WO2024152438A1

WO2024152438A1 - Anti-seepage accelerator and preparation method therefor

Info

Publication number: WO2024152438A1
Application number: PCT/CN2023/083640
Authority: WO
Inventors: 赵明敏; 滕文生; 黄玉美; 米尔科·格鲁博; 刘昭洋; 李茜茜; 董树强; 田宇; 吕东伟; 韩晓东
Original assignee: 石家庄市长安育才建材有限公司; 四川砼道科技有限公司
Priority date: 2023-01-17
Filing date: 2023-03-24
Publication date: 2024-07-25
Also published as: CN115784664A; CN115784664B

Abstract

An anti-seepage accelerator and a preparation method therefor. Preparation raw materials comprise the following components in percentage by weight: 60%-70% of a coagulant, 6%-10% of a solubilizer, 2%-3% of an early-strength agent, 2%-3% of a rebound inhibitor, 1%-2% of a viscosity-reducing admixture, 1%-1.5% of a naphthalene-based water reducer, 0.5%-1% of a suspension agent and 0.01%-0.02% of a defoaming agent, with the balance being water, the rebound inhibitor comprising at least one of styrene-butadiene latex and a hydrophobic pore-blocking ingredient. The preparation method comprises: adding water and the suspension agent to a reaction vessel, and performing stirring shearing dispersion to obtain a pre-dispersed suspension agent slurry; mixing the pre-dispersed suspension agent slurry with water, adding the coagulant and the solubilizer, and stirring same while maintaining the temperature, so as to obtain a turbid liquid; mixing the turbid liquid with the early-strength agent; and then adding the viscosity-reducing admixture, the defoaming agent, the naphthalene-based water reducer and the rebound inhibitor. The synergistic effect of the raw materials of the anti-seepage accelerator can improve the anti-seepage performance of shotcrete.

Description

Anti-seepage quick-setting agent and preparation method thereof

This disclosure claims the priority of a patent application filed with the Chinese Patent Office on January 17, 2023, with application number CN202310061115.0 and patent name “Anti-seepage quick-setting agent and preparation method thereof”, the entire contents of which are incorporated by reference in this disclosure.

Technical Field

The present invention relates to the field of concrete building materials, and in particular to an anti-seepage type quick-setting agent. The present invention also relates to a method for preparing the anti-seepage type quick-setting agent.

Background technique

As an indispensable admixture for shotcrete, accelerators can promote the rapid coagulation and hardening of cement concrete and are widely used in tunnel construction of railway and highway projects. Liquid accelerators used for wet spraying of tunnels are divided into two categories: alkali accelerators and alkali-free accelerators. The alkali content of alkali (low alkali) liquid accelerators is generally greater than 1%. This type of liquid accelerator will more or less have an adverse effect on the mechanical properties and durability of concrete. Liquid alkali-free accelerators have been widely used in recent years because of their low alkali content, low corrosiveness, and do not affect the later strength and durability of concrete. However, the liquid alkali-free accelerators on the market currently generally have disadvantages such as high dosage, poor stability, low early strength, poor adaptability to cement, and high rebound rate.

The limitations of the geological environment increase the difficulty of tunnel construction and the risk of disasters, especially the influence of groundwater. Shotcrete is easily affected by groundwater. Even if the amount of water is small, it is easy to leak, which seriously affects the use function of the initial support shotcrete. In order to improve the impermeability of shotcrete, a common measure is to add silica powder, fly ash and other admixtures to shotcrete to improve its impermeability. Although it can improve the impermeability of shotcrete, its effect is very limited. At the same time, in complex situations such as water seepage and over-excavation in the surrounding rock working surface of the tunnel, the application effect of liquid alkali-free quick-setting agent is often not ideal. The rebound rate of shotcrete is as high as more than 20%, and the shotcrete has poor impermeability and low impermeability grade. The tunnel Water leakage in initial support shotcrete occurs frequently.

The application of liquid alkali-free quick-setting agent in tunnel shotcrete is greatly tested by the construction environment of water seepage, over-excavation, and ultra-fast support of soft surrounding rock. In particular, under the construction conditions of large-scale water seepage on the tunnel working face, higher requirements are put forward for liquid alkali-free quick-setting agent. Therefore, it is necessary to develop an anti-seepage type alkali-free liquid quick-setting agent for shotcrete, which can greatly reduce the rebound rate of shotcrete under complex conditions such as water seepage and over-excavation on the construction working face, and at the same time improve the mechanical properties and durability of shotcrete such as anti-seepage.

Summary of the invention

In view of this, the present disclosure proposes an anti-seepage quick-setting agent to improve the anti-seepage performance of shotcrete.

To achieve the above objectives, the technical solution of the present disclosure is implemented as follows:

The invention discloses an anti-seepage type quick-setting agent. The raw materials for preparing the anti-seepage type quick-setting agent include the following components by weight percentage: 60%-70% of a coagulant, 6%-10% of a solubilizer, 2%-3% of an early strength agent, 2%-3% of a rebound inhibitor, 1%-2% of a viscosity reducer, 1%-1.5% of a naphthalene-based water reducer, 0.5%-1% of a suspending agent, 0.01%-0.02% of a defoaming agent, and the rest is water; the rebound inhibitor includes at least one of styrene-butadiene latex and a hydrophobic compound pore plug.

Furthermore, the coagulant comprises components A and B in a mass ratio of (8.5-9):(1-1.5), component A comprises at least one of industrial grade aluminum sulfate 18hydrate and polyaluminum sulfate, and component B comprises at least one of basic aluminum carbonate, aluminum triformate, aluminum dihydrogen phosphate and amorphous aluminum hydroxide.

Furthermore, the solubilizing agent includes methyldiethanolamine and glycerol.

Furthermore, the mass ratio of methyldiethanolamine to glycerol is (4-5):1.

Furthermore, the early strength agent includes at least one of nano-hydrated calcium silicate, magnesium oxide and lithium hydroxide.

Furthermore, the viscosity reducer includes at least one of formic acid, phosphoric acid, oxalic acid and ethylenediaminetetraacetic acid.

Furthermore, the suspending agent includes at least one of lithium magnesium silicate, attapulgite and ultrafine sepiolite.

Furthermore, the suspending agent is prepared by modification using a silane coupling agent.

Furthermore, the naphthalene-based water reducer includes a naphthalene-based sulfonate condensate.

The impermeable quick-setting agent disclosed in the present invention has a high aluminum content, low viscosity and high stability, a stable period of more than 6 months, and a low dosage when mixed into concrete, which can improve the early strength of concrete, especially the 6h compressive strength and 1d compressive strength at an ultra-early age, without loss of later strength, and a high retention rate of 90d compressive strength. The shotcrete mixed with the impermeable quick-setting agent disclosed in the present invention has a low construction rebound rate and good impermeability under a water seepage environment, and is particularly suitable for tunnel construction projects where there is water seepage in the rock strata.

The present disclosure also proposes a method for preparing an anti-seepage type quick-setting agent, which comprises the following steps:

Add water and suspending agent into a reaction container, stir and shear disperse at a rotation speed of 2000-3000 rpm to obtain a pre-dispersed suspending agent slurry; mix the pre-dispersed suspending agent slurry with water, start stirring and heating, add a coagulant and a solubilizer, raise the temperature to 60-70° C., keep warm and stir for 1-2 hours to obtain a turbid liquid; mix the turbid liquid with an early strength agent, stir evenly, then add a viscosity reducer, a defoamer, a naphthalene-based water reducer, and a rebound inhibitor, stir evenly to obtain the anti-seepage type quick-setting agent.

Furthermore, before the pre-dispersed suspension slurry is obtained by stirring and shearing dispersion, a silane coupling agent is added into the reaction container.

Furthermore, the amount of the silane coupling agent used is 5% to 10% of the mass of the suspending agent.

Detailed ways

It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified. In addition, except for special instructions in this example, the terms and processes involved in this example are understood according to the general cognition and conventional methods in the prior art.

The invention discloses an anti-seepage type quick-setting agent. The raw materials for preparing the anti-seepage type quick-setting agent include the following components by weight percentage: 60%-70% of a coagulant, 6%-10% of a solubilizer, 2%-3% of an early strength agent, 2%-3% of a rebound inhibitor, 1%-2% of a viscosity reducer, 1%-1.5% of a naphthalene series water reducer, 0.5%-1% of a suspending agent, 0.01%-0.02% of a defoaming agent, and the rest is water; the rebound inhibitor includes at least one of styrene-butadiene latex and a hydrophobic compound pore plug.

Coagulants usually contain a certain amount of aluminum sulfate. Aluminum sulfate dissociates in water, and the sulfate ions produced by its hydrolysis react with the calcium ions produced by cement hydration to form fine secondary gypsum, which is more active than the original gypsum in cement, accelerates the reaction process with tricalcium aluminate in cement, and is more likely to generate needle-shaped ettringite crystals. In addition, aluminum sulfate can directly and quickly react with calcium hydroxide in the liquid phase to form ettringite. The volume of ettringite expands and interlaces to form a dense network structure, filling the pores and making the slurry dense, which is beneficial to the strength development and the rapid coagulation of cement concrete. On the other hand, due to the reduced concentration of calcium ions in the liquid phase, the dissolution of tricalcium aluminate is promoted. Aluminum ions can also accelerate the formation of C-S-H gel, shorten the induction period of tricalcium silicate, thereby accelerating the further hydration of tricalcium silicate, so that the cement can coagulate rapidly.

The coagulant disclosed in the present invention preferably comprises A and B components in a mass ratio of (8.5-9): (1-1.5), wherein the A component comprises at least one of industrial grade aluminum sulfate 18hydrate and polyaluminum sulfate, and the B component comprises at least one of basic aluminum carbonate, aluminum triformate, aluminum dihydrogen phosphate and amorphous aluminum hydroxide. Compared with the traditional single aluminum sulfate component (the molar ratio of aluminum to sulfate is 0.66), the two-component coagulant increases the aluminum content and reduces the sulfate content. The molar ratio of aluminum to sulfate in the coagulant is increased to 0.9-1.2, overcoming the shortcomings of the limited accelerating effect of the single aluminum sulfate component and the excessive sulfate that easily reduces the durability of concrete.

The solubilizer component can effectively improve the complexing ability of aluminum ions, greatly promote the full dissolution of aluminum ions in the liquid phase, so that the anti-seepage quick-setting agent with a higher aluminum content described in the present disclosure can meet the quick-setting requirements at a lower dosage of 5% to 6%. The solubilizer can preferably be an organic alcohol and an alcohol amine substance, such as methyldiethanolamine and glycerol in a mass ratio of (4-5): 1. Glycerol can not only serve as a co-solvent for aluminum sulfate, but also enhance the hardening properties of aluminum sulfate, thereby improving the early strength and post-wall strength of concrete and reducing the strength loss of concrete.

The early strength agent can reduce the nucleation barrier of cement hydration, provide the nucleation growth point of cement hydration products, accelerate the cement hydration process, effectively improve the ultra-early 6h to 24h compressive strength of mortar and concrete mixed with anti-seepage type quick-setting agent, and at the same time, the later strength guarantee rate is high. The early strength agent preferably adopts at least one of nano-hydrated calcium silicate, magnesium oxide and lithium hydroxide. The nano-hydrated calcium silicate can adopt the GK-3Z nano-microcrystalline material produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd., C-S-H hydrated calcium silicate suspension, the particle size of which is 20 to 50nm, which has a good effect on improving the early strength.

Viscosity reducers can inhibit the hydrolysis and precipitation of aluminum ions in anti-seepage quick-setting agents, while reducing the liquid's anti-seepage The viscosity of the type quick-setting agent is reduced to avoid the problem that the viscosity is too high after a long storage time or in a low temperature environment, and the injection equipment is not easy to extract. The viscosity reducer disclosed in the present invention preferably includes at least one of formic acid, phosphoric acid, oxalic acid and ethylenediaminetetraacetic acid.

The suspending agent is usually a silicate mineral, which presents a three-dimensional network structure after absorbing water, so it can adsorb aluminum in a suspended state, avoid crystallization of some aluminum phase materials in a suspended state after being stored at room temperature for a period of time or at low temperature, and improve the stability of the anti-seepage type quick-setting agent. The suspending agent preferably includes at least one of lithium magnesium silicate, attapulgite and ultrafine sepiolite. The suspending agent added in the present invention can be pre-dispersed by high-speed shear stirring to make the suspending agent particles dispersed evenly and improve the adsorption capacity. Compared with directly adding the suspending agent without pre-dispersion modification, the suspension efficiency of the supersaturated aluminum phase material in the anti-seepage type quick-setting agent of the present invention can be greatly improved, and under the synergistic effect of the above-mentioned viscosity reducer, the crystallization phenomenon of some aluminum phase materials in the suspended state can be avoided at room temperature or low temperature, and the stability is greatly improved.

The suspending agent can more preferably be modified by using a silane coupling agent to graft silaneoxy groups on the surface of the suspending agent. The modified suspending agent particles can generate steric hindrance and electrostatic repulsion, making the suspending agent more evenly dispersed, the three-dimensional network structure more stretched, and the complexing effect of aluminum ions better.

Polycarboxylate water reducer is usually added to the sprayed concrete during the preparation process to improve the working performance and fluidity of the concrete, but it is easy to rebound after being sprayed to the working surface. Therefore, the present disclosure also adds a naphthalene water reducer, which can be entangled with the comb-shaped structure molecules of the polycarboxylate water reducer contained in the sprayed concrete mixture itself, destroying the water-reducing effect of the polycarboxylate water reducer, so that the sprayed concrete mixture containing the polycarboxylate water reducer has a faster loss of fluidity and greatly improved cohesiveness during the spraying process, thereby reducing the rebound rate of the sprayed concrete. The naphthalene water reducer preferably includes a naphthalene sulfonate condensate, such as GK-3A produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd.

During the spraying process of shotcrete, certain bubbles are usually introduced, which reduces the strength of concrete. Therefore, a defoamer is added to the anti-seepage quick-setting agent disclosed in the present invention. The defoamer can be selected from at least one of the conventional Japanese Toho Chemical 910Z defoamer and Evonik surfynol DF-110 defoamer.

The rebound inhibitor uses at least one of styrene-butadiene latex and hydrophobic compound pore plugs. The rebound inhibitor can improve the bonding strength between the shotcrete and the construction work surface, and quickly solidify under construction conditions with water seepage, reducing the rebound rate of the shotcrete. It works synergistically with the defoamer component to jointly reduce the spraying The porosity of shotcrete can be reduced, and the anti-seepage performance of shotcrete can be greatly improved. The hydrophobic compound pore plug can be GK-KSW pore plug produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd., which can produce stearate with calcium and magnesium elements in concrete. Stearate can fill the gaps in concrete and block the capillaries. In addition, the hydrophobic compound pore plug has good hydrophobicity, reduces the water absorption rate of concrete, and prevents moisture from entering the concrete. Styrene-butadiene latex can be selected from at least one of 106 type and SD623 type.

The anti-seepage quick-setting agent disclosed in the present invention has a high aluminum content, low viscosity and stability, a stable period of more than 6 months, and a low dosage when mixed into concrete, which can improve the early strength of concrete, especially the 6h compressive strength and 1d compressive strength at an ultra-early age, without loss of later strength, and a high retention rate of 90d compressive strength. The shotcrete mixed with the anti-seepage quick-setting agent disclosed in the present invention has a low construction rebound rate and good anti-seepage performance under water seepage environment, and is particularly suitable for tunnel construction projects where there is water seepage in the rock strata.

The present disclosure also proposes a method for preparing an anti-seepage type quick-setting agent, which specifically comprises the following steps:

According to the above raw material ratio, add 1/2 of the total water and suspension agent in the reaction container, and stir at high speed for 30-60 minutes at a speed of 2000-3000rpm through a high-speed shear disperser to obtain a pre-dispersed viscous suspension slurry. Add the remaining 1/2 of water to the suspension slurry obtained in the above steps, turn on the stirring and heating switches, and under stirring, first add the coagulant B component and stir for 10-20 minutes; add the solubilizer and stir for 10-20 minutes; then add the coagulant A component, heat to 60-70°C, keep warm and stir for 1-2 hours, turn off the heating switch, and obtain a uniform turbid liquid. Then add the early strength agent and stir for 10-20 minutes; add the viscosity reducer and defoamer and stir for 20-30 minutes; add the water reducer and rebound inhibitor and stir for 30-60 minutes to obtain the anti-seepage quick-setting agent.

In order to achieve a better adsorption effect of the suspending agent, the preparation method disclosed herein can also adopt the following method when preparing the pre-dispersed viscous suspending agent slurry: add 1/2 of the total water volume and the suspending agent, and 5% to 10% of the mass of the silane coupling agent by weight of the suspending agent into the reaction container, and then use a high-speed shear disperser to stir at a speed of 2000-3000 rpm for 30-60 minutes to obtain the pre-dispersed viscous suspending agent slurry.

The specific implementation scheme of the present disclosure is described in detail below.

Example 1

The anti-seepage quick-setting agent of this embodiment includes the following raw materials by weight: 60% accelerator, 6% solubilizer, 2% early strength agent, 3% rebound inhibitor, 1% viscosity reducer, 1% water reducer, 0.5% suspending agent, 0.01% defoamer, The rest is water.

The above-mentioned coagulant is composed of components A and B in a mass ratio of 8.5:1.5, component A is industrial grade aluminum sulfate 18hydrate, component B is basic aluminum carbonate, and the molar ratio of aluminum to sulfate in the coagulant is 0.9-1.2; the solubilizer is composed of methyldiethanolamine and glycerol in a mass ratio of 4:1; the early strength agent is GK-3Z nano-microcrystalline material (nano C-S-H hydrated calcium silicate suspension with a particle size of 20-50nm, produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd.); the above-mentioned viscosity reducer is formic acid; the suspending agent is lithium magnesium silicate; the rebound inhibitor is 106 type styrene butadiene latex. The water reducer is a naphthalene sulfonate condensate, and Shijiazhuang Changan Yucai Building Materials Co., Ltd. produces GK-3A. The defoamer is Japan Toho Chemical 910Z defoamer.

The preparation method of the anti-seepage type quick-setting agent is as follows:

Preparation of modified suspension slurry: weigh the raw materials according to the ratio, add 1/2 water and suspension agent in the reaction container in sequence, and stir at high speed for 30 minutes at a speed of 2000 rpm using a high-speed shear disperser to obtain a pre-dispersed viscous suspension slurry.

Add the remaining 1/2 water to the prepared suspension slurry, turn on the stirring and heating switches, and first add the coagulant component B under stirring, and stir for 10 minutes; add the solubilizer and stir for 10 minutes; then add the coagulant component A, keep stirring at 60°C for 1 hour, turn off the heating switch, and obtain a uniform turbid liquid without solid particles.

Add early strength agent and stir for 10 minutes; add viscosity reducer and defoamer in sequence and stir for 20 minutes; add water reducer and rebound inhibitor in sequence and stir for 30 minutes to obtain anti-seepage quick-setting agent.

Embodiment 2:

The anti-seepage quick-setting agent of this embodiment comprises the following raw materials in parts by weight: 63% accelerator, 7.5% solubilizer, 2.5% early strength agent, 2.5% rebound inhibitor, 1.5% viscosity reducer, 1% water reducer, 0.6% suspending agent, 0.01% defoaming agent, and the rest is water.

The above-mentioned coagulant is composed of components A and B in a mass ratio of 8.5:1.5. Component A is industrial-grade polyaluminum sulfate, component B is aluminum triformate, and the molar ratio of aluminum to sulfate in the coagulant is 0.9-1.2; the solubilizer is methyldiethanolamine and glycerol in a mass ratio of 4.5:1; the early strength agent is lithium hydroxide; the above-mentioned viscosity reducer is ethylenediaminetetraacetic acid; the suspending agent is attapulgite; and the rebound inhibitor is SD623 type styrene-butadiene latex. The water reducer is a naphthalene sulfonate condensate, and Shijiazhuang Chang'an Yucai Building Materials Co., Ltd. produces GK-3A. Defoaming The defoaming agent is Evonik surfynol DF-110 defoaming agent.

According to the raw material ratio, 1/2 water, suspending agent and silane coupling agent are added to the reaction container in sequence. The amount of silane coupling agent is 10% of the mass of the suspending agent. Then, the mixture is passed through a high-speed shear disperser and stirred at a speed of 2500 rpm for 45 minutes to obtain a pre-dispersed viscous suspending agent slurry.

Add the remaining 1/2 water to the prepared suspension slurry, turn on the stirring and heating switches, and first add the coagulant component B under stirring, and stir for 10 minutes; add the solubilizer and stir for 10 minutes; then add the coagulant component A, keep stirring at 65°C for 1 hour, turn off the heating switch, and obtain a uniform turbid liquid without solid particles.

Add early strength agent and stir for 10 minutes; add viscosity reducer and defoamer in sequence and stir for 20 minutes; add water reducer and rebound inhibitor in sequence and stir for 45 minutes to obtain anti-seepage quick-setting agent.

Embodiment 3:

The anti-seepage quick-setting agent of this embodiment comprises the following raw materials in parts by weight: 67% accelerator, 8.5% solubilizer, 3% early strength agent, 2.5% rebound inhibitor, 1.5% viscosity reducer, 1.5% water reducer, 0.8% suspending agent, 0.02% defoaming agent, and the rest is water.

The above-mentioned coagulant is composed of components A and B in a mass ratio of 9:1, component A is industrial grade polyaluminum sulfate, component B is aluminum dihydrogen phosphate, and the molar ratio of aluminum to sulfate in the coagulant is 0.9-1.2; the solubilizer is composed of methyldiethanolamine and glycerol in a mass ratio of 4.5:1; the early strength agent is composed of lithium hydroxide and GK-3Z in a mass ratio of 1:1; the above-mentioned viscosity reducer is phosphoric acid; the suspending agent is ultrafine sepiolite; the rebound inhibitor is GK-KSW pore plug produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd. The water reducer is a naphthalene sulfonate condensate, and Shijiazhuang Changan Yucai Building Materials Co., Ltd. produces GK-3A. The defoamer is Evonik surfynol DF-110 defoamer.

According to the raw material ratio, 1/2 water, suspending agent and silane coupling agent are added to the reaction container in sequence. The amount of silane coupling agent is 5% of the mass of the suspending agent. Then, the mixture is passed through a high-speed shear disperser and stirred at a speed of 3000 rpm for 45 minutes to obtain a pre-dispersed viscous suspending agent slurry.

Add the remaining 1/2 water to the prepared suspension slurry, turn on the stirring and heating switches, and stir. In this state, first add the coagulant B component and stir for 15 minutes; add the solubilizer and stir for 15 minutes; then add the coagulant A component, keep warm and stir at 65°C for 1.5 hours, turn off the heating switch, and obtain a uniform turbid liquid without solid particles.

Add early strength agent and stir for 15 minutes; add viscosity reducer and defoamer in sequence and stir for 20 minutes; add water reducer and rebound inhibitor in sequence and stir for 60 minutes to obtain anti-seepage quick-setting agent.

Embodiment 4:

The anti-seepage quick-setting agent of this embodiment comprises the following raw materials in parts by weight: 70% accelerator, 9.5% solubilizer, 2.5% early strength agent, 3% rebound inhibitor, 2% viscosity reducer, 1.5% water reducer, 1% suspending agent, 0.02% defoamer, and the rest is water.

The above-mentioned coagulant is composed of components A and B in a mass ratio of 9:1, component A is industrial grade aluminum sulfate 18hydrate, component B is amorphous aluminum hydroxide, and the molar ratio of aluminum to sulfate in the coagulant is 0.9-1.2; the solubilizer is composed of methyldiethanolamine and glycerol in a mass ratio of 5:1; the early strength agent is lithium hydroxide; the above-mentioned viscosity reducer is oxalic acid; the suspending agent is attapulgite; the rebound inhibitor is GK-KSW pore plug produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd. The water reducer is a naphthalene sulfonate condensate, GK-3A produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd. The defoamer is Evonik surfynol DF-110 defoamer.

The preparation method of the anti-seepage type quick-setting agent of the present embodiment is as follows:

Weigh the raw materials according to the ratio, add 1/2 water and suspending agent into the reaction container in sequence, and stir at high speed for 60 minutes at a speed of 2500 rpm using a high-speed shear disperser to obtain a pre-dispersed viscous modified suspending agent slurry.

Add the remaining 1/2 water to the prepared modified suspension agent slurry, turn on the stirring and heating switches, and first add the coagulant component B under stirring, and stir for 20 minutes; add the solubilizer and stir for 20 minutes; then add the coagulant component A, keep stirring at 70°C for 2 hours, turn off the heating switch, and obtain a uniform turbid liquid without solid particles.

Add early strength agent and stir for 20 minutes; add viscosity reducer and defoamer in sequence and stir for 30 minutes; add water reducer and rebound inhibitor in sequence and stir for 60 minutes to obtain anti-seepage quick-setting agent.

The following is the experimental part (test group) of the present disclosure:

The recommended dosage of the anti-seepage quick-setting agent disclosed in the present invention in shotcrete is the total amount of cementitious materials. 4% to 7%. The general requirements of Q/CR 807-2020 for alkali-free accelerators are: alkali content ≤ 1.0%, chloride ion content ≤ 0.05%, and fluoride ion content ≤ 0.05%. After testing, the alkali content, chloride ion content and fluoride ion content of the anti-seepage accelerator prepared in Examples 1 to 4 all meet the above requirements. The performance requirements for the paste and mortar mixed with liquid alkali-free accelerator (dosage required 6% to 8%) are shown in Table 1. Since the performance index requirements of GB/T 35159-2017 "Accelerator for Shotcrete" are lower than those of Q/CR 807-2020, if the requirements of Q/CR 807-2020 are met, the requirements of GB/T 35159-2017 will definitely be met.

Table 1 Performance requirements of mortar and mortar mixed with liquid alkali-free accelerator (standard Q/CR807-2020)

Test Group 1

According to the test method specified in Q/CR 807-2020 "Liquid Alkali-free Accelerator for Tunnel Shotcrete", the anti-permeability type accelerators prepared in Examples 1 to 4 were tested for setting time, compressive strength and other indicators. The test cement is the benchmark cement P.I42.5.

The test examples without accelerating coagulant were used as blank groups.

The quick-setting agent of Comparative Example 1 is substantially the same as that of Example 1, except that no early strength agent component is added to Comparative Example 1.

The quick-setting agent of Comparative Example 2 is substantially the same as that of Example 1, except that no accelerator B component is added to Comparative Example 2.

The quick-setting agent of Comparative Example 3 is substantially the same as that of Example 1, except that the suspending agent of Comparative Example 3 is not modified to form a slurry, but is directly added to the metered water and stirred normally.

The quick-setting agent of Comparative Example 4 is substantially the same as that of Example 1, except that no rebound inhibitor component is added to Comparative Example 4.

The quick-setting agent of Comparative Example 5 is substantially the same as that of Example 2, except that the suspending agent of Comparative Example 5 is No silane coupling agent was added during the modification process to prepare the slurry.

The accelerating setting agent of comparative example 6 is prepared by the method of Example 1 of patent publication number CN 113603384 A.

The test results are shown in Table 2.

Table 2 Comparison of performance of various accelerators (benchmark cement)

As can be seen from the data in Table 2, the impermeability quick-setting agent disclosed in the present invention has excellent performance, with a dosage of 4% to 6%, which is lower than the dosage required by the standard Q/CR 807-2020 (6% to 8%) and the dosage required by GB/T 35159-2017 (6% to 9%), which is more conducive to saving project costs. In each embodiment, at a dosage of 4% to 6%, the benchmark cement is used for detection, and all performance indicators meet the requirements of the two standards of Q/CR 807-2020 and GB/T 35159-2017. The 6-hour compressive strength is greater than 3.5MPa, even as high as 4.8MPa, the 1-day compressive strength is greater than 18.0MPa, and the 6% dosage is even greater than 20MPa. The ultra-early age strength of 6 hours to 24 hours is high, which ensures construction safety and construction progress, and is particularly suitable for engineering projects with complex geological conditions such as weak surrounding rocks and requiring rapid support. The strength in the later stage does not shrink, and even increases. The 28-day compressive strength ratio is greater than 100%, and the 90-day compressive strength retention rate is greater than 110%.

Compared with Example 1, the quick-setting agent of Comparative Example 1 does not add the early strength agent, so the 6h compressive strength is lower than 2MPa, the 1d strength is lower than 15MPa, the 28d compressive strength ratio is less than 100%, and the 90d compressive strength ratio is less than 105%. The 90d compressive strength ratio index does not meet the requirements of Q/CR 807-2020 "Liquid Alkali-free Quick-setting Agent for Tunnel Shotcrete" standard; Compared with Example 1, the quick-setting agent of Comparative Example 2 does not add the accelerator B component, resulting in a significantly slower setting time at a dosage of 5%. , the final setting is greater than 12min, and the setting time does not meet the requirements of Q/CR 807-2020; the quick-setting agents of Comparative Example 3 (compared with Example 1, the suspension agent is not modified), Comparative Example 4 (compared with Example 1, no rebound inhibitor is added) and Comparative Example 5 (compared with Example 2, the suspension agent is modified without adding a silane coupling agent) are not much different from the anti-seepage quick-setting agent described in the present disclosure in terms of setting time and strength. Further rebound rate and stability tests are compared, see test group 2 and test group 3. The quick-setting agent of Comparative Example 6 has a slower setting time than the embodiments of the present disclosure at the same dosage, especially at 5% dosage, the initial setting time is greater than 5min, the final setting time is greater than 12min, and the setting time is unqualified.

Test Group 2

According to the test method for the stability of the accelerator in the Q/CR 807-2020 standard, the anti-seepage accelerator of each embodiment is placed at different temperatures and stored for a certain period of time. If the volume of the supernatant (or bottom sediment) in 100ml of liquid accelerator is ≤5mL, it is considered that the stability is qualified during the storage period, otherwise the stability is unqualified. At the same time, when stored for 3 months, the viscosity of the accelerator is tested, and the test results are shown in Table 3. Comparative Example The quick-setting agents of Comparative Examples 3 and 5 are the same as Comparative Examples 3 and 5 of Test Group 1.

Table 3 Stability and viscosity of accelerator (“√”: Stability qualified, “×”: Stability unqualified)

As can be seen from Table 3, the anti-seepage quick-setting agent disclosed in the present invention has good stability and antifreeze properties, and the shelf life (storage period) at room temperature of 20°C can reach more than 9 months, and the storage period at negative temperature of -18°C can reach more than 6 months (even 9 months). The anti-seepage quick-setting agent disclosed in the present invention is stored for 3 months, and the liquid viscosity at negative temperature of 18°C is still low (less than 700mPa.s), and the shelf life is long, which is suitable for engineering projects in various complex construction environments. The quick-setting agent of Comparative Example 3 (the contained suspending agent is not modified) has poor stability, a shelf life of less than 3 months at room temperature, a shelf life of less than 1 month at negative temperature, and a viscosity significantly increased after 3 months of storage at negative temperature, exceeding 1500mPa.S, and the risk of clogging the hose of the construction equipment is huge, which is difficult to apply in engineering. Compared with Example 2, the quick-setting agent of Comparative Example 5 does not add a silane coupling agent when the contained suspending agent is modified, and the negative temperature stability of the quick-setting agent of Comparative Example 5 for 9 months is unqualified, which is worse than Example 2.

Test Group 3

According to the method mentioned in Appendix G of JGJ/T372-2016 "Technical Specifications for the Application of Shotcrete", in a construction environment where water seepage exists in the surrounding rock, the shotcrete mixed with the anti-seepage type quick-setting agent disclosed in the present invention is tested. Concrete rebound rate; According to JGJ/T372-2016 "Technical Specification for Application of Shotcrete" and GB/T 50082-2019 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete", the anti-permeability performance (anti-permeability grade) of shotcrete mixed with the anti-permeability type quick-setting agent disclosed in the present invention was tested, and the test results are shown in Table 4. The cement used in the test is Esheng P.O42.5 cement, and the water reducer is GK-3000 polycarboxylic acid high-performance water reducer produced by Shijiazhuang Changan Yucai Building Materials Co., Ltd. The quick-setting agents of Comparative Examples 4 and 6 are the same as Comparative Examples 4 and 6 of Test Group 1.

Table 4 Rebound rate of shotcrete mixed with accelerating agent

It can be seen from Table 4 that under the same shotcrete mix ratio, the anti-seepage quick-setting agent disclosed in the present invention is used. At the dosage of 5% to 6%, the rebound rate of the shotcrete is relatively low (<5%), and the application effect is good. At the same time, the shotcrete mixed with the anti-seepage quick-setting agent disclosed in the present invention has excellent anti-seepage performance, and the anti-seepage grade reaches above P10. Compared with Example 1, the liquid alkali-free quick-setting agent of Comparative Example 4 does not contain a rebound inhibitor component, resulting in that even if the dosage is higher than that of Example 1, the rebound rate of the shotcrete is still much higher than that of Example 1, and the rebound rate exceeds 15%. Moreover, the shotcrete mixed with the quick-setting agent of Comparative Example 4 has a low anti-seepage grade of only P6, which does not meet the requirement that the anti-seepage grade of shotcrete in water-bearing rock formations should not be lower than P8 as stipulated in JGJ/T372-2016 "Technical Code for Application of Shotcrete". The liquid quick-setting agent of Comparative Example 6 has a higher rebound rate than the anti-seepage type quick-setting agent disclosed in the present invention, which is greater than 5%, and a poor anti-seepage performance, with an anti-seepage grade lower than P10 and only reaching P8.

In summary, the anti-seepage quick-setting agent disclosed in the present invention has good comprehensive performance. At a low dosage of 4% to 6%, it can meet the performance index requirements of standards Q/CR 807-2020 "Liquid alkali-free quick-setting agent for tunnel shotcrete" and GB/T35159-2017 "Accelerator for shotcrete", and the 6h compressive strength of the mortar is ≥3.5MPa, 1d compressive strength>18MPa, 90d compressive strength retention rate>110%, with high compressive strength of mortar at ultra-early age of 6h to 24h, high strength retention rate in the later stage, good stability and frost resistance. At the same time, using the anti-seepage quick-setting agent disclosed in the present invention, the shotcrete has low rebound rate and excellent anti-seepage performance. The anti-seepage quick-setting agent disclosed in the present invention has a simple preparation process, is fluorine-free, alkali-free, and chlorine-free, is green and environmentally friendly, and is very suitable for promotion and application, especially suitable for complex construction environments such as water seepage, severe cold, and weak surrounding rocks, and engineering projects that require rapid support.

The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

Claims

An anti-seepage type quick-setting agent, characterized in that the raw materials for preparing the anti-seepage type quick-setting agent include the following components by weight percentage: 60%-70% of a coagulant, 6%-10% of a solubilizer, 2%-3% of an early strength agent, 2%-3% of a rebound inhibitor, 1%-2% of a viscosity reducer, 1%-1.5% of a naphthalene-based water reducer, 0.5%-1% of a suspending agent, 0.01%-0.02% of a defoaming agent, and the rest is water; the rebound inhibitor includes at least one of styrene-butadiene latex and a hydrophobic compound pore plug.
The anti-seepage quick-setting agent according to claim 1 is characterized in that the accelerator comprises components A and B in a mass ratio of (8.5-9):(1-1.5), component A comprises at least one of industrial grade aluminum sulfate 18hydrate and polyaluminum sulfate, and component B comprises at least one of basic aluminum carbonate, aluminum triformate, aluminum dihydrogen phosphate and amorphous aluminum hydroxide.
The anti-seepage quick-setting agent according to claim 1, characterized in that the solubilizing agent comprises methyldiethanolamine and glycerol.
The anti-seepage quick-setting agent according to claim 3 is characterized in that the mass ratio of methyldiethanolamine to glycerol is (4-5):1.
The anti-seepage quick-setting agent according to claim 1 is characterized in that the early strength agent includes at least one of nano-hydrated calcium silicate, magnesium oxide and lithium hydroxide.
The anti-seepage quick-setting agent according to claim 1 is characterized in that the viscosity reducer includes at least one of formic acid, phosphoric acid, oxalic acid and ethylenediaminetetraacetic acid.
The anti-seepage quick-setting agent according to claim 1 is characterized in that the suspending agent includes at least one of lithium magnesium silicate, attapulgite and ultrafine sepiolite.
The anti-seepage quick-setting agent according to claim 1 is characterized in that the suspending agent is prepared by modification with a silane coupling agent.
The anti-seepage quick-setting agent according to any one of claims 1 to 8, characterized in that the naphthalene-based water reducer comprises a naphthalene-based sulfonate condensate.
A method for preparing an anti-seepage quick-setting agent, characterized in that the method comprises the following steps:

Add water and suspending agent into the reaction container, stir and shear and disperse at a speed of 2000-3000 rpm to obtain a pre-dispersed suspending agent slurry;

The pre-dispersed suspension slurry is mixed with water, stirring and heating are started, a coagulant and a solubilizer are added, the temperature is raised to 60-70° C., and the mixture is stirred for 1-2 hours to obtain a turbid liquid;

The turbid liquid is mixed with an early strength agent, stirred evenly, and then a viscosity reducer, a defoamer, a naphthalene-based water reducer, and a rebound inhibitor are added, stirred evenly, to obtain the anti-seepage type quick-setting agent.
The method for preparing an anti-seepage quick-setting agent according to claim 10 is characterized in that a silane coupling agent is also added to the reaction container before the pre-dispersed suspension slurry is obtained by stirring and shearing dispersion.
The method for preparing an anti-seepage type quick-setting agent according to claim 11 is characterized in that the amount of the silane coupling agent used is 5% to 10% of the mass of the suspending agent.