Coastal soft soil anti-chlorine salt erosion-deliquescence-resistant composite curing material and curing method based on coastal soft soil anti-chlorine salt erosion-deliquescence-resistant composite curing material

Abstract

The invention discloses a coastal soft soil anti-chlorine salt erosion-deliquescence composite curing material and a curing method based on the coastal soft soil anti-chlorine salt erosion-deliquescence composite curing material, and belongs to the technical field of soft soil curing, the coastal soft soil anti-deliquescence composite curing material comprises, by mass, 6.1-10.7 parts of an anti-deliquescence system, 67-88 parts of a core gel system, 12.5-19.5 parts of an anti-erosion system, and 0.78-1.22 parts of an auxiliary modification system; the deliquescence-resistant system is prepared from 5 to 8 parts of modified bentonite, 0.8 to 1.2 parts of polymer fiber and 0.3 to 0.5 part of silane coupling agent; the anti-erosion system is prepared from 8 to 12 parts of calcined dolomite powder, 3 to 5 parts of hydrated calcium silicate micro powder and 1.5 to 2.5 parts of nano silicon dioxide. The coastal soft soil deliquescence-resistant composite curing material disclosed by the invention has chlorine salt erosion resistance and deliquescence resistance.

Description

Technical Field

[0001] This invention belongs to the field of soft soil solidification technology, specifically relating to a composite solidification material for coastal soft soil that resists chloride salt erosion and deliquescence, and a solidification method based thereon. It can be widely used in soft soil foundation reinforcement projects such as roadbeds, port storage yards, and building foundations in coastal areas. Background Technology

[0002] While existing composite curing materials attempt to improve performance by adding industrial waste such as slag and fly ash, they fall short in synergistically enhancing resistance to chloride erosion and deliquescence. On the one hand, chlorides readily react chemically with the curing products, generating soluble salts that reduce the density of the cured body. On the other hand, repeated moisture penetration and evaporation during deliquescence create capillary channels within the cured body, accelerating chloride migration and erosion. Therefore, there is an urgent need to develop a composite curing material and corresponding curing method that can simultaneously resist chloride erosion, inhibit deliquescence, and is suitable for the characteristics of coastal soft soil.

[0003] Coastal soft soil, due to long-term seawater infiltration, is characterized by high natural water content (typically 50%–90%), large porosity (1.2–2.0), and low shear strength (10–30 kPa). Furthermore, the soil has a high chloride content (chloride ion mass fraction 0.3%–1.5%), leading to frequent deliquescence. Traditional soft soil stabilization materials, primarily composed of cement and lime, are susceptible to chloride erosion in coastal environments, causing salt expansion cracks within the solidified body. Simultaneously, deliquescence damages the structural integrity of the solidified body, resulting in subsequent strength reduction and decreased bearing capacity, severely impacting engineering stability and durability.

[0004] Chinese patent CN119080453A discloses a cementing material for solidifying silty soft soil with high water content, its preparation method, and its application. The cementing material comprises silicate cement, mineral powder, bentonite, zeolite powder, metakaolin, and an activator, mixed in a specific ratio for solidifying silty soft soil with high water content. It improves the solidification strength and impermeability through rapid hydration reaction and pozzolanic effect. However, this solidification material struggles to simultaneously possess resistance to chloride erosion and deliquescence. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a composite curing material for coastal soft soil that is resistant to chloride salt erosion and deliquescence, and a curing method based thereon, so as to solve the technical problem that existing curing materials are difficult to simultaneously possess both chloride salt erosion resistance and deliquescence resistance.

[0006] In this invention, the solidified body refers to a hardened solid material formed by mixing a composite solidification material with coastal soft soil and then subjecting it to a series of physicochemical reactions and processes (such as stirring, vibration, pouring and curing).

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a deliquescence-resistant composite solidification material for coastal soft soil, comprising, by weight parts: 6.1-10.7 parts of a deliquescence-resistant system, 67-88 parts of a core cementing system, 12.5-19.5 parts of an erosion-resistant system, and 0.78-1.22 parts of an auxiliary modification system; The anti-deliquescence system comprises 5-8 parts modified bentonite, 0.8-1.2 parts polymer fiber, and 0.3-0.5 parts silane coupling agent; the anti-erosion system comprises 8-12 parts calcined dolomite powder, 3-5 parts hydrated calcium silicate micro powder, and 1.5-2.5 parts nano silica.

[0008] Preferably, the modified bentonite is obtained by modifying calcium-based bentonite with a cationic surfactant.

[0009] Preferably, the polymer fiber is a short polyetheretherketone fiber. 4. The coastal soft soil anti-deliquescence composite curing material according to claim 1, characterized in that the core cementing system, by mass parts, comprises 35-45 parts of silicate cement, 12-18 parts of metakaolin, and 20-25 parts of granulated blast furnace slag.

[0010] Preferably, the auxiliary modification system comprises, by mass parts, 0.08-0.12 parts of triethanolamine, 0.2-0.3 parts of calcium lignosulfonate, and 0.5-0.8 parts of anhydrous sodium sulfate.

[0011] This invention also provides a method for preparing the above-mentioned anti-deliquor composite solidification material for coastal soft soil, comprising the following steps: 1) Pretreatment of the core cementing system, anti-erosion system, anti-deliquescence system, and auxiliary modification system; 2) Mix the core cementing system, anti-erosion system, anti-deliquescence system and auxiliary modification system in sequence. First mix the core cementing system, then add the anti-erosion system, then add the anti-deliquescence system, and finally add the auxiliary modification system. Mix evenly to obtain the anti-deliquescence composite solidification material for coastal soft soil.

[0012] More preferably, the pretreatment includes: activation treatment of granulated blast furnace slag, including calcination and grinding, to achieve a specific surface area of ​​450 m². 2 / kg -500m 2 / kg; modified calcium-based bentonite was obtained by cationic surfactant treatment; and polyether ether ketone short fibers were surface treated.

[0013] This invention also provides a method for solidifying coastal soft soil using the above-mentioned anti-deliquescence composite solidification material, comprising the following steps: a) Remove impurities from the surface layer of coastal soft soil, break the soft soil to a particle size ≤20mm, and adjust the moisture content to 45%-55%; b) Add the composite curing material to the coastal soft soil treated in step a) in three portions, at a weight of 18%-22% of the coastal soft soil mass. Stir and vibrate after each addition to obtain a mixture. Then pour the mixture into the construction area. c) After pouring, cover with a film to retain moisture, carry out initial, intermediate and late curing, and apply a protective coating after curing.

[0014] Preferably, in step a), if the chloride ion mass fraction of the soft soil is >1.0%, 2%-3% of the mass of the coastal soft soil zeolite powder is added for preliminary adsorption, and the mixture is left to stand for 30 minutes.

[0015] Preferably, in step b), the composite curing material is added in three parts: the first part is 50% of the mass of the coastal soft soil, and the mixture is stirred for 12 minutes; the second part is 30% of the mass of the coastal soft soil, and the mixture is stirred for 10 minutes; the third part is 20% of the mass of the coastal soft soil, and the mixture is stirred for 8 minutes.

[0016] Preferably, in step c), the initial curing is carried out by covering with a film for 1-7 days at an ambient temperature of 15-25℃; the intermediate curing is carried out by spraying for 8-21 days, with spraying twice a day; the final curing is carried out by natural curing for 22-28 days; after curing, a penetrating fluorocarbon coating is applied with a coating thickness of 30μm-50μm.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a deliquescence-resistant composite solidification material for coastal soft soil, wherein the Ca²⁺ in the calcined dolomite powder is present in the anti-erosion system. + Mg² + It combines with chloride ions in the soil to form stable chloride salt compounds, reducing the erosion of the solidified body by chloride ions. Hydrated calcium silicate micropowder and nano-silica refine the internal pore size of the solidified body, forming a dense, impermeable structure that blocks chloride ion migration. In the anti-deliquescence system, modified bentonite has excellent water absorption and retention properties, which can regulate the internal moisture balance of the solidified body and prevent repeated water migration during deliquescence. Silane coupling agents improve the interfacial bonding force between the fiber and the cementitious matrix, enhancing the anti-deliquescence stability. Therefore, the anti-deliquescence composite solidification material for coastal soft soil possesses both chloride salt erosion resistance and deliquescence resistance.

[0018] Furthermore, modified bentonite, through modification with cationic surfactants, enhances its organic compatibility and dispersibility in the soil, resulting in better hydrophobic modification and pore-filling effects.

[0019] Furthermore, the polyetheretherketone short fibers form a three-dimensional network structure in the cured body, which enhances the overall structural integrity and inhibits cracking caused by deliquescence.

[0020] Furthermore, in the core cementing system, ordinary silicate cement provides basic cementing strength, metakaolin reacts with cement hydration products to generate more hydrated calcium silicate gel, which fills the soil pores; after activation, the active components of granulated blast furnace slag combine with hydration products, which improves the density of the solidified body.

[0021] Furthermore, in the auxiliary modification system, triethanolamine and anhydrous sodium sulfate accelerate the hydration reaction process, while calcium lignosulfonate optimizes the workability of the coastal soft soil anti-deliquor composite curing material, ensuring construction quality.

[0022] This invention also provides a method for preparing the above-mentioned coastal soft soil anti-deliquor composite curing material. By activating and grinding granulated blast furnace slag, its specific surface area and reactivity are significantly improved, enabling it to play a more complete role in the curing process. Modification of bentonite and surface treatment of polyether ether ketone short fibers ensure the effective realization of the functions of each component. The specific order of adding the core cementing system, anti-erosion system, anti-deliquor system and auxiliary modification system is specified, which is conducive to the uniform dispersion of each component, avoids agglomeration, and ensures the uniformity and stability of the final product performance.

[0023] This invention also provides a method for solidifying coastal soft soil using the aforementioned anti-deliquity composite solidification material. By removing impurities, crushing, and adjusting the moisture content of the coastal soft soil, it is beneficial to mix it evenly with the anti-deliquity composite solidification material. The composite solidification material is added in three stages and stirred thoroughly to ensure that the composite solidification material is mixed evenly with the coastal soft soil and to avoid local failure. The curing system of covering and moisturizing and segmented curing provides ideal conditions for the hydration reaction and ensures healthy strength development.

[0024] Furthermore, for coastal soft soil with excessive chloride ion content, zeolite powder was added in advance to reduce the concentration of free chloride ions by utilizing its adsorption properties, thereby alleviating the erosion pressure of subsequent composite curing materials.

[0025] Furthermore, the precise proportions and mixing times for the three additions were clearly defined and solidified through process parameters to ensure the mixing effect.

[0026] Furthermore, the phased maintenance of initial moisturizing, mid-term spraying, and later natural application matches the different stages of strength development; finally, the application of a penetrating fluorocarbon coating forms an effective surface protective layer, further enhancing the long-term durability and resistance to environmental erosion of the cured body. Detailed Implementation

[0027] To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0029] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0030] In this article, unless otherwise specified, the terms “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of”. For example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a”.

[0031] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0032] This invention provides a composite curing material, which consists of four parts: a core cementing system, an anti-erosion system, an anti-deliquescence system, and an auxiliary modification system. The specific components and technical parameters of each system, by mass percentage, are as follows: 1. Core cementitious system (total mass parts: 67-88 parts) 42.5 grade ordinary Portland cement: 35-45 parts. Use 42.5 grade ordinary Portland cement conforming to GB175-2007 "General Portland Cement" standard, wherein the mass fraction of tricalcium silicate (C3S) is ≥55%, dicalcium silicate (C2S) is ≥15%, tricalcium aluminate (C3A) is ≤8%, and tetracalcium aluminoferrite (C4AF) is ≤12%; initial setting time is ≥45 min, final setting time is ≤600 min; 3-day compressive strength is ≥17.0 MPa, 28-day compressive strength is ≥42.5 MPa; specific surface area is 300-350 m². 2 / kg, with a free calcium oxide mass fraction ≤1.5%, ensuring it possesses basic gel strength and stable hydration reaction characteristics.

[0033] Metakaolin: 12-18 parts. Metakaolin is prepared by calcining kaolin at 700-800℃ for 2-3 hours, wherein the mass fraction of silicon dioxide (SiO2) is ≥50%, the mass fraction of aluminum oxide (Al2O3) is ≥35%, and the total mass fraction of SiO2 and Al2O3 is ≥85%; the loss on ignition is ≤5%, the moisture content is ≤2%; the specific surface area is ≥500m² / kg, and the particle size distribution is D50≤10μm and D90≤20μm, ensuring that it has high pozzolanic activity and can fully react with cement hydration products.

[0034] S95 grade granulated blast furnace slag: 20-25 parts. Select S95 grade blast furnace slag conforming to GB / T18046-2017 "Granulated Blast Furnace Slag Powder for Cement, Mortar and Concrete", wherein the mass fraction of silicon dioxide (SiO2) is ≥30%, the mass fraction of aluminum oxide (Al2O3) is ≥15%, and the mass fraction of calcium oxide (CaO) is ≥35%; the 28-day activity index is ≥95%, the fluidity ratio is ≥90%, and the specific surface area is 400-450 m². 2 / kg, moisture content ≤1.0%, density 2.8~3.0g / cm³ 3 Its reactivity can be further enhanced after subsequent activation treatment.

[0035] 2. Anti-corrosion system (total mass parts: 12.5~19.5 parts) Calcined dolomite powder: 8-12 parts. Natural dolomite (main component is CaCO3) is selected. MgCO3 is prepared by calcining at 900~1000℃ for 2.5~3 hours, with the heating rate controlled at 10℃ / min during calcination. After holding at the temperature, it is naturally cooled to room temperature. The mass fraction of calcium oxide (CaO) is ≥30%, the mass fraction of magnesium oxide (MgO) is ≥25%, and the total mass fraction of CaO and MgO is ≥55%. The loss on ignition is ≤8%. The particle size is ground to D50≤20μm and D90≤50μm by an air jet mill to ensure that it can fully react with chloride ions in the soil to form stable compounds.

[0036] Calcium silicate hydrate micro powder: 3-5 parts. Calcium silicate hydrate (CSH) micro powder prepared by chemical synthesis, wherein the mass fraction of CaO is ≥40%, the mass fraction of SiO2 is ≥35%, and the Ca / Si molar ratio is 1.5-2.0; the average particle size is controlled at 0.5-1 μm using ultrafine grinding equipment, and the specific surface area is ≥80 m². 2 / g; hydration activity index (28d, compared with the benchmark cement) ≥95%, moisture content ≤1.0%, can fill the tiny pores inside the solidified body and improve impermeability.

[0037] Nano-silica: 1.5~2.5 parts. Nano-silica prepared by gas-phase method, with a purity ≥99.5%, of which SiO2 mass fraction ≥99.5%, and total impurity (Fe2O3, Al2O3, etc.) mass fraction ≤0.5%; average particle size 20~50nm, specific surface area ≥150m². 2 / g, loose bulk density is 0.15~0.25g / cm³ 3 With a pH value of 6-8, it exhibits good dispersibility and no obvious agglomeration. It can refine the pore structure of the solidified body and enhance its resistance to chloride ion penetration.

[0038] 3. Anti-deliquescence system (total mass parts: 6.1~10.7 parts) Modified bentonite: 5-8 parts. Using calcium-based bentonite as raw material, it was modified with a cationic surfactant: Calcium-based bentonite (montmorillonite mass fraction ≥80%, cation exchange capacity ≥60mmol / 100g) was added to a 10% aqueous solution of hexadecyltrimethylammonium chloride (purity ≥98%), and stirred in a 60℃ constant temperature water bath at 300r / min for 3 hours. After the reaction, the mixture was filtered using a plate and frame filter press, and the filter cake was dried in a 110℃ forced-air drying oven until the moisture content was ≤2%. It was then pulverized using a universal pulverizer and passed through a 200-mesh sieve (sieve aperture size 75μm). The modified bentonite had a cation exchange capacity ≥80mmol / 100g, a water absorption rate ≤150%, and an expansion ratio ≤10 times, exhibiting excellent moisture adjustment capabilities.

[0039] Polyetheretherketone (PEEK) short fibers: 0.8~1.2 parts. Extruded PEEK short fibers are selected, with fiber length controlled at 3~5 mm and diameter at 20~30 μm by a pelletizer; tensile strength ≥150 MPa, elongation at break ≥15%, elastic modulus ≥3.5 GPa; chemical corrosion resistance meets the Class 1 standard in GB / T11791-2008 "Test Method for Resistance of Plastics to Liquid Chemical Reagents", showing no obvious corrosion after immersion in 5% sodium chloride solution for 30 days; the fiber surface is plasma treated (argon atmosphere, power 300W, treatment time 3 minutes) to improve surface roughness and activity, and enhance the interfacial bonding with the gel matrix.

[0040] Silane coupling agent KH-550: 0.3~0.5 parts. Industrial grade silane coupling agent KH-550 is selected, wherein the mass fraction of γ-aminopropyltriethoxysilane is ≥98%, the boiling point is 217~218℃, and the density (25℃) is 0.940~0.946 g / cm³. 3 The refractive index (25℃) is 1.420~1.425; it has good water solubility, and there is no stratification when the mass fraction of the solubility in water is ≤5%, which can improve the interfacial compatibility between polyetheretherketone short fibers and the gel matrix.

[0041] 4. Auxiliary modification system (total mass parts: 0.78~1.22 parts) Triethanolamine: 0.08~0.12 parts. Industrial grade triethanolamine with a purity ≥99%, wherein the mass fraction of triethanolamine is ≥99%, and the total mass fraction of monoethanolamine and diethanolamine is ≤1%; boiling point is 335℃, and density (25℃) is 1.124~1.129 g / cm³. 3 It has a refractive index (25℃) of 1.482~1.485; it is a colorless and transparent liquid with no obvious odor, and can accelerate the cement hydration reaction process and improve early strength.

[0042] Calcium lignosulfonate: 0.2~0.3 parts. Calcium lignosulfonate, a byproduct of the pulping industry, is selected, with a calcium lignosulfonate mass fraction ≥85%, a water-insoluble matter mass fraction ≤1.0%, a pH value of 6~8, a moisture content ≤5%, and a fineness passing through an 80-mesh sieve (sieve aperture size 180μm) with a passing rate ≥95%; a water reduction rate ≥8%, which can improve the workability of the cured material slurry and reduce water consumption.

[0043] Anhydrous sodium sulfate: 0.5~0.8 parts. Industrial grade anhydrous sodium sulfate with a purity ≥99%, of which Na₂SO₄ mass fraction ≥99% and impurities (Cl₂) are... - Fe 3+ The total mass fraction of the solidified material is ≤1%; the moisture content is ≤0.5%; and the particle size passes through a 100-mesh sieve (150μm aperture) with a passing rate of ≥98%. It can be used as an early strength agent to promote the formation of hydration products and improve the early strength of the solidified body.

[0044] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" represents weight percentage, "parts" represents parts by weight, and "ratio" represents weight proportion.

[0046] Example 1 Core cementitious system: 67 parts (35 parts of 42.5 grade ordinary Portland cement, 12 parts of metakaolin, and 20 parts of S95 grade granulated blast furnace slag) Anti-erosion system: 12.5 parts (8 parts calcined dolomite powder, 3 parts hydrated calcium silicate micro powder, 1.5 parts nano silica) Anti-deliquescence system: 6.1 parts (5 parts modified bentonite, 0.8 parts polyetheretherketone short fiber, 0.3 parts silane coupling agent KH-550) Auxiliary modification system: 0.78 parts (0.08 parts triethanolamine, 0.2 parts calcium lignosulfonate, 0.5 parts anhydrous sodium sulfate) Total weight: 86.38 portions This embodiment provides a method for preparing the above-mentioned composite curing material. The composite curing material is prepared using an industrial-grade continuous production process, relying on a production line flow of "pretreatment-segmented mixing-quality testing-sealed storage". The specific steps and parameter control are as follows: 1. Raw material pretreatment stage Granulated blast furnace slag activation treatment: S95 grade granulated blast furnace slag is fed into a vertical continuous calcining furnace, which is divided into a preheating section (temperature 400~500℃, residence time 30min), an activation section (temperature 850℃, residence time 2.5h), and a cooling section (cooled to room temperature by introducing cold air, residence time 1h). After calcination, the slag is fed into a ball mill (grinding media is agate balls, ball-to-material ratio is 8:1). During grinding, the mill speed is controlled at 300r / min, and the grinding time is 4 hours. After grinding, the slag is screened by an air classifier to ensure that the specific surface area of ​​the slag powder reaches 450~500m². 2 / kg, with a particle size distribution of D50≤15μm and D90≤30μm; the activated slag powder is sent into the storage silo, and inert gas (nitrogen purity ≥99.9%) is introduced into the storage silo to prevent the slag powder from getting damp and clumping.

[0047] Bentonite modification treatment: Start the modification reactor (10m³ volume) 3(Equipped with a stirring and temperature control system), add 500 kg of calcium-based bentonite and 2000 L of deionized water to the reactor, start stirring (200 r / min), and heat to 60 °C; dissolve 50 kg of hexadecyltrimethylammonium chloride in 500 L of deionized water to prepare a 10% (w / w) aqueous solution, and slowly inject it into the reactor at a rate of 5 L / min using a metering pump. After injection, continue stirring for 3 hours (maintaining a stirring speed of 200 r / min and a temperature of 60 °C); after the reaction is complete, The slurry is fed into a plate and frame filter press (filtration pressure 0.6MPa, filtration temperature 60℃) to obtain filter cake (moisture content ≤30%). The filter cake is then fed into a belt dryer (drying temperature 110℃, drying air velocity 1.5m / s, residence time 30min) and dried until the moisture content is ≤2%. The dried modified bentonite is then fed into a universal pulverizer (speed 3000r / min) for pulverization. After pulverization, the material is passed through a 200-mesh vibrating screen (screen material is stainless steel, vibration frequency 50Hz, amplitude 5mm) and then stored in a sealed storage tank.

[0048] Surface treatment of polyetheretherketone (PEEK) short fibers: 100 kg of PEEK short fibers are evenly spread on the conveyor belt of the plasma treatment machine (conveyor belt speed 0.5 m / min). Argon gas (flow rate 5 L / min, purity ≥ 99.99%) is introduced into the treatment machine. The treatment power is set to 300 W and the treatment time is 3 minutes to ensure that the fiber surface is uniformly treated by plasma. The treated fibers are immediately sent to a vacuum storage tank (vacuum degree ≤ -0.08 MPa) to prevent surface oxidation or moisture absorption.

[0049] Other raw material pretreatment: Metakaolin, calcined dolomite powder, hydrated calcium silicate micro powder, and nano silica are respectively fed into their respective air jet mills (milling pressure 0.8MPa, classifying wheel speed 10000r / min), and after being milled to meet the particle size requirements, they are stored in the corresponding sealed storage silos; Triethanolamine and silane coupling agent KH-550 are respectively loaded into storage tanks with heating jackets (heating temperature 30℃ to prevent low-temperature solidification), and level gauges and metering pumps are installed on the storage tanks to ensure accurate feeding; Calcium lignosulfonate and anhydrous sodium sulfate are sent to a dryer (drying temperature 80℃, drying time 2 hours), and after being dried to a moisture content ≤1%, they are stored in a storage silo with stirring (stirring speed 50r / min to prevent agglomeration).

[0050] 2. Segmented Mixing Stage Preparation of the core cementitious matrix: Start the biaxial paddle mixer (effective volume 5m³, paddle speed adjustable by frequency conversion), first add 42.5 grade ordinary Portland cement (measured according to the formula ratio, error ≤ ±0.5%) to the mixer through the metering screw conveyor, and start stirring (speed 60r / min); after 3 minutes, add metakaolin (metering error ≤ ±0.5%), and continue stirring for 5 minutes; then add activated granulated blast furnace slag powder (metering error ≤ ±0.5%), and stir for 7 minutes, for a total stirring time of 15 minutes, to form a uniform core cementitious matrix; during the mixing process, take samples every 5 minutes through the sampling port on the side wall of the mixer, and use a laser particle size analyzer to detect the particle size distribution of the mixture, ensuring that the D50 fluctuation range is ≤ ±2μm. If it exceeds the range, adjust the stirring speed (±5r / min).

[0051] Mixing of anti-erosion components: Keep the mixer speed constant at 60 r / min, add calcined dolomite powder (metering error ≤ ±0.5%) through a metering screw conveyor, and stir for 4 minutes; then add hydrated calcium silicate micro powder (metering error ≤ ±0.1%, delivered by a micro metering pump), and stir for 3 minutes; finally add nano silica (metering error ≤ ±0.1%, delivered by pneumatic conveying at a pressure of 0.2 MPa), and stir for 5 minutes, for a total stirring time of 12 minutes; during the mixing process, use an online moisture meter to detect the moisture content of the mixture, ensuring that the moisture content is ≤ 1.5%. If the moisture content is too high, turn on the hot air device of the mixer (hot air temperature 60℃, wind speed 0.3 m / s) to reduce the moisture to the acceptable range.

[0052] Mixing the anti-deliquescence system: Reduce the mixer speed to 40 r / min, add modified bentonite (metering error ≤ ±0.5%) via a metering screw conveyor, and stir for 6 minutes; then add plasma-treated polyetheretherketone short fibers (metering error ≤ ±0.1%, fibers evenly spread on the belt to prevent agglomeration) via a belt conveyor, and stir for 8 minutes; then add silane coupling agent KH-550 (metering error ≤ ±0.05%, pump speed 5 mL / min) via a metering pump, and stir for 6 minutes, for a total stirring time of 20 minutes; during the mixing process, observe the fiber dispersion using a high-speed camera. If fiber agglomeration occurs, add 0.1% (relative to fiber mass) of dispersant (polyethylene glycol 400) and extend the stirring time by 3 minutes.

[0053] Mixing of the auxiliary modified system: Increase the mixer speed to 80 r / min, add triethanolamine through a metering pump (metering error ≤ ±0.01%, pump speed 2 mL / min), and stir for 2 minutes; then add calcium lignosulfonate through a metering screw conveyor (metering error ≤ ±0.05%), and stir for 3 minutes; finally add anhydrous sodium sulfate (metering error ≤ ±0.05%), and stir for 3 minutes, for a total stirring time of 8 minutes; after mixing, stop the machine and take samples. Use a cement mortar consistency meter to test the consistency of the mixture (standard consistency water consumption fluctuation range ≤ ±0.5%), and use an X-ray diffractometer to test the content of the main components (deviation from the formula design value ≤ ±2%). Only after passing the test can the next step be carried out.

[0054] 3. Quality Inspection and Adjustment Stage Particle size distribution test: Take 100g of sample from the mixer outlet and use a laser particle size analyzer (test range 0.1~1000μm) to test the particle size distribution. The requirements are D10≥2μm, D50=10~15μm, D90≤30μm. If D50 is outside the range, return to the ball mill for re-grinding and adjustment.

[0055] Activity index test: Prepare mortar specimens according to GB / T18046-2017 standard (curing material: standard sand: water = 1:3:0.5), test compressive strength after standard curing for 28 days, calculate the activity index (relative to the reference cement) ≥90%. If the activity index is insufficient, increase the amount of metakaolin (add 1 part metakaolin for every 5% less) and remix.

[0056] Preliminary testing of chloride ion penetration resistance: The mixed solidified material was mixed with simulated coastal soft soil (chloride ion mass fraction 1.0%) at a mass ratio of 1:5 to prepare Φ50mm×100mm specimens. After standard curing for 28 days, the chloride ion diffusion coefficient was tested using the rapid chloride ion migration method (RCM method), requiring ≤1.0×10⁻⁶. -12 m 2 / s, if the diffusion coefficient exceeds the standard, increase the amount of nano-silica doping (for every 0.2×10⁻⁶ exceeding the standard). -12 m 2 Add 0.2 parts of nano-silica per second and remix.

[0057] 4. Sealed storage stage Packaging process: Qualified composite curing materials are fed into an automatic packaging machine via a closed conveyor belt (packaging speed 50 bags / minute). They are packaged in three-layer composite bags (inner layer is polyethylene film, middle layer is polypropylene woven fabric, and outer layer is waterproof coated fabric). Each bag has a net weight of 25kg (error ≤ ±0.2kg). During the packaging process, silica gel desiccant (50g per bag, moisture content ≤ 5%) is added to the bag to ensure that the material is not exposed to moisture during storage.

[0058] Storage environment control: Packaged products are placed in a temperature and humidity controlled warehouse. The warehouse temperature is controlled at 5~30℃ (using an air conditioning system, with temperature fluctuation ≤±2℃), and the relative humidity is ≤60% (using a dehumidifier, with humidity fluctuation ≤±5%). Shelves are set up in the warehouse, with the product height ≥10cm from the ground and distance from the wall ≥50cm, and the number of stacking layers ≤10 to prevent the bottom products from being compressed and clumping. Temperature and humidity recorders are installed in the warehouse to record data once an hour to ensure a stable storage environment.

[0059] Storage period management: The production date and storage period (not exceeding 3 months) are marked on the product label, and the first-in, first-out (FIFO) principle is adopted for outbound delivery; every 15 days, the products in the warehouse are sampled and tested (the test items include moisture content, particle size distribution, and activity index). If the moisture content exceeds 2% or the activity index drops by more than 10%, the batch of products is stopped from leaving the warehouse and re-activated (0.5 parts of anhydrous sodium sulfate are added to the mixer and stirred for 5 minutes) and then tested again. Only products that pass the test can be used.

[0060] This embodiment also provides a method for solidifying coastal soft soil using the above-mentioned composite solidification material, employing a solidification process of "pretreatment-layered mixing-curing and strengthening," with the specific steps as follows: 1) Soft soil pretreatment: Remove surface impurities (stones, plant roots, etc.) from the coastal soft soil. Use a tracked crusher to crush the soft soil to a particle size of ≤20mm. Feed it into a forced mixer, add an appropriate amount of water to adjust the moisture content of the soft soil to 45%~55% (5~10 percentage points lower than the natural moisture content), and mix for 10 minutes to obtain homogenized soft soil. For homogenized soft soil, if the chloride ion mass fraction is >1.0%, add 2%~3% of its mass of zeolite powder to the soft soil, stir for 8 minutes to preliminarily adsorb some free chloride ions, and let stand for 30 minutes. 2) Layered mixing and curing: Weigh out 18% to 22% of the composite solidification material according to the mass of the soft soil, and add it to the pretreated soft soil in three parts: first, add 50% of the solidification material and stir for 12 minutes; second, add 30% of the solidification material and stir for 10 minutes; third, add 20% of the solidification material and stir for 8 minutes. The total stirring time should be ≥30 minutes to ensure that the solidification material and the soft soil are evenly mixed to form a solidified soil slurry. An immersion vibrator was used to compact the solidified soil slurry at a frequency of 50 Hz and a compaction time of 3 minutes per cubic meter of slurry. During the compaction process, the insertion depth of the vibrator was controlled to be 30-50 cm and the spacing between insertion points was 20 cm to ensure that the slurry was compacted and to remove internal air bubbles. If the curing depth exceeds 1.5m, a layered pouring method shall be adopted, with each layer being 50cm thick. After the lower layer is poured, the upper layer shall be poured after an interval of 2 hours to avoid weak bonding surfaces between layers. 3) Enhanced maintenance: After the pouring is completed, immediately cover the solidified soil surface with a polyethylene film to retain moisture. The overlap width of the film should be ≥10cm, and the edges should be compacted with heavy objects to prevent moisture evaporation and external moisture intrusion. During the initial curing period (1-7 days): the ambient temperature should be controlled at 15-25℃. If the ambient temperature is below 10℃, use an electric heating blanket for insulation to ensure that the curing reaction proceeds normally. Check the integrity of the film regularly every day and repair it in time if any damage occurs. Keep the surface of the cured soil moist but without water accumulation. Mid-curing stage (8-21 days): Remove the film and use spray curing, spraying twice a day (9 am and 4 pm), with each spray amount being 0.5% of the mass of the solidified soil, to avoid excessive moisture leading to deliquescence; Post-curing stage (22-28 days): Natural curing, regularly check the moisture content of the solidified soil and keep it between 15% and 20%. If the moisture content is lower than 15%, spray to bring it up to the specified range. Post-curing protection: After curing, apply a penetrating fluorocarbon coating to the surface of the solidified soil. The coating thickness is 30~50μm. Apply two coats, with a 4-hour interval between the first and second coats, to further enhance resistance to chloride salt corrosion and deliquescence.

[0061] Example 2 Core cementitious system: 75 parts (38 parts of 42.5 grade ordinary Portland cement, 14 parts of metakaolin, and 23 parts of S95 grade granulated blast furnace slag) Anti-erosion system: 15 parts (9 parts calcined dolomite powder, 4 parts hydrated calcium silicate micro powder, 2 parts nano silica) Anti-deliquescence system: 8 parts (6 parts modified bentonite, 1.0 part polyetheretherketone short fiber, 4 parts silane coupling agent KH-5500) Auxiliary modification system: 0.9 parts (0.1 parts triethanolamine, 0.25 parts calcium lignosulfonate, 0.55 parts anhydrous sodium sulfate) Total mass: 98.9 parts Example 3 Core cementitious system: 82 parts (42 parts of 42.5 grade ordinary Portland cement, 16 parts of metakaolin, and 24 parts of S95 grade granulated blast furnace slag) Anti-erosion system: 18 parts (11 parts calcined dolomite powder, 4.5 parts hydrated calcium silicate micro powder, 2.5 parts nano silica) Anti-deliquescence system: 9.5 parts (7 parts modified bentonite, 1.1 parts polyetheretherketone short fiber, 0.45 parts silane coupling agent KH-5500) Auxiliary modification system: 1.1 parts (triethanolamine 0.11 parts, calcium lignosulfonate 0.28 parts, anhydrous sodium sulfate 0.71 parts) Total mass parts: 110.6 parts Example 4 Core cementitious system: 88 parts (45 parts of 42.5 grade ordinary Portland cement, 18 parts of metakaolin, and 25 parts of S95 grade granulated blast furnace slag) Anti-erosion system: 19.5 parts (12 parts calcined dolomite powder, 5 parts hydrated calcium silicate micro powder, 2.5 parts nano silica) Anti-deliquescence system: 10.7 parts (8 parts modified bentonite, 1.2 parts polyetheretherketone short fiber, 0.5 parts silane coupling agent KH-550) Auxiliary modification system: 1.22 parts (triethanolamine 0.12 parts, calcium lignosulfonate 0.3 parts, anhydrous sodium sulfate 0.8 parts) Total weight: 119.42 portions Experimental results Examples 1-5 all employed the same preparation process and curing method, using coastal soft soil with a chloride ion mass fraction of 0.8%, a natural moisture content of 65%, and a porosity of 1.6 as the substrate. The curing material was mixed with the soft soil at a mass ratio of 20%. After 28 days of standard curing, the core performance was tested, and the results are shown in Table 1 below. Table 1

[0062] Note: Grade 1 for deliquescence resistance is excellent (deliquescence ≤ 5%), and Grade 2 is good (deliquescence 5%~10%); chloride ion diffusion coefficient ≤ 1.0 × 10⁻⁶. -12 m 2 / s is considered acceptable; the lower the value, the better the corrosion resistance.

[0063] Example 5 This embodiment provides a deliquescence-resistant composite solidification material for coastal soft soil and its preparation and application method. Unlike Embodiment 1, the formulations of each system in this embodiment are as follows, with a total mass fraction of 100 parts: Core cementitious system: 78 parts. Specifically: 35 parts of 42.5 grade ordinary Portland cement, 18 parts of metakaolin, and 25 parts of S95 grade granulated blast furnace slag.

[0064] Anti-erosion system: 15.5 parts. To maintain the proportion coordination with the core cementing system, the following adjustments were made after calculation: calcined dolomite powder 9.5 parts, hydrated calcium silicate micro powder 4.2 parts, and nano silica 1.8 parts.

[0065] Anti-deliquescence system: 8.1 parts. Specifically: 6.5 parts modified bentonite, 1.0 part polyetheretherketone short fiber, and 0.6 parts silane coupling agent KH-550.

[0066] Auxiliary modification system: 1.22 parts. Specifically: 0.12 parts triethanolamine, 0.3 parts calcium lignosulfonate, and 0.8 parts anhydrous sodium sulfate.

[0067] The preparation method, curing method, and raw material processing technology are the same as in Example 1. Tested under the same conditions, its main performance indicators are expected to be between those of Example 1 and Example 2, as detailed below: 28-day compressive strength: ~385 kPa; Chloride ion diffusion coefficient: ~0.85 × 10⁻⁶ - ¹² m² / s; Deliquescence resistance rating: Grade 1; Cure density: ~1.90 g / cm³; 28-day shear strength: ~98 kPa; Example 6 This embodiment provides a deliquescence-resistant composite solidification material for coastal soft soil and its preparation and application method. Unlike Embodiment 1, the proportions of each system in this embodiment are as follows, with a total mass fraction of 112 parts: Core cementitious system: 77 parts. Specifically: 45 parts of 42.5 grade ordinary Portland cement, 12 parts of metakaolin, and 20 parts of S95 grade granulated blast furnace slag.

[0068] Anti-erosion system: 19.0 parts. Specifically: 11.5 parts calcined dolomite powder, 4.8 parts hydrated calcium silicate micro powder, and 2.7 parts nano silica.

[0069] Anti-deliquescence system: 9.5 parts. Specifically: 7.2 parts modified bentonite, 1.1 parts polyetheretherketone short fiber, and 0.5 parts silane coupling agent KH-550.

[0070] Auxiliary modification system: 0.78 parts. Specifically: 0.08 parts triethanolamine, 0.2 parts calcium lignosulfonate, and 0.5 parts anhydrous sodium sulfate.

[0071] The preparation method, curing method, and raw material processing technology are the same as in Example 1. Tested under the same conditions, its main performance indicators are expected to be between those of Example 2 and Example 3, as detailed below: 28-day compressive strength: ~450 kPa; Chloride ion diffusion coefficient: ~0.65 × 10⁻⁶ - ¹² m² / s; Deliquescence resistance rating: Grade 1; Cure density: ~1.99 g / cm³; 28-day shear strength: ~118 kPa.

[0072] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A composite solidification material for coastal soft soil resistant to deliquescence, characterized in that, By weight, it includes: 6.1~10.7 parts of anti-deliquescence system, 67~88 parts of core cementing system, 12.5~19.5 parts of anti-erosion system, and 0.78~1.22 parts of auxiliary modification system; The anti-deliquescence system comprises 5-8 parts modified bentonite, 0.8-1.2 parts polymer fiber, and 0.3-0.5 parts silane coupling agent; the anti-erosion system comprises 8-12 parts calcined dolomite powder, 3-5 parts hydrated calcium silicate micro powder, and 1.5-2.5 parts nano silica.

2. The anti-deliquescence composite solidification material for coastal soft soil according to claim 1, characterized in that, The modified bentonite is obtained by modifying calcium-based bentonite with cationic surfactants.

3. The anti-deliquescence composite solidification material for coastal soft soil according to claim 1, characterized in that, The polymer fiber is a short polyetheretherketone fiber.

4. The anti-deliquescence composite solidification material for coastal soft soil according to claim 1, characterized in that, The core cementitious system, by mass parts, includes 35-45 parts silicate cement, 12-18 parts metakaolin, and 20-25 parts granulated blast furnace slag.

5. The anti-deliquescence composite solidification material for coastal soft soil according to claim 1, characterized in that, The auxiliary modification system, by mass parts, includes 0.08-0.12 parts of triethanolamine, 0.2-0.3 parts of calcium lignosulfonate, and 0.5-0.8 parts of anhydrous sodium sulfate.

6. A method for preparing a coastal soft soil anti-deliquor composite solidification material according to any one of claims 1-5, characterized in that, Includes the following steps: 1) Pretreatment of the core cementing system, anti-erosion system, anti-deliquescence system, and auxiliary modification system; 2) Mix the core cementing system, anti-erosion system, anti-deliquescence system and auxiliary modification system in sequence. First mix the core cementing system, then add the anti-erosion system, then add the anti-deliquescence system, and finally add the auxiliary modification system. Mix evenly to obtain the anti-deliquescence composite solidification material for coastal soft soil.

7. A method for solidifying coastal soft soil using the anti-deliquescence composite solidification material for coastal soft soil as described in any one of claims 1-5, characterized in that, Includes the following steps: a) Remove impurities from the surface layer of coastal soft soil, break the soft soil to a particle size ≤20mm, and adjust the moisture content to 45%-55%; b) Add the composite curing material to the coastal soft soil treated in step a) in three portions, at a weight of 18%-22% of the coastal soft soil mass. Stir and vibrate after each addition to obtain a mixture. Then pour the mixture into the construction area. c) After pouring, cover with a film to retain moisture, carry out initial, intermediate and late curing, and apply a protective coating after curing.

8. The method according to claim 7, characterized in that, In step a), if the chloride ion mass fraction of the coastal soft soil is >1.0%, add 2%-3% of the mass of zeolite powder to the coastal soft soil for preliminary adsorption, and let it stand for 30 minutes.

9. The method according to claim 7, characterized in that, In step b), the composite curing material is added in three parts: the first part is 50% of the mass of the coastal soft soil, and the mixture is stirred for 12 minutes; the second part is 30% of the mass of the coastal soft soil, and the mixture is stirred for 10 minutes; the third part is 20% of the mass of the coastal soft soil, and the mixture is stirred for 8 minutes.

10. The method according to claim 7, characterized in that, In step c), during the initial curing period of 1-7 days, cover with a film and maintain an ambient temperature of 15-25℃; during the intermediate curing period of 8-21 days, use spray curing, spraying twice a day; during the later curing period of 22-28 days, allow for natural curing; after curing, apply a penetrating fluorocarbon coating with a thickness of 30μm-50μm.

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