A high-performance low-carbon concrete additive, its preparation method and application

Abstract

The present invention belongs to the technical field of building materials, and specifically relates to a high-performance low-carbon concrete additive, its preparation method and application. The additive comprises the following raw materials in parts by weight: 70-80 parts of water reducing agent, 5-10 parts of modified nano-hydroxyapatite, 8-15 parts of fly ash, 20-30 parts of slag, 9-14 parts of montmorillonite cyclodextrin complex; the preparation process of the modified nano-hydroxyapatite is as follows: nano-hydroxyapatite, carboxymethyl cellulose and saturated fatty acid are added into an ethanol solution for heat reflux reaction, and the reaction solution is obtained by removing the solvent, washing with water and drying to obtain modified nano-hydroxyapatite. The additive of the present invention contains components such as modified nano-hydroxyapatite, montmorillonite cyclodextrin complex and water reducing agent. Among them, the modified nano-hydroxyapatite can improve the compressive strength of concrete, and the combined use of montmorillonite cyclodextrin complex and water reducing agent can improve the fluidity of concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a high-performance low-carbon concrete additive, a preparation method thereof, and an application thereof. Background Art

[0002] The main component of the cementitious material is concrete, so the preparation and use of concrete are crucial. Based on the above background, low-carbon concrete has gradually come into people's view.

[0003] Reducing the cement dosage can reduce the carbon emissions of concrete. At present, the methods for reducing the cement dosage of concrete include increasing the dosage of mineral admixtures, modifying water reducers, using concrete additives such as synergists and enhancers, etc. For example, Chinese Patent CN117756439A, a low-carbon concrete admixture, its preparation method and application, discloses the use of industrial by-products rich in silicon and aluminum to prepare low-carbon concrete to reduce the cement dosage. Chinese Patent CN118344083A, a super-high-performance low-carbon concrete and its preparation method, discloses benzoic anhydride / organosilicon-modified polycarboxylate water reducer to reduce the cement dosage. However, it is difficult for the above-mentioned solutions to simultaneously achieve excellent strength and other properties of concrete while reducing carbon emissions. Chinese Patent CN117964276A, a low-carbon concrete additive, its preparation method and application, discloses increasing the use of concrete additives to reduce the cement dosage. However, the concrete prepared with this additive has the problem of poor fluidity. Based on the above background, the present invention provides a high-performance low-carbon concrete additive, which can ensure excellent compressive strength and fluidity of concrete while reducing carbon emissions. Summary of the Invention

[0004] The first object of the present invention is to provide a high-performance low-carbon concrete additive, in which the modified nano-hydroxyapatite can improve the compressive strength of the obtained concrete; the montmorillonite cyclodextrin complex can improve the fluidity of the obtained concrete.

[0005] The second object of the present invention is to provide a preparation method of a high-performance low-carbon concrete additive.

[0006] The third object of the present invention is to provide an application of a high-performance low-carbon concrete additive, and the application prospect is broad.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A high-performance low-carbon concrete additive, comprising the following raw materials in parts by weight: 70-80 parts of water reducer, 5-10 parts of modified nano-hydroxyapatite, 8-15 parts of fly ash, 20-30 parts of slag, 9-14 parts of montmorillonite cyclodextrin complex;

[0009] The preparation process of the modified nano-hydroxyapatite is as follows: Nano-hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid are added to an ethanol solution for heat reflux reaction. After the reaction solution is subjected to solvent removal, water washing, and drying, the modified nano-hydroxyapatite is obtained.

[0010] In the present invention, the surface of the modified nano-hydroxyapatite is grafted with a long-chain alkyl structure, which enhances the bonding force between the nano-hydroxyapatite and the cement matrix, and thus improves the mechanical properties of the concrete.

[0011] Preferably, the mass ratio of the nano-hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid is 1:(4 - 7):(3 - 8); the saturated fatty acid is dodecanoic acid.

[0012] Preferably, the mass concentration of ethanol in the ethanol solution is 40 - 55 wt%; the time of the reflux reaction is 3.5 - 4.5 h.

[0013] Preferably, the preparation process of the montmorillonite cyclodextrin complex is as follows:

[0014] (1) Montmorillonite is treated with an acidic solution and calcined to obtain calcined montmorillonite; the calcined montmorillonite is activated with a surfactant to obtain modified montmorillonite;

[0015] (2) β-cyclodextrin is dissolved in an aqueous solution of sodium hydroxide, 2,3-epoxypropyltrimethylammonium chloride is added, and the mixture is heated and stirred for reaction. After discharging, it is washed and dried to obtain a β-cyclodextrin cationic derivative;

[0016] (3) The modified montmorillonite obtained in step (1) and the β-cyclodextrin cationic derivative obtained in step (2) are added to water, and the mixture is shaken at room temperature and then centrifuged to obtain a montmorillonite cyclodextrin complex.

[0017] After the calcined montmorillonite is activated with the surfactant sodium dodecylbenzenesulfonate, its surface is negatively charged, and it can adsorb and bind to the cationic β-cyclodextrin derivative through electrostatic interaction and porous structure, thereby improving the dispersion and suspension state of cement particles in the concrete, and thus improving the fluidity of the concrete.

[0018] Preferably, in step (1), the solid-liquid ratio of the montmorillonite to the acidic solution is 1 g:(15 - 20) mL, and the acidic solution is a hydrochloric acid solution with a concentration of 1 - 2 mol / L; the calcination temperature is 460 - 550 °C, and the time is 0.8 - 1.5 h; the mass ratio of the calcined montmorillonite to the surfactant is 1:(1.5 - 2.5), and the surfactant is sodium dodecylbenzenesulfonate.

[0019] Preferably, in step (2), the mass ratio of β-cyclodextrin to 2,3-epoxypropyltrimethylammonium chloride is 1:(0.1 - 0.3); the concentration of the aqueous sodium hydroxide solution is 0.1 - 0.2 mol / L; the temperature of the heating and stirring is 40 - 50 °C, and the time is 1.2 - 2.5 h; in step (3), the mass ratio of the modified montmorillonite to the β-cyclodextrin cationic derivative is 1:(20 - 28).

[0020] Preferably, the water reducer is a polycarboxylate superplasticizer with a water reducing rate of 30%.

[0021] The preparation method of the above high-performance low-carbon concrete additive includes the following steps:

[0022] Weigh each raw material according to the weight ratio. After uniformly mixing the modified nano-hydroxyapatite, fly ash, slag, and montmorillonite cyclodextrin complex, then add the water reducer and mix uniformly to obtain the product.

[0023] The application of the above high-performance low-carbon concrete additive in the preparation of high-performance low-carbon concrete.

[0024] Preferably, the low-carbon concrete is composed of the following raw materials in parts by weight: 4 - 7 parts of high-performance low-carbon concrete additive, 80 - 95 parts of cement, 130 - 140 parts of water, 150 - 180 parts of silica fume, 80 - 100 parts of metakaolin, 650 - 700 parts of manufactured sand, and 900 - 1000 parts of crushed stone.

[0025] When the additive of the present invention is applied to low-carbon concrete, the cement dosage in the concrete can be reduced by 40 - 50%.

[0026] Compared with the prior art, the beneficial effects of the present invention mainly lie in:

[0027] The high-performance low-carbon concrete additive of the present invention contains components such as modified nano-hydroxyapatite, montmorillonite cyclodextrin complex, and water reducer. Among them, the modified nano-hydroxyapatite can improve the compressive strength of concrete, and the combined use of the montmorillonite cyclodextrin complex and the water reducer can improve the fluidity of concrete. In addition, the low-carbon concrete prepared using the low-carbon additive of the present invention also has excellent sulfate erosion resistance and seawater erosion resistance. Specific Embodiments

[0028] The following further describes the technical solutions of the present invention in combination with specific embodiments. However, those skilled in the art should understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the present invention. The specific conditions not specified in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are all conventional products obtained through commercial channels without special instructions.

[0029] 1. Example

[0030] Example 1

[0031] A high-performance low-carbon concrete additive, which is composed of the following raw materials in parts by weight: 72 parts of polycarboxylate high-performance water reducer (water reduction rate is 30%), 7 parts of modified nano-hydroxyapatite, 11 parts of fly ash, 23 parts of slag, and 10 parts of montmorillonite cyclodextrin complex.

[0032] Among them, the preparation process of the modified nano-hydroxyapatite is as follows:

[0033] According to the mass ratio of nano-hydroxyapatite, carboxymethyl cellulose, and dodecanoic acid of 1:6:5, in a reactor equipped with a condensing device, nano-hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid are added to an ethanol solution with an ethanol mass concentration of 50wt%, heated under reflux at 95°C for 4h, and after the end, cooled to room temperature. The reaction solution is filtered by a centrifuge to remove water and ethanol to obtain a solid-phase substance, and the solid-phase substance is washed with pure water and dried to obtain modified nano-hydroxyapatite.

[0034] The preparation process of the montmorillonite cyclodextrin complex is as follows:

[0035] (1) According to the solid-liquid ratio of montmorillonite to acidic solution of 1g:18mL, montmorillonite is dispersed in 1.5mol / L hydrochloric acid solution, treated in an environment of 80°C for 5h, discharged, washed with pure water to neutrality, transferred to a tubular furnace, and calcined at 500°C for 1h to obtain calcined montmorillonite; after passing the calcined montmorillonite through a 400-mesh sieve, according to the mass ratio of calcined montmorillonite to sodium dodecylbenzenesulfonate of 1:2, the calcined montmorillonite is dispersed in pure water, and then sodium dodecylbenzenesulfonate is added, and the pH is adjusted to 1 with 0.1mol / L hydrochloric acid solution, stirred at room temperature for 5h, and after standing, the solid-phase substance is collected, washed and dried to obtain modified montmorillonite;

[0036] (2) According to the mass ratio of β-cyclodextrin to 2,3-epoxypropyltrimethylammonium chloride of 1:0.2, β-cyclodextrin is dissolved in an aqueous sodium hydroxide solution with a concentration of 0.15mol / L, and then 2,3-epoxypropyltrimethylammonium chloride is added, and heated and stirred at 45°C for 2h, discharged, washed with pure water to neutrality, and dried to obtain β-cyclodextrin cationic derivative;

[0037] (3) According to the mass ratio of modified montmorillonite to β-cyclodextrin cationic derivative of 1:24, the modified montmorillonite in step (1) and the β-cyclodextrin cationic derivative in step (2) are added to water, shaken at room temperature for 5h, and centrifuged to obtain a montmorillonite cyclodextrin complex.

[0038] The preparation method of the above high-performance low-carbon concrete additive is as follows:

[0039] Weigh each raw material according to the weight ratio. After mixing the modified nano-hydroxyapatite, fly ash, slag, and montmorillonite cyclodextrin complex evenly, then add a polycarboxylate superplasticizer with a water reduction rate of 30%, and mix evenly to obtain the product.

[0040] A kind of low-carbon concrete, which is composed of the following raw materials in parts by weight: 5 parts of the above additive, 93 parts of cement, 135 parts of water, 165 parts of silica fume, 70 parts of metakaolin, 680 parts of manufactured sand, and 950 parts of crushed stone.

[0041] Example 2

[0042] A high-performance low-carbon concrete additive, which is composed of the following raw materials in parts by weight: 70 parts of polycarboxylate superplasticizer (with a water reduction rate of 30%), 5 parts of modified nano-hydroxyapatite, 8 parts of fly ash, 20 parts of slag, and 9 parts of montmorillonite cyclodextrin complex.

[0043] Among them, the preparation process of the modified nano-hydroxyapatite is as follows:

[0044] According to the mass ratio of nano-hydroxyapatite, carboxymethyl cellulose, and dodecanoic acid of 1:4:3, in a reactor equipped with a condensing device, add nano-hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid to an ethanol solution with an ethanol mass concentration of 55wt%, heat and reflux at 90°C for 4.5h. After completion, cool to room temperature. The reaction solution is filtered by a centrifuge to remove water and ethanol to obtain a solid phase substance. The solid phase substance is washed with pure water and dried to obtain modified nano-hydroxyapatite.

[0045] The preparation process of the montmorillonite cyclodextrin complex is as follows:

[0046] (1) According to the solid-liquid ratio of montmorillonite to acidic solution of 1g:20mL, disperse montmorillonite in 1mol / L hydrochloric acid solution, treat it in an environment of 80°C for 5h, discharge the material, wash it with pure water until neutral, transfer it to a tubular furnace, and calcine it at 550°C for 0.8h to obtain calcined montmorillonite; after passing the calcined montmorillonite through a 400-mesh sieve, according to the mass ratio of calcined montmorillonite to sodium dodecylbenzenesulfonate of 1:1.5, disperse the calcined montmorillonite in pure water, then add sodium dodecylbenzenesulfonate, adjust the pH to 1 with 0.1mol / L hydrochloric acid solution, stir at room temperature for 5h, stand still, collect the solid phase substance, wash and dry it to obtain modified montmorillonite;

[0047] (2) Dissolve β-cyclodextrin in an aqueous sodium hydroxide solution with a concentration of 0.1 mol / L according to the mass ratio of β-cyclodextrin to 2,3-epoxypropyltrimethylammonium chloride of 1:0.1. Then add 2,3-epoxypropyltrimethylammonium chloride and heat and stir the reaction at 50 °C for 1.2 h. Discharge the product, wash it with pure water until neutral, and obtain the β-cyclodextrin cationic derivative after drying.

[0048] (3) Add the modified montmorillonite in step (1) and the β-cyclodextrin cationic derivative in step (2) to water according to the mass ratio of modified montmorillonite to β-cyclodextrin cationic derivative of 1:20, and shake and process at room temperature for 5 h. Obtain the montmorillonite cyclodextrin complex by centrifugation.

[0049] The preparation method of the above low-carbon concrete additive is as follows:

[0050] Weigh each raw material according to the weight ratio. After mixing the modified nano-hydroxyapatite, fly ash, slag, and montmorillonite cyclodextrin complex evenly, add a polycarboxylate superplasticizer with a water reduction rate of 30% and mix evenly to obtain the product.

[0051] A low-carbon concrete is composed of the following raw materials in parts by weight: 4 parts of the above additive, 95 parts of cement, 130 parts of water, 150 parts of silica fume, 80 parts of metakaolin, 650 parts of manufactured sand, and 900 parts of crushed stone.

[0052] Example 3

[0053] A high-performance low-carbon concrete additive is composed of the following raw materials in parts by weight: 80 parts of a polycarboxylate superplasticizer (with a water reduction rate of 30%), 10 parts of modified nano-hydroxyapatite, 15 parts of fly ash, 30 parts of slag, and 14 parts of montmorillonite cyclodextrin complex.

[0054] Among them, the preparation process of the modified nano-hydroxyapatite is as follows:

[0055] According to the mass ratio of nano-hydroxyapatite, carboxymethyl cellulose, and dodecanoic acid of 1:7:8, in a reactor equipped with a condensing device, add nano-hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid to an ethanol solution with an ethanol mass concentration of 40 wt%, heat and reflux at 100 °C for 4.5 h. After completion, cool to room temperature. The reaction solution is filtered by a centrifuge to remove water and ethanol to obtain a solid phase substance. Wash the solid phase substance with pure water and obtain the modified nano-hydroxyapatite after drying.

[0056] The preparation process of the montmorillonite cyclodextrin complex is as follows:

[0057] (1) Dispersed montmorillonite in 2 mol / L hydrochloric acid solution according to the solid-liquid ratio of montmorillonite to acidic solution of 1 g: 15 mL, treated it in an environment of 80 °C for 5 h, discharged the material, washed it with pure water until neutral, transferred it to a tubular furnace, and calcined it at 460 °C for 1.5 h to obtain calcined montmorillonite; after passing the calcined montmorillonite through a 400-mesh sieve, dispersed the calcined montmorillonite in pure water according to the mass ratio of calcined montmorillonite to sodium dodecylbenzenesulfonate of 1: 2.5, then added sodium dodecylbenzenesulfonate, adjusted the pH to 1 with 0.1 mol / L hydrochloric acid solution, stirred it at room temperature for 5 h, collected the solid phase material after standing, washed and dried it to obtain modified montmorillonite;

[0058] (2) Dissolved β-cyclodextrin in an aqueous sodium hydroxide solution according to the mass ratio of β-cyclodextrin to 2,3-epoxypropyltrimethylammonium chloride of 1: 0.3, the concentration of the aqueous sodium hydroxide solution was 0.2 mol / L, then added 2,3-epoxypropyltrimethylammonium chloride, heated and stirred the reaction at 40 °C for 2.5 h, discharged the material, washed it with pure water until neutral, and dried it to obtain β-cyclodextrin cationic derivative;

[0059] (3) Added the modified montmorillonite in step (1) and the β-cyclodextrin cationic derivative in step (2) to water according to the mass ratio of modified montmorillonite to β-cyclodextrin cationic derivative of 1: 28, oscillated and treated it at room temperature for 5 h, and centrifuged to obtain montmorillonite cyclodextrin complex.

[0060] The preparation method of the above high-performance low-carbon concrete additive is as follows:

[0061] Weighed each raw material according to the weight ratio, mixed the modified nano-hydroxyapatite, fly ash, slag, and montmorillonite cyclodextrin complex evenly, and then added a polycarboxylate superplasticizer with a water reduction rate of 30%, and mixed evenly to obtain it.

[0062] A high-performance low-carbon concrete, which is composed of the following raw materials in parts by weight: 7 parts of the above additive, 80 parts of cement, 140 parts of water, 180 parts of silica fume, 100 parts of metakaolin, 700 parts of manufactured sand, and 1000 parts of crushed stone.

[0063] 2. Comparative examples

[0064] Comparative example 1

[0065] The difference between comparative example 1 and example 1 is that:

[0066] The high-performance low-carbon concrete additive was not added, and the amount of cement in the concrete was 160 parts, and the rest was the same as that in example 1.

[0067] Comparative example 2

[0068] The difference between Comparative Example 2 and Example 1 is as follows:

[0069] Nano-hydroxyapatite is used to replace the modified nano-hydroxyapatite, and the rest is the same as in Example 1.

[0070] Comparative Example 3

[0071] The difference between Comparative Example 3 and Example 1 is as follows:

[0072] The additive is composed of the following raw materials in parts by weight: 72 parts of polycarboxylate superplasticizer, 1 part of nano-hydroxyapatite, 6 parts of carboxymethyl cellulose, 11 parts of fly ash, 23 parts of slag, and 10 parts of montmorillonite cyclodextrin complex. The rest is the same as in Example 1.

[0073] Comparative Example 4

[0074] The difference between Comparative Example 4 and Example 1 is as follows: The additive is composed of the following raw materials in parts by weight: 72 parts of polycarboxylate superplasticizer (water reduction rate is 30%), 9 parts of modified nano-hydroxyapatite, 11 parts of fly ash, 23 parts of slag, 9.6 parts of β-cyclodextrin, and 0.4 part of montmorillonite. The rest is the same as in Example 1.

[0075] 3. Test Example

[0076] Test Example 1

[0077] Referring to GB / T50081-2019 Standard for Test Methods of Physical and Mechanical Properties of Concrete, the compressive strengths of the concrete prepared in Examples 1-3 and Comparative Examples 1-4 at each age were measured, and the results are shown in Table 1. Among them, the cement reduction amount is calculated according to the reduction amount of the cement dosage in the groups of Examples 1-3 relative to the cement dosage in Comparative Example 1, and the cement reduction rate = (cement dosage in Comparative Example 1 - cement dosage) / cement dosage in Comparative Example 1 × 100%.

[0078] Table 1

[0079]

[0080] It can be seen from observing Table 1 that the concrete obtained in Examples 1-3 has excellent compressive strength. Moreover, after using the low-carbon concrete additive of the present invention, there is no obvious difference in the technical effects of the cement reduction rate of 40% and 50%.

[0081] Compared with Comparative Example 1 without adding the low-carbon concrete additive of the present invention and with a cement reduction rate of 0%, the concrete obtained in Examples 1-3 still has a relatively high compressive strength when the cement dosage is reduced by 40%-50%. This result shows that after adding the low-carbon concrete additive of the present invention, it is possible to reduce the cement dosage while also improving the compressive strength of the concrete.

[0082] Compared with Examples 1-3, in Comparative Example 2, nano-hydroxyapatite was used to replace the modified nano-hydroxyapatite, and in Comparative Example 3, nano-hydroxyapatite and carboxymethyl cellulose were added to the additive. The above adjustments all caused a decrease in the compressive strength of the resulting concrete. This result shows that the modified nano-hydroxyapatite can improve the compressive strength of the resulting concrete.

[0083] Further analysis shows that the surface of the modified nano-hydroxyapatite of the present invention is grafted with a long-chain alkyl structure, which enhances the bonding force between the nano-hydroxyapatite and the cement matrix, thereby improving the mechanical properties of the concrete.

[0084] Test Example 2

[0085] Referring to GB / T50080-2016 "Standard Test Method for Properties of Ordinary Concrete Mixtures", the fluidity of the concrete prepared in Examples 1-3 and Comparative Examples 1-4 was detected, and the results are shown in Table 2.

[0086] Table 2

[0087]

[0088] It can be seen from observing Table 2 that the initial fluidity of the concrete obtained in Examples 1-3 of the present invention is significantly larger, the slump retention performance is significantly better, and it still has a high fluidity after 1 h.

[0089] Compared with Examples 1-3, the fluidity of the concrete obtained in Comparative Example 4 decreased significantly, while in Comparative Example 4, β-cyclodextrin and montmorillonite were used to replace the montmorillonite cyclodextrin complex. This result shows that the montmorillonite cyclodextrin complex can improve the fluidity of the resulting concrete.

[0090] Further analysis shows that after the calcined montmorillonite is activated by the surfactant sodium dodecylbenzenesulfonate, the surface shows a negative charge, and it can adsorb and bind the cationic β-cyclodextrin derivative through electrostatic action and porous structure, thereby improving the dispersion and suspension state of cement particles in the concrete, and thus improving the fluidity of the concrete.

[0091] Test Example 3

[0092] Referring to GB / T749-2008 "Test Method for Resistance of Cement to Sulfate Attack", the resistance of the concrete obtained in Examples 1-3 to sulfate attack and seawater attack was detected, and the results are shown in Table 3.

[0093] Table 3

[0094]

[0095] It can be seen from observing Table 3 that the concrete obtained in Examples 1-3 has excellent resistance to sulfate attack and seawater attack.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. The basic principles and main features of the present invention have been described in the above with specific implementation schemes. On the basis of the present invention, some modifications or replacements can be made, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of protection required by the present invention.

Claims

1. A high-performance low-carbon concrete additive, characterized in that, It comprises the following raw materials in parts by weight: 70 - 80 parts of water - reducing agent, 5 - 10 parts of modified nano - hydroxyapatite, 8 - 15 parts of fly ash, 20 - 30 parts of slag, 9 - 14 parts of montmorillonite - cyclodextrin complex; The preparation process of the modified nano - hydroxyapatite is as follows: Nano - hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid are added to an ethanol solution for heating and reflux reaction. After the reaction solution is removed of the solvent, washed with water, and dried, the modified nano - hydroxyapatite is obtained; the saturated fatty acid is dodecanoic acid; The preparation process of the montmorillonite - cyclodextrin complex is as follows: (1) Montmorillonite is treated with an acidic solution and calcined to obtain calcined montmorillonite; the calcined montmorillonite is activated with a surfactant to obtain modified montmorillonite; (2) β - cyclodextrin is dissolved in an aqueous solution of sodium hydroxide, 2,3 - epoxypropyltrimethylammonium chloride is added, and the mixture is heated and stirred for reaction. After discharging, it is washed and dried to obtain β - cyclodextrin cationic derivative; (3) The modified montmorillonite obtained in step (1) and the β - cyclodextrin cationic derivative obtained in step (2) are added to water, and the mixture is shaken at room temperature and then centrifuged to obtain the montmorillonite - cyclodextrin complex.

2. The high-performance low-carbon concrete additive according to claim 1, wherein The mass ratio of the nano - hydroxyapatite, carboxymethyl cellulose, and saturated fatty acid is 1:(4 - 7):(3 - 8).

3. The high-performance low-carbon concrete additive according to claim 1, wherein The mass concentration of ethanol in the ethanol solution is 40 - 55wt%; the time of the reflux reaction is 3.5 - 4.5h.

4. The high-performance low-carbon concrete additive according to claim 1, characterized in that, In step (1), the solid - liquid ratio of the montmorillonite to the acidic solution is 1g:(15 - 20)mL, and the acidic solution is a hydrochloric acid solution with a concentration of 1 - 2mol / L; the calcination temperature is 460 - 550°C, and the time is 0.8 - 1.5h; the mass ratio of the calcined montmorillonite to the surfactant is 1:(1.5 - 2.5), and the surfactant is sodium dodecylbenzenesulfonate.

5. The high-performance low-carbon concrete additive according to claim 1, wherein In step (2), the mass ratio of the β - cyclodextrin to the 2,3 - epoxypropyltrimethylammonium chloride is 1:(0.1 - 0.3); the concentration of the aqueous solution of sodium hydroxide is 0.1 - 0.2mol / L; the temperature of the heating and stirring is 40 - 50°C, and the time is 1.2 - 2.5h; in step (3), the mass ratio of the modified montmorillonite to the β - cyclodextrin cationic derivative is 1:(20 - 28).

6. The high-performance low-carbon concrete additive according to claim 1, wherein The water - reducing agent is a polycarboxylic high - performance water - reducing agent with a water - reducing rate of 30%.

7. The preparation method of the high-performance low-carbon concrete additive according to claim 1, characterized in that It comprises the following steps: Weigh each raw material according to the weight - part ratio. After uniformly mixing the modified nano - hydroxyapatite, fly ash, slag, and montmorillonite - cyclodextrin complex, then add the water - reducing agent and mix uniformly to obtain the product.

8. The application of the high-performance low-carbon concrete additive according to claim 1, characterized in that, Application in the preparation of high - performance low - carbon concrete.

9. The application of the high-performance low-carbon concrete additive according to claim 8, wherein The low - carbon concrete is composed of the following raw materials in parts by weight: 4 - 7 parts of low - carbon concrete additive, 80 - 95 parts of cement, 130 - 140 parts of water, 150 - 180 parts of silica fume, 80 - 100 parts of metakaolin, 650 - 700 parts of manufactured sand, 900 - 1000 parts of crushed stone.

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