Special high-strength concrete liquid admixture for mine shaft and preparation method of special high-strength concrete liquid admixture

Abstract

The invention belongs to the technical field of concrete admixtures, and particularly relates to a special high-strength concrete liquid admixture for a mine shaft and a preparation method of the special high-strength concrete liquid admixture. The concrete has high fluidity, good slump retaining property, early strength, high strength, freezing resistance, crack resistance, water resistance and excellent durability under the condition of low mixing amount. The liquid admixture adopts an automatic metering and feeding mode, can realize accurate control and automatic data acquisition, avoids dust pollution and metering error of the powder admixture, and is suitable for digital mixing stations and green and environment-friendly construction requirements.

Description

Technical Field

[0001] This invention belongs to the field of concrete admixture technology, specifically relating to a high-strength liquid admixture for mine shafts and its preparation method. Background Technology

[0002] Currently, mine shaft construction still mainly uses the freezing method. This method requires the formation of shaft wall concrete under extremely low temperature conditions, which places higher demands on concrete materials: they must have good antifreeze properties, rapid early strength growth, excellent crack resistance, high impermeability, and long-term stable durability in negative temperature environments.

[0003] Currently, most high-strength concrete admixtures for shafts utilize powder admixture systems. In actual engineering projects, powder admixtures are typically added manually. However, with the upgrading of batching plant equipment and the improvement of digital management in concrete production, various data from the concrete production process need to be automatically collected and permanently stored for quality traceability and monitoring. Powder admixtures suffer from drawbacks such as inaccurate weighing, poor timeliness of addition, severe dust pollution, and the inability to be automatically recorded by production equipment, making it difficult to meet the requirements of modern digital production and green construction of shaft concrete. Summary of the Invention

[0004] To address the problems in the background technology, this invention provides a high-strength concrete liquid admixture for mine shafts and its preparation method.

[0005] The technical solution of the present invention is as follows: This invention provides a high-strength concrete liquid admixture for mine shafts, which is composed of the following components in parts by weight: 20-70 parts by weight of water-reducing agent, 1-4 parts by weight of water-based nano crack-resistant and seepage-proof agent, 1-6 parts by weight of triisopropanolamine, 3-7 parts by weight of anhydrous sodium sulfate, 0.05-0.2 parts by weight of defoamer, and 30-70 parts by weight of water.

[0006] Based on the above-mentioned high-strength concrete liquid admixture for mine shafts, it is composed of the following components in parts by weight: 26 parts by weight of water-reducing agent, 4 parts by weight of triisopropanolamine, 4 parts by weight of water-based nano crack-resistant and seepage-proof agent, 3 parts by weight of anhydrous sodium sulfate, 0.1 parts by weight of defoamer, and 63 parts by weight of water.

[0007] Based on the above-mentioned high-strength concrete liquid admixture for mine shafts, the water-reducing agent is a polycarboxylate water-reducing agent; and the defoamer is a polyether defoamer.

[0008] Based on the above-mentioned high-strength concrete liquid admixture for mine shafts, the purity of the triisopropanolamine is 99%, and the purity of the anhydrous sodium sulfate is 99%.

[0009] The present invention also provides a method for preparing the aforementioned high-strength concrete liquid admixture for mine shafts, comprising the following steps: (1) Add water to the reaction apparatus and turn on the stirrer; (2) Add water-reducing agent, water-based nano anti-crack and seepage-proof agent, triisopropanolamine and defoamer to the reaction device in sequence; (3) Add anhydrous sodium sulfate into the reaction apparatus and continue stirring.

[0010] The temperature of the reaction apparatus is controlled between 20 and 50°C.

[0011] The present invention also provides the application of the high-strength concrete liquid admixture for mine shafts in the preparation of concrete for mine shafts. The liquid admixture is mixed with mixing water and then added to the concrete mixture to prepare concrete with strength grades of C50 to C100.

[0012] Furthermore, the amount of the liquid admixture added during concrete preparation is 3-8% of the total weight of the concrete mixture.

[0013] The specific steps are as follows: Sand and gravel are added to the mixer and mixed evenly. Then cement, fly ash, mineral powder, and silica fume are added continuously and mixed again to obtain a concrete mixture. At the same time, according to the target strength grade of the concrete, liquid admixtures are mixed evenly with the mixing water, and the mixture is added to the mixer and mixed for a preset time.

[0014] It also includes: collecting quality test data of liquid admixtures, determining the range of concrete strength grades corresponding to the batch of liquid admixtures based on the test data, and determining the target liquid admixture and dosage based on the target concrete strength grade.

[0015] Beneficial effects The liquid admixture provided by this invention, by constructing a composite system of "high-efficiency water reduction - nano-seepage prevention - early strength and setting promotion", enables concrete to simultaneously possess high fluidity, good slump retention, early strength, high strength, freeze resistance, crack resistance, waterproofing and excellent durability under low admixture conditions.

[0016] The liquid admixture of this invention adopts an automatic metering and dosing method, which can achieve precise control and automatic data collection, avoid dust pollution and metering errors of powder admixtures, and is suitable for digital mixing plants and green and environmentally friendly construction needs. Detailed Implementation

[0017] The following examples are intended to illustrate the present invention, and not to further limit the invention.

[0018] The construction environment for mine shaft concrete is extreme, with deep shafts, significant temperature gradients, and frequent sub-zero temperatures or freezing conditions. Especially in freezing method construction, the concrete must rapidly develop early strength at low temperatures to resist frost heave damage. Furthermore, the frequent frost heave and thawing cycles place far higher demands on the frost resistance of the concrete compared to ordinary structural concrete.

[0019] Well shafts typically traverse aquifers, gravel layers, or water-rich fissure zones, where groundwater pressure is high. Therefore, the concrete must possess high impermeability and compressive compactness, making waterproofing and seepage prevention the core requirements for well shaft concrete.

[0020] In addition, as the lifeline of the mine, the shaft has a long service life and needs to withstand the pressure of the surrounding rock and dynamic loads for a long time, which places extremely high demands on the concrete's resistance to carbonation, corrosion, durability and toughness.

[0021] The narrow construction space and long pumping distance mean that concrete must not only have high fluidity and good slump retention, but also that admixtures must maintain stable dispersibility and anti-segregation ability during long-distance pumping.

[0022] In summary, admixtures for mine shaft concrete must simultaneously meet a series of special properties such as low-temperature early strength, high strength, high impermeability, frost resistance, crack resistance, good slump retention, and high durability, which are fundamentally different from ordinary engineering admixtures.

[0023] In response, this invention provides a high-strength concrete liquid admixture for mine shafts, which is composed of the following components in parts by weight: 20-70 parts by weight of water-reducing agent, 1-4 parts by weight of water-based nano crack-resistant and seepage-proof agent, 1-6 parts by weight of triisopropanolamine, 3-7 parts by weight of anhydrous sodium sulfate, 0.05-0.2 parts by weight of defoamer, and 30-70 parts by weight of water.

[0024] Preferably, it is composed of the following components in parts by weight: 26 parts by weight of water-reducing agent, 4 parts by weight of triisopropanolamine, 4 parts by weight of water-based nano crack-resistant and seepage-proof agent, 3 parts by weight of anhydrous sodium sulfate, 0.1 parts by weight of defoamer, and 63 parts by weight of water.

[0025] The water-reducing agent is a polycarboxylate water-reducing agent; the defoamer is a polyether defoamer.

[0026] The triisopropanolamine has a purity of 99%, and the anhydrous sodium sulfate has a purity of 99%. The preferred water-based nano-crack-resistant and seepage-proof agent is a product of Kolo.

[0027] This invention selects a polycarboxylate-based high-efficiency water-reducing system, which combines high water reduction rate with excellent slump retention, and can adapt to the narrow space and pumping requirements of wells; a water-based nano-crack-resistant and seepage-proof system improves the seepage resistance and crack resistance to cope with the high water pressure environment of wells; anhydrous sodium sulfate and triisopropanolamine meet the low-temperature early strength requirements of well freezing methods. The synergistic effect of the components significantly improves the adaptability of well concrete under low temperature, freezing, high water pressure and narrow space construction conditions.

[0028] The present invention also provides a method for preparing the aforementioned high-strength concrete liquid admixture for mine shafts, comprising the following steps: (1) Add water to the reaction apparatus and turn on the stirrer; (2) Add water-reducing agent, water-based nano anti-crack and seepage-proof agent, triisopropanolamine and defoamer to the reaction device in sequence; (3) Add anhydrous sodium sulfate to the reaction apparatus and continue stirring. The temperature of the reaction apparatus should be controlled at 20-50℃.

[0029] The preparation process of this invention is simple and controllable. The liquid admixture form facilitates accurate measurement, automatic addition, and dust reduction, thus realizing green construction and digital management.

[0030] Furthermore, the preparation method includes the following steps: (1) Add a first preset weight part of water and a second preset weight part of water-reducing agent to a premixing device, stir, add water-based nano anti-crack and anti-seepage agent, and obtain a pre-dispersion liquid; (2) Add the remaining weight of water to the reaction apparatus and start stirring; (3) Add the remaining weight parts of water-reducing agent, pre-dispersion liquid, triisopropanolamine and defoamer to the reaction apparatus in sequence; (4) Add anhydrous sodium sulfate to the reaction apparatus and continue stirring. The temperature of the reaction apparatus should be controlled at 20-50℃.

[0031] Preferably, the weight ratio of the second preset weight part of water-reducing agent to the water-based nano crack-resistant and seepage-proof agent is 5 to 8:1, and the weight ratio of the second preset weight part of water-reducing agent to the first preset weight part of water is 1:1 to 2, ensuring that the pre-dispersed liquid has suitable viscosity and high dispersion stability.

[0032] Compared to the direct addition method without pre-dispersion treatment, this invention pre-mixes the water-based nano-crack-resistant and seepage-proof agent with the water-reducing agent mother liquor, forming a stable nano-suspension through steric hindrance, which can maintain its activity in complex systems. Furthermore, the resulting liquid admixture, when measured with a Zeta potential meter, has a Zeta potential value that is 5-10 mV higher than that obtained by the direct addition method.

[0033] The present invention also provides the application of the aforementioned high-strength concrete liquid admixture for mine shafts in the preparation of concrete for mine shafts. The liquid admixture is mixed with mixing water and then added to the concrete mixture to prepare concrete with strength grades of C50 to C100.

[0034] Preferably, the amount of liquid admixture added during concrete preparation is 3-8% of the total weight of the concrete mixture.

[0035] This invention constructs a composite system of "high-efficiency water reduction - nano-seepage prevention - early strength and setting promotion", enabling concrete to simultaneously possess high fluidity, good slump retention, early strength, high strength, frost resistance, crack resistance, waterproofing and excellent durability under low admixture conditions.

[0036] The specific steps are as follows: Sand and gravel are added to a mixer and mixed evenly. Then cement, fly ash, mineral powder, and silica fume are added continuously and mixed for another time to obtain a concrete mixture. At the same time, according to the target strength grade of the concrete, liquid admixtures are pre-mixed evenly with mixing water. The mixture is then added to the mixer and mixed for a preset time.

[0037] Furthermore, this invention establishes a digital management and control platform to collect all data during the preparation and application stages of liquid admixtures and saves it to a database for production guidance. This includes: Collect quality test data of liquid admixtures, determine the range of concrete strength grades corresponding to this batch of liquid admixtures based on the test data, and determine the target liquid admixture and dosage based on the target concrete strength grade.

[0038] Specifically, the performance indicators of each batch of liquid admixture are tested, including: water reduction rate, solid content, and early strength performance (mortar 1-day strength). Based on the test data, the type of liquid admixture for that batch is determined to be ultra-high strength, high strength, or medium-high strength, and mapped to a liquid admixture type-concrete grade mapping table to obtain the corresponding concrete strength grade range for that batch of liquid admixture. After the determination is completed, a unique label is generated.

[0039] The mapping table between liquid admixture types and concrete grades was obtained through systematic orthogonal experimental design and subsequent feedback optimization in actual production. Firstly, concrete performance tests were conducted in the laboratory using variables such as water reduction rate and solid content to initially establish the mapping relationship. Based on this, scaled-up experiments were carried out and applied in actual engineering projects, and the mapping relationship was optimized based on feedback from engineering practice.

[0040] When a batching plant receives a concrete production task, it checks the label based on the target strength grade of the concrete, determines the target liquid admixture, and automatically adds it according to the preset dosage.

[0041] Through the aforementioned digital management of production, the performance value of liquid admixtures is maximized, while ensuring the precision, efficiency, and environmental friendliness of concrete production.

[0042] The liquid admixture of this invention employs an automatic metering and dosing method, enabling precise control and automatic data acquisition. This avoids dust pollution and metering errors associated with powder admixtures, making it suitable for digital mixing plants and green construction requirements. Test results show that the liquid admixture of this invention can not only prepare high-performance concrete for mine shafts with strength grades of C50 to C100, but also achieves over 70% of the design strength after 7 days. Its impermeability, freeze-thaw resistance, and carbonation resistance are significantly superior to traditional powder admixtures. The liquid admixture of this invention is particularly suitable for mine shaft freezing construction and other underground engineering projects with high requirements for early strength, high strength, and durability.

[0043] Example 1 This embodiment provides a high-strength concrete liquid admixture for mine shafts and its preparation method, as follows: 29 kg of polycarboxylate superplasticizer, 4 kg of triisopropanolamine, 4 kg of Kolo Building Materials water-based nano crack-resistant and seepage-proof agent, 3 kg of anhydrous sodium sulfate, 0.1 kg of defoamer, and 60 kg of water.

[0044] Add 40 kg of water to the reactor, start stirring, and then add water-reducing agent, water-based nano crack-resistant and seepage-proof agent, triisopropanolamine and defoamer in sequence. After rinsing the container containing each raw material with the remaining 20 kg of water, add it to the reactor, and then add anhydrous sodium sulfate to the reactor. Continue stirring for 30 minutes to obtain the product.

[0045] Example 2 This embodiment provides a high-strength concrete liquid admixture for mine shafts and its preparation method, as follows: (1) Add 30 kg of water and 20 kg of polycarboxylate superplasticizer to the premixing device, stir, add 4 kg of water-based nano anti-crack and anti-seepage agent to obtain a pre-dispersion liquid; (2) Add 30 kg of water to the reactor and start stirring; (3) Add 9 kg of water-reducing agent, pre-dispersion liquid, 4 kg of triisopropanolamine and 0.1 kg of defoamer to the reaction vessel in sequence; (4) Add 3 kg of anhydrous sodium sulfate to the reactor and continue stirring. The temperature of the reactor should be controlled at 20-50℃.

[0046] Application Example 1 Based on Example 2, this application example provides an application of the aforementioned high-strength concrete liquid admixture for mine shafts in the preparation of concrete for mine shafts. The application location is the post-cast strip of the main building of a commercial building in City A. The prepared C60 ready-mixed concrete is constructed in winter, with an atmospheric temperature of -10℃ and a concrete structure formwork temperature of -10℃. The construction and curing conditions are similar to those of a single-layer frozen well wall structure. The production process is dust-free and pollution-free, with accurate measurement. The production data has been automatically collected and stored by the production equipment. The produced concrete can meet the requirements of early strength, frost resistance, impermeability, shrinkage reduction and crack resistance, carbonation resistance, and high strength.

[0047] Raw materials and related parameters used in concrete preparation.

[0048] Cement: Conch P·O42.5; Shanshui P·O52.5; Sand: Jining Conch, fineness modulus 3.3, coarse sand, crushing value 17, methylene blue 1.4, stone powder content 8%; Aggregate: Jining Conch, size 5mm-20mm, crushing value 9, mud content 0.3%, needle-like and flaky content 5%; continuous gradation; Fly ash: Laiwu Guodian, Grade 1; Mineral powder: Shiheng Special Steel, S95 grade; Water is tap water.

[0049] The production process involves first putting sand and gravel into a mixer and forcibly mixing them evenly, then continuously adding cement, fly ash, mineral powder, and silica fume and continuing to mix. At the same time, the liquid admixture obtained in Example 2 is added to water and then added to the mixture together with the water, and the mixture is stirred for another 35 seconds.

[0050] In addition, as shown in Tables 1 and 2, FZ-1 C60 and FZ-1 C80 are commonly used powder admixture systems on the market (FZ-SYS from Shandong Fangzhou New Materials Co., Ltd.), serving as control groups; JT-2 C60 and JT-2 C80 are liquid admixture systems of the present invention, serving as experimental groups to verify the comprehensive performance effect of the liquid admixture of the present invention under different strength grades.

[0051] The testing was conducted according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete" and GB / T50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Concrete". The results are shown in Table 3. Concrete prepared using the liquid admixture of this invention exhibits good workability, strength, impermeability, and carbonation resistance.

[0052] Table 1. Mix proportions for trial concrete mixes of FZ-1 C60 and FZ-1 C80 special powder admixtures for mine shafts. Note: "\" indicates that no text is added.

[0053] Table 2. Mix Proportions for Mine Shaft-Specific Liquid Admixtures JT-2 C60 and JT-2 C80 in Concrete Trial Mix Design Note: "\" indicates that no text is added.

[0054] Table 3. Comprehensive performance effects of concrete with different admixtures at different strength grades The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-strength concrete liquid admixture specifically for mine shafts, characterized in that, It is composed of the following components in parts by weight: 20-70 parts by weight of water-reducing agent, 1-4 parts by weight of water-based nano crack-resistant and seepage-proof agent, 1-6 parts by weight of triisopropanolamine, 3-7 parts by weight of anhydrous sodium sulfate, 0.05-0.2 parts by weight of defoamer, and 30-70 parts by weight of water.

2. The high-strength concrete liquid admixture for mine shafts according to claim 1, characterized in that, It is composed of the following components in parts by weight: 26 parts water-reducing agent, 4 parts triisopropanolamine, 4 parts water-based nano crack-resistant and seepage-proof agent, 3 parts anhydrous sodium sulfate, 0.1 parts defoamer, and 63 parts water.

3. The high-strength concrete liquid admixture for mine shafts according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent; the defoamer is a polyether defoamer.

4. The high-strength concrete liquid admixture for mine shafts according to claim 1, characterized in that, The triisopropanolamine has a purity of 99%, and the anhydrous sodium sulfate has a purity of 99%.

5. A method for preparing a liquid admixture for high-strength concrete used in mine shafts as described in claim 1, characterized in that, Includes the following steps: (1) Add water to the reaction apparatus and turn on the stirrer; (2) Add water-reducing agent, water-based nano anti-crack and seepage-proof agent, triisopropanolamine and defoamer to the reaction device in sequence; (3) Add anhydrous sodium sulfate into the reaction apparatus and continue stirring.

6. The preparation method of the high-strength concrete liquid admixture for mine shafts according to claim 5, characterized in that, The temperature of the reaction apparatus is controlled between 20 and 50°C.

7. The application of the high-strength concrete liquid admixture for mine shafts as described in claim 1 in the preparation of concrete for mine shafts, characterized in that, The liquid admixture is mixed with the mixing water and then added to the concrete mixture to prepare concrete with strength grades of C50 to C100.

8. The application of the high-strength concrete liquid admixture for mine shafts according to claim 7 in the preparation of concrete for mine shafts, characterized in that, The amount of the liquid admixture added during concrete preparation is 3-8% of the total weight of the concrete mixture.

9. The application of the high-strength concrete liquid admixture for mine shafts according to claim 7 in the preparation of concrete for mine shafts, characterized in that, The specific steps are as follows: Sand and gravel are added to the mixer and mixed evenly. Then cement, fly ash, mineral powder, and silica fume are added continuously and mixed again to obtain a concrete mixture. At the same time, according to the target strength grade of the concrete, liquid admixtures are mixed evenly with the mixing water, and the mixture is added to the mixer and mixed for a preset time.

10. The application of the high-strength concrete liquid admixture for mine shafts according to claim 7 in the preparation of concrete for mine shafts, characterized in that, Also includes: Collect quality test data of liquid admixtures, and determine the range of concrete strength grades corresponding to this batch of liquid admixtures based on the test data; Determine the target liquid admixture and its dosage based on the target strength grade of the concrete.

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