Compact, anti-crack and waterproof additive for concrete and preparation method of dense, anti-crack and waterproof additive

Abstract

The invention relates to a concrete compact anti-crack waterproof additive and a preparation method thereof, and belongs to the technical field of water resistance and crack resistance of concrete, and the concrete compact anti-crack waterproof additive is prepared from the following raw materials: 5-10 parts of polyferric sulfate, 3-8 parts of nanoscale modified chitin, 1-3 parts of anhydrous sodium sulfate and 60-100 parts of water. The concrete compact anti-crack waterproof additive prepared from the nanoscale modified chitin, the polyferric sulfate, the nanoscale modified chitin, the anhydrous sodium sulfate and the water according to a reasonable proportion is matched with ultrasonic dispersion and microwave modification, so that the concrete compact anti-crack waterproof additive has good advantages in strength, electric flux and tensile value indexes; the problem of non-uniform dispersion of a traditional additive is solved, the uniformity of the material is improved, the film-forming and crack-resisting performance of the material is enhanced, high sulfuric acid group content of polymeric ferric sulfate promotes crystallization densification, a synergistic effect is formed by the polymeric ferric sulfate and the coagulation accelerating effect of sodium sulfate, and shrinkage cracks are inhibited while the water-proof capability attenuation is resisted, the densification and water-proof duration is prolonged and the early strength is improved.

Description

Technical Field

[0001] This invention belongs to the field of concrete waterproofing and crack resistance technology, specifically relating to a concrete compaction crack-resistant and waterproofing additive and its preparation method. Background Technology

[0002] Waterproofing and crack resistance of concrete are key technologies to ensure the durability and safety of structures, and require comprehensive control from multiple aspects such as materials, design, construction and maintenance.

[0003] Currently, concrete engineering commonly uses single-function materials such as silicone waterproofing agents, polypropylene fibers, or expansion agents. Among them, silicone materials can only form a film on the surface and cannot fill the internal capillary pores. They are prone to aging and failure with long-term use. Although synthetic fibers can inhibit crack propagation, they will reduce the density of concrete, causing the chloride ion permeability to rise to over 1000°C, accelerating the corrosion of steel bars. Expansion agents are prone to causing later shrinkage rebound, significantly reducing the 28-day strength increase, and excessive use may induce cracking. Based on the above description, it is known that the long-term dense waterproofing performance is insufficient, and the crack resistance and early strength are inadequate. Summary of the Invention

[0004] The purpose of this invention is to provide a concrete compaction, crack resistance, and waterproofing additive and its preparation method in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] This invention provides a concrete compaction, crack resistance, and waterproofing additive. By weight, the raw materials for preparing the concrete compaction, crack resistance, and waterproofing additive include: 5-10 parts of polyferric sulfate, 3-8 parts of nano-modified chitosan, 1-3 parts of anhydrous sodium sulfate, and 60-100 parts of water. Among them, anhydrous sodium sulfate acts as a setting accelerator to adjust the early hydration rate of cement and achieve crack resistance enhancement.

[0007] As a further optimization of the present invention, the content of the sulfuric acid groups in the polyferric sulfate is ≥18%, which is used to promote the cement hydration reaction and form a dense crystalline structure.

[0008] As a further optimization of the present invention, the chitin is specifically nanoscale modified chitin.

[0009] As a further optimization of the present invention, the specific preparation method of the nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 20-30 minutes, with the stirring temperature controlled at 70-90℃; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) The pure nano-chitin is added to deionized water and initially dispersed by ultrasonic treatment; (v) Add surface modifiers and adjust the pH to the point that the particles have a net charge and the absolute value of the Zeta potential is >30mV to finally obtain a uniform suspension; (vi) use dynamic light scattering to screen the particle size of the nano-chitosan suspension, remove agglomerates with a particle size greater than 200nm by centrifugation, and obtain nano-scale chitosan with a particle size ≤200nm; (vii) use microwave-assisted modification to treat the nano-scale chitosan with a particle size ≤200nm to obtain nano-scale modified chitosan, wherein the surface is carboxymethylated to enhance dispersibility and improve its film-forming performance.

[0010] As a further optimization of the present invention, the raw materials for preparing nano-modified chitin, by weight, include: 3-6 parts chitin, 50-80 parts hydrochloric acid solution with a concentration of 60%, 50-80 parts sodium hydroxide solution with a concentration of 60%, 60-90 parts deionized water, and 7-16 parts surface modifier.

[0011] As a further optimization of the present invention, the raw materials for preparing the temperature-appropriate agent include: 6-8 parts paraffinic oil, 3-5 parts alkylphenol polyoxyethylene ether, 3-9 parts trimethylolpropane ester, 2-4 parts silane coupling agent, 3-5 parts silicone oil, 3-5 parts silicone oil emulsifier, and 6-8 parts water.

[0012] As a further optimization of the present invention, the specific preparation method of the temperature-adaptive agent is as follows: (i) heating paraffinic oil to a liquid state, adding alkylphenol polyoxyethylene ether, slowly adding water under high shear dispersion conditions, continuously stirring until the system is stable and forms a low-viscosity emulsion, controlling the temperature at 90°C, and obtaining a paraffinic oil emulsion; (ii) mixing trimethylolpropane ester with silicone oil, adding a silane coupling agent, and then mixing with a silicone oil emulsifier, and shearing it through a high-shear emulsifier until the particle size is uniform, and obtaining a composite emulsion; (iii) mixing the paraffinic oil emulsion with the composite emulsion, and shearing it until the system is completely stable, and obtaining a temperature-adaptive agent.

[0013] This invention also provides a method for preparing a concrete compaction, crack resistance, and waterproofing additive, comprising the following steps:

[0014] S1, mix nano-modified chitin with water evenly, and stir under ultrasonic dispersion for 20-40 minutes to form a uniform slurry;

[0015] S2, add polyferric sulfate and anhydrous sodium sulfate to the slurry in sequence, control the temperature at 23-27℃, control the stirring speed at 500-600rpm, and control the stirring time at 10-30min;

[0016] S3, after standing and defoaming, adjust the pH value to 6.5-7.5 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0017] The beneficial effects of this invention are as follows: A concrete compaction and crack-resistant waterproofing additive, prepared by mixing nano-modified chitin with polyferric sulfate, anhydrous sodium sulfate, and water in a reasonable ratio, exhibits excellent advantages in strength, electrical flux, and tensile strength when combined with ultrasonic dispersion and microwave modification. This solves the problem of uneven dispersion in traditional additives, improves material uniformity, and enhances its film-forming and crack-resistant properties. The high sulfate group content of polyferric sulfate promotes crystallization and compaction, forming a synergistic effect with the coagulating effect of sodium sulfate. This helps to reduce the decay of waterproofing capacity, extend the duration of compact waterproofing, improve early strength, and inhibit shrinkage cracks. A temperature-adjusting agent, prepared by mixing paraffin-based oil, alkylphenol polyoxyethylene ether, trimethylolpropane ester, silane coupling agent, and water in a suitable ratio, enhances the crack resistance of the compaction and crack-resistant waterproofing additive during high-temperature and low-temperature seasons. Detailed Implementation

[0018] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0019] I. Materials

[0020] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.

[0021] (1) The surface modifier used in this invention is BH-S1470 produced by Shanghai Bohu Biotechnology Co., Ltd.

[0022] (2) In this invention, the Zeta potential refers to the potential difference between the sliding surface of the particle and the dispersion medium, and the unit is millivolt (mV).

[0023] (3) The silane coupling agent used in this invention is model KH-550 produced by Nanjing Shuguang Chemical Group.

[0024] (4) The silicone oil emulsifier used in this invention is dimethyl silicone oil emulsifier 1# produced by Nantong Chenrun Chemical Co., Ltd.

[0025] II. Implementation Methods

[0026] Example 1

[0027] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 5 parts polyferric sulfate, 3 parts nano-modified chitosan, 1 part anhydrous sodium sulfate, and 60 parts water.

[0028] The raw materials for preparing nano-modified chitin, by weight, include: 3 parts chitin, 50 parts hydrochloric acid solution with a concentration of 60%, 50 parts sodium hydroxide solution with a concentration of 60%, 60 parts deionized water, and 7 parts surface modifier.

[0029] The raw materials for preparing the temperature-appropriate agent include: 6 parts paraffin-based oil, 3 parts alkylphenol polyoxyethylene ether, 3 parts trimethylolpropane ester, 2 parts silane coupling agent, 3 parts silicone oil, 3 parts silicone oil emulsifier, and 6 parts water.

[0030] The content of sulfuric acid groups in polyferric sulfate is 18%;

[0031] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0032] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 20 min at a temperature of 70°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added to adjust the pH to a net charge on the particles and an absolute value of 30 mV for the Zeta potential, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 200 nm are removed by centrifugation. Nanoscale chitin with a particle size of 200 nm is obtained by differential centrifugation; (vii) Nanoscale chitin with a particle size of 200 nm is obtained by microwave-assisted modification treatment at a power of 200 W.

[0033] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0034] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 20 minutes to form a uniform slurry.

[0035] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 23℃, control the stirring speed at 500 rpm, and control the stirring time at 10 min.

[0036] After standing and defoaming, the pH value is adjusted to 6.5 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0037] Example 2

[0038] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0039] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0040] The raw materials for preparing the temperature-appropriate agent, by weight, include: 7 parts paraffinic oil, 4 parts alkylphenol polyoxyethylene ether, 6 parts trimethylolpropane ester, 3 parts silane coupling agent, 4 parts silicone oil, 4 parts silicone oil emulsifier, and 7 parts water.

[0041] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0042] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0043] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes at a temperature of 80°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added to adjust the pH to a net charge on the particles and an absolute value of 35mV for the Zeta potential, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 150nm are removed by centrifugation, and nanoscale chitin with a particle size of 150nm is obtained by differential centrifugation; (vii) Nanoscale chitin with a particle size of 150nm is modified by microwave-assisted modification at a power of 200W to obtain nanoscale modified chitin.

[0044] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0045] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0046] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0047] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0048] Example 3

[0049] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 10 parts polyferric sulfate, 8 parts nano-modified chitosan, 3 parts anhydrous sodium sulfate, and 100 parts water.

[0050] The raw materials for preparing nano-modified chitin, by weight, include: 6 parts chitin, 80 parts hydrochloric acid solution with a concentration of 60%, 80 parts sodium hydroxide solution with a concentration of 90 parts deionized water, and 16 parts surface modifier.

[0051] The raw materials for preparing the temperature-appropriate agent include: 8 parts paraffin-based oil, 5 parts alkylphenol polyoxyethylene ether, 9 parts trimethylolpropane ester, 4 parts silane coupling agent, 5 parts silicone oil, 5 parts silicone oil emulsifier, and 8 parts water.

[0052] The content of sulfuric acid groups in polyferric sulfate is 24%;

[0053] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0054] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 30 min at a temperature of 90°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added and the pH is adjusted to ensure that the particles have a net charge and the absolute value of the Zeta potential is 40 mV, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 200 nm are removed by centrifugation to obtain nanoscale chitin with a particle size of 100 nm; (vii) The nanoscale chitin with a particle size of 100 nm is modified by microwave with a power of 200 W to obtain nanoscale modified chitin.

[0055] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0056] Nanoscale modified chitin was uniformly mixed with water and stirred under ultrasonic dispersion for 40 minutes to form a uniform slurry.

[0057] Polyferric sulfate and anhydrous sodium sulfate were added to the slurry in sequence, the temperature was controlled at 27℃, the stirring speed was controlled at 600 rpm, and the stirring time was controlled at 30 min.

[0058] After standing and defoaming, the pH value is adjusted to 7.5 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0059] Comparative Example 1

[0060] A concrete compaction, crack resistance, and waterproofing additive, wherein the raw materials for preparing the concrete compaction, crack resistance, and waterproofing additive include: 7 parts polyferric sulfate, 6 parts chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water, by weight.

[0061] The raw materials for preparing the temperature-appropriate agent, by weight, include: 7 parts paraffinic oil, 4 parts alkylphenol polyoxyethylene ether, 6 parts trimethylolpropane ester, 3 parts silane coupling agent, 4 parts silicone oil, 4 parts silicone oil emulsifier, and 7 parts water.

[0062] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0063] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0064] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0065] Chitosan and water were mixed evenly and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0066] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0067] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0068] Comparative Example 2

[0069] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0070] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0071] The raw materials for preparing the temperature-appropriate agent, by weight, include: 7 parts paraffinic oil, 4 parts alkylphenol polyoxyethylene ether, 6 parts trimethylolpropane ester, 3 parts silane coupling agent, 4 parts silicone oil, 4 parts silicone oil emulsifier, and 7 parts water.

[0072] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0073] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0074] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes at a temperature of 80°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and initially dispersed by ultrasonic treatment; (v) Surface modifiers are added and the pH is adjusted to ensure that the particles have a net charge and the absolute value of the Zeta potential is 35mV, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 150nm are removed by centrifugation. Nanoscale modified chitin with a particle size of 150nm is obtained by differential centrifugation.

[0075] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0076] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0077] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0078] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0079] Comparative Example 3

[0080] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0081] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0082] The raw materials for preparing the temperature-appropriate agent, by weight, include: 7 parts paraffinic oil, 4 parts alkylphenol polyoxyethylene ether, 6 parts trimethylolpropane ester, 3 parts silane coupling agent, 4 parts silicone oil, 4 parts silicone oil emulsifier, and 7 parts water.

[0083] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0084] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0085] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes, and the stirring temperature is controlled at 80℃; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Nanoscale modified chitin is obtained by centrifugation, washing and drying.

[0086] The specific preparation method of the temperature-appropriate agent is as follows: (I) Heat the paraffin-based oil to a liquid state, add alkylphenol polyoxyethylene ether, slowly add water under high shear dispersion conditions, and continuously stir until the system is stable and forms a low-viscosity emulsion. Control the temperature at 90℃ to obtain a paraffin-based oil emulsion; (II) Mix trimethylolpropane ester with silicone oil, add a silane coupling agent, and then mix with a silicone oil emulsifier. Shear the mixture through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (III) Mix the paraffin-based oil emulsion with the composite emulsion and shear the mixture until the system is completely stable to obtain a temperature-appropriate agent;

[0087] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0088] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0089] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0090] Comparative Example 4

[0091] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0092] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0093] The raw materials for preparing the temperature-appropriate agent, by weight, include: 10 parts trimethylolpropane ester, 5 parts silane coupling agent, 7 parts silicone oil, 6 parts silicone oil emulsifier, and 7 parts water.

[0094] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0095] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0096] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes at a temperature of 80°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added to adjust the pH to a net charge on the particles and an absolute value of 35mV for the Zeta potential, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 150nm are removed by centrifugation, and nanoscale chitin with a particle size of 150nm is obtained by differential centrifugation; (vii) Nanoscale chitin with a particle size of 150nm is modified by microwave-assisted modification at a power of 200W to obtain nanoscale modified chitin.

[0097] The specific preparation method of the temperature-appropriate agent is as follows: Trimethylolpropane ester is mixed with silicone oil, a silane coupling agent is added, and then it is mixed with silicone oil emulsifier. The mixture is then sheared by a high-shear emulsifier until the particle size is uniform to obtain the temperature-appropriate agent.

[0098] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0099] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0100] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0101] Comparative Example 5

[0102] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0103] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0104] The raw materials for preparing the temperature-appropriate agent, by weight, include: 10 parts paraffinic oil, 6 parts alkylphenol polyoxyethylene ether, 7 parts silicone oil, 5 parts silicone oil emulsifier, and 7 parts water.

[0105] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0106] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0107] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes at a temperature of 80°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added to adjust the pH to a net charge on the particles and an absolute value of 35mV for the Zeta potential, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 150nm are removed by centrifugation, and nanoscale chitin with a particle size of 150nm is obtained by differential centrifugation; (vii) Nanoscale chitin with a particle size of 150nm is modified by microwave-assisted modification at a power of 200W to obtain nanoscale modified chitin.

[0108] The specific preparation method of the temperature-appropriate agent is as follows: (i) heating paraffin-based oil to a liquid state, adding alkylphenol polyoxyethylene ether, slowly adding water under high shear dispersion conditions, and continuously stirring until the system is stable and forms a low-viscosity emulsion, controlling the temperature at 90℃ to obtain a paraffin-based oil emulsion; (ii) mixing silicone oil with silicone oil emulsifier, and shearing it through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (iii) mixing the paraffin-based oil emulsion with the composite emulsion, and shearing it until the system is completely stable to obtain the temperature-appropriate agent;

[0109] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0110] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0111] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0112] Comparative Example 6

[0113] A concrete compaction, crack resistance, and waterproofing additive, by weight, comprises the following raw materials: 7 parts polyferric sulfate, 6 parts nano-modified chitosan, 2 parts anhydrous sodium sulfate, and 80 parts water.

[0114] The raw materials for preparing nano-modified chitin, by weight, include: 4 parts chitin, 65 parts hydrochloric acid solution with a concentration of 60%, 65 parts sodium hydroxide solution with a concentration of 75 parts deionized water, and 12 parts surface modifier.

[0115] The raw materials for preparing the temperature-appropriate agent, by weight, include: 9 parts paraffinic oil, 6 parts alkylphenol polyoxyethylene ether, 8 parts trimethylolpropane ester, 5 parts silane coupling agent, and 7 parts water.

[0116] The content of sulfuric acid groups in polyferric sulfate is 20%;

[0117] A method for preparing a concrete compaction, crack resistance, and waterproofing additive, characterized by comprising the following steps:

[0118] The specific preparation method of nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 25 minutes at a temperature of 80°C; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing, and drying; (iv) Pure nano-chitin is added to deionized water and subjected to ultrasonic treatment to achieve preliminary dispersion; (v) Surface modifiers are added to adjust the pH to a net charge on the particles and an absolute value of 35mV for the Zeta potential, thus obtaining a uniform suspension; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 150nm are removed by centrifugation, and nanoscale chitin with a particle size of 150nm is obtained by differential centrifugation; (vii) Nanoscale chitin with a particle size of 150nm is modified by microwave-assisted modification at a power of 200W to obtain nanoscale modified chitin.

[0119] The specific preparation method of the temperature-appropriate agent is as follows: (i) heating paraffin-based oil to a liquid state, adding alkylphenol polyoxyethylene ether, slowly adding water under high shear dispersion conditions, and continuously stirring until the system is stable and forms a low-viscosity emulsion, controlling the temperature at 90℃ to obtain a paraffin-based oil emulsion; (ii) mixing trimethylolpropane ester with a silane coupling agent, and shearing it through a high-shear emulsifier until the particle size is uniform to obtain a composite emulsion; (iii) mixing the paraffin-based oil emulsion with the composite emulsion, and shearing it until the system is completely stable to obtain the temperature-appropriate agent;

[0120] Nanoscale modified chitin was mixed evenly with water and stirred under ultrasonic dispersion for 30 minutes to form a uniform slurry.

[0121] Add polyferric sulfate, anhydrous sodium sulfate, and temperature-appropriate agent to the slurry in sequence, control the temperature at 25℃, control the stirring speed at 550 rpm, and control the stirring time at 20 min.

[0122] After standing and defoaming, the pH value is adjusted to 7 to obtain a concrete compaction, crack resistance, and waterproofing additive.

[0123] III. Experimental Methods

[0124] 3.1 Tests on compressive strength, electrical conductivity, and tensile strength of concrete after adding a compacting, crack-resistant, and waterproofing additive.

[0125] 1) Experimental steps:

[0126] ① The concrete compaction, crack resistance and waterproofing additives prepared in Examples 1-3 and Comparative Examples 1-3 are numbered 1-6. Each number is mixed evenly with cement, aggregate and water, and the mixing time is controlled at 30 minutes to obtain concrete 1-concrete 6. The concrete compaction, crack resistance and waterproofing additives account for 1.5%-3.0% of the total mass of concrete.

[0127] ②At 29 days, the compressive strength of concrete 1 to concrete 6 was tested in accordance with GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete";

[0128] ③ At 29 days, the electrical charge on concrete 1 to concrete 6 was tested according to GB / T 50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete";

[0129] ④ At 29 days, the tensile values ​​of concrete 1 to concrete 6 were tested according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete";

[0130] The results are shown in the table below:

[0131] project Compressive strength (MPa) Electricity supplied (coulombs) Tensile value (micro-strain) Example 1 25.8 687 132 Example 2 29.2 452 152 Example 3 27.2 768 111 Comparative Example 1 25.1 1940 82 Comparative Example 2 26.9 1153 97 Comparative Example 3 27.1 1473 101

[0132] As can be seen from the table above, compared with Examples 1, 3 and Comparative Examples 1-3, the concrete compaction and crack-resistant waterproofing additive prepared by nano-modified chitin, polyferric sulfate, anhydrous sodium sulfate and water in a reasonable ratio, combined with ultrasonic dispersion and microwave modification, has good advantages in strength, electrical flux and tensile strength. It solves the problem of uneven dispersion of traditional additives, improves material uniformity, enhances its film-forming crack-resistant performance. The high sulfuric acid group content of polyferric sulfate promotes crystallization and compaction, forming a synergistic effect with the coagulation-promoting effect of sodium sulfate. This helps to resist the decline of waterproofing ability, increase the duration of compact waterproofing, improve early strength and inhibit shrinkage cracks.

[0133] 3.2 Crack resistance test of concrete after adding compacting, crack-resistant, and waterproofing additive in high-temperature and low-temperature seasons

[0134] 1) Experimental steps:

[0135] ① The concrete compaction, crack resistance and waterproofing additives prepared in Examples 1-3 and Comparative Examples 1-3 are numbered 1-6. Each number is mixed evenly with cement, aggregate and water, and the mixing time is controlled at 30 minutes to obtain concrete 1-concrete 6. The concrete compaction, crack resistance and waterproofing additives account for 1.5%-3.0% of the total mass of concrete.

[0136] ②Based on the high-temperature test method in the "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2024), crack resistance test was conducted on concrete after adding a compacting, crack-resistant, and waterproofing additive during the high-temperature season.

[0137] ③Based on the rapid freezing method in the "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2024), crack resistance test was conducted on concrete after adding a compacting, crack-resistant, and waterproof additive during the low-temperature season.

[0138] The results are shown in the table below:

[0139] project Ultimate tensile strength (εp) Example 2 <![CDATA[0.981×10 -4 ]]> Comparative Example 1 <![CDATA[0.852×10 -4 ]]> Comparative Example 2 <![CDATA[0.841×10 -4 ]]> Comparative Example 3 <![CDATA[0.822×10 -4 ]]>

[0140] Crack resistance during high-temperature season

[0141] project Freeze resistance rating Example 2 D150 Comparative Example 1 D100 Comparative Example 2 D100 Comparative Example 3 D100

[0142] Crack resistance in low-temperature seasons

[0143] As can be seen from the table above, compared with Comparative Examples 4-6, the prepared dense crack-resistant and waterproof additive in Example 2 showed the best performance in crack resistance tests during high-temperature and low-temperature seasons. The temperature-appropriate agent, made from paraffin-based oil, alkylphenol polyoxyethylene ether, trimethylolpropane ester, silane coupling agent, and water in appropriate proportions, improved the crack resistance of the dense crack-resistant and waterproof additive when used in high-temperature and low-temperature seasons.

[0144] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A concrete compaction, crack resistance, and waterproofing additive, characterized in that, The raw materials for preparing the concrete compaction, crack resistance, and waterproofing additive, by weight, include: 5-10 parts polyferric sulfate, 3-8 parts nano-modified chitosan, 1-3 parts anhydrous sodium sulfate, 60-100 parts water, and 2-6 parts temperature-adapting agent.

2. The concrete compaction, crack resistance, and waterproofing additive according to claim 1, characterized in that, The polyferric sulfate contains ≥18% sulfuric acid groups.

3. The concrete compaction, crack resistance, and waterproofing additive according to claim 2, characterized in that, The specific preparation method of the nanoscale modified chitin is as follows: (i) Chitin is placed in a 60% hydrochloric acid solution and stirred for 20-30 min, and the stirring temperature is controlled at 70-90℃; (ii) The hydrochloric acid solution is neutralized with a 60% sodium hydroxide solution to obtain chitin nanofibers; (iii) Pure nano-chitin is obtained by centrifugation, washing and drying; (iv) Pure nano-chitin is added to deionized water and initially dispersed by ultrasonic treatment; (v) Surface modifier is added and the pH is adjusted to the point that the particles have a net charge and the absolute value of the Zeta potential is >30mV, and finally a uniform suspension is obtained; (vi) Dynamic light scattering is used to screen the nano-chitin suspension by particle size, and agglomerates with a particle size greater than 200nm are removed by centrifugation, and nano-chitin with a particle size ≤200nm is obtained; (vii) Nano-chitin with a particle size ≤200nm is modified by microwave-assisted modification to obtain nano-scale modified chitin.

4. The concrete compaction, crack resistance, and waterproofing additive according to claim 3, characterized in that, in, By weight, the raw materials for preparing nano-modified chitin include: 3-6 parts chitin, 50-80 parts 60% hydrochloric acid solution, 50-80 parts sodium hydroxide solution, 60-90 parts deionized water, and 7-16 parts surface modifier.

5. The concrete compaction, crack resistance, and waterproofing additive according to claim 1, characterized in that, in, The raw materials for preparing the temperature-appropriate agent include: 6-8 parts paraffin-based oil, 3-5 parts alkylphenol polyoxyethylene ether, 3-9 parts trimethylolpropane ester, 2-4 parts silane coupling agent, 3-5 parts silicone oil, 3-5 parts silicone oil emulsifier, and 6-8 parts water.

6. The concrete compaction, crack resistance, and waterproofing additive according to claim 5, characterized in that, The specific preparation method of the temperature-adaptive agent is as follows: (i) heating paraffinic oil to a liquid state, adding alkylphenol polyoxyethylene ether, slowly adding water under high shear dispersion conditions, continuously stirring until the system is stable and forms a low-viscosity emulsion, controlling the temperature at 90°C, to obtain a paraffinic oil emulsion; (ii) mixing trimethylolpropane ester with silicone oil, adding a silane coupling agent, and then mixing with a silicone oil emulsifier, shearing the mixture through a high-shear emulsifier until the particle size is uniform, to obtain a composite emulsion; (iii) mixing the paraffinic oil emulsion with the composite emulsion, shearing the mixture until the system is completely stable, to obtain the temperature-adaptive agent.

7. A method for preparing a concrete compaction, crack-resistant, and waterproof additive as described in any one of claims 1-6, characterized in that, Includes the following steps: S1, mix nano-modified chitin with water evenly, and stir under ultrasonic dispersion for 20-40 minutes to form a uniform slurry; S2, add polyferric sulfate, anhydrous sodium sulfate and temperature-appropriate agent to the slurry in sequence, control the temperature at 23-27℃, control the stirring speed at 500-600rpm, and control the stirring time at 10-30min. S3, after standing and defoaming, adjust the pH value to 6.5-7.5 to obtain a concrete compaction, crack resistance, and waterproofing additive.