A material for concrete floor deck

Abstract

The present invention belongs to the technical field of floor decking, and in particular to a material for concrete floor decking, wherein the material comprises 150-170 parts of cement, 30-35 parts of mineral admixture, 200-250 parts of sand, 100-120 parts of crushed stone, 40-45 parts of fiber, 5-10 parts of early strength agent, and 140-150 parts of water; the early strength agent comprises the following components in parts by weight: 20-30 parts of polycarboxylate water reducer, 5-10 parts of modified nano zeolite powder, 5-9 parts of lithium acetate, 3-5 parts of complexing agent, 5-10 parts of calcium sulfate, and 1-4 parts of diisopropanolamine. The present invention adds fiber, mineral admixture, and early strength agent to the formula, promotes early hydration of cement, avoids excessively fast hydration of cement in the later stage, causes shrinkage and cracking, effectively improves the compressive strength and flexural strength of the concrete floor deck, shortens the curing period of the concrete floor deck, and reduces production costs.

Description

Technical Field

[0001] The invention belongs to the technical field of floor decking, and in particular relates to a material for concrete floor decking. Background Art

[0002] In traditional construction, floor slab construction consumes significant manpower, material resources, and time, thus restricting the overall project progress. With the development of prefabricated composite slabs, the use of formwork has been reduced during floor slab construction, effectively improving construction efficiency. Currently, research on reinforced truss composite slabs is relatively mature and widely used.

[0003] Cement-based steel truss floor decking is a formwork material commonly used in building structures, capable of bearing loads, transmitting forces, and maintaining structural stability. It consists of a fiber-reinforced cement pressure plate with a pre-embedded galvanized steel grid in the center, a pre-embedded keel on the back, and steel trusses welded together to form an assembled formwork. By interacting with the concrete, it creates a structural system with high load-bearing capacity and rigidity. This type of floor decking features simple and intuitive load-bearing characteristics. During the construction phase, the steel trusses provide rigidity to the formwork and, together with the base formwork, bear the concrete's deadweight and construction loads. During the service phase, the steel bars serve as tension bars and, together with the concrete, bear the service loads. Therefore, the steel trusses require high flexural, compressive, impact, and tensile strengths.

[0004] The Chinese patent application document with publication number CN115974495A discloses a high performance concrete for composite board and its production method and composite board, wherein the weight ratio of the high performance concrete is kg / m 3 The composition of the composite board is as follows: 450-460 parts cement, 770-790 parts fly ash, 450-460 parts quartz sand, 9-11 parts water reducer, 300-305 parts water, and 15-17 parts fiber. This composite board is produced by mixing fibers with a specific ratio of cement, fly ash, quartz sand, water reducer, and water to create high-performance concrete, improving the concrete's inherent compressive, shear, and crack resistance. However, the document does not describe how to regulate the ratio of the raw materials to ensure the composite board's flexural and impact strengths. This composite board has a long setting time after forming, requiring a longer oxidation protection period, resulting in a longer production cycle, reduced production capacity, and increased production costs. Furthermore, the formula does not include coarse aggregate, consisting only of quartz sand, cement, and fly ash, resulting in lower flexural, compressive, and impact strengths. Summary of the Invention

[0005] In order to solve the technical problems of poor mechanical properties, long maintenance period and high production cost of concrete floor decking in the above-mentioned prior art, the present invention provides a material for concrete floor decking.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A material for concrete floor slabs, comprising the following components in parts by weight:

[0008] 150-170 parts of cement, 30-35 parts of mineral admixture, 200-250 parts of sand, 100-120 parts of crushed stone, 40-45 parts of fiber, 5-10 parts of early strength agent, and 140-150 parts of water; the early strength agent includes the following components in parts by weight: 20-30 parts of polycarboxylate water reducer, 5-10 parts of modified nano zeolite powder, 5-9 parts of lithium acetate, 3-5 parts of complexing agent, 5-10 parts of calcium sulfate, and 1-4 parts of diisopropanolamine.

[0009] In the above technical solution, the early strength of cement-based materials is improved by adding an early strength agent to the concrete floor slab material, effectively shortening the production cycle. Among them, nano zeolite has a porous structure and a high specific surface area, can react with cement hydration products to generate stable gelled products, has a good promoting effect on cement hydration, and can more effectively and quickly absorb the calcium hydroxide enriched on the interface, greatly reducing the orientation degree of calcium hydroxide on the interface, can significantly improve the early and late strength of concrete, and make its microstructure more dense, and significantly improve the durability of concrete. Lithium acetate can release lithium ions and hydroxide ions during the cement hydration process, thereby increasing the alkalinity of the system, which is conducive to promoting the dissolution of active silicate in fly ash, making the glassy components in fly ash more likely to break, releasing more active components to participate in the hydration process, and at the same time, the lithium hydroxide generated by lithium acetate during the hydrolysis process provides nucleation sites for cement hydration, accelerating the cement hydration rate. However, the addition of lithium acetate promotes the conversion of ettringite to monosulfur-type calcium sulfoaluminate hydrate, weakening the skeleton function of ettringite and resulting in a decrease in the strength of cement-based materials. The present invention adds calcium sulfate to the early strength agent formula. Calcium sulfate can provide sulfate ions and calcium ions for cement hydration. During the cement hydration process, tricalcium aluminate can react rapidly on the outside of the cement gelling membrane to form ettringite, which plays a skeleton role in the early stages of cement hydration and improves the early strength of cement-based materials. Therefore, the use of lithium acetate and calcium sulfate together in the present invention can effectively ensure that the mechanical properties of cement-based materials are significantly improved in the early stages.

[0010] In addition, the present invention controls the compressive strength and brittleness of concrete floor deck materials by controlling the content of cementitious materials in the material formula. Studies have found that with the increase in the amount of cement and mineral admixtures in the concrete floor deck materials, the compressive strength increases, but the brittleness also increases and the flexural strength decreases. Therefore, the present invention adds fibers and early strength agents to the formula. On the one hand, the polycarboxylic acid water-reducing agent in the early strength agent is used to reduce the water-cement ratio, so that the cementitious material is hydrated more fully, forming a denser structure, and jointly improving the flexural strength with the fiber. On the other hand, the early strength agent is used to promote the early hydration process of cement, effectively improve the early strength, avoid shrinkage and cracking caused by excessive hydration and excessive heat release of cement in the later stage, and further improve the flexural strength.

[0011] Furthermore, the preparation method of the polycarboxylate water reducer is as follows: add isopentanol polyoxyethylene ether and deionized water to a reactor, stir and dissolve, add methacrylic acid and ammonium persulfate, heat to 70-80°C, and simultaneously dropwise add a mixed aqueous solution of hydrogen peroxide, acrylic acid, mercaptopropionic acid, diethyl acrylate phosphate, and N-vinylacetamide, control the dropwise addition time to be 2-2.4h, keep the temperature for reaction for 1-1.5h after the dropwise addition is completed, adjust the pH to neutral, and obtain the polycarboxylate water reducer.

[0012] The polycarboxylate water-reducing agent prepared by the above technical solution has a linear main chain of polyethylene and a long side chain of polyoxyethylene. Short side chains containing phosphate groups, amide groups, and ester groups are interspersed in the long side chains. These long and short side chains are arranged in a staggered manner, so that the polycarboxylate water-reducing agent has high dispersibility and effectively reduces the water-cement ratio of cement-based materials. The phosphate groups in the molecular side chains can form stable complexes with calcium ions in cement. The amide groups accelerate the formation of ettringite by interacting with tricalcium aluminate in cement. The carboxyl groups after hydrolysis of the ester groups can be secondary adsorbed on cement particles, effectively improving the dispersibility of cement particles, reducing the viscosity of the cement system, and improving the mechanical properties of cement-based materials.

[0013] In the above technical solution, before the reaction starts, adding a small amount of methacrylic acid can keep the reaction rate of the initial polymerization reaction stable and avoid the phenomenon of uneven molecular side chain arrangement caused by excessive polymerization; the dropwise addition of mercaptopropionic acid together with acrylic acid can effectively ensure that the polycarboxylic acid water-reducing agent molecules obtained by polymerization have a shorter main chain, which is beneficial to improving the dispersibility of the polycarboxylic acid water-reducing agent; the dropwise addition of an aqueous solution of acrylic acid, diethyl phosphate acrylate and N-vinylacetamide can effectively ensure the uniformity of the side chain arrangement of the polycarboxylic acid water-reducing agent molecules.

[0014] Furthermore, the mass parts of each component in the preparation method of the polycarboxylate water reducer are: 50-60 parts of isopentanol polyoxyethylene ether, 100-120 parts of deionized water, 5-8 parts of methacrylic acid, 5-8 parts of ammonium persulfate, 5-9 parts of hydrogen peroxide, 10-13 parts of acrylic acid, 3-5 parts of mercaptopropionic acid, 9-13 parts of diethyl acrylate phosphate, and 12-15 parts of N-vinylacetamide.

[0015] Furthermore, the relative molecular mass of the isopentenol polyoxyethylene ether is 2400.

[0016] Furthermore, the preparation method of the modified nano zeolite powder is as follows: adding the nano zeolite powder to vinyltriethoxysilane, heating to 60-65°C and stirring for 2.5-3 hours, then heating to 85-90°C, keeping the temperature for reaction for 4-5 hours, cooling and filtering to obtain a powder material; adding the powder material, hydrogen peroxide, 2-acrylamide-2-methylpropanesulfonic acid and deionized water I to a reactor, heating to 70-75°C, adding a mixed solution of mercaptoethanol, L-ascorbic acid and deionized water II dropwise under stirring, keeping the temperature for reaction for 1.5-2 hours, cooling, and filtering to obtain the modified nano zeolite.

[0017] In the above technical solution, the nano-zeolite powder is first modified with a silane coupling agent to obtain a nano-zeolite powder with a double bond, which is then grafted with 2-acrylamide-2-propanesulfonic acid to obtain a modified nano-zeolite powder with an amide group and a sulfonic acid group. The molecular chains grafted on its surface overcome the van der Waals force between the nanoparticles, effectively improving the dispersibility of the nano-zeolite powder in cement-based materials. At the same time, the amide groups contained in the grafted molecular chains promote the formation of Ca(OH)2, and the sulfonic acid groups can promote the hydration of dicalcium silicate and significantly increase the early hydration heat release, thereby improving the mechanical properties of the cement-based material.

[0018] Furthermore, the weight proportions of the components in the preparation method of the modified nano zeolite powder are: 20-30 parts of nano zeolite powder, 30-40 parts of vinyltriethoxysilane, 2-5 parts of hydrogen peroxide, 10-15 parts of 2-acrylamide-2-methylpropanesulfonic acid, 25-30 parts of deionized water I, 1-3 parts of mercaptoethanol, 3-5 parts of L-ascorbic acid, and 30-40 parts of deionized water II.

[0019] Furthermore, the complexing agent is composed of ethylenediaminetetraacetic acid and citric acid in a mass ratio of 5-9:2-4.

[0020] Ethylenediaminetetraacetic acid can form a stable complex with the calcium ions in calcium sulfate. At the same time, its multi-carboxyl structure can also interact with the carboxyl groups of polycarboxylate superplasticizers. Citric acid has multiple carboxyl groups and can form a complex with calcium ions. It can also interact with the ether groups of polycarboxylate superplasticizers, thereby improving the compatibility of calcium sulfate and polycarboxylate superplasticizers and avoiding the uneven dispersion of calcium sulfate that affects the early strength performance.

[0021] Furthermore, the mineral admixture is composed of fly ash, silica fume and slag powder in a mass ratio of 4-7:2-5:9-11.

[0022] Fly ash is a material with potential pozzolanic activity. Under the action of an early strength agent, the active ingredients in fly ash can rapidly react with the calcium hydroxide produced by cement hydration to form hydrated calcium silicate gel and ettringite, among other hydration products. These products fill the pores of the cement-based material, increasing its density and, in turn, its compressive and flexural strengths. However, when the fly ash dosage exceeds the limits set forth in the present invention, the compressive strength of the cement-based material decreases. This is because when the fly ash dosage is too high, the hydrated calcium silicate gel produced by the reaction is insufficient to compensate for the dilution effect caused by the fly ash, resulting in a decrease in the compressive strength of the cement-based material. Silica fume has a high pozzolanic activity and can not only react with the calcium hydroxide produced by cement hydration to form hydrated calcium silicate gel, but its high activity also accelerates the cement hydration reaction and fills the tiny pores between cement particles, increasing the density of the cement-based material and, thus, improving its mechanical properties. Slag powder will undergo a secondary hydration reaction during the cement hydration process. This reaction is relatively slow in the early stages, but over time, the slag powder gradually reacts with the calcium hydroxide in the cement hydration products to form hydrated calcium silicate gel. These gels can fill the pores of cement-based materials and improve the density and later strength of cement-based materials.

[0023] Furthermore, the cement is silicate cement with a strength grade of P.O42.5 and an apparent density of 3.10 g / cm 3 The sand is composed of coarse sand with a fineness modulus of 3.7-3.1 and medium sand with a fineness modulus of 3.0-2.3 in a mass ratio of 1:1; the crushed stone is 5-25mm continuously graded crushed stone with an apparent density of 2850kg / m 3 .

[0024] Furthermore, the fiber is one of polyacrylonitrile fiber, polyester fiber and carbon fiber.

[0025] Compared with the existing technology, the concrete floor slab material provided by the present invention has the following technical advantages:

[0026] (1) The present invention adds fiber and early strength agent to the formula to promote early hydration of cement, avoid excessive hydration of cement in the later stage leading to shrinkage and cracking, and together with the fiber, improve the compressive strength and flexural strength of the floor deck;

[0027] (2) The present invention effectively improves the early strength of the concrete floor slab by adding mineral admixtures and early strength agents to the formula, shortens the production cycle, and reduces production costs;

[0028] (3) The material formula for the concrete floor slab provided by the present invention is simple and the raw materials are easily available, which is conducive to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the scanning electron microscope image of the concrete specimen of the blank control group 1 day;

[0030] Figure 2 This is a scanning electron microscope image of the concrete specimen of group 1d in Example 3;

[0031] Figure 3 This is the scanning electron microscope image of the 7-day concrete specimen of the blank control group;

[0032] Figure 4 This is a scanning electron microscope image of the 7d concrete specimens of Example 3. DETAILED DESCRIPTION

[0033] The following will be further described in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Those skilled in the art may make various modifications based on the basic concept of the present invention, but as long as they do not depart from the basic concept of the present invention, they are all within the scope of the present invention.

[0034] The cement in this embodiment is silicate cement with a strength grade of P.O42.5 and an apparent density of 3.10 g / cm 3 The sand is composed of coarse sand with a fineness modulus of 3.7-3.1 and medium sand with a fineness modulus of 3.0-2.3 in a mass ratio of 1:1; the gravel is 5-25mm continuously graded gravel with an apparent density of 2850kg / m 3 The fly ash is Class F II fly ash with a density of 2150kg / m 3 The silica fume is grade 90 silica fume with a density of 180kg / m 3 The slag powder is S95 grade slag powder with a density of 2880kg / m 3 .

[0035] In this specific embodiment, the relative molecular mass of the isopentenol polyoxyethylene ether is 2400.

[0036] Example 1

[0037] A material for concrete floor slabs, comprising the following components in parts by weight:

[0038] 150g cement, 30g mineral admixture, 200g sand, 100g crushed stone, 40g polyacrylonitrile fiber, 5g early strength agent, 150g water; the mineral admixture is composed of fly ash, silica fume and slag powder in a mass ratio of 4:2:9.

[0039] The early strength agent includes the following components in parts by weight: 20g of polycarboxylate water reducer, 10g of modified nano zeolite powder, 9g of lithium acetate, 5g of complexing agent, 10g of calcium sulfate, and 4g of diisopropanolamine; the complexing agent is composed of ethylenediaminetetraacetic acid and citric acid in a mass ratio of 5:2.

[0040] The preparation method of the polycarboxylate water reducer comprises the following steps: adding 50 g of isopentanol polyoxyethylene ether and 100 g of deionized water into a reaction kettle, stirring and dissolving the mixture, adding 5 g of methacrylic acid and 5 g of ammonium persulfate, heating the mixture to 70° C., and simultaneously dropwise adding a mixed aqueous solution of 5 g of hydrogen peroxide, 10 g of acrylic acid, 3 g of mercaptopropionic acid, 9 g of diethyl acrylate phosphate, and 12 g of N-vinyl acetamide, wherein the dropwise addition time is controlled to be 2 h. After the dropwise addition is completed, the mixture is kept warm for reaction for 1 h, and the pH is adjusted to neutral to obtain the polycarboxylate water reducer.

[0041] The modified nano-zeolite powder is prepared by adding 20 g of nano-zeolite powder to 30 g of vinyltriethoxysilane, heating to 60° C. and stirring for 2.5 hours, then heating to 85° C., keeping the temperature for reaction for 4 hours, cooling, and filtering to obtain a powder material; adding the powder material, 2 g of hydrogen peroxide, 10 g of 2-acrylamide-2-methylpropanesulfonic acid, and 25 g of deionized water to a reactor, heating to 70° C., and dropwise adding a mixed solution of 1 g of mercaptoethanol, 3 g of L-ascorbic acid, and 30 g of deionized water while stirring, keeping the temperature for reaction for 1.5 hours, cooling, and filtering to obtain the modified nano-zeolite.

[0042] Example 2

[0043] A material for concrete floor slabs, comprising the following components in parts by weight:

[0044] 170g cement, 35g mineral admixture, 250g sand, 120g crushed stone, 45g polyester fiber, 10g early strength agent, 140g water; the mineral admixture is composed of fly ash, silica fume and slag powder in a mass ratio of 7:5:11.

[0045] The early strength agent includes the following components in parts by weight: 30g of polycarboxylic acid water reducer, 5g of modified nano zeolite powder, 5g of lithium acetate, 3g of complexing agent, 5g of calcium sulfate, and 1g of diisopropanolamine; the complexing agent is composed of ethylenediaminetetraacetic acid and citric acid in a mass ratio of 9:4.

[0046] The preparation method of the polycarboxylate water reducer comprises the following steps: adding 60 g of isopentanol polyoxyethylene ether and 120 g of deionized water into a reactor, stirring and dissolving them, adding 8 g of methacrylic acid and 8 g of ammonium persulfate, heating the reactor to 80° C., and simultaneously dropwise adding a mixed aqueous solution of 9 g of hydrogen peroxide, 13 g of acrylic acid, 5 g of mercaptopropionic acid, 13 g of diethyl acrylate phosphate, and 15 g of N-vinyl acetamide, controlling the dropwise addition time to be 2.4 h, and maintaining the reaction temperature for 1.5 h after the dropwise addition is completed, adjusting the pH to neutral, and thereby obtaining the polycarboxylate water reducer.

[0047] The modified nano-zeolite powder is prepared by adding 30 g of nano-zeolite powder to 40 g of vinyltriethoxysilane, heating to 65° C. and stirring for 3 hours, then heating to 90° C., keeping the temperature for reaction for 5 hours, cooling, and filtering to obtain a powder material; adding the powder material, 5 g of hydrogen peroxide, 15 g of 2-acrylamide-2-methylpropanesulfonic acid, and 30 g of deionized water to a reactor, heating to 75° C., and dropwise adding a mixed solution of 3 g of mercaptoethanol, 5 g of L-ascorbic acid, and 40 g of deionized water under stirring, keeping the temperature for reaction for 2 hours, cooling, and filtering to obtain the modified nano-zeolite.

[0048] Example 3

[0049] A material for concrete floor slabs, comprising the following components in parts by weight:

[0050] 160g cement, 32g mineral admixture, 240g sand, 110g crushed stone, 43g carbon fiber, 8g early strength agent, 145g water; the mineral admixture is composed of fly ash, silica fume and slag powder in a mass ratio of 5:4:10.

[0051] The early strength agent includes the following components in parts by weight: 26g of polycarboxylic acid water reducer, 8g of modified nano zeolite powder, 8g of lithium acetate, 4g of complexing agent, 7g of calcium sulfate, and 3g of diisopropanolamine; the complexing agent is composed of ethylenediaminetetraacetic acid and citric acid in a mass ratio of 7:3.

[0052] The preparation method of the polycarboxylate water reducer comprises the following steps: adding 56 g of isopentanol polyoxyethylene ether and 110 g of deionized water into a reaction kettle, stirring and dissolving them, adding 7 g of methacrylic acid and 7 g of ammonium persulfate, heating the kettle to 75° C., and simultaneously dropwise adding a mixed aqueous solution of 8 g of hydrogen peroxide, 12 g of acrylic acid, 4 g of mercaptopropionic acid, 11 g of diethyl acrylate phosphate, and 14 g of N-vinyl acetamide, controlling the dropwise addition time to be 2.2 h, and maintaining the temperature for reaction for 1.3 h after the dropwise addition is completed, adjusting the pH to neutral, and thereby obtaining the polycarboxylate water reducer.

[0053] The modified nano-zeolite powder is prepared by adding 27 g of nano-zeolite powder to 36 g of vinyltriethoxysilane, heating the mixture to 63° C. and stirring for 2.8 hours, then heating the mixture to 88° C., keeping the mixture warm for 4.5 hours, cooling the mixture, and filtering the mixture to obtain a powder. The powder, 4 g of hydrogen peroxide, 13 g of 2-acrylamide-2-methylpropanesulfonic acid, and 28 g of deionized water are added to a reactor, heating the mixture to 74° C., and dropping a mixed solution of 2 g of mercaptoethanol, 4 g of L-ascorbic acid, and 35 g of deionized water while stirring the mixture. The mixture is kept warm for 1.8 hours, cooled, and filtered to obtain the modified nano-zeolite.

[0054] Comparative Example 1

[0055] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of calcium sulfate is used instead of lithium acetate in the early strength agent in this comparative example.

[0056] Comparative Example 2

[0057] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of lithium acetate is used instead of calcium sulfate in the early strength agent in this comparative example.

[0058] Comparative Example 3

[0059] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that methacrylic acid is not added in the preparation method of the polycarboxylate water-reducing agent in this comparative example.

[0060] Comparative Example 4

[0061] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of N-vinylacetamide is used instead of diethyl acrylate in the preparation method of the polycarboxylate water-reducing agent in this comparative example.

[0062] Comparative Example 5

[0063] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that this comparative example uses an equal amount of nano zeolite powder instead of modified nano zeolite powder.

[0064] Comparative Example 6

[0065] The materials used for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of deionized water is used instead of 2-acrylamide-2-methylpropanesulfonic acid in the preparation method of the modified nano-zeolite powder in this comparative example.

[0066] Comparative Example 7

[0067] The materials for the concrete floor slab in this comparative example are similar to those in Example 3. The difference between this comparative example and Example 3 is that an equal amount of acrylamide is used instead of 2-acrylamide-2-methylpropanesulfonic acid in the preparation method of the modified nano-zeolite powder in this comparative example.

[0068] Test example

[0069] Test samples: The concrete floor deck materials provided in Examples 1 to 3 and Comparative Examples 1 to 7 were mixed evenly and poured into a 75×75×285 mold. After vibrating, the mixture was cured for 1 day and then demolded. After demolding, the mixture was further cured to obtain test specimens. No early strength agent was added in Comparative Example 1, and no mineral admixture was added in Comparative Example 2.

[0070] Test method: According to GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete", the compressive strength and flexural strength of test specimens cured to 1d, 7d, and 28d were tested.

[0071] The test results are shown in Table 1.

[0072] Table 1 Mechanical properties test results

[0073]

[0074] As can be seen from Table 1, the compressive strength of the concrete floor deck material provided by the present invention at 1d is 32.9-34.2 MPa, the compressive strength at 7d is 68.5-69.7 MPa, and the compressive strength at 28d is 80.3-83.2 MPa; the flexural strength at 1d is 7.5-8.3 MPa, the flexural strength at 3d is 12.1-12.9 MPa, and the flexural strength at 28d is 15.2-16.5 MPa. Compared with the control example, the compressive strength and flexural strength of the concrete floor deck materials provided by Examples 1 to 3 of the present invention are improved to a certain extent, which indicates that the concrete floor deck material provided by the present invention has good mechanical properties.

[0075] Compared with Example 3, in Comparative Example 1, an equal amount of calcium sulfate was used instead of lithium acetate in the early strength agent, and the 1d and 7d compressive strength and flexural strength of the prepared concrete test block increased, indicating that calcium sulfate can promote the increase of early compressive and flexural strength, and the 28d compressive strength and flexural strength decreased, indicating that lithium acetate can effectively promote the release of active components of fly ash to participate in the hydration process, and the enhancing effect of calcium sulfate on the mechanical properties of cement-based materials is weaker than the enhancing effect of hydration of active components of fly ash on the mechanical properties of cement-based materials; in Comparative Example 2, an equal amount of lithium acetate was used instead of calcium sulfate in the early strength agent, and the prepared concrete The compressive strength and flexural strength of the test blocks were reduced to varying degrees, which shows that excessive use of lithium acetate will weaken the skeleton effect of ettringite, while the addition of calcium sulfate can effectively improve the mechanical properties of the concrete test blocks; in the preparation method of the polycarboxylate water-reducing agent in Comparative Example 3, methacrylic acid was not added, and the compressive strength and flexural strength of the prepared concrete test blocks 1d and 7d were reduced. This is because the uneven arrangement of the molecular side chains of the polycarboxylate water-reducing agent leads to poor dispersibility of the polycarboxylate water-reducing agent in cement, which affects the early hydration process of the cement; in the preparation method of the polycarboxylate water-reducing agent in Comparative Example 4, an equal amount of N-vinyl acetamide is used instead of The compressive strength and flexural strength of the concrete specimens prepared by adding diethyl acrylate phosphate were reduced at 1d and 7d, which shows that the phosphate group and ester group in the side chain of the polycarboxylate water-reducing agent molecule can effectively improve the mechanical properties of the concrete specimens; in Comparative Example 5, the nano zeolite powder was not modified, and the compressive strength and flexural strength of the concrete specimens prepared were reduced. This is due to the uneven distribution of the unmodified zeolite powder in the concrete specimens; in the preparation method of the modified nano zeolite powder in Comparative Example 6, an equal amount of deionized water was used instead of 2-acrylamide-2-methylpropanesulfonic acid, and the preparation method of the modified nano zeolite powder in Comparative Example 7 was In the preparation method, an equal amount of acrylamide was used instead of 2-acrylamide-2-methylpropanesulfonic acid. The 1d and 7d compressive strengths and flexural strengths of the prepared concrete specimens were reduced, and the 28d compressive strength and flexural strength were slightly reduced. This shows that the use of 2-acrylamide-2-methylpropanesulfonic acid in the present invention to graft the nano-zeolite powder modified with the silane coupling agent can effectively improve the early strength of the concrete specimen and further improve the dispersibility of the modified nano-zeolite powder in the concrete specimen, while the effect of grafting acrylamide is obviously not as good as that of grafting 2-acrylamide-2-methylpropanesulfonic acid.

[0076] The present invention also conducted scanning electron microscopy tests on the concrete test blocks of Example 3 and the blank control group at 1 day and 7 days. The preparation method of the concrete test blocks of the blank control group is similar to that of Example 3. The difference between the blank control group and Example 3 is that no early strength agent was added to the blank control group. The test results are as follows: Figure 1-Figure 4 .

[0077] Depend on Figure 1 and Figure 2It can be seen that compared with the blank control group, more calcium silicate hydrate and ettringite appeared in the concrete after adding the early strength agent at the age of 1 day, and they were more densely packed. Figure 3 and Figure 4 It can be seen that compared with the blank control group, the grain distribution of the concrete specimens after adding the early strength agent is more uniform, and the grains grow into clusters. This shows that the early strength agent provided by the present invention can not only promote the early hydration process of cement, but also refine the grains, improve the density of concrete, and thus enhance the mechanical properties of concrete.

[0078] The above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Persons skilled in the art should not modify the above embodiments without departing from the spirit and scope of the present invention. Any equivalent modifications or alterations made by persons skilled in the art without departing from the technical spirit of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A material for concrete floor slabs, characterized in that: The composition comprises the following components in parts by weight: 150-170 parts of cement, 30-35 parts of mineral admixture, 200-250 parts of sand, 100-120 parts of crushed stone, 40-45 parts of fiber, 5-10 parts of early strength agent, and 140-150 parts of water; the early strength agent includes the following components in parts by weight: 20-30 parts of polycarboxylate water reducer, 5-10 parts of modified nano zeolite powder, 5-9 parts of lithium acetate, 3-5 parts of complexing agent, 5-10 parts of calcium sulfate, and 1-4 parts of diisopropanolamine; The modified nano-zeolite powder is prepared by adding the nano-zeolite powder to vinyltriethoxysilane, heating the mixture to 60-65° C. and stirring for 2.5-3 hours, then heating the mixture to 85-90° C., keeping the mixture warm for 4-5 hours, cooling the mixture, and filtering the mixture to obtain a powder. The powder, hydrogen peroxide, 2-acrylamide-2-methylpropanesulfonic acid, and deionized water (I) are added to a reactor, heated to 70-75° C., and a mixed solution of mercaptoethanol, L-ascorbic acid, and deionized water (II) is added dropwise while stirring. The mixture is kept warm for 1.5-2 hours, cooled, and filtered to obtain the modified nano-zeolite.

2. The concrete floor deck material according to claim 1, characterized in that: The preparation method of the polycarboxylate water reducer comprises the following steps: adding isopentanol polyoxyethylene ether and deionized water into a reaction kettle, stirring and dissolving them, adding methacrylic acid and ammonium persulfate, raising the temperature to 70-80° C., and simultaneously dropwise adding a mixed aqueous solution of hydrogen peroxide, acrylic acid, mercaptopropionic acid, diethyl acrylate phosphate, and N-vinylacetamide, controlling the dropwise addition time to be 2-2.4 hours, and after the dropwise addition is completed, keeping the temperature for reaction for 1-1.5 hours, and adjusting the pH value to neutral to obtain the polycarboxylate water reducer.

3. The concrete floor deck material according to claim 2, characterized in that: The mass parts of each component in the preparation method of the polycarboxylate water reducer are: 50-60 parts of isopentanol polyoxyethylene ether, 100-120 parts of deionized water, 5-8 parts of methacrylic acid, 5-8 parts of ammonium persulfate, 5-9 parts of hydrogen peroxide, 10-13 parts of acrylic acid, 3-5 parts of mercaptopropionic acid, 9-13 parts of diethyl acrylate phosphate, and 12-15 parts of N-vinylacetamide.

4. The concrete floor deck material according to claim 2, characterized in that: The relative molecular mass of the isopentenol polyoxyethylene ether is 2400.

5. The concrete floor deck material according to claim 1, characterized in that: The weight proportions of the components in the preparation method of the modified nano-zeolite powder are as follows: 20-30 parts of nano-zeolite powder, 30-40 parts of vinyltriethoxysilane, 2-5 parts of hydrogen peroxide, 10-15 parts of 2-acrylamide-2-methylpropanesulfonic acid, 25-30 parts of deionized water I, 1-3 parts of mercaptoethanol, 3-5 parts of L-ascorbic acid, and 30-40 parts of deionized water II.

6. The concrete floor deck material according to claim 1, characterized in that: The complexing agent is composed of ethylenediaminetetraacetic acid and citric acid in a mass ratio of 5-9:2-4.

7. The concrete floor deck material according to claim 1, characterized in that: The mineral admixture is composed of fly ash, silica fume and slag powder in a mass ratio of 4-7:2-5:9-11.

8. The material for concrete floor decking according to claim 1, characterized in that: The cement is silicate cement with a strength grade of P.O42.5 and an apparent density of 3.10 g / cm 3 The sand is composed of coarse sand with a fineness modulus of 3.7-3.1 and medium sand with a fineness modulus of 3.0-2.3 in a mass ratio of 1:1; the crushed stone is 5-25mm continuously graded crushed stone with an apparent density of 2850kg / m 3 .

9. The concrete floor deck material according to claim 1, characterized in that: The fiber is one of polyacrylonitrile fiber, polyester fiber and carbon fiber.

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