A crack-resistant concrete reinforced steel truss floor deck and its preparation method

Abstract

The present application relates to the technical field of concrete floor slabs, and specifically discloses a crack-resistant concrete steel truss floor slab and its preparation method. A crack-resistant concrete steel truss floor slab comprises: a steel truss and a crack-resistant concrete layer cast on the steel truss. The raw materials of the crack-resistant concrete layer include: cement, fly ash, slag powder, machine-made sand, gravel, water, water reducer, β-alanine solution, carbon nanotube-rectorite nano-intercalation material and CO2 curing powder; the carbon nanotube-rectorite nano-intercalation material is made by inserting acidified carbon nanotubes into the interlayer of sodium-based rectorite, and the CO2 curing powder is made by grinding industrial waste slag after supercritical CO2 treatment. The present application scheme significantly improves the crack resistance of the floor slab by optimizing the concrete components and the steel truss structure.

Description

Technical Field

[0001] The present application relates to the technical field of concrete floor slabs, and more specifically, to a crack-resistant concrete reinforced steel truss floor slab and a preparation method thereof. Background Art

[0002] As a crucial component of the floor structure, floor decks play a crucial role in bearing and transmitting floor loads. Traditional floor decks typically consist of a combination of steel trusses and a concrete layer. The steel trusses provide structural strength, while the concrete layer protects the steel, distributes the load, and enhances structural integrity. This structural form is widely used in conventional buildings. However, with the continuous advancement of construction technology and the increasing complexity of building structures, the performance requirements for floor decks are also increasing, especially in terms of crack resistance.

[0003] At present, the floor decking in the prior art is formed by welding steel trusses, fixing corrugated steel plates, and pouring a concrete layer on top to form a complete floor decking structure. In terms of concrete components, the traditional formula usually includes cement, sand, stone, water and necessary admixtures. For example, the application document with publication number CN105421631A discloses a slag floor decking for construction and a preparation method thereof. The concrete components of the floor decking mainly include slag, silica fume, fly ash, alkaline activator, water, wood chips and polypropylene fiber. The above-mentioned concrete components use alkali-activated slag cementitious materials. The alkaline activator can significantly improve the performance of the alkali-activated slag cementitious materials, thereby improving the floor decking to have better strength and durability.

[0004] However, existing floor decking systems still suffer from significant deficiencies in crack resistance. While the addition of admixtures such as slag, silica fume, and fly ash, as well as additives like polypropylene fiber, to concrete components improves strength and durability to a certain extent, these components are limited in their effectiveness in suppressing early shrinkage cracking and crack propagation under long-term loads. In particular, alkali-activated slag cementitious materials, while capable of improving concrete's mechanical properties, suffer from a high shrinkage rate, which can easily lead to microcracks in the concrete layer during the hardening process, thus compromising the overall crack resistance of the floor deck. Summary of the Invention

[0005] In order to improve the crack resistance of floor decking and thus meet the higher requirements of modern building structures on floor decking performance, the present application provides a crack-resistant concrete reinforced truss floor decking and a preparation method thereof.

[0006] The present application provides a crack-resistant concrete reinforced truss floor decking plate adopting the following technical solution:

[0007] A crack-resistant concrete reinforced truss floor deck comprises a reinforced truss and a crack-resistant concrete layer cast on the reinforced truss. The crack-resistant concrete layer is made of the following raw materials in parts by weight: 400-450 parts of cement, 80-120 parts of fly ash, 50-70 parts of slag powder, 650-800 parts of machine-made sand, 500-650 parts of crushed stone, 200-230 parts of water, 5-10 parts of a water reducer, 2-5 parts of a beta-alanine solution, 40-80 parts of a carbon nanotube-rectorite nano-intercalation material, and 60-100 parts of a CO2 curing powder. The carbon nanotube-rectorite nano-intercalation material is made by inserting acidified carbon nanotubes between sodium-based rectorite layers, and the CO2 curing powder is made by grinding industrial waste slag after supercritical CO2 treatment.

[0008] This application scheme significantly improves the crack resistance of the floor decking by optimizing the concrete components and the steel truss structure. The steel truss is welded by upper chord steel bars, lower chord steel bars, web bars and corrugated steel plates. The web bars are arranged in a sinusoidal waveform. The web bars, upper chord steel bars and lower chord steel bars form a diamond support grid. The corrugated steel plate is fixed to the bottom of the lower chord steel bars. The surface of the corrugated steel plate is provided with a plurality of equidistant and parallel ridges. The length direction of the ridges is perpendicular to the length direction of the upper chord steel bars. The sinusoidal wave web bars and diamond support grid design enhance the overall stiffness of the steel truss and reduce the risk of cracking caused by uneven stress on the concrete layer. Carbon nanotube-rectorite nano-intercalation material, CO2 curing powder, β-alanine solution and sodium alginate solution are introduced into the anti-cracking concrete layer to form a multi-scale anti-crack reinforcement system. Carbon nanotubes are inserted between the rectorite layers to form an intercalated structure, which enhances the performance of the internal interface transition zone of the concrete through physical barrier and chemical bonding; the supercritical CO2 treatment in the CO2 curing powder promotes the dissolution of the active components of the waste slag, generates calcium carbonate crystals to fill the pores, and reduces the porosity; β-alanine solution and sodium alginate solution improve the internal stress distribution of the concrete, enhance the tensile strength and deformation capacity, thereby effectively inhibiting the initiation and expansion of cracks, and effectively enhancing the crack resistance of the concrete reinforced truss floor deck.

[0009] Optionally, the carbon nanotube-rectorite nano-intercalation material is prepared by the following method:

[0010] (1) Reflux acidify multi-walled carbon nanotubes in mixed acid for 2-4 h, wash by centrifugation, and then dry naturally to obtain acidified carbon nanotubes. Disperse the acidified carbon nanotubes in deionized water and ultrasonicate for 30-60 min to obtain a carbon nanotube suspension.

[0011] (2) Dispersing rectorite powder in carbon nanotube suspension and stirring for 2-4 hours, drying the mixture after stirring, placing the mixture in an internal mixer, setting the mixer temperature to 200-210 ° C, the rotor speed to 50-60 r / min, and the melt mixing time to 50-60 min. After the internal mixer is completed, the carbon nanotube-rectorite nano-intercalation material is obtained.

[0012] By adopting the above technical solution, acid modification forms oxygen-containing functional groups on the surface of carbon nanotubes through the oxidation effect of mixed acid, thereby improving their hydrophilicity and dispersibility; during the mixing process, the interlayers of rectorite expand, and the carbon nanotubes are inserted into the interlayers to form an intercalation complex, which enhances the internal stress transmission capacity of concrete and inhibits crack expansion through physical intercalation and chemical bonding.

[0013] Optionally, in step (1), the mixed acid comprises sulfuric acid and nitric acid in a mass ratio of 1:(2-3); the mass fraction of the sulfuric acid is 65%-70%; and the mass fraction of the nitric acid is 65%-68%.

[0014] The above-mentioned mixed acid ratio avoids structural defects in the carbon nanotubes caused by over-acidification, thereby preserving their high strength and high modulus properties. The optimized acidification conditions allow the carbon nanotubes to achieve surface modification while maintaining mechanical properties, providing active sites for subsequent intercalation with rectorite.

[0015] Optionally, in step (1), the mass ratio of the multi-walled carbon nanotubes to the mixed acid is 1:(10-15); and the mass ratio of the acidified carbon nanotubes to deionized water is 1:(30-40).

[0016] Optionally, in step (2), the amount of rectorite powder used is 10-20 times the mass of the acidified carbon nanotubes.

[0017] Optionally, the CO2 curing powder is prepared by the following method:

[0018] Crushing steel slag, blast furnace slag or slag to a particle size of 2-5 mm to obtain powder, adding the powder and grinding aid into a reactor, heating to 100-120 ° C, and then pumping CO2 into it until the pressure reaches 15-30 MPa, and then starting to stir for 4-6 hours, and finally obtaining CO2-cured micropowder after stirring.

[0019] By adopting the above technical solution, supercritical CO2 penetrates into the interior of the waste slag particles under high pressure and high temperature conditions, reacts with active ingredients to form calcium carbonate crystals, and improves the morphology and surface activity of the micropowder particles; the grinding aid accelerates the dissolution of calcium ions, which is used to promote the carbonization reaction kinetics process, generate a dense calcium carbonate network structure, reduce the shrinkage stress of concrete, and inhibit the development of cracks.

[0020] Optionally, the grinding aid is 0.5-1% of the powder, and the grinding aid is any one of sodium lignin sulfonate and triethanolamine.

[0021] Optionally, the concentration of the β-alanine solution is 40%-50%.

[0022] Optionally, the raw materials for the anti-cracking concrete layer further include 1-4 parts of sodium alginate solution.

[0023] By adopting the above technical solution, β-alanine forms hydrogen bonds or covalent bonds with cement hydration products, enhancing the performance of the interface transition zone and reducing crack initiation; sodium alginate forms a three-dimensional gel network in concrete, physically blocking the crack expansion path, while absorbing the crack expansion energy through the energy dissipation mechanism, thereby improving the toughness of concrete.

[0024] The present application also provides a method for preparing a crack-resistant concrete reinforced steel truss floor deck, which adopts the following technical solution:

[0025] A method for preparing a crack-resistant concrete reinforced steel truss floor deck comprises the following steps:

[0026] S1. Tie the steel bars and corrugated steel plates according to the design requirements and weld them to form a steel truss;

[0027] S2. Mix cement, fly ash, slag powder, machine-made sand, and crushed stone evenly, then add water, water reducer, polyvinyl alcohol solution, and sodium alginate solution and stir to form a uniform mixture, then add carbon nanotube-rectorite nano-intercalation material and CO2 curing powder and continue stirring to obtain crack-resistant concrete, pour the crack-resistant concrete on the steel truss, vibrate it with a vibrating device to make it dense, and then cure it for 18-24 hours to obtain the crack-resistant concrete steel truss floor deck.

[0028] By adopting the above technical solution, the step-by-step mixing process first mixes dry materials and wet materials to form a uniform mixture, and then adds nano-intercalated materials and micropowders to ensure their uniform dispersion in the concrete; the vibrating equipment eliminates bubbles inside the concrete through mechanical vibration, improves density, reduces porosity, and thus reduces the risk of cracks.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. This application adopts a unique steel truss structure and a collaborative design of crack-resistant concrete layers, which significantly improves the crack resistance of the floor decking. In terms of the crack-resistant concrete layer, by optimizing the concrete components, new materials such as carbon nanotube-rectorite nano-intercalation materials and CO2 curing powders are introduced. Carbon nanotubes are inserted between the rectorite layers to form an intercalation structure, which not only limits the expansion of cracks through physical barriers, but also enhances the performance of the internal interface transition zone of the concrete through chemical bonding, thereby improving the integrity and crack resistance of the concrete. The supercritical CO2 treatment in the CO2 curing powder promotes the dissolution of the active components of the waste slag, generates calcium carbonate crystals to fill the pores, reduces the porosity of the concrete, and reduces stress concentration and crack initiation caused by the pores. The synergistic effect of this structure and material enables the floor decking to better resist the generation and development of cracks during load bearing and long-term use, thereby improving the reliability and durability of the floor decking.

[0031] 2. The carbon nanotube-rectorite nano-intercalation material in this application is prepared by a specific acidification and mixing process. Acidification modification forms oxygen-containing functional groups on the surface of the carbon nanotubes, which improves its hydrophilicity and dispersibility, and provides active sites for subsequent intercalation composites with rectorites. During the mixing process, the rectorite interlayers expand, and the carbon nanotubes are inserted into the interlayers to form intercalation composites, which enhances the stress transmission capacity of the concrete. The CO2 curing powder accelerates the dissolution of calcium ions and promotes the carbonization reaction kinetics through supercritical CO2 treatment and complexation with triethanolamine, generating a dense calcium carbonate network structure, reducing the shrinkage stress of concrete, inhibiting the development of cracks, ensuring the high performance of the crack-resistant concrete layer, and thus improving the crack resistance of the floor deck.

[0032] 3. A large amount of industrial waste residue, such as steel slag, blast furnace slag or slag, is used in the anti-cracking concrete layer of the present application. These waste residues are processed and made into CO2 curing powder, which not only realizes the resource utilization of waste residues and reduces the pollution of waste residues to the environment, but also reduces the dependence on natural resources and reduces production costs. In addition, since the crack resistance of the floor decking has been significantly improved, the costs caused by crack repair and reinforcement in the later stage are reduced, the service life of the floor decking is extended, and it has a high cost performance. Therefore, the anti-cracking concrete steel truss floor decking of the present application not only meets the higher performance requirements of modern building structures for floor decking, but also has good environmental protection and economy. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the embodiments.

[0034] Preparation example of carbon nanotube-rectorite nanointercalation material

[0035] Preparation Example 1

[0036] The carbon nanotube-rectorite nano-intercalation material is prepared by the following method:

[0037] (1) 1 kg of multi-walled carbon nanotubes was refluxed and acidified in 10 kg of mixed acid for 2 h. The mixed acid included 3.3 kg of 65% sulfuric acid and 6.7 kg of 65% nitric acid. After centrifugal washing, the acidified carbon nanotubes were naturally dried. 1 kg of the acidified carbon nanotubes was dispersed in 30 kg of deionized water and ultrasonicated for 30 min to obtain a carbon nanotube suspension.

[0038] (2) 10 kg of rectorite powder was dispersed in the carbon nanotube suspension and stirred for 2 h. After the stirring was completed, the mixture was dried to obtain a mixture. The mixture was placed in an internal mixer, and the mixer temperature was set to 200 ° C, the rotor speed was set to 50 r / min, and the melt mixing time was set to 50 min. After the internal mixer was completed, the carbon nanotube-rectorite nano-intercalation material was obtained.

[0039] Preparation Example 2

[0040] The carbon nanotube-rectorite nano-intercalation material is prepared by the following method:

[0041] (1) 1 kg of multi-walled carbon nanotubes were refluxed and acidified in 12 kg of mixed acid, which included 3.4 kg of 68% sulfuric acid and 8.6 kg of 66% nitric acid. After centrifugal washing, the acidified carbon nanotubes were naturally dried. 1 kg of the acidified carbon nanotubes were dispersed in 35 kg of deionized water and ultrasonically treated for 45 min to obtain a carbon nanotube suspension.

[0042] (2) 15 kg of rectorite powder was dispersed in the carbon nanotube suspension and stirred for 3 h. After the stirring, the mixture was dried to obtain a mixture. The mixture was placed in an internal mixer, and the mixer temperature was set to 205 ° C, the rotor speed was set to 55 r / min, and the melt mixing time was set to 55 min. After the internal mixer was completed, the carbon nanotube-rectorite nano-intercalation material was obtained.

[0043] Preparation Example 3

[0044] The carbon nanotube-rectorite nano-intercalation material is prepared by the following method:

[0045] (1) 1 kg of multi-walled carbon nanotubes were refluxed and acidified in 15 kg of mixed acid for 4 h. The mixed acid included 3.75 kg of 70% sulfuric acid and 11.25 kg of 68% nitric acid. After centrifugal washing, the acidified carbon nanotubes were naturally dried. 1 kg of the acidified carbon nanotubes were dispersed in 40 kg of deionized water and ultrasonically treated for 45 min to obtain a carbon nanotube suspension.

[0046] (2) 20 kg of rectorite powder was dispersed in the carbon nanotube suspension and stirred for 4 h. After the stirring, the mixture was dried to obtain a mixture. The mixture was placed in an internal mixer, and the mixer temperature was set to 210 ° C, the rotor speed was set to 60 r / min, and the melt mixing time was set to 60 min. After the internal mixer was completed, the carbon nanotube-rectorite nano-intercalation material was obtained.

[0047] Preparation Example 4

[0048] The carbon nanotube-rectorite nano-intercalation material is different from the preparation example 1 in that 10 kg mass fraction of sulfuric acid is used instead of mixed acid for reflux acidification in step (1).

[0049] Preparation example of CO2 curing micro powder

[0050] Preparation Example 5

[0051] CO2 curing micropowder is prepared by the following method:

[0052] 100 kg of steel slag was crushed to a particle size of 2 mm to obtain powder. 100 kg of powder and 0.5 kg of sodium lignin sulfonate were added to a reactor, heated to 100 ° C, and then CO2 was pumped in until the pressure reached 30 MPa. Then stirring was started for 4 hours. After stirring, CO2-cured micropowder was obtained.

[0053] Preparation Example 6

[0054] CO2 curing micropowder is prepared by the following method:

[0055] 100 kg of blast furnace slag was crushed to a particle size of 4 mm to obtain powder. 100 kg of powder and 0.8 kg of sodium lignin sulfonate were added to a reactor, heated to 110 ° C, and then CO2 was pumped in until the pressure reached 25 MPa. Then stirring was started for 5 hours. After stirring, CO2-cured micropowder was obtained.

[0056] Preparation Example 7

[0057] CO2 curing micropowder is prepared by the following method:

[0058] 100 kg of slag was crushed to a particle size of 5 mm to obtain powder. 100 kg of powder and 1.0 kg of sodium lignin sulfonate were added to a reactor, heated to 120°C, and then CO2 was pumped in until the pressure reached 15 MPa. Then stirring was started for 6 hours, and CO2-cured micropowder was obtained after stirring was completed.

[0059] Example

[0060] Example 1

[0061] A crack-resistant concrete steel bar truss floor deck, comprising:

[0062] The steel truss is welded from upper and lower chord steel bars, web bars, and corrugated steel plates. The web bars are arranged in a sinusoidal waveform, forming a diamond-shaped support grid with the upper and lower chord bars. The corrugated steel plates are welded to the bottom of the lower chord steel bars, and the surface of the corrugated steel plates is provided with multiple equidistant and parallel ridges, with the ridges running perpendicular to the length of the upper chord steel bars.

[0063] The anti-cracking concrete layer is cast above the steel truss and the corrugated steel plate. The raw material components and proportions of the anti-cracking concrete layer are shown in Table 1; the mass concentration of the β-alanine solution is 40%; the carbon nanotube-rectorite nano-intercalation material is the carbon nanotube-rectorite nano-intercalation material prepared in Preparation Example 1; and the CO2 curing powder is the CO2 curing powder prepared in Preparation Example 5.

[0064] A method for preparing a crack-resistant concrete reinforced steel truss floor deck comprises the following steps:

[0065] S1. Tie the steel bars and corrugated steel plates according to the design requirements and weld them to form a steel truss;

[0066] S2. Mix cement, fly ash, slag powder, machine-made sand and gravel evenly, then add water, water reducer, polyvinyl alcohol solution and sodium alginate solution and stir into a uniform mixture, then add carbon nanotube-rectorite nano-intercalation material and CO2 curing powder and continue stirring to obtain crack-resistant concrete, pour the crack-resistant concrete on the steel truss, vibrate it with a vibrating device to make it dense, and then cure it for 18 hours to obtain the crack-resistant concrete steel truss floor deck.

[0067] Example 2

[0068] A crack-resistant concrete steel bar truss floor deck, comprising:

[0069] The steel truss is welded from upper and lower chord steel bars, web bars, and corrugated steel plates. The web bars are arranged in a sinusoidal waveform, forming a diamond-shaped support grid with the upper and lower chord bars. The corrugated steel plates are welded to the bottom of the lower chord steel bars, and the surface of the corrugated steel plates is provided with multiple equidistant and parallel ridges, with the ridges running perpendicular to the length of the upper chord steel bars.

[0070] The anti-cracking concrete layer is cast above the steel truss and the corrugated steel plate. The raw material components and proportions of the anti-cracking concrete layer are shown in Table 1; the mass concentration of the β-alanine solution is 45%; the carbon nanotube-rectorite nano-intercalation material is the carbon nanotube-rectorite nano-intercalation material prepared in Preparation Example 2; and the CO2 curing powder is the CO2 curing powder prepared in Preparation Example 6.

[0071] A method for preparing a crack-resistant concrete reinforced steel truss floor deck comprises the following steps:

[0072] S1. Tie the steel bars and corrugated steel plates according to the design requirements and weld them to form a steel truss;

[0073] S2. Mix cement, fly ash, slag powder, machine-made sand and gravel evenly, then add water, water reducer, polyvinyl alcohol solution and sodium alginate solution and stir into a uniform mixture, then add carbon nanotube-rectorite nano-intercalation material and CO2 curing powder and continue stirring to obtain crack-resistant concrete, pour the crack-resistant concrete on the steel truss, vibrate it with a vibrating device to make it dense, and then cure it for 22 hours to obtain the crack-resistant concrete steel truss floor deck.

[0074] Example 3

[0075] A crack-resistant concrete steel bar truss floor deck, comprising:

[0076] The steel truss is welded from upper and lower chord steel bars, web bars, and corrugated steel plates. The web bars are arranged in a sinusoidal waveform, forming a diamond-shaped support grid with the upper and lower chord bars. The corrugated steel plates are welded to the bottom of the lower chord steel bars, and the surface of the corrugated steel plates is provided with multiple equidistant and parallel ridges, with the ridges running perpendicular to the length of the upper chord steel bars.

[0077] The anti-cracking concrete layer is cast above the steel truss and the corrugated steel plate. The raw material components and proportions of the anti-cracking concrete layer are shown in Table 1; the mass concentration of the β-alanine solution is 50%; the carbon nanotube-rectorite nano-intercalation material is the carbon nanotube-rectorite nano-intercalation material prepared in Preparation Example 3; and the CO2 curing powder is the CO2 curing powder prepared in Preparation Example 7.

[0078] A method for preparing a crack-resistant concrete reinforced steel truss floor deck comprises the following steps:

[0079] S1. Tie the steel bars and corrugated steel plates according to the design requirements and weld them to form a steel truss;

[0080] S2. Mix cement, fly ash, slag powder, machine-made sand and gravel evenly, then add water, water reducer, polyvinyl alcohol solution and sodium alginate solution and stir into a uniform mixture, then add carbon nanotube-rectorite nano-intercalation material and CO2 curing powder and continue stirring to obtain crack-resistant concrete, pour the crack-resistant concrete on the steel truss, vibrate it with a vibrating device to make it dense, and then cure it for 22 hours to obtain the crack-resistant concrete steel truss floor deck.

[0081] Table 1 Raw material components and proportions of the anti-cracking concrete layer in Examples 1-3 (kg)

[0082]

[0083] Example 4

[0084] A crack-resistant concrete reinforced truss floor deck is different from Example 1 in that the carbon nanotube-rectorite nano-intercalation material in this embodiment is the carbon nanotube-rectorite nano-intercalation material prepared in Preparation Example 4.

[0085] Example 5

[0086] A crack-resistant concrete reinforced truss floor deck is different from Example 1 in that 1 kg of sodium alginate solution with a mass concentration of 3% is further added to the raw materials of the crack-resistant concrete layer of this embodiment.

[0087] Example 6

[0088] A crack-resistant concrete reinforced truss floor deck is different from Example 1 in that 2 kg of sodium alginate solution with a mass concentration of 3% is further added to the raw materials of the crack-resistant concrete layer of this embodiment.

[0089] Example 7

[0090] A crack-resistant concrete reinforced truss floor deck is different from Example 1 in that 4 kg of sodium alginate solution with a mass concentration of 3% is further added to the raw materials of the crack-resistant concrete layer of this embodiment.

[0091] Comparative Example

[0092] Comparative Example 1

[0093] A crack-resistant concrete reinforced truss floor deck is different from Example 7 in that carbon nanotube-rectorite nano-intercalation material and CO2 curing powder are not added to the raw materials of the crack-resistant concrete layer of this comparative example, and machine-made sand is used instead.

[0094] Comparative Example 2

[0095] A crack-resistant concrete reinforced truss floor deck is different from Example 7 in that 4 kg of carbon nanotubes and 36 kg of rectorite powder are used in the raw materials of the crack-resistant concrete layer in this comparative example instead of carbon nanotube-rectorite nano-intercalation materials.

[0096] Comparative Example 3

[0097] A crack-resistant concrete reinforced truss floor deck is different from Example 7 in that CO2 curing powder is not added to the raw materials of the crack-resistant concrete layer of this comparative example, and machine-made sand is used instead.

[0098] Comparative Example 4

[0099] A crack-resistant concrete reinforced truss floor deck is different from Example 7 in that no β-alanine solution is added to the raw materials of the crack-resistant concrete layer of this comparative example, and the difference is replaced by water.

[0100] Performance testing

[0101] Test samples: From the anti-cracking concrete layer of the floor decking prepared in Examples 1-7 and Comparative Examples 1-4, respectively, cubic specimens with a side length of 150 mm were cut and made in accordance with the provisions of the "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" (GB / T50081-2019).

[0102] Test items:

[0103] 1. Compressive strength: A compression test was carried out using a pressure testing machine to determine the compressive strength. The results are shown in Table 2.

[0104] 2. Crack resistance: A hydraulic universal testing machine was used to measure the cracking load and crack width of the test samples. The results are shown in Table 2.

[0105] Table 2 Test results

[0106]

[0107] The compressive strengths of Examples 1-7 ranged from 75.6 to 82.8 MPa, all meeting high-strength concrete standards. Examples 5-7, in which sodium alginate solution was added, showed significant strength improvements (82.5 to 82.8 MPa), demonstrating that sodium alginate solution can further optimize compressive properties. In Examples 1-3, when the amount of intercalation material increased from 40 kg to 80 kg, the cracking load increased from 38.6 kN to 39.7 kN, and the crack width decreased from 0.16 mm to 0.13 mm. Because the intercalation material inhibits the crack propagation path through physical barriers and chemical bonding, it increases concrete toughness and effectively improves the crack resistance of the concrete layer. Example 4, using a single sulfuric acid acidification method, reduced the cracking load to 34.5 kN, a 10.6% decrease compared to Example 1. This demonstrates that mixed acid is beneficial for ensuring the intercalation of carbon nanotubes and rectorite, verifying the key role of the acidification process in material dispersibility and crack resistance.

[0108] After adding sodium alginate solution to Examples 5-7, the cracking load jumped to 43.2-43.6 kN, a 9.8%-10.1% increase compared to Example 3, and the crack width decreased to 0.07-0.08 mm. The three-dimensional gel network formed by sodium alginate physically blocks crack propagation and absorbs cracking energy through an energy dissipation mechanism, forming a multi-scale anti-crack system with the intercalation material and CO2-cured micropowder.

[0109] Comparative Example 1 lacks both the intercalation material and the CO2-cured powder, and the cracking load is only 23.5kN, and the crack width is 0.52mm, which are 46.1% and 500% lower than those in Example 7, respectively. This proves that the synergistic effect of the two is the core of the improved crack resistance: the intercalation material strengthens the interface transition zone, and the CO2-cured powder improves the matrix density. The two jointly inhibit the expansion of cracks from micro defects to macroscopic ones. Comparative Example 2 uses "carbon nanotubes + rectorite powder" to replace the intercalation material, and the cracking load is 30.6kN, which is 29.8% lower than that in Example 7. This shows that when the intercalation structure is not formed, the material has poor dispersion and low stress transfer efficiency, and the synergistic anti-cracking effect cannot be exerted. Comparative Example 3 does not add CO2-cured powder, and the cracking load is only 28.5kN, which is 34.6% lower than that in Example 7, and the crack width reaches 0.42mm. This demonstrates the effectiveness of CO2-cured powder in improving concrete crack resistance. The powder, treated with supercritical CO2, generates calcium carbonate crystals, which fill concrete pores and reduce stress concentration. Simultaneously, the active components of the waste residue are released, enhancing matrix compactness and thus inhibiting crack initiation. Comparative Example 4, which lacks β-alanine, exhibits a lower cracking load of 40.3 kN compared to Example 7. This demonstrates that β-alanine has a certain promoting effect on improving concrete crack resistance.

[0110] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A crack-resistant concrete reinforced truss floor deck, characterized in that: include: A steel truss and a crack-resistant concrete layer cast on the steel truss. The crack-resistant concrete layer comprises the following raw materials in parts by weight: 400-450 parts of cement, 80-120 parts of fly ash, 50-70 parts of slag powder, 650-800 parts of machine-made sand, 500-650 parts of crushed stone, 200-230 parts of water, 5-10 parts of a water reducer, 2-5 parts of a beta-alanine solution, 40-80 parts of a carbon nanotube-rectorite nano-intercalation material, and 60-100 parts of a CO2 curing fine powder. The carbon nanotube-rectorite nano-intercalation material is prepared by inserting acidified carbon nanotubes between sodium-based rectorite layers, and the CO2 curing fine powder is prepared by grinding industrial waste slag after supercritical CO2 treatment.

2. The crack-resistant concrete reinforced truss floor deck according to claim 1, characterized in that: The carbon nanotube-rectorite nano-intercalation material is prepared by the following method: (1) Reflux acidify multi-walled carbon nanotubes in mixed acid for 2-4 h, wash by centrifugation, and then dry naturally to obtain acidified carbon nanotubes. Disperse the acidified carbon nanotubes in deionized water and ultrasonicate for 30-60 min to obtain a carbon nanotube suspension. (2) Dispersing rectorite powder in carbon nanotube suspension and stirring for 2-4 hours, drying the mixture after stirring, placing the mixture in an internal mixer, setting the mixer temperature to 200-210 ° C, the rotor speed to 50-60 r / min, and the melt mixing time to 50-60 min. After the internal mixer is completed, the carbon nanotube-rectorite nano-intercalation material is obtained.

3. The crack-resistant concrete reinforced truss floor deck according to claim 2, characterized in that: In step (1), the mixed acid comprises sulfuric acid and nitric acid in a mass ratio of 1:(2-3); the mass fraction of the sulfuric acid is 65%-70%; and the mass fraction of the nitric acid is 65%-68%.

4. The crack-resistant concrete reinforced truss floor deck according to claim 3, characterized in that: In step (1), the mass ratio of multi-walled carbon nanotubes to mixed acid is 1:(10-15); the mass ratio of the acidified carbon nanotubes to deionized water is 1:(30-40).

5. The crack-resistant concrete reinforced truss floor deck according to claim 1, characterized in that: In step (2), the amount of rectorite powder used is 10-20 times the mass of the acidified carbon nanotubes.

6. The crack-resistant concrete reinforced steel truss floor deck according to claim 1, characterized in that: The CO2 curing micropowder is prepared by the following method: Crushing steel slag, blast furnace slag or slag to a particle size of 2-5 mm to obtain powder, adding the powder and grinding aid into a reactor, heating to 100-120 ° C, and then pumping CO2 into it until the pressure reaches 15-30 MPa, and then starting to stir for 4-6 hours, and finally obtaining CO2-cured micropowder after stirring.

7. The crack-resistant concrete reinforced steel truss floor deck according to claim 6, characterized in that: The grinding aid accounts for 0.5-1% of the powder, and the grinding aid is any one of sodium lignin sulfonate and triethanolamine.

8. The crack-resistant concrete reinforced steel truss floor deck according to claim 1, characterized in that: The concentration of the β-alanine solution is 40%-50%.

9. The crack-resistant concrete reinforced steel truss floor deck according to claim 1, characterized in that: The raw materials of the anti-cracking concrete layer also include 1-4 parts of sodium alginate solution.

10. The method for preparing a crack-resistant concrete reinforced truss floor deck according to claim 9, characterized in that: The steps include: S1. Tie the steel bars and corrugated steel plates according to the design requirements and weld them to form a steel truss; S2. Mix cement, fly ash, slag powder, machine-made sand, and crushed stone evenly, then add water, water reducer, polyvinyl alcohol solution, and sodium alginate solution and stir to form a uniform mixture, then add carbon nanotube-rectorite nano-intercalation material and CO2 curing powder and continue stirring to obtain crack-resistant concrete, pour the crack-resistant concrete on the steel truss, vibrate it with a vibrating device to make it dense, and then cure it for 18-24 hours to obtain the crack-resistant concrete steel truss floor deck.

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