Construction process of a cable-stayed bridge deck of a steel-concrete composite beam for reducing cracking

Abstract

This application relates to a construction process for the stay cable bridge deck of a steel-concrete composite beam to reduce cracking. The construction process includes the following steps: S1. Spraying a surface treatment agent on the orthotropic steel surface; S2. Installing the orthotropic steel, cleaning and inspecting the bridge deck; S3. Measuring and setting out; S4. Installing shear studs and tying steel bars; S5. Spraying a surface treatment agent on the steel bars; S6. Spraying hot steam, pouring concrete, and the hot steam spraying shall not exceed 10 minutes before the concrete pouring; S7. Finishing and curing. This application has the effect of reducing the cracking probability of the orthotropic steel-concrete composite bridge deck.

Description

Technical Field

[0001] The present application relates to the field of bridge construction techniques, and particularly to a construction technique for the stay cable bridge deck of a steel-concrete composite beam that reduces cracking. Background Technique

[0002] A stay cable bridge with a steel-concrete composite beam is a type of bridge in which the steel-concrete composite main beam is directly pulled by many stay cables on the bridge tower, and it is a structural system composed of a tower under compression, cables under tension, and a steel-concrete composite beam under bending.

[0003] The bridge deck is the load-bearing structure in a stay cable bridge with a steel-concrete composite beam that directly bears the wheel pressure of vehicles. The bridge deck is usually integrally connected to the beam ribs and diaphragms of the steel-concrete composite beam and is a component of the cross-section of the steel-concrete composite beam. The bridge deck transfers the vehicle load to the steel-concrete composite beam, ensuring the overall effect of the steel-concrete composite beam.

[0004] The bridge deck usually adopts an orthotropic steel-concrete composite structure, but the concrete is prone to dry shrinkage cracking, resulting in the formation of gaps between the concrete and the orthotropic steel, reducing the bond strength between the concrete and the orthotropic steel. When the bridge deck bears the load, there is a tendency for relative movement between the concrete and the orthotropic steel, reducing the stability of the bridge deck and causing the orthotropic steel-concrete composite bridge deck to be prone to cracking. Summary of the Invention

[0005] In order to reduce the probability of cracking of the orthotropic steel-concrete composite bridge deck, the present application provides a construction technique for the stay cable bridge deck of a steel-concrete composite beam that reduces cracking.

[0006] A construction technique for the stay cable bridge deck of a steel-concrete composite beam that reduces cracking provided by the present application adopts the following technical solution: A construction technique for the stay cable bridge deck of a steel-concrete composite beam that reduces cracking includes the following steps:

[0007] S1. Spraying a surface treatment agent on the surface of the orthotropic steel;

[0008] S2. Installing the orthotropic steel, cleaning and inspecting the bridge deck;

[0009] S3. Measuring and lofting;

[0010] S4. Installing shear studs and binding steel bars;

[0011] S5. Spraying a surface treatment agent on the steel bars;

[0012] S6. Spraying hot steam, pouring concrete, and the spraying of hot steam shall not exceed 10 minutes before the concrete pouring;

[0013] S7. Finishing and curing;

[0014] The concrete comprises the following raw materials in parts by weight: 192 - 360 parts of portland cement; 3 - 5 parts of water reducing agent; 140 - 150 parts of mixing water; 64 - 120 parts of powder; 720 - 1100 parts of coarse aggregate; 420 - 790 parts of fine aggregate; 38 - 146 parts of coated steel fiber; 18 - 36 parts of expansion filler;

[0015] The expansion filler comprises an expansion agent and modified bentonite, and the weight ratio of the expansion agent to the modified bentonite is (2 - 8):5; the surface treatment agent comprises ethyl α - cyanoacrylate, a high polymer and neodymium iron boron powder, and the weight ratio of ethyl α - cyanoacrylate, polyacrylate and neodymium iron boron powder is 10:(2 - 6):1.

[0016] By adopting the above technical scheme, the surface treatment agent is coated on the orthotropic steel surface, and the neodymium iron boron powder mixed uniformly with ethyl α - cyanoacrylate and the high polymer is adsorbed on the orthotropic steel surface under the magnetic action, thereby improving the bonding strength between the surface treatment agent and the orthotropic steel; before the concrete pouring, the steam treatment softens the ethyl α - cyanoacrylate and the high polymer on the orthotropic steel surface, and after the concrete pouring, the modified bentonite in the concrete adsorbs with the cyanide organic matter ethyl α - cyanoacrylate, and the modified bentonite bonds with the high polymer, thereby improving the bonding strength between the expansion filler and the orthotropic steel; during the concrete curing period, the expansion agent expands, filling the gap between the concrete and the orthotropic steel, improving the bonding strength between the orthotropic steel and the concrete, meanwhile improving the self - compactness of the concrete, reducing the probability of concrete dry shrinkage cracking, and thus reducing the probability of cracking of the orthotropic steel - concrete composite bridge deck.

[0017] Optionally, the high polymer is polyacrylate.

[0018] By adopting the above technical scheme, the polyacrylate and the modified bentonite form a three - dimensional network structure, thereby improving the bonding strength between the concrete and the orthotropic steel; the polyacrylate forms a waterproof film on the orthotropic steel surface, hindering water molecules from penetrating into the space between the concrete and the orthotropic steel, thereby reducing the probability of peeling between the concrete and the orthotropic steel, and further reducing the probability of cracking of the bridge deck.

[0019] Optionally, the expansion agent comprises lime - fly ash soil, bauxite and gypsum powder, and the weight ratio of the lime - fly ash soil, bauxite and gypsum powder is 4:1:3.

[0020] By adopting the above technical scheme, under the action of hydration heat, calcium oxide in the lime - fly ash soil, aluminum oxide in the fly ash and bauxite, and calcium sulfate in the gypsum powder react to generate calcium sulfoaluminate crystals, and the calcium sulfoaluminate crystals fill the pores in the concrete, thereby reducing the probability of concrete dry shrinkage and making the bridge deck not easy to form early cracks.

[0021] Optionally, the modified bentonite includes calcium-based bentonite and rhamnose, and the weight ratio of the calcium-based bentonite to rhamnose is 4:1.

[0022] By adopting the above technical solution, rhamnose is loaded on the calcium-based bentonite, facilitating the mutual adsorption of the modified bentonite and substances containing metal cations under the action of electric charges; rhamnose forms a cyclic structure complex with metal ions, improving the adsorption strength of the calcium-based bentonite for lime-fly ash soil, bauxite, and gypsum powder, facilitating the calcium-based bentonite to carry the expansion agent to the surface of the orthotropic steel, and forming calcium sulfoaluminate crystals at the interface between the orthotropic steel and the concrete, which are easy to fill the gaps, thereby reducing the probability of mutual peeling between the orthotropic steel and the concrete, and thus reducing the probability of the bridge deck cracking.

[0023] Optionally, the preparation steps of the modified bentonite include: roasting the calcium-based bentonite; heating rhamnose to melting, adding the roasted calcium-based bentonite, stirring evenly, and cooling and drying to form powder to obtain the modified bentonite.

[0024] By adopting the above technical solution, roasting the calcium-based bentonite increases the specific surface area, facilitating the loading of rhamnose; the molten rhamnose adheres to the surface and internal pores of the calcium-based bentonite particles, reducing the probability of separation between rhamnose and the calcium-based bentonite particles during concrete mixing, thereby facilitating the modified bentonite to load lime-fly ash soil, bauxite, and gypsum powder, and at the same time improving the bonding strength between the modified bentonite and the orthotropic steel.

[0025] Optionally, the coated steel fiber includes corrugated steel fiber and a coating liquid, and the coating liquid is coated on the outer surface of the corrugated steel fiber.

[0026] By adopting the above technical solution, compared with straight steel fibers, the contact area between the corrugated steel fibers and cement particles, etc. increases. When the concrete shrinks, the probability of peeling between the corrugated steel fibers and the cement paste decreases, thereby reducing the probability of pores generated in the concrete, and further reducing the probability of the bridge deck cracking.

[0027] Optionally, the coating liquid includes wolframite powder and vinyl silicone oil, and the weight ratio of the wolframite powder to the vinyl silicone oil is (2 - 5):13.

[0028] By adopting the above technical solution, when lime-fly ash soil, bauxite, gypsum powder, and cement particles act, sodium ions are displaced and react with water to easily form alkaline sodium hydroxide. In addition, alkaline substances carried by rainwater, ski agents, etc. penetrate into the concrete, increasing the probability of corrosion of the corrugated steel fibers and the orthotropic steel; the wolframite powder is adhered to the surface of the corrugated steel fibers by the vinyl silicone oil, hindering the erosion of the corrugated steel fibers by alkaline substances, thereby improving the alkali corrosion resistance of the bridge deck and extending the service life of the bridge deck.

[0029] Optionally, the curing method in S6 adopts steam curing.

[0030] By adopting the above technical solution, under the action of hot steam, scheelite powder reacts with sodium hydroxide aqueous solution to generate crude sodium tungstate, reducing the content of free sodium ions in the concrete and reducing the probability of alkali corrosion of the orthotropic steel-concrete structure, thereby improving the corrosion resistance of the bridge deck and reducing the probability of the bridge deck cracking.

[0031] Optionally, during the pouring of S5 concrete, an insertion vibrator is used for layered vibration compaction.

[0032] By adopting the above technical solution, the layered vibration compaction of the vibrator promotes the flow of the concrete, reduces the porosity in the concrete, and increases the density of the concrete, thereby reducing the probability of cracks generated by concrete shrinkage, increasing the compressive strength of the bridge deck, and reducing the probability of the bridge deck cracking.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. The surface treatment agent is coated on the surface of the orthotropic steel, and the neodymium iron boron powder mixed evenly with α-cyanoacrylate and the polymer is adsorbed on the surface of the orthotropic steel under the magnetic action, thereby improving the bonding strength between the surface treatment agent and the orthotropic steel, and further reducing the probability of cracking of the orthotropic steel-concrete composite bridge deck;

[0035] 2. Before the concrete pouring, the steam treatment softens the α-cyanoacrylate and the polymer on the surface of the orthotropic steel. After the concrete is poured, the modified bentonite in the concrete adsorbs with the cyanide organic matter α-cyanoacrylate, and the modified bentonite and the polyacrylate form a three-dimensional network bonding structure, thereby improving the bonding strength between the expansion filler and the orthotropic steel; during the concrete curing, the expansion agent expands and fills the gap between the concrete and the orthotropic steel, improving the bonding strength between the orthotropic steel and the concrete, thereby reducing the probability of cracking of the orthotropic steel-concrete composite bridge deck;

[0036] 3. Under the action of hydration heat, calcium oxide in the lime-fly ash soil, fly ash and aluminum oxide in the bauxite react with calcium sulfate in the gypsum powder to generate calcium sulfoaluminate crystals, and the calcium sulfoaluminate crystals fill the pores in the concrete, thereby reducing the probability of concrete dry shrinkage and making it difficult for the bridge deck to form early cracks;

[0037] 4. Rhamnose is loaded on the calcium-based bentonite, which facilitates the adsorption of the modified bentonite and substances containing metal cations under the action of charge; rhamnose forms a cyclic structure complex with metal ions, improving the adsorption strength of the calcium-based bentonite on the lime-fly ash soil, bauxite and gypsum powder, facilitating the calcium-based bentonite to carry the expansion agent to the surface of the orthotropic steel, and forming calcium sulfoaluminate crystals at the interface between the orthotropic steel and the concrete, thereby reducing the probability of mutual peeling between the orthotropic steel and the concrete, and thus reducing the probability of cracking of the bridge deck;

[0038] 5. When part of the insulating oil comes into contact with ethyl α-cyanoacrylate, it promotes the softening of ethyl α-cyanoacrylate, facilitating the mutual adsorption of ethyl α-cyanoacrylate and the modified bentonite in the concrete, and improving the bonding strength between the concrete and the orthotropic steel. Description of the Drawings

[0039] Figure 1 It is a schematic diagram of the bridge deck structure in the embodiment of the present application;

[0040] Figure 2 It is a schematic diagram of the overall structure of the shear studs in the embodiment of the present application.

[0041] Description of the Reference Numerals:

[0042] 10. Orthotropic steel; 11. Special-shaped steel plate; 12. Panel; 20. Steel bar; 30. Shear stud; 31. Threaded column; 32. Connecting frustum; 33. Top cover; 40. Concrete layer. Detailed Description of the Embodiment

[0043] The following further elaborates on the present application in combination with the examples, comparative examples and attached Figures 1-2 drawings.

[0044] In the following examples, those without specific conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Except as otherwise specified, the raw materials used in the following examples are all commercially available.

[0045] The water reducer is a polycarboxylate water reducer; the powder material is fly ash, with a particle size of 325 mesh and a density of 2.1 kg / m 3 ; the coarse aggregate is crushed stone, with a density of 1500 kg / m 3 , with a specification of 3 - 7 mm; the fine aggregate is river sand, with a particle size of 20 - 40 mesh; the length of the corrugated steel fiber is 10 - 15 mm, and the length-diameter ratio is 60 ± 5; the wolframite powder is obtained by grinding wolframite ore, with a particle size of 400 mesh and the FeWO4 content greater than 80%; the ratio of lime:fly ash:soil in the lime-fly ash-soil is 10:20:70; the bauxite specification is 120 mesh, and the apparent density is 2.6 kg / m 3 ; the density of the gypsum powder is 2.32 kg / m 3 ; the calcium-based bentonite has a particle size of 325 mesh and a density of 2.6 g / cm 3 ; the molecular weight of rhamnose is 164.16, and the content is 99%; the neodymium iron boron powder has a particle size of 400 mesh and is provided by Guangzhou Xinnuode Transmission Parts Co., Ltd.

[0046] Preparation Example of Coated Steel Fibers

[0047] Preparation Example 1

[0048] S1. Mix 20 kg of wolframite powder evenly with 130 kg of vinyl silicone oil to obtain a coating solution;

[0049] S2. Immerse 150 kg of corrugated steel fibers in the coating solution for 30 min, then dry them at 40 °C. After drying and curing, shake and separate them into single fibers to obtain coated steel fibers.

[0050] Preparation Example 2

[0051] S1. Mix 35 kg of wolframite powder evenly with 130 kg of vinyl silicone oil to obtain a coating solution;

[0052] S2. Immerse 150 kg of corrugated steel fibers in the coating solution for 30 min, then dry them at 40 °C. After drying and curing, shake and separate them into single fibers to obtain coated steel fibers.

[0053] Preparation Example 3

[0054] S1. Mix 50 kg of wolframite powder evenly with 130 kg of vinyl silicone oil to obtain a coating solution;

[0055] S2. Immerse 150 kg of corrugated steel fibers in the coating solution for 30 min, then dry them at 40 °C. After drying and curing, shake and separate them into single fibers to obtain coated steel fibers.

[0056] Preparation Example 4

[0057] S1. Take 130 kg of vinyl silicone oil and mix it evenly to obtain a coating solution;

[0058] S2. Immerse 150 kg of corrugated steel fibers in the coating solution for 30 min, then dry them at 40 °C. After drying and curing, shake and separate them into single fibers to obtain coated steel fibers.

[0059] Expansion Filler Preparation Example

[0060] Preparation Example 5

[0061] S1. Mix 4 kg of lime-fly ash soil, 1 kg of bauxite and 3 kg of gypsum powder evenly to obtain an expansion agent;

[0062] S2. Roast 8 kg of calcium-based bentonite; heat 2 kg of rhamnose to melting, add the roasted calcium-based bentonite, stir evenly, cool and dry to make powder to obtain modified bentonite;

[0063] S3. Mix the expansion agent and the modified bentonite evenly to obtain an expansion filler.

[0064] Preparation Example 6

[0065] S1. Mix 6 kg of lime-fly ash soil, 1.5 kg of bauxite and 4.5 kg of gypsum powder evenly to obtain an expansion agent;

[0066] S2. Calcine 12 kg of calcium-based bentonite; heat 3 kg of rhamnose to melting, add the calcined calcium-based bentonite, stir evenly, cool, dry and powder to obtain modified bentonite;

[0067] S3. Mix the swelling agent and the modified bentonite evenly as the swelling filler.

[0068] Preparation Example 7

[0069] S1. Mix 8 kg of lime-fly ash soil, 2 kg of bauxite and 6 kg of gypsum powder evenly as the swelling agent;

[0070] S2. Calcine 16 kg of calcium-based bentonite; heat 4 kg of rhamnose to melting, add the calcined calcium-based bentonite, stir evenly, cool, dry and powder to obtain modified bentonite;

[0071] S3. Mix the swelling agent and the modified bentonite evenly as the swelling filler.

[0072] Preparation Example 8

[0073] The difference from Preparation Example 5 is that in S2, 12 kg of calcium-based bentonite and 3 kg of rhamnose are added.

[0074] Preparation Example 9

[0075] The difference from Preparation Example 5 is that in S2, 16 kg of calcium-based bentonite and 4 kg of rhamnose are added.

[0076] Preparation Example 10.

[0077] The difference from Preparation Example 6 is that in S2, 8 kg of calcium-based bentonite and 2 kg of rhamnose are added.

[0078] Preparation Example 11

[0079] The difference from Preparation Example 6 is that in S2, 16 kg of calcium-based bentonite and 4 kg of rhamnose are added.

[0080] Preparation Example 12

[0081] The difference from Preparation Example 7 is that in S2, 8 kg of calcium-based bentonite and 2 kg of rhamnose are added.

[0082] Preparation Example 13

[0083] The difference from Preparation Example 7 is that in S2, 12 kg of calcium-based bentonite and 3 kg of rhamnose are added.

[0084] Table 1 Raw material table of Preparation Examples 5 to 13 (kg)

[0085]

[0086] Surface treatment agent preparation example

[0087] Preparation Example 14

[0088] 4 kg of molten polyacrylate was mixed evenly with 1.5 kg of neodymium iron boron powder to serve as a surface treatment agent.

[0089] Preparation Example 15

[0090] 15 kg of molten ethyl α-cyanoacrylate and 1.5 kg of neodymium iron boron powder were mixed evenly to serve as a surface treatment agent.

[0091] Preparation Example 16

[0092] 15 kg of molten ethyl α-cyanoacrylate and 4 kg of molten polyacrylate were mixed evenly to serve as a surface treatment agent.

[0093] Preparation Example 17

[0094] 10 kg of molten ethyl α-cyanoacrylate, 2 kg of molten polyacrylate and 1 kg of neodymium iron boron powder were mixed evenly to serve as a surface treatment agent.

[0095] Preparation Example 18

[0096] The difference from Preparation Example 17 is that 4 kg of molten polyacrylate was added.

[0097] Preparation Example 19

[0098] The difference from Preparation Example 17 is that 6 kg of molten polyacrylate was added.

[0099] Preparation Example 20

[0100] 15 kg of molten ethyl α-cyanoacrylate, 2 kg of molten polyacrylate and 1.5 kg of neodymium iron boron powder were mixed evenly to serve as a surface treatment agent.

[0101] Preparation Example 21

[0102] The difference from Preparation Example 20 is that 4 kg of molten polyacrylate was added.

[0103] Preparation Example 22

[0104] The difference from Preparation Example 21 is that 6 kg of molten polyacrylate was added.

[0105] Preparation Example 23

[0106] 20 kg of molten ethyl α-cyanoacrylate, 2 kg of molten polyacrylate and 2 kg of neodymium iron boron powder were mixed evenly to serve as a surface treatment agent.

[0107] Preparation Example 24

[0108] The difference from Preparation Example 23 is that 4 kg of molten polyacrylate is added.

[0109] Preparation Example 25

[0110] The difference from Preparation Example 23 is that 6 kg of molten polyacrylate is added.

[0111] Table 2 Raw material table of Preparation Examples 14 - 25 (kg)

[0112]

[0113]

[0114] Examples

[0115] Example 1

[0116] S1. Stir 192 kg of portland cement, 3 kg of water reducer, 112 kg of mixing water, 64 kg of powder and the expansive filler prepared in Preparation Example 5 evenly to obtain a primary mixture;

[0117] S2. Mix 720 kg of coarse aggregate, 420 kg of fine aggregate and 28 kg of mixing water evenly to obtain a coarse mixture;

[0118] S3. Mix the primary mixture and the coarse mixture evenly to obtain a pre - mixture;

[0119] S4. Add 35 kg of the coated steel fibers prepared in Preparation Example 1 to the pre - mixture and stir evenly to obtain concrete.

[0120] Example 2

[0121] S1. Stir 276 kg of portland cement, 4 kg of water reducer, 116 kg of mixing water, 92 kg of powder and the expansive filler prepared in Preparation Example 6 evenly to obtain a primary mixture;

[0122] S2. Mix 910 kg of coarse aggregate, 605 kg of fine aggregate and 29 kg of mixing water evenly to obtain a coarse mixture;

[0123] S3. Mix the primary mixture and the coarse mixture evenly to obtain a pre - mixture;

[0124] S4. Add 92 kg of the coated steel fibers prepared in Preparation Example 2 to the pre - mixture and stir evenly to obtain concrete.

[0125] Example 3

[0126] S1. Stir 360 kg of portland cement, 5 kg of water reducer, 120 kg of mixing water, 120 kg of powder and the expansive filler prepared in Preparation Example 7 evenly to obtain a primary mixture;

[0127] S2. Mix 1100 kg of coarse aggregate, 790 kg of fine aggregate and 30 kg of mixing water evenly to obtain a coarse mixture.

[0128] S3. Mix the preliminary mixture and the coarse mixture evenly to obtain a pre - mixture.

[0129] S4. Add 146 kg of the coated steel fibers prepared in Preparation Example 1 to the pre - mixture and stir evenly to obtain concrete.

[0130] Example 4

[0131] The difference from Example 2 is: adding 92 kg of the coated steel fibers prepared in Preparation Example 4.

[0132] Example 5

[0133] The difference from Example 2 is: adding 92 kg of the coated steel fibers prepared in Preparation Example 1.

[0134] Example 6

[0135] The difference from Example 2 is: adding 92 kg of the coated steel fibers prepared in Preparation Example 3.

[0136] Example 7

[0137] The difference from Example 2 is: using the expansion filler prepared in Preparation Example 5.

[0138] Examples 8 - 14

[0139] The difference from Example 2 is: successively using the expansion fillers prepared in Preparation Examples 7 - 13.

[0140] Example 15

[0141] Refer to Figure 1 , a bridge deck structure, including orthotropic steel 10, a steel bar layer and a concrete layer 40. The orthotropic steel 10 includes a profiled steel plate 11 and a panel 12. The upper surface of the panel 12 is rectangular. The profiled steel plate 11 is a U - shaped plate. The profiled steel plate 11 is arranged parallel to the length direction of the upper surface of the panel 12. Multiple profiled steel plates 11 are arranged in sequence along the width direction of the upper surface of the panel 12, and the top wall of the profiled steel plate 11 is fixedly welded to the bottom wall of the panel 12. The steel bar layer includes transverse bars and longitudinal bars. The transverse bars are arranged parallel to the width direction of the upper surface of the panel 12, and the longitudinal bars are arranged parallel to the length direction of the upper surface of the panel 12. Multiple transverse bars and longitudinal bars are tied to form a steel bar layer. The steel bars 20 of the steel bar layer are fixedly connected to the top wall of the panel 12. The concrete layer 40 is located above the panel 12, and the concrete layer 40 passes through the steel bar layer and is fixedly bonded to the top wall of the panel 12. The steel bar layer is wrapped in the concrete layer 40.

[0142] Refer to Figure 1 and Figure 2, to increase the connection strength between the orthotropic steel 10 and the concrete layer 40, a plurality of shear studs 30 are provided on the panel 12. The shear stud 30 includes a threaded column 31, a connecting frustum 32, and a top cover 33. The threaded column 31 is perpendicularly arranged with respect to the top wall of the panel 12, and the threaded column 31 is fixedly connected to the top wall of the panel 12 by threading. The connecting frustum 32 is coaxially arranged with the threaded column 31, and the end wall of the large end of the connecting frustum 32 is fixedly connected to the top wall of the threaded column 31. The end wall of the large end of the connecting frustum 32 abuts against the top wall of the panel 12. The top cover 33 is a cylinder coaxially arranged with the connecting frustum 32, and the bottom wall of the top cover 33 is fixedly connected to the end wall of the small end of the connecting frustum 32. An obtuse angle is formed between the shear stud 30 and the top wall of the panel 12, which is convenient for concrete filling and reduces the pore volume in the concrete.

[0143] The implementation principle of Example 15 is as follows:

[0144] Bind the transverse bars and longitudinal bars to form a steel bar layer, fix the steel bar layer on the panel 12 of the orthotropic steel 10, thread-connect a plurality of shear studs 30 to the panel 12 of the orthotropic steel 10, pour concrete, and the concrete passes through the steel bar layer and is adhesively fixed to the panel 12 of the orthotropic steel 10 to form a bridge deck structure.

[0145] Example 16

[0146] S1. Uniformly spray the surface treatment agent prepared in Preparation Example 14 on the surface of the orthotropic steel 10;

[0147] S2. Install the orthotropic steel 10 on the cable-stayed bridge, and clean and accept the bridge deck;

[0148] S3. Measure and set out on the bridge deck, and draw the installation positions of the shear studs 30;

[0149] S4. According to the marked point positions measured and set out, install the shear studs 30 on the orthotropic steel 10, bind the steel bars 20 to form a steel bar layer, and fixedly connect them to the orthotropic steel;

[0150] S5. Spray the surface treatment agent prepared in Preparation Example 14 on the steel bars 20;

[0151] S6. Spray hot steam on the steel bars 20 and the orthotropic steel 10 to soften the surfactants on the orthotropic steel 10 and the steel bars 20, and then pour the concrete prepared in Example 2. The hot steam spraying shall not exceed 10 minutes before the concrete pouring. During the concrete pouring process, use an inserted vibrator to vibrate in layers. The vibrator is inserted quickly and pulled out slowly to reduce the pore volume in the concrete;

[0152] S7. Manually level the upper surface of the concrete, and use the steam curing method to cure the concrete until it forms a concrete shape to form a bridge deck.

[0153] Examples 17 to 27

[0154] The difference from Example 16 is that surfactants prepared from Preparation Examples 15 to 25 are used in sequence.

[0155] Example 28

[0156] The difference from Example 16 is that 5 kg of insulating oil is added to the concrete prepared in Example 2.

[0157] Comparative Example

[0158] Comparative Example 1

[0159] The difference between this comparative example and Example 2 is that coated steel fibers are not added, and 92 kg of corrugated steel fibers are added.

[0160] Comparative Example 2

[0161] The difference between this comparative example and Example 2 is that expansive filler is not added.

[0162] Comparative Example 3

[0163] The difference between this comparative example and Example 2 is that modified bentonite is not added.

[0164] Comparative Example 4

[0165] The difference between this comparative example and Example 15 is that surfactants are not sprayed on orthotropic steel and steel bars.

[0166] Table 3 Raw material table (kg) of Examples 1 to 14 and Comparative Examples 1 to 3

[0167]

[0168]

[0169] Performance detection test

[0170] Test method

[0171] 1. The compressive strength (MPa) of the concrete is measured by the method in "Standard Test Method for Mechanical Properties of Ordinary Concrete" (GB / T50081 - 2002). The test results are shown in Table 4.

[0172] 2. The flexural strength (MPa) of the concrete is measured by the method in "Standard Test Method for Mechanical Properties of Ordinary Concrete" (GB / T50081 - 2002). The test results are shown in Table 4.

[0173] 4. The shrinkage rate (%) of the concrete was measured by the method in "Standard Test Method for Long-Term Performance and Durability of Ordinary Concrete (GB / T 50082 - 2009)". The test results are shown in Table 4.

[0174] 5. The direct tensile bond strength (MPa) between the concrete and orthotropic steel was measured by the method in "Code for Acceptance of Construction Quality of Building Structure Strengthening Engineering (GB50550 - 2010)". The test results are shown in Table 5.

[0175] Table 4 Data Sheet of Test Results for Examples 1 - 14 and Comparative Examples 1 - 3

[0176]

[0177]

[0178] Combined with Examples 1, 2, and 3 and Table 4, by adjusting the types and addition amounts of portland cement, water reducer, mixing water, powder, coarse aggregate, fine aggregate, coated steel fiber, and expansion filler, the compressive strength and flexural strength of the concrete were increased, and the shrinkage rate of the concrete was reduced.

[0179] Combined with Example 2 and Comparative Example 1 and Table 4, it can be seen that compared with the addition of corrugated steel fiber, the addition of coated steel fiber increased the compressive strength and flexural strength of the concrete and reduced the shrinkage rate of the concrete. The coated steel fiber includes corrugated steel fiber and a coating liquid coated on the surface of the corrugated steel fiber. The coating liquid is composed of vinyl silicone oil and wolframite powder. The wolframite powder is adhered to the surface of the corrugated steel fiber by the vinyl silicone oil, forming a flexible coating on the surface of the corrugated steel fiber, making the corrugated steel fiber not easily broken, thereby increasing the compressive strength and flexural strength of the concrete. The shrinkage rate of the coated steel fiber is lower than that of the concrete. During the evaporation of water in the concrete, the coated steel fibers adhere to and support the cement particles and aggregates, making the concrete not easily shrink, thereby reducing the shrinkage rate of the concrete.

[0180] Combining Example 2 and Example 4 and referring to Table 4, it can be seen that the addition of wolframite powder increases the flexural strength of the concrete and reduces the shrinkage rate of the concrete. Tungsten in the wolframite powder reacts with the sodium hydroxide solution in the concrete to form sodium tungstate, reducing the content of free sodium ions in the concrete and decreasing the probability of the concrete being corroded by alkali, thereby increasing the flexural strength of the concrete. Iron ions in the wolframite powder react with air and water molecules to form a dense film, blocking moisture from the coated steel fibers, reducing the probability of corrosion of the coated steel fibers, and increasing the compressive strength and flexural strength of the concrete. Metal cations in the wolframite powder adsorb the modified bentonite in the expansion filler, thereby increasing the bonding strength between the corrugated steel fibers and the expansive agent. When the concrete expands, the expansive agent fills the pores in the expansive agent, improving the self-compacting property of the concrete, making the concrete less prone to drying shrinkage, and thus reducing the shrinkage rate of the concrete.

[0181] Combining Example 2, Example 5 and Example 6 and referring to Table 4, it can be seen that as the weight ratio of wolframite powder to vinyl silicone oil increases, both the compressive strength and flexural strength of the concrete first increase and then decrease, and the shrinkage rate of the concrete first decreases and then increases. The reason for the decrease in the compressive strength of the concrete is that the addition of wolframite powder reduces the bonding strength between the coating liquid and the corrugated steel fibers. During the mixing of the concrete, the coating layer on the surface of the corrugated steel fibers is easily peeled off, and the buffering effect of the coating layer on the corrugated steel fibers is reduced, resulting in the easy fracture of the coated steel fibers and the decrease in the compressive strength of the concrete.

[0182] Combining Example 2 and Comparative Example 2 and referring to Table 4, it can be seen that the addition of the expansion filler increases the flexural strength of the concrete and reduces the shrinkage rate of the concrete. The expansion filler includes an expansive agent and modified bentonite. The expansive agent includes lime-fly ash soil, bauxite and gypsum powder, and the modified bentonite includes calcium-based bentonite and rhamnose. Rhamnose adheres to the surface and pores of the calcium-based bentonite. Rhamnose acts as an anionic surfactant, and there are metal cations in the lime-fly ash soil, bauxite and gypsum powder, thereby increasing the connection strength between the lime-fly ash soil, bauxite and gypsum powder and the calcium-based bentonite. Under the action of hydration heat, calcium oxide and fly ash in the lime-fly ash soil react with aluminum oxide in the bauxite and calcium sulfate in the gypsum powder to form calcium sulfoaluminate crystals. The calcium sulfoaluminate crystals fill the pores in the concrete, improving the self-compacting property of the concrete, thereby reducing the probability of drying shrinkage of the concrete, decreasing the shrinkage rate of the concrete, and further increasing the compressive strength and flexural strength of the concrete.

[0183] Combined with Example 2, Comparative Example 2 and Comparative Example 3 and in combination with the surface, it can be seen that the addition of modified bentonite in the expansion filler improves the flexural strength and compressive strength of the concrete and reduces the shrinkage rate of the concrete. The modified bentonite is loaded with lime-fly ash soil, alumstone and gypsum powder, which facilitates the reaction of the three under the action of hydration heat and moisture; the rhamnose in the modified bentonite and the metal ions on the surface of the coated steel fiber adsorb each other, improving the bonding strength between the expansion filler and the coated steel fiber. The expansive agent generates calcium sulfoaluminate crystals, which tightly wrap the coated steel fiber, reducing the probability of forming gaps between the slurry and the coated steel fiber due to concrete shrinkage, thereby reducing the pore volume in the concrete, reducing the shrinkage rate of the concrete, and improving the flexural strength and compressive strength of the concrete.

[0184] Combined with Example 2, Example 7 to Example 14 and in combination with Table 4, by adjusting the ratio of the expansive agent to the modified bentonite, the flexural strength and compressive strength of the concrete are improved, and the shrinkage rate of the concrete is reduced.

[0185] Combined with Example 2, Example 11 and Example 12 and in combination with Table 4, it can be seen that when the addition amount of the expansive agent remains unchanged, increasing the addition amount of the modified bentonite, the compressive strength and flexural strength of the concrete both increase first and then decrease, and the shrinkage rate of the concrete decreases first and then increases. The modified bentonite includes calcium-based bentonite and rhamnose. Rhamnose improves the adsorption efficiency and adsorption amount of calcium-based bentonite to the expansive agent. Calcium-based bentonite binds the expansive agent together, improving the expansion efficiency of the expansive agent, thereby improving the self-compactness of the concrete, increasing the compressive strength and flexural strength of the concrete, and reducing the shrinkage rate. However, the specific surface area of calcium-based bentonite is relatively large. As the addition amounts of calcium-based bentonite and rhamnose increase, part of the expansive agent enters the voids of calcium-based bentonite, and calcium-based bentonite hinders the contact between the expansive agent and water, thus reducing the expansion efficiency of the expansive agent, decreasing the compressive strength and flexural strength of the concrete, and increasing the shrinkage rate.

[0186] Combined with Example 2, Example 9 and Example 14, and in combination with Table 4, it can be seen that when the addition amount of modified bentonite remains unchanged, increasing the addition amount of the expansion agent, the compressive strength and flexural strength of the concrete both increase first and then decrease, and the shrinkage rate of the concrete decreases first and then increases. The expansion agent includes lime-fly ash soil, bauxite and gypsum powder. Under the action of hydration heat, calcium oxide and fly ash in the lime-fly ash soil react with aluminum oxide in the bauxite and calcium sulfate in the gypsum powder to generate calcium sulfoaluminate crystals. The calcium sulfoaluminate crystals fill the pores in the concrete, thereby reducing the shrinkage rate of the concrete. It is not easy for the concrete to form early cracks, and the compressive strength and flexural strength of the concrete are improved. As the addition amounts of lime-fly ash soil, bauxite and gypsum powder increase, the modified bentonite can only load part of the lime-fly ash soil, bauxite and gypsum powder, and the other lime-fly ash soil, bauxite and gypsum powder are separated from the modified bentonite. The lime-fly ash soil, bauxite and gypsum powder are dispersed in the concrete, resulting in that during the curing period of the concrete, it is not easy for the lime-fly ash soil, bauxite and gypsum powder to come into contact and react, reducing the expansion efficiency of the expansion agent, and the compressive strength and flexural strength of the concrete decrease, and the shrinkage rate increases.

[0187] Table 5 Test result data table of Examples 16 to 28 and Comparative Example 4

[0188]

[0189] Combined with Example 23 and Comparative Example 4 and in combination with Table 5, it can be seen that the addition of the surfactant improves the bonding strength between the concrete and the orthotropic steel. The surfactant includes ethyl α-cyanoacrylate, polyacrylate and NdFeB powder. The surface treatment agent is coated on the surface of the orthotropic steel, and the NdFeB powder mixed uniformly with ethyl α-cyanoacrylate and polyacrylate is adsorbed on the surface of the orthotropic steel under the magnetic action, thereby improving the bonding strength between the surface treatment agent and the orthotropic steel.

[0190] Combined with Example 16 and Example 23 and in combination with Table 5, it can be seen that the addition of ethyl α-cyanoacrylate improves the direct tensile bonding strength between the concrete and the orthotropic steel. The modified bentonite in the concrete adsorbs with the cyanide organic matter ethyl α-cyanoacrylate, and the modified bentonite is bonded with the polymer, thereby improving the bonding strength between the concrete and the orthotropic steel.

[0191] Combined with Example 17 and Example 23 and in combination with Table 5, it can be seen that the addition of polyacrylate improves the direct tensile bonding strength between the concrete and the orthotropic steel. The polyacrylate and the modified bentonite form a three-dimensional network structure, thereby improving the bonding strength between the concrete and the orthotropic steel; the polyacrylate forms a waterproof film on the surface of the orthotropic steel, hindering water molecules from penetrating between the concrete and the orthotropic steel, thereby reducing the probability of peeling between the concrete and the orthotropic steel, and thus improving the bonding strength between the concrete and the orthotropic steel.

[0192] Combined with Example 18 and Example 23 and in conjunction with Table 5, it can be seen that the addition of neodymium iron boron powder improves the direct tensile bond strength between the concrete and the orthotropic steel. Under the magnetic action, neodymium iron boron is adsorbed on the surface of the orthotropic steel, thereby improving the bond strength between the surface treatment agent and the orthotropic steel. The rhamnose in the modified bentonite forms a cyclic structure complex with metal ions, improving the adsorption strength of calcium-based bentonite to lime-fly ash soil, bauxite and gypsum powder, facilitating the calcium-based bentonite to carry the expansion agent to the surface of the orthotropic steel, and forming calcium sulfoaluminate crystals at the interface between the orthotropic steel and the concrete, thereby reducing the probability of mutual peeling between the orthotropic steel and the concrete and improving the bond strength between the concrete and the orthotropic steel.

[0193] Combined with Examples 19 to 27 and in conjunction with Table 5, by adjusting the addition amounts of ethyl α-cyanoacrylate, polyacrylate and neodymium iron boron powder, the bond strength between the concrete and the orthotropic steel is improved.

[0194] Combined with Example 22, Example 23 and Example 24 and in conjunction with Table 5, it can be seen that when the addition amounts of ethyl α-cyanoacrylate and neodymium iron boron powder remain unchanged, increasing the addition amount of polyacrylate, the direct tensile bond strength between the concrete and the orthotropic steel first increases and then decreases. The reason for the decrease in the direct tensile bond strength is that the water-repellent film formed by polyacrylate hinders the contact between ethyl α-cyanoacrylate and the orthotropic steel, thereby reducing the bond strength between the surface treatment agent and the orthotropic steel, and further reducing the bond strength between the concrete and the orthotropic steel.

[0195] Combined with Example 20, Example 23 and Example 26 and in conjunction with Table 5, it can be seen that when the addition amount of polyacrylate remains unchanged, increasing the addition amounts of ethyl α-cyanoacrylate and neodymium iron boron powder, the direct tensile bond strength between the concrete and the orthotropic steel first increases and then decreases. The reason for the decrease in the direct tensile bond strength is that the content of polyacrylate in the surface treatment agent decreases, and the bond between polyacrylate and the modified bentonite in the concrete is hindered, resulting in a decrease in the bond strength between the concrete and the orthotropic steel.

[0196] Combined with Example 23 and Example 28 and in conjunction with Table 5, it can be seen that the addition of insulating oil improves the direct tensile bond strength between the concrete and the orthotropic steel. Part of the insulating oil contacts with ethyl α-cyanoacrylate, promoting the softening of ethyl α-cyanoacrylate, facilitating the mutual adsorption between ethyl α-cyanoacrylate and the modified bentonite in the concrete, and improving the bond strength between the concrete and the orthotropic steel.

[0197] This specific embodiment is only an interpretation of the present application and is not a limitation thereto. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A construction process for the stay-cable bridge deck of a steel-concrete composite beam to reduce cracking, characterized in that, It includes the following steps: S1. Spraying a surface treatment agent on the surface of orthotropic steel (10); S2. Installing the orthotropic steel (10), cleaning and inspecting the bridge deck; S3. Measuring and lofting; S4. Installing shear studs (30) and binding steel bars (20); S5. Spraying a surface treatment agent on the steel bars (20); S6. Spraying hot steam, pouring concrete, and the hot steam spraying shall not exceed 10 minutes before the concrete pouring; S7. Finishing and curing; The concrete comprises the following raw materials in parts by weight: 192 - 360 parts of portland cement; 3 - 5 parts of water reducing agent; 140 - 150 parts of mixing water; 64 - 120 parts of powder; 720 - 1100 parts of coarse aggregate; 420 - 790 parts of fine aggregate; 38 - 146 parts of coated steel fiber; 18 - 36 parts of expansion filler; The expansion filler includes an expansion agent and modified bentonite, and the weight ratio of the expansion agent to the modified bentonite is (2 - 8):5; The surface treatment agent includes ethyl α - cyanoacrylate, a high polymer, and neodymium iron boron powder. The high polymer is polyacrylate, and the weight ratio of ethyl α - cyanoacrylate, polyacrylate, and neodymium iron boron powder is 10:(2 - 6):

1.

2. A construction process for a stay-cable bridge deck of a steel-concrete composite beam for reducing cracking according to claim 1, characterized in that, The expansion agent includes lime - fly - soil, bauxite, and gypsum powder, and the weight ratio of lime - fly - soil, bauxite, and gypsum powder is 4:1:

3.

3. A construction process for the stay cable bridge deck of a steel-concrete composite beam for reducing cracking according to claim 2, characterized in that, The modified bentonite includes calcium - based bentonite and rhamnose, and the weight ratio of calcium - based bentonite to rhamnose is 4:

1.

4. A construction process for a stay cable bridge deck of a steel-concrete composite beam for reducing cracking according to claim 3, characterized in that, The preparation steps of the modified bentonite include: roasting calcium - based bentonite; heating rhamnose to melting, adding the roasted calcium - based bentonite, stirring evenly, cooling, drying, and pulverizing to obtain the modified bentonite.

5. A construction process for the stay cable bridge deck of a steel-concrete composite beam for reducing cracking according to claim 3, characterized in that, The coated steel fiber includes corrugated steel fiber and a coating liquid, and the coating liquid is coated on the outer surface of the corrugated steel fiber.

6. A construction process for a cable-stayed bridge deck of a steel-concrete composite beam for reducing cracking according to claim 5, characterized in that The coating liquid includes wolframite powder and vinyl silicone oil, and the weight ratio of wolframite powder to vinyl silicone oil is (2 - 5):

13.

7. A construction process for a stay cable bridge deck of a steel-concrete composite beam for reducing cracking according to claim 1, characterized in that The curing method in S7 adopts steam curing.

8. A construction process for a cable-stayed bridge deck of a steel-concrete composite beam for reducing cracking according to claim 1, characterized in that During the concrete pouring in S6, an internal vibrator is used for vibrating in layers.

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