Composite concrete antibacterial agent, antibacterial concrete and preparation method of antibacterial concrete

Abstract

The invention provides a composite concrete antibacterial agent, antibacterial concrete and a preparation method thereof, and belongs to the technical field of building materials, the composite concrete antibacterial agent comprises hydroxypropyl-beta-cyclodextrin and an antibacterial compound included in the hydroxypropyl-beta-cyclodextrin, and the antibacterial compound is cinnamyl aldehyde or carvacrol; the composite concrete antibacterial agent is prepared from a cinnamyl aldehyde / hydroxypropyl-beta-cyclodextrin inclusion compound and a carvacrol / hydroxypropyl-beta-cyclodextrin inclusion compound. The structure of the inclusion compound solves the problems that cinnamyl aldehyde and carvacrol are difficult to dissolve in water, easy to oxidize, easy to volatilize and the like; and along with the increase of the water solubility of the corresponding clathrate, the release speed is greatly reduced, and the oxidation resistance is enhanced, so that the effective concentration required by concrete antibiosis can be achieved, and the antibacterial effect can be durably and stably exerted.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to a composite concrete antibacterial agent, antibacterial concrete and a preparation method thereof. Background Art

[0002] Harmful microorganisms such as bacteria and fungi are everywhere. They can be suspended in the air or attached to the surfaces and interiors of various objects. The presence and reproduction of bacteria and fungi in concrete buildings not only affect the appearance of the buildings, damage the internal structure of the concrete, shorten its service life, but also seriously affect people's living comfort and threaten human health. Therefore, with the increasing prevalence of bacterial and fungal infections, it is very necessary to study and improve the antibacterial properties of concrete materials to ensure the functions of concrete materials and improve the comfort of building use.

[0003] Currently, the antibacterial methods of building materials are as follows: Inorganic antibacterial agents are mainly metal oxides and some metal ions, such as silver ions, copper ions and zinc ions. Metal oxides mainly play a bactericidal role under the action of ultraviolet rays. Metal ions have the effect of destroying the organizational structure of microbial cells or inhibiting the growth and reproduction of bacteria. Usually, a suitable carrier is required, and they are prone to discoloration, affecting the aesthetics of products. Organic antibacterial agents have broad-spectrum and high-efficiency bactericidal capabilities, wide sources, simple processing processes and low costs, such as quaternary ammonium salts. It can affect the metabolism of microorganisms, destroy cell functions and inhibit the reproduction of microorganisms. However, most organic antibacterial agents have low bioavailability, poor solubility and high toxicity. Natural antibacterial agents are extracted from plants, such as antibacterial agents like eugenol, carvacrol, cinnamaldehyde and curcumin, which can avoid some potential risks brought by organic antibacterial agents. However, most natural antibacterial agents have defects such as poor water solubility, fast volatilization and low stability, thus reducing their antibacterial performance during use. Summary of the Invention

[0004] In view of the technical problems existing in the background art, the present application provides a composite concrete antibacterial agent, antibacterial concrete and a preparation method thereof, aiming to solve the technical problems that natural antibacterial agents have defects such as poor water solubility, fast volatilization and low stability, which reduce their antibacterial performance during use.

[0005] In a first aspect, an embodiment of the present application provides a composite concrete antibacterial agent, which includes hydroxypropyl-β-cyclodextrin and an antibacterial compound included in the hydroxypropyl-β-cyclodextrin. The antibacterial compound is cinnamaldehyde or carvacrol; the composite concrete antibacterial agent includes cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex.

[0006] In some embodiments, the mass ratio of cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex to carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex in the composite concrete antibacterial agent is 1:(0.6~1.3).

[0007] In a second aspect, an embodiment of the present application provides a method for preparing a composite concrete antibacterial agent, which includes the following steps: Disperse hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin dispersion; Disperse the antibacterial compound in absolute ethanol to obtain an antibacterial compound dispersion, and the antibacterial compound is cinnamaldehyde or carvacrol; Drop the antibacterial compound dispersion into the hydroxypropyl-β-cyclodextrin dispersion, stir, refrigerate, and then perform microfiltration. After freeze-drying the filtrate, an antibacterial compound / hydroxypropyl-β-cyclodextrin inclusion complex is obtained; When cinnamaldehyde is included in the hydroxypropyl-β-cyclodextrin, a cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. When carvacrol is included in the hydroxypropyl-β-cyclodextrin, a carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. Mix the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex to obtain a composite concrete antibacterial agent.

[0008] In some embodiments, the mass ratio of hydroxypropyl-β-cyclodextrin to deionized water in the hydroxypropyl-β-cyclodextrin dispersion is (16~20):100. In the antibacterial compound dispersion, the mass ratio of the antibacterial compound to absolute ethanol is (1.2~1.6):(7.0~8.5).

[0009] In a third aspect, an embodiment of the present application provides an antibacterial concrete, which includes 250~310 parts by mass of cement, 60~80 parts by mass of fly ash, 50~70 parts by mass of slag powder, 1000~1100 parts by mass of coarse aggregate, 700~800 parts by mass of fine aggregate, 5.4~6.9 parts by mass of admixture, 1.5~2.3 parts by mass of composite concrete antibacterial agent, and 150~170 parts by mass of water.

[0010] In some embodiments, the admixture includes water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early-strength aid, and defoamer, and their mass ratio is (3.8~4.1):1:(0.25~0.29):(0.24~0.28):(1.4~1.7):(0.18~0.22).

[0011] In some embodiments, the early-strength aid is one or more of calcium formate, sodium sulfate, triethanolamine, and calcium chloride.

[0012] In some embodiments, the defoamer is a polyether defoamer.

[0013] In some embodiments, the fly ash is Class II fly ash with a specific surface area of 310 - 350 m 2 / kg and a residue on a 325 - mesh sieve of 13% - 25%.

[0014] In some embodiments, the granulated blast - furnace slag powder has a specific surface area of 400 - 450 m 2 / kg, a residue on a 325 - mesh sieve of 7% - 9%, and an activity index of 95%.

[0015] In some embodiments, the coarse aggregate has a continuous gradation of 5 - 25 mm, a crushing value of ≤4%, a mud content of ≤0.3%, and a flaky and elongated particle content of 0.6% - 0.8%; the fineness modulus of the fine aggregate is 2.4 - 2.8.

[0016] Fourthly, the embodiments of the present application provide a preparation method of antibacterial concrete, including the following steps: mixing cement, fly ash, granulated blast - furnace slag powder, coarse aggregate, and fine aggregate evenly to obtain a dry - mixed material; dissolving polycarboxylate water - reducing agent, polycarboxylate slump - retaining agent, viscosity - reducing agent, early - strength auxiliary agent, and defoaming agent sufficiently in water and dispersing them evenly to obtain an admixture; dispersing the admixture and a composite concrete antibacterial agent evenly in water to obtain a mixed liquid; continuously stirring the dry - mixed material and simultaneously adding the mixed liquid continuously for multiple times and mixing evenly to prepare the antibacterial concrete.

[0017] Different from the prior - art solutions, the beneficial effects of the present application include: 1. The present application uses an inclusion compound prepared from natural antibacterial agents cinnamaldehyde, carvacrol, and hydroxypropyl - β - cyclodextrin as the concrete antibacterial agent. Cinnamaldehyde and carvacrol have strong inhibitory abilities against fungi, hyphae, spores, and bacteria. Cinnamaldehyde and carvacrol can bind to factors such as hormones and proteins in microbial cells, affecting normal cell division; affecting cell energy supply and the synthesis of biological membranes; enhancing the permeability of the microbial cell membrane, causing the leakage of intracellular substances and leading to the death of bacteria. When used in concrete, it will play a role in preventing the growth and reproduction of various microorganisms in concrete, killing bacteria, and improving the ability of concrete to resist microbial erosion.

[0018] In this application, by virtue of the "hydrophilic outside and hydrophobic inside" hollow ring structure of hydroxypropyl-β-cyclodextrin, with intermolecular hydrogen bonds as an important driving force, the polar enal group of cinnamaldehyde is located at the ring opening end of hydroxypropyl-β-cyclodextrin, forming intermolecular hydrogen bonds with its hydroxyl groups. The hydrophobic phenyl group inserts into the hydrophobic cavity of hydroxypropyl-β-cyclodextrin to produce van der Waals force interactions, thus forming a stable cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex. Similarly, the polar phenolic hydroxyl group of carvacrol is located at the ring opening end of hydroxypropyl-β-cyclodextrin, forming intermolecular hydrogen bonds with its hydroxyl groups, and the hydrophobic phenyl group inserts into the hydrophobic cavity of hydroxypropyl-β-cyclodextrin, forming a stable carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex. The structure of the inclusion complex not only solves the problems of poor water solubility, easy oxidation, and easy volatilization of cinnamaldehyde and carvacrol, creating favorable conditions for their application in concrete materials; but also, with the increase in the water solubility of the corresponding inclusion complex, a significant decrease in the release rate, and an enhancement of the antioxidant capacity, it can reach the effective concentration required for concrete antibacterial, and can exert an antibacterial effect persistently and stably. Due to the tiny pores and closed space in the concrete material structure, the sustained-release and antioxidant capacities of the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex will be further improved, thereby ensuring that the above inclusion complexes can play an antibacterial role effectively in concrete for a long time. Designing the combined use of the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex can enhance their sterilization ability and broaden the sterilization spectrum through synergistic effects. It can not only effectively reduce the minimum inhibitory concentration but also avoid the generation of microbial drug resistance.

[0019] 2. When hydroxypropyl-β-cyclodextrin is used as an inclusion material in concrete, on the one hand, it can solve the problems of poor water solubility, easy oxidation, and easy volatilization of cinnamaldehyde and carvacrol; on the other hand, it can slow down the hydration reaction of cement, prolong the setting time of concrete, thereby improving the fluidity of concrete. It can also penetrate into the pores of concrete to form a dense colloidal layer, thereby reducing the porosity of concrete and improving the compactness and waterproofness of concrete by filling small holes and capillary pores. Further strengthening the sustained-release and antioxidant capacities of the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex can enhance the persistence of the antibacterial performance of concrete.

[0020] 3. This application uses an ultra-early-strength polycarboxylate water reducer. With the help of its ultra-long side-chain structure in the molecular structure, it can effectively accelerate the cement hydration reaction and prevent the emergence of serious setting retardation phenomenon in concrete caused by the multi-hydroxyl structure of hydroxypropyl-β-cyclodextrin when the dosage of hydroxypropyl-β-cyclodextrin inclusion complex is excessive. Under alkaline conditions, the polycarboxylate slump retention agent releases carboxyl groups through the hydrolysis of esters, which can provide sufficient construction time for the concrete. A viscosity reducer with a small molecular weight and low viscosity is added to the concrete, which can effectively improve the viscosity of the concrete through lubrication. A polyether defoamer is used as the concrete defoamer, which can eliminate the air bubbles in the concrete to the greatest extent, increase the compactness of the concrete and thus improve the strength. In addition, calcium formate is used as an early-strength auxiliary agent to further offset the adverse effects brought by the setting retardation effect of hydroxypropyl-β-cyclodextrin, and at the same time play an auxiliary role in anti-corrosion and antibacterial.

[0021] 4. This application uses fly ash and slag powder. The particle size of the slag powder is between that of cement and fly ash. The combination of the three further improves the packing density, enhances the strength and impermeability of the concrete, improves the durability of the concrete, reduces the heat of hydration of the concrete, and reduces the temperature rise of the concrete, thereby reducing the expansion and cracking of the concrete.

[0022] The above description is only an overview of the technical solution of this application. In order to be able to more clearly understand the technical means of this application, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specific embodiments of this application are specifically given. Specific Embodiments

[0023] The embodiments of the technical solution of this application will be described in detail below. The following embodiments are only used to more clearly illustrate the technical solution of this application, so they are only examples and cannot be used to limit the protection scope of this application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and any variations thereof are intended to cover non-exclusive inclusion.

[0025] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0026] References to "embodiments" in this specification mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0028] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0029] Currently, the antibacterial methods of building materials: Inorganic antibacterial agents are mainly metal oxides and some metal ions, such as silver ions, copper ions, and zinc ions. Metal oxides mainly play a bactericidal role under the action of ultraviolet light. Metal ions have the effect of destroying the organizational structure of microbial cells or inhibiting the growth and reproduction of bacteria. Usually, a suitable carrier is required, and they are prone to discoloration, affecting the aesthetics of the products. Organic antibacterial agents have broad-spectrum and high-efficiency bactericidal capabilities, wide sources, simple processing processes, and low costs, such as quaternary ammonium salts. It can affect the metabolism of microorganisms, destroy cell functions, and inhibit the reproduction of microorganisms. However, most organic antibacterial agents have low bioavailability, poor solubility, and high toxicity.

[0030] In order to solve the technical problems that natural antibacterial agents have poor water solubility, fast volatilization, low stability, etc., and reduce their antibacterial performance during use, the present application provides a composite concrete antibacterial agent, antibacterial concrete, and its preparation method. The concrete in the present application has broad-spectrum antibacterial properties, is not prone to drug resistance during the entire life cycle of microorganisms, has good durability against microbial erosion, is environmentally friendly, and can effectively improve the service life of buildings.

[0031] In a first aspect, an embodiment of the present application provides a composite concrete antibacterial agent. Using hydroxypropyl-β-cyclodextrin as a carrier, an antibacterial compound is included in the hydroxypropyl-β-cyclodextrin to form an antibacterial compound / hydroxypropyl-β-cyclodextrin inclusion complex. The antibacterial compound is cinnamaldehyde or carvacrol; the composite concrete antibacterial agent includes a cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and a carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex.

[0032] In some embodiments, the mass ratio of cinnamaldehyde to carvacrol in the composite concrete antibacterial agent is 1:(0.6 - 1.3) In the technical solution of the embodiment of the present application, cinnamaldehyde and carvacrol respectively form cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex with hydroxypropyl-β-cyclodextrin. The two kinds of cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex are designed to be used in combination. Through the synergistic effect of carvacrol and cinnamaldehyde, the sterilization ability can be enhanced, the sterilization spectrum can be broadened, not only can the minimum inhibitory concentration be effectively reduced, but also the generation of microbial drug resistance can be avoided.

[0033] Second, the embodiment of the present application provides a preparation method of a composite concrete antibacterial agent, which includes the following steps: Disperse hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin dispersion; Disperse the antibacterial compound in absolute ethanol to obtain an antibacterial compound dispersion, and the antibacterial compound is cinnamaldehyde or carvacrol; Drop the antibacterial compound dispersion into the hydroxypropyl-β-cyclodextrin dispersion, stir, refrigerate and then carry out microfiltration, and freeze-dry the filtrate to obtain an antibacterial compound / hydroxypropyl-β-cyclodextrin inclusion complex; When cinnamaldehyde is included in the hydroxypropyl-β-cyclodextrin, a cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. When carvacrol is included in the hydroxypropyl-β-cyclodextrin, a carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. Mix the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex to obtain a composite concrete antibacterial agent.

[0034] In some embodiments, the mass ratio of hydroxypropyl-β-cyclodextrin to deionized water in the hydroxypropyl-β-cyclodextrin dispersion is (16-20):100, and in the antibacterial compound dispersion, the mass ratio of the antibacterial compound to absolute ethanol is (1.2-1.6):(7.0-8.5).

[0035] In the technical solution of the embodiment of the present application, cinnamaldehyde is the main component of cinnamon essential oil produced by aromatic cinnamon plants. It is non-toxic or low-toxic to the human body and has antibacterial properties against pathogenic bacteria such as Bacillus cereus, Escherichia coli, molds and Listeria monocytogenes, and has a better inhibitory effect on fungi. Cinnamaldehyde mainly plays a bactericidal role by destroying the microbial cell wall, penetrating into the microbial cell, and destroying cell organelles. And the application of cinnamaldehyde is not affected by the pH value. It has strong bactericidal and disinfection functions for acidic or alkaline substances and can be widely used for anti-corrosion and anti-mildew. However, cinnamaldehyde is poorly soluble in water, highly volatile, and easily oxidized in the air and loses its antibacterial activity.

[0036] Carvacrol is widely present in the essential oils of many aromatic plants and is an aromatic phenolic monoterpene compound. Carvacrol has the characteristics of antioxidant, high lipid solubility, small molecular weight, easy to pass through cell membranes, and non-toxic to humans at low doses. It has good inhibitory effects on both Gram-negative bacteria and Gram-positive bacteria, and its antibacterial effect on Gram-positive bacteria is stronger than that on Gram-negative bacteria. It can effectively inhibit the growth of Escherichia coli, Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Enterobacter cloacae, etc. However, carvacrol has poor thermal stability, is volatile and almost insoluble in water.

[0037] Hydroxypropyl-β-cyclodextrin is a "truncated cone" molecule with a hollow ring structure, thus forming a special structure of "hydrophilic outside and hydrophobic inside", which endows it with many special properties. It can form inclusion compounds with a wide range of various guest molecules, such as complexes, organic molecules, inorganic ions, etc. through intermolecular interactions, thereby having functions such as shielding, active protection, controlled release, and solubilization for the guests. By using the special cavity structure of hydroxypropyl-β-cyclodextrin, cinnamaldehyde and carvacrol are respectively included in its cavity structure to form inclusion compounds, which can protect them from the influence of moisture, heat, light, oxygen or other extreme conditions, achieving the purposes of slow release, solubilization, anti-light, antioxidant, etc., thereby enhancing the antibacterial performance and durability for use in the concrete field.

[0038] In a third aspect, the embodiments of the present application provide an antibacterial concrete, which includes 250-310 parts by mass of cement, 60-80 parts by mass of fly ash, 50-70 parts by mass of slag powder, 1000-1100 parts by mass of coarse aggregate, 700-800 parts by mass of fine aggregate, 5.4-6.9 parts by mass of admixture, 1.5-2.3 parts by mass of a composite concrete antibacterial agent, and 150-170 parts by mass of water.

[0039] In the technical solution of the embodiments of the present application, the cement is Huaxin PO42.5 ordinary Portland cement with a 28-day strength of 47.6 MPa; the super-early-strength polycarboxylate water reducer is produced by Guangzhou Superplastic Building Materials Co., Ltd., model STP160UX, with a solid content of 40%; the polycarboxylate slump-retaining agent is produced by Huaxin Xijiesi Building Materials Technology Co., Ltd., model HXYJY-BT45, with a solid content of 45%; the viscosity reducer is produced by Nanjing Qicheng New Materials Co., Ltd., model 361; the defoamer is a polyether defoamer of Nippon Yushi Co., Ltd., model AFK-2.

[0040] In some embodiments, the admixture includes water, super-early-strength polycarboxylate water reducer, polycarboxylate slump-retaining agent, viscosity reducer, early-strength aid, and defoamer, and their mass ratio is (3.8-4.1):1:(0.25-0.29):(0.24-0.28):(1.4-1.7):(0.18-0.22).

[0041] In some embodiments, the early-strength aid is one or more of calcium formate, sodium sulfate, triethanolamine, and calcium chloride.

[0042] In the technical solution of the embodiment of the present application, in concrete, cinnamaldehyde / hydroxypropyl-β-cyclodextrin and carvacrol / hydroxypropyl-β-cyclodextrin must reach the minimum antibacterial concentration to achieve good antibacterial and bactericidal effects. Therefore, the dosage of the added hydroxypropyl-β-cyclodextrin inclusion complex is bound to be relatively large. However, there are many hydroxyl groups in the molecular structure of hydroxypropyl-β-cyclodextrin, and excessive addition will lead to the problem of slow cement hydration. Therefore, it is necessary to reduce the minimum antibacterial concentration of the above two inclusion complexes and solve the problem of concrete setting retardation at the same time. In addition, too much hydroxypropyl-β-cyclodextrin will cause the concrete to become sticky, affecting the construction effect, and it is also necessary to improve the problem of sticky concrete.

[0043] The present application uses an ultra-early-strength polycarboxylate water reducer. With the help of its ultra-long side-chain structure in the molecular structure, it effectively accelerates the cement hydration reaction and prevents the emergence of serious setting retardation of concrete caused by the multi-hydroxyl structure of hydroxypropyl-β-cyclodextrin when the dosage of hydroxypropyl-β-cyclodextrin inclusion complex is too much. Under alkaline conditions, the polycarboxylate slump-retaining agent releases carboxyl groups through the hydrolysis of esters, which can provide sufficient construction time for the concrete. A viscosity-reducing agent is added to the concrete. It has a small molecular weight and low viscosity, and can effectively improve the viscosity of the concrete through lubrication. A polyether defoaming agent is used as the concrete defoaming agent, which can eliminate the air bubbles in the concrete to the greatest extent, increase the compactness of the concrete and thus improve the strength. In addition, calcium formate is used as an early-strength auxiliary agent to further offset the adverse effects brought by the setting retardation effect of hydroxypropyl-β-cyclodextrin, and at the same time play an auxiliary role in anti-corrosion and antibacterial.

[0044] In some embodiments, the defoaming agent is a polyether defoaming agent.

[0045] In some embodiments, the fly ash is the second-class fly ash from Ezhou Power Plant, with a specific surface area of 310-350 m 2 / kg and a residue on a 325-mesh sieve of 13%-25%.

[0046] In some embodiments, the slag powder is WISCO S95 with a specific surface area of 400-450 m 2 / kg, a residue on a 325-mesh sieve of 7%-9%, and an activity index of 95%.

[0047] In some embodiments, the coarse aggregate has a continuous grading of 5-25 mm, a crushing value ≤ 4%, a mud content ≤ 0.3%, and a flake content of 0.6%-0.8%; the fineness modulus of the fine aggregate is 2.4-2.8.

[0048] Fourthly, an embodiment of the present application provides a preparation method of antibacterial concrete, which includes the following steps: mixing cement, fly ash, slag powder, coarse aggregate, and fine aggregate evenly to obtain a dry mixture; dissolving polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early strength promoter, and defoaming agent in water sufficiently and dispersing them evenly to obtain an admixture; dispersing the admixture and a composite concrete antibacterial agent evenly in water to obtain a mixture; continuously stirring the dry mixture, and simultaneously adding the mixture continuously for multiple times and mixing evenly to prepare the antibacterial concrete.

[0049] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation to the present application. For those without specific technologies or conditions noted in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product specifications. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0050] I. Preparation method Example 1 An antibacterial concrete, the composition of which is as follows by weight: 250 parts of cement, 60 parts of fly ash, 50 parts of slag powder, 1000 parts of coarse aggregate, 700 parts of fine aggregate, 5.4 parts of admixture, 1.5 parts of antibacterial agent, and 150 parts of water. Among them, the mass ratio of the antibacterial agents cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is 1:0.6; in the admixture, the mass ratio of water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early strength promoter, and defoaming agent is 3.8:1:0.25:0.24:1.4:0.18.

[0051] Among them, the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex are obtained according to the following preparation method: Weigh 18 parts of hydroxypropyl-β-cyclodextrin, dissolve it in 100 parts of deionized water, heat up and keep it at 50 °C under continuous stirring, dissolve 1.3 parts of cinnamaldehyde (1.5 parts of carvacrol) in 7.9 parts of absolute ethanol, and drop it evenly into the above-mentioned hydroxypropyl-β-cyclodextrin aqueous solution. The dropping is completed in 20 min, continue stirring for 5 h, then cool to room temperature, and refrigerate at 4 °C for 10 h, and filter through a 45 μm microporous filter membrane. The filtrate is freeze-dried and then eluted with 75.8 parts of acetone to remove the free cinnamaldehyde (carvacrol), and 24.7 parts (24.8 parts) of cinnamaldehyde / hydroxypropyl-β-cyclodextrin (carvacrol / hydroxypropyl-β-cyclodextrin) solid powder inclusion complex are obtained, and it is sieved through an 80-mesh sieve for standby.

[0052] Example 2 An antibacterial concrete, the composition of which is as follows by weight parts: 270 parts of cement, 65 parts of fly ash, 56 parts of slag powder, 1031 parts of coarse aggregate, 728 parts of fine aggregate, 6.0 parts of admixture, 1.7 parts of antibacterial agent, and 155 parts of water. Among them, the mass ratio of the antibacterial agents cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is 1:0.8, and the preparation method of the antibacterial agent is the same as that in Example 1; in the admixture, the mass ratio of water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early-strength aid, and defoamer is 3.8:1:0.27:0.25:1.4:0.21.

[0053] Example 3 An antibacterial concrete, the composition of which is as follows by weight parts: 290 parts of cement, 65 parts of fly ash, 56 parts of slag powder, 1100 parts of coarse aggregate, 766 parts of fine aggregate, 6.4 parts of admixture, 2.0 parts of antibacterial agent, and 164 parts of water. Among them, the mass ratio of the antibacterial agents cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is 1:1, and the preparation method of the antibacterial agent is the same as that in Example 1; in the admixture, the mass ratio of water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early-strength aid, and defoamer is 3.9:1:0.29:0.26:1.7:0.19.

[0054] Example 4 An antibacterial concrete, the composition of which is as follows by weight parts: 310 parts of cement, 80 parts of fly ash, 70 parts of slag powder, 1067 parts of coarse aggregate, 800 parts of fine aggregate, 6.9 parts of admixture, 1.5 parts of antibacterial agent, and 170 parts of water. Among them, the mass ratio of the antibacterial agents cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is 1:1.3, and the preparation method of the antibacterial agent is the same as that in Example 1; in the admixture, the mass ratio of water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early-strength aid, and defoamer is 4.1:1:0.26:0.28:1.6:0.22.

[0055] Example 5 An antibacterial concrete, the composition of which is as follows by weight parts: 270 parts of cement, 70 parts of fly ash, 60 parts of slag powder, 1031 parts of coarse aggregate, 728 parts of fine aggregate, 6.0 parts of admixture, 2.3 parts of antibacterial agent, and 155 parts of water. Among them, the mass ratio of the antibacterial agents cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is 1:1, and the preparation method of the antibacterial agent is the same as that in Example 1; in the admixture, the mass ratio of water, super-early-strength polycarboxylate water reducer, polycarboxylate slump retainer, viscosity reducer, early-strength aid, and defoamer is 3.8:1:0.27:0.25:1.4:0.21.

[0056] Comparative Example 1 Difference between this comparative example and Example 1: No antibacterial agent is added.

[0057] Comparative Example 2 Difference between this comparative example and Example 1: 1.5 parts of antibacterial agent, but the antibacterial agent is only cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex.

[0058] Comparative Example 3 Difference between this comparative example and Example 2: 2.3 parts of antibacterial agent, but the antibacterial agent is only carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex.

[0059] Comparative Example 4 Difference between this comparative example and Example 3: The super-early-strength polycarboxylate water reducer in the admixture is replaced with a common polycarboxylate water reducer.

[0060] Comparative Example 5 Difference between this comparative example and Example 3: No polycarboxylate slump-retaining agent is added to the admixture.

[0061] Comparative Example 6 Difference between this comparative example and Example 4: No viscosity-reducing agent is added to the admixture.

[0062] Comparative Example 7 Difference between this comparative example and Example 4: No early-strength aid is added to the admixture.

[0063] Comparative Example 8 Difference between this comparative example and Example 5: No defoaming agent is added to the admixture.

[0064] II. Test Methods 1. Test method for physical and mechanical properties of antibacterial concrete: According to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", test the pouring time, slump, and spread of antibacterial concrete.

[0065] 2. Test method for compressive strength of antibacterial concrete: Mold the concrete, select the test block size of 100mm×100mm×100mm, cure it under standard conditions, and measure its compressive strength.

[0066] 3. Test method for corrosion resistance of antibacterial concrete: Test the mass loss rate and compressive strength corrosion resistance coefficient of concrete test blocks according to the test method in the patent authorization announcement number CN115093185.

[0067] III. Analysis of Test Results of Each Example and Comparative Example Conduct physical and mechanical property tests, compressive strength tests, and corrosion resistance tests on the concrete prepared in each example and comparative example. The test results are shown in Table 1 below.

[0068] Table 1 Test Results of Concrete Properties Prepared in Each Example and Comparative Example

[0069] Comparing the data of Examples 1 to 5 in Table 1, it can be seen that within the scope of the claims, the compressive strength corrosion resistance coefficient shows an upward trend as the proportion of the antibacterial agent increases, while the mass loss rate of the concrete shows a gradually decreasing trend.

[0070] Comparing the data of Examples 1-2 and Comparative Examples 1-3 in Table 1, it can be seen that adding the antibacterial agent does not affect the slump and spread of the concrete; it can significantly improve the antibacterial performance of the concrete and reduce the mass loss caused by microbial erosion; the antibacterial agent inclusion material hydroxypropyl-β-cyclodextrin is beneficial to the formation of a denser crystal structure in the concrete and improves the 28d strength of the concrete; comparing the antibacterial effects of the compound and single use of cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion and thymol / hydroxypropyl-β-cyclodextrin inclusion shows that when the two inclusions are used in combination, the degree of decrease in the compressive strength corrosion resistance coefficient and the increase in the mass loss rate of the concrete both decrease, and the antibacterial effect is better.

[0071] Comparing the data of Example 3 and Comparative Examples 4-5 in Table 1, it can be seen that the ultra-early-strength polycarboxylate water reducer can accelerate the crystallization of Ca(OH) 2 and the formation of ettringite through its ultra-long side chain structure, improve the early strength of the antibacterial concrete, and reduce the adverse effect of hydroxypropyl-β-cyclodextrin on the early strength of the concrete; the polycarboxylate slump retaining agent is beneficial to extending the plasticity duration of the antibacterial concrete, avoiding the poor compaction of the concrete due to the decrease in fluidity, and then resulting in the decrease in the strength of the concrete at each age and the poor antibacterial effect.

[0072] Comparing the data of Example 4, Comparative Example 1, and Comparative Examples 6-7 in Table 1, it can be seen that the small molecule viscosity reducer shortens the slump time of the antibacterial concrete through lubrication, that is, improves the viscosity and fluidity of the concrete, makes the concrete fill more evenly and densely, effectively improves the strength of the concrete, thereby increasing the compressive strength and corrosion resistance coefficient and reducing the mass loss rate of the concrete.

[0073] Comparing the data of Example 5 and Comparative Example 8 in Table 1, it can be seen that the defoamer improves the compactness of the concrete by eliminating excess bubbles, improves the strength at each age, and then improves the antibacterial effect.

[0074] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same composition and the same function and effect as the technical idea within the scope of the technical solution of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various deformations that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A composite concrete antibacterial agent, characterized in that: It comprises hydroxypropyl-β-cyclodextrin and an antibacterial compound contained in the hydroxypropyl-β-cyclodextrin, wherein the antibacterial compound is cinnamaldehyde or carvacrol; the composite concrete antibacterial agent comprises cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion compound and carvacrol / hydroxypropyl-β-cyclodextrin inclusion compound.

2. A composite concrete antibacterial agent according to claim 1, characterized in that: The mass ratio of the cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex to the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex in the composite concrete antibacterial agent is 1:(0.6-1.3).

3. The method for preparing a composite concrete antibacterial agent according to claim 1 or 2, characterized in that: The steps include: dispersing hydroxypropyl-β-cyclodextrin in deionized water to obtain a hydroxypropyl-β-cyclodextrin dispersion; dispersing the antibacterial compound in anhydrous ethanol to obtain an antibacterial compound dispersion, wherein the antibacterial compound is cinnamaldehyde or carvacrol; The antibacterial compound dispersion is added dropwise to the hydroxypropyl-β-cyclodextrin dispersion, stirred, refrigerated, and then microfiltered, and the filtrate is freeze-dried to obtain an antibacterial compound / hydroxypropyl-β-cyclodextrin inclusion complex; When the cinnamaldehyde is included in the hydroxypropyl-β-cyclodextrin, a cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. When the carvacrol is included in the hydroxypropyl-β-cyclodextrin, a carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex is obtained. The cinnamaldehyde / hydroxypropyl-β-cyclodextrin inclusion complex and the carvacrol / hydroxypropyl-β-cyclodextrin inclusion complex are mixed to obtain a composite concrete antibacterial agent.

4. The method for preparing the composite concrete antibacterial agent according to claim 3, characterized in that: The mass ratio of hydroxypropyl-β-cyclodextrin to deionized water in the hydroxypropyl-β-cyclodextrin dispersion is (16-20):100, and the mass ratio of the antibacterial compound to anhydrous ethanol in the antibacterial compound dispersion is (1.2-1.6):(7.0-8.5). 5.An antibacterial concrete, characterized in that: The composition comprises, by weight, 250-310 parts of cement, 60-80 parts of fly ash, 50-70 parts of slag powder, 1000-1100 parts of coarse aggregate, 700-800 parts of fine aggregate, 5.4-6.9 parts of admixture, 1.5-2.3 parts of the composite concrete antibacterial agent according to claim 1 or 2, and 150-170 parts of water.

6. The antibacterial concrete according to claim 5, characterized in that: The admixture includes water, super early strength polycarboxylic acid water reducing agent, polycarboxylic acid slump retaining agent, viscosity reducer, early strength aid and defoaming agent, and the mass ratio thereof is (3.8-4.1):1:(0.25-0.29):(0.24-0.28):(1.4-1.7):(0.18-0.22).

7. The antibacterial concrete according to claim 6, characterized in that: The early strength aid is one or more of calcium formate, sodium sulfate, triethanolamine and calcium chloride.

8. The antibacterial concrete according to claim 6, characterized in that: The defoamer is a polyether defoamer.

9. The antibacterial concrete according to claim 5, characterized in that: The fly ash is Grade II fly ash with a specific surface area of ​​310-350m 2 / kg, 325 mesh sieve residue is 13-25%; the specific surface area of ​​the slag powder is 400-450m 2 / kg, 325 mesh residue is 7~9%, activity index is 95%; the coarse aggregate is 5~25mm continuous grading, crushing value ≤4%, mud content ≤0.3%, needle-like shape is 0.6~0.8%; the modulus coefficient of the fine aggregate is 2.4~2.

8.

10. A method for preparing antibacterial concrete according to any one of claims 5 to 9, characterized in that: The method comprises the following steps: mixing cement, fly ash, slag powder, coarse aggregate and fine aggregate uniformly to obtain a dry mix; fully dissolving a polycarboxylic acid water reducer, a polycarboxylic acid slump retaining agent, a viscosity reducer, an early strength aid and a defoaming agent in water and dispersing them uniformly to obtain an admixture; dispersing the admixture and a composite concrete antibacterial agent uniformly in water to obtain a mixed liquid; continuously stirring the dry mix and continuously adding the mixed liquid for multiple times to mix them uniformly to obtain the antibacterial concrete.

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