Concrete admixture and preparation method thereof
By leveraging the synergistic effects of rice husk ash, waste glass powder, and modified solid waste, the problems of insufficient impermeability and corrosion resistance in concrete were solved, achieving efficient and economical performance improvement while simplifying the process.
Patent Information
- Application Number
- CN202511001375.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-10-24
AI Technical Summary
Existing concrete materials have shortcomings in terms of impermeability and corrosion resistance, and are particularly susceptible to erosion by harmful ions in certain environments, leading to reduced structural strength. Furthermore, existing improvement measures may increase costs or be difficult to control.
Rice husk ash, waste glass powder, and modified solid waste are used as concrete admixtures. CSH gel is generated through the reaction of rice husk ash with cement pozzolanic material. Waste glass powder promotes gel formation and improves fluidity. Modified solid waste seals pores and inhibits ion penetration. Combined with Bacillus subtilis metabolites, a dense membrane is formed to improve impermeability and corrosion resistance.
It significantly improves the impermeability and corrosion resistance of concrete, while reducing production costs and process complexity, and realizing the resource utilization of various solid wastes.
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Figure BDA0005509012910000081
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of concrete admixtures, and particularly relates to a concrete admixture and a preparation method thereof. BACKGROUND
[0002] Concrete refers to a material obtained by uniformly mixing cement as a main gel material, water, sand, gravel, chemical additives and admixtures, and then shaping and hardening; with the continuous improvement of engineering requirements, the performance requirements of concrete materials are increasingly strict, and the current concrete materials mainly have the defects of poor toughness, insufficient impermeability and low corrosion resistance, etc. In some marine, underground water or surface spraying deicing salt environments, the concrete structure is often eroded and damaged by harmful ions in the surrounding environment, and due to the existence of pores in the concrete, the concrete has the possibility of water permeation, which further causes stress damage in the concrete, thereby reducing the strength of the concrete structure and affecting the service life and use of the concrete, and therefore developing a concrete with good impermeability and corrosion resistance has become a hot research issue.
[0003] At present, in order to improve the impermeability and corrosion resistance, the existing concrete mainly includes the following aspects: adding water-proofing agents and water-reducing agents and other admixtures in the concrete, the addition of these admixtures can fill the capillary pores, reduce the water consumption, and thus reduce the porosity of the concrete; using corrosion-resistant cement, such as using cement with low content of aluminate tricalcium for specific erosion environment; strictly controlling the concrete proportioning, vibration compaction degree and curing conditions during construction to ensure the quality of the concrete. However, the use of admixtures may increase the cost, or cause compatibility problems with other materials in the concrete; the use of corrosion-resistant cement also increases the production cost; and improving the construction process requires strict quality control, otherwise it is difficult to achieve the expected effect. Therefore, how to significantly improve the impermeability and corrosion resistance of the concrete under the premise of effectively controlling the cost has become a technical problem to be solved. SUMMARY
[0004] In view of the poor impermeability and corrosion resistance of the existing concrete, the present application provides a concrete admixture and a preparation method thereof. The concrete admixture provided by the present application includes rice husk ash, waste glass powder and modified solid waste, and the three components synergistically improve the impermeability of the concrete, inhibit the invasion of harmful ions, and enhance the corrosion resistance of the concrete.
[0005] To solve the above technical problems, the technical scheme provided by the present application is as follows:
[0006] The present application provides a concrete admixture, which comprises the following raw material components in mass fraction: 10-15 parts of rice husk ash, 20-25 parts of waste glass powder and 45-50 parts of modified solid waste.
[0007] The modified solid waste includes fly ash, coal cinder, calcium carbonate, and bacillus subtilis and its metabolites adsorbed on the surface of the fly ash and coal cinder.
[0008] Compared with the prior art, in the concrete admixture provided by the application, rice husk ash can fill into the pores of the concrete, the rich silicon dioxide can have a pozzolanic reaction with the cement hydration product Ca(OH)2, the pore structure of the concrete is refined by generating C-S-H gel with a low calcium-silicon ratio, the porosity of the concrete is reduced, and the impermeability and corrosion resistance of the concrete are improved; however, when only rice husk ash is doped, the fluidity of the concrete is poor, the water demand is sharply increased, and early hydration is too fast to easily cause microcracks, thereby reducing the impermeability and corrosion resistance of the concrete; the application further adds waste glass powder to the concrete, the high-silicon glass phase can further stimulate secondary hydration reaction and promote gel generation, and the spherical particle state of the waste glass powder can also have a lubricating effect, improve the slurry fluidity, reduce the phenomenon of connected pores caused by bleeding of the concrete, and improve the impermeability and corrosion resistance of the concrete.
[0009] The modified solid waste is loaded with calcium carbonate deposition substances, which can block capillary pores in the concrete and improve the impermeability of the concrete; secondly, the microbial metabolites on the surface of the modified solid waste form a dense film on the surface of the fly ash and coal cinder, inhibit the penetration of Cl - and other erosive ions, thereby improving the corrosion resistance of the concrete; in addition, the bacillus subtilis contains rich functional groups on the surface, is adsorbed on the fly ash and coal cinder, enhances the binding capacity of the fly ash and coal cinder to other components in the concrete, and participates in the hydration reaction to form stable gel, thereby significantly improving the impermeability and corrosion resistance of the concrete.
[0010] Preferably, the strain number of the bacillus subtilis is BNCC 338006.
[0011] The inventors tried to use different bacillus subtilis to treat the mixed solid waste, and finally screened out the bacillus subtilis with the strain number of BNCC 338006, which had the strongest impermeability and corrosion resistance of the concrete.
[0012] Preferably, the mass ratio of the fly ash and coal cinder is (3-3.5):1.
[0013] Preferably, the application further limits the mass ratio of the fly ash and coal cinder, which is beneficial to further improve the comprehensive performance of the concrete.
[0014] Preferably, the content of silicon dioxide in the rice husk ash is >92%.
[0015] Preferably, the particle size of the rice husk ash is 7-10 mu m.
[0016] Preferably, the particle size of the waste glass powder is 100-150 mu m.
[0017] By limiting the particle size of rice husk ash and waste glass powder, it can fill the voids in concrete, thereby improving the impermeability and corrosion resistance of concrete.
[0018] Preferably, the preparation method of the modified solid waste comprises the following steps:
[0019] The fly ash, coal cinder, soluble calcium salt and urea are added into the bacillus subtilis liquid, cultured, filtered, dried to obtain the modified solid waste.
[0020] In the preparation method of the modified solid waste provided by the application, the bacillus subtilis can secrete urease to catalyze the hydrolysis of urea to generate ammonia and carbon dioxide, the carbon dioxide is dissolved in water to form carbonate ions, which combine with calcium ions dissociated from the soluble calcium salt to generate calcium carbonate precipitate loaded on the fly ash and coal cinder; the specific microorganism surface contains abundant functional groups which can adsorb fine particles of the fly ash and coal cinder, further, the metabolic products generated by the bacillus subtilis form a dense film on the surface of the fly ash and coal cinder, and the fly ash and coal cinder treated by the bacillus subtilis are further filtered and dried to form the modified solid waste with dense structure, so that the solid waste activation and performance improvement are realized, and when the modified solid waste is applied to the concrete admixture, the impermeability and corrosion resistance of the concrete can be significantly improved.
[0021] Preferably, the concentration of the bacillus subtilis liquid is 5x10 8 CFU / mL-8x10 8 CFU / mL.
[0022] The concentration of the bacillus subtilis liquid is further limited in the application, so that the functional groups on the surface of the bacteria can fully adsorb the fly ash and coal cinder, and the calcium carbonate precipitate and microbial metabolic products are formed on the surface of the fly ash and coal cinder, thereby further improving the performance of the concrete.
[0023] Preferably, the particle size of the fly ash is 160-170 mu m.
[0024] Preferably, the particle size of the coal cinder is 500-550 mu m.
[0025] Preferably, the mass ratio of the fly ash to the bacillus subtilis liquid is (0.65-0.7):1.
[0026] The mass ratio of the fly ash to the bacillus subtilis liquid is conducive to further improving the impermeability and corrosion resistance of the concrete.
[0027] Preferably, the soluble calcium salt is calcium chloride.
[0028] By limiting the soluble calcium salt to calcium chloride, the production cost can be reduced to a certain extent.
[0029] Preferably, the concentration of the soluble calcium salt in the Bacillus subtilis culture medium is 0.1 mol / L-0.2 mol / L.
[0030] The preferred concentration of soluble calcium salt can form a specific content of calcium salt on the surface of fly ash and coal slag, further improving the performance of concrete.
[0031] Preferably, the concentration of urea in the Bacillus subtilis bacterial solution is 0.04 mol / L-0.06 mol / L.
[0032] By limiting the concentration of urea, appropriate nutrients can be provided for the metabolism of Bacillus subtilis spores, further improving the performance of concrete.
[0033] Preferably, the culture time is 45 min-55 min.
[0034] It should be further explained that the culture temperature can be room temperature.
[0035] It should be further explained that the stirring is carried out at a rate of 200 r / min-250 r / min during the reaction.
[0036] It should be further explained that the Bacillus subtilis seed liquid is inoculated into the liquid culture medium and cultured at a constant temperature with shaking to obtain the Bacillus subtilis bacterial liquid.
[0037] The liquid culture medium includes: 10 g of glucose, 5 g of urea, 1 g of potassium dihydrogen phosphate, 0.2 g of magnesium sulfate, 1 L of water, pH = 7-7.5.
[0038] The present invention provides a method for preparing the concrete admixture, comprising the following steps: uniformly mixing rice husk ash, waste glass powder and modified solid waste to obtain the concrete admixture.
[0039] The preparation method of the concrete admixture provided by the present invention only requires simple and uniform mixing of rice husk ash, waste glass powder and modified solid waste to produce the finished product. It does not require complex equipment and harsh conditions such as high temperature and high pressure, nor does it require tedious reaction steps and processing procedures. It significantly reduces the process difficulty and production cost, and embodies the outstanding advantages of simple process, easy operation and high efficiency. At the same time, it also realizes the resource utilization of various solid wastes, and has both environmental protection and economic value. DETAILED DESCRIPTION
[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0041] In order to better illustrate the present application, further examples are made below by examples.
[0042] Example 1
[0043] The embodiment of the present application provides a concrete admixture, which comprises the following raw material components in mass fractions: rice husk ash with an average particle size of 7 mu 10 parts, waste glass powder with an average particle size of 150 mu 20 parts and modified solid waste 50 parts; the content of silicon dioxide in the rice husk ash is 93.8%.
[0044] The preparation method of the modified solid waste comprises the following steps:
[0045] Fly ash, coal cinder, calcium chloride and urea are added into bacillus subtilis liquid, and the reaction is cultured at room temperature for 45 minutes, the stirring is carried out at a speed of 200 r / min during the reaction, and the modified solid waste is obtained by filtering and drying; the concentration of the bacillus subtilis liquid is 5*10 8 CFU / mL, the mass ratio of the fly ash and the bacillus subtilis liquid is 0.65:1, the concentration of the calcium chloride in the bacillus subtilis liquid is 0.1 mol / L, the concentration of the urea in the bacillus subtilis liquid is 0.06 mol / L; the particle size of the fly ash is 160 mu, the particle size of the coal cinder is 550 mu; and the mass ratio of the fly ash and the coal cinder is 3:1.
[0046] The preparation method of the bacillus subtilis liquid comprises the following steps: the seed liquid of the bacillus subtilis numbered as BNCC338006 is inoculated into a liquid culture medium, and the bacillus subtilis liquid is obtained by constant temperature vibration culture at 25 DEG C; and the liquid culture medium comprises 10 g of glucose, 5 g of urea, 1 g of potassium dihydrogen phosphate, 0.2 g of magnesium sulfate and 1 L of water, and the pH value is 7-7.5.
[0047] Example 2
[0048] The embodiment of the present application provides a concrete admixture, which comprises the following raw material components in mass fractions: rice husk ash with an average particle size of 7 mu 10 parts, waste glass powder with an average particle size of 150 mu 20 parts and modified solid waste 50 parts; the content of silicon dioxide in the rice husk ash is 93.8%.
[0049] The preparation method of the modified solid waste comprises the following steps:
[0050] Fly ash, coal cinder, calcium chloride and urea are added into bacillus subtilis liquid, and the reaction is cultured at room temperature for 55 minutes, the stirring is carried out at a speed of 250 r / min during the reaction, and the modified solid waste is obtained by filtering and drying; the concentration of the bacillus subtilis liquid is 8*10 8CFU / mL, the mass ratio of fly ash and bacillus subtilis liquid is 0.7:1, the concentration of calcium chloride in the bacillus subtilis liquid is 0.2mol / L, and the concentration of urea in the bacillus subtilis liquid is 0.04mol / L; the particle size of fly ash is 170μm, the particle size of cinder is 500μm; the mass ratio of fly ash and cinder is 3.5:1;
[0051] The preparation method of the bacillus subtilis liquid comprises the following steps: inoculating seed liquid of the bacillus subtilis numbered as BNCC338006 into a liquid culture medium, and culturing at constant temperature and oscillation at 25 DEG C to obtain the bacillus subtilis liquid, wherein the liquid culture medium comprises 10g of glucose, 5g of urea, 1g of potassium dihydrogen phosphate, 0.2g of magnesium sulfate, 1L of water, and pH is 7-7.5.
[0052] Example 3
[0053] The concrete admixture provided by the embodiment of the present application comprises the following raw material components in mass fractions: 13 parts of rice husk ash with an average particle size of 8μm, 22 parts of waste glass powder with an average particle size of 120μm, and 50 parts of modified solid waste; the content of silicon dioxide in the rice husk ash is 93.3%;
[0054] The preparation method of the modified solid waste comprises the following steps:
[0055] The fly ash, cinder, calcium chloride and urea are added into the bacillus subtilis liquid, and the reaction is carried out at room temperature for 50min, and the stirring is carried out at a speed of 250r / min during the reaction, then the modified solid waste is obtained by filtering and drying; the concentration of the bacillus subtilis liquid is 7x10 8 CFU / mL, the mass ratio of fly ash and bacillus subtilis liquid is 0.7:1, the concentration of calcium chloride in the bacillus subtilis liquid is 0.2mol / L, and the concentration of urea in the bacillus subtilis liquid is 0.04mol / L; the particle size of fly ash is 170μm, the particle size of cinder is 500μm; the mass ratio of fly ash and cinder is 3.5:1;
[0056] The preparation method of the bacillus subtilis liquid comprises the following steps: inoculating seed liquid of the bacillus subtilis numbered as BNCC338006 into a liquid culture medium, and culturing at constant temperature and oscillation at 25 DEG C to obtain the bacillus subtilis liquid, wherein the liquid culture medium comprises 10g of glucose, 5g of urea, 1g of potassium dihydrogen phosphate, 0.2g of magnesium sulfate, 1L of water, and pH is 7-7.5.
[0057] Comparative Example 1
[0058] The comparative example of the present application provides a concrete admixture, wherein the cinder is replaced by an equal amount of steel slag compared with the example 1, and other operations are the same as those in the example 1.
[0059] Comparative Example 2
[0060] The comparative example of the present application provides a concrete admixture, compared with Example 1, Bacillus subtilis is replaced by an equal amount of Bacillus licheniformis, the strain number of Bacillus licheniformis is BNCC 336463, and other operations are the same as Example 1.
[0061] Comparative Example 3
[0062] The comparative example of the present application provides a concrete admixture, compared with Example 1, waste glass powder is replaced by an equal amount of waste rubber powder, and other operations are the same as Example 1.
[0063] The concrete admixtures prepared in Examples 1-3 and Comparative Examples 1-3 are prepared according to the following proportions, and the specific proportions are as follows:
[0064] Ordinary Portland cement: concrete admixture: sand: stone: water = 300: 100: 800: 1000: 170, and the water reducing agent content is 1.0%;
[0065] The concrete prepared in Examples 1-3 and Comparative Examples 1-3 is tested for water penetration depth for impermeability and corrosion resistance, and the specific detection is as follows:
[0066] According to GB / T 50082-2009 “Standard for Testing Methods for Long-Term Performance and Durability of Ordinary Concrete”, the water penetration height method is used to test the water penetration resistance of concrete, and the concrete with a curing age of 7 days is made into a circular truncated cone with an inner diameter of 175 mm at the top and an inner diameter of 185 mm at the bottom, and a height of 150 mm, and is placed in a concrete penetration instrument for water penetration resistance test;
[0067] The concrete with a curing age of 7 days is prepared into a sample with a size of 100mm×100mm×50mm, and is placed in a 4mol / L sodium chloride solution, and then the sample is subjected to vacuum water retention treatment, and a concrete chloride ion diffusion coefficient tester is used to determine the chloride ion diffusion coefficient.
[0068] The specific test results are shown in Table 1:
[0069] Table 1 Test Results
[0070]
[0071] As can be seen from Table 1, the concrete prepared by using the admixture provided in the examples of the present application has a chloride ion diffusion coefficient as low as 6.2×10 -7cm / s, the water seepage height is as low as 6.9 mm, and the concrete has excellent impermeability and corrosion resistance; in Comparative Example 1, the coal cinder is replaced by steel slag, in Comparative Example 2, the bacillus subtilis is replaced by bacillus licheniformis, and in Comparative Example 3, the waste glass powder is replaced by waste rubber powder, but the impermeability and corrosion resistance of the concrete prepared by using the admixture provided in Comparative Examples 1-3 are significantly lower than those of the concrete prepared in the embodiments of the present application, and the admixture provided in the present application adds rice husk ash, waste glass powder and modified solid waste, which synergistically improves the impermeability of the concrete, simultaneously inhibits the invasion of harmful ions and enhances the corrosion resistance of the concrete.
[0072] The above merely provides the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A concrete admixture characterized by, The raw material components include the following mass fractions: rice husk ash 10-15 parts, waste glass powder 20-25 parts, and modified solid waste 45-50 parts. The modified solid waste includes fly ash, coal cinder, calcium carbonate, and Bacillus subtilis and its metabolites adsorbed on the surfaces of the fly ash and coal cinder.
2. The concrete admixture of claim 1, wherein The strain number of the Bacillus subtilis is BNCC 338006; and / or The mass ratio of the fly ash to the coal cinder is (3-3.5):
1.
3. The concrete admixture of claim 1, wherein The particle size of the rice husk ash is 7-10 mu m; and / or The particle size of the waste glass powder is 100-150 mu m.
4. Concrete admixture according to any one of claims 1 to 3, characterized in that The preparation method of the modified solid waste includes the following steps: The fly ash, coal cinder, soluble calcium salt, and urea are added into the Bacillus subtilis bacterial liquid, cultured, filtered, dried, and the modified solid waste is obtained.
5. The concrete admixture of claim 4, wherein The concentration of the B. subtilis bacterial solution is 5 x 10 8 CFU / mL-8 x 10 8 CFU / mL.
6. The concrete admixture of claim 4, wherein The particle size of the fly ash is 160-170 mu m; and / or The particle size of the coal cinder is 500-550 mu m.
7. The concrete admixture of claim 4, wherein The mass ratio of the fly ash to the Bacillus subtilis bacterial liquid is (0.65-0.7):
1.
8. The concrete admixture of claim 4, wherein The concentration of the soluble calcium salt in the Bacillus subtilis bacterial liquid is 0.1-0.2 mol / L; and / or The concentration of the urea in the Bacillus subtilis bacterial liquid is 0.04-0.06 mol / L.
9. The concrete admixture of claim 4, wherein The culture time is 45-55 min.
10. A method of producing the concrete admixture according to any one of claims 1 to 9, characterized by, The method includes the following steps: uniformly mixing the rice husk ash, waste glass powder, and modified solid waste to obtain a concrete admixture.