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Sec. 1.2 Overview of Geotextiles . 5 <br />the engineer, manufacturer, andor contractor. The application areas are numerous and <br />growing steadily. The major functions encompass the entire gambit of functions listed <br />for the geosynthetics discussed previously: <br />1. Separation <br />2. Reinforcement <br />3. Filtration <br />4. Drainage <br />5. Moisture barrier <br />These geocomposite functions, tied intimately to their respective application areas, form <br />Chapter 5. <br />Chapter 6 concludes the book and offers a number of appendices. These include <br />conversion tables (the book is primarily in English units), a glossar>' of geosynthetic <br />terms, polymeric structure of the more commonl> used materials, and a list of current <br />geosynthetic manufacturers, styles, and related properties. <br />1.2 OVERVIEW OF GEOTEXTILES <br />1.2.1 HistOf7 <br />Geotextiles, as known and used today, were first used in connection with erosion control <br />applications and w'ere intended to be an alternative for granular soil filters. Thus the <br />original, and still sometimes used, term for geotextiles was “filter fabrics.” Barrett [4 <br />(in his now classic 1966 paper) tells of work originating in the late 1950s of using geo ­ <br />textiles behind precast concrete seawalls, under precast concrete erosion control blocks, <br />beneath large stone riprap, and in other erosion control situations. He used different <br />styles of woven monofilament fabrics, all characterized by a relatively high percentage <br />of open area (varying from 6 to 30%). He clearly discussed the need for both adequate <br />permeability and soU retention, along with adequate fabric strength and proper elonga ­ <br />tion. Barrett indeed set the tone for geotextile use in filtration situations. Note should be <br />made that a paper by Agerschou [5] discussed applications along the same general lines. <br />In the late 1960s Rhone-Poulenc Textiles in France began working with nonwoven <br />needled fabrics for quite different applications. Here emphasis was on reinforcement for <br />unpaved roads, beneath railroad ballast, within embankments and earth dams, and the <br />like. The primary function in many of these applications was that of separation and/or <br />reinforcement. Additionally, a quite different use of their particular style of fabric was <br />also recognized, that is, that bulky feltlike fabrics can also transmit water within the <br />plane of their structure (i.e.. they can act like drains). Such uses as dissipation of pore <br />water pressures, and horizontal and vertical flow interceptors, grew out of this particular <br />fabric function. Today ’s use of the word “geotextiles ” recognized these many possible <br />fabric functions when used within a soil mass. <br />Credit for early work in the use of geotexiiles should also be given to the Dutch <br />(the Rijkswaterstaat was an early user) and the English. ICI Fibres was a major influ ­ <br />ence in the use of nonwoven, heat-set fabrics in a wide varietv of uses. Their work and