Laboratory Performance of Wicking Fabric H2Ri in Silty Gravel, Sand and Organic Silt

Laboratory Performance of Wicking Fabric H2Ri in Silty Gravel, Sand and Organic Silt

Connor, Billy; Zhang, Xiong

Date: 16-05

Subject: Geosynthetics (Rbmdxce) ; Unsaturated soils (Rbespmy) ; silts(Rbesgt) ; Sand (Rbesgs) ; Wicking Fabric

Type: Technical Report

Table of Contents: LIST OF FIGURES .........................................................................................................................v LIST OF TABLES ......................................................................................................................... vi CHAPTER 1 INTRODUCTION .................................................................................................1 CHAPTER 2 LITERATURE REVIEW ......................................................................................2 2.1 Adverse Effects of Subsurface Water in Pavement Design ........................................................... 2 2.2 Types and Sources of Subsurface Water....................................................................................... 5 2.3 Conventional Drainage Design Methods ...................................................................................... 5 2.3.1 Estimation of Inflow .............................................................................................................. 6 2.3.2 Estimate Drainage Capacity ................................................................................................ 10 2.4 Comparisons of Conventional and New Drainage Design Concepts .......................................... 11 2.5 Geosynthetic Application in New Drainage Design .................................................................... 12 2.6 Geotextile with Wicking Ability ................................................................................................... 14 2.7 Case Studies of Geotextile with Wicking Ability ......................................................................... 18 2.8 Potential Issues ........................................................................................................................... 25 CHAPTER 3 RELATIONSHIP BETWEEN SOIL SUCTION AND H2RI PERFORMANCE ..........................................................................................................................28 CHAPTER 4 TESTING FLUME SETUP .................................................................................30 CHAPTER 5 TEST RESULTS AND DISCUSSION ...............................................................35 5.1 Case 1: Wicking Test for Sand ..................................................................................................... 35 5.2 Case 2: Wetting Test for Sand ..................................................................................................... 37 5.3 Case 3: Rewicking Test for Sand .................................................................................................. 39 5.4 Case 4: Wicking Test for Silt ........................................................................................................ 41 5.5 Case 5: Rewicking Test for Silt .................................................................................................... 44 5.6 Case 6: 73‐foot Flume with E‐1 ................................................................................................... 46 5.7 Case 7: Introduction of Water at the Head of the Flume ........................................................... 52 5.8 Case 8: Estimating the Ability of Wicking Fabric to Wick Water ................................................. 56 CHAPTER 6 PROPOSED SPECIFICATIONS ........................................................................59 CHAPTER 7 SUMMARY AND CONCLUSIONS ..................................................................60 REFERENCES ............................................................................................................................62

Abstract:

The use of wicking fabric, H2Ri, is growing in its use to remove water from roadway and airport embankments. Past research has shown H2Ri to be effective in sands and fine grained materials in roadways up to 32 feet in width. However, there is a desire to use H2Ri for airports which require a minimum width of 75 ft. This project tested H2Ri in a 73-foot flume in a crushed surface course with 14 % fines. In addition, the fabric was tested in a 22-foot flume with a sand and with an organic clay. The intent was to bracket the material for which the H2Ri will work. The study showed that the fabric will easily move water 73 feet in a silty gravel. The study showed that the fabric was also able to readily remove water in sand. However, the fabric blinded when used in organic silt and proved ineffective. The study also showed that using simple overlap of the H2Ri as a splice, while effective, was not as efficient at moving water as the fabric itself. Consequently, moisture tended to build up around the splice.

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