Geotechnical composite material

Abstract

The invention relates to a geotechnical composite material which comprises two layers of geotechnical cloth and a geonet arranged between the two layers of geotechnical cloth. The geonet is made of fibers, such as glass fibers, where the fibers, such as glass fibers, have a polymer coating. The invention also relates to a method for preparing the geotechnical composite material, an asphalt pavement doped with the geotechnical composite material, and a construction method of the asphalt pavement.

Description

Technical Field

[0001] This invention relates to a geosynthetic composite material suitable for asphalt pavements, particularly for reinforcing asphalt pavements, for example, as an intermediate layer; the invention also relates to a method for preparing the geosynthetic composite material, an asphalt pavement comprising the geosynthetic composite material, and a method for using the geosynthetic composite material. Background Technology

[0002] Asphalt interlayers are commonly used in asphalt pavement construction to improve the performance of the final asphalt pavement, such as crack resistance, water permeability resistance, skid resistance, and fatigue resistance. This interlayer is laid beneath the surface layer, either directly beneath it or beneath a sub-surface layer. A wide variety of materials are used in these applications, such as basalt fiber, carbon fiber, glass fiber, or geotextile. Some interlayers contain exposed fibers, such as glass fiber. These fibers possess the material properties required to improve asphalt pavement, but they are prone to breakage during unwinding. To improve workability, the fibers are typically secured to the geotextile layer, such as through stitching, or otherwise embedded within the geotextile layer, thereby protecting the fibers during unwinding.

[0003] Existing interlayers are prone to wrinkles and ridges during installation. To reduce the formation of these raised areas, the installation speed must be slowed down. After the initial installation, deformation must be visually inspected and manually eliminated by sweeping, tamping, or slitting. Without this operation, these raised areas will adversely affect the performance of the final asphalt pavement. If corrected by slitting, the resulting gaps will become structural weak points within the asphalt pavement. Therefore, although the advantages of adding interlayers to asphalt pavements are obvious, the process of effectively installing interlayers to realize these advantages is time-consuming and labor-intensive. Furthermore, there is a desire to further improve the tensile strength of the interlayer.

[0004] The purpose of this invention is to solve one or more of the problems mentioned above. Summary of the Invention

[0005] A first aspect of the present invention provides a geosynthetic composite material comprising two layers of geotextile and a geonet disposed between the two layers of geotextile, the geonet being made of fibers, such as glass fibers, wherein the fibers, such as glass fibers, have a polymeric coating.

[0006] Geonets can be made of woven fibers, knitted fibers, or nonwoven loose fibers, such as woven glass fiber, knitted glass fiber, or nonwoven loose glass fiber. Geonets can have generally quadrilateral apertures, such as generally rectangular or square apertures. The size of the quadrilateral apertures can be 5–50 mm, preferably 6–25 mm, and more preferably 6–12.5 mm.

[0007] Polymer coatings may include polyacrylates.

[0008] The tensile strength of geonet can be 25~400KN / m, preferably 25~200KN / m, more preferably 50~150KN / m, such as about 100KN / m.

[0009] Geotextiles can be non-woven fabrics; their materials may include polyesters, such as polyethylene terephthalate (PET) and PET blends, or polyolefins, such as polypropylene (PP) or PP blends. The basis weight of the geotextile can be 10~200 g / m², preferably 15~140 g / m², more preferably 15~40 g / m². The geotextile may be uncoated, such as with a polymer coating.

[0010] Geonets can be fixed to one or more layers of geotextile, such as by stitching, adhesive bonding, or lamination.

[0011] A second aspect of the present invention provides a method for preparing a geotextile composite material, the method comprising: disposing a geonet comprising fibers, such as glass fibers, between two layers of geotextile, the fibers, such as glass fibers, having a polymer coating; and fixing a first layer of geotextile to one or both of the second layer of geotextile and the geonet.

[0012] Geonets can be made from woven or knitted fibers, such as glass fibers, or by making fibers, such as glass fibers, into a nonwoven loose fabric.

[0013] The method may also include the step of coating fibers, such as glass fibers, with a polymer coating, preferably by spray coating.

[0014] Fixation can be achieved by using adhesives, preferably by bonding between the first layer of geotextile, the geonet and the second layer of geotextile.

[0015] The geosynthetic composite material prepared by the method of the second aspect of the present invention can be the geosynthetic composite material as described in the first aspect of the present invention.

[0016] A third aspect of the present invention provides an asphalt pavement comprising: a substrate; an asphalt course comprising aggregate and binder; and a geosynthetic composite material, as described in the first aspect of the present invention, disposed between the substrate and the asphalt course.

[0017] Geocomposite materials can be virtually free of raised areas and / or slits.

[0018] The asphalt pavement may also include a tack coat disposed between the base and the geosynthetic composite material. The base may be an asphalt mixture. The thickness of the asphalt mixture layer may be 30 to 300 mm. The binder may be bitumen. The average particle size of the aggregate may be 5 to 35 mm. A fourth aspect of the present invention provides a method for constructing an asphalt pavement, the method comprising: laying a geosynthetic composite material as described in the first aspect of the present invention on a substrate; laying a layer of asphalt mixture on the laid geosynthetic composite material, the asphalt mixture comprising a binder and aggregates; compacting the asphalt mixture; and allowing the binder to solidify.

[0019] The laid geosynthetic materials can be virtually free of raised areas and / or narrow gaps.

[0020] The substrate can be an asphalt mixture. The method may also include the step of applying a bonding layer, which may be asphalt, to the substrate before laying the geosynthetic composite material. The thickness of the asphalt mixture layer can be 30–300 mm. The binder can be asphalt. The average particle size of the aggregate can be 5–35 mm. Attached Figure Description

[0021] Figure 1A and Figure 1B The top and bottom surfaces of the geocomposite material (100) of the present invention are shown. The geocomposite material (100) includes a geonet (110) made of glass fiber and having a polymer coating, which is disposed between two geotextiles (120). The two geotextiles (120) are white and translucent, so that the geonet (110) can be observed as a black geonet.

[0022] Figure 2 A cross-sectional schematic diagram of the geocomposite material (100) of the present invention is shown. The geocomposite material (100) includes a geonet (110) made of fibers, such as glass fibers, and having a polymer coating, which is disposed between two geotextiles (120).

[0023] Figure 3A schematic cross-sectional view of a beam used for four-point bending beam testing is shown. The asphalt mixture beam on the left side incorporates the geosynthetic composite material of this invention, while the asphalt mixture beam on the right side lacks an intermediate layer.

[0024] Figure 4 A cross-sectional schematic diagram of the four-point bending beam test apparatus is shown.

[0025] Figure 5 The graph shows the extrapolated increase in fatigue life between the comparative interlayer specimen and the inventive geocomposite specimen compared to the control group. As can be seen from the graph, the performance of the inventive geocomposite is superior to that of the interlayer using glass fiber with the same ultimate tensile strength. Detailed Implementation

[0026] A first aspect of the present invention provides a geocomposite material comprising two layers of geotextile and a geonet disposed between the two layers of geotextile. The geonet is made of fibers, such as glass fibers, wherein the fibers, such as glass fibers, have a polymer coating. The geonet disposed between the two layers of geotextile can, to a certain extent, protect the geonet from damage caused by external forces during the installation of the geocomposite material, thus preventing damage to the fibers constituting the geonet, such as glass fibers; the presence of the polymer coating further enhances this protective effect. This material structure enables the geocomposite material to possess both good workability and sufficient tensile strength, achieving high performance when used as an asphalt interlayer, while also avoiding the problem of raised areas, such as wrinkles, during installation. While not wishing to be bound by theory, the inventors believe that the geocomposite material exhibits improved stiffness within the plane formed by the geotextiles, thereby reducing or even eliminating the generation of out-of-plane areas (i.e., raised areas). In some embodiments, when the geocomposite material is laid over a 75-meter span on a milled asphalt surface, the observed probability of wrinkles is less than 80 per 304 meters (1000 feet), preferably less than 50 per 304 meters (1000 feet), more preferably less than 30 per 304 meters (1000 feet), further preferably less than 10 per 304 meters (1000 feet), and most preferably about 0 per 304 meters (1000 feet).

[0027] Geonets are made of fibers. The fibers are high-stiffness fibers, and suitable fibers can be selected from glass fibers, basalt fibers, carbon fibers, and combinations thereof. In a preferred embodiment, the geonet is made of glass fibers. This can mean that the geonet is composed of fibers, such as glass fibers, along with other components that allow the fibers to maintain the geonet structure, or that the geonet is composed of fibers, such as glass fibers, or is primarily composed of fibers, such as glass fibers. In some embodiments, the fibers are in the form of woven fibers, knitted fibers, or nonwoven loose fabric. In specific embodiments, the glass fibers are in the form of woven glass fibers, knitted glass fibers, or nonwoven loose fabric glass fibers.

[0028] In this document, "geonet" or "geonet structure" refers to a planar mesh structure formed by arranging fibers, such as glass fibers, with regular and repeating openings between the strands or bundles of fibers, such as glass fibers. The openings can be of almost any shape. Because the openings allow aggregate to enter completely or partially, they enhance the interaction between the aggregate (and the bitumen containing that aggregate) and the geocomposite material. Preferably, the openings are generally quadrilateral, as such structures are easier to manufacture and possess tensile strength in both the machine direction and the cross direction. Quadrilateral openings can be generally rectangular or generally square. Quadrilateral openings can have any suitable size, such as 5–50 mm, preferably 6–25 mm, more preferably 6–12.5 mm.

[0029] The fiber, such as glass fiber, has a polymer coating, preferably a polyacrylate coating, and any suitable polyacrylate can be used. Preferably, the polymer coating substantially covers the entire surface of the fiber, such as glass fiber. The weight ratio of the fiber, such as glass fiber, to the polymer coating can be 10:1 to 3:1, preferably 8:1 to 3.5:1, and more preferably 6:1 to 4:1.

[0030] The coating restricts the relative mobility of fibers, such as glass fibers, ensuring the geonet maintains its structural shape. The coating also increases the stiffness of the geonet, and higher stiffness enhances the planarity of the geocomposite, making it easier to lay flat and preventing wrinkles. Furthermore, the coating can alter the surface properties of fibers, such as glass fibers, improving their interaction with asphalt in the asphalt mixture and increasing the geocomposite's moisture resistance. In a preferred embodiment, each individual fiber is coated (i.e., the fibers have a polymer coating before forming the geonet). This approach provides the fibers with the protective effect of the polymer coating while preventing an undesirable increase in the stiffness of the final geonet, allowing the geocomposite to adapt to unevenness in the underlying substrate to some extent.

[0031] Geonets need to possess sufficient tensile strength to reinforce asphalt pavements. For example, the tensile strength of the geonet can be 25~400 kN / m, preferably 25~200 kN / m, more preferably 50~120 kN / m, such as approximately 100 kN / m. Tensile strength can be determined according to the specifications of ASTM D 6637M-15 (2023).

[0032] Geotextiles can be made of any suitable material. It should be understood that the geotextiles used herein differ from geonets in that they do not have openings that allow aggregates or other solids to enter completely. Preferably, the geotextile is a non-woven fabric because such materials have advantageous porosity, allowing for more complete absorption of the binder material in the asphalt mixture (and, if a bonding layer is used, also the bonding layer material), and a stronger interaction with it. This more complete absorption and adsorption improves the interaction between the geotextile and the asphalt pavement and enhances the performance of the geocomposite as a moisture barrier. Geotextiles may contain polyesters, such as polyethylene terephthalate (PET) and PET blends, or polyolefins, such as polypropylene (PP) or PP blends, which can strongly interact with the binder material in the asphalt mixture. Geotextiles preferably contain PET.

[0033] The basis weight of the geotextile can be 10~200g / m², preferably 15~140g / m², and more preferably 15~40g / m².

[0034] Preferably, the geotextile is white. The white color of the geotextile increases the cooling rate of the geocomposite surface, thereby shortening the time required for the geocomposite to fully adhere to the surface for asphalt pavement laying. It should be understood that the geonet separates the two layers of geotextile, allowing the upper geotextile (i.e., the layer not in contact with the underlying surface) to remain white during use, while the lower geotextile still maintains good contact with the underlying surface and the bonding layer coated on that surface (the bonding layer can cause the geotextile to fade). While not wishing to be bound by theory, the inventors believe that white color increases the heat dissipation rate of the geocomposite and reduces solar gain. In some embodiments, the temperature reduction is 5% to 10% compared to a black interlayer in the prior art.

[0035] This structural design of geotextile layers and geonets brings several additional advantages to geosynthetics. Geosynthetics are highly durable yet can still be easily cut with hand tools, such as scissors, allowing them to be cut around obstacles, such as ferrous components (e.g., manhole covers and gratings). Geosynthetics combine durability and chemical stability, ensuring their effectiveness throughout the service life of asphalt pavements. Furthermore, geosynthetics possess excellent milling properties, enabling asphalt pavements to be recycled through milling at the end of their service life.

[0036] Geonets can be fixed to one or more layers of geotextile. This fixing process ensures the geocomposite material maintains its structural stability during transport and installation. Geonets can be fixed by any suitable method, such as sewing, adhesive bonding, or lamination. Alternatively, the geotextile layers can be fixed to each other. In embodiments where the geonet is not fixed to any geotextile layer, the presence of the geonet prevents direct contact between the two geotextile layers, creating a pocket-like space in that area. This pocket-like space allows for the positioning of the geonet through mutual fixation of the geotextile layers. In embodiments where the geonet is fixed to any geotextile layer, this mutual fixation further ensures the geocomposite material maintains its intended structural morphology. Two geotextile layers can be fixed to each other by any suitable method, such as sewing, adhesive bonding, or thermal processing methods, such as thermolamination or ultrasonic welding. In a preferred embodiment, the two geotextile layers are bonded to the geonet. It should be understood that a polymer coating on the fibers, such as glass fiber, can advantageously improve adhesion strength. Geotextiles used in such applications are typically coated, whether intentionally applied or as a byproduct of fixing the geonet. Preferably, the geotextile is substantially free of polymer coatings, such as adhesive coatings or polymer coatings. Without being theoretically limited, it is believed that coatings on geotextiles increase their stiffness and reduce their ability to interact with bitumen (and, if present, with the bonding layer), thereby leading to poorer layability.

[0037] The width of the geosynthetic composite material can be adjusted arbitrarily according to the design width of the asphalt pavement. The width of the geosynthetic composite material can be 1 to 5 meters, preferably 1.5 to 4.5 meters; in the exemplary embodiment, the width of the geosynthetic composite material can be set to 1.5 meters, 3 meters or 3.8 meters.

[0038] Geocomposites are preferably supplied in roll form for ease of transport. In use, the geocomposites are unrolled from the roll and then laid onto the substrate where the asphalt layer will be formed.

[0039] A second aspect of the present invention provides a method for preparing a geotextile composite material, the method comprising: disposing a geonet comprising fibers, such as glass fibers, between two layers of geotextile, wherein the fibers, such as glass fibers, have a polymer coating; and fixing a first layer of geotextile to one or both of the other layer of geotextile and the geonet. The resulting geotextile composite material is the same as the geotextile composite material of the first aspect of the present invention.

[0040] Geonets can be prepared by arranging fibers, such as glass fibers, into a suitable structure in any suitable manner. Preferably, the geonet is prepared by weaving or knitting fibers, such as glass fibers, into a geonet structure, or by forming fibers, such as glass fibers, into a nonwoven fabric. Compared to other fiber laying methods, geonet structures prepared in the above methods are more stable and have higher stiffness. For example, fibers, such as glass fibers, that are only laid, for example, in the longitudinal and transverse directions, without being fixed by weaving, knitting, or nonwoven fabric processes, are more likely to move relative to each other, resulting in a geonet with lower strength and poorer uniformity of pore size.

[0041] This method may include a coating step on fibers, such as glass fibers. In some embodiments, the coating step is performed before the fibers, such as glass fibers, form the geonet. Preferably, the coating step is performed after the fibers, such as glass fibers, form the geonet. The fibers, such as glass fibers, can be coated by any suitable process, such as by dip coating, brushing, or spraying a coating material solution. The applied coating material can be air-dried or dried more quickly by heating and / or forced ventilation. For example, the applied coating material can be dried by infrared heating.

[0042] The first layer of geotextile is fixed to one or two layers of geotextile or geonet, which can be achieved by any suitable method, such as sewing, using adhesives, or using heating methods, such as hot lamination or ultrasonic welding. Ensuring a strong adhesion between the geotextile and geonet prevents interlayer separation of the geocomposite material during installation. Preferably, adhesives are used for fixing. In a preferred embodiment, the first layer of geotextile, the geonet, and the second layer of geotextile are bonded together using an adhesive. In a specific embodiment, adhesive is applied to each surface of the geonet, and each layer of geotextile is pressed onto the surface. Heating can accelerate the curing of the adhesive.

[0043] Between each manufacturing step, intermediate products (such as geonets made of fibers, like glass fibers, or geonets made of coated fibers, like coated glass fibers) can be wound into rolls and stored. Alternatively, the steps of this method can be performed continuously. In one example, the geonet is first made, then the fibers, such as glass fibers, are coated, and subsequently the geonet made of the coated fibers, such as coated glass fibers, is wound into rolls. In another example, the geonet is first made, then the fibers, such as glass fibers, are coated, then the geotextile is fixed, and finally the finished geocomposite material is packaged into rolls and stored.

[0044] A third aspect of the invention relates to an asphalt pavement comprising a base, an asphalt mixture layer containing aggregates and a binder, and a geosynthetic composite material as described in the first aspect of the invention disposed between the base and the asphalt mixture layer.

[0045] Geocomposite materials can be substantially free of raised areas and / or gaps. In some embodiments, when the geocomposite material is laid over a milled asphalt surface over a span of 75 meters, the number of observed wrinkles is less than 80 per 304 meters (1000 feet), preferably less than 50 per 304 meters (1000 feet), more preferably less than 30 per 304 meters (1000 feet), further preferably less than 10 per 304 meters (1000 feet), and most preferably about 0 per 304 meters (1000 feet). The presence of raised areas, and the gaps created when correcting such areas, can lead to a decline in the performance of asphalt pavements.

[0046] Asphalt pavements may also include a bonding layer. This bonding layer, placed between the substrate and the geocomposite material, enhances the contact and adhesion between the two. This helps the geocomposite material achieve a smooth, bonded surface and withstand vehicle traffic before the asphalt mixture is deposited. The bonding layer also improves the shear strength of the substrate-geocomposite interface. The bonding layer can be made of asphalt or asphalt emulsion. Typically, asphalt emulsions use asphalt as a binder, but polymer-modified asphalt can also be used.

[0047] The substrate can be any substantially flat surface. Preferably, the substrate is concrete or asphalt mixture. The asphalt mixture can be newly laid asphalt mixture, existing asphalt mixture, or milled asphalt mixture. Preferably, the substrate is kept clean and dry before installing the geosynthetic composite material.

[0048] It is understood that the asphalt mixture layer mentioned in this article refers to the asphalt mixture layer laid on top of the geosynthetic composite material. The thickness of the asphalt mixture layer can be selected according to the expected use scenario. The thickness of the asphalt mixture layer can be 300mm to 30mm; the greater the load, the thicker the asphalt mixture layer needs to be. The preferred aggregate layer thickness is 250mm to 30mm, more preferably 200mm to 30mm, further preferably 150mm to 30mm, and most preferably 100mm to 37.5mm.

[0049] The asphalt mixture layer can use any suitable binder. Typically, the binder is asphalt, which can be hot-applied or cold-applied asphalt.

[0050] The aggregate can be any suitable particulate matter. The aggregate particle size is typically 5 mm to 35 mm, preferably 10 mm to 32 mm. The aggregate particle size can also be a maximum of 11 mm, 16 mm, 22 mm, or 32 mm. The aggregate particle size can be determined by sieving, such as according to BS EN 933-1:2012.

[0051] The asphalt mixture layer may also include recycled asphalt mixture, additional binders or fillers.

[0052] The fourth aspect of the present invention relates to a method for constructing an asphalt pavement, the method comprising: installing a geosynthetic composite material of the first aspect of the present invention on a substrate; laying an asphalt mixture layer on top of the installed geosynthetic composite material, the asphalt mixture layer comprising aggregates and a binder; compacting the asphalt and allowing the binder to solidify.

[0053] When laying geosynthetic materials, the rolls can be pushed forward along the substrate and unrolled, with the unrolling speed matching the pushing speed. This ensures that the unrolled geosynthetic material maintains a certain tension, preventing wrinkles. In some embodiments, at the point where the unrolled geosynthetic material contacts the substrate, a roller or brush is used to press the geosynthetic material onto the substrate. Preferably, a suitable mechanical method, such as a tractor, is used to carry out the installation work, ensuring that the geosynthetic material is laid with stable tension and uniform distribution when it reaches the substrate (or, if an adhesive layer exists).

[0054] Preferably, the installed geosynthetic material is substantially free of protruding areas and / or slits. In some embodiments, when the geosynthetic material is laid over a milled asphalt surface with a span of 75 meters, the number of observed wrinkles is less than 80 per 304 meters (1000 feet), preferably less than 50 per 304 meters (1000 feet), more preferably less than 30 per 304 meters (1000 feet), further preferably less than 10 per 304 meters (1000 feet), and most preferably about 0 per 304 meters (1000 feet). The installed geosynthetic material is substantially free of the aforementioned defects. While not wishing to be bound by theory, the inventors believe that higher in-plane stiffness can reduce or even eliminate the generation of protruding areas, thereby reducing or even eliminating the need for slits to address such protruding areas.

[0055] The substrate can be any substantially flat surface. Preferably, the substrate is concrete or asphalt mixture. The asphalt mixture can be newly laid asphalt mixture, existing asphalt mixture, or milled asphalt mixture. Preferably, the substrate is kept clean and dry before installing the geosynthetic composite material.

[0056] The thickness of the asphalt mixture layer can be 300mm to 30mm. The greater the load, the thicker the asphalt mixture layer needs to be. Preferably, the thickness of the aggregate layer is 250mm to 30mm, more preferably 200mm to 30mm, even more preferably 150mm to 30mm, and most preferably 100mm to 37.5mm.

[0057] Any suitable binder can be used for the asphalt mixture layer. Typically, the binder is asphalt, which can be hot-applied or cold-applied asphalt.

[0058] The aggregate can be any suitable particulate matter. The aggregate particle size is typically 5–35 mm, preferably 10–32 mm. Aggregate particle sizes can also be as high as 11 mm, 16 mm, 22 mm, or 32 mm. The aggregate particle size can be determined by sieving, such as according to BS EN 933-1:2012.

[0059] The asphalt mixture layer may also include recycled asphalt mixture, additional binders or fillers.

[0060] This method may also include the step of applying a bonding layer to the substrate before installing the geocomposite material. The bonding layer also improves the shear strength at the interface between the substrate and the geocomposite material. The bonding coating can be made of bitumen or bitumen emulsion. Typically, bitumen emulsions use bitumen as a binder, but polymer-modified bitumen can also be used.

[0061] This method allows for a cooling period to bring the bonding layer down to a suitable temperature for asphalt paving. If the temperature is too high, the viscosity and adhesion of the bonding layer are insufficient to prevent geotextile displacement. Preferably, the geotextile is white. It is understood that separating the two geotextile layers with a geonet allows the upper geotextile (i.e., the layer not in contact with the underlying surface) to remain white during use, while the lower geotextile can still maintain good contact with the underlying surface and any bonding layers applied thereon (which can cause fading). Without being theoretically limited, the inventors believe that white can accelerate the thermal radiation rate of geocomposite materials and reduce solar radiation absorption. In some embodiments, the cooling effect is 5% to 10% compared to the black interlayer in the prior art.

[0062] The asphalt mixture layer must be compacted before the binder sets. In some cases, compaction may not be necessary. Compaction can be achieved by any suitable method, such as using vibration and / or applying pressure.

[0063] The setting of the binder refers to the process by which the binder solidifies and forms a matrix, in which the aggregate is fixed, thereby solidifying the asphalt mixture layer. Depending on the properties of the binder, setting can be achieved through binder cooling (i.e., solidification), solvent evaporation in the binder, or a combination of both. Example

[0064] Cover test The exemplary geosynthetic composite material of the present invention was applied to a test asphalt pavement, and overlay tests were conducted according to Tex-248-F (2013). The asphalt pavement mixture consisted of granite material with a nominal maximum aggregate size (NMAS) of 12.5 mm, asphalt binder (based on PG 76-22), and 20% recycled asphalt pavement material (RAP), with a porosity of 7%. First, a 50.8 mm thick asphalt mixture layer was compacted and cooled, followed by the application of a binder layer (PG 67-22) and the laying of the geosynthetic composite material. After the geosynthetic composite material was fixed, a second 50.8 mm thick asphalt mixture layer was laid and compacted on top. The initial thickness of the prepared specimen was 101.6 mm, which was reduced to 62.5 mm before the test, with the geosynthetic composite material having a thickness of 25 mm at the bottom and 37.5 mm at the top. A 12.5 mm notch was cut at the bottom of the specimen to simulate a crack in the lower layer, and the specimen was painted white to facilitate observation of crack propagation.

[0065] In this overlay test method, the specimen was first stretched by 0.6 mm and then restored to its original length. This cycle was completed within 10 seconds and repeated until the specimen failed. For example, failure was defined as when the specimen lost 93% of its peak strength, or after 1000 cycles. The failure cycle number was recorded. The crack propagation rate was also measured, which characterizes the degree of decrease in the load required for crack propagation. A lower crack propagation rate indicates better resilience of the specimen. The same overlay test was conducted on control specimens without an intermediate layer. Due to the small specimen size and the significant difference in modulus between glass fiber and asphalt, the test was conducted at 0°C.

[0066] The control group specimens without an intermediate layer failed relatively quickly and exhibited a high crack propagation rate (CPR). The performance of intermediate layers in existing technologies is inconsistent, showing only a limited improvement compared to the control group. Conversely, specimens incorporating geosynthetic composites did not fail even after 1000 cycles and showed a low CPR, confirming the strength and resilience improvements brought about by geosynthetic composites.

[0067] Four-point bending beam test A four-point bending beam test apparatus was used to determine the energy required for crack initiation and crack propagation in an asphalt mixture beam at a temperature of approximately 20°C. The asphalt mixture beam had the following structure: a 30mm thick base course using AC 11 W 35 / 50 asphalt mixture (composed of granite with a maximum aggregate size of 11.2mm and 4.8wt% 35 / 50 asphalt); and a 70mm thick surface course using AC 16 W 35 / 50 asphalt mixture (composed of granodiorite with a maximum aggregate size of 16.0mm and 4.8wt% 35 / 50 asphalt); geosynthetic composite materials were placed between the base course and the surface course. The total height (H) of the asphalt mixture beam was 100mm, and its length (L) was 850mm.

[0068] Figure 3 This is a schematic diagram of the test apparatus. Static contact points are set below the asphalt mixture beam with a spacing of 740 mm (B); dynamic contact points are set above the beam with a spacing of 247 mm (A). The asphalt mixture beam to be tested is loaded into the test apparatus, ensuring that the distance between the center of the beam and each static contact point and each dynamic contact point is equal.

[0069] A static load was applied to achieve a displacement rate of 50 mm per minute, while the crack initiation energy and crack propagation energy were recorded. This experiment tested two asphalt-mixed beams incorporating exemplary geosynthetic materials, with a control beam without an intermediate layer and an asphalt-mixed beam incorporating a prior art intermediate layer serving as references.

[0070]

[0071] After incorporating the exemplary geosynthetic composite material, the crack initiation energy was increased by 55% and 114% compared to the control group without an intermediate layer, and by 27% and 75% compared to the prior art intermediate layer samples, respectively. This means that the exemplary geosynthetic composite material can significantly delay the cracking time of asphalt pavement. In addition, after incorporating the geosynthetic composite material, the crack propagation energy was nearly doubled (increased by 97% and 108% compared to the control group without an intermediate layer, and by 54% and 63% compared to the prior art intermediate layer samples, respectively). This indicates that once a crack occurs, its propagation rate in asphalt is slowed down due to the presence of the geosynthetic composite material.

[0072] Laying performance The test section of the asphalt pavement was milled, and surface debris was removed. The asphalt binder (PG 64-10) was heated and applied at 0.18 gallons per square yard (0.81 L m²). -2 The amount of the inventive geosynthetic composite material 2 is applied to the road surface to form a bonding layer. The inventive geosynthetic composite material 2 and the comparative intermediate layer 2 are laid side by side to directly compare their paving performance.

[0073] Compared to the comparative intermediate layer 2, the geotextile composite material 2 of the present invention is quicker and easier to unwind and lay, resulting in a smoother surface with fewer wrinkles and ridges, eliminating the need for extensive manual cutting and / or leveling. The geotextile composite material 2 of the present invention maintains a smooth surface after laying and achieves good adhesion to the bonding layer. Furthermore, during the subsequent asphalt mixture deposition process, no material damage or delamination was observed when construction vehicles drove on the geotextile composite material 2. Subsequently, using conventional techniques, asphalt mixture layers were laid on top of both the geotextile composite material 2 of the present invention and the comparative intermediate layer 2. The bonding effect between the geotextile composite material 2 of the present invention and the asphalt mixture layer was excellent, ultimately resulting in a pavement with excellent smoothness.

[0074] Researchers also conducted comparative tests on geotextile composite material 1 and geotextile composite material 2 of the present invention, and polypropylene geotextile. The test results again showed that the geotextile required a slow laying speed and extensive repair work to eliminate raised areas; while geotextile composite material 1 and geotextile composite material 2 of the present invention were easy to lay and could quickly form a smooth surface suitable for laying asphalt mixture layers. Furthermore, severe adhesive layer penetration occurred on the surface of the geotextile, hindering the subsequent deposition of asphalt mixture layers.

[0075] In summary, the experimental results demonstrate that the exemplary geocomposite material exhibits superior layability compared to existing intermediate layers (including fiberglass and polypropylene geotextile intermediate layers). Using this material allows for simpler and more efficient construction of high-quality surface layers. While not wishing to be bound by theory, researchers believe that the improved layability, such as the reduced probability of wrinkles and ridges, is attributed to improved material-binder interaction, while the coating on the geotextile and fiberglass surfaces also enhances the overall stiffness of the material.

[0076] fatigue test A four-point bending beam test apparatus was used to determine the fatigue life of asphalt mixture beams fabricated according to the four-point bending beam test method described above. The test was conducted in a controlled strain mode at a temperature of approximately 20°C and a frequency of 5 Hz. Repeated strains of 300, 240, 400, 450, and 500 µε were applied to the asphalt mixture beams until the specimens failed (i.e., a 50% strength loss). The failure cycle number under each strain condition was recorded and plotted. The fatigue life at 70, 100, and 130 µε was calculated using extrapolation, and the improvement in fatigue life compared to the control specimen without geosynthetic composite material was then calculated. These lower strain values ​​are closer to actual engineering conditions, but due to time constraints, this data could not be obtained through experimental measurement.

[0077]

[0078] The relevant data was also plotted in Figure 5 Data shows that incorporating the invented geosynthetic composite material increased the fatigue life of asphalt mixture beams by 10 to 31 times. It also exhibited a significant performance improvement compared to a comparative intermediate layer using glass fiber with the same ultimate tensile strength.

[0079] Time Saving Calculation The geosynthetic composite material of this invention and a comparative intermediate layer were laid side by side over a span of 23 meters (75 feet), and the number of wrinkles requiring correction for each material was counted. The results showed that the geosynthetic composite material of this invention did not exhibit any wrinkles requiring correction; in contrast, the comparative intermediate layer showed 80 to 133 wrinkles requiring correction per 304 meters (1000 feet).

[0080] Based on the standard calculation that repairing a single wrinkle requires 1 to 5 minutes of labor, compared to a comparative intermediate layer, using the geosynthetic composite material of this invention can save 80 to 665 minutes of labor per 304 meters (1000 feet) of asphalt pavement. At a shift labor rate of $5.33 per minute, this translates to a saving of $426 to $3544 in labor costs per 304 meters (1000 feet) of asphalt pavement. In addition to direct time savings, this advantage also shortens the overall construction cycle of asphalt pavement and reduces road downtime.

[0081] Both the geosynthetic composite material of this invention and the comparative intermediate layer are laid on top of a hot-melt bonding layer. Before laying asphalt, the bonding layer must be allowed to cool to a suitable asphalt laying temperature; otherwise, its viscosity and adhesion will be too low, causing displacement of both the geosynthetic composite material of this invention and the comparative intermediate layer during asphalt mixture deposition and construction vehicle traffic. Experimental observations revealed that, in addition to a reduced probability of wrinkling, the bonding layer of the geosynthetic composite material of this invention cools to a suitable asphalt laying temperature much faster than the comparative intermediate layer. Calculations show that the cooling time can be shortened by 5% to 10%.

Claims

1. A geosynthetic composite material, characterized in that, It includes two layers of geotextile and a geonet disposed between the two layers of geotextile, the geonet being made of fibers, such as glass fibers, wherein the fibers, such as glass fibers, have a polymer coating.

2. The geosynthetic composite material according to claim 1, characterized in that, The geonet is made of woven fibers, knitted fibers, or nonwoven loose fibers, such as woven glass fiber, knitted glass fiber, or nonwoven loose glass fiber.

3. The geosynthetic composite material according to claim 1 or 2, characterized in that, The geonet has approximately quadrilateral openings, such as approximately rectangular or square openings.

4. The geosynthetic composite material according to claim 3, characterized in that, The size of the quadrilateral opening is 5~50mm, preferably 6~25mm, and more preferably 6~12.5mm.

5. The geosynthetic composite material according to any one of the preceding claims, characterized in that, The polymer coating comprises polyacrylate.

6. The geosynthetic composite material according to any one of the preceding claims, characterized in that, The tensile strength of the geonet is 25~400KN / m, preferably 25~200KN / m, more preferably 50~150KN / m, such as about 100KN / m.

7. The geosynthetic composite material according to any one of the preceding claims, characterized in that, The geotextile: (i) is a nonwoven fabric; and / or (ii) Contains polyesters, such as polyethylene terephthalate (PET) and PET blends, or polyolefins, such as polypropylene (PP) and PP blends; and / or (iii) The basis weight is 10~200 g / m², preferably 15~140 g / m², more preferably 15~40 g / m²; and / or (iv) Essentially uncoated, such as with polymer coatings.

8. The geosynthetic composite material according to any one of the preceding claims, characterized in that, The geonet is fixed to one or more layers of geotextile by stitching, adhesive bonding or lamination.

9. A method for preparing geosynthetic composite materials, characterized in that, The method includes: A geonet comprising fibers, such as glass fibers, is disposed between two layers of geotextile, wherein the fibers, such as glass fibers, have a polymer coating; and The first layer of geotextile is fixed to one or both of the second layer of geotextile and the geonet.

10. The method according to claim 9, characterized in that, The geonet is made from woven or knitted fibers, such as glass fiber, or by making the fibers, such as glass fiber, into a nonwoven loose fabric.

11. The method according to claim 9 or 10, characterized in that, It also includes the step of coating the fiber, such as glass fiber, with the polymer coating, preferably by spray coating.

12. The method according to any one of claims 9 to 11, characterized in that, Fixation is achieved by using an adhesive, preferably by fixing the first layer of geotextile, the geonet, and the second layer of geotextile together through adhesive force.

13. The method according to any one of claims 9 to 12, characterized in that, The geosynthetic composite material is any one of claims 1 to 8.

14. An asphalt pavement, characterized in that, include: Base; Asphalt mixture layer containing aggregates and binders; as well as The geosynthetic composite material according to any one of claims 1 to 8 is disposed between the substrate and the asphalt mixture layer.

15. The asphalt pavement according to claim 14, characterized in that, The surface of the geosynthetic material is basically free of protruding areas and / or slits.

16. The asphalt pavement according to claim 14 or 15, characterized in that: (i) The asphalt pavement further includes an adhesive layer disposed between the substrate and the geosynthetic composite material; and / or (ii) The substrate is an asphalt mixture; and / or (iii) The thickness of the asphalt mixture layer is 30~300mm; and / or (iv) The adhesive is bitumen; and / or (v) The average particle size of the aggregate is 5~35mm.

17. A construction method for asphalt pavement, characterized in that, The method includes: The geosynthetic composite material of any one of claims 1 to 8 is laid on the substrate; An asphalt mixture layer is laid on the already laid geosynthetic composite material, the asphalt mixture comprising a binder and aggregates; Compacting the asphalt mixture; and The adhesive is then allowed to solidify.

18. The method according to claim 17, characterized in that, The surface of the laid geosynthetic material is basically free of raised areas and / or slits.

19. The method according to claim 17 or 18, characterized in that: (i) The substrate is an asphalt mixture; and / or (ii) The method further includes applying an adhesive layer, preferably asphalt, to the substrate surface before laying the geosynthetic composite material; and / or (iii) The thickness of the asphalt mixture layer is 30~300mm; and / or (iv) The adhesive is bitumen; and / or (v) The average particle size of the aggregate is 5~35mm.

20. The method according to any one of claims 17 to 19, characterized in that, The process of causing the adhesive to solidify includes: (i) Allow the adhesive to cool; and / or (ii) If a solvent is present, the solvent is evaporated.

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