Patent Grant
12123113
The present invention is related generally to geosynthetic fabrics. More specifically, the present invention is related to geosynthetic wicking fabrics and structures employing same.
Frost heave and thaw weakening can cause damage to various structures, including pavement structures, such as parking areas, roadways, airfields, etc., in northern regions. The formation of ice lenses in the pavement structure is a significant contributor to such damage. Three elements are necessary for ice lenses, and thus frost heave, to form. These are: (1) frost susceptible soil, (2) subfreezing temperatures, and (3) water. Often, water is available from the groundwater table, infiltration, an aquifer, or held within the voids of fine-grained soil. By removing any of the three elements above, frost heave and thaw weakening can be at least minimized or eliminated altogether.
Techniques have been developed to mitigate the damage to pavement structures caused by frost heave and thaw weakening. One such method involves removing the frost susceptible soils and replacing them with non-frost susceptible soils. The non-frost susceptible soil is placed at an adequate thickness to reduce the strain in the frost-susceptible soil layers below to an acceptable level. Other methods include use of insulation to reduce the freeze and thaw depth. In areas where removal of frost susceptible soils and reduction of subfreezing temperature are difficult and expensive, removal of water can lead to savings in construction costs by reducing the formation of ice lenses. By breaking the capillary flow path, frost action can be less severe.
A capillary barrier is a layer of coarse-grained soils or geosynthetic in a fine-grained soil that (i) reduces upward capillary flow of soil water due to suction gradient generated by evaporation or freezing, and/or (ii) reduces or prevents water from infiltrating from the overlying fine-pored unsaturated soil into the soil below the capillary barrier. In the latter case, if the capillary barrier is sloped, the infiltrating water flows in the fine soil downwards along the interface with the capillary barrier. Geosynthetic drainage nets (geonets) have been found to serve as capillary barriers because of their large pore sizes. The performance of nonwoven geotextiles as a capillary barrier appears to be compromised by soil intrusion into their interiors, decreasing the pore size and increasing the affinity of the material to water.
The above-mentioned capillary barriers attempt to cut off the capillary water flow by generating a horizontal layer with very low unsaturated permeability under suction. The whole structure is permeable for downward rainfall infiltration. This type of capillary barrier requires that the barrier thickness exceed the height of the capillary rise of water in them. In addition, it provides conditions suitable for water vapor flow because of their high porosity and comparatively low equilibrium degrees of saturation.
In another example, expansive clay soils swell and expand, more than other types of soils, with changes in moisture content, as well as shrink when they lose their moisture through seasonal and climatic changes. Expansive clay soils thus shrink more than non-expansive clay soils and thus can produce problematic cracks. For example, in a roadway, expansive clay soils tend to produce longitudinal cracks parallel to the traffic direction just at the edges of the concrete asphalt border. Thus, expansive clay soils need a material to normalize the moisture content to minimize the differential moisture movement.
The present invention is directed to a geotextile fabric including a plurality of wicking yarns each having a plurality of fibers with inter-fiber voids therebetween. The inter-fiber voids of the plurality of wicking yarns have a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1.0 milliliters per day per denier.
Another aspect of the invention is directed to a method for making a geotextile fabric including a plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween. The method includes weaving the plurality of wicking yarns in an axis of the fabric.
Yet another aspect of the invention is directed to a geotextile fabric including a plurality of texturized (or textured) fibers with inter-fiber voids therebetween. The geotextile fabric has a water flow rate of at least 2 liters/linear foot per day.
It is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Other advantages and capabilities of the invention will become apparent from the following description taken in conjunction with the accompanying drawings showing the embodiments and aspects of the present invention.
The invention will be better understood and the above objects as well as objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. Expressions such as “at least one”, “at least one kind”, “one or more kinds”, or “one or more” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. As used herein, the term “combination thereof” is used to refer to a mixture or alloy of two or more components described above.
As used herein, the term “including” is used to indicate that other components may be added or/and interposed, rather than excluding other components, unless specifically stated to the contrary. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
As used herein, the term “first”, “second”, or the like do not indicate order, quantity, or importance, and are used to distinguish one element from another. It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, unless otherwise indicated or explicitly contradicted by context, it should be interpreted as including both singular and plural. For example, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “or” means “and/or” unless otherwise specified.
Throughout the present specification, “an embodiment”, “example embodiment”, “exemplary embodiment”, etc. are included in at least one embodiment in which specific elements described in connection with the embodiment are included in this specification, which means that these elements may or may not exist in another embodiment. Further, it should be understood that the described elements may be combined in any suitable manner in various embodiments.
Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All cited patents, patent applications and other references are incorporated herein by reference in their entirety. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. However, if the terms in this specification contradict or conflict with the terms of the incorporated references, the terms from this specification take precedence over the conflicting terms in the incorporated reference.
While specific embodiments and implementations have been described, alternatives, modifications, variations, improvements and substantive equivalents that are currently unexpected or unforeseeable may occur to applicants or those skilled in the art. Accordingly, the appended claims and amendments are intended to include all such alternatives, modifications, improvements and substantial equivalents.
“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±20%, 10%, 5% of the stated value.
The terms “textured” or “texturized” are used interchangeably throughout the specification to indicate textured or texturized matter.
The present invention is directed to a geotextile fabric including a plurality of wicking yarns each having a plurality of fibers with inter-fiber voids therebetween, which optimize capillary tension in substantially a single axis to enhance moisture movement both in-plane and cross-plane around the geotextile fabric, compared to conventional fabric. The inter-fiber voids of the plurality of wicking yarns have a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1.0 milliliters per day per denier.
U.S. Pat. No. 6,152,653, describes a geocomposite capillary barrier drain (GCBD) for displacing water from beneath pavement. The GCBD system employs a transport layer, a capillary barrier, and a separator layer. Specifically, the GCBD transport layer utilizes the capillary properties of a fiberglass fabric to displace water away from the paved surface. In accordance with aspects of the present invention, the novel geotextile fabric described herein can be incorporated into a GCBD system by replacing the fiberglass fabric. Further, the novel geotextile fabric of the present invention can be employed to replace the GCBD system altogether. The novel geotextile fabric of the present invention can include a plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween. In aspects, a cross-sectional shape of each of the plurality of wicking yarns is round, oval, trilobal, multi-lobed, dumbbell, multi channeled, triangular with round edges, pillowed, or a combination thereof. In other aspects, the inter-fiber voids of the plurality of wicking yarns have a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1.0 milliliters per day per denier.
In accordance with the present invention, a geotextile fabric includes a plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween, wherein the inter fiber voids of the plurality of wicking yarns have a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1.0 milliliters per day per denier. In an embodiment, the geotextile fabric is a woven fabric, a nonwoven fabric, or a combination thereof. For example, the plurality of wicking yarns each having a plurality of fibers with inter-fiber voids therebetween can be woven into the geotextile fabric in either the warp or the weft directions. The plurality of wicking yarns has a round, an oval, a trilobal, a multi-lobed, a dumbbell, a multi channeled, a triangular with round edges, or a pillowed cross-section with a cross sectional surface area of about 1000 square centimeter per gram (cm2/g) to about 5000 square centimeter per gram. Yet, in another aspect, a fabric made from the geotextile fabric has a flow rate of about 2 liter per linear foot per day to about 20 liters per linear foot per day at zero gradient under load. Still, in another aspect, each of the plurality of wicking yarns of the geotextile fabric maintains unsaturated hydraulic conductivity in environments having a degree of saturation less than 100%. Unsaturated hydraulic conductivity refers to a measure of soil's ability to migrate water when soil pore space is not saturated with water. Different soils have different saturation points, the saturation point of a soil depends on the content, nature, and arrangement of the soil. In one or more embodiments, the plurality of wicking yarns of the geotextile remove moisture from a soil that has a saturation level less than 100%. For example, the plurality of wicking yarns of the geotextile remove moisture from a soil that has a saturation level less than about or in any range between 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, and 5%. As indicated above, the geotextile fabric of the present invention finds utility in civil and environmental engineering applications.
Wicking Yarns
In one aspect of the present invention, a plurality of wicking yarns each having a plurality of fibers (the wicking fibers) with inter-fiber voids therebetween are woven into the geotextile fabric. As a result, a fluid, such as water, is transported along the plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween, to the periphery of the geotextile fabric of the present invention. That is, the plurality of wicking yarns moves the fluid substantially along a single axis. The plurality of wicking yarns employed in the present invention has a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1.0 milliliters per day per denier. For example, in one or more embodiments, the plurality of wicking yarns employed in the present invention has a water flow of about or in any range between 0.05, 0.08, 0.10, 0.15, 0.18, 0.20, 0.22, 0.25, 0.28, 0.30, 0.33, 0.35, 0.38, 0.40, 0.43, 0.45, 0.48, 0.5, 0.55, 0,6, 0,65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, and 1.0 milliliters per day per denier. Several types of wicking yarns can be employed in the present invention and are described below.
The wicking yarns include one or more polymers or copolymers. Non-limiting examples of polymers include polyesters, nylons, polyolefins, and cellulose esters. Fibers from poly(ethylene terephthalate) and polypropylene are useful in the present invention. In some embodiments, the denier of each fiber of the plurality of wicking fibers is between about 0.5 and about 250, or between about 30 and about 170.
In embodiments, each of the plurality of wicking yarns is made of a polyamide, a polyimide, a polyethylene, a polyester, a nylon, a polyolefin, a polystyrene, a cellulose ester, a cotton, a wool, a polyetheretherketone (PEEK), and natural fiber, or a combination thereof.
In one or more embodiments, each of the plurality of textured fibers is a polyamide, a polyimide, a polyethylene, a polyester, a nylon, a polyolefin, a polystyrene, a cellulose ester, a cotton, a wool, a polyetheretherketone (PEEK), and natural fiber, or a combination thereof. In some embodiments, each of the plurality of textured fibers is a poly(ethylene terephthalate). In some other embodiments, each of the plurality of textured fibers is a polypropylene. In some other embodiments, each of the plurality of textured fibers is a nylon.
As indicated above, the plurality of wicking yarns of the present invention can be made of any polymeric material that is insoluble in the fluid which is to be contacted with the geotextile fabric. For example, the polymer utilized can be a thermo-plastic polymer, which can be extruded and drawn via an extrusion process to form the final product. Non-limiting examples of suitable polymeric materials, in addition to polyester, polystyrene and polyolefins such as polyethylene and polypropylene, include polyamides, chemical cellulose-based polymers such as viscose and di- or tri-ace-. Co-, ter-, etc. polymers and grafted polymers can also be used. Thermoplastic polymers that can be employed in the present invention are polyesters, copolymers of dicarboxylic acids, glycols, esters thereof, or any combination thereof. The dicarboxylic acid and ester compounds used in the production of polyester copolymers are well known to those of ordinary skill in the art. Such polymers include terephthalic acid, isophthalic acid, p,p′-diphenyldicarboxylic acid, p,p′-dicarboxydiphenyl ethane, p,p′-dicarboxydiphenyl hexane, p,p′-dicarboxydiphenyl ether, p,p′-dicarboxyphenoxy ethane, and the like, and the dialkylesters thereof, which contain from 1 to about 5 carbon atoms in the alkyl groups thereof.
Aliphatic glycols useful for the production of polyesters. and copolyesters are the acrylic and alicyclic aliphatic glycols having from 2 to 10 carbon atoms, such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, and decamethylene glycol.
It is additionally contemplated to utilize copolymers or graft copolymers, terpolymers, chemically modified polymers, and the like, which permanently exhibit high surface hydrophilicity and do not require the use of wetting agents, which may wash away from the structure surface upon contact with fluids. Modified polymers that can exhibit permanent hydrophilicity include chemical cellulose polymers such as cellulose acetates. In addition, pigments, delusterants, and/or optical brighteners can be included in the polymer mixtures.
A type of polyester which can be employed in the present invention is glycol modified poly(ethylene terephthalnelate) (pETG) copolyester. Suitable pETG is available from Eastman Chemical Products, Inc. (Kingsport, Tenn., USA), under the name KODAR™ 6763, with a glass transition temperature of about 81° C.
Another factor affecting polymer choice is amenability to chemical modification of its surface for increasing various properties, for example, hydrophilicity. Thus, for the geotextile fabric intended for absorbing and/or transporting aqueous based solutions, it can be advantageous to use a polyester-based polymer rather than, for example, a polypropylene. However, this selection option is not meant to thereby limit the scope of the invention. Also, depending upon the intended use of the structures, it can be desirable that the polymer material utilized be flexible at the temperatures at which the structures are intended to be used. Flexibility will depend upon such factors as the thickness and dimensions of the geotextile fabric walls and base, as well as the modulus of elasticity. Thus, choice of polymer in this regard will be highly subject to the intended use and temperature conditions. Choice of such suitable polymer material is well within the ability of one of ordinary skill in the art.
Depending upon the intended use, the geotextile fabric can be made from polymers that are either hydrophilic or oleophilic, or can be treated to be hydrophilic or oleophilic.
The surface hydrophilicity of polymers used to make the geotextile fabric of the present invention can be increased to make the inter-fiber void walls more wettable to water or aqueous solutions by treatment with surfactants or other hydrophilic compounds (hereafter, collectively referred to as “hydrophilizing agents”) known to those skilled in the art. Hydrophilizing agents include wetting agents such as polyethylene glycol monolaurates (e.g., PEGOSPERSE™ 200ML, a polyethylene glycol 200 monolaurate available from Lonza, Inc., Williamsport, Pa., USA), and ethoxylated oleyl alcohols (e.g., VOLPO™-3, available from Croda, Inc., New York, N.Y., USA). Other types of hydrophilizing agents and techniques can also be used, including those well known to those skilled in the fiber and textile arts for increasing wicking performance, improving soil release properties, etc. These include, for example, surface grafting of polyacrylic acid. Suitable commercially available hydrophilizing agents include ZELCON™ soil release agent, a nonionic hydrophile available from DuPont Co., Wilmington, Del. (USA) and Milease T™ comfort finish available from ICI Americas, Inc., Wilmington, Del., USA. In addition, ERGASURF, ceramic microbeads and vinyl pyrrolidone can be employed as hydrophilic or hygroscopic additives.
In one or more embodiments, a cross-sectional shape of each of the yarns of the plurality of wicking yarns is round, oval, trilobal, multi lobed, dumbbell, multi channeled, triangular with round edges, pillowed, or a combination thereof.
In embodiments, the geotextile fabric with the plurality of wicking yarns includes a plurality of textured wicking yarns. In one or more embodiments, the plurality of textured wicking yarns includes an air texturized wicking yarn, a wicking yarn mechanically texturized with friction or air, a staple spun texturized wicking yarn, or a combination thereof. In one or more embodiments, the plurality of textured wicking yarns includes the air texturized wicking yarn. It is understood that any suitable method resulting in inter-fiber voids can be used to texturize the plurality of wicking yarns to afford the plurality of textured wicking yarns.
In one or more embodiments, each fiber of the plurality of wicking yarns has a cross sectional surface area of about 1000 square centimeter per gram (cm2/g) to about 5000 square centimeter per gram. For example, each fiber of the plurality of wicking yarns has a cross sectional surface area of about or in any range between 1000, 1200, 1500, 1700, 2000, 2200, 2500, 2700, 3000, 3200, 3500, 3700, 4000, 4200, 4500, 4700, and 5000 square centimeter per gram. For example, each fiber of the plurality of wicking yarns has a cross sectional surface area of about 1000 square centimeter per gram to about 1500 square centimeter per gram, about 1000 square centimeter per gram to about 2000 square centimeter per gram, about 1000 square centimeter per gram to about 3000 square centimeter per gram, about 1000 square centimeter per gram to about 4000 square centimeter per gram, or about 1200 square centimeter per gram to about 2500 square centimeter per gram.
In some embodiments, each yarn of the plurality of wicking yarns each has a cross-sectional surface area of about 1500 square centimeter per gram to about 3000 square centimeter per gram. In some embodiments, each yarn of the plurality of wicking yarns has a cross-sectional surface area of about 1243 square centimeter per gram. The cross-sectional surface area of the round fiber in an embodiment is calculated as follows:
Denier=g/cm3*surface area
5 g/9000 meters*1.38 g/cm3
therefore: 5 g/900,000 cm*1.38=0.0000039 or 3.9×10−6
Surface area of a cylinder=2πrh+2πr2 where r is radius and h is height
Radius=0.0011 cm, length or height of 5 denier fiber is 180,000 cm, which provides a cross sectional surface area 1243 cm2/gram per one 5 grams per denier (gpd) fiber.
In one or more embodiments, each yarn of the plurality of wicking yarns has a hydraulic improvement factor of about 0.5 to about 2 as measured by the American Association of State Highway and Transportation Officials (AASHTO) Guide for Design of Pavement Structures 1993, and the AASHTO Mechanistic Empirical Pavement Design Guide 2015. For example, each yarn of the plurality of wicking yarns has a hydraulic improvement factor of about or in any range between 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2 as measured by the AASHTO Guide for Design of Pavement Structures 1993, and the AASHTO Mechanistic Empirical Pavement Design Guide 2015. For example, each yarn of the plurality of wicking yarns has a hydraulic improvement factor of about 0.5 to about 1.7, about 0.5 to about 1.5, about 0.5 to about 1.3, about 0.5 to about 1.1, about 0.5 to about 0.9, and about 0.5 to about 0.7 as measured by the AASHTO Guide for Design of Pavement Structures 1993, and the AASHTO Mechanistic Empirical Pavement Design Guide 2015.
In embodiments, a weight of each of the plurality of fibers is between about 0.5 denier and about 250 denier per filament. In one or more embodiments, the weight of each of the plurality of fibers is about or in any range between 10−6, 10−5, 10−4, 10−3, 0.01, 0.1, 0.5, 1.0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, and 250 denier per filament. For example, the weight is between about 10−6 denier and about 70 denier, between about 10−6 denier and about 50 denier, between about 10−6 denier and about 30 denier, between about 10−6 denier and about 10 denier, between about 10−6 denier and about 1 denier, between about 10−6 denier and about 10−4 denier, between about 10−6 denier and about 10−2 denier, between about 10−6 denier and about 10−1 denier, between about 0.5 denier and about 10 denier, between about 0.5 denier and about 15 denier, between about 0.5 denier and about 20 denier, between about 0.5 denier and about 100 denier, between about 1 denier and about 100 denier, between about 1 denier and about 20 denier, between about 1 denier and about 10 denier, and between about 1 denier and about 5 denier per filament. In some embodiments, the weight of each of the plurality of fibers is between about 0.5 denier per filament and about 100 denier per filament. In some other embodiments, the weight of each of the plurality of fibers is between about 1 denier per filament and about 5 denier per filament.
In one or more embodiments, a cross-sectional shape of each of the plurality of wicking yarns is round, oval, trilobal, multi lobed, dumbbell, multi channeled, triangular with round edges, pillowed, or a combination thereof.
In one or more embodiments, the plurality of textured fibers includes air texturized fibers, fibers mechanically texturized with friction or air, staple spun texturized fibers, or a combination thereof. In one or more embodiments, the plurality of textured fibers includes the air texturized fibers. It is understood that any suitable method resulting in inter-fiber voids can be used to make the plurality of textured fibers.
Inter-Fiber Voids
Wicking yarns employed in the present invention include a plurality of fibers with inter-fiber voids therebetween. The plurality of wicking yarns each having a plurality of fibers with inter-fiber voids therebetween of the present invention provides flexible inter-fiber void structures. The actual length of the structure is limited only by practical concerns. Although the inter-fiber void structures thereof can have one inter-fiber void or a plurality of inter-fiber voids, for convenience the plural form “voids” is used with the intent that it shall refer to a singular “void” in structures having only one such inter-fiber void or a plurality of voids in structures having more than one inter-fiber void.
The textured wicking yarns with inter-fiber voids can be created or enhanced in a non-wicking fiber using any suitable yarn bulking process such as the air-jet texturing process. For example, the air-jet texturing process is a mechanical yarn bulking process, which involves overfeeding a yarn by a supersonic air stream that develops loops and crimp. The air-jet texturizing process further entangles the fibers within the same bundle of the yarn, resulting in a uniform arrangement of synthetic continuous multi-filament yarns, each having inter fiber voids as a result of the texturizing process.
Inter-fiber voids are enhanced as a result of yarn bulking treatments, such as air-jet texturing. The inter-fiber voids can be formed in three different size scales: macro, meso, and micro. Micro-inter-fiber voids are formed between the fibers in a tow. Meso-inter-fiber voids are formed between the tows, and macro-inter-fiber voids are formed in a larger zone of the preform and are observable with the naked eye. Another term for macro-void is “dry spot.” Other terms for meso-void are “inter-bundle’,” “inter-tow,” and “channel” void. Other terms for micro-void are “intra-bundle,” “intra-tow′,” and “tow” voids.
In some embodiments, a geotextile fabric includes a plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween. The inter-fiber voids of the plurality of wicking yarns has a water flow of about 0.05 milliliters per day per denier (ml/day/denier) to about 1 milliliters per day per denier. For example, the plurality of wicking yarns has a water flow of about or in any range between 0.05, 0.08, 0.10, 0.15, 0.18, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65. 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, and 1.0 milliliters per day per denier.
In one or more embodiments, the plurality of fibers has a void ratio of about 0.8 to about 5. For example, the plurality fibers has the void ratio of about or in any range between 0.8, 1.0, 1.2, 1.4, 1.6, 1.8. 2.0. 2.2, 2.4, 2.5, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, and 5.0
In one or more embodiments, the inter-fiber voids are formed by texturizing or bulking in the fiber body resulting in the inter-fiber voids. For example, the inter-fiber voids are formed either during the manufacturing process of the fiber or yarn, or by a subsequent texturization of the manufactured yarn or fiber. Any suitable method for manufacturing or texturizing can be used to create inter-fiber voids of suitable size and void ratio.
Geotextile Fabric
In one or more embodiments, the geotextile fabric is a woven fabric, a nonwoven fabric, or a combination thereof. In some embodiments, the geotextile fabric is a nonwoven fabric. In some other embodiments, the geotextile fabric is a woven fabric.
In some embodiments, the geotextile fabric has a flow rate of about 2 liters per linear foot per day to about 20 liters per linear foot per day at zero gradient under load as measured by American Society for Testing and Materials (ASTM) 4716 method. In some other embodiments, the geotextile fabric has a flow rate of about 2 liters per linear foot per day to about 10 liters per linear foot per day at zero gradient under load as measured by American Society for Testing and Materials (ASTM) 4716 method. For example, in one or more embodiments, the geotextile fabric has a flow rate of about or in any range between 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, and 20 liters per linear foot per day at zero gradient under load as measured by American Society for Testing and Materials (ASTM) 4716 method.
In embodiments, the plurality of wicking yarns is disposed in a first axis of the geotextile fabric, and a polymeric yarn is disposed in a second axis of the fabric.
In one or more embodiments, the plurality of wicking yarns is arranged in the machine direction of the geotextile fabric, the cross machine direction, or both.
In one or more embodiments, a geotextile fabric made with the plurality of wicking yarns has a flow rate of at least 2 liters/linear foot per day. In one or more embodiments, the geotextile fabric made with the plurality of wicking yarns has a flow rate about or in any range between 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 liters/linear foot per day. For example, the geotextile fabric with the plurality of wicking yarns has a flow rate of about 2 liters/linear foot per day to about 20 liters/linear foot per day, about 2 liters/linear foot per day to about 15 liters/linear foot per day, about 2 liters/linear foot per day to about 10 liters/linear foot per day, for example, about 2 liters/linear foot per day to about 9 liters/linear foot per day, about 2 liters/linear foot per day to about 7 liters/linear foot per day, about 2 liters/linear foot per day to about 6 liters/linear foot per day, about 2 liters/linear foot per day to about 5 liters/linear foot per day, about 2 liters/linear foot per day to about 4 liters/linear foot per day, and about 2 liters/linear foot per day to about 3 liters/linear foot per day.
The plurality of wicking yarns maintains unsaturated hydraulic conductivity in saturated and unsaturated environments. In some embodiments, each of the plurality of wicking yarns maintains unsaturated hydraulic conductivity in environments having a degree of saturation of less than 100%. For example, the plurality of wicking yarns of the geotextile remove moisture from a soil that has a saturation level less than about or in any range between 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 2% and 1%.
A method for making the geotextile fabric includes weaving the plurality of wicking yarns in an axis of the fabric. The method further includes texturizing a substantially round yarn to form each of the plurality of wicking yarns, each having a plurality of fibers with inter-fiber voids therebetween. In some embodiments, a method for making the geotextile fabric includes forming a nonwoven fabric from the plurality of wicking yarns, weaving a polymeric yarn in one axis of the geotextile fabric, and weaving the plurality of wicking yarns with the polymeric yarn in another axis of the fabric, each wicking yarn of the plurality of wicking yarns having a cross-sectional shape that is substantially round and including a plurality of fibers with inter-fiber voids therebetween. In some other embodiments, the method further includes air texturizing substantially round yarns to form the plurality of wicking yarns.
In embodiments, a geotextile fabric includes a plurality of texturized (or textured) fibers with inter-fiber voids therebetween; wherein the geotextile fabric has a water flow rate of at least 2 liters/linear foot per day. In one or more embodiments, the geotextile fabric made with the plurality of texturized fibers has a flow rate about or in any range between 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 liters/linear foot per day. For example, the geotextile fabric with the plurality of texturized fibers has a flow rate of about 2 liters/linear foot per day to about 20 liters/linear foot per day, about 2 liters/linear foot per day to about 15 liters/linear foot per day, about 2 liters/linear foot per day to about 10 liters/linear foot per day, for example, about 2 liters/linear foot per day to about 9 liters/linear foot per day, about 2 liters/linear foot per day to about 7 liters/linear foot per day, about 2 liters/linear foot per day to about 6 liters/linear foot per day, about 2 liters/linear foot per day to about 5 liters/linear foot per day, about 2 liters/linear foot per day to about 4 liters/linear foot per day, and about 2 liters/linear foot per day to about 3 liters/linear foot per day.
In one or more embodiments, the plurality of texturized fibers has a void ratio of about 0.8 to about 5. For example, the plurality textured fibers have the void ratio of about or in any range between 0.8, 1.0, 1.2, 1.4, 1.6, 1.8. 2.0. 2.2, 2.4, 2.5, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, and 5.0
In one or more embodiments, the geotextile fabric is a woven fabric, a nonwoven fabric, or a combination thereof. In some embodiments, the geotextile fabric is a nonwoven fabric. In some other embodiments, the geotextile fabric is a woven fabric.
In some embodiments, a fabric made from the geotextile fabric has a flow rate of about 2 liters per linear foot per day to about 10 liters per linear foot per day at zero gradient under load as measured by American Society for Testing and Materials (ASTM) 4716 method. For example, in one or more embodiments, the fabric made from the geotextile fabric has a flow rate of about or in any range between 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10 liters per linear foot per day at zero gradient under load as measured by American Society for Testing and Materials (ASTM) 4716 method.
Weaves which can be employed in the present invention include, but are not limited to, plain, twills, specialty weaves, 3-D's, satins, sateens, honeycombs, lenos, baskets, oxfords, or panamas.
Wicking Drainage System
Referring to
In other aspects of the present invention, the wicking drainage system includes an impermeable hydrophobic geomembrane (not shown) disposed below the geotextile fabric 20. The geotextile fabric 20 allows water from the overlying soil to pass through the geotextile fabric 20 when the overlying soil is saturated and transport water laterally to side drains 70. When the overlying soil is unsaturated, the geotextile fabric can absorb water from the overlying unsaturated soil and transport it in the lateral directions. The impermeable hydrophobic geomembrane can repel water and completely cut off the capillary rise of ground water from beneath. In another aspect of the present invention, the geomembrane is a one-way-valve geotextile.
In an alternate design, the wicking drainage system includes the arrangements shown in
As illustrated in
The overall effect of the wicking drainage systems are to cut off upward capillary water flow and drain most of the infiltrated water out of the pavement structure through the tilted drainage net by the wicking geotextile fabric. The driving force for the water flow in the drainage net is gravity, and the driving forces for the water flow in the wicking fabric are gravity and suction generated by evaporation and freezing.
Table 1 shows properties of wicking yarns analyzed in the following examples.
Table 2 and
The capillary rise height is measured by Lucas-Washburn equation,
where,
As shown in
Table 3 and
Comparison of samples 5, 8, and 9 demonstrated the effect of texturization on inter-fiber voids and wicking properties of round-shaped wicking yarns. High air-texturized samples 8 and 9 showed improved wicking performance compared to the ultra-high air-texturized sample 5, again demonstrating there is an optimum range for a void ratio.
Table 4 and
Similar to Example 2, in Example 3 (Table 4 and
Table 5 and
Similar to Examples 2 and 3, in Example 4 (Table 5 and
Table 6 and
Similar to Examples 2-4, in Example 5 (Table 6 and
Examples 2-5 thus illustrate that wicking yarns with an optimum level of inter-fiber voids (either by texturization by using air-texturization, or otherwise) perform better compared to wicking yarns with an insufficient number of small voids, or large inter-fiber voids that are too far apart in distance relative to other fibers.
As shown in
Table 7 shows the flow rate test results for various fibers. The data from Table 7 shows that air texturizing increased the yarn's performance in flow rate test, especially when the yarn was initially wet, indicating the average inter-fiber void spaces or inter-fiber voids was increased (except for sample 5 with ultra-high texturizing).
Test results from Table 7 indicate that variability of test results for 4DG filaments nylon yarns. Samples 3 (entries 5-7), 4 (entries 8, 10, 17, and 28), and 10 (entries 11, 20, and 22-24) were generally higher than other yarns. Polypropylene (PP) samples 1 (entries 3, 14, and 15) and 2 (entry 31) performed the worst in both the flow rate and capillary rise tests (as shown in Table 2). It is also clear from Table 7 that increasing the number of the filaments increases the flow rate exponentially (entries 1 and 2; and 8 and 10).
Delta shaped filaments (samples 1, 2, and 6 (entry 21)) performed poorly in both capillary rise (Table 2) and flow rate test (Table 7). Table 7 also illustrates that the air texturizing is more impactful on flow rate than the type of polymer, filament count, and shape by itself. Samples 8 (entries 13, 16, 19, and 25) and 9 (entries 4, 9, and 18) showed improved performance compared to sample 7 (entries 27 and 29), and all three of samples 7, 8, and 9 include PET material, have a round shape, the same filament count, except that samples 8 and 9 are high air-texturized, whereas sample 7 is non-texturized.
Table 7 also illustrates that increasing denier per filament (dpf) decreases water transportability by increasing the inter-filament void spaces. 4DG filaments (samples 3, 4, and 10) have very small inner-fiber voids and thus perform the best in capillary rise tests (Table 2). However, the volume of water these channels move is very small when compared to the difference that results from air texturizing, as shown by samples 3, 4, and 10 from Table 7.
Table 8 and
Table 9 shows the data for void area (μm2) and void ratio for the tested wicking yarns. The prior art suggests that the higher the contact angle and the lower the polymer surface tension, the lower the wettability and water transport characteristics. However, inventors have unexpectedly discovered that creating inter-fiber voids in an optimized range improves the wettability and water transport characteristics of a yarn, thereby allowing even lower performing polymers to surpass higher performing polymers in wettability and water transport characteristics. This unexpected result lowers the cost and improves efficiency for water transport applications such as wicking drainage systems.
Table 9 shows the results for void ratio comparison for Samples 1 to 11.
In Table 10 for example, the bounding area is the assumed cross section for water transport (AT), the total number of filaments for water transport is the total number of filaments minus the number of filaments outside the bounding area, and the filament area is the individual filament area. For Sample 7, the void ratio is calculated as (263235−((192−28)×994.3)/((192−28)×994.3)=0.614. Sample 7, which is non-texturized sample, has a lower void ratio compared to air-texturized samples 8 and 9.
Assistance from Prof. Xiong Zhang, Ph.D., P. E. (Professor, Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology) and Mr. Javad Galinmoghadam, Ph.D. (Candidate, Geotechnical Engineering, Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology) are acknowledged for obtaining the experimental results for void ratio, imaging analysis and flow rate calculations.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, various modifications may be made of the invention without departing from the scope thereof and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and which are set forth in the appended claims.
This application is a U.S. nonprovisional patent application which claims priority to and the benefit of U.S. Provisional Patent Application No. 63/215,238, filed on Jun. 25, 2021, which is incorporated by reference herein in its entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 20220411974 A1 | Dec 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| 63215238 | Jun 2021 | US |
