SiO2 aerogel composite geotextile for road and manufacturing method of SiO2 aerogel composite geotextile

Abstract

The invention relates to the field of roadbed engineering design, in particular to SiO2 aerogel composite geotechnical cloth for a road and a manufacturing method. The composite geotechnical cloth comprises a geotechnical cloth base layer and SiO2 aerogel layers, and the SiO2 aerogel layers are located on the upper face and the lower face or the single face of the geotechnical cloth base layer. The aerogel and the geotechnical cloth are combined, the novel aerogel composite geotechnical cloth can be formed, the material not only has the isolation and reinforcement functions of traditional geotechnical cloth, but also has the functions of heat preservation, heat insulation and seepage prevention, the structural integrity and the mechanical property of the aerogel can be spontaneously recovered in the repair cycle through the self-repair function of the aerogel, and the aerogel composite geotechnical cloth can be used as a composite material. The service life can be prolonged and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of roadbed engineering design, and in particular to a road-use SiO 2 Aerogel composite geotextile. Background Art

[0002] Generally, the thickness of the thermal insulation layer of the railway subgrade in cold regions is not less than 10cm, and the thermal conductivity of the insulation material used at 25℃ is not more than 39mW / (m·k); composite geomembranes, capillary drainage boards, rubber synthetic fiber geotextiles, etc. are generally used for subgrade drainage in rainy areas. The above materials are large in size and weight, which makes them inconvenient for transportation and on-site construction. The thermal conductivity of traditional foam plastic insulation layers varies greatly and is not very stable. In addition, the above materials only have a single insulation or anti-seepage function and are highly flammable. There are many deficiencies in performance, function and fire safety. The prevention and control of subgrade frost heave mainly considers the dual protection of drainage and insulation. It is particularly important to study a new type of material that combines insulation, heat insulation, anti-seepage and self-repair functions, is easy to transport and construct, is lightweight and fireproof, in order to keep the subgrade in good working conditions and ensure the inherent safety of the subgrade project.

[0003] In view of this, this case came into being. Summary of the invention

[0004] The purpose of the present invention is to solve the limitation of the single function of the thermal insulation layer of the cold region railway subgrade in the prior art, and the difficulty of transportation and construction, and propose a road-use SiO2 with both thermal insulation, heat insulation, anti-seepage and self-repairing functions. 2 Aerogel composite geotextile and its production method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A road SiO 2 Aerogel composite geotextile, the composite geotextile comprising a geotextile base and SiO 2 Aerogel layer, the SiO 2 The aerogel layer is located on the upper and lower surfaces or on one side of the geotextile base.

[0007] SiO 2 Aerogel is a nano-scale, lightweight, porous, flame-retardant material with excellent hydrophobic, heat-insulating, sound-insulating and environmentally friendly properties. The thermal conductivity at 25°C is no more than 28mW / (m·k). A thin millimeter-level coating can achieve the same insulation effect as ordinary insulation materials at the centimeter level. Due to its hydrophobic properties and closed pore structure, it also has excellent water-proof and drainage properties. SiO 2 The material itself has natural flame retardant properties.

[0008] Therefore, combining aerogel with geotextile can form a new type of aerogel composite geotextile, which not only has the isolation and reinforcement functions of traditional geotextile, but also has thermal insulation and anti-seepage functions, effectively reducing the frost heave or thaw settlement of roadbed in cold areas; at the same time, for rainy areas, abundant groundwater or saline soil areas, it can avoid the occurrence of diseases such as muddy bed, ballast settlement, and salinization of roadbed fillers by blocking the infiltration of surface water or the rise of capillary water. It is particularly suitable for the thermal insulation and anti-seepage layers of roadbeds.

[0009] At the same time, the self-healing function of aerogel spontaneously restores its structural integrity and mechanical properties during the repair cycle, which can extend its service life and reduce maintenance costs.

[0010] Preferably, the SiO 2 The thickness of the aerogel layer is 1-2 mm.

[0011] Preferably, a protective layer is provided above and below the composite geotextile. Specifically, the protective layer is made of coarse sand, non-woven fabric or other drainage materials.

[0012] Preferably, the geotextile base layer is made of polypropylene PP high-strength filament woven geotextile, polyester PET high-strength filament woven geotextile, or a composite geotextile reinforced with non-woven geotextile and basalt fiber.

[0013] Preferably, the vertical permeability coefficient of the geotextile base is not less than 3.5×10 -2 cm / s.

[0014] Preferably, an anti-seepage layer is provided above the composite geotextile. Specifically, the anti-seepage layer is made of HDPE film, and the vertical permeability coefficient is not greater than 1.0×10 -8 cm / s.

[0015] The present invention also provides a road-use SiO 2 Preparation method of aerogel composite geotextile:

[0016] S1. Geotextile base treatment: Dry and remove the hair from the geotextile base to ensure that its surface is clean, hair-free, oil-free and moisture-free;

[0017] S2、SiO 2 Aerogel layer preparation:

[0018] SiO 2 The precursor of the aerogel material is dissolved in water or an organic solvent (such as an inorganic salt or a metal alkoxide) and hydrolyzed under a certain acid or base catalysis to produce primary particles;

[0019] The primary particles condense and grow to form smaller polymers.

[0020] The condensation continues to occur to form large clusters, and further form a three-dimensional network structure to achieve the gel process;

[0021] Calender or spray the gel on both sides or one side of the geotextile base;

[0022] Perform aging and drying treatment on the gel insulation layer to improve its structural strength and stability;

[0023] S3. Processing and molding: The processed geotextile base layer and aerogel insulation layer are formed by hot pressing to form a complete aerogel composite geotextile.

[0024] Compared with the prior art, the present invention provides a road-use SiO 2 Aerogel composite geotextile has the following beneficial effects:

[0025] 1) Adding aerogel to geotextile can significantly improve the overall performance of geotextile, especially tensile strength and elongation at break. Tensile strength: Due to the addition of reinforcing materials, the tensile performance of aerogel reinforced geotextile is much higher than that of conventional geotextile. According to international standards (such as ISO 10319), the tensile strength of aerogel reinforced geotextile can reach 40-60kN / m, while the tensile strength of conventional geotextile is usually around 3-35kN / m, which is a significant improvement compared to the two.

[0026] 2) The addition of aerogel may also make geotextiles have better weather resistance and durability, and maintain stable performance in harsher environments.

[0027] Durability: The nanoporous structure of aerogel gives it a low gas diffusion coefficient, which can effectively block the intrusion of external gases and moisture, thereby reducing the aging and corrosion of the internal materials of the geotextile and extending its service life. The special properties of aerogel materials make the geotextile more stable during long-term use, and its service life is extended by 40-55% compared with conventional geotextiles.

[0028] 3) Thermal insulation: Aerogel has an extremely low thermal conductivity of approximately 0.012W / m·K-0.018W / m·K, which can effectively block low temperatures from the outside, reduce heat loss, and improve the thermal insulation performance of geotextiles. From the perspective of heat conduction, the nanoporous structure of aerogel makes the heat conduction path extremely complex, greatly reducing the efficiency of heat conduction. In building foundation insulation projects in cold areas, aerogel reinforced geotextiles can effectively prevent frost heave of the foundation and protect the stability of the building.

[0029] 4) The self-repairing function of aerogels spontaneously restores their structural integrity and mechanical properties during the repair cycle; self-repairing aerogels can repair themselves after suffering minor damage (such as external force extrusion, temperature difference changes, and extreme low temperature environments), thereby ensuring their structural integrity, the stability of their mechanical properties, and the continued stability of their thermal insulation properties, extending their service life and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a road-use SiO 2 Schematic diagram of the structure of aerogel composite geotextile;

[0031] Figure 2 The present invention is a road-use SiO 2 Process flow chart of the aerogel composite geotextile production method.

[0032] 1. Geotextile base, 2. SiO 2 Aerogel layer, 3. Protective layer. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "lower end", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] Example 1

[0038] like Figure 1-2 A road-use SiO 2 Aerogel composite geotextile, the composite geotextile comprising a geotextile base and SiO 2 Aerogel layer, the SiO 2 The aerogel layer is located on the upper and lower surfaces of the geotextile base.

[0039] The SiO 2 The thickness of the aerogel layer is: 1.0 mm.

[0040] The base layer of geotextile is polypropylene (PP) high-strength filament woven geotextile.

[0041] The thickness of the base fabric is: 0.5mm.

[0042] The longitudinal and transverse tensile strength is: 46kN / m.

[0043] The tearing strength is: 0.22kN.

[0044] CBR bursting strength: 3.5kN.

[0045] Preferably, a protective layer is provided above and below the composite geotextile. Specifically, the protective layer is made of coarse sand to reduce construction damage to the composite geotextile during filler compaction.

[0046] This embodiment is a road-use SiO 2 Preparation method of aerogel composite geotextile:

[0047] S1. Geotextile base treatment: Dry and remove the hair from the geotextile base to ensure that its surface is clean, hair-free, oil-free and moisture-free;

[0048] S2、SiO 2 Aerogel layer preparation: SiO 2 The precursor of the aerogel material is dissolved in water or an organic solvent (such as an inorganic salt or a metal alkoxide) and hydrolyzed under a certain acid or base catalysis to produce primary particles;

[0049] The primary particles condense and grow to form smaller polymers.

[0050] The condensation continues to occur to form large clusters, and further form a three-dimensional network structure to achieve the gel process;

[0051] Calender or spray the gel on both sides or one side of the geotextile base;

[0052] Perform aging and drying treatment on the gel insulation layer to improve its structural strength and stability;

[0053] S3. Processing and molding: The processed geotextile base layer and aerogel insulation layer are formed by hot pressing to form a complete aerogel composite geotextile.

[0054] Example 2

[0055] A road SiO 2 Aerogel composite geotextile, the composite geotextile comprising a geotextile base and SiO 2 Aerogel layer, the SiO 2 The aerogel layer is located on top of the geotextile base layer.

[0056] The SiO 2 The thickness of the aerogel layer is: 1.5 mm.

[0057] The base layer of geotextile is polyester PET high-strength filament woven geotextile.

[0058] The thickness of the base fabric is: 0.75mm.

[0059] The longitudinal and transverse tensile strength is: 52kN / m.

[0060] The tearing strength is: 0.25kN.

[0061] CBR bursting strength: 4.2kN.

[0062] This embodiment is a road-use SiO 2 The method for making the aerogel composite geotextile is the same as that in the first embodiment.

[0063] Example 3

[0064] A road SiO 2 Aerogel composite geotextile, the composite geotextile comprising a geotextile base and SiO 2 Aerogel layer, the SiO 2 The aerogel layer is located below the geotextile base layer.

[0065] The SiO 2 The thickness of the aerogel layer is: 2 mm.

[0066] The geotextile base layer is basalt fiber reinforced composite non-woven geotextile.

[0067] The thickness of the base fabric is: 1mm.

[0068] The longitudinal and transverse tensile strength is: 56kN / m.

[0069] The tearing strength is: 0.3kN.

[0070] CBR bursting strength: 4.8kN.

[0071] This embodiment is a road-use SiO 2 The method for making the aerogel composite geotextile is the same as that in the first embodiment.

[0072] Comparative Example 1: conventional woven geotextile with a thickness of 0.5 mm.

[0073] Comparative Example 2: conventional woven geotextile with a thickness of 0.75 mm.

[0074] Comparative Example 3: conventional non-woven geotextile, thickness 1 mm.

[0075] Geotextiles are tested according to the product standard "Geosynthetics for Railway Engineering" (Q / CR549). The test structure comparison is as follows:

[0076]

[0077]

[0078] Among them, the thickness of Example 1 is the same as that of Comparative Example 1, the thickness of Example 2 is the same as that of Comparative Example 2, and the thickness of Example 3 is the same as that of Comparative Example 3. It can be concluded that, under the condition of the same thickness, the tensile strength, durability and thermal conductivity performance of the embodiments are significantly improved relative to those of the comparative examples.

[0079] It can be seen from the above experiments that the tensile strength, durability and thermal conductivity of Examples 1-3 are relatively good. Compared with the Examples, the Comparative Examples are significantly worse than the Examples in the corresponding performance tests due to the different composition of each component. The above experimental structure further proves the importance of the technical solution defined in the present invention to its technical effect.

[0080] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A SiO2 aerogel composite geotextile for road use, characterized by: The composite geotextile comprises a geotextile base layer and a SiO2 aerogel layer, wherein the SiO2 aerogel layer is located on the upper and lower surfaces or on one side of the geotextile base layer.

2. The SiO2 aerogel composite geotextile for road use according to claim 1, characterized in that: The thickness of the SiO2 aerogel layer is 1-2 mm.

3. The SiO2 aerogel composite geotextile for road use according to claim 1, characterized in that: Protective layers are arranged above and below the composite geotextile.

4. The SiO2 aerogel composite geotextile for road use according to claim 3, characterized in that: The protective layer is made of coarse sand, non-woven fabric or other drainage materials.

5. The SiO2 aerogel composite geotextile for road use according to claim 1, characterized in that: The base layer of geotextile is made of polypropylene PP high-strength filament woven geotextile, polyester PET high-strength filament woven geotextile, or non-woven geotextile plus basalt fiber reinforced composite geotextile.

6. The SiO2 aerogel composite geotextile for road use according to claim 5, characterized in that: The vertical permeability coefficient of the geotextile base is not less than 3.5×10 -2 cm / s.

7. The SiO2 aerogel composite geotextile for road use according to claim 1, characterized in that: An anti-seepage layer is arranged above the composite geotextile.

8. The SiO2 aerogel composite geotextile for road use according to claim 7, characterized in that: The anti-seepage layer is made of HDPE film, and the vertical permeability coefficient is not greater than 1.0×10 -8 cm / s.

9. A method for preparing a road-use SiO2 aerogel composite geotextile according to claims 1-8: S1. Geotextile base treatment: Dry and remove the hair from the geotextile base to ensure that its surface is clean, hair-free, oil-free and moisture-free; Preparation of S2 and SiO2 aerogel layers: The precursor of SiO2 aerogel material is dissolved in water or an organic solvent, and hydrolyzed under a certain acid or base catalysis to produce primary particles; The primary particles condense and grow to form smaller polymers. The condensation continues to occur to form large clusters, and further form a three-dimensional network structure to achieve the gel process; Calender or spray the gel on both sides or one side of the geotextile base; Perform aging and drying treatment on the gel insulation layer to improve its structural strength and stability; S3. Processing and molding: The processed geotextile base layer and aerogel insulation layer are formed by hot pressing to form a complete aerogel composite geotextile.

10. A method for producing a road-use SiO2 aerogel composite geotextile according to claim 8: the organic solvent is an inorganic salt or a metal alkoxide.

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