A high-strength, corrosion-resistant ferroaluminate cement-based concrete and its preparation method

Abstract

This invention relates to the field of concrete technology, and more particularly to an early-strength, corrosion-resistant ferroaluminate cement-based concrete and its preparation method. The early-strength, corrosion-resistant ferroaluminate cement-based concrete comprises, by weight, the following raw materials: 280-400 parts ferroaluminate cement, 0-70 parts fly ash, 0-85 parts mineral powder, 0-20 parts silica fume, 670-750 parts sand, 1100-1150 parts crushed stone, 150-165 parts water, 3-6 parts a special water-reducing agent for ferroaluminate cement concrete, and 0.6-1.2 parts an internal curing nano-plant fiber emulsion. Concrete prepared by adding special water-reducing agents and internal curing materials to aluminoferrite cement can synergistically regulate the hydration of aluminoferrite cement and the adsorption of admixtures. This can improve the workability of aluminoferrite cement concrete, reduce its viscosity, enhance the slump retention over time, reduce its early hydration heat release, and improve the early mechanical properties, crack resistance, and durability of concrete. It can be widely used in marine foundation engineering such as ports, docks, and cross-sea bridges.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and in particular to an early-strength, corrosion-resistant ferroaluminate cement-based concrete and its preparation method. Background Technology

[0002] Marine infrastructure faces severe corrosion from seawater. To ensure the long service life of marine infrastructure, higher challenges and requirements will be placed on cement-based materials used in engineering. Ferroaluminate cement is the third series of cement independently developed in my country. It is a hydraulic cementitious material made by calcining raw materials to obtain clinker with anhydrous calcium sulfoaluminate, iron phase and dicalcium silicate as the main components, and adding appropriate amounts of gypsum and 0% to 10% limestone and grinding it. It has excellent properties such as rapid hardening, early strength, corrosion resistance, freeze-thaw resistance and impermeability. Due to the excellent early strength and corrosion resistance of ferroaluminate cement concrete, its use in severely corrosive marine infrastructure can significantly extend the service life of the structure.

[0003] Patent CN117447166A discloses "A Low-Heat-of-Hydration Large-Volume Ferroaluminate Cement Concrete and Its Preparation Method," which uses low-heat ferroaluminate cement, a large amount of ultrafine admixtures, properly graded sand and stone aggregates, cold water mixing, and pre-mixed mortar methods to prepare a low-heat-of-hydration large-volume ferroaluminate cement concrete. Patent CN117447168A discloses "A Low-Viscosity High-Durability Ferroaluminate Cement Concrete and Its Preparation Method," whose formula mainly involves ferroaluminate cement, steel slag powder, viscosity-reducing modifiers, sand, crushed stone, water-reducing agents, and water, and uses pre-mixed mortar and post-addition crushed stone methods to prepare low-viscosity high-durability ferroaluminate cement concrete. Patent CN116354680A discloses "A High-Crack-Resistant and High-Corrosion-Resistant Marine Concrete and Its Preparation Method," which proposes the use of modified internal curing materials, including internal curing agents, graphene nanosheets, and binders, to alleviate the problem of concentrated early-age heat release in ferroaluminate cement concrete, reduce the temperature difference between the inside and outside of the concrete, and thus reduce temperature cracks.

[0004] However, in practical engineering applications, the aforementioned aluminoferrite cement concrete exhibits high early strength and a rapid reaction rate with anhydrous calcium sulfoaluminate in its components. Consequently, the early heat release of the cement is significant and concentrated, easily leading to the following problems: 1. Poor compatibility between aluminoferrite cement and ordinary polycarboxylate superplasticizers, resulting in high cohesiveness; 2. Rapid loss of concrete fluidity and sensitivity to ambient temperature during construction, affecting on-site concrete construction; 3. Increased internal insulation temperature of the aluminoferrite cement concrete structure, which can easily cause temperature cracks. Summary of the Invention

[0005] The main objective of this invention is to provide an early-strength, corrosion-resistant ferroaluminate cement-based concrete and its preparation method, aiming to improve the technical problems of poor workability and easy temperature cracking in existing ferroaluminate cement concrete.

[0006] To achieve the above objectives, this invention proposes an early-strength, corrosion-resistant ferroaluminate cement-based concrete, comprising the following raw materials by weight: 280-400 parts ferroaluminate cement, 0-70 parts fly ash, 0-85 parts mineral powder, 0-20 parts silica fume, 670-750 parts sand, 1100-1150 parts crushed stone, 150-165 parts water, 3-6 parts ferroaluminate cement concrete-specific water-reducing agent, and 0.6-1.2 parts internal curing nano-plant fiber emulsion.

[0007] Preferably, by weight, the special water-reducing agent for aluminoferrite cement concrete comprises the following raw materials: 8-12 parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, 8-12 parts of temperature-sensitive slump-retaining polycarboxylate superplasticizer, 0-6 parts of retarder, 70-84 parts of water, 0.02-0.05 parts of defoamer, 0.02-0.06 parts of air-entraining agent, and 0.1-0.2 parts of corrosion inhibitor.

[0008] Preferably, the preparation steps of the temperature-sensitive water-reducing polycarboxylate superplasticizer and the temperature-sensitive slump-retaining polycarboxylate superplasticizer include:

[0009] S1. Preparation of unsaturated alkane amino amide intermediate: 74-102 parts of saturated alkane diamine and 13.5-17.5 parts of dehydrating agent are mixed and stirred evenly. Then, 0.75-1.00 parts of catalyst are added, and the temperature is raised to 90-105℃. 75-90 parts of unsaturated carboxylic acid are added, and the temperature is maintained for 2-4 hours until no more water is generated. The temperature is lowered to below 40℃ and 37-48 parts of 5-10% sodium bicarbonate solution are added to terminate the amidation reaction, and the unsaturated alkane amino amide intermediate is obtained.

[0010] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer: Mix 24-26 parts of the unsaturated alkane amino amide intermediate, 235-245 parts of polyoxyethylene ether macromonomer and 10-20 parts of water and stir evenly. Heat to 30-60℃ and add 14-16 parts of oxidant. Then add solution A and solution B dropwise in sequence. Finally, add 13-15 parts of sodium hydroxide solution with a concentration of 28-35% and adjust the pH to 6.0-7.0 to obtain the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0011] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer: Mix 25-26 parts of the unsaturated alkane amino amide intermediate, 240-250 parts of polyoxyethylene ether macromonomer and 20-30 parts of water and stir evenly. Heat to 30-60℃ and add 15-16 parts of oxidant. Then add solution A and solution B dropwise in sequence. Finally, add 15-16 parts of 28-35% sodium hydroxide solution and adjust the pH to 6.0-7.0 to obtain the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0012] Preferably, in step S1, 75 to 90 parts of the unsaturated carboxylic acid are added in three portions, with 1 / 3 of the total amount of unsaturated carboxylic acid added every 1.5 hours until all the carboxylic acid is added.

[0013] The saturated alkane diamine is one of 1,2-propanediamine or 2-methyl-1,2-butanediamine; the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the dehydrating agent is cyclohexane; and the catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid.

[0014] Preferably, in step S2 or step S3, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether or methyl allyl polyoxyethylene ether; the oxidant is one of hydrogen peroxide or ammonium persulfate.

[0015] Preferably, in step S2, by weight, solution A consists of 18-22 parts of unsaturated carboxylic acid and 15-20 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 1.5-3 parts of chain transfer agent and 30-40 parts of water; the time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours.

[0016] In step S3, by weight, solution A consists of 10-12 parts of unsaturated carboxylic acid, 35-39 parts of slump-preserving functional monomer, and 40-50 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 2-3 parts of chain transfer agent, and 30-40 parts of water. The time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours.

[0017] In step S2 or step S3, the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; the chain transfer agent is one of mercaptoacetic acid or mercaptopropionic acid; and in step S3, the slump-preserving functional monomer is one of hydroxyethyl acrylate or hydroxypropyl acrylate.

[0018] Preferably, the retarder is one or two of sodium gluconate, boric acid, citric acid, or sodium phosphate; the defoamer is a polyether defoamer or an organosilicon defoamer; the air-entraining agent is a mixture of rosin soap-type air-entraining agent and fatty alcohol sulfonate-type air-entraining agent in a weight ratio of 1:0.5-2; and the preservative is an isothiazolinone preservative.

[0019] In addition, this invention also proposes a method for preparing the above-mentioned early-strength corrosion-resistant ferroaluminate cement-based concrete, comprising the following steps:

[0020] S01. By weight, the aluminoferrite cement, the fly ash, the mineral powder, the silica fume, the sand, and the crushed stone are mixed and stirred for 10-15 seconds to obtain a premixed material;

[0021] S02. By weight, the water-reducing agent for ferroaluminate cement concrete and the internal curing nano-plant fiber emulsion are added to water and mixed evenly, then added to the premix and stirred evenly to obtain the early-strength corrosion-resistant ferroaluminate cement-based concrete.

[0022] Preferably, the strength grade of the aluminoferrite cement is not lower than 42.5; by mass percentage, the Fe2O3 content in the aluminoferrite cement is 6% to 10%, and the Al2O3 content is 18% to 22%.

[0023] Preferably, the internally nourishing nano-plant fiber emulsion contains internally nourishing nano-plant fibers, which are either nanocellulose fibers or nanolignin fibers, and the diameter of the internally nourishing nano-plant fibers is 5-50 nm and the length is 500-1000 nm.

[0024] Compared with the prior art, the early-strength corrosion-resistant ferroaluminate cement-based concrete and its preparation method of the present invention have the following beneficial effects:

[0025] 1. The temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer added to the early-strength corrosion-resistant ferroaluminate cement-based concrete of the present invention have alkane amino amide temperature-sensitive functional groups in their molecular structure, and have hydrophilic amide groups (-CONH-) and hydrophobic alkane amino groups [-CH2CR2NH2CH3], exhibiting different hydrophilic and hydrophobic properties at low temperature (≤37℃) and high temperature (>37℃). Traditional aluminoferrite cement concrete undergoes rapid early hydration, releasing a large amount of heat and causing the concrete to heat up quickly. When using ordinary polycarboxylate superplasticizers, they tend to be rapidly adsorbed onto the surface of cement particles, leading to a rapid loss of concrete fluidity. However, the temperature-sensitive polycarboxylate superplasticizer used in this solution can alter the hydrophilicity of its temperature-sensitive functional groups under high-temperature conditions, reducing the adsorption rate of the superplasticizer on the surface of cement particles. This allows some superplasticizer to remain in the concrete paste, exerting a long-lasting dispersion and retention effect. Furthermore, the combined use of the temperature-sensitive polycarboxylate superplasticizer and the temperature-sensitive slump-retaining superplasticizer creates temperature-sensitive superplasticizers with different adsorption rates in the concrete under high-temperature conditions. Because the temperature-sensitive slump-retaining superplasticizer's molecular structure contains not only temperature-sensitive functional groups but also slow-release ester functional groups, it has a lower adsorption rate than the temperature-sensitive superplasticizer and aluminoferrite cement, maintaining longer fluidity retention. This effectively solves the problem of rapid loss of concrete fluidity caused by concentrated early-stage heat release in aluminoferrite cement concrete.

[0026] 2. The molecular structures of temperature-sensitive water-reducing polycarboxylate superplasticizers and temperature-sensitive slump-preserving polycarboxylate superplasticizers contain alkane amino amide temperature-sensitive functional groups. In the strongly alkaline environment of concrete, they hydrolyze to generate saturated alkane diamine groups. Due to their two amino group structures, they have excellent early strength performance and can promote the early strength growth of aluminoferrite cement concrete.

[0027] 3. To address the problems of poor compatibility between aluminoferrite cement and ordinary polycarboxylate high-performance water-reducing agents, which easily leads to high cohesiveness, this invention uses two different types of air-entraining agents: rosin soap and fatty alcohol sulfonate. These agents can better maintain the stability of the internal air content of aluminoferrite cement concrete, which helps maintain the workability of the concrete, reduces the viscosity of aluminoferrite cement concrete, and facilitates the construction of aluminoferrite cement concrete.

[0028] 4. In preparing early-strength, corrosion-resistant ferroaluminate cement-based concrete, this invention selects low-heat ferroaluminate cement and adds mineral admixtures to formulate low-hydration-heat ferroaluminate cement concrete. In addition, this invention also adds an internally curing nano-plant fiber emulsion. Through the internal curing and fiber toughening effects, the crack resistance of ferroaluminate cement concrete can be significantly improved, greatly reducing the risk of cracking of ferroaluminate cement concrete. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a process diagram for the synthesis of the (temperature-sensitive functional monomer) unsaturated alkane amino amide intermediate in this scheme, where R1 is H or CH3 and R2 is H or CH2CH3;

[0031] Figure 2 The diagram shows the molecular structure of the thermosensitive water-reducing polycarboxylate superplasticizer in this scheme, where R1 is H or CH3, R2 is H or CH2CH3, and m = 45~55.

[0032] Figure 3 This is the molecular structure diagram of the thermosensitive water-reducing polycarboxylate superplasticizer in this scheme, where R1 is H or CH3, R2 is H or CH2CH3, n = 1 or 2, and m = 45~55.

[0033] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0036] This invention also proposes a method for preparing early-strength, corrosion-resistant ferroaluminate cement-based concrete, comprising the following preparation steps:

[0037] S01. By weight, 280-400 parts of aluminoferrite cement, 0-70 parts of fly ash, 0-85 parts of mineral powder, 0-20 parts of silica fume, 670-750 parts of sand, and 1100-1150 parts of crushed stone are mixed in a concrete mixer and stirred for 10-15 seconds to obtain a premixed material.

[0038] S02. By weight, add 3-6 parts of aluminoferrite cement concrete special water-reducing agent and 0.6-1.2 parts of internal curing nano plant fiber emulsion to 150-165 parts of water and mix evenly. Then add the mixture to the premix in the concrete mixer and stir for about 2 minutes to obtain the early-strength corrosion-resistant aluminoferrite cement-based concrete.

[0039] The aluminoferrite cement has a strength grade of not less than 42.5; by mass percentage, the aluminoferrite cement contains 6%–10% Fe2O3 and 18%–22% Al2O3; the internally nourishing nano-plant fiber emulsion (containing 3% solids) contains internally nourishing nano-plant fibers and water (solution component), wherein the internally nourishing nano-plant fibers are either nanocellulose fibers or nanolignin fibers, and the diameter of the internally nourishing nano-plant fibers is 5–50 nm and the length is 500–1000 nm.

[0040] The fly ash in step S01 can be Grade II, the mineral powder can be Grade S95, and the specific surface area of ​​the silicon powder is not less than 15000 m². 2 / kg, water requirement ratio not greater than 125%, 28-day activity index not less than 115%. The sand can be either river sand or manufactured sand, with a fineness modulus of 2.5 to 3.1, wherein the manufactured sand has an MB value ≤1.0, stone powder content ≤10.0%, and flaky particle content ≤5.0%; the crushed stone can be pebbles or shaped crushed stone, double-graded, triple-graded or continuously graded aggregate, with a compacted porosity of 35.0 to 37.0%; the water can be tap water or groundwater, and its properties meet the "Standard for Water Used in Concrete" (JGJ63).

[0041] Further, by weight, the special water-reducing agent for aluminoferrite cement concrete comprises the following raw materials: 8-12 parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, 8-12 parts of temperature-sensitive slump-retaining polycarboxylate superplasticizer, 0-6 parts of retarder, 70-84 parts of water, 0.02-0.05 parts of defoamer, 0.02-0.06 parts of air-entraining agent, and 0.1-0.2 parts of preservative. The retarder is one or two of sodium gluconate, boric acid, citric acid, or sodium phosphate; the defoamer is a polyether defoamer or an organosilicon defoamer; the air-entraining agent is a mixture of rosin soap-based air-entraining agent and fatty alcohol sulfonate-based air-entraining agent at a weight ratio of 1:0.5-2; and the preservative is an isothiazolinone preservative.

[0042] Furthermore, the preparation steps of the temperature-sensitive water-reducing polycarboxylate superplasticizer and the temperature-sensitive slump-retaining polycarboxylate superplasticizer include:

[0043] S1. Preparation of unsaturated alkane amino amide intermediate: 74-102 parts of saturated alkane diamine and 13.5-17.5 parts of dehydrating agent were added sequentially to the reaction vessel and mixed and stirred evenly. The stirring speed was controlled at 25-40 r / min. Then, 0.75-1.00 parts of catalyst were added. Vacuum was drawn and the pressure was controlled to below -0.09 MPa. The airtightness of the reaction device was checked. The temperature was then raised to 90-105℃. 75-90 parts of unsaturated carboxylic acid were added in 3 portions. 1 / 3 of the total amount of unsaturated carboxylic acid was added every 1.5 h until it was completely added. Then, the temperature was kept for 2-4 h until no more water came out of the water separator. The temperature was lowered to below 40℃ and 37-48 parts of 5-10% sodium bicarbonate solution were added to terminate the amidation reaction and obtain the unsaturated alkane amino amide intermediate.

[0044] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer: 24-26 parts of the unsaturated alkane amino amide intermediate, 235-245 parts of polyoxyethylene ether macromonomer and 10-20 parts of water are added sequentially to a reaction vessel, mixed and stirred evenly at a stirring speed of 25-40 r / min, heated to 30-60℃ and added 14-16 parts of oxidant, then added solution A and solution B dropwise in sequence, and finally added 13-15 parts of sodium hydroxide solution with a concentration of 28-35%, and adjusted to pH value of 6.0-7.0 to obtain temperature-sensitive water-reducing polycarboxylate superplasticizer;

[0045] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer: 25-26 parts of the unsaturated alkane amino amide intermediate, 240-250 parts of polyoxyethylene ether macromonomer, and 20-30 parts of water are added sequentially to a reaction vessel. After mixing, the mixture is stirred evenly at a stirring speed of 25-40 r / min. The temperature is raised to 30-60℃ and 15-16 parts of oxidant are added. Then, solution A and solution B are added dropwise in sequence. Finally, 15-16 parts of a 28-35% sodium hydroxide solution are added and the pH is adjusted to 6.0-7.0 to obtain the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0046] Wherein, the saturated alkane diamine is one of 1,2-propanediamine or 2-methyl-1,2-butanediamine; the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the dehydrating agent is cyclohexane; and the catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid.

[0047] In step S2 or step S3, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether (HPEG) or methyl allyl polyoxyethylene ether (TPEG); the oxidant is one of hydrogen peroxide or ammonium persulfate.

[0048] In step S2, by weight, solution A consists of 18-22 parts of unsaturated carboxylic acid and 15-20 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 1.5-3 parts of chain transfer agent and 30-40 parts of water. The time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours.

[0049] In step S3, by weight, solution A consists of 10-12 parts of unsaturated carboxylic acid, 35-39 parts of slump-preserving functional monomer, and 40-50 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 2-3 parts of chain transfer agent, and 30-40 parts of water. The time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours.

[0050] In step S2 or step S3, the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; the chain transfer agent is one of mercaptoacetic acid or mercaptopropionic acid; and in step S3, the slump-preserving functional monomer is one of hydroxyethyl acrylate or hydroxypropyl acrylate.

[0051] In summary, this solution, by adding a special water-reducing agent and internal curing material to aluminoferrite cement to produce concrete, synergistically regulates the hydration of aluminoferrite cement and the adsorption of admixtures. This not only improves the workability of aluminoferrite cement concrete and reduces its viscosity, but also enhances the slump retention over time, reduces its early hydration heat release, and strengthens the early mechanical properties, crack resistance, and durability of the concrete. It can be widely used in marine foundation engineering projects such as ports, docks, and cross-sea bridges.

[0052] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0053] Example 1

[0054] First, prepare temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer, including the following steps:

[0055] S1. First, prepare the unsaturated alkane aminoamide intermediate. Add 74 parts of 1,2-propanediamine and 13.5 parts of cyclohexane sequentially to the reaction vessel, start stirring, and control the stirring speed at 25-40 r / min. Then add 0.75 parts of concentrated sulfuric acid, evacuate the system and control the pressure to below -0.09 MPa, check the airtightness of the reaction apparatus, and then heat to 90℃. Add 75 parts of acrylic acid in three portions, adding 25 parts of acrylic acid every 1.5 hours until all the acrylic acid is added. Then keep the temperature for 4 hours until no more water comes out of the separator. Cool down to below 40℃, add 37 parts of 5% sodium bicarbonate solution to terminate the amidation reaction, and finally obtain the unsaturated alkane aminoamide intermediate.

[0056] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer. 24 parts of the unsaturated alkane amino amide intermediate, 235 parts of HPEG polyether macromonomer, and 10 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 25 r / min. After mixing and homogenization, the mixture was heated to 30℃ and 14 parts of 30% hydrogen peroxide solution were added. Then, solution A (18 parts acrylic acid and 15 parts water) was added dropwise over 2 hours, while solution B (0.4 parts vitamin C, 1.5 parts thioglycolic acid, and 30 parts water) was added dropwise over 2.5 hours, with solutions A and B added at a uniform rate. Finally, 13 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.0, yielding the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0057] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer. 25 parts of the unsaturated alkane amino amide intermediate, 240 parts of HPEG polyether macromonomer, and 20 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 25 r / min. After mixing and homogenization, the mixture was heated to 30℃ and 15 parts of 30% hydrogen peroxide solution were added. Then, solution A (10 parts acrylic acid, 35 parts hydroxyethyl acrylate, and 40 parts water) was added dropwise over 2 hours, while solution B (0.4 parts vitamin C, 2 parts thioglycolic acid, and 30 parts water) was added dropwise over 2.5 hours, controlling the addition of solutions A and B at a uniform rate. Finally, 15 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.0, obtaining the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0058] Then, a water-reducing agent specifically for aluminoferrite cement concrete is prepared, including the following steps:

[0059] Eight parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, eight parts of temperature-sensitive slump-resistant polycarboxylate superplasticizer, 84 parts of water, three parts of sodium gluconate, 0.02 parts of polyether defoamer, 0.01 parts of rosin soap air-entraining agent, 0.01 parts of fatty alcohol sulfonate air-entraining agent, and 0.1 parts of preservative were added to a mixing tank and stirred for 0.5 hours to obtain a special water-reducing agent for aluminoferrite cement concrete.

[0060] Finally, the preparation of early-strength, corrosion-resistant ferroaluminate cement-based concrete includes the following steps:

[0061] S01. By weight, add 280 parts of aluminoferrite cement, 70 parts of fly ash, 0 parts of mineral powder, 0 parts of silica fume, 750 parts of river sand, 220 parts of 5-10mm crushed stone and 880 parts of 10-25mm crushed stone to a concrete mixer and mix for 10 seconds to obtain a premixed material.

[0062] S02. Disperse 3 parts of a special water-reducing agent for ferroaluminate cement concrete and 0.6 parts of internal curing nanocellulose fiber emulsion (diameter 20nm, length 500nm, aspect ratio 25:1) in 160 parts of water, then add them to the premix in the concrete mixer and stir for 2 minutes to obtain C30 early-strength corrosion-resistant ferroaluminate cement-based concrete.

[0063] Example 2

[0064] First, prepare temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer, including the following steps:

[0065] S1. First, prepare the unsaturated alkane aminoamide intermediate. Add 102 parts of 2-methyl-1,2-butanediamine and 17.5 parts of cyclohexane sequentially to a reaction vessel, start stirring, and control the stirring speed at 40 r / min. Then add 1.0 part of concentrated sulfuric acid, evacuate the system, and control the pressure to below -0.09 MPa. Check the airtightness of the reaction apparatus, then raise the temperature to 105℃. Add 90 parts of methacrylic acid in three portions, adding 30 parts of methacrylic acid every 1.5 h until all the methacrylic acid is added. Then keep the temperature for 4 h until no more water comes out of the separator. Cool down to below 40℃, add 44 parts of 10% sodium bicarbonate solution to terminate the amidation reaction, and finally obtain the unsaturated alkane aminoamide intermediate.

[0066] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer. 24 parts of the unsaturated alkane amino amide intermediate, 245 parts of TPEG polyether macromonomer, and 20 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 40 r / min. After mixing and homogenization, the mixture was heated to 60℃ and 16 parts of ammonium persulfate were added. Then, solution A (22 parts of methacrylic acid and 15 parts of water) was added dropwise over 2 hours, while solution B (0.4 parts of vitamin C, 1.5 parts of thioglycolic acid, and 30 parts of water) was added dropwise over 2.5 hours, controlling the dropwise addition of solutions A and B at a uniform rate. Finally, 13 parts of 35% sodium hydroxide solution were added to adjust the pH to 6.8, obtaining the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0067] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer. 26 parts of the unsaturated alkane amino amide intermediate, 250 parts of HPEG polyether macromonomer, and 30 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 40 r / min. After mixing and homogenization, the mixture was heated to 60℃ and 16 parts of ammonium persulfate were added. Then, solution A (12 parts methacrylic acid, 39 parts hydroxypropyl acrylate, and 50 parts water) was added dropwise over 3 hours, while solution B (0.5 parts vitamin C, 3 parts mercaptopropionic acid, and 40 parts water) was added dropwise over 2.5 hours, controlling the dropwise addition of solutions A and B at a uniform rate. Finally, 16 parts of 35% sodium hydroxide solution were added to adjust the pH to 6.5, yielding the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0068] Then, a water-reducing agent specifically for aluminoferrite cement concrete is prepared, including the following steps:

[0069] 12 parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, 12 parts of temperature-sensitive slump-resistant polycarboxylate superplasticizer, 76 parts of water, 2 parts of sodium gluconate, 0.05 parts of organosilicon defoamer, 0.03 parts of rosin soap air-entraining agent, 0.03 parts of fatty alcohol sulfonate air-entraining agent, and 0.2 parts of preservative were added to a mixing tank and stirred for 0.5 hours to obtain a special water-reducing agent for aluminoferrite cement concrete.

[0070] Finally, the preparation of early-strength, corrosion-resistant ferroaluminate cement-based concrete includes the following steps:

[0071] S01. By weight, add 400 parts of aluminoferrite cement, 0 parts of fly ash, 80 parts of mineral powder, 0 parts of silica fume, 670 parts of river sand, 345 parts of 5-10mm crushed stone, and 805 parts of 10-25mm crushed stone to a concrete mixer and mix for 10 seconds to obtain a premixed material.

[0072] S02. Disperse 6 parts of a special water-reducing agent for aluminoferrite cement concrete and 1.2 parts of internal curing nano-lignin fiber emulsion (diameter 5nm, length 500nm, aspect ratio 100:1) in 150 parts of water, then add them to the premix in a concrete mixer and stir for 2 minutes to obtain C60 early-strength corrosion-resistant aluminoferrite cement-based concrete.

[0073] Example 3

[0074] First, prepare temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer, including the following steps:

[0075] S1. First, prepare the unsaturated alkane aminoamide intermediate. Add 74 parts of 1,2-propanediamine and 15 parts of cyclohexane sequentially to the reaction vessel, start stirring, and control the stirring speed at 30 r / min. Then add 0.85 parts of concentrated sulfuric acid, evacuate the system and control the pressure to below -0.09 MPa, check the airtightness of the reaction apparatus, and then heat to 100℃. Add 90 parts of methacrylic acid in three portions, with 30 parts of methacrylic acid added every 1.5 h until all the methacrylic acid is added. Then keep the temperature for 3 h until no more water comes out of the separator. Cool down to below 40℃, add 41 parts of 7% sodium bicarbonate solution to terminate the amidation reaction, and finally obtain the unsaturated alkane aminoamide intermediate.

[0076] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer. 25 parts of the unsaturated alkane amino amide intermediate, 240 parts of HPEG polyether macromonomer, and 15 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 30 r / min. After mixing and homogenization, the mixture was heated to 40℃ and 15 parts of 30% hydrogen peroxide solution were added. Then, solution A (19 parts acrylic acid and 18 parts water) was added dropwise over 2.5 h, while solution B (0.45 parts vitamin C, 2 parts thioglycolic acid, and 35 parts water) was added dropwise over 3.0 h, controlling the addition of solutions A and B at a uniform rate. Finally, 14 parts of 30% sodium hydroxide solution were added to adjust the pH to 7.0, obtaining the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0077] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer. 25 parts of the unsaturated alkane amino amide intermediate, 245 parts of HPEG polyether macromonomer, and 25 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 30 r / min. After mixing and homogenization, the mixture was heated to 40℃ and 15.5 parts of 30% hydrogen peroxide solution were added. Then, solution A (10 parts acrylic acid, 39 parts hydroxypropyl acrylate, and 45 parts water) was added dropwise over 2.5 h, while solution B (0.45 parts vitamin C, 2.5 parts mercaptoacetic acid, and 35 parts water) was added dropwise over 3.0 h, controlling the addition of solutions A and B at a uniform rate. Finally, 15.5 parts of 30% sodium hydroxide solution were added to adjust the pH to 7.0, yielding the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0078] Then, a water-reducing agent specifically for aluminoferrite cement concrete is prepared, including the following steps:

[0079] Ten parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, ten parts of temperature-sensitive slump-resistant polycarboxylate superplasticizer, 76 parts of water, 2 parts of boric acid, 2 parts of sodium gluconate, 0.04 parts of polyether defoamer, 0.02 parts of rosin soap air-entraining agent, 0.01 parts of fatty alcohol sulfonate air-entraining agent, and 0.15 parts of preservative were added to a mixing tank and stirred for 0.5 hours to obtain a special water-reducing agent for aluminoferrite cement concrete.

[0080] Finally, the preparation of early-strength, corrosion-resistant ferroaluminate cement-based concrete includes the following steps:

[0081] S01. By weight, add 315 parts of aluminoferrite cement, 0 parts of fly ash, 85 parts of mineral powder, 20 parts of silica fume, 690 parts of manufactured sand, 340 parts of 5-10mm crushed stone, and 790 parts of 10-25mm crushed stone to a concrete mixer and mix for 10 seconds to obtain a premix.

[0082] S02. Disperse 5 parts of a special water-reducing agent for ferroaluminate cement concrete and 1.0 part of an internal curing nanocellulose fiber emulsion (diameter 50nm, length 1000nm, aspect ratio 20:1) in 160 parts of water, then add it to the premix in a concrete mixer and stir for 2 minutes to obtain C40 early-strength corrosion-resistant ferroaluminate cement-based concrete.

[0083] Example 4

[0084] First, prepare temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer, including the following steps:

[0085] S1. First, prepare the unsaturated alkane aminoamide intermediate. Add 102 parts of 2-methyl-1,2-butanediamine and 16 parts of cyclohexane sequentially to a reaction vessel, start stirring, and control the stirring speed at 35 r / min. Then add 0.9 parts of concentrated sulfuric acid, evacuate the system, and control the pressure to below -0.09 MPa. Check the airtightness of the reaction apparatus, then raise the temperature to 95℃. Add 75 parts of acrylic acid in three portions, adding 25 parts of acrylic acid every 1.5 h until all the acrylic acid is added. Then keep the temperature for 4 h until no more water comes out of the separator. Cool down to below 40℃, add 44 parts of 5% sodium bicarbonate solution to terminate the amidation reaction, and finally obtain the unsaturated alkane aminoamide intermediate.

[0086] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer. 24 parts of the unsaturated alkane amino amide intermediate, 240 parts of TPEG polyether macromonomer, and 15 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 35 r / min. After mixing and homogenization, the mixture was heated to 50℃ and 15 parts of 30% hydrogen peroxide solution were added. Then, solution A (21 parts of methacrylic acid and 19 parts of water) was added dropwise over 3.0 h, while solution B (0.5 parts of vitamin C, 2.5 parts of mercaptopropionic acid, and 38 parts of water) was added dropwise over 3.5 h, controlling the dropwise addition of solutions A and B at a uniform rate. Finally, 14.5 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.5, obtaining the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0087] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer. 25.5 parts of the unsaturated alkane amino amide intermediate, 240 parts of TPEG polyether macromonomer, and 30 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 35 r / min. After mixing and homogenization, the mixture was heated to 50℃ and 15.5 parts of 30% hydrogen peroxide solution were added. Then, solution A (12 parts methacrylic acid, 35 parts hydroxyethyl acrylate, and 43 parts water) was added dropwise over 3.0 h, while solution B (0.46 parts vitamin C, 2.4 parts mercaptoacetic acid, and 37 parts water) was added dropwise over 3.5 h, controlling the addition of solutions A and B at a uniform rate. Finally, 16.0 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.0, obtaining the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0088] Then, a water-reducing agent specifically for aluminoferrite cement concrete is prepared, including the following steps:

[0089] Nine parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, nine parts of temperature-sensitive slump-resistant polycarboxylate superplasticizer, 76 parts of water, 2 parts of citric acid, 3 parts of sodium phosphate, 0.03 parts of polyether defoamer, 0.02 parts of rosin soap air-entraining agent, 0.03 parts of fatty alcohol sulfonate air-entraining agent, and 0.2 parts of preservative were added to a mixing tank and stirred for 0.5 hours to obtain a special water-reducing agent for aluminoferrite cement concrete.

[0090] Finally, the preparation of early-strength, corrosion-resistant ferroaluminate cement-based concrete includes the following steps:

[0091] S01. By weight, add 285 parts of aluminoferrite cement, 57 parts of fly ash, 38 parts of mineral powder, 0 parts of silica fume, 695 parts of manufactured sand, 340 parts of 5-10mm crushed stone, and 800 parts of 10-25mm crushed stone to a concrete mixer and mix for 10 seconds to obtain a premix.

[0092] S02. Disperse 4.5 parts of a special water-reducing agent for aluminoferrite cement concrete and 0.9 parts of internal curing nano-lignin fiber emulsion (diameter 30nm, length 900nm, aspect ratio 30:1) in 165 parts of water, then add them to the premix in a concrete mixer and stir for 2 minutes to obtain C35 early-strength corrosion-resistant aluminoferrite cement-based concrete.

[0093] Comparative Example 1

[0094] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that when preparing aluminoferrite cement-based concrete, a traditional silicate cement concrete water-reducing agent is used instead of the aluminoferrite cement concrete water-reducing agent used in this scheme (i.e., temperature-sensitive water-reducing and slump-retaining polycarboxylate water-reducing agent is not used).

[0095] Specifically, the preparation of aluminoferrite cement-based concrete includes the following steps:

[0096] S01. By weight, add 280 parts of aluminoferrite cement, 70 parts of fly ash, 0 parts of mineral powder, 0 parts of silica fume, 750 parts of river sand, 220 parts of 5-10mm crushed stone, and 880 parts of 10-25mm crushed stone to the concrete mixer and mix for 10 seconds.

[0097] S02. Disperse 3 parts of silicate cement concrete water-reducing agent and 0.6 parts of internal curing nanocellulose fiber emulsion in 160 parts of water, then add them to a concrete mixer and stir for 2 minutes to obtain C30 aluminoferrite cement-based concrete.

[0098] Comparative Example 2

[0099] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that when preparing the temperature-sensitive water-reducing polycarboxylate superplasticizer and the slump-retaining polycarboxylate superplasticizer, the unsaturated alkane amino amide intermediate was not prepared, and N-isopropylacrylamide was directly used to replace the unsaturated alkane amino amide intermediate.

[0100] Comparative Example 3

[0101] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that the water-reducing agent for ferroaluminate cement concrete is a temperature-sensitive water-reducing polycarboxylate water-reducing agent and a common slump-retaining water-reducing agent, with the common slump-retaining water-reducing agent replacing the temperature-sensitive slump-retaining water-reducing agent.

[0102] Comparative Example 4

[0103] In this comparative example, all preparation steps and parameters are the same as in Example 1, except that the internal curing nanocellulose fiber emulsion is not added in the preparation of aluminoferrite cement concrete.

[0104] Comparative Example 5

[0105] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that only temperature-sensitive water-reducing polycarboxylate superplasticizer is added to the raw materials of the water-reducing agent for aluminoferrite cement concrete, and temperature-sensitive slump-preserving polycarboxylate superplasticizer is not added.

[0106] Comparative Example 6

[0107] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that only temperature-sensitive slump-preserving polycarboxylate superplasticizer is added to the raw materials of the water-reducing agent for aluminoferrite cement concrete, and no temperature-sensitive water-reducing polycarboxylate superplasticizer is added.

[0108] Comparative Example 7

[0109] In this comparative example, all preparation steps and parameters are the same as in Example 1. The difference is that when preparing the special water-reducing agent for iron-aluminate cement concrete, only one type of air-entraining agent - fatty alcohol sulfonate air-entraining agent 0.02 parts is added.

[0110] The early-strength corrosion-resistant aluminoferrite cement-based concretes prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance testing. The test results are shown in the table below:

[0111] Table 1. Basic physical and mechanical properties of aluminoferrite cement concrete

[0112]

[0113]

[0114] As can be seen from the test results in Table 1 above, the early-strength corrosion-resistant ferroaluminate cement-based concrete prepared in Examples 1 to 4 of the present invention has good workability and small slump loss after 1 hour; it has high early strength, with the compressive strength of the concrete reaching the corresponding concrete strength grade at 3 days and a significant increase in compressive strength at 28 days; in addition, the concrete has good durability, with the electrical flux not exceeding 300C at both 3 days and 28 days, making it suitable for concrete structures of marine infrastructure such as ports, docks, and cross-sea bridges.

[0115] Compared with Example 1, Comparative Example 1 uses a silicate cement concrete water-reducing agent instead of the aluminoferrite cement concrete water-reducing agent in this scheme. The resulting concrete has poor workability and is generally sticky, with a large slump loss over time. Compared with Example 1, the early strength adiabatic temperature rise of the concrete is increased, indicating that the silicate cement concrete water-reducing agent has a small effect on delaying cement hydration when used in aluminoferrite cement concrete. The compressive strength and durability (electrical flux) of the concrete are both worse than those of Example 1.

[0116] Compared to Example 1, Comparative Example 2, which uses N-isopropylacrylamide instead of the unsaturated alkane aminoamide intermediate, exhibits a higher hydration exothermic temperature for aluminoferrite cement concrete, resulting in greater slump loss over time and poorer mechanical properties and durability. This demonstrates that the temperature-sensitive water-reducing polycarboxylate superplasticizer and slump-retaining polycarboxylate superplasticizer prepared using the temperature-sensitive functional monomer unsaturated alkane aminoamide intermediate of this invention have better adaptability to aluminoferrite cement concrete.

[0117] Compared with Example 1, Comparative Example 3 only used a temperature-sensitive water-reducing agent. When a common slump-retaining water-reducing agent was used instead of the temperature-sensitive slump-retaining agent, the slump loss of the concrete in 1 hour was large. However, compared with Comparative Example 1, which used both common and slump-retaining agents, the slump loss of the concrete in 1 hour was reduced. In addition, the thermal insulation temperature of the concrete in Comparative Example 3 was higher than that in Example 1, the compressive strength was lower than that in Example 1, and the electrical flux was higher than that in Example 1.

[0118] Compared to Example 1, Comparative Example 4, without the addition of internally cured nanocellulose fiber emulsion during the preparation of aluminoferrite cement concrete, resulted in poorer concrete cohesiveness, a slightly higher adiabatic temperature rise, a slightly lower compressive strength, and a slightly higher electrical flux. This indicates that the internally cured nanocellulose fiber emulsion can improve the cohesiveness of aluminoferrite cement concrete, enhance its mechanical properties and electrical flux properties, and, due to its internal curing and fiber toughening functions, further enhance the crack resistance of aluminoferrite cement concrete.

[0119] Compared to Example 1, Comparative Example 5, which used a water-reducing agent for aluminoferrite cement concrete, only added a temperature-sensitive polycarboxylate superplasticizer without adding a temperature-sensitive slump-maintaining polycarboxylate superplasticizer. The concrete had good initial workability, but significant slump loss, reduced thermal temperature rise, decreased compressive strength, and increased electrical flux. This indicates that adding only the temperature-sensitive slump-maintaining polycarboxylate superplasticizer results in significant slump loss, which is detrimental to on-site concrete construction.

[0120] Compared to Example 1, Comparative Example 6, which used a water-reducing agent for aluminoferrite cement concrete, only added a temperature-sensitive slump-retaining polycarboxylate superplasticizer, without adding a temperature-sensitive water-reducing polycarboxylate superplasticizer, showed good initial workability but generally poor initial fluidity. The slump loss was still greater than in Example 1, with increased adiabatic temperature rise, increased compressive strength, and decreased electrical flux. This indicates that adding only the temperature-sensitive slump-retaining polycarboxylate superplasticizer results in poor concrete fluidity at the mixer and significant slump loss, which is detrimental to on-site concrete construction. A comprehensive comparison of Examples 3, 5, and 6 demonstrates that for aluminoferrite cement concrete, the combination of the temperature-sensitive water-reducing polycarboxylate superplasticizer and the temperature-sensitive slump-retaining polycarboxylate superplasticizer in this scheme provides superior slump retention over time, delayed hydration heat release, mechanical properties, and electrical flux compared to using only the temperature-sensitive water-reducing agent, conventional slump-retaining superplasticizer, or a combination of both.

[0121] Compared to Example 1, Comparative Example 7, which added only 0.02 parts of a fatty alcohol sulfonate air-entraining agent to prepare the water-reducing agent for aluminoferrite cement concrete, showed slightly worse workability than Example 1. This resulted in a slightly larger slump loss, increased adiabatic temperature rise, reduced strength, and increased electrical flux. This was mainly due to the uneven distribution of air pores within the concrete, leading to a slight decrease in concrete strength and a slight increase in electrical flux.

[0122] Example 5

[0123] In this embodiment, all preparation steps and parameters are the same as in Example 1, except that the weight ratios of the temperature-sensitive water-reducing polycarboxylate superplasticizer and the temperature-sensitive slump-retaining polycarboxylate superplasticizer are different, as shown in the table below:

[0124]

[0125] The early-strength corrosion-resistant aluminoferrate cement-based concrete prepared in Example 5 above was subjected to performance testing. The test results are shown in the table below:

[0126] Table 2 Basic physical and mechanical properties of aluminoferrite cement concrete

[0127]

[0128] As shown in Table 2 above, when preparing the special water-reducing agent for aluminoferrite cement concrete, this method further limits the weight ratio of temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer to (8-11): (8-10). This improves the slump retention, hydration heat release, compressive strength, and electrical flux performance of the prepared early-strength corrosion-resistant aluminoferrite cement-based concrete. Among them, the concrete performance is relatively optimal when the weights of temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer are 8 parts and 10 parts, respectively.

[0129] Example 6

[0130] In this embodiment, all preparation steps and parameters are the same as in Example 1, except that the parameters of the internally maintained nanocellulose fibers are different, as shown in the table below:

[0131]

[0132] The early-strength corrosion-resistant aluminoferrite cement-based concrete prepared in Example 6 above was subjected to performance testing. The test results are shown in the table below:

[0133] Table 3 Basic physical and mechanical properties of aluminoferrite cement concrete

[0134]

[0135]

[0136] As can be seen from the test results in Table 3 above, the internal curing nano-plant fiber emulsion used in this scheme is preferably a combination of two fibers. The preferred weight ratio of nanocellulose fiber to nanolignin fiber is (1-2):(1-2), and the aspect ratio of nanocellulose fiber is preferably limited to (30-40):1, and the aspect ratio of nanolignin fiber is preferably limited to (20-25):1. This can improve the slump retention, compressive strength, and electrical conductivity of the early-strength corrosion-resistant aluminoferrite cement-based concrete. Among them, the concrete performance is relatively optimal when the weight ratio of nanocellulose fiber (aspect ratio of 40:1) and nanolignin fiber (aspect ratio of 20:1) is 2:1.

[0137] Example 7

[0138] First, prepare temperature-sensitive water-reducing polycarboxylate superplasticizer and temperature-sensitive slump-retaining polycarboxylate superplasticizer, including the following steps:

[0139] S1. First, prepare the unsaturated alkane aminoamide intermediate. Add 102 parts of 2-methyl-1,2-butanediamine and 16 parts of cyclohexane sequentially to a reaction vessel, start stirring, and control the stirring speed at 35 r / min. Then add 0.9 parts of concentrated sulfuric acid, evacuate the system, and control the pressure to below -0.09 MPa. Check the airtightness of the reaction apparatus, then raise the temperature to 105℃. Add 75 parts of acrylic acid in three portions, adding 25 parts of acrylic acid every 1.5 h until all the acrylic acid is added. Then keep the temperature for 4 h until no more water comes out of the separator. Cool down to below 40℃, add 44 parts of 5% sodium bicarbonate solution to terminate the amidation reaction, and finally obtain the unsaturated alkane aminoamide intermediate.

[0140] S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer. 24 parts of the unsaturated alkane amino amide intermediate, 240 parts of TPEG polyether macromonomer, and 15 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 35 r / min. After mixing and homogenization, the mixture was heated to 40℃ and 15 parts of 30% hydrogen peroxide solution were added. Then, solution A (21 parts of methacrylic acid and 19 parts of water) was added dropwise over 3.0 h, while solution B (0.5 parts of vitamin C, 2.5 parts of mercaptopropionic acid, and 38 parts of water) was added dropwise over 3.5 h, controlling the dropwise addition of solutions A and B at a uniform rate. Finally, 14.5 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.5, obtaining the temperature-sensitive water-reducing polycarboxylate superplasticizer.

[0141] S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer. 25.5 parts of the unsaturated alkane amino amide intermediate, 240 parts of TPEG polyether macromonomer, and 30 parts of water were sequentially added to a reaction vessel. Stirring was started, with the stirring speed controlled at 35 r / min. After mixing and homogenization, the mixture was heated to 40℃ and 15.5 parts of 30% hydrogen peroxide solution were added. Then, solution A (12 parts methacrylic acid, 35 parts hydroxyethyl acrylate, and 43 parts water) was added dropwise over 3.0 h, while solution B (0.46 parts vitamin C, 2.4 parts mercaptoacetic acid, and 37 parts water) was added dropwise over 3.5 h, controlling the addition of solutions A and B at a uniform rate. Finally, 16.0 parts of 28% sodium hydroxide solution were added to adjust the pH to 6.5, obtaining the temperature-sensitive slump-retaining polycarboxylate superplasticizer.

[0142] Then, a water-reducing agent specifically for aluminoferrite cement concrete is prepared, including the following steps:

[0143] Eight parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, ten parts of temperature-sensitive slump-resistant polycarboxylate superplasticizer, 76 parts of water, two parts of sodium gluconate, two parts of sodium phosphate, 0.03 parts of polyether defoamer, 0.02 parts of rosin soap air-entraining agent, 0.02 parts of fatty alcohol sulfonate air-entraining agent, and 0.2 parts of preservative were added to a mixing tank and stirred for 0.5 hours to obtain a special water-reducing agent for aluminoferrite cement concrete.

[0144] Finally, the preparation of early-strength, corrosion-resistant ferroaluminate cement-based concrete includes the following steps:

[0145] S01. By weight, add 280 parts of aluminoferrite cement, 70 parts of fly ash, 0 parts of mineral powder, 0 parts of silica fume, 750 parts of river sand, 220 parts of 5-10mm crushed stone and 880 parts of 10-25mm crushed stone to a concrete mixer and mix for 10 seconds to obtain a premixed material.

[0146] S02. Disperse 3 parts of a special water-reducing agent for aluminoferrite cement concrete and 0.6 parts of an internal curing nanocellulose fiber emulsion (the weight ratio of nanocellulose fiber and nanolignin fiber is 2:1, the solid content is 3%, wherein the length of the nanocellulose fiber is 1000nm, the diameter is 25nm, and the aspect ratio is 40:1; the length of the nanolignin fiber is 500nm, the diameter is 25nm, and the aspect ratio is 20:1) in 160 parts of water, then add it to the premix in the concrete mixer and stir for 2 minutes to obtain C30 early-strength corrosion-resistant aluminoferrite cement-based concrete.

[0147] The early-strength corrosion-resistant ferroaluminate cement-based concrete prepared in Example 7 above was subjected to performance testing. The test results are shown in the table below:

[0148] Table 4. Basic physical and mechanical properties of aluminoferrite cement concrete

[0149]

[0150] As can be seen from the test results in Table 4 above, after comprehensive optimization of raw materials, proportions and parameters of each raw material, the early-strength corrosion-resistant ferroaluminate cement-based concrete has very good workability, with no loss of slump after 1 hour; the early strength of the concrete is high, and the compressive strength of the concrete can reach 35.8 MPa after 3 days; the electrical flux of the concrete can be reduced to below 260°C at 3 days or 28 days, and it has excellent durability.

[0151] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the patent. The fluranar sodium solution mentioned in the present invention is not limited to the above-mentioned types. Therefore, the above embodiments should not be regarded as a limitation on the scope of protection of the present invention. All equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A high-strength, corrosion-resistant ferroaluminate cement-based concrete, characterized in that, By weight, it includes the following raw materials: 280-400 parts of aluminoferrite cement, 0-70 parts of fly ash, 0-85 parts of mineral powder, 0-20 parts of silica fume, 670-750 parts of sand, 1100-1150 parts of crushed stone, 150-165 parts of water, 3-6 parts of aluminoferrite cement concrete-specific water-reducing agent, and 0.6-1.2 parts of internal curing nano-plant fiber emulsion; By weight, the special water-reducing agent for aluminoferrite cement concrete comprises the following raw materials: 8-12 parts of temperature-sensitive water-reducing polycarboxylate superplasticizer, 8-12 parts of temperature-sensitive slump-retaining polycarboxylate superplasticizer, 0-6 parts of retarder, 70-84 parts of water, 0.02-0.05 parts of defoamer, 0.02-0.06 parts of air-entraining agent, and 0.1-0.2 parts of corrosion inhibitor; The preparation steps of the temperature-sensitive water-reducing polycarboxylate superplasticizer and the temperature-sensitive slump-retaining polycarboxylate superplasticizer include: S1. Preparation of unsaturated alkane amino amide intermediate: Mix 74-102 parts of saturated alkane diamine and 13.5-17.5 parts of dehydrating agent and stir evenly. Then add 0.75-1.00 parts of catalyst, heat to 90-105℃, add 75-90 parts of unsaturated carboxylic acid, keep warm for 2-4 hours until no more water is generated, cool down to below 40℃ and add 37-48 parts of 5-10% sodium bicarbonate solution to terminate the amidation reaction and obtain unsaturated alkane amino amide intermediate; S2. Preparation of temperature-sensitive water-reducing polycarboxylate superplasticizer: Mix 24-26 parts of the unsaturated alkane amino amide intermediate, 235-245 parts of polyoxyethylene ether macromonomer and 10-20 parts of water and stir evenly. Heat to 30-60℃ and add 14-16 parts of oxidant. Then add solution A and solution B dropwise in sequence. Finally, add 13-15 parts of sodium hydroxide solution with a concentration of 28-35% and adjust the pH value to 6.0-7.0 to obtain the temperature-sensitive water-reducing polycarboxylate superplasticizer. S3. Preparation of temperature-sensitive slump-retaining polycarboxylate superplasticizer: Mix 25-26 parts of the unsaturated alkane amino amide intermediate, 240-250 parts of polyoxyethylene ether macromonomer and 20-30 parts of water and stir evenly. Heat to 30-60℃ and add 15-16 parts of oxidant. Then add solution A and solution B dropwise in sequence. Finally, add 15-16 parts of sodium hydroxide solution with a concentration of 28-35% and adjust the pH to 6.0-7.0 to obtain the temperature-sensitive slump-retaining polycarboxylate superplasticizer. In step S2, by weight, solution A consists of 18-22 parts of unsaturated carboxylic acid and 15-20 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 1.5-3 parts of chain transfer agent and 30-40 parts of water. The time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours. In step S3, by weight, solution A consists of 10-12 parts of unsaturated carboxylic acid, 35-39 parts of slump-preserving functional monomer, and 40-50 parts of water; by weight, solution B consists of 0.4-0.5 parts of reducing agent, 2-3 parts of chain transfer agent, and 30-40 parts of water. The time for adding solution A is 2-3 hours, and the time for adding solution B is 2.5-3.5 hours.

2. The early-strength, corrosion-resistant ferroaluminate cement-based concrete according to claim 1, characterized in that, In step S1, 75-90 parts of the unsaturated carboxylic acid are added in three portions, with 1 / 3 of the total amount of unsaturated carboxylic acid added every 1.5 hours until all the carboxylic acid is added. The saturated alkane diamine is one of 1,2-propanediamine or 2-methyl-1,2-butanediamine; the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the dehydrating agent is cyclohexane; and the catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid.

3. The early-strength, corrosion-resistant ferroaluminate cement-based concrete according to claim 1, characterized in that, In step S2 or step S3, the polyoxyethylene ether macromonomer is one of allyl polyoxyethylene ether or methyl allyl polyoxyethylene ether; the oxidant is one of hydrogen peroxide or ammonium persulfate.

4. The early-strength, corrosion-resistant ferroaluminate cement-based concrete according to claim 1, characterized in that, In step S2 or step S3, the unsaturated carboxylic acid is one of acrylic acid or methacrylic acid; the reducing agent is vitamin C; the chain transfer agent is one of mercaptoacetic acid or mercaptopropionic acid; and in step S3, the slump-preserving functional monomer is one of hydroxyethyl acrylate or hydroxypropyl acrylate.

5. The early-strength, corrosion-resistant ferroaluminate cement-based concrete according to claim 1, characterized in that, The retarder is one or two of sodium gluconate, boric acid, citric acid, or sodium phosphate; the defoamer is a polyether defoamer or an organosilicon defoamer; the air-entraining agent is a mixture of rosin soap-type air-entraining agent and fatty alcohol sulfonate-type air-entraining agent in a weight ratio of 1:0.5~2; and the preservative is an isothiazolinone preservative.

6. A method for preparing early-strength corrosion-resistant ferroaluminate cement-based concrete as described in any one of claims 1-5, characterized in that, Includes the following steps: S01. By weight, the aluminoferrite cement, the fly ash, the mineral powder, the silica fume, the sand, and the crushed stone are mixed and stirred for 10-15 seconds to obtain a premixed material; S02. By weight, the water-reducing agent for ferroaluminate cement concrete and the internal curing nano-plant fiber emulsion are added to water and mixed evenly, then added to the premix and stirred evenly to obtain the early-strength corrosion-resistant ferroaluminate cement-based concrete.

7. The method for preparing early-strength corrosion-resistant ferroaluminate cement-based concrete according to claim 6, characterized in that, The strength grade of the aluminoferrite cement is not lower than 42.5; by mass percentage, the Fe2O3 content in the aluminoferrite cement is 6%~10%, and the Al2O3 content is 18%~22%.

8. The method for preparing early-strength corrosion-resistant ferroaluminate cement-based concrete according to claim 6, characterized in that, The internally nourishing nano-plant fiber emulsion contains internally nourishing nano-plant fibers, which are either nanocellulose fibers or nanolignin fibers. The diameter of the internally nourishing nano-plant fibers is 5~50nm and the length is 500~1000nm.

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