Preparation method, application and use method of cement-based material chloride ion permeation resistant admixture
By preparing a cement-based material chloride ion penetration resistant admixture using microalgae extract and CA powder, the problem of chloride ion penetration in reinforced concrete structures was solved, improving the material's chloride ion penetration resistance and strength, and ensuring structural safety and durability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HOHAI UNIV
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-01
AI Technical Summary
In the prior art, reinforced concrete structures are susceptible to corrosion due to chloride ion penetration, which affects the durability and safety of the structure. Furthermore, the use of rust inhibitors may impair the compactness and chloride ion penetration resistance of concrete.
A chloride ion penetration resistant admixture for cement-based materials was prepared by mixing microalgae extract with CA powder. The admixture generates complexes that fill pores and microcracks, thereby improving the material density and delaying the development of CSH in the early hydration stage, thus increasing the growth space of hydration products.
It significantly improves the chloride ion penetration resistance and strength of cement-based materials, reduces the chloride ion migration and diffusion coefficient, enhances chemical adsorption capacity, improves pore structure, and increases flexural and compressive strength.
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Abstract
Description
Preparation method, application and usage of a cement-based material chloride ion penetration resistant admixture Technical Field
[0001] This invention relates to a method for preparing and using an anti-chloride ion permeation admixture, and more particularly to a method for preparing and using an anti-chloride ion permeation admixture for cement-based materials. Background Technology
[0002] Reinforced concrete, as a civil engineering material with excellent comprehensive performance, has a wide range of applications. With the continuous advancement of reinforced concrete technology, its role in building structures such as bridges, tunnels, and water conservancy projects is becoming increasingly important. However, reinforced concrete structures are always affected by various environmental factors during operation, leading to steel corrosion. In severe cases, this can result in structural failure or damage before the expected service life. Chloride ion penetration is one of the main factors causing the failure of reinforced concrete structures. This corrosion not only shortens the service life of building structures but can also cause huge economic losses and safety hazards.
[0003] Among numerous corrosion prevention measures, the application of steel reinforcement corrosion inhibitors is considered a highly efficient solution. However, the introduction of corrosion inhibitors may negatively impact the compactness and chloride ion penetration resistance of concrete.
[0004] To address the aforementioned issues, there is an urgent need for a low-cost, widely available, and environmentally friendly admixture that can significantly improve the chloride ion penetration resistance of reinforced concrete structures while ensuring the safety of engineering structures and the workability of concrete, thereby providing a strong guarantee for the safety and durability of reinforced concrete structures. Summary of the Invention
[0005] Purpose of the invention: The purpose of this invention is to provide a method for preparing an admixture for resisting chloride ion penetration in cement-based materials. This admixture can simultaneously improve the chloride ion penetration resistance, flexural strength, and compressive strength of cement-based materials.
[0006] The second objective of this invention is to provide the application of the anti-chloride ion permeation admixture for cement-based materials obtained by the above method in the preparation of cement-based materials; the third objective of this invention is to provide a method for using the anti-chloride ion permeation admixture for cement-based materials obtained by the above method.
[0007] Technical solution: The preparation method of the cement-based material anti-chloride ion penetration admixture of the present invention includes the following steps:
[0008] (1) Wash, filter, and break the cell walls of the microalgae to obtain the microalgae stock solution;
[0009] (2) Add anhydrous ethanol to the microalgae stock solution, evaporate and concentrate to obtain concentrated extract;
[0010] (3) Centrifuge the concentrated extract, take the supernatant and freeze-dry it to obtain microalgae extract, grind it and sieve it to obtain powdered extract;
[0011] (4) Mix the powdered extract with CA powder to obtain the cement-based material anti-chloride ion penetration admixture.
[0012] In step (2) evaporation and concentration, the temperature of the rotary evaporator is set to 40~50℃ and the rotation speed is 200~300r / min.
[0013] In step (3), ultrasonic treatment is performed before centrifugation; the ultrasonic frequency is 40±2KHz, the ultrasonic power is 60W, the ultrasonic temperature is 20~80℃, and the ultrasonic duration is 1~3h.
[0014] In step (3), the centrifuge used for centrifugation has a rotation speed of 1900~2100 r / min and a centrifugation time of 9~11 min.
[0015] In step (3) freeze-vacuum drying, the temperature of the freeze-vacuum dryer is -50~-60℃ and the drying time is 12h~24h.
[0016] In step (3), the sieve size is 700-800 mesh.
[0017] In step (4), the CA powder comprises the following components by mass percentage: 60%~80% glucose, 7.5%~15% glycine, 7.5%~15% glutamic acid, and 5%~10% nano-silica.
[0018] The application of the chloride ion penetration resistant admixture obtained by the above method in the preparation of cement-based materials.
[0019] The dosage of the anti-chloride ion penetration admixture in the cement-based material is 3wt.%~8wt.% of the cement-based material.
[0020] The above method provides the method for using the cement-based material anti-chloride ion permeation admixture: mix the cement-based material anti-chloride ion permeation admixture with mixing water and stir for 30 seconds to 5 minutes, then mix the stirred suspension with the cement-based material.
[0021] Invention Principle: This invention uses microalgae extract as an admixture to resist chloride ion penetration in green cement-based materials. The incorporation of this admixture has a significant impact on the hydration process of cement paste: In the early hydration stage, the microalgae extract effectively delays the development of CSH. Since the sample with added microalgae extract has a higher porosity, it has a larger space for the growth of hydration products, which helps to form more CSH in the later stage, ultimately enhancing the chloride ion binding capacity of the cement-based material.
[0022] The green cement-based material anti-chloride ion penetration admixture of this invention mainly consists of microalgae extract. This admixture needs to be pre-stirred with mixing water to form a suspension, which is then mixed with the cement-based material. The organic matter contained therein reacts with Ca... 2+ The formation of complexes may fill the pores and microcracks in cement-based materials, making them more compact and thus improving their flexural and compressive strength.
[0023] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects:
[0024] (1) The admixture of the present invention can enhance the chemical adsorption capacity of mortar matrix for chloride ions by reducing the chloride ion migration coefficient and chloride ion diffusion coefficient; at the same time, it can effectively improve the pore structure characteristics of mortar and reduce porosity; through the above synergistic effect, it can improve the chloride ion penetration resistance of mortar and enhance the flexural and compressive strength of cement-based materials. (2) The present invention uses microalgae extract as a green cement-based material chloride ion penetration resistance admixture, wherein the organic matter contained therein reacts with Ca 2+ The formation of complexes can fill the pores and microcracks in cement-based materials, making them more compact and thus improving their flexural and compressive strength. Attached Figure Description
[0025] Figure 1 shows the D values of cement-based materials obtained in Examples 1-7 and the control group, with chloride ion penetration resistant admixture dosages of 2%, 3%, 4%, 6%, 8%, 16%, and 24% and a water-cement ratio of 0.5. RCM Test results;
[0026] Figure 2 shows the distribution of chloride ions in the mortar of the samples from Examples 1-7 and the control group after soaking in 16.5% NaCl solution for 90 days. Detailed Implementation
[0027] The present invention will now be described in further detail.
[0028] Example 1
[0029] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0030] Microalgae were washed and filtered. The filtered microalgae were then placed in a cell wall disruptor for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at a temperature of 40°C and a rotation speed of 200 r / min to obtain a concentrated extract. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40±2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The concentrated extract was then centrifuged at a speed of 2000 r / min for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at a temperature of -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 2% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0031] The CA powder is composed of the following components by weight percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica. Specifically, these additives play only an auxiliary role; their main function is to improve processing flowability and optimize the physical structure of the final product. They do not directly provide the core resistance to chloride ion penetration, but rather enhance the performance of the microalgae powder through physical or synergistic methods.
[0032] Example 2
[0033] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0034] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 3% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0035] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0036] Example 3
[0037] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0038] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 4% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0039] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0040] Example 4
[0041] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0042] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 6% of the cement paste mass ratio for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0043] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0044] Example 5
[0045] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0046] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 8% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0047] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0048] Example 6
[0049] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0050] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 16% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0051] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0052] Example 7
[0053] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0054] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 24% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0055] The CA powder is made from the following components by mass percentage: 80% glucose, 7.5% glycine, 7.5% glutamic acid, and 5% nano-silica.
[0056] Example 8
[0057] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0058] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 4% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0059] The CA powder is made from the following components by weight percentage: 60% glucose, 15% glycine, 15% glutamic acid, and 10% nano-silica.
[0060] Example 9
[0061] A method for preparing a novel green cement-based material chloride ion permeation resistant admixture includes the following steps:
[0062] Microalgae were washed and filtered. The filtered microalgae were then placed in a high-speed blender for cell wall disruption to obtain a microalgae stock solution. Anhydrous ethanol was added to the stock solution, and the solution was concentrated in a rotary evaporator at 40°C and 200 rpm. The concentrated extract was then subjected to ultrasonic treatment at a frequency of 40 ± 2 kHz, a power of 60 W, a temperature of 20°C, and a duration of 1 hour. The ultrasonically treated extract was then centrifuged at 2000 rpm for 10 minutes. The supernatant was frozen at -20°C for 12 hours and then freeze-dried in a freeze dryer at -60°C for 18 hours. After freeze-drying, the extract was ground and sieved through an 800-mesh sieve to obtain a powdered extract. The powdered extract was then mixed with CA powder to obtain a chloride ion permeation resistant additive for cement-based materials based on the microalgae extract. The admixture was mixed with water at a dosage of 4% of the cement paste mass for 5 minutes. The resulting suspension was then added to the cement and stirred, with a water-cement ratio of 0.5, and specimens were prepared.
[0063] The CA powder is made from the following components by weight percentage: 70% glucose, 10% glycine, 10% glutamic acid, and 7.5% nano-silica.
[0064] control group
[0065] Compared to Example 1, the difference lies in the fact that no chloride ion penetration inhibitor based on microalgae extract was added as an admixture to prepare cement mortar specimens with a water-cement ratio of 0.5. The cement used for the cement mortar specimens was P·O 42.5 ordinary Portland cement produced by Nanjing Conch Cement Co., Ltd. of China. The fine aggregate used was standard sand, and all indicators of the sand met the specifications of GB / T 17671-2021. The water used in molding the specimens was tap water.
[0066] Related tests:
[0067] Cement mortar specimens with a water-cement ratio of 0.5 were prepared for each embodiment and the control group. The specimens were 50 mm in diameter and 100 mm in height. First, cement-based anti-chloride ion penetration admixtures at dosages of 2%, 3%, 4%, 6%, 8%, 16%, and 24% were dissolved in the mixing water and thoroughly stirred until homogeneous. The mixture was then molded into test blocks. After casting, the specimens were allowed to stand for 24 hours before being removed from the molds and transferred to a standard curing chamber for curing.
[0068] (1) Compressive and flexural strength tests:
[0069] The compressive and flexural strengths of cement-based materials containing different amounts of chloride ion penetration resistant admixtures (Examples 1-9, water-cement ratio 0.5) and the control group were tested after 90 days of untreated and immersion in 16.5 wt.% NaCl solution. The results are shown in Table 1. For the compressive and flexural strength tests, the specimens were cured for 90 days. The tests were conducted using an electronic universal testing machine (DNS100) with a loading rate of 0.5 kN / s.
[0070] Table 1. Compressive and flexural strengths of Examples 1-9 and the control group
[0071]
[0072] As shown in Table 1, compared with the compressive and flexural strengths of the control group, the compressive strength of the cement paste specimens with the admixture added increased to a certain extent at all ages. The compressive strength first increased and then decreased with the increase of the admixture dosage. The 90-day compressive strengths of Examples 1-7 changed by +53.71%, +55.07%, +58.98%, +55.86%, +54.69%, +53.52%, and +52.73%, respectively; the 90-day flexural strengths of Examples 1-7 changed by +7.69%, +8.97%, +11.54%, +6.41%, +3.85%, +2.56%, and +1.28%, respectively. This indicates that the admixture of the present invention improved the compressive and flexural strengths of cement-based materials to a certain extent. Example 3 represents the optimal mix ratio, with 4% being the optimal dosage.
[0073] As shown in Table 1, compared to the compressive strength of Example 3, the 90-day compressive strength of Examples 8-9 changed by -0.01% and +0.01%, respectively; the flexural strength changed by -0.11% and +0.11%, respectively. This indicates that the proportions of the components in the CA powder have virtually no impact on the effect of the additive, suggesting that these additives play an auxiliary role. Their main function is to improve processing flowability and optimize the physical structure of the final product, allowing the microalgae powder to perform better through physical or synergistic methods.
[0074] (2) Rapid Chloride Ion Migration (RCM) Test
[0075] Rapid chloride ion migration (RCM) tests were conducted on samples of cement-based materials containing different dosages of chloride ion penetration-resistant admixtures with a water-cement ratio of 0.5 (Examples 1-7) and a control group. The mortar used for chloride ion penetration coefficient determination had dimensions of 100 mm in diameter and 50 mm in height. After reaching 28 days of curing, the mortar was immersed in saturated lime water for vacuum treatment, followed by RCM testing. After the test, the mortar was axially cut in half, and a 0.1 mol / L AgNO3 solution was sprayed onto the surface of the cut pieces. The chloride ion penetration depth and the chloride ion diffusion coefficient (D) of the mortar were measured. RCM , 10 -12 m 2 / s) is calculated using formula (1.1).
[0076]
[0077] In the formula: U is the absolute value of the applied voltage (V); Xd is the chloride ion penetration depth (mm); t is the test energizing time (h); L is the thickness of the specimen (mm).
[0078] (3) Unsteady-state natural diffusion test
[0079] Unsteady-state natural diffusion tests were conducted on samples of cementitious materials containing different amounts of chloride ion penetration resistant admixtures with a water-cement ratio of 0.5 and their control groups. After 28 days of curing, the mortar was soaked in a 16.5% NaCl solution, with dimensions of 50 mm in diameter and 100 mm in height. The NaCl solution was replaced every four weeks. After 90 days of soaking, the mortar samples were processed layer by layer using a lathe and sieved. The samples were dried at 60℃ for 1 day, and the dried powder was mixed with deionized water to prepare a solution with a solid-liquid ratio of 0.1. The solution was shaken for 20 minutes and then sealed and allowed to stand at 25℃ for 2 days. The chloride ion content in the supernatant was determined using potentiometric titration. The unsteady-state migration of chloride ions in the mortar was described by Fick's second law.
[0080]
[0081] The diffusion coefficient is calculated according to equation (1.3):
[0082]
[0083] In the formula: C(x,t) is the concentration (%) of chloride ions at depth x and time t; C s The sample chloride ion concentration (%); C i Initial chloride ion concentration (%); D app The diffusion coefficient (×10) -12 m 2 / s); erf() is the Gaussian error function; t is the exposure time (s); x is the distance (m) between the test surface and the exposure surface.
[0084] Based on Fick's second law, equation (1.3) was used to fit the chloride ion concentration distribution in order to determine the unsteady-state diffusion coefficient (D) of chloride. app ) and concentration (C s The experimental data are shown in Table 2.
[0085] Table 2 shows the total chloride ion concentration and chloride ion diffusion coefficient obtained from the control group and Examples 1-7 using data fitted with Fick's second law.
[0086]
[0087] As shown in Table 2, the chloride ion concentration decreases rapidly with increasing depth, approaching zero at a depth of 25 mm. This indicates that the initial chloride ion concentration C... i= 0, meaning all chloride ions originate from infiltration from the external environment. Experimental results show that, under the same conditions, cement mortars with different dosages of cement-based anti-chloride ion admixtures exhibit varying degrees of D... app The values were all significantly lower than the control group. Specifically, when the water-cement ratio was 0.5, the values of 2%, 3%, 4%, 6%, 8%, 16%, and 24% cement-based anti-chloride ion permeation admixtures were significantly lower than the control group. app The values decreased by 24.23%, 36.50%, 42.33%, 42.77%, 43.06%, 43.21%, and 43.35%, respectively. Meanwhile, it is not difficult to observe that after adding 4% of a cement-based anti-chloride ion penetration admixture, the D of the cement mortar... app The values and total chloride ion concentration tend to stabilize.
[0088] As can be seen from Figure 1, under the same conditions, the D of the control group RCM The values were all higher than the D values of cement mortar samples with different dosages of cement-based anti-chloride ion penetration admixtures. RCM Value. Specifically, in mortar with a water-cement ratio of 0.5, D RCM The values decreased by 50.72%, 69.25%, 86.99%, 87.25%, 87.38%, 87.64%, and 87.77%, respectively. In summary, different dosages of the anti-chloride ion permeation admixtures for cement-based materials can significantly improve their resistance to chloride ion permeation, with the 4% dosage of the *Singletonya ovata* rust inhibitor showing the best performance.
[0089] As shown in Figure 2, after a depth exceeding 5 mm, the mortar sample with 4% cement-based anti-chloride ion permeation admixture exhibited the best anti-chloride ion permeation performance, with a significantly lower chloride content than the control group. The results from the RCM and natural diffusion methods demonstrate that the 4% cement-based anti-chloride ion permeation admixture is the most effective in enhancing the ability to inhibit chloride ion transport in mortar.
[0090] Overall, an analysis of the test results leads to the conclusion that, from the perspective of chloride ion diffusion, the cement-based material stabilizes after adding a 4% chloride ion penetration inhibitor. From a strength perspective, the 4% chloride ion penetration inhibitor provides the best strength. Therefore, considering all the data, a 4% chloride ion penetration inhibitor is the optimal dosage for cement-based materials.
Claims
1. A method for preparing a chloride ion penetration resistant admixture for cement-based materials, characterized in that, Includes the following steps: (1) Wash, filter, and break the cell walls of the microalgae to obtain the microalgae stock solution; (2) Add anhydrous ethanol to the microalgae stock solution, evaporate and concentrate to obtain the concentrated extract; (3) Centrifuge the concentrated extract, take the supernatant and freeze-dry it to obtain the microalgae extract, grind and sieve to obtain the powdered extract; (4) Mix the powdered extract with CA powder to obtain the cement-based material antichloride ion penetration admixture.
2. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, In step (2) evaporation and concentration, the temperature of the rotary evaporator is set to 40~50℃ and the rotation speed is 200~300r / min.
3. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, Step (3) Perform ultrasonic treatment before centrifugation; the ultrasonic frequency is 40±2KHz, the ultrasonic power is 60W, the ultrasonic temperature is 20~80℃, and the ultrasonic duration is 1~3h.
4. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, In step (3), the centrifuge used for centrifugation has a speed of 1900~2100 r / min and a centrifugation time of 9~11 min.
5. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, In step (3) freeze-vacuum drying, the temperature of the freeze-vacuum dryer is -50~-60℃ and the drying time is 12h~24h.
6. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, In step (3), the sieve size is 700~800 mesh.
7. The preparation method of the cement-based material chloride ion penetration resistant admixture according to claim 1, characterized in that, In step (4), the CA modified powder comprises the following components by mass percentage: 60%~80% glucose, 7.5%~15% glycine, 7.5%~15% glutamic acid, and 5%~10% nano silica.
8. The application of a chloride ion penetration resistant admixture obtained by the method of any one of claims 1-7 in the preparation of cement-based materials.
9. The application according to claim 8, characterized in that, The dosage of the anti-chloride ion penetration admixture for cement-based materials is 3wt.%~8wt.% of the cement-based materials.
10. A method for using a chloride ion penetration resistant admixture in cement-based materials obtained by the method described in any one of claims 1-7, characterized in that, Mix the cement-based material anti-chloride ion penetration admixture with the mixing water and stir for 30 seconds to 5 minutes. Then mix the stirred suspension with the cement-based material.