Development of a Design Method for H2Ri Wicking Fabric in Pavement Structures

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Author
Lin, Chuang
Zhang, Xiong
Han, Jie
Keyword
Geotextiles
Subsurface Drainage
Unsaturated Soils
Capillarity
Embankments
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URI
http://hdl.handle.net/11122/10398
Abstract
A new roadway drainage design concept is proposed to reduce the roadway water content and enhance the overall pavement performance by implementing H2Ri geotextile with lateral wicking ability. Compared with conventional drainage materials, this type of geotextile has high tensile strength and higher specific surface area, which enable to continuously transport water under unsaturated conditions. SEM (Scanning Electron Microscope) images indicated that the geotextile functions effectively for soils with particle size larger than 12 microns. A series of tests were performed to establish the relationships among different parameters, including resilient modulus test, large-scale direct shear test, salt concentration test and pressure plate test. Test results indicated that the soil-geotextile system can work effectively to reduce the water content within the pavement structure by 2%. By doing so, the corresponding resilient modulus can be increased by 3 times and the permanent deformation can be reduced to half of that value. Meanwhile, the interface frictional strength between geotextile and soil was not sensitive to water content change.
Table of Contents
DISCLAIMER................................................................................................................................ I ACKNOWLEDGMENTS .......................................................................................................... III TABLE OF CONTENTS ........................................................................................................... IV LIST OF FIGURES .................................................................................................................... VI LIST OF TABLES ................................................................................................................... VIII EXECUTIVE SUMMARY .......................................................................................................... 1 CHAPTER 1.0 INTRODUCTION .............................................................................................. 3 1.1 Problem Statement ........................................................................................................ 3 1.2 Research Objectives ...................................................................................................... 4 1.3 Research Methodology ................................................................................................. 4 CHAPTER 2.0 LITERATURE REVIEW .................................................................................. 7 2.1 Water Sources in Pavement Structures ......................................................................... 7 2.2 Detrimental Effect of Water on Pavement Performance .............................................. 8 2.3 Conventional Drainage Design Methods and Traditional Geotextile Applications ... 13 2.4 A Geotextile with Wicking Ability for Unsaturated Water Drainage ........................ 18 2.5 Potential Issues and Concerns ..................................................................................... 26 CHAPTER 3.0 MATERIAL CHARACTERIZATIONS ........................................................ 28 3.1 Soil Properties ............................................................................................................. 28 3.2 Resilient Modulus Test ............................................................................................... 29 3.3 Pressure Plate Test and Salt Concentration Test......................................................... 39 3.4 H2Ri Geotextile Air Entry Value Determination ....................................................... 48 3.5 Unsaturated Soil Hydraulic Conductivity ................................................................... 51 v 3.6 Large Direct Shear Test .............................................................................................. 56 CHAPTER 4.0 GEOTEXTILE WORKING MECHANISM AND POTENTIAL ISSUES 63 4.1 H2Ri Geotextile Working Theoretical Range............................................................. 63 4.2 Soil-Geotextile System Working Mechanism ............................................................ 64 4.3 Potential Issues............................................................................................................ 71 CHAPTER 5.0 CONCLUSIONS AND RECOMMENDATIONS ......................................... 93 REFERENCES ............................................................................................................................ 96 APPENDIX A BASIC PROPERTIES FOR AB3 BASE COURSE ..................................... 105 APPENDIX B RESILIENT MODULUS TEST ..................................................................... 106 APPENDIX C SWCC AND GWCC TEST RESULTS ......................................................... 113 APPENDIX D LARGE-SCALE DIRECT SHEAR TEST ................................................... 117
Date
2016-11
Type
Technical Report
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