A multi-component concrete based on Portland cement and its preparation method

Abstract

The present invention relates to the technical field of building materials, and discloses a multi-component concrete based on portland cement and a preparation method thereof. The multi-component concrete is formed by using portland cement as the base material and fly ash, fiber materials, etc. as auxiliary materials through mixing. By using a polymeric macromolecular modifier to modify aluminum silicate fibers, a large number of molecular chains of the polymeric macromolecular modifier are coated on the surface of the aluminum silicate fibers, so that the prepared fiber material as a whole presents a micro dendritic three-dimensional structure. When mixing with base materials such as cement, these dendritic micro three-dimensional structures will extend to various regions of the cement matrix to form a "mortise and tenon" structure, and then firmly embed into the concrete structure, thereby efficiently exerting its own strengthening effect and improving the mechanical strength and crack resistance of the concrete, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to a multi-component concrete based on portland cement and a preparation method thereof. Background Art

[0002] Concrete, as an indispensable material in modern architecture, has experienced a development process from traditional single-component to modern multi-component. With the progress of technology and the diversification of engineering requirements, multi-component concrete has gradually become the preferred material in the construction industry. Generally speaking, the basic composition of concrete includes four basic elements: cement, sand, stone, and water. However, in practice, in order to further optimize the specific properties of concrete, such as enhancing its fluidity, increasing strength, or improving durability, appropriate amounts of admixtures and mineral admixtures, such as fibers, are often incorporated according to needs.

[0003] The invention patent with the publication number CN116102319B discloses a composite fiber-reinforced concrete and a preparation method thereof. By mixing modified bamboo fibers, carbon fibers, and basalt fibers to form composite fibers and using them as additives to enhance and modify concrete, the mechanical strength of concrete can be improved. However, the specific surface area of fibers is relatively large, which easily leads to a deterioration in the fluidity of concrete. Moreover, the interfacial bonding performance between fibers and concrete is poor, and large gaps are easily formed between them, resulting in an insufficiently dense structure of the hardened concrete and an inability to achieve a good strengthening effect. Therefore, it is necessary to modify the fibers to enhance their adhesion to other components in the concrete in order to efficiently exert the strengthening effect of the fibers themselves. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide a multi-component concrete based on portland cement and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A preparation method of a multi-component concrete based on portland cement, wherein the multi-component concrete comprises the following raw materials in parts by weight:

[0007] Portland cement 45 - 50 parts;

[0008] Fly ash 5 - 8 parts;

[0009] Fiber material 4 - 10 parts;

[0010] Aggregate 50 - 60 parts;

[0011] Aggregating material 30 - 36 parts;

[0012] Water reducing agent 2 - 4 parts;

[0013] 40 - 60 parts of water;

[0014] The preparation method includes the following steps:

[0015] First step, prepare all raw materials according to the weight parts;

[0016] Second step, at a stirring rate of 500 - 1000 r / min, place Portland cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir evenly. Then adjust the stirring rate to 300 - 500 r / min, continue to add water reducing agent and water and stir. After 10 - 20 min, it is ready.

[0017] As a further solution of the present invention, the Portland cement is 42.5R type ordinary Portland cement or 52.5R type ordinary Portland cement; the fly ash is grade I fly ash or grade II fly ash; the aggregate is fine stone with a particle size ≤ 10 mm; the aggregate is river sand with a particle size ≤ 5 mm; the water reducing agent is naphthalene series water reducing agent or polycarboxylate water reducing agent.

[0018] As a further solution of the present invention, the preparation method of the fiber material specifically includes the following steps:

[0019] Step 1, disperse aluminum silicate fiber in toluene to form a dispersion liquid. Then add diisocyanate monomer and tin catalyst to the dispersion liquid. After adding, raise the temperature to 70 - 80 °C and keep it at this temperature for 4 - 6 h. Then separate the fiber material to obtain modified aluminum silicate fiber;

[0020] Step 2, add polymeric macromolecule modifier to N,N - dimethylformamide, stir evenly by mechanical stirring, add modified aluminum silicate fiber, disperse ultrasonically for 20 - 30 min. Then raise the temperature to 60 - 70 °C and keep it for 8 - 12 h. Then separate the product to obtain the fiber material.

[0021] As a further solution of the present invention, in step 1, the tin catalyst is any one of dibutyltin diacetate, stannous octoate or dibutyltin dilaurate.

[0022] As a further solution of the present invention, in step 1, the diisocyanate monomer is any one of isophorone diisocyanate, toluene diisocyanate or diphenylmethane - 4,4’ - diisocyanate.

[0023] As a further solution of the present invention, in step 2, the preparation method of the polymeric macromolecule modifier is specifically as follows:

[0024] Add 4,4'-diaminostilbene-2,2'-disulfonic acid and 2,3-dibromosuccinic acid to 1,4-dioxane, start stirring until a homogeneous reaction solution is formed, introduce nitrogen to expel air, then start the heating program, control the heating rate at 3-5 °C / min, raise the temperature to 70-80 °C, keep stirring for 6-9 h, then lower the temperature to 50-60 °C, add an acid acceptor to the reaction solution, after adding, continue to keep stirring for 4-8 h, evaporate to remove the solvent, collect the product, and a polymeric macromolecular modifier can be obtained.

[0025] As a further scheme of the present invention, the molar ratio of 4,4'-diaminostilbene-2,2'-disulfonic acid to 2,3-dibromosuccinic acid is 1-1.2:1.

[0026] As a further scheme of the present invention, the acid acceptor is an aqueous solution of an alkaline hydroxide with a mass fraction of 20-30%.

[0027] As a further scheme of the present invention, the alkaline hydroxide is potassium hydroxide or sodium hydroxide.

[0028] A multi-component concrete based on portland cement is prepared by the above preparation method.

[0029] Advantages of the present invention:

[0030] In the present invention, by incorporating additive components such as fly ash and fiber materials into portland cement in the form of physical mixing, and at the same time, by reasonably controlling the composition adjustment of each additive component, the formula is more optimized, and the defect of easily generating a large number of pores during the cement coagulation and forming process can be eliminated. Among them, the addition of fly ash can save costs. The fiber material can utilize the characteristics of its own fibers to enhance the connection effect between portland cement and other additive components, which is beneficial to making the internal structure of the concrete body more dense, thereby improving the mechanical strength and crack resistance of the concrete. By controlling the ratio of aggregate and aggregate, the rheological properties of the concrete are improved, which is beneficial to enhancing the overall strength of the concrete. Brief Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 It is an infrared analysis test chart of a polymeric macromolecular modifier. Detailed Embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0034] Preparation Example

[0035] Preparation of fiber material:

[0036] Step 1: Disperse 3.5 g of aluminosilicate fiber in toluene to form a dispersion liquid. Then, add 5 g of diphenylmethane-4,4'-diisocyanate and 0.1 g of stannous octoate to the dispersion liquid. After adding, raise the temperature to 75 °C and keep it at this temperature for 4 h. Then, separate the fiber material to obtain modified aluminosilicate fiber.

[0037] According to the titration test method, test the percentage content of isocyanate groups in the modified aluminosilicate fiber. The specific test method is the hydrochloric acid-dibutylamine test method. Use 0.2 g of the modified aluminosilicate fiber as the titration sample and use hydrochloric acid with a concentration of 0.1 mol / L as the standard solution. The test results show that the percentage content of isocyanate groups is 6.422%.

[0038] Step 2: Add 6.5 g of polymeric macromolecular modifier to N,N-dimethylformamide. After mechanical stirring and mixing, add 3.2 g of modified aluminosilicate fiber and ultrasonically disperse for 30 min. Then, raise the temperature to 65 °C and keep it for 9 h. Then, separate the product to obtain the fiber material.

[0039] Perform the hydrochloric acid-dibutylamine titration test on the fiber material again. The measured percentage content of isocyanate groups is 1.184%. It can be speculated that the principle of the above technical solution is as follows: First, under the action of the tin catalyst stannous octoate, the active isocyanate substituent at one end of the diphenylmethane-4,4'-diisocyanate structure can perform surface modification on the aluminosilicate fiber to obtain isocyanate-modified aluminosilicate fiber. Then, under high-temperature conditions, the isocyanate group can further react with the end-capped primary amine group in the structure of the polymeric macromolecular modifier, thereby modifying the polymeric macromolecular modifier on the surface of the aluminosilicate fiber to obtain the fiber material.

[0040] The preparation method of the polymeric macromolecular modifier is specifically as follows:

[0041] 1.2 g of 4,4'-diaminostilbene-2,2'-disulfonic acid and 0.8 g of 2,3-dibromosuccinic acid were added to 1,4-dioxane. Stirring was started until a homogeneous reaction solution was formed. Nitrogen was introduced to expel air. Then, a heating program was started, and the heating rate was controlled at 3 °C / min. The temperature was raised to 75 °C and kept stirring for 8 h. Then, the temperature was lowered to 55 °C, and 5 mL of a 25% sodium hydroxide aqueous solution was added to the reaction solution. After addition, stirring was continued while keeping the temperature for 6 h. The solvent was evaporated to remove, and the product was collected to obtain the polymeric macromolecular modifier.

[0042] The polymeric macromolecular modifier was subjected to infrared analysis and testing, and the results were as Figure 1 shown. The absorption peaks at 3308 cm -1 and 3364 cm -1 were the characteristic absorption peaks of N-H in primary amine and secondary amine groups. The absorption peaks at 3000 cm -1 to 3100 cm -1 were the characteristic absorption peaks of C-H on the benzene ring skeleton. The absorption peak at 1716 cm -1 was the characteristic absorption peak of C=O of the carboxyl group. The absorption peak at 1389 cm -1 was the characteristic absorption peak of S=O of the sulfonic acid group. And no C-Br characteristic absorption peak appeared at 500 cm -1 to 600 cm -1 . It can be speculated that the principle of the above scheme is that under the action of sodium hydroxide, the active substituted amino group in the structure of 4,4'-diaminostilbene-2,2'-disulfonic acid and the halogen substituent in the structure of 2,3-dibromosuccinic acid undergo continuous substitution reactions to form a macromolecular substance with a polymeric structure, that is, the polymeric macromolecular modifier. Since an excessive amount of 4,4'-diaminostilbene-2,2'-disulfonic acid was used, this polymeric macromolecular modifier showed amino capping. Example 1

[0043] A multi-component concrete based on Portland cement includes the following raw materials by weight parts:

[0044] Portland cement 45 parts;

[0045] Fly ash 5 parts;

[0046] Fiber material 4 parts;

[0047] Aggregate 50 parts;

[0048] Coarse aggregate 30 parts;

[0049] Water reducing agent 2 parts;

[0050] Water 40 parts;

[0051] The method for preparing the multi-component concrete comprises the following steps:

[0052] The first step is to prepare all the raw materials according to the weight proportions;

[0053] The second step is to place silicate cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir them evenly at a stirring rate of 500r / min, then adjust the stirring rate to 300r / min, continue to add water reducer and water and stir for 20 minutes.

[0054] Among them, the silicate cement is 42.5R type ordinary silicate cement; the fly ash is Class I fly ash; the fiber material is the fiber material prepared in the preparation example; the aggregate is fine stone with a particle size of 10 mm; the aggregate is river sand with a particle size of 5 mm; the water reducer is SPC-100 polycarboxylic acid water reducer, the same below. Example 2

[0055] A multi-component concrete based on silicate cement, comprising the following raw materials in parts by weight:

[0056] 46 parts of Portland cement;

[0057] 6 parts of fly ash;

[0058] 5 parts of fiber material;

[0059] Aggregate 55 parts;

[0060] Aggregate 32 parts;

[0061] 2.5 parts of water reducing agent;

[0062] 45 parts water;

[0063] The method for preparing the multi-component concrete comprises the following steps:

[0064] The first step is to prepare all the raw materials according to the weight proportions;

[0065] The second step is to place silicate cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir them evenly at a stirring rate of 600r / min, then adjust the stirring rate to 400r / min, continue to add water reducer and water and stir for 15 minutes. Example 3

[0066] A multi-component concrete based on silicate cement, comprising the following raw materials in parts by weight:

[0067] 48 parts of Portland cement;

[0068] 6 parts of fly ash;

[0069] 8 parts of fiber material;

[0070] 55 parts of aggregate;

[0071] 35 parts of aggregate;

[0072] 3 parts of water reducing agent;

[0073] 50 parts of water;

[0074] The preparation method of the multi-component concrete comprises the following steps:

[0075] First step, prepare all raw materials according to the weight parts;

[0076] Second step, at a stirring rate of 1000 r / min, place the portland cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir and mix evenly, then adjust the stirring rate to 500 r / min, continue to add the water reducing agent and water and stir. After 10 min, it is ready. Example 4

[0077] A multi-component concrete based on portland cement, comprising the following raw materials according to weight parts:

[0078] 50 parts of portland cement;

[0079] 8 parts of fly ash;

[0080] 10 parts of fiber material;

[0081] 60 parts of aggregate;

[0082] 36 parts of aggregate;

[0083] 4 parts of water reducing agent;

[0084] 60 parts of water;

[0085] The preparation method of the multi-component concrete comprises the following steps:

[0086] First step, prepare all raw materials according to the weight parts;

[0087] Second step, at a stirring rate of 1000 r / min, place the portland cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir and mix evenly, then adjust the stirring rate to 500 r / min, continue to add the water reducing agent and water and stir. After 10 min, it is ready.

[0088] Comparative Example 1

[0089] A multi-component concrete based on portland cement, comprising the following raw materials according to weight parts:

[0090] Portland cement: 46 parts;

[0091] Fly ash: 6 parts;

[0092] Aluminum silicate fiber: 5 parts;

[0093] Aggregate: 55 parts;

[0094] Coarse aggregate: 32 parts;

[0095] Water reducing agent: 2.5 parts;

[0096] Water: 45 parts;

[0097] The preparation method of the multi-component concrete comprises the following steps:

[0098] First step, prepare each raw material according to the weight parts;

[0099] Second step, at a stirring rate of 600 r / min, place Portland cement, fly ash, aluminum silicate fiber, aggregate and coarse aggregate in a mixer and stir evenly, then adjust the stirring rate to 400 r / min, continue to add water reducing agent and water and stir. After 15 min, it is ready.

[0100] Comparative Example 2

[0101] A multi-component concrete based on Portland cement, comprising the following raw materials in parts by weight:

[0102] Portland cement: 46 parts;

[0103] Fly ash: 6 parts;

[0104] Aggregate: 55 parts;

[0105] Coarse aggregate: 32 parts;

[0106] Water reducing agent: 2.5 parts;

[0107] Water: 45 parts;

[0108] The preparation method of the multi-component concrete comprises the following steps:

[0109] First step, prepare each raw material according to the weight parts;

[0110] Second step, at a stirring rate of 600 r / min, place Portland cement, fly ash, aggregate and coarse aggregate in a mixer and stir evenly, then adjust the stirring rate to 400 r / min, continue to add water reducing agent and water and stir. After 15 min, it is ready.

[0111] Test Example

[0112] Perform performance tests on the concrete in the examples and comparative examples, and the results are recorded in Table 1:

[0113]

[0114] Note: For the test of mechanical strength, the reference standard is GB / T 50081-2019, and the test time is 28 days after the conventional curing of concrete; for the test of cracking performance, the reference standard is JGJ / T 70-2009;

[0115] In the present invention, aluminosilicate fibers are modified by using a polymeric macromolecular modifier, so that a large number of molecular chains of the polymeric macromolecular modifier are coated on the surface of the aluminosilicate fibers, and the obtained fiber material as a whole presents a micro dendritic three-dimensional structure. When mixed with base materials such as cement, these dendritic micro three-dimensional structures will extend to various regions of the cement matrix to form a "mortise and tenon" structure, and then firmly embed in the concrete structure, thereby generating good bonding performance between each other. Since the molecular chain structure of the polymeric macromolecular modifier contains a large number of sulfonic acid and carboxylic acid active substituents, these active substituents can act with calcium hydroxide in the initial stage of cement hydration, and greatly increase the hydration rate of tricalcium silicate, thereby inhibiting the phenomenon of forming a loose structure in the initial stage of tricalcium silicate hydration, making the connection between cement and aluminosilicate fibers closer, reducing the porosity of concrete, and thus combining with the strengthening effect of aluminosilicate fibers themselves, so that the prepared concrete exhibits excellent mechanical strength and crack resistance, etc.

[0116] Analysis of the test results shows that using the fiber material prepared in the preparation example as a concrete additive can make the prepared concrete exhibit excellent mechanical strength and anti-cracking performance. Using unmodified aluminosilicate fibers to replace the fiber material as an additive, the mechanical strength and anti-cracking performance of the concrete both decrease significantly. This is because the gap between the aluminosilicate fibers and the cement as well as the aggregate is large, and the bonding force is not strong, resulting in the aluminosilicate fibers being unable to play their role efficiently. After directly removing the aluminosilicate fibers, the various properties of the concrete further decrease, indicating that the addition of aluminosilicate fibers has an obvious positive effect on improving the comprehensive performance of the concrete.

[0117] In this article, specific examples are used to elaborate on the principles and implementation modes of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention, including the best mode, and also enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements approximately the same as the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

[0118] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing multi-component concrete based on Portland cement, characterized in that: The multi-component concrete comprises the following raw materials in parts by weight: 45-50 parts of Portland cement; 5-8 parts of fly ash; 4-10 parts of fiber material; Aggregate 50-60 parts; Aggregate 30-36 parts; 2-4 parts of water reducing agent; 40-60 parts of water; The preparation method comprises the following steps: The first step is to prepare all the raw materials according to the weight proportions; Step 2: Place the silicate cement, fly ash, fiber material, aggregate and aggregate in a mixer and stir at a stirring rate of 500-1000r / min, then adjust the stirring rate to 300-500r / min, continue to add water reducer and water and stir for 10-20 minutes; The preparation method of the fiber material specifically comprises the following steps: Step 1: Under the action of a tin catalyst, the aluminum silicate fiber is surface-modified using a diisocyanate monomer to obtain a modified aluminum silicate fiber; Step 2: Using N,N-dimethylformamide as a medium, further modifying the modified aluminum silicate fiber with a polymeric macromolecular modifier to obtain a fiber material; The preparation method of the polymeric macromolecular modifier is specifically as follows: Add 4,4'-diaminostilbene-2,2'-disulfonic acid and 2,3-dibromosuccinic acid to 1,4-dioxane, start stirring until a uniform reaction liquid is formed, introduce nitrogen, exhaust the air, then start the heating program, control the heating rate to 3-5°C / min, raise the temperature to 70-80°C, keep stirring for 6-9h, then lower the temperature to 50-60°C, add an acid binding agent to the reaction liquid, continue to keep stirring for 4-8h after the addition is complete, evaporate and remove the solvent, collect the product, and the polymerized macromolecular modifier can be obtained.

2. The method for preparing a multi-component concrete based on Portland cement according to claim 1, characterized in that: The silicate cement is 42.5R type ordinary silicate cement or 52.5R type ordinary silicate cement; the fly ash is Class I fly ash or Class II fly ash; the aggregate is fine stone with a particle size of ≤10mm; the aggregate is river sand with a particle size of ≤5mm; the water reducer is a naphthalene-based water reducer or a polycarboxylic acid water reducer.

3. The method for preparing a multi-component concrete based on Portland cement according to claim 1, characterized in that: In step 1, the tin catalyst is any one of dibutyltin diacetate, stannous octoate or dibutyltin dilaurate.

4. The method for preparing a multi-component concrete based on Portland cement according to claim 1, characterized in that: In step 1, the diisocyanate monomer is any one of isophorone diisocyanate, toluene diisocyanate or diphenylmethane-4,4'-diisocyanate.

5. The method for preparing a multi-component concrete based on Portland cement according to claim 1, characterized in that: The molar ratio of the 4,4'-diaminostilbene-2,2'-disulfonic acid to the 2,3-dibromosuccinic acid is 1-1.2:

1.

6. The method for preparing a multi-component concrete based on Portland cement according to claim 1, characterized in that: The acid binding agent is an alkaline hydroxide aqueous solution with a mass fraction of 20-30%.

7. The method for preparing a multi-component concrete based on Portland cement according to claim 6, characterized in that: The alkaline hydroxide is potassium hydroxide or sodium hydroxide.

8. A multi-component concrete based on Portland cement, characterized in that: The method is prepared according to any one of claims 1 to 7.

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