Preparation process of low-temperature fluidized curing agent and cured earth building material thereof

Abstract

The application relates to the technical field of building material preparation, and particularly discloses a preparation process of a low-temperature flow-state curing agent and a cured soil building material, which comprises the following steps: (1) adding modified starch into water, stirring until uniform, and then removing oxygen; then adding maleic anhydride and persulfate for heating reaction; after the reaction is completed, adding ethanol, separating out precipitates, and drying to obtain CMSS-g-MA; (2) adding glycine betaine into water, stirring until uniform, then adding CMSS-g-MA for heating reaction; after the reaction is completed, performing spray drying on the obtained reaction liquid to obtain modified betaine powder; and (3) taking sulphoaluminate cement, ordinary Portland cement, polycarboxylate superplasticizer, silane coupling agent, the modified betaine powder and hydroxyethyl cellulose as raw materials, mixing the raw materials until uniform, and then obtaining a low-temperature flow-state curing agent. The application can better avoid the freezing of a cured soil slurry in a low-temperature environment, maintain the stability of the internal structure of the cured soil, and provide guarantee for low-temperature construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building material preparation, and particularly relates to a preparation process of a low-temperature flow-state curing agent and a cured soil building material. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission or a recognition that the information forms part of the prior art already known to a person of ordinary skill in the art.

[0003] The ordinary curing agent has a ratio contradiction between flowability and water requirement: when the mixing water content is insufficient, the particles are easily aggregated and lubricated, which leads to substandard flowability and is difficult to meet the self-leveling construction requirements; if the mixing water content is increased to improve the flowability, segregation and bleeding will be caused, and the risk of freezing in a low-temperature environment will be further intensified. The ordinary Portland cement-based curing agent has a slow hydration reaction below 5℃, a slow strength growth, and an internal freezing when the water content is high, which directly damages the integrity of the curing structure.

[0004] Most of the existing low-temperature curing agents are mainly high-activity cementing materials, such as high-grade cement + active slag, which has a large hydration water requirement, so that the flowability optimization range is further compressed, and it is difficult to adapt to the needs of various high-flow construction scenes. The traditional "antifreeze component + early strength component" compounding scheme also has shortcomings: the antifreeze component (such as sodium chloride) is easy to have a flocculation reaction with the water reducing agent, which reduces the dispersion effect of the antifreeze component. The addition of the early strength component (such as sodium sulfate) also damages the flowability of the slurry to different degrees. In addition, the dosage of such admixtures needs to be accurately controlled, otherwise it is easy to cause abnormal setting and late strength reduction, and its application is difficult. SUMMARY

[0005] The present application provides a preparation process of a low-temperature flow-state curing agent and a cured soil building material, which can better avoid the freezing of the cured soil slurry in a low-temperature environment and maintain the stability of the internal structure of the cured soil, thereby providing protection for low-temperature construction. Specifically, the technical scheme of the present application is as follows.

[0006] Firstly, the present application provides a preparation process of a low-temperature flow-state curing agent, which comprises the following steps:

[0007] (1) starch is added to hot water and stirred to gelatinize, then alkali solution and 2-bromo sodium acetate are added and heated to react. After completion, the reaction system is adjusted to neutral, then ethanol is added for precipitation, the precipitate is separated and ground to obtain modified starch.

[0008] (2) Add the modified starch into water, stir until uniform, and then remove oxygen. Then add maleic anhydride (MA) and persulfate for heating reaction. After completion, add ethanol for precipitation, grind the precipitate after separation, and obtain CMSS-g-MA powder.

[0009] (3) Add glycine betaine (GB) into water, stir until uniform, and then add the CMSS-g-MA powder for heating reaction. After completion, spray dry the obtained reaction solution to obtain modified betaine powder (GB / CMSS-g-MA).

[0010] (4) Take sulphoaluminate cement, ordinary portland cement, polycarboxylate superplasticizer, water-based epoxy resin emulsion, silane coupling agent, the modified betaine powder, and hydroxyethyl cellulose as raw materials, mix them uniformly to obtain the low-temperature flowable curing agent.

[0011] Further, in step (1), the mass ratio of the starch to hot water is 1:5-5.8. Optionally, the temperature of the hot water is 80-85℃. By gelatinizing the starch, the active hydroxyl group (-OH) is exposed, and the reaction uniformity is improved.

[0012] Further, in step (1), the mass ratio of the sodium 2-bromoacetate, starch, and lye is 0.5-0.6:2-2.4:0.4-0.44. Optionally, the mass fraction of the lye is 10-12%.

[0013] Further, in step (1), the lye includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, lithium hydroxide, etc.

[0014] Further, in step (1), the temperature of the heating reaction is 60-65℃, and the time is 1-2h. The active hydroxyl group reacts with the -COO - provided by the sodium 2-bromoacetate under alkaline conditions, thereby introducing a carboxymethyl group -O-CH2-COONa on the starch to form the modified starch.

[0015] Further, in step (1), at least one of dilute hydrochloric acid and dilute HBr is used to adjust the reaction system to neutral to prevent hydrolysis of the carboxymethyl group.

[0016] Further, in step (1), the mass ratio of the reaction system to ethanol is 1:1.5-2.

[0017] Further, in step (1), the fineness of the modified starch is 75-100 mesh.

[0018] Further, in step (2), the mass ratio of the modified starch to water is 1:8-9.

[0019] Further, in step (2), the mass ratio of the modified starch, maleic anhydride (MA) and persulfate is 10-12:1.8-2.2:0.1-0.2. Optionally, the persulfate includes at least one of ammonium persulfate, potassium persulfate, etc.

[0020] Further, in step (2), the heating reaction is performed at a temperature of 60-65°C for 1-2h. The persulfate is decomposed to form sulfate free radicals ∙OSO3 - under the heating condition, which can abstract the α-H of the hydroxyl group on the modified starch (CMS) to form an activated site -CH∙-OH. The C=C of the maleic anhydride (MA) is combined with the activated site to form a stable CMSS-g-MA.

[0021] Further, in step (2), the fineness of the CMSS-g-MA powder is 75-100 mesh.

[0022] Further, in step (3), the mass ratio of the glycine betaine, water and CMSS-g-MA powder is 1:6:2-3.

[0023] Further, in step (3), the heating reaction is performed at a temperature of 60-65°C for 1-2h. The -N + of the glycine betaine is combined with the carboxyl group -COO - provided by the carboxymethyl group -O-CH2-COONa in the CMSS-g-MA through the coulomb force, and simultaneously -COO - is associated with -OH on the modified starch through the hydrogen bond, and the residual C=C in the maleic anhydride (MA) is reacted with -NH2 of the glycine betaine to form a C-N covalent bond. The modified betaine powder (GB / CMSS-g-MA) with the composite network structure is formed through the electrostatic attraction-hydrogen bond-covalent bond mode.

[0024] Further, in step (4), the proportions of the components in the raw materials are as follows: 3-4 parts by weight of sulphoaluminate cement, 3-5 parts by weight of ordinary portland cement, 0.05-0.06 parts by weight of polycarboxylate superplasticizer, 0.4-0.5 parts by weight of water-based epoxy resin emulsion, 0.07-0.1 parts by weight of silane coupling agent, 0.5-0.7 parts by weight of modified betaine powder, and 0.01-0.025 parts by weight of hydroxyethyl cellulose.

[0025] Further, in step (4), the silane coupling agent includes at least one of KH-550, KH-560, KH-570, etc.

[0026] Further, in step (4), the solid content of the water-based epoxy resin emulsion is 40-43 wt.%.

[0027] Secondly, the present invention provides a solidified soil building material, comprising the following components: 70-78 parts by weight of soil, 12-15 parts by weight of the low-temperature fluidized solidifying agent, and 27-33 parts by weight of mixing water.

[0028] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0029] (1) The modified betaine powder (GB / CMSS-g-MA) in the curing agent of the present invention is a composite network structure formed by electrostatic attraction-hydrogen bond-covalent bond. It can efficiently wrap and lock the mixing water, avoid the accumulation and migration of water in the solidified soil, effectively reduce the content of free water that can freeze at low temperature, and effectively reduce the freezing point of the mixing water in the fluidized solidified soil. This better prevents the fluidized solidified soil from freezing in low temperature environment, and facilitates the better maintenance of the stability of its internal structure, thus providing a guarantee for low temperature construction.

[0030] (2) The modified betaine prepared in this invention is an amphoteric-polymer composite system. Its intramolecular electrical balance can prevent electrostatic bonding with the polycarboxylate superplasticizer in the curing agent, thus avoiding problems such as particle agglomeration, substandard slurry fluidity, or segregation and bleeding caused by the failure of the polycarboxylate superplasticizer. This is because the modified betaine molecule prepared in this invention contains approximately equal amounts of positively charged groups (-N). + (CH3)3) and negatively charged groups (-COO) - The two components form a stable electrical balance through intramolecular Coulomb forces, resulting in a state of zero net charge for the molecules. This prevents electrostatic attraction between the modified betaine and the polycarboxylate superplasticizer (whose main chain contains a large number of negatively charged carboxyl / sulfonic acid groups). This not only avoids the superplasticizer losing its dispersing function due to electrostatic neutralization but also enhances the dispersion of the solidified soil particles through the synergistic effect of the modified betaine and the polycarboxylate superplasticizer, achieving a superimposed adsorption layer. This is because the polycarboxylate superplasticizer first adsorbs onto the surface of the solidified soil particles, where its negatively charged main chain is fixed and its long side chains form a thin barrier to prevent particle agglomeration. The modified betaine then fills the vacancies on the particle surface not covered by the superplasticizer, using a three-dimensional network to expand the thin barrier formed by the polycarboxylate superplasticizer into a thick and stable protective layer. It also increases the negative charge on the particle surface, making the repulsive force between particles stronger. This superimposed effect results in more uniform dispersion of the solidified soil particles, maintaining self-leveling even with low mixing water content. Meanwhile, the water-based epoxy resin emulsion in the curing agent of the present invention can form a uniform lubricating film on the surface of soil and cementitious particles, significantly reducing the friction between particles, so that even when the mixing water content is low, the cured soil can still maintain smooth sliding.

[0031] (3) The modified betaine prepared by this invention can utilize its -N +(CH3)3 adsorbed on the surface of the sulphoaluminate cement particles polarizes the Ca 2+ , Al 3+ , reduces the ion-mineral lattice binding energy, accelerates cement hydration, makes the required ions for reaction quickly reach the threshold, and avoids the problem of slow reaction due to low temperature leading to reduced solubility. Meanwhile, the silane coupling agent in the curing agent hydrolyzes to generate SiOH under the alkaline environment provided by the OH - group on the soil, sulphoaluminate cement and ordinary Portland cement, forms stable Si-O covalent bonds, eliminates the interface gap between the organic and inorganic phases, reduces the weak interface area, strengthens the multi-phase interface bonding, avoids cracking due to weak interface bonding in a low temperature environment, and improves the mechanical strength and structural integrity of the cured soil. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of the present description, illustrate the present application and, together with the written description, serve to explain the principles of the present application. In the drawings:

[0033] Figure 1 is a GB / CMSS-g-MA powder sample graph for the following Example 1.

[0034] Figure 2 is a 12h hydration product XRD test graph of the cured soil building material for the following Example 1.

[0035] Figure 3 is a 28d compressive strength test graph for the following Example 1.

[0036] Figure 4 is a GB / CMSS-g-MA powder sample graph for the following Example 2.

[0037] Figure 5 is a 12h hydration product XRD test graph of the cured soil building material for the following Example 2.

[0038] Figure 6 is a 28d compressive strength test graph for the following Example 2.

[0039] Figure 7 is a GB / CMSS-g-MA powder sample graph for the following Example 3.

[0040] Figure 8 is a 12h hydration product XRD test graph of the cured soil building material for the following Example 3.

[0041] Figure 9 is a 28d compressive strength test graph for the following Example 3.

[0042] Figure 10 XRD test pattern of 12h hydration product of cured soil construction material for Example 4 below.

[0043] Figure 11 Compressive strength test pattern of 28d for Example 4 below.

[0044] Figure 12 GB / CMSS-g-MA powder sample pattern for Example 5 below.

[0045] Figure 13 XRD test pattern of 12h hydration product of cured soil construction material for Example 5 below.

[0046] Figure 14 Compressive strength test pattern of 28d for Example 5 below.

[0047] Figure 15 GB / CMSS-g powder sample pattern for Example 6 below.

[0048] Figure 16 XRD test pattern of 12h hydration product of cured soil construction material for Example 6 below.

[0049] Figure 17 Compressive strength test pattern of 28d for Example 6 below.

[0050] Figure 18 XRD test pattern of 12h hydration product of cured soil construction material for Example 7 below.

[0051] Figure 19 Compressive strength test pattern of 28d for Example 7 below. DETAILED DESCRIPTION

[0052] The application will be further described with reference to the following examples. It should be appreciated that these examples are intended to be illustrative only and are not intended to limit the scope of the present application. Unless otherwise indicated, the experimental procedures in the following examples were carried out in accordance with conventional procedures or as recommended by the manufacturer.

[0053] Unless otherwise defined, all technical and scientific terms used in the application have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or materials used in the present application can be purchased through conventional routes. Unless otherwise specified, the reagents or materials used in the present application are used in accordance with conventional methods or as recommended by the manufacturer.

[0054] Furthermore, any method and material similar or equivalent to those described herein can be used in the present application. The technical solutions of the present application will be further described with reference to the accompanying drawings and specific examples.

[0055] Embodiment 1: A preparation process of a solidified soil building material, comprising the following steps:

[0056] (1) The starch is mixed with hot water at 80℃ at a mass ratio of 1:5, and then stirred and gelatinized. Then, lye (10% sodium hydroxide solution by mass) and 2-bromo sodium acetate are added, and the mixture is heated to 60℃ and reacted for 1.5 hours. The mass ratio of the 2-bromo sodium acetate, starch, and lye is 0.52:2.2:0.43. After completion, the reaction system is adjusted to neutral with dilute hydrochloric acid, and then anhydrous ethanol is added for precipitation. The mass ratio of the reaction system and anhydrous ethanol is 1:1.7. After completion, the precipitate is filtered, ground, and then sieved through a 100-mesh sieve to obtain modified starch.

[0057] (2) The modified starch is mixed with water at a mass ratio of 1:8, stirred uniformly, and then deoxygenated by passing N2. Then, maleic anhydride and ammonium persulfate are added, and the mixture is heated to 60℃ and reacted for 2 hours. The mass ratio of the modified starch, maleic anhydride, and ammonium persulfate is 10:2:0.15. After completion, the obtained reaction system is precipitated with anhydrous ethanol whose mass is twice that of the reaction system, and then the precipitate is filtered, ground, and sieved through a 100-mesh sieve to obtain CMSS-g-MA powder.

[0058] (3) Glycine betaine is mixed with water, stirred uniformly, and then the CMSS-g-MA powder is added. The mixture is heated to 60℃ and reacted for 2 hours. The mass ratio of the glycine betaine, water, and CMSS-g-MA powder is 1:6:2.5. After completion, the obtained reaction liquid is spray-dried to obtain GB / CMSS-g-MA powder, as shown in Figure 1 .

[0059] (4) The following components are taken in the following proportions: sulphoaluminate cement 3.2 parts by weight, 42.5 ordinary portland cement 4 parts by weight, polycarboxylic acid water reducer 0.05 parts by weight, water-based epoxy resin emulsion with a solid content of 40wt.% 0.45 parts by weight, silane coupling agent (KH-550) 0.08 parts by weight, GB / CMSS-g-MA powder of the present embodiment 0.6 parts by weight, and hydroxyethyl cellulose 0.02 parts by weight. The above components are mixed uniformly to obtain a low-temperature flowable solidifying agent.

[0060] (5) The following components are taken in the following proportions: soil material 73 parts by weight, low-temperature flowable solidifying agent of the present embodiment 14 parts by weight, and mixing water 30 parts by weight. The above raw materials are mixed uniformly to obtain a solidified soil building material.

[0061] Performance test: the performance index test results of the cured soil building material prepared in this embodiment are shown in the following table. At the same time, the fluidity is tested according to the Standard Test Method for Controlled Low-Strength Material (CLSM) Slump (ASTM D6103), the setting time (initial setting / final setting) is tested according to the Standard Test Method for Water Content, Fineness of Retarder, and Soundness of Hydraulic Cement Mortar (GB / T 1346-2024), and the 12h hydration product XRD is tested by using a D8 Advance X-ray diffractometer (the results are shown in Figure 2 ). The compressive strength is tested according to the Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (ASTM C 109) (as shown in Figure 3 ). The compressive strength test specimen is obtained after being cured at 0℃ for 3d, demolded, transferred to a curing box for standard curing for 28d. It can be seen from the XRD test results that the cured soil building material of this embodiment still maintains good hydration degree after low-temperature curing, and the hydration is sufficient, indicating that the anti-freezing performance is good:

[0062]

[0063] Embodiment 2: A preparation process of a cured soil building material, comprising the following steps:

[0064] (1) The starch is mixed with hot water at 80℃ at a mass ratio of 1:5.5, then the starch is pasted by stirring, then the alkali solution (10% sodium hydroxide solution by mass fraction) and 2-bromoacetic acid sodium are added, and the reaction system is heated to 65℃ and reacted for 1 hour. The mass ratio of the 2-bromoacetic acid sodium, the starch and the alkali solution is 0.5:2:0.4. After completion, the reaction system is adjusted to neutral by using dilute hydrochloric acid, then anhydrous ethanol is added for precipitation, and the mass ratio of the reaction system and the anhydrous ethanol is 1:1.5. After completion, the precipitate is filtered out, ground, then sieved through an 80-mesh sieve, and the modified starch is obtained.

[0065] (2) The modified starch is mixed with water at a mass ratio of 1:9, stirred uniformly, and then deoxygenated by introducing N2. Then maleic anhydride and ammonium persulfate are added, and the reaction system is heated to 65℃ and reacted for 1 hour. The mass ratio of the modified starch, the maleic anhydride and the ammonium persulfate is 11:1.8:0.1. After completion, the obtained reaction system is precipitated by adding anhydrous ethanol with twice the mass of the reaction system, then the precipitate is filtered out, ground, and sieved through an 80-mesh sieve, and the CMSS-g-MA powder is obtained.

[0066] (3) The glycine betaine is mixed with water, stirred uniformly, then the CMSS-g-MA powder is added, and the reaction system is heated to 65℃ and reacted for 1 hour. The mass ratio of the glycine betaine, the water and the CMSS-g-MA powder is 1:6:2. After completion, the obtained reaction liquid is spray dried, and the GB / CMSS-g-MA powder is obtained. Figure 4as shown.

[0067] (4) Take the following proportions of components: 3 parts by weight of sulphoaluminate cement, 3 parts by weight of 42.5 ordinary Portland cement, 0.05 parts by weight of polycarboxylate superplasticizer, 0.4 parts by weight of water-based epoxy resin emulsion with a solid content of 43 wt.%, 0.07 parts by weight of silane coupling agent (KH-560), 0.5 parts by weight of GB / CMSS-g-MA powder of the present embodiment, and 0.01 parts by weight of hydroxyethyl cellulose. Mix the above components uniformly to obtain a low-temperature fluid curing agent.

[0068] (5) Take the following proportions of components: 78 parts by weight of soil, 15 parts by weight of the low-temperature fluid curing agent of the present embodiment, and 32 parts by weight of mixing water. Mix the above raw materials uniformly to obtain a cured soil building material.

[0069] Performance test: The performance indicators of the cured soil building material prepared in the present embodiment were tested in the same manner as in Embodiment 1, wherein the XRD test results of the 12h hydration product are shown in Figure 5 , the compressive strength test results are shown in Figure 6 , and the results are shown in the following table. Meanwhile, from the XRD test results, it can be seen that the cured soil building material of the present embodiment still maintains good hydration degree after low-temperature curing, and the hydration is relatively sufficient, indicating that it has good frost resistance:

[0070]

[0071] Embodiment 3: A preparation process of a cured soil building material, comprising the following steps:

[0072] (1) Mix starch with hot water at 85℃ at a mass ratio of 1:5.8, then stir and gelatinize, then add alkali solution (12% mass fraction of potassium hydroxide solution), 2-bromo sodium acetate, and heat to 60℃ for 2 hours, the mass ratio of 2-bromo sodium acetate, starch, and alkali solution is 0.6:2.4:0.44. After completion, adjust the reaction system to neutral with dilute hydrochloric acid, then add anhydrous ethanol for precipitation, the mass ratio of the reaction system and anhydrous ethanol is 1:2. After completion, filter out the precipitate and grind, then pass through a 75 mesh sieve to obtain modified starch.

[0073] (2) Mix the modified starch with water at a mass ratio of 1:8.5, stir uniformly, then deoxygenate by passing N2. Then add maleic anhydride and potassium persulfate and heat to 60℃ for 2 hours, the mass ratio of modified starch, maleic anhydride, and potassium persulfate is 12:2.2:0.2. After completion, add anhydrous ethanol with twice the mass of the obtained reaction system for precipitation, then filter out the precipitate and grind, pass through a 75 mesh sieve to obtain CMSS-g-MA powder.

[0074] (3) Glycine betaine and water were mixed and stirred until uniform, then the CMSS-g-MA powder was added and heated to 60°C for 1.5 hours, the mass ratio of the glycine betaine, water, and CMSS-g-MA powder being 1:6:3. After completion, the reaction solution was spray dried to obtain the GB / CMSS-g-MA powder, as shown in Figure 7 .

[0075] (4) The following components were taken in the following proportions: sulphoaluminate cement 4 parts by weight, 42.5 ordinary Portland cement 5 parts by weight, polycarboxylate superplasticizer 0.06 parts by weight, water-based epoxy resin emulsion with a solid content of 40 wt.% 0.5 parts by weight, silane coupling agent (KH-570) 0.1 parts by weight, GB / CMSS-g-MA powder of the present embodiment 0.7 parts by weight, hydroxyethyl cellulose 0.025 parts by weight. The above components were mixed until uniform to obtain a low-temperature flowable curing agent.

[0076] (5) The following components were taken in the following proportions: soil 70 parts by weight, low-temperature flowable curing agent of the present embodiment 12 parts by weight, mixing water 28 parts by weight. The above raw materials were mixed until uniform to obtain a cured-soil building material.

[0077] Performance testing: the various performance indicators of the cured-soil building material prepared in the present embodiment were tested in the same manner as in the above Example 1, wherein the 12h hydration product XRD test results are shown in Figure 8 , the compressive strength test results are shown in Figure 9 , and the results are shown in the following table. At the same time, from the XRD test results, it can be seen that the cured-soil building material of the present embodiment still maintains good hydration degree after low-temperature curing, and the hydration is relatively sufficient, indicating that it has good frost resistance:

[0078]

[0079] Example 4: A preparation process of a cured-soil building material, comprising the following steps:

[0080] (1) The following components were taken in the following proportions: sulphoaluminate cement 3.2 parts by weight, 42.5 ordinary Portland cement 4 parts by weight, polycarboxylate superplasticizer 0.05 parts by weight, water-based epoxy resin emulsion with a solid content of 40 wt.% 0.45 parts by weight, silane coupling agent (KH-550) 0.08 parts by weight, glycine betaine powder 0.6 parts by weight, hydroxyethyl cellulose 0.02 parts by weight. The above components were mixed until uniform to obtain a low-temperature flowable curing agent.

[0081] (2) The following components were taken in the following proportions: soil 73 parts by weight, low-temperature flowable curing agent of the present embodiment 14 parts by weight, mixing water 30 parts by weight. The above raw materials were mixed until uniform to obtain a cured-soil building material.

[0082] Performance test: the performance indexes of the cured soil building material prepared in this example were tested in the same way as in Example 1 above, wherein the XRD test results of the 12h hydration product are shown in Figure 10 , the compressive strength test results are shown in Figure 11 , and the results are shown in the following table. Meanwhile, it can be seen from the XRD test results that the cured soil building material of this example has almost no hydration reaction after low-temperature curing, and the hydration degree is very low, indicating that it has poor frost resistance:

[0083]

[0084] Example 5: A preparation process of a cured soil building material, comprising the following steps:

[0085] (1) Mix starch and water in a mass ratio of 1:8.5, stir uniformly, and then deoxygenate by passing N2. Then add maleic anhydride and potassium persulfate and heat to 60°C for 2 hours, the mass ratio of the modified starch, maleic anhydride, and potassium persulfate is 12:2.2:0.2. After completion, add anhydrous ethanol with twice the mass of the obtained reaction system for precipitation, then filter out the precipitate and grind, pass through a 75 mesh sieve, and obtain CMSS-g-MA powder.

[0086] (2) Mix glycine betaine and water, then add the CMSS-g-MA powder and heat to 60°C for 1.5 hours, the mass ratio of glycine betaine, water, and CMSS-g-MA powder is 1:6:3. After completion, the reaction liquid is spray dried to obtain GB / CMSS-g-MA powder, as shown in Figure 12 .

[0087] (3) Take the following proportions of components: sulphoaluminate cement 4 parts by weight, 42.5 ordinary portland cement 5 parts by weight, polycarboxylic acid water reducer 0.06 parts by weight, water-based epoxy resin emulsion with a solid content of 40wt.% 0.5 parts by weight, silane coupling agent (KH-570) 0.1 parts by weight, GB / CMSS-g-MA powder of this example 0.7 parts by weight, hydroxyethyl cellulose 0.025 parts by weight. Mix the above components uniformly to obtain a low-temperature fluid curing agent.

[0088] (4) Take the following proportions of components: soil 70 parts by weight, low-temperature fluid curing agent of this example 12 parts by weight, and mixing water 28 parts by weight. Mix the above raw materials uniformly to obtain a cured soil building material.

[0089] Performance test: the performance indexes of the cured soil building material prepared in this example were tested in the same way as in Example 1 above, wherein the XRD test results of the 12h hydration product are shown in Figure 13The compressive strength test is shown in Table 1. Figure 14 As shown in Table 1, the results are shown in the following table. At the same time, from the XRD test results, it can be seen that the cured soil building material of the present embodiment has a low degree of hydration after low temperature curing, and the hydration activity at low temperature is insufficient, and the frost resistance is reduced:

[0090]

[0091] Example 6: A preparation process of a cured soil building material, comprising the following steps:

[0092] (1) Mix starch with hot water at 80°C at a mass ratio of 1:5, then add alkali solution (10% mass fraction of sodium hydroxide solution), 2-bromoacetic acid sodium, and heat to 60°C for 1.5 hours, the mass ratio of 2-bromoacetic acid sodium, starch, and alkali solution is 0.52:2.2:0.43. After completion, adjust the reaction system to neutral with dilute hydrochloric acid, then add anhydrous ethanol for precipitation, the mass ratio of the reaction system to anhydrous ethanol is 1:1.7. After completion, filter out the precipitate and grind, then pass through a 100 mesh sieve to obtain modified starch.

[0093] (2) Mix glycine betaine with water, then add the modified starch and heat to 60°C for 2 hours, the mass ratio of glycine betaine, water, and modified starch is 1:6:2.5. After completion, the reaction liquid is spray dried to obtain GB / CMSS-g powder, as shown in Figure 15 .

[0094] (3) Take the following proportions of components: 3.2 parts by weight of sulphoaluminate cement, 4 parts by weight of 42.5 ordinary portland cement, 0.05 parts by weight of polycarboxylic acid water reducer, 0.45 parts by weight of water-based epoxy resin emulsion with a solid content of 40wt.%, 0.08 parts by weight of silane coupling agent (KH-550), 0.6 parts by weight of GB / CMSS-g powder of the present embodiment, and 0.02 parts by weight of hydroxyethyl cellulose. Mix the above components uniformly to obtain a low-temperature fluid curing agent.

[0095] (4) Take the following proportions of components: 73 parts by weight of soil, 14 parts by weight of low-temperature fluid curing agent of the present embodiment, and 30 parts by weight of mixing water. Mix the above raw materials uniformly to obtain a cured soil building material.

[0096] Performance test: the same as in Example 1 above, the performance indicators of the cured soil building material prepared in the present embodiment are tested, wherein: the XRD test results of 12h hydration product are shown in Table 1, and the compressive strength test is shown in Table 1. Figure 16 . Figure 17The results are shown in the following table. Meanwhile, from the XRD test results, it can be seen that the cured soil building material of the present embodiment has a low hydration degree after low-temperature curing, and the hydration activity at low temperature is insufficient, and the frost resistance is reduced:

[0097]

[0098] Example 7: A preparation process of a cured soil building material, comprising the following steps:

[0099] (1) Take the following proportions of components: 3 parts by weight of sulphoaluminate cement, 3 parts by weight of 42.5 ordinary portland cement, 0.4 parts by weight of water-based epoxy resin emulsion with a solid content of 43wt.%, 0.07 parts by weight of silane coupling agent (KH-560), 0.5 parts by weight of GB / CMSS-g-MA powder of the above-mentioned Example 2, and 0.01 parts by weight of hydroxyethyl cellulose. Mix the above components uniformly to obtain a low-temperature fluid curing agent.

[0100] (2) Take the following proportions of components: 78 parts by weight of soil, 15 parts by weight of the low-temperature fluid curing agent of the present embodiment, and 32 parts by weight of mixing water. Mix the above raw materials uniformly to obtain a cured soil building material.

[0101] Performance test: The performance indicators of the cured soil building material prepared in the present embodiment were tested in the same way as in the above-mentioned Example 1, wherein: the XRD test results of the 12h hydration product are shown in Figure 18 The compressive strength test is shown in Figure 19 The results are shown in the following table. Meanwhile, from the XRD test results, it can be seen that the cured soil building material of the present embodiment still maintains good hydration degree after low-temperature curing, and the hydration is sufficient, which indicates that its frost resistance is good. However, its setting rate is significantly accelerated, resulting in a significant decrease in fluidity, and thus the self-leveling ability is reduced:

[0102]

[0103] The above-mentioned only for the preferred embodiments of the present application, and not for limiting the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of a cryogenic fluid solidifying agent, characterized in that, Comprising the following steps: (1) starch is added to hot water and stirred to gelatinize, then lye, 2-bromo sodium acetate are added and heated to react; after completion, the reaction system is adjusted to neutral, then ethanol is added for precipitation, the precipitate is separated and ground to obtain modified starch; (2) the modified starch is added to water, stirred uniformly and deoxygenated; then maleic anhydride and persulfate are added and heated to react; after completion, ethanol is added for precipitation, the precipitate is separated and ground to obtain powder; (3) glycine betaine is added to water and stirred uniformly, then the powder obtained in step (2) is added and heated to react; after completion, the reaction liquid is spray dried to obtain modified betaine powder; (4) take sulphoaluminate cement, ordinary portland cement, polycarboxylate superplasticizer, water-based epoxy resin emulsion, silane coupling agent, modified betaine powder, hydroxyethyl cellulose as raw materials, mix them uniformly to obtain the low-temperature flowable curing agent.

2. The process for the preparation of cryogenic fluid solidification agent according to claim 1, characterized in that, In step (1), the mass ratio of the starch to hot water is 1:5-5.8; Alternatively, in step (1), the temperature of the hot water is 80-85℃.

3. The process for the preparation of cryogenic fluid solidification agent as claimed in claim 1 wherein, In step (1), the mass ratio of 2-bromo sodium acetate, starch, lye is 0.5-0.6:2-2.4:0.4-0.44; Alternatively, in step (1), the mass fraction of the lye is 10-12%.

4. The process for the preparation of cryogenic fluid solidification agent as claimed in claim 1 wherein, In step (1), the temperature of the heating reaction is 60-65℃, and the time is 1-2h; Alternatively, in step (1), the lye comprises at least one of sodium hydroxide, potassium hydroxide, ammonia water, lithium hydroxide; Alternatively, in step (1), the reaction system is adjusted to neutral by using at least one of dilute hydrochloric acid and dilute HBr; Alternatively, in step (1), the mass ratio of the reaction system to ethanol is 1:1.5-2; Alternatively, in step (1), the fineness of the modified starch is 75-100 mesh.

5. The process for the preparation of cryogenic fluid solidification agent as claimed in claim 1 wherein, In step (2), the mass ratio of the modified starch to water is 1:8-9; Alternatively, in step (2), the persulfate comprises at least one of ammonium persulfate and potassium persulfate.

6. The process for the preparation of cryogenic fluid solidification agent as claimed in claim 1 wherein, In step (2), the mass ratio of the modified starch, maleic anhydride, and persulfate is 10-12:1.8-2.2:0.1-0.2; Alternatively, in step (2), the temperature of the heating reaction is 60-65℃, and the time is 1-2h; Alternatively, in step (2), the fineness of the powder is 75-100 mesh.

7. The process for the preparation of cryogenic fluid solidification agent as claimed in claim 1 wherein, In step (3), the mass ratio of glycine betaine, water, and the powder obtained in step (2) is 1:6:2-3; Alternatively, in step (3), the temperature of the heating reaction is 60-65℃, and the time is 1-2h.

8. Process for the preparation of cryogenic fluid solidifying agents according to any one of claims 1 to 7, characterized in that, In step (4), the proportions of the components in the raw materials are as follows: sulphoaluminate cement 3-4 parts by weight, ordinary portland cement 3-5 parts by weight, polycarboxylate superplasticizer 0.05-0.06 parts by weight, water-based epoxy resin emulsion 0.4-0.5 parts by weight, silane coupling agent 0.07-0.1 parts by weight, modified betaine powder 0.5-0.7 parts by weight, and hydroxyethyl cellulose 0.01-0.025 parts by weight.

9. Process for the preparation of cryogenic fluid solidifying agents according to any one of claims 1-7, characterized in that, In step (4), the silane coupling agent comprises at least one of KH-550, KH-560, and KH-570; or, in step (4), the solid content of the aqueous epoxy resin emulsion is 40-43 wt.%.

10. A geoworking material, characterized by, The soil material 70-78 parts by weight, the low-temperature flow curing agent obtained by the preparation process of any one of claims 1-9 12-15 parts by weight, and the mixing water 22-27 parts by weight.

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