A mine-used high-strength rapid-setting cement grouting material and a preparation method thereof

Abstract

The application discloses a mine-used high-strength rapid-setting cement grouting material and a preparation method thereof, and belongs to the technical field of mine repair materials. The technical scheme is as follows: the mine-used high-strength rapid-setting cement grouting material is composed of A material and B material; the A material comprises the following raw materials in parts by weight: 100 parts of sulphoaluminate cement clinker, 1.3-1.7 parts of building instant glue powder, 1.8-2.0 parts of water reducing agent, 10-20 parts of glass beads, 2.2-2.8 parts of strength agent and 0.1-0.3 parts of tartaric acid; the B material comprises the following raw materials in parts by weight: 40-78 parts of aluminate cement, 3-5 parts of calcium oxide, 0.2-0.7 parts of defoaming agent, 25-45 parts of gypsum and 1.1-1.5 parts of early strength agent. Through the optimized selection of components in the A material and the B material, the initial setting time of the cement grouting material is shortened, and the compressive strength of the cement grouting material reaches more than 30 MPa in one hour.

Description

Technical Field

[0001] This application relates to the field of mine emergency repair materials, and in particular to a high-strength, fast-setting cement grout for mining and its preparation method. Background Technology

[0002] High-strength, quick-setting cement grout is a special type of grouting material that combines high strength with rapid setting and hardening. This grout exhibits high fluidity, rapid setting, and high early strength, enabling it to reach its design strength in a short time and ensuring rapid structural stability. Therefore, quick-setting grout can be widely used in projects such as safety protection and reinforcement in mining operations, underground tunnels, and building wall solidification. It has broad applications in mineral resource development and the construction industry, particularly in projects requiring rapid hardening, where its low cost, short construction period, high efficiency, and significant economic benefits make it a valuable option.

[0003] Existing quick-setting grouts have a slow initial setting speed, usually requiring 2-5 hours, and the strength of the grout is low during initial setting, typically 15 MPa per hour. Commercially available high-strength quick-setting grouts (grouts that reach 30 MPa within 1 day are considered high-strength quick-setting grouts) have a strength of 20 MPa per hour, which is far from meeting the requirements for use in harsh environments. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, this application provides a high-strength quick-setting cement grout for mining and its preparation method. By optimizing the selection of components in material A and material B, the initial setting time of the cement grout is shortened and the compressive strength reaches more than 30 MPa after 1 hour.

[0005] The first aspect of this application is to provide a high-strength, quick-setting cement grouting material for mining, which adopts the following technical solution:

[0006] A high-strength, quick-setting cement grouting material for mining, composed of component A and component B;

[0007] Material A comprises the following raw materials in parts by weight: 100 parts of sulfoaluminate cement clinker, 1.3-1.7 parts of quick-dissolving building adhesive powder, 1.8-2.0 parts of water-reducing agent, 10-20 parts of glass microspheres, 2.2-2.8 parts of strength agent, and 0.1-0.3 parts of tartaric acid;

[0008] Material B comprises the following raw materials in parts by weight: 40-78 parts aluminate cement, 3-5 parts calcium oxide, 0.2-0.7 parts defoamer, 25-45 parts gypsum, and 1.1-1.5 parts early strength agent.

[0009] By adopting the above technical solution, this application achieves a balanced performance of rapid setting, high strength, micro-expansion, and high durability through the synergistic effect of the sulfoaluminate-aluminate dual gel system after mixing components A and B. The reason may be that the sulfoaluminate cement clinker in component A has a fast hydration rate, which can provide immediate strength. The gypsum in component B reacts with aluminate cement to form ettringite, which further accelerates setting. At the same time, the process of forming ettringite will produce an expansion effect, which can compensate for hardening shrinkage. Calcium oxide provides an alkaline environment for cement hydration and participates in hydration, promoting the formation of CSH gel and enhancing the early strength of the grout. Therefore, the setting time is further shortened after mixing components A and B. The strength of the grout can reach 30 MPa in one hour, which can effectively meet the needs of special situations (such as emergency rescue, mine reinforcement, bridge reinforcement, etc.). In order to avoid flash setting after mixing components A and B, this application adds tartaric acid to component A, thereby ensuring the operability of construction.

[0010] In addition, the quick-dissolving adhesive powder in Material A of this application can improve fluidity, prevent bleeding and segregation, and effectively ensure the construction performance of the grouting material.

[0011] In a preferred embodiment, the weight ratio of material A to material B is (1.17-1.26):1.

[0012] By adopting the above technical solution, when material A and material B are mixed in this weight ratio, the strength of the grout can be guaranteed, and the grout can also be made to set quickly.

[0013] In a preferred embodiment, the strength agent in material A includes one or both of sodium sulfate and bauxite.

[0014] In a preferred embodiment, the weight ratio of sodium sulfate to bauxite is (1.4-1.6):1.

[0015] By adopting the above technical solution, when the strength agent is composed of sodium sulfate and bauxite, the bauxite promotes the reaction of sodium sulfate with tricalcium aluminate in cement to form ettringite, which accelerates early cement hydration and improves the early strength of cement grout.

[0016] In a preferred embodiment, the strength agent in material B is one or both of calcium formate and lithium carbonate.

[0017] By adopting the above technical solution, lithium carbonate in the early strength agent reacts with aluminate minerals in cement to generate single-carbon hydrated aluminate. Under the same degree of hydration, it helps to increase the solid volume in cement paste, reduce the porosity of cement paste, and improve density. Moreover, lithium carbonate can significantly accelerate the hydration rate of cementitious materials and improve strength even at a low dosage. Furthermore, due to the small radius of lithium ions, they have a strong polarization effect, which can accelerate the destruction of the hydration protective film on the surface of cement particles and significantly shorten the cement hydration induction period.

[0018] Calcium formate can significantly accelerate the hydration reaction process of cement. After cement and water are mixed, the calcium ions in calcium formate can react with mineral components such as tricalcium silicate and dicalcium silicate in cement, promoting the dissolution of cement minerals and the formation of hydration products. This allows the cement slurry to reach higher strength in a shorter time, shortens the setting time of cement, and improves the strength of the cement slurry.

[0019] In a preferred embodiment, the amount of lithium carbonate added is 10% of the weight of calcium formate.

[0020] In a preferred embodiment, 0.01-0.03 parts by weight of hydroxypropyl starch ether are also added to material B.

[0021] By adopting the above technical solution, after adding hydroxypropyl starch ether to component B, it can form a strong bond with cement hydration products, thereby improving the bonding strength and strength of cement grout.

[0022] In a preferred embodiment, the glass microspheres have a particle size of 200 mesh.

[0023] The second aspect of this application is to provide a method for preparing high-strength quick-setting cement grout for mining as described above, comprising the following steps: preparing material A by mixing sulfoaluminate cement clinker, building quick-setting adhesive powder, water-reducing agent, glass microspheres, strength agent and tartaric acid in proportion to weight, adding water and stirring for 1-2 minutes.

[0024] To prepare component B, mix aluminate cement, calcium oxide, defoamer, gypsum, and early strength agent evenly according to their weight proportions, add water, stir for 1-2 minutes, and then mix component A and component B to obtain cement grouting material.

[0025] By adopting the above technical solution, preparing materials A and B separately before adding water ensures uniform mixing of the substances without interference. Furthermore, the strength obtained by mixing the materials separately after adding water is superior to that obtained by mixing the A and B powders separately before adding water. This is because, when water is added to materials A and B separately first, the sulfoaluminate cement clinker in material A first forms CSH gel and a small amount of ettringite, resulting in a more uniform structure. In material B, the aluminate cement reacts with gypsum to form ettringite. When the pre-activated A and B materials are mixed, the reaction between the remaining active components is more gradual, and the hydration products are more evenly distributed. However, when the two powders are mixed first and then water is added, the sulfoaluminate cement clinker reacts with gypsum to form ettringite. When aluminate cement clinker and aluminate cement come into direct contact, the active components of the two cements react instantly upon the addition of water, generating a large amount of ettringite and alumina gel. This leads to a concentrated release of hydration heat, creating a temperature gradient and inducing microcracks. Furthermore, the localized accumulation of the generated ettringite hinders subsequent hydration channels, affecting the completeness of cement hydration and significantly reducing the strength of the cement grout. The maximum strength after 1 hour is only 24 MPa. Therefore, mixing powders A and B separately with water not only ensures that both powders A and B achieve pre-activation but also effectively shortens the initial setting time of the cement grout and increases its compressive strength after 1 hour.

[0026] In a preferred embodiment, the water-to-binder ratio of both material A and material B is 0.25.

[0027] In summary, this application has the following beneficial effects:

[0028] 1. This application achieves a balanced performance of rapid setting, high strength, micro-expansion and high durability through the synergistic effect of the sulfoaluminate-aluminate dual gel system, which can effectively meet the strength requirements under special conditions.

[0029] 2. The combination of the strength agent and the early strength agent in this application not only effectively improves the compressive strength of the cement grout after 1 hour, but also effectively shortens the initial setting time of the cement grout. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments. All reagents, unless otherwise specified, are commercially available conventional reagent products.

[0031] In a preferred embodiment, a high-strength, quick-setting cement grout for mining is composed of component A and component B.

[0032] Material A comprises the following raw materials in parts by weight: 100 parts of sulfoaluminate cement clinker, 1.3-1.7 parts of quick-dissolving building adhesive powder, 1.8-2.0 parts of water-reducing agent, 10-20 parts of glass microspheres, 2.2-2.8 parts of strength agent, and 0.1-0.3 parts of tartaric acid;

[0033] Material B comprises the following raw materials in parts by weight: 40-78 parts aluminate cement, 3-5 parts calcium oxide, 0.2-0.7 parts defoamer, 25-45 parts gypsum, and 1.1-1.5 parts early strength agent.

[0034] In a preferred embodiment, the weight ratio of material A to material B is (1.17-1.26):1.

[0035] In a preferred embodiment, the strength agent in material A includes one or both of sodium sulfate and bauxite.

[0036] In a preferred embodiment, the weight ratio of sodium sulfate to bauxite is (1.4-1.6):1.

[0037] In a preferred embodiment, the strength agent in material B is one or both of calcium formate and lithium carbonate.

[0038] In a preferred embodiment, the amount of lithium carbonate added is 10% of the weight of calcium formate.

[0039] In a preferred embodiment, 0.01-0.03 parts by weight of hydroxypropyl starch ether are also added to material B.

[0040] In a preferred embodiment, the glass microspheres have a particle size of 200 mesh.

[0041] The second aspect of this application is to provide a method for preparing high-strength quick-setting cement grout for mining as described above, comprising the following steps: preparing material A by mixing sulfoaluminate cement clinker, building quick-setting adhesive powder, water-reducing agent, glass microspheres, strength agent and tartaric acid in proportion to weight, adding water and stirring for 1-2 minutes.

[0042] To prepare component B, mix aluminate cement, calcium oxide, defoamer, gypsum, and early strength agent evenly according to their weight proportions, add water, stir for 1-2 minutes, and then mix component A and component B to obtain cement grouting material.

[0043] In a preferred embodiment, the water-to-binder ratio of both material A and material B is 0.25.

[0044] In the embodiments and comparative examples of this application, a high-performance polycarboxylate superplasticizer is used, with a water reduction rate of 20%.

[0045] Example 1

[0046] A method for preparing a high-strength, quick-setting cement grout for mining includes the following steps:

[0047] Prepare ingredient A by mixing 10 kg of sulfoaluminate cement clinker, 0.13 kg of quick-dissolving building adhesive powder, 0.18 kg of water-reducing agent, 1 kg of 200-mesh glass microspheres, 0.22 kg of strength agent, and 0.01 kg of tartaric acid evenly; the strength agent is composed of sodium sulfate and bauxite in a weight ratio of 1.4:1.

[0048] Prepare component B by mixing 4 kg of aluminate cement, 0.3 kg of calcium oxide, 0.02 kg of silicone defoamer, 2.5 kg of gypsum, and 0.11 kg of early strength agent evenly. The early strength agent consists of lithium carbonate and calcium formate, and the amount of lithium carbonate added is 10% of the weight of calcium formate.

[0049] Mix component A and component B at a weight ratio of 1.17:1. Then add water to component A and component B separately, with a water-cement ratio of 0.25 for both. Stir component A and component B separately for 1-2 minutes, then mix them together to obtain cement grouting material.

[0050] Example 2

[0051] A method for preparing a high-strength, quick-setting cement grout for mining includes the following steps:

[0052] Prepare ingredient A by mixing 10 kg of sulfoaluminate cement clinker, 0.15 kg of quick-dissolving building adhesive powder, 0.19 kg of water-reducing agent, 1.5 kg of glass microspheres with a particle size of 200 mesh, 0.25 kg of strength agent and 0.02 kg of tartaric acid evenly. The strength agent is composed of sodium sulfate and bauxite in a weight ratio of 1.5:1.

[0053] Prepare component B by mixing 5.6 kg of aluminate cement, 0.4 kg of calcium oxide, 0.05 kg of silicone defoamer, 3.5 kg of gypsum, and 0.13 kg of early strength agent evenly. The early strength agent consists of lithium carbonate and calcium formate, and the amount of lithium carbonate added is 10% of the weight of calcium formate.

[0054] Mix component A and component B at a weight ratio of 1.17:1. Then add water to component A and component B separately, with a water-cement ratio of 0.25 for both. Stir component A and component B separately for 1-2 minutes, then mix them together to obtain cement grouting material.

[0055] Example 3

[0056] A method for preparing a high-strength, quick-setting cement grout for mining includes the following steps:

[0057] Prepare ingredient A by mixing 10 kg of sulfoaluminate cement clinker, 0.17 kg of quick-dissolving building adhesive powder, 0.2 kg of water-reducing agent, 2 kg of glass microspheres with a particle size of 200 mesh, 0.28 kg of strength agent and 0.03 kg of tartaric acid evenly. The strength agent is composed of sodium sulfate and bauxite in a weight ratio of 1.6:1.

[0058] Prepare component B by mixing 7.8 kg of aluminate cement, 0.5 kg of calcium oxide, 0.07 kg of organosilicon defoamer, 4.5 kg of gypsum, and 0.15 kg of early strength agent evenly. The early strength agent consists of lithium carbonate and calcium formate, and the amount of lithium carbonate added is 10% of the weight of calcium formate.

[0059] Mix component A and component B at a weight ratio of 1.17:1. Then add water to component A and component B separately, with a water-cement ratio of 0.25 for both. Stir component A and component B separately for 1-2 minutes, then mix them together to obtain cement grouting material.

[0060] Example 4

[0061] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that component A and component B are mixed in a weight ratio of 1.26:1, while all other aspects are the same as in Example 2.

[0062] Example 5

[0063] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that 0.001 kg of hydroxypropyl starch ether is added to component B, while the rest are the same as in Example 2.

[0064] Example 6

[0065] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that 0.003 kg of hydroxypropyl starch ether is added to component B, while the rest are the same as in Example 2.

[0066] Example 7

[0067] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that the strength agent in material A is only sodium sulfate, while the others are the same as in Example 2.

[0068] Example 8

[0069] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that the strength agent in material A is only bauxite, while the others are the same as in Example 2.

[0070] Example 9

[0071] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that the early-strength agent in component B is only calcium formate, while the others are the same as in Example 2.

[0072] Example 10

[0073] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that the early-strength agent in component B is only lithium carbonate, while the others are the same as in Example 2.

[0074] Comparative Example 1

[0075] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that the A component lacks a strength agent, while the rest is the same as in Example 2.

[0076] Comparative Example 2

[0077] A method for preparing a high-strength, quick-setting cement grout for mining differs from Example 2 in that material B lacks an early-strength agent, while the rest is the same as in Example 2.

[0078] Performance testing

[0079] The setting time and compressive strength of the cement grouting materials obtained in the above embodiments and comparative examples were tested, and the test results are shown in Table 1. The compressive strength was tested in accordance with the relevant provisions of GB / T50448-2015 "Technical Specification for Application of Cement-based Grouting".

[0080] Table 1. Test Results of Cement Grouting Material

[0081] project Initial setting time / min 1-hour compressive strength / MPa 1-day compressive strength / MPa Example 1 3.5 31.2 54.9 Example 2 3.2 33.5 55.8 Example 3 3.1 32.6 55.7 Example 4 3.8 31.8 55.2 Example 5 3.2 35.8 56.3 Example 6 3.3 35.5 56.2 Example 7 4.6 28.6 54.3 Example 8 4.7 29.2 54.1 Example 9 6.5 27.4 53.2 Example 10 5.9 28.2 53.8 Comparative Example 1 8.2 23.6 48.6 Comparative Example 2 9.5 21.3 47.2

[0082] As can be seen from Table 1 above:

[0083] The initial setting time of the cement grouting materials obtained in Examples 1-4 of this application is all within 4 minutes, and the compressive strength after 1 hour is all above 30 MPa. This indicates that the cement grouting materials obtained in this application can achieve the effect of rapid setting and high strength, thus meeting the requirements for use in harsh environments.

[0084] Compared with Example 2, when hydroxypropyl starch ether was added to the cement grout, the initial setting time of the cement grout obtained in Examples 5-6 was slightly shorter than that in Example 2, while the compressive strength at 1 hour was significantly higher than that in Example 2, indicating that the addition of hydroxypropyl starch ether can further enhance the early strength of the cement grout.

[0085] Compared with Example 2, when only sodium sulfate or bauxite is used as the strength agent, the initial setting time of the cement grout obtained in Examples 7-8 is significantly increased compared with Example 2. At the same time, the strength of the cement grout after 1 hour is significantly reduced compared with Example 2. This indicates that when only one of sodium sulfate or bauxite is used as the strength agent, the amount of ettringite generated in the grout will be reduced, thereby reducing the strength of the cement grout. It also prolongs the cement hydration time, which in turn prolongs the initial setting time.

[0086] Compared with Example 2, when only calcium formate or lithium carbonate is used as the early strength agent, the initial setting time of the cement grout obtained in Examples 9-10 is significantly higher than that in Example 2, and the compressive strength at 1 hour is significantly lower than that in Example 2. This is because both lithium carbonate and calcium formate promote cement hydration, thereby shortening the setting time of the cement grout. Therefore, when only calcium formate or lithium carbonate is used, the setting time in Examples 9-10 is prolonged and the compressive strength is reduced.

[0087] Compared with Example 2, when the cement grout lacked the strength agent and the early strength agent, the initial setting time of the cement grout obtained in Comparative Examples 1-2 was much longer than that in Example 2, while the 1-hour compressive strength was much shorter than that in Example 2. This shows that the combined use of the strength agent and the early strength agent not only improved the compressive strength of the cement grout, but also greatly shortened the setting time of the cement grout, effectively meeting the requirements for the use of cement grout in harsh environments.

[0088] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-strength, quick-setting cement grout for mining, characterized in that: It is composed of material A and material B, wherein the weight ratio of material A to material B is (1.17-1.26):1; Material A comprises the following raw materials in parts by weight: 100 parts of sulfoaluminate cement clinker, 1.3-1.7 parts of quick-dissolving building adhesive powder, 1.8-2.0 parts of water-reducing agent, 10-20 parts of glass microspheres, 2.2-2.8 parts of strength agent, and 0.1-0.3 parts of tartaric acid. The strength agent comprises sodium sulfate and bauxite in a weight ratio of (1.4-1.6):

1. Material B comprises the following raw materials in parts by weight: 40-78 parts aluminate cement, 3-5 parts calcium oxide, 0.2-0.7 parts defoamer, 25-45 parts gypsum, 1.1-1.5 parts early strength agent, and 0.01-0.03 parts hydroxypropyl starch ether. The early strength agent is composed of calcium formate and lithium carbonate, and the amount of lithium carbonate added is 10% of the weight of calcium formate.

2. The high-strength, quick-setting cement grouting material for mining according to claim 1, characterized in that: The glass microspheres have a particle size of 200 mesh.

3. A method for preparing a high-strength, quick-setting cement grout for mining as described in any one of claims 1-2, characterized in that, The process includes the following steps: Prepare material A by mixing sulfoaluminate cement clinker, quick-dissolving building adhesive powder, water-reducing agent, glass microspheres, strength agent and tartaric acid according to the weight parts, then add water and stir for 1-2 minutes. To prepare component B, mix aluminate cement, calcium oxide, defoamer, gypsum, and early strength agent evenly according to their weight proportions, add water, stir for 1-2 minutes, and then mix component A and component B to obtain cement grouting material.

4. The preparation method of a high-strength, quick-setting cement grout for mining according to claim 3, characterized in that: The water-to-binder ratio of both component A and component B is 0.25.