A periodic mesoporous organosilica-based cement-based grouting material and a preparation method thereof

Abstract

The application discloses a periodic mesoporous organic silicon-based cement-based grouting material and a preparation method thereof. The grouting material comprises the following raw materials in parts by mass: 60-75 parts of Portland cement, 5-20 parts of sulphoaluminate cement, 5-20 parts of fly ash, 0.1-1 part of polycarboxylic acid water reducer, 0.1-5 parts of sodium silicate, 0.5-1.5 parts of periodic mesoporous organic silicon, 0.1-2 parts of fumed silica and 0.1-2 parts of glass fiber. The grouting material can improve the early mechanical property of the grouting material and enable the grouting material to have high resistance to water scouring in the early stage.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a cement-based grouting material based on periodic mesoporous organosilicon and its preparation method. Background Technology

[0002] Water leakage in underground structures is becoming increasingly prominent, seriously affecting structural safety, applicability, and durability. Among methods for treating water leakage, grouting has seen significant development and widespread application. Currently, common grouting materials can be divided into organic and inorganic materials. Organic waterproof grouting materials have advantages such as controllable setting time and good injectability, but their application is limited by high cost, low durability, pollution, and high toxicity. Inorganic grouting materials, as commonly used grouting materials, have unique advantages in engineering applications. Cement-based materials are the main representative of inorganic grouting materials, with widely available raw materials, low cost, and environmental friendliness. However, pure cement grouting materials suffer from long setting time, numerous pores within the hardened grout, low stone retention ratio under high water pressure, poor early strength, and insufficient durability, failing to meet the increasingly complex needs of tunnel water leakage control. Summary of the Invention

[0003] The purpose of this invention is to provide a cement-based grouting material based on periodic mesoporous organosilicon and its preparation method, thereby improving the early mechanical properties of the grouting material and enabling it to have a high resistance to dynamic water erosion in the early stage.

[0004] This invention adopts the following technical solution: a cement-based grouting material based on periodic mesoporous organosilicon, comprising the following raw materials in parts by weight:

[0005]

[0006]

[0007] The periodic mesoporous organosilicon is synthesized using triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane as raw materials. The mass ratio of F-127 polyether template, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane is 1:(2-4):(1-3):(1-3).

[0008] Furthermore, it includes the following raw materials in parts by weight:

[0009]

[0010] The mass ratio of the triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane in the periodic mesoporous organosilicon is 1:2.5:1.8:1.8.

[0011] Furthermore, this periodic mesoporous organosilicon has a one-dimensional needle-like structure with an aspect ratio of 4.3-9.8.

[0012] This invention also discloses a method for preparing a cement-based grouting material based on periodic mesoporous organosilicon, characterized by comprising the following steps:

[0013] Step 1: Weigh the triblock copolymer F-127 and hexadecyltrimethylammonium bromide and dissolve them in ammonia water to form a colorless and transparent solution. Add tetraethyl silicate under stirring conditions to form a white suspension at room temperature. Stir the reaction and add bis(triethoxysilyl)ethane dropwise to obtain the raw material mixture.

[0014] Step 2: After further treating the raw material mixture from Step 1 under hydrothermal conditions at 98-102℃ for 24 hours, centrifuge at high speed, filter and collect the solid, wash several times to obtain the periodic mesoporous organosilicon finished product.

[0015] Step 3: Mix the periodic mesoporous organosilicon product from Step 2 with an ethanol aqueous solution containing concentrated HCl, and dry to obtain a white powdery periodic mesoporous organosilicon.

[0016] Step 4: Weigh out polycarboxylate superplasticizer, sodium silicate, fumed silica, glass fiber, and the periodic mesoporous organosilicon from Step 3, mix and stir to obtain a mixed auxiliary material;

[0017] Step 5: Weigh silicate cement, sulfoaluminate cement, and fly ash, mix and stir to obtain dry-mixed powder; mix the dry-mixed powder with the mixed auxiliary materials in Step 4 to obtain cement-based grouting material based on periodic mesoporous organosilicon.

[0018] The beneficial effects of this invention are as follows: 1. Periodic mesoporous organosilicon is an organic-inorganic hybrid nanoporous silicon material with a helical mesoporous structure and high hydrothermal stability. Its special helical mesoporous structure provides a large number of nucleation sites for cement hydration products, reduces the nucleation energy barrier of hydration products such as calcium silicate hydrate, ettringite, and calcium hydroxide, accelerates the precipitation process of hydration products, and accelerates the shift of the "dissolution-precipitation" quasi-equilibrium during the cement hydration induction period towards precipitation, significantly increasing the cement hydration rate, shortening the induction period, thereby shortening the setting time, improving the early mechanical properties of the grouting material, and enabling it to have high resistance to dynamic water erosion in the early stage. 2. Periodic mesoporous organosilicon has a nanoscale one-dimensional tubular structure, and glass fiber has a micrometer-scale one-dimensional needle-like structure. The two have a synergistic effect. After the grouting material hardens, the mechanical properties of the cement matrix are enhanced through the nano- and micrometer-level full-scale micro-bridging reinforcement. 3. Nanoscale fumed silica, periodic mesoporous organosilicon, and micron-sized glass fibers have different size levels, which can fill the voids formed by hydrated cement particles in a graded manner, optimize the pore structure of the grouting material, reduce the porosity of the material, and improve its impermeability and durability. Attached Figure Description

[0019] Figure 1 SEM images of PMOs in Comparative Example 7;

[0020] Figure 2 SEM images of PMOs in Comparative Example 6;

[0021] Figure 3 SEM images of the PMOs in Example 11;

[0022] Figure 4 This is a SEM image of the PMOs in Example 1. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention discloses a periodic mesoporous organosilicone modified cement-based grouting material, comprising the following raw materials in parts by weight:

[0025]

[0026] The periodic mesoporous organosilicon is synthesized using triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane as raw materials. The mass ratio of the triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane is 1:(2-4):(1-3):(1-3).

[0027] CTAB represents hexadecyltrimethylammonium bromide; TEOS tetraethyl silicate; BTEE represents bis(triethoxysilyl)ethane.

[0028] The aforementioned periodic mesoporous organosilicon has a one-dimensional needle-like structure with an aspect ratio of 4.3-9.8.

[0029] As a preferred embodiment, it is as follows:

[0030]

[0031] The mass ratio of the triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane in the periodic mesoporous organosilicon is 1:2.5:1.8:1.8.

[0032] The specifications of the above silicate cement are as follows: D90≤50μm, D50≤20μm.

[0033] The average particle size of this fumed silica is 200-600 nm.

[0034] The preparation method of the aforementioned periodic mesoporous organosilicone modified cement-based grouting material is as follows:

[0035] Step 1: Weigh out triblock copolymer F-127 and hexadecyltrimethylammonium bromide and dissolve them in ammonia water to form a colorless and transparent solution. Add tetraethyl silicate under stirring conditions to form a white suspension at room temperature. After stirring for 2 hours, slowly add bis(triethoxysilyl)ethane to obtain the raw material mixture. Room temperature refers to the temperature at which this periodic mesoporous organosilicon modified cement-based grouting material is synthesized, i.e., no heating device is required.

[0036] Step 2: After further treating the raw material mixture from Step 1 under hydrothermal conditions at 98-102℃ for 24 hours, centrifuge at high speed, filter and collect the solid, and wash it several times with water and ethanol to obtain the periodic mesoporous organosilicon finished product.

[0037] Step 3: Mix the periodic mesoporous organosilicon product from Step 2 with an ethanol aqueous solution containing concentrated HCl for 6 hours, and then dry to obtain a white powdery periodic mesoporous organosilicon.

[0038] Step 4: Weigh out polycarboxylate superplasticizer, sodium silicate, periodic mesoporous organosilicon, fumed silica, and glass fiber, mix and stir for 30 minutes to obtain mixed auxiliary materials;

[0039] Step 5: Weigh silicate cement, sulfoaluminate cement, and fly ash, mix and stir for 30 minutes to obtain dry-mixed powder; mix the dry-mixed powder with the mixed auxiliary materials in Step 4 for 30 minutes to obtain cement-based grouting material based on periodic mesoporous organosilicon.

[0040] To verify the method in this invention, the following embodiments and comparative examples are provided, and the performance of the modified cement-based grouting materials in each embodiment and comparative example is tested as follows:

[0041] The setting time, flexural strength, compressive strength, and stone formation rate of cement-based coatings that do not require substrate treatment for tunnel water leakage control were tested according to GB18445-2012.

[0042] Table 1. Results of each embodiment and performance test.

[0043]

[0044]

[0045] Table 2. Comparative Examples and Performance Test Results

[0046]

[0047]

[0048] Comparative results of performance tests in Examples 1-3 and Comparative Examples 1-2 show that sulfoaluminate cement can rapidly generate needle-like ettringite after mixing, providing mechanical strength to the system. Therefore, its addition can effectively shorten the setting time of cement-based grouting materials, and the higher the dosage, the more significant the effect. Without the addition of sulfoaluminate cement, the setting time of the system is too long, making it unsuitable for construction under conditions of flowing water scouring; using sulfoaluminate cement entirely as a cementitious material results in a setting time that is too short, making grouting construction impossible.

[0049] Comparative analysis of the performance test results of Examples 1, 4-5, and Comparative Example 3 shows that in the early stage of hydration, the unique helical mesoporous structure of PMOs provides a large number of nucleation sites for cement hydration products, accelerating the precipitation process of hydration products, significantly increasing the cement hydration rate, and thus shortening the setting time. Simultaneously, its nano-scale bridging effect can improve the compressive strength of the grouting material throughout its entire lifespan.

[0050] Comparing the performance test results of Examples 1, 4-5, and Comparative Example 3, it can be seen that in the early stage of hydration, the unique helical mesoporous structure of PMOs provides a large number of nucleation sites for cement hydration products, accelerating the precipitation process of cement hydration products, significantly increasing the cement hydration rate, and thus shortening the setting time. Simultaneously, its nano-bridge effect can improve the compressive strength of the grouting material throughout its entire lifespan. Without the addition of periodic mesoporous organosilicon, the setting time of the material is prolonged, and its strength properties decrease.

[0051] Comparing the performance test results of Examples 1, 4-9, and 3-5, it can be seen that fumed silica, PMOS, and glass fiber, through multi-scale synergistic filling, effectively optimize the pore structure of the grouting material and reduce its porosity. The absence of any one of these components will increase the porosity of the material.

[0052] Comparing the performance test results of Examples 1, 4-5, 8-9, 3, and 5, it can be seen that the PMOS nanoscale tubular structure and the glass fiber micron-scale needle structure work synergistically to achieve full-scale bridging reinforcement, thereby enhancing the mechanical properties of the cement matrix. The absence of either component will result in a decrease in the mechanical properties of the material.

[0053] Comparative analysis of the performance test results of Examples 1, 10-13, and 6-7 shows that adjusting the ratio of the synthetic raw materials for PMOs can effectively regulate their aspect ratio. A longer aspect ratio in PMOs is more beneficial for improving the mechanical properties of the grouting material. When the ratio of the synthetic raw materials is outside the scope of this patent, the synthesized PMOs will be spherical or amorphous, failing to effectively exert their nucleation site effect and nano-bridge effect.

[0054] like Figure 1-4 The image shows the morphology of PMOs synthesized with different mixing ratios. Figure 1 The aspect ratio is 1. Figure 3 The aspect ratio is 4.3. Figure 4 The aspect ratio is 9.8. Figure 2 In this process, amorphous PMOs are obtained. (From...) Figures 1-4 It can be seen that different mass ratios of raw materials result in PMOs with different morphologies.

Claims

1. A periodic mesoporous organosilica-based cementitious grout material, characterized in that, The raw materials include the following parts by weight: The periodic mesoporous organosilicon is synthesized using triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane as raw materials. The mass ratio of F-127 polyether template, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane is 1:(2-4):(1-3):(1-3).

2. A periodic mesoporous organosilica-based cementitious grout material according to claim 1, wherein, The raw materials include the following parts by weight: The mass ratio of the triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane in the periodic mesoporous organosilicon is 1:2.5:1.8:1.

8.

3. A cement-based grouting material based on periodic mesoporous organosilicon as described in claim 1 or 2, characterized in that, The periodic mesoporous organosilicon has a one-dimensional needle-like structure with an aspect ratio of 4.3-9.

8.

4. A method for preparing a cement-based grouting material based on periodic mesoporous organosilicon as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Weigh the triblock copolymer F-127 and hexadecyltrimethylammonium bromide and dissolve them in ammonia water to form a colorless and transparent solution. Add tetraethyl silicate under stirring conditions to form a white suspension at room temperature. Stir the reaction and add bis(triethoxysilyl)ethane dropwise to obtain the raw material mixture. Step 2: After further treating the raw material mixture from Step 1 under hydrothermal conditions at 98-102℃ for 24 hours, centrifuge at high speed, filter and collect the solid, wash several times to obtain the periodic mesoporous organosilicon finished product. Step 3: Mix the periodic mesoporous organosilicon product from Step 2 with an ethanol aqueous solution containing concentrated HCl, and dry to obtain a white powdery periodic mesoporous organosilicon. Step 4: Weigh out polycarboxylate superplasticizer, sodium silicate, fumed silica, glass fiber, and the periodic mesoporous organosilicon from Step 3, mix and stir to obtain a mixed auxiliary material; Step 5: Weigh silicate cement, sulfoaluminate cement, and fly ash, mix and stir to obtain dry-mixed powder; mix the dry-mixed powder with the mixed auxiliary materials in Step 4 to obtain cement-based grouting material based on periodic mesoporous organosilicon.

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