Dredged soil pneumatic mixed flow curing agent and preparation method thereof

Abstract

The invention relates to the technical field of dredged soil curing agents, in particular to a dredged soil pneumatic mixed flow curing agent and a preparation method thereof. The dredged soil pneumatic mixed flow curing agent is prepared from the following raw materials in parts by weight: 20 to 50 parts of cement, 10 to 40 parts of fly ash, 10 to 40 parts of mineral powder, 20 to 50 parts of quick lime, 0.01 to 0.1 part of retarder, 0.01 to 0.05 part of flocculant, 0.005 to 0.01 part of silane coupling agent and 0.1 to 0.3 part of hydrophobic adsorption type admixture. The hydrophobic adsorption type admixture, the silane coupling agent and the flocculating agent are doped into the curing agent raw materials at the same time and have a synergistic enhancement effect, so that the cohesiveness and the pumpability of curing agent slurry can be remarkably improved, the adaptability of the curing agent slurry and dredged soil in a pneumatic mixed flow process can be enhanced, the sensitivity to the water content of the dredged soil is reduced, and the curing agent has the advantages of being simple in preparation process and low in cost. The solidified soil is relatively stable in later-stage reinforcement, the solidifying agent is used in dredged soil pneumatic mixed-flow solidification production, the pumping constructability, the dispersion resistance in water and the hardening performance of the solidified soil can be remarkably improved, and the solidifying agent is suitable for filling projects such as sea reclamation and backfilling.

Description

Technical Field

[0001] The invention relates to the technical field of dredged soil solidifying agents, and in particular to a dredged soil pneumatic mixed flow solidifying agent and a preparation method thereof. Background Art

[0002] With the increasing efforts in the development of water resources along rivers and coasts, channel dredging, and water environment construction, my country's annual dredging volume has exceeded 1 billion cubic meters, making it the country with the largest annual output of dredged soil. However, the disposal of dredged soil has always been a major problem in the industry. For a long time, the disposal and management of dredged soil in my country has remained in an extensive state. A large amount of dredged soil is disposed of by dumping in designated sea areas, filling land, landfilling or stacking on land, which has a great impact on the ecological environment and poses safety hazards.

[0003] Therefore, the following new treatment methods have been derived: 1. Solidification of dredged sludge, specifically adding cement-based solidifying agent to dredged sludge, and using it for backfilling, embankment construction, etc. after sufficient mechanical stirring, which has achieved good results, but the disadvantage is that the solidification treatment cost of dredged soil is high and the treatment efficiency is low. 2. Pneumatic mixing solidification of dredged soil in pipes is considered to be an efficient treatment technology, that is, an appropriate amount of solidifying agent is injected into the dredged soil during pipeline transportation, and compressed air is input at the same time. Driven by the appropriate pressure airflow, the dredged soil and the solidifying agent swirl in the pipe and roll forward. The solidified soil is evenly mixed and does not occupy the site. It can be directly transported to the proposed filling site. This method is suitable for the preparation, transportation and filling of large volumes of solidified soil for hydraulic structures. However, the main problem with pneumatic mixed flow solidification of dredged soil in pipes is the solidification stability. On the one hand, dredged soil from different sources may have great differences in composition and properties, and the pneumatic mixing solidification method may have poor adaptability to dredged soil with certain special properties. On the other hand, due to the different components of dredged soil, especially the water content, higher requirements are placed on the adaptability and solidification stability between the solidifying agent and the dredged soil, and the strength of the dredged solidified soil often fluctuates greatly. Summary of the invention

[0004] The main purpose of the present invention is to provide a dredged soil pneumatic mixed flow solidifying agent and a preparation method thereof, aiming to improve the technical problems that the existing dredged soil pneumatic mixed flow solidification method has poor adaptability to dredged soil of different properties and the strength fluctuation of the obtained dredged solidified soil is large during pneumatic mixed flow solidification.

[0005] To achieve the above-mentioned purpose, the present invention provides a dredged soil pneumatic mixed flow curing agent, which comprises the following raw materials, by weight: 20 to 50 parts of cement, 10 to 40 parts of fly ash, 10 to 40 parts of mineral powder, 20 to 50 parts of quicklime, 0.01 to 0.1 parts of retarder, 0.01 to 0.05 parts of flocculant, 0.005 to 0.01 parts of silane coupling agent and 0.1 to 0.3 parts of hydrophobic adsorption type admixture.

[0006] Preferably, the preparation steps of the hydrophobic adsorption admixture include the following: S1. After mixing the long-chain alkyl siloxane and the unsaturated acid anhydride, adding a catalyst, heating to 80-110° C. for esterification reaction for 4-6 hours; cooling to below 40° C., adding an alkaline regulator to adjust the pH value to 6.0-7.0, and obtaining an unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate;

[0007] S2. The unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate, polyoxyethylene ether macromonomer and water are mixed and stirred evenly, the temperature is raised to 30 to 60 ° C, an oxidant is added, and then liquid A and liquid B are added dropwise thereto in sequence, and finally an alkaline regulator is added to adjust the pH value to 6.0 to 7.0 to obtain a hydrophobic adsorption admixture mother solution;

[0008] S3. The hydrophobic adsorption type admixture mother liquid is spray-dried to obtain the hydrophobic adsorption type admixture.

[0009] The alkaline regulator used in step S1 or S2 of this scheme can be a NaOH solution with a concentration of 20-40%. The spray drying temperature in step S3 is 120-150° C., and the obtained hydrophobic adsorption type additive is a powder.

[0010] Preferably, in step S1, the long-chain alkyl siloxane is one of dodecyltrimethoxysiloxane and octadecyltrimethoxysiloxane; the unsaturated acid anhydride is one of maleic anhydride and itaconic anhydride; and the catalyst is one of concentrated sulfuric acid and p-toluenesulfonic acid.

[0011] Preferably, in step S1, the weight ratio of the long-chain alkyl siloxane, the unsaturated acid anhydride and the catalyst is (25-30): (10-12): (0.005-0.01).

[0012] Preferably, in step S2, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether (HPEG) or methyl allyl polyoxyethylene ether (TPEG); the oxidant is hydrogen peroxide;

[0013] The weight ratio of the unsaturated carboxylic acid long-chain alkylsiloxane ester intermediate, the polyoxyethylene ether macromonomer, water and the oxidant is (16-20): (100-110): (30-180): (1.2-2).

[0014] Preferably, in step S2, the liquid A is composed of 6 to 12 parts of unsaturated carboxylic acid and 6 to 8 parts of water by weight, and the liquid A is added dropwise for 1 to 3 hours until all the prepared liquid A is added dropwise;

[0015] In parts by weight, the liquid B is composed of 0.1-0.5 parts of a reducing agent, 0.5-2 parts of a chain transfer agent and 10-15 parts of water. The liquid B is added dropwise for 1.5-3.5 hours until all the liquid B is added dropwise.

[0016] Preferably, in step S2, the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; and the chain transfer agent is one of thioglycolic acid or mercaptopropionic acid.

[0017] Preferably, the quicklime is calcareous quicklime; and the retarder is at least one of sodium gluconate, sugar, citric acid or boric acid.

[0018] Preferably, the flocculant is one of polyacrylamide or cellulose ether, and the molecular weight of the flocculant is 1 million to 3 million;

[0019] The silane coupling agent is one of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

[0020] In addition, the present invention also proposes a method for preparing the dredged soil pneumatic mixed flow curing agent as described in any of the above items, comprising the following steps: adding the cement, the fly ash, the mineral powder, the quicklime, the retarder, the flocculant, the silane coupling agent and the hydrophobic adsorption type admixture into a container by weight and stirring evenly to obtain the dredged soil pneumatic mixed flow curing agent.

[0021] Compared with the prior art, the dredged soil pneumatic mixed flow curing agent and the preparation method thereof of the present invention have the following beneficial effects:

[0022] 1. The hydrophobic adsorption admixture added to the curing agent of the present invention is a molecular structure of a multi-polymer of hydrophobic long-chain alkane trimethoxysiloxane-unsaturated dicarboxylic acid ester, an unsaturated carboxylic acid with strong adsorption of carboxylic acid functional groups, and a long side chain unsaturated polyoxyethylene ether. It is similar to the comb-like molecular structure of the polycarboxylic acid water reducer and plays the function of a water reducer. When preparing the curing agent slurry in the pneumatic mixed flow curing process, the amount of water can be reduced, and the fluidity and pumpability of the curing agent slurry can be improved. When the curing agent slurry is contacted and mixed with the dredged soil through pneumatic mixing in the pipe to prepare the cured soil, the hydrophobic adsorption type admixture can be adsorbed on the surface of the hydrophilic dredged soil particles due to its strong adsorption functional group. In an alkaline environment, as the hydrophobic long-chain alkane trimethoxysiloxane-carboxylate in the molecular structure of the admixture gradually hydrolyzes, the siloxane long-chain alkane small molecules are released. Since the silicon-oxygen bond has a strong hydrophilicity, it can continue to be adsorbed on the surface of the cementitious material, the hydration product and the dredged soil particles. At the same time, since the long-chain alkane is hydrophobic, the cured soil has a certain hydrophobicity.

[0023] 2. The curing agent raw material of the present invention also contains a silane coupling agent, which can cross-link and anchor the siloxane long-chain alkane small molecules released by the hydrolysis of the hydrophobic adsorption admixture on the surface of the cured soil and the cementitious material when the cured soil is prepared by pneumatic mixing, thereby enhancing the cementation of the cured soil, improving the strength of the cured soil, and making the cured soil have a certain hydrophobic effect, further enhancing the hydrophobicity of the cured soil.

[0024] 3. The curing agent raw material of the present invention also contains a flocculant, which can significantly enhance the cohesiveness and underwater anti-dispersion of the curing agent slurry. On the one hand, it enhances the full contact and mixing between the curing agent slurry and the dredged soil during the pneumatic mixing process; on the other hand, it improves the anti-dispersion of the solidified soil in water, makes it easy to precipitate and bleed, reduces the water-soil ratio and water-cement ratio in the solidified soil, enhances the strength of the solidified soil, and at the same time, the exuded water has a curing effect on the solidified soil, reduces the risk of drying, shrinkage and cracking of the solidified soil, and enhances the volume stability of the solidified soil.

[0025] In summary, the curing agent raw material of the present invention is simultaneously mixed with a hydrophobic adsorption admixture, a silane coupling agent and a flocculant, and the three play a synergistic enhancement role, which can not only significantly improve the cohesiveness and pumpability of the curing agent slurry, but also enhance the adaptability of the curing agent slurry and dredged soil under the pneumatic mixed flow process, reduce the sensitivity to the water content of the dredged soil, and the later enhancement of the cured soil is relatively stable. The curing agent of the present invention is used in the pneumatic mixed flow curing production of dredged soil, which can significantly improve the pumping construction performance, water anti-dispersion and hardening performance of the cured soil, and is suitable for land reclamation, backfill and other filling projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 It is a schematic diagram of preparing curing agent slurry in the embodiment or comparative example of the present scheme;

[0028] Figure 2 A schematic diagram of a pneumatic mixed flow solidification equipment for dredged soil for preparing solidified soil in an embodiment or comparative example of the present scheme;

[0029] Figure 3 This is the molecular structure diagram of the hydrophobic adsorption type admixture of this scheme;

[0030] Figure 4 This is the hydrolysis reaction diagram of the hydrophobic adsorption type admixture of this scheme in an alkaline environment;

[0031] Figure 5This is the cross-linking reaction diagram of the hydrophobic adsorption type admixture after hydrolysis under the action of silane coupling agent.

[0032] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] The invention provides a dredged soil pneumatic mixed flow curing agent, which comprises the following raw materials, measured by weight: 20-50 parts of cement, 10-40 parts of fly ash, 10-40 parts of mineral powder, 20-50 parts of quicklime, 0.01-0.1 parts of retarder, 0.01-0.05 parts of flocculant, 0.005-0.01 parts of silane coupling agent and 0.1-0.3 parts of hydrophobic adsorption type admixture.

[0036] Furthermore, the quicklime is calcium quicklime; the retarder is at least one of sodium gluconate, white sugar, citric acid or boric acid; the flocculant is one of polyacrylamide or cellulose ether, and the molecular weight of the flocculant is 1 to 3 million; the silane coupling agent is one of γ-methacryloxypropyltrimethoxysilane or γ-glycidyloxypropyltrimethoxysilane.

[0037] In addition to conventional cement, fly ash, mineral powder and quicklime, the curing agent raw materials in this scheme also include hydrophobic adsorption admixtures, silane coupling agents and flocculants. Among them, the hydrophobic adsorption admixture can improve the fluidity and pumpability of the curing agent slurry, so that the obtained solidified soil has a certain degree of hydrophobicity. The dredged soil curing agent also uses ultra-high molecular weight polyacrylamide as a flocculation component, which can enhance the chemical bond adsorption between the cementitious material, the hydration product and the dredged soil particles, improve the anti-dispersion of the solidified soil in water, and is easy to precipitate and bleed; as for the silane coupling agent in the raw material, it can cross-link and couple with the siloxane long-chain alkane small molecules after the hydrolysis of the hydrophobic adsorption admixture to form a network structure, so that the solidified soil prepared by pneumatic mixed flow curing is easy to precipitate and consolidate. The water exuded from the solidified soil reduces the water-soil ratio and water-cement ratio in the solidified soil, enhancing the strength of the solidified soil. At the same time, the exuded water plays a maintenance role on the solidified soil, reduces the risk of drying, shrinkage and cracking of the solidified soil, and enhances the volume stability of the solidified soil. The precipitated solidified soil further enhances the consolidation strength of the solidified soil due to the internal network cross-linking chemical adsorption and hydration reaction of the cementitious material.

[0038] In actual production, the cement of this scheme can be ordinary Portland cement; fly ash is preferably Grade II fly ash; and mineral powder is preferably Grade S95 mineral powder. Quicklime can be ordinary calcium quicklime, which participates in the hydration reaction, promotes the hydration of the cementitious material system, and adjusts the alkalinity of the curing agent paste. The retarder can be one or two of sodium gluconate, white sugar, citric acid, boric acid, etc., which is convenient for adjusting the setting time of the curing agent paste and ensuring the workability of the curing agent paste.

[0039] Furthermore, the preparation steps of the hydrophobic adsorption admixture include the following: S1. After mixing the long-chain alkyl siloxane and the unsaturated acid anhydride, adding a catalyst, heating to 80-110° C. for esterification reaction for 4-6 hours; cooling to below 40° C., adding an alkaline regulator to adjust the pH value to 6.0-7.0, and obtaining an unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate;

[0040] S2. The unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate, polyoxyethylene ether macromonomer and water are mixed and stirred evenly, the temperature is raised to 30 to 60 ° C, an oxidant is added, and then liquid A and liquid B are added dropwise thereto in sequence, and finally an alkaline regulator is added to adjust the pH value to 6.0 to 7.0 to obtain a hydrophobic adsorption admixture mother solution;

[0041] S3. The hydrophobic adsorption type admixture mother liquid is spray-dried to obtain the hydrophobic adsorption type admixture, and the concentration of the hydrophobic adsorption type admixture is 40 to 60%.

[0042] Wherein, in step S1, the long-chain alkyl siloxane is one of dodecyltrimethoxysiloxane or octadecyltrimethoxysiloxane; the unsaturated acid anhydride is one of maleic anhydride or itaconic anhydride; the catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid; the weight ratio of the long-chain alkyl siloxane, the unsaturated acid anhydride and the catalyst is (25-30): (10-12): (0.005-0.01).

[0043] In step S2, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether (HPEG) or methyl allyl polyoxyethylene ether (TPEG); the oxidant is hydrogen peroxide; the weight ratio of the unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate, the polyoxyethylene ether macromonomer (molecular weight of about 2400), water and the oxidant is (16-20): (100-110): (30-180): (1.2-2);

[0044] In parts by weight, the liquid A is composed of 6 to 12 parts of unsaturated carboxylic acid and 6 to 8 parts of water, and the liquid A is added for 1 to 3 hours, and the addition speed is controlled to be uniform; in parts by weight, the liquid B is composed of 0.1 to 0.5 parts of reducing agent, 0.5 to 2 parts of chain transfer agent and 10 to 15 parts of water, and the liquid B is added for 1.5 to 3.5 hours, and the addition speed is controlled to be uniform. The unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; and the chain transfer agent is one of thioglycolic acid or thiopropionic acid.

[0045] The alkaline regulator used in step S1 or S2 can be a NaOH solution with a concentration of 20-40%; the spray drying temperature in step S3 is 120-150° C., and the obtained hydrophobic adsorption additive is a powder.

[0046] In this scheme, long-chain alkyl siloxane and unsaturated acid anhydride are first subjected to esterification reaction under the condition of adding a catalyst to obtain an unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate; the unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate is then mixed with a polyoxyethylene ether macromonomer, etc., and after adding an oxidant, the special A liquid and B liquid of this scheme are added in sequence to obtain a hydrophobic adsorption type admixture mother liquor; the hydrophobic adsorption type admixture mother liquor is spray-dried to obtain a hydrophobic adsorption type admixture; through the above-mentioned functional polymer molecular structure design, a hydrophobic adsorption type admixture that can be adsorbed on the surface of cementitious materials and dredged soil particles is synthesized, and as it can be hydrolyzed in an alkaline environment, siloxane long-chain alkane small molecules are released. Since the silicon-oxygen-bond has a strong hydrophilicity, it can continue to be adsorbed on the cementitious material or the hydration product and the surface of dredged soil particles. At the same time, since the long-chain alkane has hydrophobicity, it has a certain hydrophobicity.

[0047] Figure 1The molecular structure of the hydrophobic adsorption admixture of this scheme is shown, wherein R1 is H, CH3 or CH2CH3; R2 is H, Na + or K + ; R3 is H or CH3; R4 is CH2CH3 or CH(CH3)2.

[0048] The present invention also proposes a method for preparing the pneumatic mixed flow curing agent for dredged soil as described in any of the above items, comprising the following preparation steps: adding the cement, the fly ash, the mineral powder, the quicklime, the retarder, the flocculant, the silane coupling agent and the hydrophobic adsorption type admixture into a container by weight and stirring evenly to obtain the pneumatic mixed flow curing agent for dredged soil. The preparation process of the pneumatic mixed flow curing agent for dredged soil is simple, the cost is low, and it can be well applied to industrial production.

[0049] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0050] Example 1

[0051] First, prepare the hydrophobic adsorption admixture, including the following steps:

[0052] S1. By weight, 25 parts of long-chain alkyl siloxane (dodecyl trimethoxysiloxane) and 10 parts of unsaturated acid anhydride (maleic anhydride) were added, 0.005 parts of catalyst (concentrated sulfuric acid) were added, the temperature was raised to 110°C for esterification reaction for 4 hours, and after cooling to 40°C, an alkaline regulator (40% NaOH solution) was added to adjust the pH value to 6.0 to prepare an unsaturated maleic acid dodecyl trimethoxysiloxane ester intermediate;

[0053] S2. 16 parts of unsaturated maleic acid dodecyl trimethoxysiloxane ester intermediate, 100 parts of polyether macromonomer (HPEG) and 30 parts of water were put into a reactor, stirred and heated to 30°C, and 1.2 parts of an oxidant (30% hydrogen peroxide solution) were added; then liquid A (6 parts of acrylic acid and 6 parts of water) was added dropwise for 3 hours, and then liquid B (0.1 parts of vitamin C, 0.5 parts of thioglycolic acid and 10 parts of water) was added dropwise for 3.5 hours, and liquids A and B were added dropwise at a uniform speed; finally, an alkaline regulator (40% NaOH solution) was added to adjust the pH value to 7.0 to prepare a 60% concentration of a hydrophobic adsorption admixture mother solution;

[0054] S3. Place the mother liquid of the hydrophobic adsorption type admixture in a spray dryer, and perform spray drying at a temperature of 120° C. to obtain a hydrophobic adsorption type admixture powder.

[0055] The preparation of the above-mentioned dredged soil pneumatic mixed flow curing agent comprises the following steps:

[0056] S01. By weight, add 20 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0057] S02. During the stirring process, 10 parts of fly ash, 10 parts of mineral powder, 20 parts of quicklime, 0.01 parts of retarder (sodium gluconate), 0.01 parts of flocculant (polyacrylamide), 0.005 parts of silane coupling agent (KH-302) and 0.1 parts of hydrophobic adsorption admixture were added in sequence;

[0058] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0059] Example 2

[0060] First, prepare the hydrophobic adsorption admixture, including the following steps:

[0061] S1. By weight, 30 parts of long-chain alkyl siloxane (octadecyl trimethoxy siloxane) and 12 parts of unsaturated acid anhydride (itaconic anhydride) were added, 0.01 parts of catalyst (methyl ethyl benzene sulfonic acid) were added, the temperature was raised to 80°C for esterification reaction for 6 hours, and after cooling to 40°C, an alkaline regulator (20% NaOH solution) was added to adjust the pH value to 6.0 to prepare an unsaturated itaconate octadecyl trimethoxy siloxane ester intermediate;

[0062] S2. 20 parts of unsaturated itaconate octadecyl trimethoxysiloxane intermediate, 110 parts of polyether macromonomer (TPEG) and 180 parts of water were put into a reaction kettle, stirred and heated to 60°C, and 2 parts of oxidant (30% hydrogen peroxide solution) were added; then liquid A (10 parts of methacrylic acid and 8 parts of water) was added dropwise for 1 hour, and then liquid B (0.5 parts of vitamin C, 2 parts of mercaptopropionic acid and 15 parts of water) was added dropwise for 1.5 hours, and liquid A and liquid B were added dropwise at a uniform speed; finally, an alkaline regulator (20% NaOH solution) was added to adjust the pH value to 6.0 to prepare a 40% concentration hydrophobic adsorption type admixture mother solution;

[0063] S3. Place the mother liquid of the hydrophobic adsorption type admixture in a spray dryer, and perform spray drying at 150° C. to obtain a hydrophobic adsorption type admixture powder.

[0064] The preparation of the above-mentioned dredged soil pneumatic mixed flow curing agent comprises the following steps:

[0065] S01. By weight, add 50 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0066] S02. During the stirring process, 40 parts of fly ash, 40 parts of mineral powder, 50 parts of quicklime, 0.1 parts of retarder (0.05 parts of sodium gluconate, 0.05 parts of sugar), 0.05 parts of flocculant (cellulose ether), 0.01 parts of silane coupling agent (KH-560), and 0.2 parts of hydrophobic adsorption admixture were added in sequence;

[0067] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0068] Example 3

[0069] First, prepare the hydrophobic adsorption admixture, including the following steps:

[0070] S1. By weight, 27 parts of long-chain alkyl siloxane (dodecyl trimethoxysiloxane) and 11 parts of (maleic anhydride) were added, 0.008 parts of catalyst (concentrated sulfuric acid) were added, the temperature was raised to 100 ° C for esterification reaction for 5 hours, and the temperature was lowered to 40 ° C, and an alkaline regulator (30% NaOH solution) was added to adjust the pH value to 6.5 to prepare an unsaturated maleic acid octadecyl trimethoxysiloxane intermediate;

[0071] S2. 18 parts of unsaturated maleic acid octadecyl trimethoxysiloxane ester intermediate, 105 parts of polyether macromonomer (TPEG) and 100 parts of water were put into a reactor, stirred and heated to 40°C, and 1.5 parts of an oxidant (30% hydrogen peroxide solution) were added; then liquid A (8 parts of acrylic acid, 6 parts of water) was added dropwise for 2.5 hours, and liquid B (0.3 parts of vitamin C, 1 part of mercaptopropionic acid and 12 parts of water) was added dropwise for 3 hours, and liquids A and B were added dropwise at a uniform speed; finally, an alkaline regulator (30% NaOH solution) was added to adjust the pH to 6.5 to prepare a 50% concentration hydrophobic adsorption admixture mother solution;

[0072] S3. Place the mother liquid of the hydrophobic adsorption type admixture in a spray dryer and perform spray drying at 130° C. to obtain a hydrophobic adsorption type admixture powder.

[0073] The preparation of the above-mentioned dredged soil pneumatic mixed flow curing agent comprises the following steps:

[0074] S01. By weight, add 30 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0075] S02. During the stirring process, 15 parts of fly ash, 15 parts of mineral powder, 20 parts of quicklime, 0.05 parts of retarder (boric acid), 0.03 parts of flocculant (cellulose ether), 0.008 parts of silane coupling agent (KH-302), and 0.2 parts of hydrophobic adsorption admixture were added in sequence;

[0076] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0077] Example 4

[0078] First, prepare the hydrophobic adsorption admixture, including the following steps:

[0079] S1. By weight, 25 parts of long-chain alkyl siloxane (octadecyl trimethoxy siloxane) and 10 parts of unsaturated acid anhydride (itaconic anhydride) were added, 0.01 parts of catalyst (p-toluenesulfonic acid) were added, the temperature was raised to 110° C. for esterification reaction for 6 hours, and after cooling to 40° C., an alkaline regulator (35% NaOH solution) was added to adjust the pH value to 7.0 to prepare an unsaturated itaconate octadecyl trimethoxy siloxane ester intermediate;

[0080] S2. 16 parts of unsaturated itaconate octadecyl trimethoxysiloxane ester intermediate, 100 parts of polyether macromonomer (TPEG) and 40 parts of water were put into a reactor, stirred and heated to 50°C, and 1.8 parts (30% concentration of hydrogen peroxide solution) were added; then liquid A (9 parts of acrylic acid, 6 parts of water) was added dropwise for 3 hours, and liquid B (0.4 parts of vitamin C, 1.5 parts of mercaptopropionic acid and 12 parts of water) was added dropwise for 3.5 hours; finally, an alkaline regulator (35% concentration of NaOH solution) was added to adjust the pH value to 7.0 to prepare a 60% concentration of a hydrophobic adsorption admixture mother solution;

[0081] S3. Place the mother liquid of the hydrophobic adsorption type admixture in a spray dryer and perform spray drying and powdering at a temperature of 140° C. to obtain a hydrophobic adsorption type admixture powder.

[0082] The preparation of the above-mentioned dredged soil pneumatic mixed flow curing agent comprises the following steps:

[0083] S01. By weight, add 40 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0084] S02. During the stirring process, 20 parts of fly ash, 20 parts of mineral powder, 40 parts of quicklime, 0.05 parts of retarder (citric acid), 0.04 parts of flocculant (polyacrylamide), 0.006 parts of silane coupling agent (KH-560) and 0.15 parts of hydrophobic adsorption admixture were added in sequence;

[0085] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0086] Comparative Example 1

[0087] The preparation steps and parameters in this comparative example are the same as those in Example 1, except that when preparing the pneumatic mixed flow curing agent for dredged soil, ordinary polycarboxylic acid water-reducing agent powder is used instead of the hydrophobic adsorption admixture powder.

[0088] Specifically, the preparation of the pneumatic mixed flow curing agent for dredged soil includes the following steps:

[0089] S01. By weight, add 20 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0090] S02. During the stirring process, 10 parts of fly ash, 10 parts of mineral powder, 20 parts of quicklime, 0.01 parts of retarder (sodium gluconate), 0.01 parts of flocculant (polyacrylamide), 0.005 parts of silane coupling agent (KH-302) and 0.1 parts of ordinary polycarboxylate water reducer powder were added in sequence;

[0091] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0092] Comparative Example 2

[0093] The preparation steps and parameters in this comparative example are the same as those in Example 1, except that no polyacrylamide flocculant is added to the formula for preparing the pneumatic mixed flow solidifying agent for dredged soil.

[0094] Specifically, the preparation of the pneumatic mixed flow curing agent for dredged soil includes the following steps:

[0095] S01. By weight, add 20 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0096] S02. During the stirring process, 10 parts of fly ash, 10 parts of mineral powder, 20 parts of quicklime, 0.01 parts of retarder (sodium gluconate), 0.005 parts of silane coupling agent (KH-302) and 0.1 parts of hydrophobic adsorption admixture were added in sequence;

[0097] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0098] Comparative Example 3

[0099] The preparation steps and parameters in this comparative example are the same as those in Example 1, except that: no KH-302 silane coupling agent is added to the formula for preparing the pneumatic mixed flow curing agent for dredged soil.

[0100] Specifically, the preparation of the pneumatic mixed flow curing agent for dredged soil includes the following steps:

[0101] S01. By weight, add 20 parts of cement to the feeding port of the powder mixing equipment and open the powder mixing stirring device;

[0102] S02. During the stirring process, 10 parts of fly ash, 10 parts of mineral powder, 20 parts of quicklime, 0.01 parts of retarder (sodium gluconate), 0.01 parts of flocculant (polyacrylamide) and 0.1 parts of hydrophobic adsorption admixture were added in sequence;

[0103] S03. After the addition is completed, stir for 2 hours to obtain a uniformly mixed dredged soil pneumatic mixed flow curing agent.

[0104] Comparative Example 4

[0105] The preparation steps and parameters in this comparative example are the same as those in Example 1, except that the long-chain alkyl fatty alcohol (dodecyl fatty alcohol or octadecyl fatty alcohol) is used to replace the long-chain alkyl siloxane (dodecyl or octadecyl trimethoxysiloxane) of the hydrophobic adsorption admixture, and the hydrophobic adsorption admixture in this scheme cannot be prepared.

[0106] The dredged soil pneumatic mixed flow curing agent prepared in the above Examples 1-4 and Comparative Examples 1-4 is firstly added with a certain amount of water to prepare a curing agent slurry (such as Figure 1 ), and then use dredged soil with a water content of 110% and use pneumatic mixed flow solidification equipment (such as Figure 2 ), the slurry injection pressure was fixed at 300 kPa, the curing agent injection pressure was fixed at 170 kPa, the cured soil was prepared, and the workability and hardening performance of the cured soil were tested. The basic properties of the dredged soil are shown in Table 1 below, and the test results of the cured soil prepared by the pneumatic mixed flow curing process on site are shown in Table 2. It should be noted that the amount of curing agent added is mainly controlled by a valve and air pressure, and the amount of curing agent added is about 9%. The blank group uses pure cement and ordinary polycarboxylic acid water reducer as the curing agent.

[0107] Table 1 Basic physical properties of dredged soil

[0108]

[0109] Table 2 Basic physical and mechanical properties of pneumatic mixed flow solidified soil

[0110]

[0111] It can be seen from the test results in Table 2 that for the pneumatic mixed flow solidification treatment of dredged soil, compared with the blank group of the solidifying agent using pure cement, the pneumatic mixed flow solidifying agent for dredged soil of Examples 1 to 4 of the present invention has better fluidity and cohesion, and greatly improves the air pressure turbulent mixing stability of the solidifying agent slurry and the dredged soil in the pipeline. At the same time, the prepared solidified soil has a large water seepage rate, good natural consolidation, good anti-dispersion in water, and high unconfined compressive strength, and is suitable for land reclamation, roadbed backfill and other projects.

[0112] Compared with Example 1, after ordinary polycarboxylate water-reducing agent is used to replace the hydrophobic adsorption admixture, the fluidity and pumping performance of the solidified soil slurry in the pipe are slightly worse than those in Example 1. The pumpability is general, and the pipe is occasionally easily blocked. The water seepage rate and unconfined compressive strength are all lower than those in Example 1.

[0113] Compared with Example 1, when no flocculant is used, the cohesiveness and fluidity of the solidified soil prepared by pneumatic mixed flow solidification are significantly lower than those in Example 1, indicating that when the flocculant of this scheme is used simultaneously with the hydrophobic adsorption type admixture in the pneumatic mixed flow solidification process, the dredged soil and the solidifying agent slurry can maintain good turbulent motion under the action of air pressure turbulence, so that the two are fully mixed, and the prepared solidified soil has good fluidity, cohesiveness, and resistance to dispersion in water, and has good sedimentation consolidation, high water seepage rate, and high unconfined compressive strength in the later stage.

[0114] Compared with Example 1, when no coupling agent is used, the main difference of Comparative Example 3 is that the water seepage rate and unconfined compressive strength of the solidified soil prepared by pneumatic mixed flow solidification are lower than those of Example 1, indicating that the coupling agent plays a cross-linking role between the dredged soil and the other raw materials of the solidifying agent, thereby enhancing the consolidation, density and hardening mechanical properties of the solidified soil.

[0115] In Comparative Example 4, compared with Example 1, long-chain alkyl fatty alcohol is used to replace the long-chain alkyl siloxane of the hydrophobic adsorption type admixture. The main difference is that the water seepage rate and unconfined compressive strength of the cured soil prepared by pneumatic mixed flow curing are lower than those in Example 1, indicating that the long-chain alkyl siloxane released after the hydrolysis of the long-chain alkyl siloxane ester in the molecular structure of the hydrophobic adsorption type admixture plays an adsorption and hydrophobic role, and plays a cross-linking role with the coupling agent, thereby enhancing the hydrophobic water seepage and hardening mechanical properties of the cured soil.

[0116] Example 5

[0117] The preparation steps and parameters in this embodiment are the same as those in Embodiment 1, except that the weight ratios of the long-chain alkyl siloxane, the unsaturated acid anhydride and the catalyst are different, as shown in the following table:

[0118]

[0119]

[0120] The dredged soil pneumatic mixed flow curing agent prepared in the above Example 5 is prepared into a curing agent slurry in the above manner, and then the cured soil is prepared in the above manner, and the workability and hardening performance of the cured soil are tested, as shown in the following table:

[0121] Table 3 Basic physical and mechanical properties of pneumatic mixed flow solidified soil

[0122]

[0123] It can be seen from the test results in Table 3 that when the weight ratio of the long-chain alkyl siloxane, the unsaturated acid anhydride and the catalyst in the present embodiment is limited to the preferred range of (26-30): (10.5-12): (0.007-0.01), the obtained hydrophobic adsorption admixture, when used as a curing agent, can further improve the fluidity, cohesiveness, water seepage rate, anti-dispersion and unconfined compressive strength of the obtained cured soil.

[0124] Example 6

[0125] The preparation steps and parameters in this embodiment are the same as those in Example 1, except that the weight ratios of the unsaturated carboxylic acid long-chain alkylsiloxane ester intermediate, the polyoxyethylene ether macromonomer, water and the oxidant are different, as shown in the following table:

[0126]

[0127] The dredged soil pneumatic mixed flow curing agent prepared in the above Example 6 is prepared into a curing agent slurry in the above manner, and then the cured soil is prepared in the above manner, and the workability and hardening performance of the cured soil are tested, as shown in the following table:

[0128] Table 4 Basic physical and mechanical properties of pneumatic mixed flow solidified soil

[0129]

[0130]

[0131] It can be seen from the test results in Table 4 that, compared with Example 1, when the weight ratio of the unsaturated carboxylic acid long-chain alkylsiloxane ester intermediate, the polyoxyethylene ether macromonomer, water and the oxidant in this scheme is limited to the preferred range of (18-20): (100-110): (35-180): (1.5-2), the obtained hydrophobic adsorption admixture, after being used as a curing agent, can further improve the fluidity, cohesiveness, water seepage rate, anti-dispersion and unconfined compressive strength of the obtained cured soil.

[0132] Example 7

[0133] The preparation steps and parameters in this embodiment are the same as those in Embodiment 1, except that the raw material dosage of the pneumatic mixed flow curing agent for dredged soil is different, see the following table:

[0134]

[0135] The dredged soil pneumatic mixed flow curing agent prepared in the above Example 7 was prepared into a curing agent slurry in the above manner, and then the cured soil was prepared in the above manner, and the workability and hardening performance of the cured soil were tested, as shown in the following table:

[0136] Table 5 Basic physical and mechanical properties of pneumatic mixed flow solidified soil

[0137]

[0138] It can be seen from the test results in Table 5 that, compared with Example 1, when the raw materials and dosage of the pneumatic mixed flow curing agent for dredged soil in this scheme are limited to 20-50 parts of cement, 15-40 parts of fly ash, 15-40 parts of mineral powder, 20-50 parts of quicklime, 0.05-0.1 parts of retarder, 0.02-0.05 parts of flocculant, 0.005-0.01 parts of silane coupling agent and 0.15-0.25 parts of hydrophobic adsorption type admixture, the obtained curing agent can further improve the fluidity, cohesiveness, water seepage rate, anti-dispersion and unconfined compressive strength of the obtained cured soil.

[0139] In addition to the above test data, the pneumatic mixed flow curing agent for dredged soil of the present invention has better applicability for dredged soil with different characteristics and water content than other cement-based curing agents on the market. The test selected three dredged soils with different characteristics and water content (see Table 6), and used the curing agent prepared in Example 1 to prepare the cured soil using the pneumatic mixed flow curing process. The properties of the prepared cured soil are shown in Table 7.

[0140] Table 6 Basic physical properties of dredged soil with different characteristics

[0141]

[0142]

[0143] Table 7 Basic physical and mechanical properties of stabilized soil prepared by pneumatic mixing process for different dredged soils

[0144]

[0145] It can be seen from Table 7 that the curing agent prepared by the present invention has better adaptability to dredged soil with the same characteristics and moisture content than the commercially available cement-based curing agent. The cured soil prepared by the pneumatic mixed flow curing process can be pumped smoothly in the pipeline with good fluidity. The cured soil has good cohesiveness, water seepage and anti-dispersion, and has high unconfined compressive strength.

[0146] The above embodiments are only preferred implementation modes of the present invention, and do not limit the patent scope of the present invention. The dredged soil pneumatic mixed flow curing agent mentioned in the present invention is not limited to the above-mentioned ones. Therefore, the above embodiments cannot be regarded as limiting the protection scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A pneumatic mixed flow curing agent for dredged soil, characterized in that: The raw materials are as follows, measured in parts by weight: 20-50 parts of cement, 10-40 parts of fly ash, 10-40 parts of mineral powder, 20-50 parts of quicklime, 0.01-0.1 parts of retarder, 0.01-0.05 parts of flocculant, 0.005-0.01 parts of silane coupling agent and 0.1-0.3 parts of hydrophobic adsorption admixture.

2. The dredged soil pneumatic mixed flow curing agent according to claim 1, characterized in that: The preparation steps of the hydrophobic adsorption type admixture include the following: S1. After mixing the long-chain alkyl siloxane and the unsaturated acid anhydride, a catalyst is added, and the temperature is raised to 80-110° C. for esterification reaction for 4-6 hours; the temperature is lowered to below 40° C., and an alkaline regulator is added to adjust the pH value to 6.0-7.0 to obtain an unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate; S2. The unsaturated carboxylic acid long-chain alkyl siloxane ester intermediate, polyoxyethylene ether macromonomer and water are mixed and stirred evenly, the temperature is raised to 30 to 60 ° C, an oxidant is added, and then liquid A and liquid B are added dropwise thereto in sequence, and finally an alkaline regulator is added to adjust the pH value to 6.0 to 7.0 to obtain a hydrophobic adsorption admixture mother solution; S3. The hydrophobic adsorption type admixture mother liquid is spray-dried to obtain the hydrophobic adsorption type admixture.

3. The dredged soil pneumatic mixed flow curing agent according to claim 2, characterized in that: In step S1, the long-chain alkyl siloxane is one of dodecyltrimethoxysiloxane and octadecyltrimethoxysiloxane; the unsaturated acid anhydride is one of maleic anhydride and itaconic anhydride; and the catalyst is one of concentrated sulfuric acid and p-toluenesulfonic acid.

4. A dredged soil pneumatic mixed flow curing agent according to claim 2 or 3, characterized in that: In step S1, the weight ratio of the long-chain alkyl siloxane, the unsaturated acid anhydride and the catalyst is (25-30): (10-12): (0.005-0.01).

5. The pneumatic mixed flow curing agent for dredged soil according to claim 2, characterized in that: In step S2, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether and methyl allyl polyoxyethylene ether; the oxidant is hydrogen peroxide; The weight ratio of the unsaturated carboxylic acid long-chain alkylsiloxane ester intermediate, the polyoxyethylene ether macromonomer, water and the oxidant is (16-20): (100-110): (30-180): (1.2-2).

6. A dredged soil pneumatic mixed flow curing agent according to claim 2 or 5, characterized in that: In step S2, the liquid A is composed of 6 to 12 parts of unsaturated carboxylic acid and 6 to 8 parts of water by weight, and the time for completing the dropwise addition of the liquid A is 1 to 3 hours; In parts by weight, the liquid B is composed of 0.1 to 0.5 parts of a reducing agent, 0.5 to 2 parts of a chain transfer agent and 10 to 15 parts of water. The time for completing the dropwise addition of the liquid B is 1.5 to 3.5 hours.

7. The dredged soil pneumatic mixed flow curing agent according to claim 6, characterized in that: In step S2, the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; and the chain transfer agent is one of thioglycolic acid or mercaptopropionic acid.

8. The dredged soil pneumatic mixed flow curing agent according to claim 1, characterized in that: The quicklime is calcium quicklime; the retarder is at least one of sodium gluconate, sugar, citric acid or boric acid.

9. The dredged soil pneumatic mixed flow curing agent according to claim 1, characterized in that: The flocculant is one of polyacrylamide or cellulose ether, and the molecular weight of the flocculant is 1 million to 3 million; The silane coupling agent is one of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

10. A method for preparing the pneumatic mixed flow curing agent for dredged soil according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: adding the cement, the fly ash, the mineral powder, the quicklime, the retarder, the flocculant, the silane coupling agent and the hydrophobic adsorption type admixture into a container by weight and stirring evenly to obtain the dredged soil pneumatic mixed flow curing agent.

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