CN115217036A - Construction process for cable-stayed bridge panel of steel-concrete composite beam capable of reducing cracking - Google Patents

Abstract

The application relates to a construction process for a steel-concrete composite beam cable-stayed bridge panel capable of reducing cracking, which comprises the following steps: s1, spraying a surface treating agent on the surface of orthotropic steel; s2, mounting orthotropic steel, and cleaning and checking and accepting the bridge deck; s3, measuring and lofting; s4, installing shear nails and binding steel bars; s5, spraying a surface treating agent on the steel bar; s6, spraying hot steam, and pouring concrete, wherein the spraying of the hot steam is not more than 10min before the pouring of the concrete; s7, dough collection and maintenance. The method has the effect of reducing the cracking probability of the orthotropic steel-concrete combined bridge deck.

Description

A construction technology of steel-concrete composite beam cable-stayed bridge deck with reduced cracking

technical field

The present application relates to the field of bridge construction techniques, in particular to a construction technique for a steel-concrete composite beam cable-stayed bridge deck that reduces cracking.

Background technique

The steel-concrete composite beam cable-stayed bridge is a kind of bridge in which the steel-concrete composite main girder is directly pulled on the bridge tower with many cables. a structural system.

The bridge deck is the load-bearing structure of the steel-concrete composite beam cable-stayed bridge that directly bears the wheel pressure of the vehicle. The bridge deck is usually integrally connected with the beam rib and diaphragm of the steel-concrete composite beam, and is an integral part of the steel-concrete composite beam section. The bridge deck transmits the vehicle load to the steel-concrete composite beam, ensuring the overall function of the steel-concrete composite beam.

The bridge deck usually adopts an orthotropic steel-concrete composite structure, but the concrete is prone to shrinkage and cracking, resulting in a gap between the concrete and the orthotropic steel, which reduces the bond strength between the concrete and the orthotropic steel, and the bridge deck bears the load. There is a relative movement trend between the concrete and the orthotropic steel, which reduces the stability of the bridge deck and causes the orthotropic steel-concrete composite bridge deck to crack easily.

SUMMARY OF THE INVENTION

In order to reduce the probability of cracking of an orthotropic steel-concrete composite bridge deck, the present application provides a construction process for a steel-concrete composite beam cable-stayed bridge deck that reduces cracking.

The construction technology of a steel-concrete composite girder cable-stayed bridge deck with reduced cracking provided by the application adopts the following technical scheme: a construction technology of a steel-concrete composite girder cable-stayed bridge deck with reduced cracking includes the following steps:

S1. Surface treatment agent is sprayed on the surface of orthotropic steel;

S2, orthotropic steel installation, bridge deck cleaning and acceptance;

S3. Measure and stake out;

S4, shear nail installation, steel bar binding;

S5. Rebar spraying surface treatment agent;

S6. Hot steam spraying, concrete pouring, hot steam spraying shall not exceed 10min before concrete pouring;

S7, surface collection and maintenance;

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 aggregates; 38-146 parts of coated steel fibers; 18-36 parts of expanded fillers;

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 α-cyanoacrylate, high polymer and NdFeB powder, the weight ratio of the α-cyanoacrylate, polyacrylate and NdFeB powder is 10:(2-6):1.

By adopting the above technical scheme, the surface treatment agent is coated on the surface of the orthotropic steel, and the NdFeB powder evenly mixed with α-ethyl cyanoacrylate and high polymer is adsorbed on the surface of the orthotropic steel under the magnetic action, Thus, the bonding strength between the surface treatment agent and the orthotropic steel is improved; before the concrete is poured, the steam treatment softens the α-ethyl cyanoacrylate and polymer on the surface of the orthotropic steel. Bentonite and cyanide organic α-ethyl cyanoacrylate are adsorbed to each other, and the modified bentonite is bonded to the polymer, thereby improving the bonding strength of the expansion filler and the orthotropic steel; during the curing of the concrete, the expansion agent occurs. Expansion, filling the gap between concrete and orthotropic steel, improving the bonding strength of orthotropic steel and concrete, improving the self-compactness of concrete, reducing the probability of drying shrinkage cracking of concrete, thereby reducing the positive Probability of cracking in the deck of a composite steel-concrete composite bridge.

Optionally, the high polymer is polyacrylate.

By adopting the above technical solution, polyacrylate and modified bentonite form a three-dimensional network structure, thereby improving the bonding strength between concrete and orthotropic steel; polyacrylate forms a waterproof film on the surface of orthotropic steel, preventing water The molecules penetrate between the concrete and the orthotropic steel, thereby reducing the probability of peeling off the concrete and the orthotropic steel, thereby reducing the probability of cracking of the bridge deck.

Optionally, the expansion agent includes di-lime, bauxite and gypsum powder, and the weight ratio of the di-lime soil, bauxite and gypsum powder is 4:1:3.

By adopting the above technical scheme, under the action of the heat of hydration, calcium oxide in the lime soil, fly ash, aluminum oxide in the bauxite and calcium sulfate in the gypsum powder react to form calcium sulfoaluminate crystals, and sulfoaluminate Calcium crystals fill the pores in the concrete, thereby reducing the probability of concrete shrinkage, making it difficult for the bridge deck to form early cracks.

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

By adopting the above technical solution, the rhamnose is loaded on the calcium-based bentonite, which facilitates the mutual adsorption of the modified bentonite and the metal cation-containing substance under the action of electric charge; the rhamnose and the metal ion form a cyclic structure complex, which increases the calcium The adsorption strength of base bentonite to dilime, bauxite and gypsum powder is convenient for calcium base bentonite to carry expansion agent to the surface of orthotropic steel, and calcium sulfoaluminate crystals are formed at the interface of orthotropic steel and concrete to easily fill the gap, thereby reducing the problem. The probability of orthotropic steel and concrete peeling off each other is reduced, thereby reducing the probability of bridge deck cracking.

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

By adopting the above technical solution, the calcium-based bentonite roasting increases the specific surface area, which is convenient for loading rhamnose; the molten rhamnose adheres to the surface and internal pores of the calcium-based bentonite particles, reducing the amount of rhamnose and rhamnose during concrete mixing. The probability of separation of calcium-based bentonite particles is convenient for the modified bentonite to be loaded with di-lime, bauxite and gypsum powder, and at the same time, the bonding strength of the modified bentonite and orthotropic steel is improved.

Optionally, the coated steel fibers include corrugated steel fibers and a coating liquid, and the coating liquid is coated on the outer surface of the corrugated steel fibers.

By adopting the above technical solution, compared with the straight steel fiber, the contact area between the corrugated steel fiber and the cement particles is increased, and the probability of the corrugated steel fiber and the cement slurry peeling off when the concrete shrinks is reduced, thereby reducing the generation of the concrete. The probability of porosity, thereby reducing the probability of bridge deck cracking.

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

By adopting the above technical solution, when the limestone, bauxite, gypsum powder and cement particles act, the sodium ions are replaced and the water reacts to easily form alkaline sodium hydroxide. Increases the probability of corrugated steel fibers and orthotropic steel being corroded; wolframite powder is adhered to the surface of corrugated steel fibers by vinyl silicone oil, preventing alkaline substances from eroding corrugated steel fibers, thereby improving the alkali corrosion resistance of bridge decks , extending the service life of the bridge deck.

Optionally, the curing method in S6 adopts steam curing.

By adopting the above technical scheme, under the action of hot steam, wolframite powder reacts with sodium hydroxide aqueous solution to generate crude sodium tungstate, which reduces the content of free sodium ions in concrete and reduces the corrosion of orthotropic steel-concrete structure by alkali. Therefore, the corrosion resistance of the bridge deck is improved, and the probability of cracking of the bridge deck is reduced.

Optionally, insert vibrating rods are used to vibrate in layers during the concrete pouring process of S5.

By adopting the above technical scheme, the vibrating rods vibrate in layers to promote the flow of concrete, reduce the porosity in the concrete, increase the density of the concrete, thereby reducing the probability of cracks caused by the shrinkage of the concrete, and the compressive strength of the bridge deck is improved. The probability of bridge deck cracking is reduced.

To sum up, the present application includes at least one of the following beneficial technical effects:

1. Coat the surface treatment agent on the surface of the orthotropic steel, and the NdFeB powder evenly mixed with α-cyanoacrylate and high polymer is adsorbed on the surface of the orthotropic steel under the magnetic action, thereby improving the surface quality. The bonding strength between the treatment agent and the orthotropic steel, thereby reducing the probability of cracking of the orthotropic steel-concrete composite deck;

2. Before the concrete is poured, steam treatment softens the α-ethyl cyanoacrylate and polymer on the surface of the orthotropic steel. After the concrete is poured, the modified bentonite in the concrete and the cyanide organic α-cyanoacrylate interact with each other. adsorption, and the modified bentonite and polyacrylate form a three-dimensional network bonding structure, thereby improving the bonding strength of the expansion filler and the orthotropic steel; when the concrete is cured, the expansion agent expands, filling the concrete and the orthotropic steel. The gap between the orthotropic steel and concrete improves the bond strength of the orthotropic steel and concrete, thereby reducing the probability of cracking of the orthotropic steel-concrete composite deck;

3. Under the action of hydration heat, calcium oxide and fly ash in lime soil react with aluminum oxide in bauxite and calcium sulfate in gypsum powder to form calcium sulfoaluminate crystals, and calcium sulfoaluminate crystals fill concrete Therefore, the probability of drying shrinkage of concrete is reduced, so that the bridge deck is not easy to form early cracks;

4. Rhamnose is loaded on calcium-based bentonite, which facilitates the mutual adsorption of modified bentonite and metal cation-containing substances under the action of electric charge; The adsorption strength of lime soil, bauxite and gypsum powder is convenient for calcium-based bentonite to carry the expansion agent to the surface of orthotropic steel, and calcium sulfoaluminate crystals are formed at the interface between orthotropic steel and concrete, thereby reducing the amount of orthotropic steel and concrete. The probability of concrete peeling off each other, thereby reducing the probability of bridge deck cracking;

5. Part of the insulating oil is in contact with ethyl α-cyanoacrylate, which promotes the softening of ethyl α-cyanoacrylate, facilitates the mutual adsorption of ethyl α-cyanoacrylate and the modified bentonite in concrete, and improves the orthotropy between concrete and concrete. Steel bond strength.

Description of drawings

1 is a schematic diagram of a bridge deck structure in an embodiment of the application;

FIG. 2 is a schematic diagram of the overall structure of the shear nail in the embodiment of the application.

Description of reference numbers:

10, orthotropic steel; 11, special-shaped steel plate; 12, panel; 20, steel bar; 30, shear nail; 31, threaded column;

Detailed ways

The present application will be further described in detail below with reference to the examples, comparative examples and accompanying drawings 1-2.

Those without specific conditions in the following examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The raw materials used in the following examples can be obtained from common commercial sources unless otherwise specified.

The water reducing agent is polycarboxylate water reducing agent; the powder is fly ash, the particle size is 325 mesh, and the density is 2.1kg/m ^{3 ;} The fine aggregate is river sand, with a particle size of 20-40 mesh; the length of corrugated steel fiber is 10-15 mm, and the aspect ratio is 60±5; wolframite powder is obtained by grinding wolframite, with a particle size of 400 mesh and FeWO ₄ content More than 80%; the ratio of lime: fly ash: soil in the lime soil is 10:20:70; the bauxite specification is 120 mesh, and the apparent density is 2.6kg/m ³ ; the density of gypsum powder is 2.32kg/m ³ ; calcium The particle size of the base bentonite is 325 meshes, the density is 2.6g/cm ³ ; the molecular weight of rhamnose is 164.16, and the content is 99%;

Preparation example of coated steel fiber

Preparation Example 1

S1, mix 20kg wolframite powder and 130kg vinyl silicone oil uniformly as coating liquid;

S2. Immerse 150kg of corrugated steel fibers in the coating solution for 30 minutes, then dry at 40°C, and then shake and separate into single fibers after drying and solidification, which are coated steel fibers.

Preparation Example 2

S1, mix 35kg wolframite powder and 130kg vinyl silicone oil uniformly as coating liquid;

S2. Immerse 150kg of corrugated steel fibers in the coating solution for 30 minutes, then dry at 40°C, and then shake and separate into single fibers after drying and solidification, which are coated steel fibers.

Preparation Example 3

S1, mix 50kg wolframite powder and 130kg vinyl silicone oil uniformly as coating liquid;

S2. Immerse 150kg of corrugated steel fibers in the coating solution for 30 minutes, then dry at 40°C, and then shake and separate into single fibers after drying and solidification, which are coated steel fibers.

Preparation Example 4

S1. Take 130kg of vinyl silicone oil and mix it uniformly as a coating solution;

S2. Immerse 150kg of corrugated steel fibers in the coating solution for 30 minutes, then dry at 40°C, and then shake and separate into single fibers after drying and solidification, which are coated steel fibers.

Expansion filler preparation example

Preparation Example 5

S1, mix 4kg of limestone, 1kg of bauxite and 3kg of gypsum powder as expansion agent;

S2, 8kg calcium-based bentonite is roasted; 2kg of rhamnose is heated to melting, adds the calcium-based bentonite after roasting, stirs, and cools and drys powder to obtain modified bentonite;

S3. Mix the expansion agent and the modified bentonite uniformly as the expansion filler.

Preparation Example 6

S1, mix 6kg of limestone, 1.5kg of bauxite and 4.5kg of gypsum powder as expansion agent;

S2, 12kg calcium-based bentonite is roasted; 3kg of rhamnose is heated to melting, adds the calcium-based bentonite after roasting, stirs, and cools and drys powder to obtain modified bentonite;

S3. Mix the expansion agent and the modified bentonite uniformly as the expansion filler.

Preparation Example 7

S1, mix 8kg of limestone, 2kg of bauxite and 6kg of gypsum powder as expansion agent;

S2, 16kg calcium-based bentonite is roasted; 4kg of rhamnose is heated to melting, adds the calcium-based bentonite after roasting, stirs, and cools and drys powder to obtain modified bentonite;

S3. Mix the expansion agent and the modified bentonite uniformly as the expansion filler.

Preparation Example 8

The difference from Preparation Example 5 is that 12 kg of calcium-based bentonite and 3 kg of rhamnose are added to S2.

Preparation Example 9

The difference from Preparation Example 5 is that 16 kg of calcium-based bentonite and 4 kg of rhamnose are added to S2.

Preparation Example 10.

The difference from Preparation Example 6 is that 8kg calcium bentonite and 2kg rhamnose are added to S2.

Preparation Example 11

The difference from Preparation Example 6 is that 16 kg of calcium-based bentonite and 4 kg of rhamnose are added to S2.

Preparation Example 12

The difference from Preparation Example 7 is that 8kg calcium bentonite and 2kg rhamnose are added to S2.

Preparation Example 13

The difference from Preparation Example 7 is that 12 kg of calcium-based bentonite and 3 kg of rhamnose are added to S2.

Table 1 Raw material list (kg) of Preparation Example 5 to Preparation Example 13

Preparation example of surface treatment agent

Preparation Example 14

4kg of molten polyacrylate is mixed with 1.5kg of NdFeB powder uniformly as a surface treatment agent.

Preparation Example 15

15kg of molten ethyl α-cyanoacrylate and 1.5kg of NdFeB powder were mixed uniformly as a surface treatment agent.

Preparation Example 16

15kg of molten ethyl α-cyanoacrylate and 4kg of molten polyacrylate were mixed uniformly as a surface treatment agent.

Preparation Example 17

10kg of molten ethyl α-cyanoacrylate, 2kg of molten polyacrylate and 1kg of NdFeB powder were mixed uniformly as a surface treatment agent.

Preparation Example 18

The difference from Preparation 17 is that 4 kg of molten polyacrylate are added.

Preparation Example 19

The difference from Preparation 17 is that 6 kg of molten polyacrylate are added.

Preparation Example 20

15kg of molten ethyl α-cyanoacrylate, 2kg of molten polyacrylate and 1.5kg of NdFeB powder were mixed uniformly as a surface treatment agent.

Preparation Example 21

The difference from Preparation 20 is that 4 kg of molten polyacrylate are added.

Preparation Example 22

The difference from Preparation 21 is that 6 kg of molten polyacrylate are added.

Preparation Example 23

20kg of molten ethyl α-cyanoacrylate, 2kg of molten polyacrylate and 2kg of NdFeB powder were mixed uniformly as a surface treatment agent.

Preparation Example 24

The difference from Preparation 23 is that 4 kg of molten polyacrylate are added.

Preparation Example 25

The difference from Preparation 23 is that 6 kg of molten polyacrylate was added.

Table 2 Raw material table (kg) of Preparation Example 14 to Preparation Example 25

Example

Example 1

S1, 192kg Portland cement, 3kg water reducing agent, 112kg mixing water, 64kg powder and the expansion filler of Preparation Example 5 are evenly stirred as initial mix;

S2. Mix 720kg of coarse aggregate, 420kg of fine aggregate and 28kg of mixing water as a coarse mixture;

S3. Mix and stir the initial mixture and the coarse mixture evenly as a premix;

S4. Add 35 kg of the coated steel fibers prepared in Preparation Example 1 into the premix, and stir evenly to obtain concrete.

Example 2

S1, 276kg Portland cement, 4kg water reducing agent, 116kg mixing water, 92kg powder and the expansion filler of Preparation Example 6 are evenly stirred as initial mix;

S2. Mix 910kg of coarse aggregate, 605kg of fine aggregate and 29kg of mixing water as a coarse mixture;

S3. Mix and stir the initial mixture and the coarse mixture evenly as a premix;

S4. Add 92 kg of the coated steel fibers prepared in Preparation Example 2 into the premix, and stir to obtain concrete.

Example 3

S1, 360kg Portland cement, 5kg water reducing agent, 120kg mixing water, 120kg powder and the expansion filler of Preparation Example 7 are evenly stirred as initial mix;

S2. Mix 1100kg of coarse aggregate, 790kg of fine aggregate and 30kg of mixing water as a coarse mixture;

S3. Mix and stir the initial mixture and the coarse mixture evenly as a premix;

S4, adding 146 kg of the coated steel fibers prepared in Preparation Example 1 into the premix, and stirring uniformly to obtain concrete.

Example 4

The difference from Example 2 is that 92 kg of the coated steel fibers prepared in Preparation Example 4 were added.

Example 5

The difference from Example 2 is that 92 kg of the coated steel fibers prepared in Preparation Example 1 were added.

Example 6

The difference from Example 2 is that 92 kg of the coated steel fibers prepared in Preparation Example 3 were added.

Example 7

The difference from Example 2 is that the expanded filler prepared in Preparation Example 5 is used.

Example 8 to Example 14

The difference from Example 2 is that the expanded fillers prepared in Preparation Examples 7 to 13 are used in sequence.

Example 15

Referring to FIG. 1, a bridge deck structure includes orthotropic steel 10, a steel reinforcement layer and a concrete layer 40, the orthotropic steel 10 includes a special-shaped steel plate 11 and a panel 12, the upper surface of the panel 12 is rectangular, and the special-shaped steel plate 11 is U The special-shaped steel plate 11 is arranged in parallel with the length direction of the upper surface of the panel 12, a plurality of special-shaped 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 special-shaped steel plate 11 and the bottom wall of the panel 12 are fixed by welding. The reinforcement layer includes transverse reinforcement and longitudinal reinforcement, the transverse reinforcement is arranged in parallel with the width direction of the upper surface of the panel 12, the longitudinal reinforcement is arranged in parallel with the longitudinal direction of the upper surface of the panel 12, and a plurality of transverse reinforcement and longitudinal reinforcement are bound to form a reinforcement layer. The top wall of 12 is fixedly connected. The concrete layer 40 is located above the panel 12 , and the concrete layer 40 passes through the steel bar layer and is bonded and fixed with the top wall of the panel 12 , and the steel bar layer is wrapped in the concrete layer 40 .

1 and 2, in order to increase the connection strength between the orthotropic steel 10 and the concrete layer 40, a plurality of shear nails 30 are provided on the panel 12, and the shear nails 30 include a threaded column 31, a connecting circular platform 32 and a top In the cover 33 , the threaded posts 31 are vertically arranged with the top wall of the panel 12 , and the threaded posts 31 are fixedly connected with the top wall of the panel 12 by screws. The connecting round table 32 is coaxially arranged with the threaded column 31 , and the end wall of the large end of the connecting round table 32 is fixedly connected with the top wall of the threaded column 31 , and the end wall of the large end of the connecting round table 32 is in contact with the top wall of the panel 12 . The top cover 33 is a cylinder arranged coaxially with the connecting circular table 32 , and the bottom wall of the top cover 33 is fixedly connected with the end wall connecting the small end of the circular table 32 . An obtuse angle is formed between the shear nail 30 and the top wall of the panel 12, which facilitates filling of concrete and reduces the amount of voids in the concrete.

The implementation principle of Embodiment 15 is:

The transverse bars and longitudinal bars are bound to form a reinforcing bar layer, the reinforcing bar layer is fixed on the panel 12 of the orthotropic steel 10, a plurality of shear nails 30 are screwed on the panel 12 of the orthotropic steel 10, and concrete is poured. The bridge deck structure is formed by bonding and fixing with the panel 12 of the orthotropic steel 10 through the reinforcing bar layer.

Example 16

S1, uniformly spray the surface treatment agent prepared in Preparation Example 14 on the surface of the orthotropic steel 10;

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

S3. Measure the stake out on the bridge deck, and draw the installation position of the shear nail 30;

S4. According to the position of the measured stakeout mark point, the shear nails 30 are installed on the orthotropic steel 10, the reinforcing bars 20 are bound to form a reinforcing bar layer, and are fixedly connected with the orthotropic steel;

S5, the surface treatment agent prepared by spraying preparation example 14 of steel bar 20;

S6, the hot steam sprays the steel bar 20 and the orthotropic steel 10 to soften the surfactant on the orthotropic steel 10 and the steel bar 20, and then uses the concrete prepared in Example 2 for pouring, and the hot steam spray does not exceed the amount before the concrete is poured For 10 minutes, the plug-in vibrating rod is used to vibrate in layers during the concrete pouring process, and the vibrating rod is inserted quickly and slowly pulled out to reduce the amount of pores in the concrete;

S7. Manually smooth the upper surface of the concrete, and use the steam curing method to maintain the concrete until the concrete is formed and the bridge deck is formed.

Example 17 to Example 27

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

Example 28

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

Comparative ratio

Comparative Example 1

The difference between this comparative example and Example 2 is that no coated steel fibers are added, and 92 kg of corrugated steel fibers are added.

Comparative Example 2

The difference between this comparative example and Example 2 is that no expansion filler is added.

Comparative Example 3

The difference between this comparative example and Example 2 is that no modified bentonite is added.

Comparative Example 4

The difference between this comparative example and Example 15 is that no surfactant was sprayed on the orthotropic steel and the steel bar.

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

performance test

experiment method

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

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

4. The shrinkage rate (%) of concrete is measured by the method in "GB/T50082-2009 Standard for Long-term Performance and Durability Test of Ordinary Concrete", and the test results are shown in Table 4.

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

Table 4 Data table of test results of Example 1 to Example 14 and Comparative Example 1 to Comparative Example 3

Combined with Example 1, Example 2 and Example 3 and combined with Table 4, by adjusting the ratio of Portland cement, water reducing agent, mixing water, powder, coarse aggregate, fine aggregate, coated steel fiber and expansion filler The type and amount of addition can improve the compressive strength and flexural strength of concrete and reduce the shrinkage rate of concrete.

Combining Example 2 and Comparative Example 1 with Table 4, it can be seen that compared with the addition of corrugated steel fibers, the addition of coated steel fibers improves the compressive strength and flexural strength of concrete, and reduces the shrinkage rate of concrete. The coated steel fibers include corrugated steel fibers and a coating liquid coated on the surface of the corrugated steel fibers. The coating liquid is mixed with vinyl silicone oil and wolframite powder. Wolframite powder is adhered to the surface of the corrugated steel fiber by vinyl silicone oil, so that the surface of the corrugated steel fiber forms a flexible coating, and the corrugated steel fiber is not easy to break, thus Improve the compressive strength and flexural strength of concrete. The shrinkage rate of coated steel fibers is lower than that of concrete. During the evaporation of water in the concrete, the coated steel fibers adhere to support cement particles and aggregates, so that the concrete is not easy to shrink, thereby reducing the shrinkage rate of the concrete.

Combining Example 2 and Example 4 with Table 4, it can be seen that the addition of wolframite powder improves the flexural strength of concrete and reduces the shrinkage rate of concrete. Tungsten in wolframite powder reacts with sodium hydroxide solution in concrete to form crude sodium tungstate, which reduces the content of free sodium ions in concrete and reduces the probability of concrete being corroded by alkali, thereby improving the flexural strength of concrete. The iron ions in the black house powder form a dense film with air and water molecules, which blocks the water and the coated steel fibers, reduces the probability of corrosion of the coated steel fibers, and improves the compressive strength and flexural strength of concrete. The metal cations in wolframite powder adsorb the modified bentonite in the expansion filler, thereby improving the bonding strength between the corrugated steel fiber and the expansion agent. When the concrete expands, the expansion agent fills the pores of the expansion agent, which improves the self-tightness of the concrete. , so that the concrete is not easy to shrink, thereby reducing the shrinkage of the concrete.

In combination with Example 2, Example 5 and Example 6 and in combination with Table 4, it can be seen that with the increase in the weight ratio of wolframite powder to vinyl silicone oil, the compressive strength and flexural strength of concrete both increase first and then decrease, The shrinkage of concrete first decreases and then increases. The reason for the decrease in the compressive strength of concrete is that the addition of wolframite powder reduces the bonding strength of the coating solution and the corrugated steel fibers. During concrete mixing, the coating on the surface of the corrugated steel fibers is easily peeled off, and the coating has no effect on the corrugated steel fibers. The buffering effect of the steel fibers is reduced, so that the coated steel fibers are easily broken and the compressive strength of the concrete is reduced.

Combining Example 2 and Comparative Example 2 with Table 4, it can be seen that the addition of expansion fillers improves the flexural strength of concrete and reduces the shrinkage rate of concrete. Expansion fillers include expansion agents and modified bentonites, expansion agents include di-lime, bauxite and gypsum powder, and modified bentonites include calcium-based bentonite and rhamnose. Rhamnose is attached to the surface and pores of calcium-based bentonite, and rhamnose acts as an anionic surfactant, while the presence of metal cations in di-lime, bauxite, and gypsum powder increases the efficiency of di-lime, bauxite, and gypsum powder with calcium. Bonding strength of base bentonite. Under the action of the heat of hydration, calcium oxide and fly ash in the lime soil react with aluminum oxide in the bauxite and calcium sulfate in the gypsum powder to form calcium sulfoaluminate crystals, and the calcium sulfoaluminate crystals fill the concrete in the concrete. The pores improve the self-compactness of the concrete, thereby reducing the probability of concrete shrinkage, reducing the shrinkage rate of the concrete, and then improving the compressive strength and flexural strength of the concrete.

Combining Example 2, Comparative Example 2 and Comparative Example 3 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 concrete, and reduces the shrinkage rate of concrete. The modified bentonite is loaded with limestone, bauxite and gypsum powder, which is convenient for the three to react 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 are mutually adsorbed, which improves the expansion of the filler. The bonding strength with the coated steel fibers, the expansion agent generates calcium sulfoaluminate crystals, which tightly wrap the coated steel fibers, reducing the probability of the formation of gaps between the slurry and the coated steel fibers due to concrete shrinkage, thereby reducing the The amount of porosity in the concrete reduces the shrinkage rate of the concrete and increases the flexural strength and compressive strength of the concrete.

Combined with Example 2 and Examples 7 to 14 and Table 4, by adding the ratio of expansion agent and modified bentonite, the flexural strength and compressive strength of concrete are improved, and the shrinkage rate of concrete is reduced.

Combined with Example 2, Example 11 and Example 12 and combined with Table 4, it can be seen that under the condition of the same amount of expansion agent added, increasing the amount of modified bentonite added, the compressive strength and flexural strength of concrete are both higher. Increase and then decrease, the shrinkage of concrete decreases first and then increases. Modified bentonite includes calcium-based bentonite and rhamnose. Rhamnose improves the adsorption efficiency and adsorption capacity of calcium-based bentonite to swelling agent. The self-compactness of concrete is improved, the compressive strength and flexural strength of concrete are improved, and the shrinkage rate is reduced. However, the specific surface area of calcium-based bentonite is relatively large. With the increase of the addition amount of calcium-based bentonite and rhamnose, part of the swelling agent enters the gap of calcium-based bentonite, and calcium-based bentonite hinders the contact between the swelling agent and water, so that the swelling agent The expansion efficiency of concrete decreases, the compressive strength and flexural strength of concrete decrease, and the shrinkage rate increases.

Combined with Example 2, Example 9 and Example 14, and combined with Table 4, it can be seen that when the addition amount of the modified bentonite is unchanged, the addition amount of the expansion agent is increased, and the compressive strength and flexural strength of the concrete are both. First increase and then decrease, the shrinkage of concrete decreases first and then increases. Expansion agents include di-lime, bauxite and gypsum powder. Under the action of hydration heat, calcium oxide and fly ash in di-lime soil react with aluminum oxide in bauxite and calcium sulfate in gypsum powder to form sulfoaluminate. Calcium crystals, calcium sulfoaluminate crystals fill the pores in the concrete, thereby reducing the concrete shrinkage rate, the concrete is not easy to form early cracks, and the compressive strength and flexural strength of the concrete are improved. With the addition of lime soil, bauxite and gypsum powder, the modified bentonite can only support part of the lime soil, bauxite and gypsum powder, other lime soil, bauxite and gypsum powder are separated from the modified bentonite, and the lime soil, bauxite and gypsum powder are separated from the modified bentonite. Dispersed in concrete, lime soil, bauxite and gypsum powder are not easy to contact and react during concrete curing, which reduces the expansion efficiency of the expansion agent, reduces the compressive strength and flexural strength of concrete, and increases the shrinkage rate.

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

Combining Example 23 and Comparative Example 4 with Table 5, it can be seen that the addition of surfactant improves the bond strength between concrete and orthotropic steel. The surfactants include α-cyanoacrylate, polyacrylate and NdFeB powder, the surface treatment agent is coated on the surface of orthotropic steel, and the neodymium is uniformly mixed with α-cyanoacrylate and polyacrylate. The iron boron powder 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.

Combining Example 16 and Example 23 and combining with Table 5, it can be seen that the addition of α-ethyl cyanoacrylate improves the positive tensile bond strength between concrete and trade steel. The modified bentonite in the concrete and the cyanide organic compound α-cyanoacrylate are mutually adsorbed, and the modified bentonite is bonded with the high polymer, thereby improving the bonding strength between the concrete and the orthotropic steel.

Combining Example 17 and Example 23 with Table 5, it can be seen that the addition of polyacrylate improves the positive tensile bond strength between the concrete and the normal trade section steel. Polyacrylate and modified bentonite form a three-dimensional network structure, thereby improving the bonding strength between concrete and orthotropic steel; polyacrylate forms a waterproof film on the surface of orthotropic steel, preventing water molecules from infiltrating concrete and orthotropic steel. between the anisotropic steels, thereby reducing the probability of peeling off the concrete and the orthotropic steel, thereby improving the bond strength between the concrete and the orthotropic steel.

Combining Example 18 and Example 23 and combining with Table 5, it can be seen that the addition of NdFeB powder improves the positive tensile bond strength between concrete and normal traded steel. NdFeB 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. The rhamnose in the modified bentonite forms a cyclic structure complex with metal ions, which improves the adsorption strength of the calcium-based bentonite to di-lime, bauxite and gypsum powder, and facilitates the calcium-based bentonite to carry the swelling agent to the orthotropic steel. On the surface, calcium sulfoaluminate crystals are formed at the interface of orthotropic steel and concrete, thereby reducing the probability of orthotropic steel and concrete peeling off each other, and improving the bonding strength of concrete and orthotropic steel.

With reference to Examples 19 to 27 and Table 5, the bonding strength between concrete and orthotropic steel is improved by adjusting the addition amounts of α-ethyl cyanoacrylate, polyacrylate and NdFeB powder.

Combining Example 22, Example 23 and Example 24 with Table 5, it can be seen that under the condition that the addition amount of α-ethyl cyanoacrylate and NdFeB powder is unchanged, increasing the addition amount of polyacrylate, concrete The positive tensile bond strength with orthotropic steel increases first and then decreases. The reason for the decrease in the positive tensile bond strength is that the water-repellent film generated by the polyacrylate hinders the contact between α-cyanoacrylate and the orthotropic steel, thereby reducing the bonding strength of the surface treatment agent and the orthotropic steel, thereby reducing the The bond strength between concrete and orthotropic steel.

Combined with Example 20, Example 23 and Example 26 and combined with Table 5, it can be seen that under the condition that the addition amount of polyacrylate remains unchanged, increasing the addition amount of α-ethyl cyanoacrylate and NdFeB powder, concrete The positive tensile bond strength with orthotropic steel increases first and then decreases. The reason for the decrease of positive tensile bond strength is that the content of polyacrylate in the surface treatment agent decreases, the bond between polyacrylate and modified bentonite in concrete is hindered, and the bond strength between concrete and orthotropic steel decreases.

Combining Example 23 and Example 28 with Table 5, it can be seen that the addition of insulating oil improves the positive tensile bond strength between the concrete and the traded steel. Part of the insulating oil is contacted with ethyl α-cyanoacrylate, which promotes the softening of ethyl α-cyanoacrylate, facilitates the mutual adsorption of ethyl α-cyanoacrylate and modified bentonite in concrete, and improves the adhesion between concrete and orthotropic steel. Bond strength.

This specific embodiment is only an explanation of the application, and it does not limit the application. Those skilled in the art can make modifications to the embodiment without creative contribution as needed after reading this specification, but as long as the rights of the application are All claims are protected by patent law.

Claims (9)

1. The construction process of the steel-concrete composite beam cable-stayed bridge panel capable of reducing cracking is characterized by comprising the following steps of:

s1, spraying a surface treatment agent on the surface of orthotropic steel (10);

s2, mounting orthotropic steel (10), and cleaning and checking bridge deck;

s3, measuring and lofting;

s4, installing shear nails (30) and binding steel bars (20);

s5, spraying a surface treating agent on the steel bar (20);

s6, spraying hot steam, and pouring concrete, wherein the spraying of the hot steam is not more than 10min before the pouring of the concrete;

s7, dough collection and maintenance;

the concrete comprises the following raw materials in parts by weight: 192-360 parts of Portland cement; 3-5 parts of a 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 coating steel fiber; 18-36 parts of an expansion filler;

the swelling filler comprises a swelling agent and modified bentonite, and the weight ratio of the swelling agent to the modified bentonite is (2-8): 5;

the surface treating agent comprises alpha-ethyl cyanoacrylate, high polymer and neodymium iron boron powder, wherein the weight ratio of the alpha-ethyl cyanoacrylate to the polyacrylate to the neodymium iron boron powder is 10: (2-6): 1.

2. the process of claim 1, wherein the polymer is polyacrylate.

3. The construction process for the cable-stayed bridge deck of the steel-concrete composite beam capable of reducing the cracking as claimed in claim 2, wherein the expanding agent comprises two-ash-soil, alumina and gypsum powder, and the weight ratio of the two-ash-soil, the alumina and the gypsum powder is 4:1:3.

4. the construction process for the cable-stayed bridge panel of the steel-concrete composite beam capable of reducing cracking according to claim 3, wherein the modified bentonite comprises calcium bentonite and rhamnose, and the weight ratio of the calcium bentonite to the rhamnose is 4:1.

5. the construction process of the steel-concrete composite beam cable-stayed bridge panel capable of reducing the cracking according to claim 4, wherein the preparation step of the modified bentonite comprises the following steps: roasting calcium bentonite; heating rhamnose to melt, adding the roasted calcium-based bentonite, stirring uniformly, cooling, drying and powdering to obtain the modified bentonite.

6. The construction process for a cable-stayed bridge deck by using a reinforced concrete composite beam capable of reducing cracking as claimed in claim 4, wherein the coating steel fibers comprise corrugated steel fibers and a coating liquid, and the coating liquid is coated on the outer surfaces of the corrugated steel fibers.

7. The construction process of the steel-concrete composite beam cable-stayed bridge panel capable of reducing cracking according to claim 6, wherein the coating liquid comprises wolframite powder and vinyl silicone oil, and the weight ratio of the wolframite powder to the vinyl silicone oil is (2-5): 13.

8. the construction process of the cable-stayed bridge deck of the steel-concrete composite beam for reducing the cracking according to claim 1, wherein the curing manner in the step S6 is steam curing.

9. The construction process for the cable-stayed bridge deck of the steel-concrete composite beam capable of reducing the cracking as claimed in claim 1, wherein an inserted vibrating bar is adopted for layered vibration in the concrete pouring process of S5.

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