UHPFRC composite steel bridge deck with cold spliced keys

Abstract

A kind of UHPFRC combined steel bridge deck panel using burl cold connection key, comprising the following construction steps: S1, prefabricated cold connection key;S2, using high-pressure air gun to carry out dust removal, cleaning to steel bridge deck top plate;S3, set cold connection key on steel bridge deck top plate, the longitudinal distance between adjacent cold connection key is 30-50cm, the transverse distance is 30-50cm;S4, pours the layer of ultra-high performance cement-based composite material on steel bridge deck top plate and cold connection key;The combined steel bridge deck panel of the application is simple in structure, and the force is clear, burl cold connection key is used in steel-mix combined structure, increases the contact area of connection key and concrete, can significantly reduce the stress concentration between connection key and concrete, while connection key has 360 degrees universal shear resistance, and shear resistance adaptability is good, and has good tensile performance, reliable connection and other advantages, is used with copolymerized formaldehyde fiber or hybrid fiber UHPFRC, can significantly improve the combined stiffness of combined structure, improves the fatigue performance of steel bridge deck panel.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, specifically relating to a UHPFRC composite steel bridge deck using bamboo-joint cold-connection keys. Background Technology

[0002] Steel-concrete composite structures combine steel and concrete structures through shear keys to work together. The construction form and force transmission mechanism of the shear keys are key factors affecting the stress and safety of the composite structure.

[0003] Currently, shear keys used in steel-concrete structures mainly include "stud keys," "PBL keys," "steel profile keys," "reinforcing bar keys," and "composite keys." These existing steel-concrete composite structure keys still have some unresolved technical problems, such as: stud keys and other welded keys, due to their own structure and welding process, are prone to stress concentration between the key and the concrete, preventing them from fully functioning; some keys have large differences in longitudinal and transverse shear strength and poor shear adaptability; some keys have poor pull-out resistance and are not good at resisting vertical separation of concrete from the steel bridge deck; and "composite keys" have insufficient durability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a UHPFRC composite steel bridge deck with bamboo-joint cold connection key, which has a reasonable design, 360-degree universal shear resistance of the connection key, good shear adaptability, can effectively improve the shear and pull-out performance of steel-concrete composite structures, and effectively improve the stiffness of the composite structure.

[0005] The technical solution adopted to solve the above technical problems is: a UHPFRC composite steel bridge deck using bamboo-joint cold-connection keys, including the following construction steps:

[0006] S1, Pre-cooling connection key; the pre-cooling connection key consists of a stud and a casting, with the stud located inside the casting; the casting is made of ultra-high performance cement-based composite material;

[0007] S2. Use a high-pressure air gun to remove dust and clean the top plate of the steel bridge deck;

[0008] S3. Cold connection keys are installed on the top plate of the steel bridge deck. The longitudinal distance between adjacent cold connection keys is 30-50cm, and the transverse distance is 30-50cm.

[0009] S4. Arrange the steel mesh and pour an ultra-high performance cement-based composite material layer on the top plate of the steel bridge deck and the cold connection key.

[0010] The cold-connect key of the present invention is bonded to the top plate of the steel bridge deck with structural adhesive.

[0011] The thickness of the structural adhesive in this invention is 1.5 to 3 mm.

[0012] The casting component of this invention comprises 1 to 3 bamboo sections. Each bamboo section consists of a cylindrical body and a circumferential protrusion located in the middle of the cylindrical body. The circumferential protrusion is formed by four smoothly connected arc segments a, b, c, and d. The arcs formed by connecting arc segments a and b and arc segments c and d are symmetrically arranged about the height direction of the cylindrical body. The radius of arc segments a and d is 12 to 16 mm and the central angle is 0.18π to 0.24π. The radius of arc segments b and c is 5 to 8 mm and the central angle is 0.22π to 0.26π. The diameter of the cylindrical body is 80 to 150 mm and the height is 50 to 80 mm.

[0013] The studs of this invention have a diameter of 8-16 mm and a height that is 10 mm lower than that of the cast part.

[0014] The adjacent rows of cold connection keys of the present invention are arranged parallel to each other on the top plate of the steel bridge deck.

[0015] The adjacent rows of cold connection keys of the present invention are arranged in a crisscross pattern on the top plate of the steel bridge deck.

[0016] The casting component and the stud are concentrically arranged in this invention.

[0017] The ultra-high performance cement-based composite material of the present invention is a copolymerized formaldehyde fiber ultra-high performance cement-based composite material, wherein the 1m 3 The copolymerized formaldehyde fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio:

[0018]

[0019] The cement is P.O42.5 ordinary Portland cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of standard sand or river sand is less than 0.8mm; water-reducing agent component A is 3301c type high-efficiency water-reducing agent; water-reducing agent component B is microsphere powder, used in combination with the water-reducing agent component A; the copolymerized formaldehyde fiber has a length of 12mm, a diameter of 200μm, an elastic modulus of 10GPa, a breaking strength of 7.0~8.5cN / dtex, and a breaking elongation of 13~15%.

[0020] The ultra-high performance cement-based composite material of the present invention is a hybrid fiber ultra-high performance cement-based composite material, wherein the 1m 3 The hybrid fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio:

[0021]

[0022]

[0023] The copolymerized formaldehyde fiber has a length of 12 mm, a diameter of 200 μm, an elastic modulus of 10 GPa, a tensile strength of 7.0–8.5 cN / dtex, and an elongation at break of 13%–15%. The steel fiber is copper-plated, has a length of 13 mm, and a diameter of 0.2 mm. The silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; Water-reducing agent A is 3301c type high-efficiency water-reducing agent; Water-reducing agent B is microsphere powder, which is used in combination with water-reducing agent A; Cement is P.O42.5 ordinary Portland cement; The maximum particle size of standard sand or river sand is less than 0.8mm.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention uses a stud-bamboo-joint UHPFRC casting component to form a composite connection key. The stud and UHPFRC casting component materials can work synergistically to give full play to their advantages. The UHPFRC casting component can increase the contact area between the connection key and the concrete, effectively reducing the stress concentration in the concrete.

[0026] 2. The UHPFRC casting component of the present invention has a bamboo-joint structure. This structure enhances the mechanical interlocking force between the connecting key and the ultra-high performance cement-based composite material layer, giving the connecting key good pull-out resistance and ensuring the overall mechanical properties of the composite structure.

[0027] 3. The composite connecting key of the present invention provides 360-degree universal shear resistance and excellent shear adaptability. Simultaneously, the restraining effect of the UHPFRC casting on the studs further enhances the shear resistance of the connecting key.

[0028] 4. The casting component and the ultra-high performance cement-based composite material layer of the present invention are made of copolymerized formaldehyde fiber or hybrid fiber ultra-high performance cement-based composite material. The copolymerized formaldehyde fiber or hybrid fiber ultra-high performance cement-based composite material has high compressive and tensile strength, good fluidity, self-compacting and wear resistance. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention.

[0030] Figure 2 yes Figure 1 A schematic diagram of the structure of the intercooler connection key 2.

[0031] Figure 3 This is a photograph of the extent of the implementation of Example 1.

[0032] Figure 4The image shows the failure morphology of a cubic compression specimen aged 14 days in Example 1.

[0033] Figure 5 The image shows the failure morphology of a cubic compression specimen aged 28 days in Example 1.

[0034] Figure 6 This is a photograph of the specimen after a 14-day bending test in Example 1.

[0035] Figure 7 This is a photograph of the specimen after the bending test at 28 days of age in Example 1.

[0036] Figure 8 The image shows the failure morphology of a cubic compression specimen aged 28 days in Example 2.

[0037] Figure 9 This is a photograph of the extent of the invention in Embodiment 4.

[0038] Figure 10 This is a photograph of the failure morphology of a cubic compression specimen aged 14 days in Example 4 of the present invention.

[0039] Figure 11 This is a photograph of a cube compression test conducted at an age of 28 days, as described in Example 4 of this invention.

[0040] Figure 12 This is a photograph of the specimen after a 14-day bending test in Example 4 of this invention.

[0041] Figure 13 This is a photograph of the specimen after a 28-day bending test in Example 5 of this invention.

[0042] In the figure: 1. Steel bridge deck top plate; 2. Cold connection key; 3. Ultra-high performance cement-based composite material layer; 4. Structural adhesive; 2-1. Stud; 2-2. Cast-in-place component. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

[0044] Note: UHPFRC in this article refers to ultra-high performance cement-based composite materials.

[0045] Example 1

[0046] exist Figure 1 , 2 The present invention relates to a UHPFRC composite steel bridge deck using bamboo-joint cold-connection keys, comprising the following construction steps:

[0047] S1, Pre-cooling connecting key 2; The pre-cooling connecting key 2 consists of a stud 2-1 and a casting component 2-2. The stud 2-1 is located inside the casting component 2-2 and is concentrically arranged with the casting component 2-1. The casting component 2-2 is made of ultra-high performance cement-based composite material. In this embodiment, the casting component 2-2 contains two bamboo sections. Depending on the actual working conditions, the casting component 2-2 may contain one or three bamboo sections. Each bamboo section consists of a cylindrical body and a circumferential protrusion located in the middle of the cylindrical body. The circumferential protrusion is formed by four smoothly connected arc segments a, b, c, and d. The arcs formed by the connection of arc segments a and b, and the arcs formed by the connection of arc segments c and d, are symmetrically arranged about the height of the cylindrical body. The radius of arc segments a and d is 12-16 mm, and the central angle is 0.18π-0.24π. The radius of arc segments b and c is 5-8 mm, and the central angle is 0.22π-0.26π. The diameter of the cylindrical body is 80-150 mm, and the height is 50-80 mm. The diameter of pin 1 is 8-16 mm, and the height is 40-70 mm. The height of pin 2-1 must be 10 mm lower than the height of the cylindrical body.

[0048] S2. Use a high-pressure air gun to remove dust and clean the top plate 1 of the steel bridge deck.

[0049] S3. Cold-connecting keys 2 are provided on the top plate 1 of the steel bridge deck. The longitudinal distance between adjacent cold-connecting keys 2 is 30-50cm, and the transverse distance is 30-50cm. Specifically, in this embodiment, the cold-connecting keys 2 are bonded to the top plate 1 of the steel bridge deck using structural adhesive 4, and the thickness of the structural adhesive is 1.5-3mm. Further, in order to ensure the overall mechanical performance of the composite structure, adjacent rows of cold-connecting keys 2 are arranged parallel to each other on the top plate 1 of the steel bridge deck, or adjacent rows of cold-connecting keys 2 are arranged alternately on the top plate 1 of the steel bridge deck.

[0050] S4. Arrange the steel mesh and pour the ultra-high performance cement-based composite material layer 3 on the top plate 1 and cold connection key 2 of the steel bridge deck.

[0051] In this embodiment, the casting component 2-2 has a bamboo-joint structure. This structure enhances the mechanical interlocking force between the connecting key and the ultra-high performance cement-based composite material layer, giving the connecting key good pull-out resistance and ensuring the overall mechanical properties of the composite structure. The combined use of the cold connecting key 2 and the ultra-high performance cement-based composite material layer 3 can significantly improve the combined stiffness of the composite structure and enhance the fatigue performance of the steel bridge deck.

[0052] The ultra-high performance cement-based composite material in this embodiment is a copolymerized formaldehyde fiber ultra-high performance cement-based composite material, with a 1m 3 Taking the copolymerized formaldehyde fiber ultra-high performance cement-based composite material as an example, in 1m 3 The copolymerized formaldehyde fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio:

[0053]

[0054] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume particle size distribution ranges from 0.1 to 0.15 μm, and the specific surface area is 15 to 27 m². 2 / g; maximum particle size of river sand is less than 0.8mm; water-reducing agent A is 3301c type high-efficiency water-reducing agent; water-reducing agent B is microsphere powder, and components A and B are used in combination; the specifications of the copolymerized polyoxymethylene fiber are 12mm in length, 200μm in diameter, elastic modulus of 10GPa, tensile strength of 7.0~8.5cN / dtex, and elongation at break of 13~15%.

[0055] Its preparation method is as follows:

[0056] S1. Weigh out each dry powder material and copolymerized formaldehyde fiber according to the mixing ratio. Add cement, river sand, silica fume, water-reducing agent B component and copolymerized formaldehyde fiber to a planetary mixer in sequence. Dry mix for 8-11 minutes until the copolymerized formaldehyde fiber and dry powder materials are evenly mixed to make dry material.

[0057] S2. Add half of the water-reducing agent component A and water to the dry material in sequence and stir at a constant speed for 1 to 2 minutes;

[0058] S3. Add the remaining half of the water-reducing agent component A and water to the dry material and stir at a constant speed for 1-2 minutes until the mixture is homogeneous.

[0059] S4. Continue stirring for 4 to 6 minutes. When the mixture is evenly mixed and has good fluidity, it can be discharged and stirring can be stopped.

[0060] The inventors conducted scalability tests, compressive strength tests, and flexural strength tests on the copolymerized formaldehyde fiber ultra-high performance cement-based composite material prepared in Example 1 of this invention. The test results are as follows:

[0061] 1. Slump and spread test

[0062] Using the material proportions and preparation method of Example 1 of this invention, and in accordance with the "Test Method for Slump of Concrete" (JIS A1101-2005), a slump test was conducted on the mixed copolymerized polyoxymethylene fiber ultra-high performance cementitious composite material. After the test, the mixed copolymerized polyoxymethylene fiber ultra-high performance cementitious composite material was observed to have good fluidity, with an expansion diameter reaching 42.6 cm. The test results are shown in […]. Figure 3 .

[0063] 2. Compressive strength test

[0064] Using the material proportions and preparation method of Example 1 of this invention, one set of cubic specimens with dimensions of 100mm × 100mm × 100mm (length × width × height) were prepared. One specimen was cured for 14 days, and two specimens were cured for 28 days. Another set of cubic specimens with dimensions of 150mm × 150mm × 150mm (length × width × height) consisted of three specimens. All specimens were cured at room temperature under conditions of plastic film and damp cotton. The cubic compressive strength of the specimens was tested using a universal compression tester according to the test method of the "Standard for Testing and Evaluation of Concrete Strength" (GB50107-2010).

[0065] The test results show that: in Group 1, the average cubic compressive strength of one specimen aged 14 days was 105.2 MPa, which is equivalent to 100 MPa in a 150 mm standard specimen. The average cubic compressive strength of the two specimens aged 28 days was 95.8 MPa after conversion. The failure modes of the specimens after the test are as follows: Figure 4 As shown; the average cubic compressive strength of group 2 was 95.8 MPa, and the failure mode of the specimens after the test was as follows. Figure 5 As shown;

[0066] The highest strength grade of concrete, C80, in the "Code for Design of Concrete Structures" corresponds to a compressive strength of 80 MPa. The compressive strength of the specimens in this invention is much higher than the compressive strength of the highest strength grade in the "Code for Design of Concrete Structures". Therefore, this invention uses a combination of a cast ultra-high performance cement-based composite material layer 3 and a cold connection key 2 to form a composite steel bridge deck, which has a high compressive strength.

[0067] 3. Bending test

[0068] A set of four flexural specimens (length × width × thickness 500 mm × 100 mm × 50 mm) were prepared using the material ratio and preparation method of Example 1 of this invention. One specimen was cured for 14 days, and the other three were cured for 28 days. All specimens were cured at room temperature under a plastic film and a damp cotton blanket. The flexural strength of the specimens was tested using a SANS MTS testing machine. Before the test, strain gauges were placed at the bottom test section of the specimen, and the XTXDIC (three-dimensional full-field strain measurement system) was placed at the calculation position directly in front of the specimen. The flexural test was performed on the specimens according to the equipment operation method. Post-test photographs are shown below. Figure 6 , 7 .

[0069] The test results show that the flexural strength of the specimens cured for 14 days was 14.3 MPa, and the average flexural strength of the specimens cured for 28 days was 13.4 MPa. The "Design Standard for Steel Fiber Reinforced Concrete Structures" requires that the flexural tensile strength of the steel fiber reinforced concrete pavement layer in bridge decks be no less than 5.5 MPa. The flexural strength of the above specimens is far higher than the requirement of the "Design Standard for Steel Fiber Reinforced Concrete Structures". Therefore, this invention uses a cast ultra-high performance cement-based composite material layer 3 combined with cold-connected keys 2 to form a composite steel bridge deck, which has high flexural tensile strength.

[0070] Example 2

[0071] With 1m 3 Taking the copolymerized formaldehyde fiber ultra-high performance cement-based composite material as an example, in 1m 3 The copolymerized formaldehyde fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio:

[0072]

[0073] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume particle size distribution ranges from 0.1 to 0.15 μm, and the specific surface area is 15-27 m². 2 / g; maximum particle size of river sand is less than 0.8mm; water-reducing agent A is 3301c type high-efficiency water-reducing agent; water-reducing agent B is microsphere powder, and components A and B are used in combination; the specifications of the copolymerized polyoxymethylene fiber are 12mm in length, 200μm in diameter, elastic modulus of 10GPa, tensile strength of 7.0~8.5cN / dtex, and elongation at break of 13~15%.

[0074] The preparation method is the same as in Example 1.

[0075] The inventors conducted flexural strength tests on the copolymerized formaldehyde fiber ultra-high performance cement-based composite material prepared in Example 2 of this invention. The test results are as follows:

[0076] 1. Bending test

[0077] A set of three flexural specimens (length × width × thickness 500 mm × 100 mm × 50 mm) were prepared using the material ratio and preparation method of Example 1 of this invention. All specimens were cured at room temperature for 28 days under a plastic film and a damp cotton blanket. The flexural strength of the specimens was tested using a SANS MTS testing machine. Before the test, strain gauges were placed at the bottom test section of the specimen, and the XTXDIC (three-dimensional full-field strain measurement system) was placed at the calculation position directly in front of the specimen. The flexural test was performed on the specimens according to the equipment operation method. Post-test photographs are shown below. Figure 8 .

[0078] The test results show that the average flexural strength of the specimens cured for 28 days is 11.6 MPa. The flexural strength of the specimens of this invention is much higher than the requirements of the "Design Standard for Steel Fiber Reinforced Concrete Structures". Therefore, this invention uses a combination of a cast ultra-high performance cement-based composite material layer 3 and a cold-connected key 2 to form a composite steel bridge deck, which has high flexural strength.

[0079] Example 3

[0080] With 1m 3 Taking the copolymerized formaldehyde fiber ultra-high performance cement-based composite material as an example, in 1m 3 The copolymerized formaldehyde fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio:

[0081]

[0082] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume particle size distribution ranges from 0.1 to 0.15 μm, and the specific surface area is 15-27 m². 2 / g; the maximum particle size of the standard sand is less than 0.8mm; water-reducing agent A is 3301c type high-efficiency water-reducing agent; water-reducing agent B is microsphere powder, and components A and B are used in combination; the specifications of the copolymerized polyoxymethylene fiber are 12mm in length, 200μm in diameter, 10GPa in elastic modulus, 7.0~8.5cN / dtex in tensile strength, and 13~15% in elongation at break.

[0083] The preparation method is the same as in Example 1.

[0084] Example 4

[0085] In this embodiment, the ultra-high performance cement-based composite material is a hybrid fiber ultra-high performance cement-based composite material, with a 1m 3 Taking hybrid fiber ultra-high performance cement-based composite materials as an example, in 1m 3 The hybrid fiber ultra-high performance cementitious composite material is composed of materials in the following mass ratio:

[0086]

[0087] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of the river sand is less than 0.8mm; the water-reducing agent A component is a 3301c type high-efficiency water-reducing agent; the water-reducing agent B component is microsphere powder, which is used in combination with the water-reducing agent A component; the copolymerized formaldehyde fiber has a length of 12mm, a diameter of 200μm, an elastic modulus of 10GPa, a breaking strength of 7.0~8.5cN / dtex, and a breaking elongation of 13~15%; the steel fiber is copper-plated steel fiber with a length of 13mm and a diameter of 0.2mm.

[0088] Its preparation method is as follows:

[0089] S1. Weigh out the dry powder materials and copolymerized polyoxymethylene fiber according to the corresponding mix proportions. Add cement, river sand, silica fume, water-reducing agent B component and copolymerized polyoxymethylene fiber into the DMPC convection planetary mixer in sequence. Dry mix for 8 to 11 minutes until the copolymerized polyoxymethylene fiber is evenly mixed with the remaining dry materials.

[0090] S2. Add half of the water-reducing agent component A and water to the dry material in sequence and stir at a constant speed for 1 to 2 minutes.

[0091] S3. Add the remaining half of the water-reducing agent component A and water to the dry material and stir at a constant speed for 1 to 2 minutes until the mixture is uniform.

[0092] S4. Add steel fibers and continue stirring for 4-6 minutes until the mixture is homogeneous and its fluidity meets the test requirements before discharging.

[0093] The inventors conducted slump and spread tests, compressive strength tests, and flexural strength tests on the hybrid fiber ultra-high performance cement-based composite material prepared using the above formula. The test results are as follows:

[0094] 1. Slump and spread test

[0095] Using the above-mentioned material proportions and preparation methods, slump tests were conducted on the mixed hybrid fiber ultra-high performance cementitious composite material according to the "Test Method for Slump of Concrete" (JIS A1101-2005). After the test, the mixed hybrid fiber ultra-high performance cementitious composite material was observed to have good fluidity, with a spread diameter reaching 49.5 cm. The test results are shown in [Figure number missing]. Figure 9 .

[0096] 2. Compressive strength test

[0097] Using the above-mentioned material proportions and preparation methods, one set of three cubic specimens with dimensions of 100mm × 100mm × 100mm (length × width × height) were prepared, with one specimen cured for 14 days and the other two for 28 days. Another set of three cubic specimens with dimensions of 150mm × 150mm × 150mm were also prepared. All specimens were cured at room temperature under conditions of plastic film and damp cotton blankets. The cubic compressive strength of the specimens was tested using a universal compression tester according to the test methods in the "Standard for Testing and Evaluation of Concrete Strength" (GB50107-2010).

[0098] The test results show that: in Group 1, the average cubic compressive strength of one specimen aged 14 days was 109.9 MPa, which is equivalent to 104.4 MPa for a 150 mm standard specimen; the average cubic compressive strength of the two specimens aged 28 days was 114.7 MPa, which is equivalent to 109.0 MPa for a 150 mm standard specimen. The failure modes of the specimens after the test are as follows: Figure 10 As shown; the average cubic compressive strength of group 2 is 98.4 MPa, and the test photograph is as follows. Figure 11 As shown, the average cubic compressive strength of the two groups of specimens differs significantly, indicating that the hybrid fiber ultra-high performance cementitious composite material has a large size effect.

[0099] The highest strength grade of concrete, C80, in the "Code for Design of Concrete Structures" corresponds to a compressive strength of 80 MPa. The compressive strength of the specimens in this invention is much higher than the compressive strength of the highest strength grade in the "Code for Design of Concrete Structures". Therefore, this invention uses a combination of a cast ultra-high performance cement-based composite material layer 3 and a cold connection key 2 to form a composite steel bridge deck, which has a high compressive strength.

[0100] 3. Bending test

[0101] One set of bending test specimens, measuring 500mm × 100mm × 50mm (length × width × thickness), was prepared using the above-mentioned material ratio and preparation method. The specimen was covered with plastic film and a damp cotton blanket for 14 days at room temperature for curing. The bending strength of the specimen was tested using a SANS MTS testing machine. Before the test, strain gauges were placed at the bottom test section of the specimen, and the XTXDIC (3D full-field strain measurement system) was placed at the calculation position directly in front of the specimen. The bending test was performed on the specimen according to the equipment operation instructions. Post-test photographs are shown below. Figure 12 .

[0102] The test results show that the flexural strength of the specimen after 14 days of curing is 12.9 MPa. The "Design Standard for Steel Fiber Reinforced Concrete Structures" requires that the flexural strength of the steel fiber reinforced concrete pavement layer of the bridge deck should not be less than 5.5 MPa. The flexural strength of the specimen of this invention is much higher than the requirement of the "Design Standard for Steel Fiber Reinforced Concrete Structures". Therefore, this invention uses a combination of cast ultra-high performance cement-based composite material layer 3 and cold connection key 2 to form a composite steel bridge deck, which has high flexural strength.

[0103] Example 5

[0104] With 1m 3 Taking hybrid fiber ultra-high performance cement-based composite materials as an example, in 1m 3 The hybrid fiber ultra-high performance cementitious composite material is composed of materials in the following mass ratio:

[0105]

[0106] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of the river sand is less than 0.8mm; the water-reducing agent A component is a 3301c type high-efficiency water-reducing agent; the water-reducing agent B component is microsphere powder, which is used in combination with the water-reducing agent A component; the copolymerized formaldehyde fiber has a length of 12mm, a diameter of 200μm, an elastic modulus of 10GPa, a breaking strength of 7.0~8.5cN / dtex, and a breaking elongation of 13~15%; the steel fiber is copper-plated steel fiber with a length of 13mm and a diameter of 0.2mm.

[0107] Its preparation method is the same as that in Example 4.

[0108] The inventors used the hybrid fiber ultra-high performance cement-based composite material prepared in Example 5 of this invention. The flexural strength was tested, and the various test results are as follows:

[0109] 1. Bending test

[0110] A set of three flexural specimens (length × width × thickness 500 mm × 100 mm × 50 mm) were prepared using the material ratio and preparation method of Example 4 of this invention. All specimens were cured at room temperature for 28 days under a plastic film and a damp cotton blanket. The flexural strength of the specimens was tested using a SANS MTS testing machine. Before the test, strain gauges were placed at the bottom test section of the specimen, and the XTXDIC (three-dimensional full-field strain measurement system) was placed at the calculation position directly in front of the specimen. The flexural test was performed on the specimens according to the equipment operation method. The post-test photographs are shown below. Figure 13 .

[0111] The test results show that the average flexural strength of the specimen after 28 days of curing is 13.9 MPa. The "Design Standard for Steel Fiber Reinforced Concrete Structures" requires that the flexural strength of the steel fiber reinforced concrete in the bridge deck pavement layer should not be less than 5.5 MPa. The flexural strength of the specimen of this invention is much higher than the requirement of the "Design Standard for Steel Fiber Reinforced Concrete Structures". Therefore, this invention uses a combination of cast ultra-high performance cement-based composite material layer 3 and cold connection key 2 to form a composite steel bridge deck, which has high flexural strength.

[0112] Example 6

[0113] With 1m 3 Taking hybrid fiber ultra-high performance cement-based composite materials as an example, in 1m 3 The hybrid fiber ultra-high performance cementitious composite material is composed of materials in the following mass ratio:

[0114]

[0115] In the above mass ratio, the cement used is P.O42.5 ordinary Portland cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of the standard sand is less than 0.8mm; the water-reducing agent A component is a 3301c type high-efficiency water-reducing agent; the water-reducing agent B component is microsphere powder, which is used in combination with the water-reducing agent A component; the copolymerized formaldehyde fiber has a length of 12mm, a diameter of 200μm, an elastic modulus of 10GPa, a breaking strength of 7.0~8.5cN / dtex, and a breaking elongation of 13~15%; the steel fiber is copper-plated steel fiber with a length of 13mm and a diameter of 0.2mm.

[0116] Its preparation method is the same as that in Example 4.

[0117] Example 7

[0118] With 1m 3 Taking hybrid fiber ultra-high performance cement-based composite materials as an example, in 1m 3 The hybrid fiber ultra-high performance cementitious composite material is composed of materials in the following mass ratio:

[0119]

[0120]

[0121] In the above mass ratio, the cement is P.O42.5 ordinary Portland cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of the standard sand is less than 0.8mm; the water-reducing agent A component is a 3301c type high-efficiency water-reducing agent; the water-reducing agent B component is microsphere powder, which is used in combination with the water-reducing agent A component; the copolymerized formaldehyde fiber has a length of 12mm, a diameter of 200μm, an elastic modulus of 10GPa, a breaking strength of 7.0~8.5cN / dtex, and a breaking elongation of 13~15%; the steel fiber is copper-plated steel fiber with a length of 13mm and a diameter of 0.2mm.

[0122] Its preparation method is the same as that in Example 4.

Claims

1. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys, characterized in that... The construction steps include the following: S1, Pre-cooling connection key (2); The pre-cooling connection key (2) consists of a stud (2-1) and a casting part (2-2), with the stud (2-1) located inside the casting part (2-2); The casting part is made of ultra-high performance cement-based composite material; The casting part (2-2) contains 1 to 3 bamboo sections, each bamboo section consisting of a cylindrical body and a circumferential protrusion located in the middle of the cylindrical body, the circumferential protrusion being formed by four arc segments a, b, c, and d smoothly connected, the arc formed by the connection of arc segments a and b and the arc formed by the connection of arc segments c and d being symmetrically arranged about the height direction of the cylindrical body, the radius of arc segments a and d being 12 to 16 mm and the central angle being 0.18π to 0.24π, the radius of arc segments b and c being 5 to 8 mm and the central angle being 0.22π to 0.26π, the diameter of the cylindrical body being 80 to 150 mm and the height being 50 to 80 mm; S2. Use a high-pressure air gun to remove dust and clean the top plate of the steel bridge deck (1); S3. Set cold connection keys (2) on the top plate (1) of the steel bridge deck. The longitudinal distance between adjacent cold connection keys (2) is 30-50 cm and the transverse distance is 30-50 cm. S4. Arrange the steel mesh and pour the ultra-high performance cement-based composite material layer (3) on the top plate (1) and cold connection key (2) of the steel bridge deck.

2. The UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 1, characterized in that: The cold connection key (2) is bonded to the top plate (1) of the steel bridge deck by structural adhesive (4).

3. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 2, characterized in that: The structural adhesive (4) has a thickness of 1.5 to 3 mm.

4. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 1, characterized in that: The stud (2-1) has a diameter of 8-16 mm and a height that is the same as that of the cast part (2-2).

5. A UHPFRC composite steel bridge deck using a bamboo-joint type cold-connecting key as described in claim 1, characterized in that: The two adjacent rows of cold connection keys (2) are arranged parallel to each other on the top plate (1) of the steel bridge deck.

6. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 1, characterized in that: The adjacent rows of cold connection keys (2) are arranged in a crisscross pattern on the top plate (1) of the steel bridge deck.

7. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 1, characterized in that: The casting component (2-2) and the stud (2-1) are arranged concentrically.

8. A UHPFRC composite steel bridge deck using a bamboo-joint type cold-connecting key as described in claim 1, characterized in that: The ultra-high performance cement-based composite material is a copolymerized formaldehyde fiber ultra-high performance cement-based composite material, and the 1m 3 The copolymerized formaldehyde fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio: 900-1100 kg of cement 60-75 kg of silica fume 1250–1380 kg of standard sand or river sand Water-reducing agent component A 35-45 kg Water-reducing agent component B 170-180 kg 165-170 kg of water Copolymerized formaldehyde fiber, 28–45 kg; The cement is P.O42.5 silicate cement; the silica fume has a particle size distribution range of 0.1–0.15 μm and a specific surface area of ​​15–27 m². 2 / g; the maximum particle size of standard sand or river sand is less than 0.8 mm; water-reducing agent A is 3301c type high-efficiency water-reducing agent; water-reducing agent B is microsphere powder, which is used in combination with water-reducing agent A; the copolymerized formaldehyde fiber has a length of 12 mm, a diameter of 200 μm, an elastic modulus of 10 GPa, a breaking strength of 7.0~8.5 cN / dtex, and a breaking elongation of 13~15%.

9. A UHPFRC composite steel bridge deck using bamboo-joint cold-connecting keys according to claim 1, characterized in that: The ultra-high performance cement-based composite material is a hybrid fiber ultra-high performance cement-based composite material, and the 1 m 3 The hybrid fiber ultra-high performance cement-based composite material is composed of materials in the following mass ratio: 900-1100 kg of cement 60-75 kg of silica fume 1250–1380 kg of standard sand or river sand Water-reducing agent component A 35-45 kg Water-reducing agent component B 170-180 kg 165-170 kg of water 10-30 kg of polyoxymethylene fiber 75-120 kg of steel fiber The copolymerized polyoxymethylene fibers are 12 mm long, 200 μm in diameter, have an elastic modulus of 10 GPa, a tensile strength of 7.0–8.5 cN / dtex, and an elongation at break of 13%–15%. The steel fibers are copper-plated, 13 mm long, and 0.2 mm in diameter. The silica fume particles range from 0.1 to 0.15 μm in size, with a specific surface area of ​​15–27 m². 2 / g; Water-reducing agent A is 3301c type high-efficiency water-reducing agent; Water-reducing agent B is microsphere powder, which is used in combination with water-reducing agent A; Cement is P.O42.5 ordinary Portland cement; The maximum particle size of standard sand or river sand is less than 0.8mm.

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