Graduation Semester and Year
Spring 2026
Language
English
Document Type
Thesis
Degree Name
Master of Science in Civil Engineering
Department
Civil Engineering
First Advisor
Dr. MD Sahadat Hossain
Second Advisor
Dr. Xinbao Yu
Third Advisor
Dr. Warda Ashraf
Abstract
Expansive soils inflict an estimated nine to fifteen billion dollars in annual damage to infrastructure across the United States, surpassing the combined losses from earthquakes, floods, hurricanes, and tornadoes (Nelson and Miller, 1997; Jones and Jefferson, 2012). In Texas, eighteen of twenty-five TxDOT districts contend with pavement failure rooted in moisture-driven volume change of subgrade clay, consuming roughly twenty-five percent of the agency's annual budget for maintenance and repair (Sebesta, 2002; Wanyan et al., 2010). Conventional remediation approaches, including soil replacement, chemical stabilization with lime or cement, and prewetting, are either prohibitively expensive, unsuitable for high-sulfate soils, or confined to surficial treatment that fails to address the underlying moisture mechanism (Snethen, 1979; Mitchell and Dermatas, 1992).
This thesis presents a multi-site field evaluation of Modified Moisture Barrier (MMB) systems for subgrade stabilization of flexible pavements on expansive soils in North Texas. The MMB, comprising a geocomposite drainage layer underlain by an impermeable LLDPE geomembrane at the base–subgrade interface, intercepts downward-percolating rainwater and channels it laterally to the pavement edge while completely isolating the subgrade from vertical infiltration. Two TxDOT installations were monitored: the Dallas site (FM 1836, Kaufman) with Lean Clay (CL) subgrade over thirty months, and the Fort Worth site (FM 1884, Weatherford) with Clayey Sand (SC) subgrade over twenty months. Both sites were instrumented with moisture and suction sensors at multiple depths, horizontal inclinometers, and periodic electrical resistivity imaging (ERI) surveys.
At Dallas, the barrier section exhibited a maximum moisture deviation of only 0.5% compared to 4.2% in the control, suction remained within a 1.1 kPa range versus 9.1 kPa in the control, vertical deformation was reduced by sixty-two percent, and zero surface cracks appeared through thirty months while the control cracked at twenty-four months. At Fort Worth, all monitored sections maintained stable moisture profiles independent of rainfall, and monthly ERI surveys confirmed consistently higher resistivity beneath the barrier relative to the unprotected control. These multi-site results, spanning two distinct soil classifications and multiple seasonal cycles, demonstrate that MMB is a cost-effective, sustainable, and readily deployable solution, and strongly supports its wider adoption across TxDOT districts.
Keywords
Modified Moisture Barrier (MMB), expansive soils, pavement distress, subgrade stabilization, geocomposite, geomembrane, volumetric moisture content, suction pressure, horizontal inclinometer, electrical resistivity imaging (ERI), flexible pavement, North Texas
Disciplines
Civil Engineering
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Shahriar, MD Tamim, "Performance Evaluation of Modified Moisture Barrier for Subgrade Stabilization of Pavements on Expansive Soils" (2026). Civil Engineering Theses. 2.
https://mavmatrix.uta.edu/civilengineering_theses2/2