdae

Issue Date

2025-06

Keyword(s)

• Geosynthetics
• Soil
• Aggregate
• Mechanical Stabilization
• Bender Element Sensor
• Small-Strain Modulus
• Finite Element Analysis

Date of Ingest

2025-06-25T10:49:36-05:00

Abstract

This report presents laboratory evaluations of the effectiveness of geosynthetics in stabilizing unbound aggregate layers and develops design guidelines for using geosynthetic-stabilized pavements in Illinois. The research focused on quantifying benefits from geosynthetic mechanical stabilization and incorporating those benefits into pavement analysis and design procedures. An experimental program was conducted, including laboratory triaxial testing and large-scale test bed evaluations. Twelve geosynthetic products, including ten geogrids (integral or punched and drawn, welded, and woven) and two geotextiles (woven and nonwoven), were tested. Six common aggregate materials were evaluated, including dense-graded aggregates (e.g., IDOT CA 6, CA 6/10, partially crushed gravel, recycled concrete aggregate) and open-graded aggregates (AASHTO No. 57, IDOT RR 01) with selected geosynthetics. Bender element sensor technology was used to quantify modulus enhancement due to geosynthetic inclusion through increased shear wave velocity measurements. The study found that geosynthetics can enhance the modulus of aggregate layers, and both integral and welded geogrids generally outperformed woven geogrids and geotextiles. Proper matching between geogrid aperture size and aggregate particle size was essential for achieving effective interlocking in open-graded materials. The zone of influence for geogrids to form a mechanically stabilized layer was typically about 4 in. The results were integrated into finite element analysis (FEA) models to simulate pavement layered structures and solve for the response behavior. The vertical deviator stress computed on a subgrade using FEA was typically reduced when a geosynthetic was present at the base-subgrade layer interface, indicating a response benefit. Design guidelines were developed to recommend reduced aggregate base thicknesses when geosynthetics are used. These guidelines are intended to update IDOT’s Subgrade Stability Manual and the Bureau of Local Roads and Streets Manual for Class IV low-volume roads. This study provided ready-to-use recommendations for geosynthetic selection and its benefits based on the laboratory quantification of modulus enhancement used in the mechanistic pavement analysis.

Publisher

Illinois Center for Transportation/Illinois Department of Transportation

Has Part

ISSN: 0197-9191

Series/Report Name or Number

FHWA-ICT-25-007

Type of Resource

text

Genre of Resource

technical report

Language

eng

DOI

https://doi.org/10.36501/0197-9191/25-007

Sponsor(s)/Grant Number(s)

IDOT-R27-234

Copyright and License Information

No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

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