Concrete admixture with impervious and anti-cracking functions and preparation method thereof

Abstract

The invention discloses a concrete admixture with impervious and anti-cracking functions and a preparation method thereof, and belongs to the technical field of concrete admixtures. According to the technical scheme, the cleaning agent comprises the following raw materials in parts by weight: 30-80 parts of a complexing agent, 3-30 parts of a surfactant, 7-50 parts of a dispersing agent and 5-15 parts of a stabilizer. The admixture prepared by the invention synergistically couples free calcium ions, magnesium ions, metal ions and silicate in concrete to form a composite cross-linked network structure to prevent permeation of water molecules; reduction of the content of metal ions and the like can significantly reduce the shrinkage cracking effect of the concrete and improve the chemical durability and stability of the concrete.

Description

Technical Field

[0001] The invention relates to a concrete admixture with both anti-seepage and anti-cracking functions and a preparation method thereof, and specifically belongs to the technical field of concrete admixtures. Background Art

[0002] In the field of construction engineering, concrete is the core of structural materials, and its performance is directly related to the safety, durability and economy of the entire project. However, as modern buildings develop towards higher, larger and more complex directions, the environmental challenges faced by concrete are becoming increasingly severe. Especially in extreme environments such as heavy rain, frequent earthquakes, and high salt fog, the cracks and leakage problems of concrete structures are particularly prominent. Cracks not only weaken the overall stability of the structure, but also easily become penetration channels for harmful substances such as moisture and salt, accelerating the deterioration process of concrete. Leakage directly threatens the use function and living safety of the building, and in severe cases even leads to structural failure.

[0003] To solve the above problems, domestic and foreign scholars and engineers have developed a variety of concrete admixtures to improve the crack resistance and impermeability of concrete. A concrete anti-cracking waterproofing agent based on polymer materials effectively prevents the intrusion of moisture and other harmful substances by forming a dense waterproof layer, while enhancing the crack resistance of concrete. However, in practical applications, this admixture has problems such as poor compatibility with the concrete substrate and affecting the working performance of concrete. In addition, a concrete anti-cracking and anti-permeability enhancer based on inorganic nanomaterials significantly improves the density and impermeability of concrete through the filling effect and interface effect of nanomaterials. However, this method has limitations such as high cost and complex preparation process, and the improvement of the mechanical properties of concrete is limited.

[0004] It is worth noting that most of the existing concrete anti-cracking and anti-seepage admixtures focus on improving a single performance, while ignoring the fact that concrete is a complex multiphase system, and its performance improvement requires comprehensive consideration of multiple factors. In addition, with the enhancement of environmental awareness, the environmental friendliness and sustainability of admixtures have also become issues that cannot be ignored. Therefore, it is particularly important to develop a new type of concrete admixture that has excellent anti-cracking and anti-seepage properties, maintains good working performance and mechanical properties of concrete, and meets environmental protection requirements. The admixture should be able to significantly improve the durability and service life of concrete, reduce the maintenance costs caused by cracks and leakage, and provide a more reliable, economical and environmentally friendly solution for modern construction projects. Summary of the invention

[0005] The present invention provides a concrete admixture with both anti-seepage and anti-cracking functions and a preparation method thereof. Through the synergistic coupling effect of various added chemical components, the durability and service life of concrete are significantly improved, the good working performance and mechanical properties of concrete are maintained, the maintenance cost caused by cracks and leakage is reduced, and a more reliable, economical and environmentally friendly solution is provided for modern construction projects.

[0006] The present invention provides a concrete admixture with both anti-seepage and anti-cracking functions, which is achieved through the following implementation scheme:

[0007] The invention comprises the following raw materials in parts by weight: 30-80 parts by weight of substance A, 3-30 parts by weight of surfactant, 7-50 parts by weight of dispersant and 5-15 parts by weight of stabilizer; the substance A is one or more of methyl ethyl ketone oxime, dimethyl ketone oxime and acetaldehyde oxime.

[0008] As a configuration scheme of the present invention, the surfactant is one or more of sodium secondary alkyl sulfonate, sodium alkylbenzene sulfonate, and triethanolamine alkylbenzene sulfonate.

[0009] As a setting scheme of the present invention, the dispersant is one or more of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, and trisodium phosphate.

[0010] As a configuration scheme of the present invention, the stabilizer is one or more of methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

[0011] The present invention also claims a method for preparing a concrete admixture having both anti-seepage and anti-cracking functions, comprising the following steps:

[0012] (1) placing complex substance A and surfactant into a container and stirring them evenly to obtain a mixture A;

[0013] (2) adding a dispersant and a stabilizer to the mixture A, stirring, and heating at a constant temperature to keep the mixture warm; continuing to stir, and after the stirring is completed, allowing the mixture to stand at room temperature to obtain a concrete admixture having both anti-seepage and anti-cracking functions.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The present invention uses substance A to synergistically couple the free calcium ions, magnesium ions, metal ions and silicates in the concrete, thereby reducing the time-dependent loss of the slump of the concrete, having a certain auxiliary water-reducing effect, and is suitable for various types of reducing mother liquid to increase the compressive strength of the concrete, reduce the water seepage height, and significantly reduce the degree of cracking of the concrete.

[0016] (2) The present invention adds the concrete admixture having both anti-seepage and anti-cracking functions to concrete, utilizes the substance A, surfactant, dispersant and stabilizer in the admixture to react synergistically with the concrete, and reduces the metal ion content, which can significantly reduce the shrinkage cracking effect of the concrete, improve the chemical durability and stability of the concrete, effectively prevent the penetration of moisture, salt and other harmful substances, and extend the service life of the concrete structure.

[0017] (3) The concrete admixture with both anti-seepage and anti-cracking functions of the present invention can improve the microstructure of concrete and effectively resist the formation of cracks caused by factors such as temperature changes and loads. It is suitable for projects with complex structures such as large spans, high-rise buildings and bridges, and reduces the decline in structural strength and durability caused by cracks.

[0018] (4) The present invention uses environmentally friendly raw materials, which are widely available, cheap and easy to obtain, and reduce the emission of harmful substances during the production process. It is suitable for construction projects such as basements, reservoirs, tunnels, etc. that require high anti-seepage performance, reducing maintenance costs and safety hazards caused by leakage, and meeting the requirements of green buildings and sustainable development. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0020] Example 1

[0021] A method for preparing a concrete admixture having both anti-seepage and anti-cracking functions comprises the following steps:

[0022] (1) Weigh 50 parts of methyl ethyl ketone oxime and 10 parts of sodium secondary alkyl sulfonate into a container, and stir them at a speed of 3000 r / min for 30 minutes using a stirrer to obtain a mixture A.

[0023] (2) Weigh 20 parts of sodium hexametaphosphate and 8 parts of methyl cellulose and add them to mixture A. Use a mixer to stir the mixture at a speed of 1000 r / min for 120 minutes, then place it in a 50°C constant temperature drying oven for insulation for 18 hours. After the insulation is completed, the mixture is further stirred at a speed of 500 r / min for 40 minutes using a mixer and then allowed to stand at room temperature for 4 hours to obtain a concrete admixture with both anti-seepage and anti-cracking functions.

[0024] Example 2

[0025] A concrete admixture with both anti-seepage and anti-cracking functions, the preparation method of which comprises the following steps:

[0026] (1) Weigh 70 parts of dimethyl ketoxime and 23 parts of sodium alkylbenzene sulfonate into a container, and stir them at a speed of 3500 r / min for 50 min using a stirrer to obtain a mixture A.

[0027] (2) 37 parts of sodium tripolyphosphate and 12 parts of hydroxyethyl cellulose were weighed and added to mixture A, and stirred at a speed of 1200 r / min for 160 min using a mixer, and then placed in a 55° C. constant temperature drying oven for insulation for 20 h. After the insulation, the mixture was further stirred at a speed of 800 r / min for 50 min using a mixer and then allowed to stand at room temperature for 5 h, thereby obtaining a concrete admixture with both anti-seepage and anti-cracking functions.

[0028] Example 3

[0029] A concrete admixture with both anti-seepage and anti-cracking functions, the preparation method of which comprises the following steps:

[0030] (1) Weigh 40 parts of acetaldehyde oxime and 8 parts of alkylbenzenesulfonic acid triethanolamine into a container, and stir the mixture at a speed of 2200 r / min for 30 minutes to obtain a mixture A.

[0031] (2) Weigh 15 parts of sodium pyrophosphate and 7 parts of hydroxypropyl methylcellulose and add them to mixture A. Use a mixer to stir the mixture at a speed of 900 r / min for 80 minutes, then place it in a 45°C constant temperature drying oven for insulation for 14 hours. After the insulation is completed, the mixture is further stirred at a speed of 400 r / min for 40 minutes using a mixer and then allowed to stand at room temperature for 3 hours to obtain a concrete admixture with both anti-seepage and anti-cracking functions.

[0032] Example 4

[0033] A concrete admixture with both anti-seepage and anti-cracking functions, the preparation method of which comprises the following steps:

[0034] (1) Weigh 60 parts of methyl ethyl ketone oxime and 18 parts of alkylbenzenesulfonic acid triethanolamine into a container, and stir the mixture at a speed of 3000 r / min for 40 minutes to obtain a mixture A.

[0035] (2) Weigh 32 parts of trisodium phosphate and 10 parts of hydroxyethyl cellulose and add them to mixture A. Use a mixer to stir the mixture at a speed of 1200 r / min for 100 min, then place it in a 50°C constant temperature drying oven for insulation for 16 h. After the insulation, continue to use a mixer to stir the mixture at a speed of 600 r / min for 45 min and then let it stand at room temperature for 3 h to obtain a concrete admixture with both anti-seepage and anti-cracking functions.

[0036] Example 5

[0037] A concrete admixture with both anti-seepage and anti-cracking functions, the preparation method of which comprises the following steps:

[0038] (1) Weigh 55 parts of dimethyl ketoxime and 17 parts of sodium secondary alkyl sulfonate into a container, and stir them at a speed of 3000 r / min for 40 minutes using a stirrer to obtain a mixture A.

[0039] (2) Weigh 29 parts of sodium tripolyphosphate and 10 parts of hydroxypropyl methylcellulose and add them to mixture A. Use a mixer to stir the mixture at a speed of 1100 r / min for 110 minutes, then place it in a 50°C constant temperature drying oven for insulation for 16 hours. After the insulation is completed, the mixture is further stirred at a speed of 600 r / min for 45 minutes using a mixer and then allowed to stand at room temperature for 3 hours to obtain a concrete admixture with both anti-seepage and anti-cracking functions.

[0040] Comparative Example 1

[0041] The comparative example of the present invention is substantially the same as Example 1, except that there is no methyl ethyl ketone oxime in this comparative example.

[0042] Comparative Example 2

[0043] The comparative example of the present invention is substantially the same as Example 1, except that there is no sodium secondary alkyl sulfonate in this comparative example.

[0044] Comparative Example 3

[0045] The comparative example of the present invention is substantially the same as Example 1, except that sodium hexametaphosphate is absent in the comparative example.

[0046] Comparative Example 4

[0047] The comparative example of the present invention is substantially the same as Example 1, except that there is no methyl cellulose in this comparative example.

[0048] Comparative Example 5

[0049] The difference between the comparative example of the present invention and Example 1 is that methyl ethyl ketone oxime is replaced by diethylenetriaminepentaacetic acid.

[0050] Experimental example

[0051] Preparation of concrete specimens:

[0052] According to the current standards and specifications, with C35 concrete as the benchmark, the admixtures in Examples 1-5 and Comparative Examples 1-5 were added to prepare standard concrete test blocks, and standard concrete test blocks without any admixtures were set. The concrete was cured for 28 days under standard conditions, and then the concrete performance test was carried out in accordance with GB / T50081-2019 Test Method for Physical and Mechanical Properties of Concrete and GB / T50082-2009 Standard for Test Method for Long-term Performance and Durability of Ordinary Concrete. The test results are shown in Table 1.

[0053] Table 1 Concrete performance indicators

[0054]

[0055] As can be seen from Table 1, the concrete admixtures prepared by the present invention in Examples 1-5 have a 24-hour water seepage height index that is much smaller than that of the concrete admixtures prepared in Comparative Examples 1-5 and the blank control group with incomplete components, which proves that the prepared concrete admixtures have good anti-seepage performance; the average cracking area per unit area is reduced by 20-30 times as a whole, which shows that the anti-seepage and anti-cracking admixture of the present invention can significantly reduce the shrinkage cracking effect of concrete, improve the chemical durability and stability of concrete, and can effectively improve the chemical durability and stability of concrete, prevent the penetration of moisture, salt and other harmful substances, and extend the service life of concrete structures; the compressive strength is also significantly higher than the design value, indicating that the prepared concrete admixture is compatible with the concrete substrate and has better compressive durability.

[0056] According to Example 1 and Comparative Examples 1-4, in the concrete admixture system having both anti-seepage and anti-cracking functions of the present invention, when one of substance A, surfactant, dispersant and stabilizer is missing, the average cracking area is significantly reduced by 15-30 times, and the compressive strength and anti-seepage effect are also significantly improved, indicating that substance A, surfactant, dispersant and stabilizer work synergistically to enhance the anti-seepage, anti-cracking and compressive effects of the concrete admixture.

[0057] According to the comparison of the test results of comparative examples 1-5 with the blank control group, it can be seen that without any of the chemical admixtures, the compressive strength, water seepage effect and average cracking area are not significantly improved; only when the four substances exist at the same time, the compressive strength, water seepage effect and average cracking area are significantly improved, and the most obvious is that the average cracking area is reduced by 15-30 times; when substance A is replaced with diethylenetriaminepentaacetic acid, its compressive strength effect is significantly weakened, the water seepage height shows an increasing trend, and the increased average cracking area is as high as 17 times, which further proves that substance A, surfactant, dispersant and stabilizer work synergistically to enhance the anti-seepage, anti-cracking and compressive effects of concrete admixtures.

[0058] The above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. Therefore, the obvious changes or modifications derived are still within the protection scope of the invention.

Claims

1. A concrete admixture having both anti-seepage and anti-cracking functions, characterized in that: The invention comprises the following raw materials in parts by weight: 30-80 parts by weight of substance A, 3-30 parts by weight of surfactant, 7-50 parts by weight of dispersant and 5-15 parts by weight of stabilizer; the substance A is one or more of methyl ethyl ketone oxime, dimethyl ketone oxime and acetaldehyde oxime.

2. The concrete admixture having both anti-seepage and anti-cracking functions according to claim 1, characterized in that: The surfactant is one or more of sodium secondary alkyl sulfonate, sodium alkylbenzene sulfonate, and triethanolamine alkylbenzene sulfonate.

3. The concrete admixture having both anti-seepage and anti-cracking functions according to claim 1, characterized in that: The dispersant is one or more of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate and trisodium phosphate.

4. The concrete admixture having both anti-seepage and anti-cracking functions according to claim 1, characterized in that: The stabilizer is one or more of methyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose.

5. A method for preparing a concrete admixture having both anti-seepage and anti-cracking functions as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) placing substance A and a surfactant into a container and stirring to obtain a mixture A; (2) Add the dispersant and the stabilizer to the mixture A, stir evenly, heat and keep the mixture at a constant temperature, continue stirring, and after stirring, let it stand at room temperature to obtain a concrete admixture with both anti-seepage and anti-cracking functions.

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