Cement-based grouting material based on periodic mesoporous organosilicon and preparation method thereof

Abstract

The invention aims to provide a cement-based grouting material based on periodic mesoporous organosilicon and a preparation method thereof, and the cement-based grouting material is prepared from 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 a polycarboxylic acid water reducing agent, 0.1-5 parts of sodium silicate, 0.5-1.5 parts of periodic mesoporous organosilicon and 0.1-2 parts of fumed silica. And 0.1 to 2 parts of glass fiber. By adopting the grouting material, the early mechanical property of the grouting material is improved, so that the grouting material has higher flowing water scouring resistance in the early stage.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a cement-based grouting material based on periodic mesoporous organosilicon and a preparation method thereof. Background Art

[0002] The problem of water leakage in underground structures is becoming increasingly prominent, seriously affecting the safety, applicability and durability of the structures. Among the methods for treating water leakage, grouting has made great progress and has been widely used. At present, common grouting materials can be divided into organic and inorganic materials. Organic waterproof grouting materials have the advantages of controllable setting time and good grouting properties, but factors such as high cost, low durability, pollution and high toxicity limit their application. Inorganic grouting materials, as the currently commonly used grouting materials, have unique advantages in engineering applications. Inorganic grouting materials are mainly represented by cement-based materials, whose raw materials are widely available, low in cost, and environmentally friendly and non-toxic. However, pure cement grouting materials have the problems of long setting time, many pores in the hardened grouting body, low stone retention ratio under high water pressure, poor early strength and insufficient durability, which cannot meet the increasingly complex needs of tunnel water leakage control. Summary of the Invention

[0003] The purpose of the present invention is to provide a cement-based grouting material based on periodic mesoporous organosilicon and a preparation method thereof, so as to improve the early mechanical properties of the grouting material and enable it to have a higher resistance to dynamic water scouring in the early stage.

[0004] The present 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 silicone is synthesized using triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane as synthetic raw materials, and the mass ratio of the F-127 polyether template, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane is 1:(2-4):(1-3):(1-3).

[0008] Furthermore, the following raw materials are included 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 silicone is 1:2.5:1.8:1.8.

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

[0012] The present invention also discloses a method for preparing the above-mentioned cement-based grouting material based on periodic mesoporous organosilicon, which is characterized by comprising the following steps:

[0013] Step 1: Weigh triblock copolymer F-127 and cetyltrimethylammonium bromide and dissolve them in aqueous ammonia to form a colorless, transparent solution; add tetraethyl silicate under stirring to form a white suspension at room temperature; stir to react; and add bis(triethoxysilyl)ethane dropwise to obtain a raw material mixture;

[0014] Step 2: The raw material mixture in step 1 is further treated under hydrothermal conditions at 98-102° C. for 24 hours, and then centrifuged at high speed. The solid is collected by filtration and washed several times to obtain a periodic mesoporous organosilicon finished material;

[0015] Step 3: mixing the periodic mesoporous organosilicon product prepared in step 2 with an ethanol aqueous solution containing concentrated HCl, and drying to obtain a white powdery periodic mesoporous organosilicon;

[0016] Step 4: weighing a polycarboxylate water-reducing agent, sodium silicate, fumed silica, glass fiber, and the periodic mesoporous organosilicon prepared in step 3, mixing and stirring to obtain a mixed auxiliary material;

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

[0018] The beneficial effects of the present invention are as follows: 1. Periodic mesoporous organosilicon is an organic-inorganic hybrid nanoporous silicon material with a spiral mesoporous structure and high hydrothermal stability; its special spiral mesoporous structure provides a large number of nucleation sites for cement hydration products, reduces the nucleation energy barrier of hydration products such as hydrated calcium silicate, ettringite, and calcium hydroxide, accelerates the precipitation process of hydration products, and accelerates the "dissolution-precipitation" quasi-equilibrium in the cement hydration induction period to move toward the precipitation direction, significantly improving the cement hydration rate, shortening the induction period, thereby shortening the setting time, and improving the early mechanical properties of the grouting material, so that it can have a high resistance to dynamic water erosion in the early stage. 2. Periodic mesoporous organosilicon has a one-dimensional tubular structure at the nanometer scale, and glass fiber has a one-dimensional needle-like structure at the micrometer scale. The two have a synergistic effect. After the grouting material hardens, the mechanical properties of the cement matrix are enhanced through the microscopic full-scale bridging reinforcement effect at the nanometer and micrometer levels. 3. Nano-scale fumed silica, periodic mesoporous organosilicon, and micron-scale glass fiber have different size levels and can grade and fill the voids formed by hydration cement particles, thereby optimizing the pore structure of the grouting material, reducing the porosity of the material, and improving its anti-permeability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the SEM image of the PMOs in Comparative Example 7;

[0020] Figure 2 is the SEM image of the PMOs in Comparative Example 6;

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

[0022] Figure 4 This is the SEM image of the PMOs in Example 1. DETAILED DESCRIPTION

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

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

[0025]

[0026] The periodic mesoporous silicone is synthesized using triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate, and bis(triethoxysilyl)ethane as synthetic raw materials, and 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 stands for cetyltrimethylammonium bromide; TEOS stands for tetraethyl silicate; and BTEE stands for bis(triethoxysilyl)ethane.

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

[0029] As a best 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 silicone is 1:2.5:1.8:1.8.

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

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

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

[0035] 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 to form a white suspension at room temperature. After stirring for 2 hours, slowly add bis(triethoxysilyl)ethane dropwise to obtain a raw material mixture. Room temperature refers to the temperature at which the periodic mesoporous organosilicon-modified cement-based grouting material is synthesized, that is, no heating device is required.

[0036] Step 2: The raw material mixture in step 1 is further treated under hydrothermal conditions at 98-102° C. for 24 hours, and then centrifuged at high speed. The solid is collected by filtration and washed several times with water and ethanol to obtain a periodic mesoporous organosilicon finished material;

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

[0038] Step 4: Weigh polycarboxylate water-reducing agent, sodium silicate, periodic mesoporous organosilicon, fumed silica, and glass fiber, mix and stir for 30 minutes to obtain a mixed auxiliary material;

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

[0040] In order to verify the method of the present invention, the following examples and comparative examples are provided, and the performance of the modified cement-based grouting materials in each example and comparative example is tested as follows:

[0041] According to GB18445-2012, the setting time, flexural strength, compressive strength and stone rate of the surface treatment-free cement-based coating used for tunnel leakage treatment were tested.

[0042] Table 1 Various embodiments and performance test results

[0043]

[0044]

[0045] Table 2 Comparative Examples and Performance Test Results

[0046]

[0047]

[0048] Comparing the performance test results of Examples 1-3 and Comparative Examples 1-2, it can be seen that, because sulfoaluminate cement rapidly generates needle-rod-shaped ettringite after mixing, providing mechanical strength to the system, its addition effectively shortens the setting time of cement-based grouting materials, with the higher the addition amount, the more significant the effect. Without sulfoaluminate cement, the system setting time is too long, making it unsuitable for construction under dynamic water scouring conditions. Using only sulfoaluminate cement as the cementitious material results in a setting time that is too short, making grouting impossible.

[0049] Comparing the performance test results of Examples 1, 4-5, and Comparative Example 3 shows that in the early stages 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 and significantly increasing the cement hydration rate, thereby shortening the setting time. Furthermore, its nano-bridging effect can enhance the compressive resistance of the grouting material throughout its lifespan.

[0050] Comparing the performance test results of Examples 1, 4-5, and Comparative Example 3, we can see that in the early stages 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 and significantly increasing the cement hydration rate, thereby shortening the setting time. Furthermore, its nanoscopic bridging effect can improve the compressive resistance of the grouting material throughout its lifespan. Without the addition of periodic mesoporous organosilicon, the material's setting time is prolonged and its strength properties are reduced.

[0051] Comparing the performance test results of Example 1, Examples 4-9, and Comparative Examples 3-5, it can be seen that the fumed silica, PMOS, and glass fiber fully optimize the pore structure of the grouting material through multi-scale synergistic filling, reducing the material's porosity. The lack of any of these components will increase the material's porosity.

[0052] Comparing the performance test results of Examples 1, 4-5, 8-9, Comparative Examples 3, and 5, we can see that the nanoscale tubular structures of PMOS and the micron-scale needle-like structures of glass fibers synergistically provide full-scale bridging reinforcement, 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] Comparing the performance test results of Example 1, Examples 10-13, and Comparative Examples 6-7, it can be seen that by adjusting the raw material ratio of the PMOs, the aspect ratio of the PMOs can be effectively adjusted. The longer the aspect ratio of the PMOs, the more beneficial it is for improving the mechanical properties of the grouting material. When the raw material ratio is not within the scope of protection of this patent, the synthesized PMOs will be spherical or amorphous, and their nucleation site effect and nanoscopic bridging effect will not be effectively exerted.

[0054] like Figure 1-4 As shown, the morphology of PMOs synthesized with different mixing ratios is shown. 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 the process, amorphous PMOs are obtained. Figures 1-4 It can be seen that different mass ratios of raw materials give PMOs with different morphologies.

Claims

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

2. A cement-based grouting material based on periodic mesoporous organosilicon according to claim 1, characterized in that: Including the following raw materials by weight: The mass ratio of the triblock copolymer F-127, hexadecyltrimethylammonium bromide, tetraethyl silicate and bis(triethoxysilyl)ethane in the periodic mesoporous silicone is 1:2.5:1.8:1.

8.

3. A cement-based grouting material based on periodic mesoporous organosilicon according to claim 1 or 2, characterized in that: The periodic mesoporous organosilicon is 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 according to any one of claims 1 to 3, characterized in that: The steps include: Step 1: Weigh triblock copolymer F-127 and cetyltrimethylammonium bromide and dissolve them in aqueous ammonia to form a colorless, transparent solution; add tetraethyl silicate under stirring to form a white suspension at room temperature; stir to react; and add bis(triethoxysilyl)ethane dropwise to obtain a raw material mixture; Step 2: The raw material mixture in step 1 is further treated under hydrothermal conditions at 98-102° C. for 24 hours, and then centrifuged at high speed. The solid is collected by filtration and washed several times to obtain a periodic mesoporous organosilicon finished material; Step 3: mixing the periodic mesoporous organosilicon product prepared in step 2 with an ethanol aqueous solution containing concentrated HCl, and drying to obtain a white powdery periodic mesoporous organosilicon; Step 4: weighing a polycarboxylate water-reducing agent, sodium silicate, fumed silica, glass fiber, and the periodic mesoporous organosilicon prepared in step 3, mixing and stirring to obtain a mixed auxiliary material; Step 5: Weigh silicate cement, sulphoaluminate cement and fly ash, mix and stir to obtain a dry mixed powder; mix the dry mixed powder with the mixed auxiliary materials in step 4 to obtain a cement-based grouting material based on periodic mesoporous organosilicon.

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