A cement-based shield synchronous grouting material and its preparation method

Abstract

This application relates to the field of cement, and specifically discloses a cement-based shield synchronous grouting material and a preparation method thereof. A cement-based shield synchronous grouting material comprises the following raw materials in parts by weight: 170 - 190 parts of cement, 760 - 780 parts of sand, 240 - 260 parts of fly ash, 50 - 60 parts of bentonite, 330 - 370 parts of water, and 0.5 - 2 parts of an air-entraining agent, wherein the air-entraining agent comprises alpha-olefin sulfonate and coconut oil amide succinate. The cement-based shield synchronous grouting material prepared in this application has the advantages of good fluidity, large gas content, low cement output, good compressive strength, and small consistency loss over time.

Description

Technical Field

[0001] The present application relates to the field of cement, and more specifically, it relates to a cement-based shield synchronous grouting material and a preparation method thereof. Background Art

[0002] With the continuous development and improvement of infrastructure construction in China, there are more and more projects for building railway tunnels, highway tunnels, and municipal tunnels using the shield method. To control the ground settlement caused during shield tunneling and protect adjacent existing buildings and structures, during the shield machine tunneling process, the excavation diameter of the cutter head is about 100 - 140 mm larger than the outer diameter of the segment, forming an annular gap between the two. During the tunneling process, synchronous grouting is required for filling. Synchronous grouting materials are major material consumptions in shield tunnel projects. Currently, cement-based mortar is mostly used as the synchronous grouting material for shield tunnels.

[0003] In the context of large-scale infrastructure construction, the demand for cement materials in projects is huge. Traditional cement-based synchronous grouting materials for shield tunnels consume a large amount of cementitious materials during use. Summary of the Invention

[0004] In order to reduce the amount of cement used in the synchronous grouting material during the shield process, the present application provides a cement-based shield synchronous grouting material.

[0005] In the first aspect, the present application provides a cement-based shield synchronous grouting material, adopting the following technical solution:

[0006] A cement-based shield synchronous grouting material, comprising the following raw materials in parts by weight: 170 - 190 parts of cement, 760 - 780 parts of sand, 240 - 260 parts of fly ash, 50 - 60 parts of bentonite, 330 - 370 parts of water, and 0.5 - 2 parts of an air-entraining agent, wherein the air-entraining agent comprises α-olefin sulfonate and coconut oil amide succinate.

[0007] By adopting the above technical solution, the present application introduces an air-entraining agent into the cement-based shield synchronous grouting material. The addition of the air-entraining agent introduces a large number of non-continuous tiny closed air bubbles into the fresh slurry. The existence of the tiny air bubbles plays a rolling ball effect in the slurry, improving the fluidity of the slurry and reducing the density of the synchronous grouting material. Therefore, the amount of cement used in the same volume of grouting material is reduced, thereby reducing the carbon emissions generated by consuming cement; in addition, since the segments are wrapped by the grouting slurry, during the construction process of shield tunnels, the overall or partial floating of the segment lining often occurs, ultimately leading to phenomena such as segment misalignment, cracks, and even axis deviation. Due to the addition of the air-entraining agent, the density of the slurry is reduced, so the situation of segment floating is well solved;

[0008] This application uses sodium α-olefin sulfonate and coconut oil amide succinate as air-entraining agents, which can cooperate with each other to effectively reduce the surface tension of water, generate a very large number of stable micro-bubbles, effectively reduce the density of the grouting slurry, save cement, and the air-entraining agents in this application are rich in anions. After being incorporated with cement, sand and water, the cement particles immediately adsorb anions and carry negative charges, making the water around the cement particles polar. The same-sex ions repel each other, thus preventing the adjacent ions of the cement particles from approaching each other, achieving the effects of dispersion and separation, improving the adsorption and diffusion ability of the cement particles, thereby inhibiting the generation of aggregates in the cement mortar, increasing the contact area between the cement particles and water, and enabling the cement particles to be fully hydrolyzed and hydrated. At the same time, during the diffusion process of the cement particles, the free water surrounded by the aggregates is released, and the cement mortar changes from a reticulated aggregate structure to a sol structure, making the mortar have good water retention and viscosity, thereby improving the fluidity and workability of the mortar. In addition, due to the addition of the air-entraining agent, the density of the grouting slurry decreases, and at the same time the compressive strength of the grouting slurry after curing also decreases. However, since this application uses sodium α-olefin sulfonate and coconut oil amide succinate as air-entraining agents, the cement particles are fully hydrolyzed and hydrated, compensating for the lost compressive strength, so that the grouting slurry using this application still has good compressive performance after curing.

[0009] Preferably, the mass ratio of the sodium α-olefin sulfonate to the coconut oil amide succinate is (3 - 5.7):1.

[0010] Preferably, the mass ratio of the sodium α-olefin sulfonate to the coconut oil amide succinate is 4:1.

[0011] By adopting the above technical solution, the sodium α-olefin sulfonate and the coconut oil amide succinate within the above mass range can better play a cooperative role, generating richer and more stable bubbles, which can further improve the fluidity of the grouting slurry, reduce the density of the grouting slurry, and reduce the cement usage.

[0012] Preferably, it further includes 0.3 - 0.5 parts by weight of an auxiliary agent, and the auxiliary agent includes glutaric acid and sodium carboxymethyl cellulose.

[0013] Preferably, the mass ratio of the glutaric acid to the sodium carboxymethyl cellulose is 2:1.

[0014] By adopting the above technical solution, during the stirring process, the pentenedioic acid polymer molecules are arranged on the gas-liquid interface to form a stable bubble film, with the hydrophilic ends facing the water and the hydrophobic ends facing the air. This arrangement reduces the possibility of bubble coalescence and maintains the stability of the bubbles. Therefore, pentenedioic acid promotes the uniform distribution and proper size of the air-entraining agent in the grouting slurry. Sodium carboxymethylcellulose can increase the bubble wall thickness and the viscosity of the liquid phase medium, which helps to enhance the stability of the bubbles, enabling the bubbles to stably exist inside the concrete during the parking and vibration processes of the grouting slurry without aggregating or escaping. The combination of the two further enhances the stability of the bubbles from different perspectives and reduces the direct rupture of the bubbles during the stirring process or the rupture due to aggregation and growth. Moreover, when the mass ratio of pentenedioic acid to sodium carboxymethylcellulose is 2:1, the two can achieve a better cooperation effect and the bubble stability is better.

[0015] Preferably, it further includes 0.4 - 0.8 parts by weight of nano-enhancing particles.

[0016] Preferably, the nano-enhancing particles are nano-silica.

[0017] By adopting the above technical solution, the nano-enhancing particles are introduced into the air-entraining agent liquid. The nano-enhancing particles can adsorb on the gas-liquid interface of the bubbles to generate a "particle skeleton" and form a dense "particle-reinforced film", which can effectively inhibit the aggregation and disproportionation between the bubbles. In addition, the adsorption energy of nano-silica in the bubble film is relatively large, and it is difficult to desorb when adsorbed on the gas-liquid interface of the bubbles.

[0018] In the second aspect, the present application provides a preparation method of a cement-based shield synchronous grouting material, adopting the following technical solution:

[0019] A preparation method of a cement-based shield synchronous grouting material includes the following steps:

[0020] S1: Add the air-entraining agent to water and stir evenly to obtain a mixed solution.

[0021] S2: Add cement, sand, fly ash, and bentonite to a mixer and stir evenly to obtain a dry material.

[0022] S3: Mix the mixed solution and the dry material and stir evenly to obtain the cement-based shield synchronous grouting material.

[0023] By adopting the above technical solution, the cement-based shield synchronous grouting material prepared through the above preparation steps has good fluidity, a large gas content, and a low cement content.

[0024] In summary, the present application has the following beneficial effects:

[0025] 1. This application uses sodium α-olefin sulfonate and coconut oil amide succinate as air-entraining agents. The two cooperate with each other to significantly reduce the slurry density, and can also significantly improve the fluidity and air content of the grouting slurry, reduce the time-dependent loss of consistency, with almost no change in compressive strength, and effectively reduce the grouting volume required for each ring, saving more than 0.35 m of slurry per ring. 3 , thus saving cement and reducing carbon emissions; moreover, due to the reduction of the grouting slurry density, the problem of segment floating is well solved.

[0026] 2. This application uses glutaric acid and sodium carboxymethyl cellulose. Glutaric acid promotes the uniform distribution and proper size of the air-entraining agent in the grouting slurry, and sodium carboxymethyl cellulose can increase the bubble wall thickness and the viscosity of the liquid medium, which helps to enhance the stability of the bubbles. The two are used in combination to reduce the direct rupture of bubbles during stirring or the rupture due to aggregation and enlargement.

[0027] 3. This application also introduces nano-enhanced particles into the grouting slurry. The nano-enhanced particles effectively inhibit the aggregation and disproportionation between bubbles, can reduce the rupture of bubbles caused by aggregation, and enhance the stability of bubbles.

[0028] Raw material sources

[0029] The cement is P·O42.5 ordinary Portland cement produced by Tangshan Hongtai Cement Co., Ltd.

[0030] The fly ash is Class II fly ash produced by Tianjin Guodian Jineng Thermal Power Co., Ltd.

[0031] The bentonite is sodium-based bentonite produced by Hongli Active Bentonite Factory in Fangzi District, Weifang City.

[0032] The sand is river sand with a fineness modulus of 1.4.

[0033] The sodium α-olefin sulfonate comes from Shandong Yousuo Chemical Industry, product number: S11202215.

[0034] The coconut oil amide succinate comes from Chongqing Ruiya Biotechnology Co., Ltd., product number: 61791-66-0.

[0035] The glutaric acid comes from Wuhan Xinweiye Chemical Co., Ltd., with a purity of 98%.

[0036] The sodium rosinate comes from Guangdong Wengjiang Chemical Reagent Co., Ltd., product number: PA30227.

[0037] The sodium alkylbenzene sulfonate comes from Hubei Kewode Chemical Industry Co., Ltd. Specific embodiments

[0038] The following further elaborates on this application in conjunction with examples.

[0039] Examples

[0040] Example 1

[0041] A preparation method of a cement-based shield synchronous grouting material, comprising the following steps:

[0042] S1: Add 0.5 kg of air-entraining agent (0.375 kg of α-olefin sulfonate and 0.125 kg of coconut oil amide succinate) to 330 kg of water, and stir at 500 r / min for 60 min to obtain a mixed solution;

[0043] S2: Add 170 kg of cement, 760 kg of sand, 240 kg of fly ash, and 50 kg of bentonite to a mixer, and stir evenly to obtain dry materials;

[0044] S3: Completely mix the obtained mixed solution and dry materials, and stir evenly to obtain a cement-based shield synchronous grouting material.

[0045] Example 2

[0046] A preparation method of a cement-based shield synchronous grouting material, comprising the following steps:

[0047] S1: Add 1 kg of air-entraining agent (0.75 kg of α-olefin sulfonate and 0.25 kg of coconut oil amide succinate) to 350 kg of water, and stir at 600 r / min for 50 min to obtain a mixed solution;

[0048] S2: Add 180 kg of cement, 770 kg of sand, 250 kg of fly ash, and 55 kg of bentonite to a mixer, and stir evenly to obtain dry materials;

[0049] S3: Completely mix the obtained mixed solution and dry materials, and stir evenly to obtain a cement-based shield synchronous grouting material.

[0050] Example 3

[0051] A preparation method of a cement-based shield synchronous grouting material, comprising the following steps:

[0052] S1: Add 2 kg of air-entraining agent (1.5 kg of α-olefin sulfonate and 0.5 kg of coconut oil amide succinate) to 370 kg of water, and stir at 650 r / min for 45 min to obtain a mixed solution;

[0053] S2: Add 190 kg of cement, 780 kg of sand, 260 kg of fly ash, and 60 kg of bentonite to a mixer, and stir evenly to obtain dry materials;

[0054] S3: Completely mix the obtained mixed solution and dry materials, and stir evenly to obtain a cement-based shield synchronous grouting material.

[0055] Example 4

[0056] The difference between Example 4 and Example 2 is that the addition amount of sodium α-olefin sulfonate is 0.8 kg, and the addition amount of coconut oil amide succinate is 0.2 kg, and the mass ratio of the two is 4:1. The remaining steps are the same as those in Example 2.

[0057] Example 5

[0058] The difference between Example 5 and Example 2 is that the addition amount of sodium α-olefin sulfonate is 0.7 kg, and the addition amount of coconut oil amide succinate is 0.3 kg, and the mass ratio of the two is about 5.7:1. The remaining steps are the same as those in Example 2.

[0059] Example 6

[0060] The difference between Example 6 and Example 2 is that the addition amount of sodium α-olefin sulfonate is 0.9 kg, and the addition amount of coconut oil amide succinate is 0.1 kg, and the mass ratio of the two is about 9:1. The remaining steps are the same as those in Example 2.

[0061] Example 7

[0062] The difference between Example 7 and Example 2 is that the addition amount of sodium α-olefin sulfonate is 0.7 kg, and the addition amount of coconut oil amide succinate is 0.3 kg, and the mass ratio of the two is about 2.3:1. The remaining steps are the same as those in Example 2.

[0063] Example 8

[0064] The difference between Example 8 and Example 4 is that 0.3 kg of additives are further added in step S1. The additives include 0.15 kg of pentene diacid and 0.15 kg of sodium carboxymethyl cellulose. The remaining steps are the same as those in Example 4.

[0065] Example 9

[0066] The difference between Example 9 and Example 4 is that 0.4 kg of additives are further added in step S1. The additives include 0.2 kg of pentene diacid and 0.2 kg of sodium carboxymethyl cellulose. The remaining steps are the same as those in Example 4.

[0067] Example 10

[0068] The difference between Example 10 and Example 4 is that 0.5 kg of additives are further added in step S1. The additives include 0.25 kg of pentene diacid and 0.25 kg of sodium carboxymethyl cellulose. The remaining steps are the same as those in Example 4.

[0069] Example 11

[0070] Example 11 is different from Example 9 in that the addition amount of glutaconic acid is 0.27 kg, and the addition amount of sodium carboxymethyl cellulose is 0.13 kg, and the mass ratio of the two is about 2:1, and the remaining steps are the same as those in Example 9.

[0071] Example 12

[0072] Example 12 is different from Example 9 in that the addition amount of glutaconic acid is 0.3 kg, and the addition amount of sodium carboxymethyl cellulose is 0.1 kg, and the mass ratio of the two is about 3:1, and the remaining steps are the same as those in Example 9.

[0073] Example 13

[0074] Example 13 is different from Example 11 in that 0.4 kg of nano-enhanced particles are further added in step S1, and the nano-enhanced particles are nano-silica, and the remaining steps are the same as those in Example 11.

[0075] Example 14

[0076] Example 14 is different from Example 11 in that 0.6 kg of nano-enhanced particles are further added in step S1, and the nano-enhanced particles are nano-silica, and the remaining steps are the same as those in Example 11.

[0077] Example 15

[0078] Example 15 is different from Example 11 in that 0.8 kg of nano-enhanced particles are further added in step S1, and the nano-enhanced particles are nano-silica, and the remaining steps are the same as those in Example 11.

[0079] Example 16

[0080] Example 16 is different from Example 15 in that the nano-enhanced particles are nano-titanium dioxide, and the remaining steps are the same as those in Example 15.

[0081] Comparative Example

[0082] Comparative Example 1

[0083] Comparative Example 1 is different from Example 1 in that no air-entraining agent is added, and the remaining steps are the same as those in Example 1.

[0084] Comparative Example 2

[0085] Comparative Example 2 is different from Example 1 in that all of the α-olefin sulfonate is replaced with an equal amount of coconut oil amide succinate, and the remaining steps are the same as those in Example 1.

[0086] Comparative Example 3

[0087] The difference between Comparative Example 3 and Example 1 is that all of the cocamidopropyl sulfosuccinate is replaced with an equal amount of sodium α-olefin sulfonate, and the remaining steps are the same as those in Example 1.

[0088] Comparative Example 4

[0089] The difference between Comparative Example 4 and Example 1 is that the sodium α-olefin sulfonate is replaced with an equal amount of sodium rosinate, and the remaining steps are the same as those in Example 1.

[0090] Comparative Example 5

[0091] The difference between Comparative Example 5 and Example 1 is that all of the cocamidopropyl sulfosuccinate is replaced with an equal amount of sodium rosinate, and the remaining steps are the same as those in Example 1.

[0092] Comparative Example 6

[0093] The difference between Comparative Example 6 and Example 1 is that the air-entraining agent is replaced with an equal amount of sodium alkylbenzene sulfonate, and the remaining steps are the same as those in Example 1.

[0094] Performance detection test

[0095] Detection method

[0096] Refer to the "Standard Test Method for Basic Properties of Building Mortars" JGJ / T 70—2009 to test the apparent density, air content, consistency, consistency loss after 2h, and 28d compressive strength after curing of the cement-based shield synchronous grouting materials in Examples 1-16 and Comparative Examples 1-6;

[0097] According to the statistical analysis of the grouting data at the construction site, taking a certain municipal drainage shield tunnel under construction in the coastal area as an example, the tunnel is composed of multiple rings of segment linings. The inner diameter of each segment is 3m, the outer diameter is 3.5m, and the ring width is 1.2m. Using the conventional synchronous grouting material, the final synchronous grouting pressure is set at 300 kPa, and the grouting volume per ring is calculated. The specific test results are shown in the following table:

[0098] Table 1 Performance test of the cement-based shield synchronous grouting materials in Examples 1-16 and Comparative Examples 1-6

[0099]

[0100]

[0101]

[0102] Combined with the data of Examples 1-3, Comparative Example 1 and Table 1, it can be seen that adding an air-entraining agent to the grouting slurry can reduce the slurry density from 1920 kg / m3 to 1710 kg / m3, and can also significantly improve the fluidity and air content of the grouting paste, reduce the time-dependent loss of consistency, with the compressive strength remaining almost unchanged, and effectively reduce the grouting volume required for each ring, saving 0.35 m of slurry per ring 3 , thereby saving cement and reducing carbon emissions.

[0103] Combined with the data of Example 2, Examples 4-7 and Table 1, it can be seen that when the mass ratio of α-olefin sulfonate and coconut oil amide succinate is (3-5.7):1, α-olefin sulfonate and coconut oil amide succinate can better play a cooperative role, generating richer and more stable bubbles, which can further improve the fluidity of the grouting slurry, reduce the time-dependent loss of consistency, reduce the density of the grouting slurry, and reduce the cement usage.

[0104] Combined with the data of Example 4, Examples 8-12 and Table 1, it can be seen that adding glutaric acid and sodium carboxymethyl cellulose in the S1 step can further enhance the stability of bubbles from different angles, avoiding the direct rupture or aggregation-induced rupture of bubbles during the mixing process of the paste, thereby further improving the fluidity of the grouting slurry, reducing the time-dependent loss of consistency, reducing the density of the grouting slurry, reducing the cement usage, and when the mass ratio of glutaric acid and sodium carboxymethyl cellulose is 2:1, the two can play a better cooperative effect, incorporated into the grouting paste, making the performance of the grouting paste slightly better.

[0105] Combined with the data of Example 11, Examples 13-16 and Table 1, it can be seen that adding nano-silica in the S1 step can further prevent the rupture of bubbles caused by bubble aggregation, thereby further improving the stability of bubbles and the overall performance of the grouting slurry, and from the data, the compressive performance of the solidified grouting paste is slightly improved, probably because some nano-particles fill the gaps between the cements, enhancing its compressive performance.

[0106] Judging from the data of Example 1, Comparative Examples 1-6 and Table 1, the present application uses α-olefin sulfonate and coconut oil amide succinate as air-entraining agents, and the two can cooperate with each other to form rich and stable bubbles, thereby improving the fluidity and air content of the mortar, reducing the density of the grouting slurry, and the compressive strength of the grouting slurry remains basically unchanged after curing.

[0107] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A cement-based synchronous grouting material for shield tunneling, characterized in that: It comprises the following raw materials in parts by weight: 170 - 190 parts of cement, 760 - 780 parts of sand, 240 - 260 parts of fly ash, 50 - 60 parts of bentonite, 330 - 370 parts of water, and 0.5 - 2 parts of air-entraining agent, wherein the air-entraining agent comprises sodium α-olefin sulfonate and coconut oil amide succinate sulfonate with a mass ratio of 4:

1.

2. The cement-based shield synchronous grouting material according to claim 1, characterized in that: It further comprises 0.3 - 0.5 parts by weight of an auxiliary agent, and the auxiliary agent comprises glutaric acid and sodium carboxymethyl cellulose.

3. The cement-based shield synchronous grouting material according to claim 2, characterized in that: The mass ratio of glutaric acid to sodium carboxymethyl cellulose is 2:

1.

4. The cement-based shield synchronous grouting material according to claim 2, characterized in that: It further comprises 0.4 - 0.8 parts by weight of nano-enhancing particles.

5. The cement-based shield synchronous grouting material according to claim 4, characterized in that: The nano-enhancing particles are nano-silica.

6. A preparation method of the cement-based synchronous grouting material for shield tunneling according to any one of claims 1-5, Its characteristics are as follows: It comprises the following steps: S1: Add the air-entraining agent into water and stir evenly to obtain a mixed solution; S2: Add cement, sand, fly ash, and bentonite into a mixer and stir evenly to obtain dry materials; S3: Mix the mixed solution and the dry materials and stir evenly to obtain a cement-based shield synchronous grouting material.

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