Cement-based material resistant to organic acid corrosion and method for its production

Abstract

This application relates to the field of cement materials technology, and particularly to a cement-based material resistant to organic acid corrosion and its preparation method. According to parts by weight, the cement-based material resistant to organic acid corrosion comprises 90-100 parts cement, 40-60 parts mineral admixtures, 180-220 parts river sand, 15-25 parts composite modifier, 8-12 parts polymer modifier, 6-10 parts functional additives, and 30-35 parts water. The preparation method of the composite modifier includes the following steps: drying and pulverizing the filler, mixing it with a colloidal encapsulating agent at high speed for 15-20 minutes, adding a chelation inhibitor and povidone, heating to 55-60°C, stirring at that temperature for 20-25 minutes, and cooling to room temperature to obtain the composite modifier. The polymer modifier comprises acrylic emulsion and resin, wherein the mass ratio of the acrylic emulsion to the resin is (3-4):1. This application addresses the problem of weak organic acid corrosion resistance in traditional cement-based materials by providing a cement-based material resistant to organic acid corrosion and its preparation method.

Description

Technical Field

[0001] This application relates to the field of cement materials technology, and in particular to a cement-based material resistant to organic acid corrosion and its preparation method. Background Technology

[0002] Grouting materials are widely used in prefabricated building sleeve grouting, underground structure repair, and industrial equipment foundation anchoring. Their core functions include filling cracks, reinforcing soil and rock, preventing seepage, and providing long-term structural stability. However, in many practical engineering environments, grouting structures are at risk of long-term exposure to corrosive environments containing organic acids, such as wastewater in wastewater treatment facilities, oxalic acid solutions used in industrial rust removal and cleaning, and short-chain fatty acids like acetic acid and propionic acid in sludge; lactic acid, acetic acid, and citric acid in fermentation tanks and storage tanks in agriculture and food industries; areas in chemical production environments involving the production, storage, or leakage of organic acids; acetic acid and butyric acid produced by microbial metabolism in landfills and anaerobic digesters in biodegradation environments; and natural humic acids and fulvic acid in certain groundwater or soil in geological environments. The erosion mechanisms of these organic acids on cement-based grouting materials differ significantly from those of inorganic acids. Long-term exposure of grouting materials to complex and harsh environments such as alternating wet and dry conditions and organic acid corrosion can lead to material strength degradation, volume expansion, bond failure, and even structural disintegration, causing irreversible safety problems. Summary of the Invention

[0003] This application provides a cement-based material resistant to organic acid corrosion and its preparation method, in order to solve the problem of weak resistance to organic acid corrosion in traditional cement-based materials in related technologies.

[0004] In a first aspect, a cement-based material resistant to organic acid corrosion is provided, comprising, by weight parts: 90-100 parts cement, 40-60 parts mineral admixtures, 180-220 parts river sand, 15-25 parts composite modifier, 8-12 parts polymer modifier, 6-10 parts functional additives, and 30-35 parts water. The mineral admixture includes silica fume; The preparation method of the composite modifier includes the following steps: After the filler is dried and pulverized, it is mixed with the colloidal encapsulating agent at high speed for 15-20 minutes, then the chelation inhibitor and povidone are added, the temperature is raised to 55-60℃, the mixture is kept warm and stirred for 20-25 minutes, and then cooled to room temperature to obtain the composite modifier. The mass ratio of the filler, colloidal encapsulating agent, chelation inhibitor, and povidone is 2:(3~5):(2~3):(1~2), the colloidal encapsulating agent comprises cyclodextrin and hydroxyethyl cellulose in a mass ratio of 1:(0.3~0.5), and the chelation inhibitor is selected from magnesium fluorosilicate or sodium fluorosilicate. The polymer modifier comprises an acrylic emulsion and a resin, wherein the mass ratio of the acrylic emulsion to the resin is (3~4):1.

[0005] Preferably, the mineral admixture further includes fly ash, wherein the mass ratio of fly ash to silica fume is (0.6~0.8):1.

[0006] Preferably, the filler comprises at least one of sepiolite and diatomaceous earth.

[0007] Preferably, the filler comprises sepiolite and diatomaceous earth in a mass ratio of 1:1.

[0008] Preferably, in the polymer modifier, the resin is selected as a low-viscosity bisphenol A epoxy resin, and the preparation method of the polymer modifier includes: At room temperature and under stirring conditions, low-viscosity bisphenol A epoxy resin was added dropwise to acrylic emulsion. After the addition was complete, the temperature was raised to 45~50℃ and stirred for 20~30 minutes to obtain a polymer modifier.

[0009] Preferably, the stirring conditions are 250~300 r / min.

[0010] Preferably, the functional additives include a water-reducing agent, a swelling agent, and an antifoaming agent in a mass ratio of (3~5):(2~3):(0.5~1); The water-reducing agent is selected from polycarboxylate-based high-performance water-reducing agents, the expanding agent is selected from EP-2 plastic expanding agent, and the defoamer is selected from tributyl phosphate.

[0011] Preferably, the conditions for drying and pulverizing the filler are as follows: the filler is placed in an oven and dried at 100~105℃ for 1~2 hours, then pulverized through a 200-mesh sieve to complete the drying and pulverizing process.

[0012] Secondly, a method for preparing a cement-based material resistant to organic acid corrosion is provided, which is used to prepare the cement-based material resistant to organic acid corrosion as described above, and includes the following steps: S1. Add cement, mineral admixtures, and river sand to the mixer and dry mix for 5-6 minutes. After adding the composite modifier, continue mixing for 8-10 minutes. S2. Mix water and functional additives, and add polymer modifier under stirring conditions. Stir for 8-10 minutes to obtain a mixture. S3. Under stirring conditions, the mixture is slowly added to the material obtained in S1 to obtain a mixture. S4. The mixture is placed into a mold coated with a release agent, vibrated and molded, and then cured at 18~22℃ for 22~24h before demolding. The sample is then covered with geotextile and wet-cured for 6~7 days before being taken out and naturally cured for 20~21 days until the test age.

[0013] Preferably, in step S3, the stirring conditions are: first stirring at 250~300 r / min for 2~3 min, and then stirring at 550~600 r / min for 3~5 min.

[0014] The beneficial effects of the technical solution provided in this application include: This application provides a cement-based material resistant to organic acid corrosion and its preparation method. Mineral admixtures continuously consume calcium hydroxide generated during the hydration of silicate cement, reducing the proportion of easily corroded high-calcium products and generating CSH gel. Simultaneously, this refines the internal pores of the cement-based material, optimizes the pore structure, and reduces the capillary penetration channels of organic acid solutions, thereby reducing the basis for organic acid decalcification corrosion reactions. The colloidal encapsulating agent in the composite modifier strengthens the interfacial bonding between the organic phase and the inorganic cement matrix, improving the weak organic-inorganic interface bonding and the defects of corrosive media seeping along the interface. The chelation inhibitor reacts with hydration products to generate chemically stable fluorosilicate inert products, effectively inhibiting the chelation decalcification effect of organic acids and weakening the erosion of weak acid buffers. Povidone further optimizes the system's dispersibility, assists in promoting cement hydration, and reduces internal residual closed pores. A polymer modifier is prepared by compounding acrylic emulsion and resin, improving the defects of traditional organic polymers such as easy swelling, easy hydrolysis, hindering cement hydration, and residual pores. Therefore, it can solve the problem of weak organic acid corrosion resistance in traditional cement-based materials in related technologies. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A flowchart illustrating the method for preparing cement-based materials resistant to organic acid corrosion provided in this application; Figure 2 The images show the effects of the organic acid-resistant cementitious material provided in Example 1 of this application after acetic acid corrosion for 60d, 90d, 120d, and 180d. Figure 2 (a) in the text represents corrosion after 60 days. Figure 2 (b) in the image represents corrosion 90d. Figure 2 (c) represents corrosion 120d. Figure 2 (d) in the figure represents corrosion 180d; Figure 3 The images show the effects of organic acid-resistant cementitious material provided in Comparative Example 1 of this application after acetic acid corrosion for 60d, 90d, 120d, and 180d. Figure 3(a) in the text represents corrosion after 60 days. Figure 3 (b) in the image represents corrosion 90d. Figure 3 (c) represents corrosion 120d. Figure 3 (d) in the figure represents corrosion 180d; Figure 4 The XRD pattern of Comparative Example 1 provided for this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] See Figures 1-4 As shown, this application provides a cement-based material resistant to organic acid corrosion and its preparation method.

[0019] In the following examples and comparative examples, unless otherwise specified, all cement used is silicate cement, specifically P·II52.5R silicate cement of the Jin Yang brand.

[0020] In the following examples and comparative examples, the acrylic emulsion used was an aqueous acrylic emulsion with a solid content of 35% and a viscosity of 1200~1600 CPS; the defoamer used was tributyl phosphate with a content greater than 98.5%; the silica fume used was silica fume produced by Gansu Sanyuan Silicon Materials Co., Ltd.; the fly ash used was fly ash produced by Shijiazhuang Zhengyu New Materials Technology Co., Ltd.; the river sand used had a particle size of 0.16~4.75mm, a fineness of 2.9, and a mud content of 2.25%; and the sepiolite was 200 mesh ultrafine powder with a SiO2 content ≥55% and a specific surface area ≥120 m². 2 / g; Diatomaceous earth is 200 mesh diatomaceous earth powder, SiO2 content ≥85%, porosity 65%~75%, average pore size 20~50nm; Cyclodextrin is industrial grade β-cyclodextrin; Hydroxyethyl cellulose molecular weight 20000Da, degree of substitution DS=1.9; Magnesium fluorosilicate / Sodium fluorosilicate are both industrial premium grade, effective content ≥98%; Povidone type is PVP K30, average molecular weight: 45000 g / mol; Low viscosity bisphenol A epoxy resin type is E51 (bisphenol A type).

[0021] The main performance indicators of acrylic emulsions are shown in Table 1.

[0022] Table 1 Main performance indicators of acrylic emulsion Example 1 The method for preparing cement-based materials resistant to organic acid corrosion provided in this embodiment includes the following steps: S101. Add 190g of silicate cement, 100g of mineral admixture, and 400g of river sand to the mixer, dry mix at 150r / min for 5min, add 40g of composite modifier, and continue mixing at 180r / min for 8min. The mineral admixture is a mixture of fly ash and silica fume with a mass ratio of 0.8:1; The preparation method of the composite modifier is as follows: Place 10g sepiolite and 10g diatomaceous earth in an oven and dry at 105℃ for 2 hours. Then, pulverize them through a 200-mesh sieve to complete the drying and pulverization. Mix them with 40g colloidal coating agent at a high speed of 1000r / min for 15 minutes. Add 20g magnesium fluorosilicate and 10g povidone, heat to 55℃, keep warm and stir for 20 minutes, and cool to room temperature to obtain the composite modifier.

[0023] The 40g colloidal encapsulating agent was taken from a mixture of 30g cyclodextrin and 12g hydroxyethyl cellulose.

[0024] S102. Mix 16g of functional additive with 65g of water, and add 20g of polymer modifier under stirring at 500r / min. Stir for 10min to obtain a mixture. The functional additives include a polycarboxylate-based high-performance water-reducing agent, EP-2 plastic expansion agent, and tributyl phosphate in a mass ratio of 3:2:0.5. The preparation method of the polymer modifier is as follows: At room temperature and with stirring at 300 r / min, 5 g of low-viscosity bisphenol A epoxy resin (epoxy value 0.52) was added dropwise to 15 g of acrylic emulsion (solid content 35%). After the addition was complete, the temperature was raised to 45°C and stirred for 30 min to obtain the polymer modifier.

[0025] S103. Under stirring conditions of 300 r / min, the mixture prepared in S102 is slowly added to the material prepared in S101, stirred for 2 min, and then stirred at 600 r / min for 3 min to obtain the mixture. S104. The mixture is placed into a mold coated with a release agent, vibrated and molded, and then cured at 20±2℃ for 24 hours before demolding. The sample is then covered with geotextile and wet-cured for 7 days before being taken out and naturally cured for 21 days until the test age.

[0026] Example 2 The difference between this embodiment and Embodiment 1 is that fly ash is not added, and the mineral admixture is replaced with an equal amount of silica fume; and the filler in the composite modifier is replaced with an equal amount of sepiolite.

[0027] Example 3 The method for preparing cement-based materials resistant to organic acid corrosion provided in this embodiment includes the following steps: S301. Add 180g of silicate cement, 80g of mineral admixture, and 360g of river sand to the mixer and dry mix at 120r / min for 5min. After adding 30g of composite modifier, continue mixing at 150r / min for 8min. The mineral admixture is a mixture of fly ash and silica fume with a mass ratio of 0.6:1; The preparation method of the composite modifier is as follows: Place 5g sepiolite and 5g diatomaceous earth in an oven and dry at 10℃ for 2 hours. Then, pulverize them through a 200-mesh sieve to complete the drying and pulverization. Mix them with 15g colloidal encapsulating agent at a high speed of 800r / min for 15 minutes. Add 15g sodium fluorosilicate and 5g povidone, heat to 60℃, keep warm and stir for 20 minutes, and cool to room temperature to obtain the composite modifier.

[0028] The colloidal encapsulating agent is a mixture of 10g cyclodextrin and 5g hydroxyethyl cellulose.

[0029] S302. Mix 12g of functional additive with 60g of water, and add 16g of polymer modifier under stirring at 500r / min. Stir for 8min to obtain a mixture. The functional additives include polycarboxylate-based high-performance water-reducing agent, EP-2 plastic expansion agent, and tributyl phosphate in a mass ratio of 5:3:1. The preparation method of the polymer modifier is as follows: At room temperature and with stirring at 250 r / min, 3.5 g of low viscosity bisphenol A epoxy resin (epoxy value 0.52) was added dropwise to 14 g of acrylic emulsion (solid content 35%). After the addition was complete, the temperature was raised to 50 °C and stirred for 20 min to obtain the polymer modifier.

[0030] S303. Under stirring conditions of 250 r / min, the mixture prepared in S302 is slowly added to the material prepared in S301, stirred for 2 min, and then stirred at 550 r / min for 3 min to obtain the mixture. S304. The mixture is placed into a mold coated with a release agent, vibrated and molded, and then cured at 20±2℃ for 22 hours before demolding. The sample is then covered with geotextile and wet-cured for 6 days before being taken out and naturally cured for 20 days until the test age.

[0031] Example 4 The method for preparing cement-based materials resistant to organic acid corrosion provided in this embodiment includes the following steps: S401. Add 200g of silicate cement, 120g of mineral admixture, and 440g of river sand to the mixer and dry mix at 150r / min for 6min. After adding 50g of composite modifier, continue mixing at 180r / min for 10min. The mineral admixture is a mixture of fly ash and silica fume with a mass ratio of 0.8:1; The preparation method of the composite modifier is as follows: Place 10g of diatomaceous earth in an oven and dry it at 105℃ for 1 hour. Then, pulverize it through a 200-mesh sieve to complete the drying and pulverization. Mix it with 25g of colloidal encapsulating agent at a high speed of 1000r / min for 20 minutes. Then, add 10g of magnesium fluorosilicate and 10g of povidone. Heat the mixture to 55℃, keep it warm and stir for 20 minutes. After cooling to room temperature, the composite modifier is obtained.

[0032] The 25g colloidal encapsulating agent mentioned above is taken from a mixture of 20g cyclodextrin and 6g hydroxyethyl cellulose.

[0033] S402. Mix 20g of functional additive with 70g of water, and add 24g of polymer modifier under stirring at 500r / min. Stir for 10min to obtain a mixture. The functional additives include polycarboxylate-based high-performance water-reducing agent, EP-2 plastic expansion agent, and tributyl phosphate in a mass ratio of 4:2:1. The preparation method of the polymer modifier is as follows: At room temperature and with stirring at 300 r / min, 6 g of low-viscosity bisphenol A epoxy resin (epoxy value 0.52) was added dropwise to 18 g of acrylic emulsion (solid content 35%). After the addition was complete, the temperature was raised to 45°C and stirred for 30 min to obtain the polymer modifier.

[0034] S403. Under stirring conditions of 300 r / min, the mixture prepared in S402 is slowly added to the material prepared in S401, stirred for 3 min, and then stirred at 600 r / min for 5 min to obtain the mixture. S404. The mixture is placed into a mold coated with a release agent, vibrated and molded, and then cured at 20±2℃ for 24 hours before demolding. The sample is then covered with geotextile and wet-cured for 7 days before being taken out and naturally cured for 21 days until the test age.

[0035] Comparative Example 1 The difference from Example 1 is that no composite modifier is added in this comparative example.

[0036] Comparative Example 2 The difference from Example 1 is that no polymer modifier was added in this comparative example.

[0037] Comparative Example 3 The difference from Example 1 is that no composite modifier or polymer modifier is added in this comparative example.

[0038] Comparative Example 4 The difference from Example 1 is that in this comparative example, the composite modifier is replaced with an equal amount of sepiolite.

[0039] The cement-based materials resistant to organic acid corrosion (hereinafter referred to as "cement-based materials") prepared in the examples and comparative examples were tested.

[0040] Mechanical property testing: Referring to GB / T 17671-2021 "Test Method for Strength of Cement Mortar", a prism specimen of 40mm×40mm×160mm was prepared. The side of the specimen was placed on the support cylinder of the flexural strength testing machine, with the long axis of the specimen perpendicular to the support cylinder. The load was uniformly applied vertically to the opposite side of the prism at a rate of 50N / s through the loading cylinder until it broke.

[0041] Keep both halves of the prism moist until the compression test.

[0042] Calculate flexural strength: In the formula, R f Flexural strength (MPa); F f The load (N) applied to the middle of the prism when it breaks. L is the distance between the supporting cylinders (mm); b is the side length (mm) of the square cross-section of the prism.

[0043] After the flexural strength test, two halves of the specimen were removed for the compressive strength test; a microcomputer-controlled electro-hydraulic servo pressure testing machine was used, with a loading rate of 2.4 kN / s and a pressure area of ​​1600 mm². 2 Calculate the compressive strength: In the formula: R c Compressive strength (MPa); F c The maximum load (N) at failure; A is the area under pressure (mm²) 2 ).

[0044] The results are shown in Table 2.

[0045] Table 2 Mechanical properties of the embodiments and comparative examples In the cement-based materials prepared in the examples, the composite modifier effectively fills the pores in the cement. The colloidal thickening effect of the colloidal encapsulator improves the agglomeration of particles, reduces internal defects, and significantly improves density. The polymer modifier forms an interpenetrating network, which acts as a bridge in the cement hydration products, alleviates stress concentration, and improves flexural strength. The secondary pozzolanic reaction of the mineral admixture consumes Ca(OH)2 to generate dense low-calcium CSH gel, which synergistically improves compressive and flexural strength.

[0046] In Example 2, only silica fume was used as the mineral admixture, which reduced the total amount of secondary hydration products. The filler was a single sepiolite, and the pore filling efficiency was lower than that of Example 1. Its flexural strength and compressive strength were also slightly lower than those of Example 1. Compared with Example 1, Examples 3 and 4 adjusted the mass fraction of each material, but still maintained a high density and interfacial bonding force, and the mechanical properties were close to those of Example 1.

[0047] In the comparative examples, Comparative Example 1 lacked a composite modifier compared to Example 1, resulting in a lack of pore filling and interface reinforcement, and a lower density of cement stone, but its overall performance remained at a high level. Comparative Example 2 lacked a polymer modifier, resulting in a significant decrease in flexural strength, and its compressive strength was also reduced due to insufficient density. Comparative Example 3 lacked both a composite modifier and a polymer modifier, resulting in a loose structure of hydration products and the worst mechanical properties. Comparative Example 4 used a single sepiolite instead of a composite modifier, which only had a simple filling effect and lacked synergistic effects such as colloidal encapsulation and chelation inhibition, resulting in weak interfacial bonding and insufficient density.

[0048] Organic acid corrosion resistance test: The sample was immersed in a 5 wt% acetic acid solution for 60 days. Its resistance to organic acid corrosion was compared and studied by periodically testing compressive strength, flexural strength, rate of change of mass, and rate of change of elastic modulus, combined with XRD and SEM-EDS microscopic analysis.

[0049] Weigh the initial mass (m0), use a dynamic elasticity tester to test the initial dynamic elastic modulus (P0), and test the initial compressive strength (f0). After soaking, take out the test block, rinse the surface with clean water, and dry it to constant weight (105℃, 24h). Weigh the mass after corrosion (m1), and test the dynamic elastic modulus (P1) and compressive strength (f1) after corrosion.

[0050] Quality loss rate (%) = [(m0-m1) / m0] × 100% Relative dynamic elastic modulus loss rate (%) = [(P0-P1) / P0] × 100% Compressive strength and acid corrosion resistance coefficient (%) = (f1 / f0) × 100% The results are shown in Table 3.

[0051] Table 3. Resistance to organic acid corrosion in the examples and comparative examples In this embodiment, the low-viscosity bisphenol A epoxy resin effectively enhances the hydrolysis and swelling resistance of the acrylic emulsion, does not hinder cement hydration, has few internal pores, and makes it difficult for corrosive media to penetrate. Simultaneously, the chelation inhibitor reacts with the hydration products to generate fluorosilicate stabilizers. These stabilizers do not chelate with citric acid and can fill pores. The filler acts as a hydrophobic agent, significantly reducing the permeation rate of citric acid solution and decreasing H+ penetration. + With Ca 2+ Contact weakens the chelation decalcification effect.

[0052] Compared with Example 1, Comparative Example 1 lacked a composite modifier, resulting in weak interfacial bonding between the polymer and the inorganic phase. Organic compounds rapidly penetrated along the interface, and the absence of hydrophobic fillers led to a violent decalcification reaction and significant loss of mass and strength. Comparative Example 2 lacked the protection of a polymer modifier, exposing the cement stone surface directly to organic acids, resulting in a significant decrease in dynamic elastic modulus and strength. Comparative Example 3 relied entirely on the corrosion resistance of the cement itself, leading to the chelation and dissolution of high-calcium hydration products, structural collapse, and the worst performance across all indicators. Comparative Example 4 used sepiolite instead of a composite modifier, which could not resist the chelation and decalcification of citric acid, nor improve interfacial bonding, resulting in rapid corrosion development.

[0053] Phenolphthalein reagent test: Cement hydration products are strongly alkaline. Phenolphthalein turns purplish-red when it comes into contact with an uncorroded alkaline matrix, representing areas with intact structure that have not been eroded by acetic acid. After acetic acid corrosion, the alkaline hydration products of the matrix are neutralized and dissolved, and the system becomes neutral or weakly acidic. Phenolphthalein can no longer show color and appears gray, which is the corroded area. The boundary between the purplish-red and gray areas is the neutral layer. The distance between the neutral layer and the surface of the specimen is the corrosion depth, which can accurately quantify the process and degree of acetic acid corrosion.

[0054] See Figure 2 and Figure 3 As shown, the distribution is the effect diagram of Example 1 and Comparative Example 1 after 60d, 90d, 120d and 180d of corrosion. With the increase of acetic acid corrosion age, the gray corrosion area continues to expand, the purplish-red uncorroded area gradually shrinks, the neutral layer continues to advance into the interior of the specimen, and the corrosion depth continues to increase. Figure 2 Example 1 compared to Figure 3 Comparative Example 1 showed no significant structural damage and demonstrated stronger long-term acid corrosion resistance.

[0055] See further Figure 4As shown, this is the XRD result of Comparative Example 1. It can be seen that the characteristic diffraction peaks match those of calcium acetate monohydrate (Ca(CH3COO)2·H2O), confirming at the phase level that the core reaction product of acetic acid corrosion of cement-based materials is calcium acetate. It should be noted that... Figure 4 In the diagram, the continuous line at the top represents the measured XRD intensity of Comparative Example 1, and the line at the bottom is the marker line.

[0056] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A cement-based material resistant to organic acid corrosion, characterized in that, According to parts by weight, it includes: 90-100 parts cement, 40-60 parts mineral admixtures, 180-220 parts river sand, 15-25 parts composite modifier, 8-12 parts polymer modifier, 6-10 parts functional additives, and 30-35 parts water. The mineral admixture includes silica fume; The preparation method of the composite modifier includes the following steps: After the filler is dried and pulverized, it is mixed with the colloidal encapsulating agent at high speed for 15-20 minutes, then the chelation inhibitor and povidone are added, the temperature is raised to 55-60℃, the mixture is kept warm and stirred for 20-25 minutes, and then cooled to room temperature to obtain the composite modifier. The mass ratio of the filler, colloidal encapsulating agent, chelation inhibitor, and povidone is 2:(3~5):(2~3):(1~2), the colloidal encapsulating agent comprises cyclodextrin and hydroxyethyl cellulose in a mass ratio of 1:(0.3~0.5), and the chelation inhibitor is selected from magnesium fluorosilicate or sodium fluorosilicate. The polymer modifier comprises an acrylic emulsion and a resin, wherein the mass ratio of the acrylic emulsion to the resin is (3~4):

1.

2. The cement-based material resistant to organic acid corrosion as described in claim 1, characterized in that: The mineral admixture also includes fly ash, and the mass ratio of fly ash to silica fume is (0.6~0.8):

1.

3. The cement-based material resistant to organic acid corrosion as described in claim 1, characterized in that: The filler includes at least one of sepiolite and diatomite.

4. The cement-based material resistant to organic acid corrosion as described in claim 3, characterized in that: The filler consists of sepiolite and diatomaceous earth in a mass ratio of 1:

1.

5. The cement-based material resistant to organic acid corrosion as described in claim 1, characterized in that: The polymer modifier uses a low-viscosity bisphenol A epoxy resin as the resin, and the preparation method of the polymer modifier includes: At room temperature and under stirring conditions, low-viscosity bisphenol A epoxy resin was added dropwise to acrylic emulsion. After the addition was complete, the temperature was raised to 45~50℃ and stirred for 20~30 minutes to obtain a polymer modifier.

6. The cement-based material resistant to organic acid corrosion as described in claim 5, characterized in that: The stirring conditions are 250~300 r / min.

7. The cement-based material resistant to organic acid corrosion as described in claim 1, characterized in that: The functional additives include water-reducing agents, expansion agents, and defoamers in a mass ratio of (3~5):(2~3):(0.5~1); The water-reducing agent is selected from polycarboxylate-based high-performance water-reducing agents, the expanding agent is selected from EP-2 plastic expanding agent, and the defoamer is selected from tributyl phosphate.

8. The cement-based material resistant to organic acid corrosion as described in claim 1, characterized in that: The conditions for drying and pulverizing the filler are as follows: place the filler in an oven and dry it at 100~105℃ for 1~2 hours, then pulverize it through a 200-mesh sieve to complete the drying and pulverizing process.

9. A method for preparing a cement-based material resistant to organic acid corrosion, used to prepare the cement-based material resistant to organic acid corrosion as described in any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Add cement, mineral admixtures, and river sand to the mixer and dry mix for 5-6 minutes. After adding the composite modifier, continue mixing for 8-10 minutes. S2. Mix water and functional additives, and add polymer modifier under stirring conditions. Stir for 8-10 minutes to obtain a mixture. S3. Under stirring conditions, the mixture is slowly added to the material obtained in S1 to obtain a mixture. S4. The mixture is placed into a mold coated with a release agent, vibrated and molded, and then cured at 18~22℃ for 22~24h before demolding. The sample is then covered with geotextile and wet-cured for 6~7 days before being taken out and naturally cured for 20~21 days until the test age.

10. The method for preparing the cement-based material resistant to organic acid corrosion as described in claim 9, characterized in that: In step S3, the stirring conditions are as follows: first stir at 250~300 r / min for 2~3 min, then stir at 550~600 r / min for 3~5 min.

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