A waterproof system construction method for repairing a waterproof layer of a ballastless track railway bridge deck

Abstract

The application relates to a waterproof system structure for repairing a waterproof layer of a ballastless track railway bridge deck and a construction method thereof, and the waterproof system structure comprises a bridge deck concrete base layer, a waterproof bottom coating arranged above the bridge deck concrete base layer and a waterproof surface coating coated on the waterproof bottom coating; the waterproof bottom coating is a two-component polyurethane coating, and the waterproof surface coating is an aliphatic polyurethane coating. The waterproof system structure of the application combines the traditional waterproof layer and the surface coating, has the high physical and mechanical properties of the traditional waterproof layer, and has the high weather resistance and aging resistance of the surface coating, so that the requirements of the standards or technical conditions of the waterproof of the ballastless track railway concrete bridge deck in China are met.

Description

Technical Field

[0001] This invention pertains to the repair technology of waterproof layer on ballastless track railway bridge decks, specifically relating to a construction method for a waterproof system used in the repair of waterproof layer on ballastless track railway bridge decks. Background Technology

[0002] Railway concrete bridges are designed for durability, and a waterproof layer must be installed on the bridge deck during construction to prevent rainwater from seeping in and causing accelerated damage and destruction to the bridge structure. This is an important technical means to improve the durability of bridge structures.

[0003] In my country, railway concrete bridges commonly use waterproofing membranes or coatings. Relatively speaking, coatings, as a waterproofing layer, do not suffer from the drawbacks of membranes, such as difficult overlapping, poor adhesion, and unsatisfactory finishing details. Furthermore, the use of high-performance coatings is the development trend for railway concrete bridge deck waterproofing. In the early construction of high-speed railways in my country, high-performance waterproofing coatings were widely used, drawing on international experience. For example, polyurea was extensively used in the waterproofing layers of bridges using CRTS II type slab track. However, during later operation and maintenance, it was found that some polyurea waterproofing layers gradually developed yellowing, damage, and even peeling.

[0004] Currently, maintenance work on operating railways in my country is mainly concentrated during the designated window period, from 0:00 to 4:00 AM, using access gates and stairs for maintenance. Maintenance time is short; after deducting inspection procedures at the access gates, the actual construction time may be less than 3 hours. Furthermore, large machinery cannot be transported to the construction site on the bridge deck via these access gates. Existing waterproofing technical standards for ballastless track railway bridges primarily target newly built railway projects, whose waterproofing systems are complex and have long intervals between construction processes, posing challenges to the repair of defects in the bridge deck waterproofing layer. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a waterproof system structure and construction method for repairing the waterproof layer of ballastless track railway bridge deck, thereby solving the problem of difficult maintenance of the waterproof layer of existing ballastless track bridge deck.

[0006] The technical solution adopted in this invention is:

[0007] A construction method for a waterproofing system used to repair the waterproofing layer of a ballastless track railway bridge deck includes the following steps:

[0008] Clean the original waterproof layer remaining on the concrete base of the bridge deck. Use an impact drill with a flat shovel head to remove it. When removing it, the angle between the flat shovel head and the bridge deck should be less than or equal to 15°. After cleaning, use a disc grinder to clean the surface of the concrete base of the bridge deck, remove the scum, loose soil, hollow, loose, honeycomb pits, and expose a clean and dense concrete base.

[0009] Two-component polyurethane primer is applied to the concrete base layer of the bridge deck as a waterproof primer. The waterproof primer is cured at room temperature. The coating amount is greater than or equal to 0.4 kg / m², and the surface drying time is 60~90 min.

[0010] Apply an aliphatic polyurethane topcoat as a waterproof topcoat on the already surface-dried waterproof primer. The waterproof topcoat is cured at room temperature. The coating amount is greater than or equal to 0.8 kg / m², and the surface drying time is 90~120 min.

[0011] The waterproof primer and waterproof topcoat are applied within the same time window.

[0012] Furthermore, it also includes the original waterproof layer. After removing the defects in the original waterproof layer, a bevel is formed on the original waterproof layer, and the edge of the waterproof primer layer overlaps on the bevel.

[0013] Furthermore, a crash barrier or water barrier is installed at one end of the concrete base layer of the bridge deck, and a waterproof primer is applied to the crash barrier or water barrier at a height of 5-15cm.

[0014] Furthermore, rainwater pipes are installed on the concrete base layer of the bridge deck, and the waterproof primer is applied from the concrete base layer of the bridge deck to the inner wall of the rainwater pipe, extending 3-7cm into the rainwater pipe.

[0015] The positive effects of this invention are:

[0016] The waterproofing system of this invention combines a traditional waterproofing layer and a topcoat, possessing both the high physical and mechanical properties of the traditional waterproofing layer and the high weather resistance and aging resistance of the topcoat, thus meeting the requirements of my country's standards or technical conditions for waterproofing concrete bridge decks on ballastless railway tracks. Construction requires no large equipment; it can be completed using traditional small tools, addressing situations where large equipment and tools cannot be carried during bridge deck repairs.

[0017] Meanwhile, the waterproofing system of this invention has a simplified structure with no redundant design, reducing construction steps and making construction more convenient and efficient. It is especially suitable for maintenance and construction during the window period of railway operation, making maintenance simpler and more convenient. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of Embodiment 4 of the present invention;

[0022] Figure 5 This is a schematic diagram of the structure of Embodiment 5 of the present invention. Detailed Implementation

[0023] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided. Example

[0024] This embodiment discloses a waterproofing system structure for repairing the waterproofing layer of a ballastless track railway bridge deck, as shown in the attached diagram. Figure 1 As shown, it includes a bridge deck concrete base layer 1, a waterproof primer layer 2 disposed on the bridge deck concrete base layer 1, and a waterproof topcoat layer 3 disposed on the waterproof primer layer 2.

[0025] Waterproof primer 2 is a two-component polyurethane primer with a coating amount of ≥0.4kg / ㎡. It is preferably made of aliphatic isocyanate, which has good weather resistance, small quantity, and strong penetration.

[0026] The waterproof topcoat 3 is a high-performance aliphatic polyurethane topcoat that is cured at room temperature. The coating amount is ≥0.8kg / ㎡, the dry film thickness is ≤0.6mm, the tensile strength is ≥10MPa, and the elongation at break is ≥300%. The waterproof topcoat formed by this curing process combines the high physical and mechanical properties of the waterproof layer in the traditional waterproof system with the high weather resistance and aging resistance of the topcoat. Example

[0027] This embodiment addresses situations where the original waterproofing layer of a railway bridge deck suffers only minor damage, requiring only localized repairs. (See attached image.) Figure 2 As shown, this embodiment also includes the original waterproof layer 5 based on embodiment 1. When removing the original waterproof layer 5 around the defect using an impact drill with a flat shovel head, the removal should be done inwards to preserve the original waterproof layer 5 without defects. A bevel 4 is formed on the original waterproof layer 5. The waterproof base coating 2 is then overlapped with the bevel 4 during subsequent repair to form an integral waterproof layer. Example

[0028] This embodiment is a further limitation based on embodiment 2, as shown in the appendix. Figure 3 As shown, when the defect point is located near the base plate 6, the waterproof primer 2 and waterproof topcoat 3 are not applied to the base plate 6, but are overlapped with the original waterproof layer under the base plate by forming a bevel 4. Example

[0029] As attached Figure 4As shown, this embodiment is applicable to the location of the wall crash barrier or water barrier 7. In this case, the waterproof primer 2 and waterproof topcoat 3 need to be applied to the crash barrier or water barrier, with a height of 5-15cm, preferably about 10cm. Example

[0030] As attached Figure 5 As shown, this embodiment is applicable to the case where a rainwater pipe 8 is installed on the concrete base layer 1 of the bridge deck. In this case, the waterproof primer coating 2 and the waterproof topcoat coating 3 need to be applied from the concrete base layer 1 of the bridge deck to the inner wall of the rainwater pipe 8, extending into the rainwater pipe 8 pipe by 3-7cm, preferably 5cm. The waterproof primer coating 2 and the waterproof topcoat coating 3 inside the rainwater pipe 8 should be made appropriately thin to facilitate the installation of the rainwater pipe cover. Example

[0031] This embodiment provides a construction method for a waterproofing system used to repair the waterproofing layer of a ballastless track railway bridge deck, specifically including the following steps:

[0032] S1: Apply a two-component polyurethane primer as a waterproof base layer to the concrete base of the bridge deck;

[0033] S2: Apply a high-performance aliphatic polyurethane topcoat as a waterproof topcoat over the surface-dried waterproof primer.

[0034] Before step S1, surface treatment of the bridge deck concrete base 1 is performed. Specifically, the original waterproof layer 5 remaining on the surface of the bridge deck concrete base 1 should be removed using an impact drill with a flat shovel head. During removal, the angle between the flat shovel head and the bridge deck should not exceed 15° to prevent damage to the bridge deck concrete base. After the original waterproof layer 5 is removed, a disc grinder should be used to clean the surface of the bridge deck concrete base, removing surface debris, loose soil, hollow areas, loose areas, and honeycomb pits, exposing a clean and dense concrete base.

[0035] After the concrete base layer of the bridge deck is thoroughly cleaned, a waterproof primer should be applied to the drainage outlets, corners, and vertical walls using a brush, and a waterproof primer should be applied to large areas using a roller brush. The waterproof primer should be applied evenly by roller or brush, ensuring no bare spots are exposed and no areas are piled up.

[0036] Waterproof primer layer 2 is a two-component polyurethane primer that cures at room temperature. Its application rate should be no less than 0.4 kg / m², and the surface drying time should ideally be between 60 and 90 minutes. Aliphatic isocyanates are preferred for the polyurethane primer due to their good weather resistance, small quantity, and strong penetration. Before use, the two-component polyurethane primer should be gently stirred until homogeneous. The components should be accurately weighed and prepared according to the instructions in the product manual, and should be used immediately after preparation. After weighing, the primer should be thoroughly stirred until homogeneous. It is advisable to use a vacuum degassing method to de-foam the mixed primer before applying it by roller or brush.

[0037] After the second waterproof primer layer is applied, it should be allowed to stand for a sufficient time, and the waterproof topcoat should only be applied after confirming that the primer is surface dry. It is advisable to use a brush to apply the waterproof topcoat to areas such as bridge deck drainage outlets, corners, and vertical walls, and a roller brush to apply the waterproof topcoat to large areas. The waterproof topcoat should be applied evenly by roller or brush, and should not run, expose the substrate, scratch, crack, peel, or blister.

[0038] Waterproof topcoat 3 is a high-performance aliphatic polyurethane topcoat that cures at room temperature. Its application rate should be no less than 0.8 kg / m², and the surface drying time should ideally be between 90 and 120 minutes. The topcoat should preferably be a high-performance aliphatic polyurethane topcoat with a tensile strength ≥10 MPa and an elongation at break ≥300%. This type of cured waterproof topcoat combines the high physical and mechanical properties of the waterproof layer in traditional waterproofing systems with the high weather resistance and aging resistance of the topcoat.

[0039] The construction of the concrete base layer for the bridge deck should ideally be completed within one or more window periods. The waterproof primer and topcoat should ideally be completed within the same window period. This effectively avoids the impact of dust raised by trains and subsequent rain and condensation on the quality of the waterproofing layer during multi-window construction. After the topcoat is completed, sufficient time should be allowed before the train reaches the repair site, preferably until the topcoat is surface dry, to minimize the impact of dust and debris carried by the train on the waterproofing system.

[0040] The two-component polyurethane primer and high-performance aliphatic polyurethane topcoat involved in this invention have been widely used in different construction processes and other anti-corrosion fields. However, the combination of the two materials as a waterproof layer for ballastless bridge deck repair is a first, and it has been applied in the bridge deck repair test section with good results.

[0041] Compared with the existing technology, the present invention has the following advantages:

[0042] (1) It combines the traditional waterproof layer and the topcoat layer into one, which has the high physical and mechanical properties of the traditional waterproof layer and the high weather resistance and aging resistance of the topcoat layer, thus meeting the requirements of the standards or technical conditions for waterproofing of concrete bridge decks of ballastless railway in my country.

[0043] (2) The structure is simplified and there is no redundant design, which reduces the construction process, makes construction more convenient and efficient, and is especially suitable for maintenance and construction during the window period of operating railways.

[0044] (3) The waterproof base coat and waterproof top coat can be completed within one window period, avoiding the impact of environmental factors such as dust brought up by train operation, rainwater, and condensation on the construction quality of the waterproof layer during multi-window construction. The error tolerance is higher and the construction quality is more stable.

[0045] (4) No large equipment is required for construction; traditional small tools can be used to complete the work, which meets the requirements of bridge deck repair where large equipment and tools cannot be carried.

[0046] (5) The waterproof primer coating is made of aliphatic isocyanate, which has good weather resistance and small weight. Compared with traditional primer coatings, it has stronger permeability to cement substrates, which can greatly improve the bonding strength between waterproof materials and concrete substrates and extend service life.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for a waterproofing system for repairing the waterproofing layer of a ballastless track railway bridge deck, characterized in that... It includes the following steps: Clean the original waterproof layer (5) remaining on the concrete base layer (1) of the bridge deck. Use an impact drill with a flat shovel head to remove it. When removing it, the angle between the flat shovel head and the bridge deck should be less than or equal to 15°. After cleaning, use a disc grinder to clean the surface of the concrete base layer of the bridge deck. Remove the floating slag, loose soil, hollow, loose, honeycomb pitted surface, and expose a clean and dense concrete base layer. Two-component polyurethane primer was applied to the concrete base layer (1) of the bridge deck as a waterproof primer (2). The waterproof primer (2) was cured at room temperature. The coating amount was greater than or equal to 0.4 kg / m², and the surface drying time was 60~90 min. Apply an aliphatic polyurethane topcoat as a waterproof topcoat (3) on the already surface-dried waterproof primer (2). The waterproof topcoat (3) is cured at room temperature. The coating amount is greater than or equal to 0.8 kg / m², and the surface drying time is 90~120 min. The waterproof primer (2) and waterproof topcoat (3) were applied within the same window period.

2. The construction method of a waterproofing system for repairing the waterproofing layer of a ballastless track railway bridge deck according to claim 1, characterized in that... It also includes the original waterproof layer (5), after removing the defects of the original waterproof layer (5), a bevel (4) is formed on the original waterproof layer (5), and the edge of the waterproof base layer (2) overlaps on the bevel (4).

3. The construction method of a waterproofing system for repairing the waterproofing layer of a ballastless track railway bridge deck according to claim 1, characterized in that... A crash barrier or water barrier (7) is provided at one end of the concrete base layer (1) of the bridge deck, and a waterproof primer (2) is applied to the crash barrier or water barrier (7) at a height of 5-15cm.

4. The construction method of a waterproofing system for repairing the waterproofing layer of a ballastless track railway bridge deck according to claim 1, characterized in that... A rainwater pipe (8) is installed on the concrete base layer (1) of the bridge deck. The waterproof base coating (2) is applied from the concrete base layer (1) of the bridge deck to the inner wall of the rainwater pipe (8) and extends into the rainwater pipe (8) by 3-7 cm.

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