Slow-release polycarboxylate superplasticizer for road concrete and preparation method of slow-release polycarboxylate superplasticizer

Abstract

The invention discloses a slow-release polycarboxylate superplasticizer for road concrete and a preparation method of the slow-release polycarboxylate superplasticizer. The water reducer is prepared by modifying a polycarboxylic acid molecular structure through vinyltriethoxysilane, introducing functional monomers such as 2-acrylamide-2-methylpropanesulfonic acid and itaconic acid by taking ethylene glycol monovinyl polyethylene glycol ether as a main chain and adopting a free radical polymerization process. The product has excellent slow-release performance and high-temperature adaptability, can effectively control the cement hydration process, and solves the problem of fast slump loss of the traditional water reducer. The silane group can enhance chemical bonding with cement, the durability and impermeability of concrete are improved, and meanwhile, the anti-mud performance is good. The preparation process is simple, functional modification is realized through one-step polymerization, the reaction condition is mild, and the production period is short. The water reducing agent is environment-friendly and non-toxic, can remarkably prolong the window period of road concrete construction, is suitable for high-performance concrete engineering, and ensures workability and strength while reducing the mixing amount.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of building chemical materials, and particularly relates to a slow-release polycarboxylate superplasticizer for road concrete and a preparation method thereof. BACKGROUND

[0002] Carboxylic acid superplasticizer is widely used in preparing high-strength and super-high-strength concrete due to its low dosage, high water-reducing and slump-keeping advantages. Because of the special molecular structure of polycarboxylate superplasticizer, the superplasticizer with desired performance can be prepared according to the needs. However, the slump of the concrete with the commercially available polycarboxylate superplasticizer is usually affected by the change of air temperature, transportation distance and cement variety. Especially in hot summer or long-distance transportation, the slump of the concrete is lost too fast, and the working performance of the concrete needs to be maintained by increasing the dosage of the superplasticizer or by compounding a retarder. However, increasing the dosage of the superplasticizer will cause segregation and bleeding of the concrete in the early stage of mixing, which affects the homogeneity of the concrete and reduces the compressive and flexural strength of the concrete. The retarder is prone to deterioration under high temperature, which also reduces the working performance of the concrete.

[0003] In road concrete engineering, the traditional superplasticizer faces technical bottlenecks such as insufficient slow-release performance, poor high-temperature adaptability and difficulty in balancing the strength and workability. The naphthalene and aliphatic superplasticizers are difficult to meet the construction requirements in long-distance transportation or high-temperature environment due to the problems of fast slump loss and unstable retardation. Although the ordinary polycarboxylate superplasticizer has high water-reducing rate, the single molecular structure lacks the ability to accurately control the cement hydration, and the dependence on physical mixing of retarders easily leads to strength reduction or uncontrollable release. In the prior art, although the microencapsulated retarder can achieve slow release, it is difficult to be industrialized due to the complex process and high cost. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application aims to provide a slow-release polycarboxylate superplasticizer for road concrete and a preparation method thereof. To achieve the object of the present application, the following technical solutions are adopted:

[0005] The slow-release polycarboxylate superplasticizer for road concrete is a vinyl triethoxysilane modified polycarboxylate superplasticizer. The present application further provides a preparation method of the slow-release polycarboxylate superplasticizer for road concrete, which comprises the following steps:

[0006] 1) mixing acrylic acid and vinyl triethoxysilane in a certain proportion, and dissolving in deionized water to obtain an A solution with a solute mass fraction of 70%-80%;

[0007] 2) mixing 3-mercaptopropionic acid and ascorbic acid in a certain proportion, and dissolving in deionized water to obtain a B solution with a solute mass fraction of 10%-20%;

[0008] 3) Put ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropane sulfonic acid, itaconic acid and appropriate amount of deionized water into a 250 mL reactor with stirring function, stir at 60 ℃, the stirring speed is 60 r / min, until the ethylene glycol monovinyl polyethylene glycol ether is completely dissolved; At this time, add 30% mass fraction H2O2 solution, continue to stir for 15 min, and add the A solution obtained in 1) and the B solution obtained in 2) at a constant speed, continue to add for 1 h, after adding, continue to stir, and incubate at 60 ℃ for 3 h to obtain a preliminary product;

[0009] 4) Add 30% mass fraction NaOH aqueous solution to the preliminary product obtained in step 3) to adjust the pH value to 6-7 to obtain a final product.

[0010] Preferably, in the preparation method of the slow-release polycarboxylate superplasticizer for road concrete, the raw material ratio used is: acrylic acid: vinyl triethoxysilane: ethylene glycol monovinyl polyethylene glycol ether: 2-acrylamide-2-methylpropane sulfonic acid: itaconic acid = 1: (0.022-0.216): (0.178-0.324): (0.033-0.338): (0.044-0.081).

[0011] Preferably, in the preparation method of the slow-release polycarboxylate superplasticizer for road concrete, the 3-mercaptopropionic acid in 2) accounts for 0.01%-0.09% of the total amount of the system in 3), and the ascorbic acid accounts for 0.01%-0.03% of the total amount of the system in 3).

[0012] Preferably, in the preparation method of the slow-release polycarboxylate superplasticizer for road concrete, the 30% mass fraction H2O2 used in 3) accounts for 0.4%-0.12% of the total amount of the system in 3).

[0013] Preferably, in the preparation method of the slow-release polycarboxylate superplasticizer for road concrete, the solid content of the final product is 40%.

[0014] Reaction process:

[0015] 1) Storage: store in a cool and dry place, preferably at 5-30 ℃, avoid direct sunlight, the shelf life is usually 6-12 months. Regularly check the uniformity of the liquid, if there is stratification, stir until completely mixed; the solid content is about 40%, and the pH value is between 6-7;

[0016] 2) If conventional concrete is prepared, 0.15%-0.3% of the mass of the concrete material is needed; if high-strength and durable concrete is needed, 0.25%-0.4% of the mass of the concrete material is needed;

[0017] 3) With the mixer, make sure the dispersion is uniform; or add after the aggregate is added, avoid direct contact with dry cement, and the stirring time is not less than 90 seconds;

[0018] 4) When the temperature is greater than 30℃, the content can be increased by 0.05%-0.1%, or 0.01%-0.03% sodium gluconate is compounded to enhance the effect of retarding; when the temperature is less than 5℃, the content is reduced by 0.05%-0.1%, to avoid excessive delay of setting; use ≤40℃ warm water to dissolve the water reducing agent.

[0019] Reaction principle: under the conditions of reaction temperature 60℃ and pH 6-7, ethylene glycol monovinyl polyethylene glycol ether polyether macromonomer is used as the main chain, the double bond is activated under the oxygen atom to enhance the polymerization ability and shorten the whole polymerization reaction time, vinyl triethoxy silane provides the side chain, the chemical adsorption between the alkoxy in the silane molecule and the cement paste makes the mortar fluidity loss small over time; the silanol produced by the hydrolysis of silane interacts with the cement surface to generate C-S-H, shortens the cement hydration induction period, and improves the dispersion ability and dispersion retention of the water reducing agent. Acrylic acid provides carboxyl groups to enhance the polymerization ability of the main chain; the polymerization reaction is initiated by hydrogen peroxide, 3-mercaptopropionic acid is used as a chain transfer agent, and ascorbic acid is used as a reducing agent to cooperate with hydrogen peroxide to initiate the reaction. 2-acrylamide-2-methylpropane sulfonic acid provides strong hydration ability and salt resistance through the sulfonic acid group (-SO3H) and amide group (-CONH2), and can still maintain dispersibility in the presence of clay, improves the retarding effect; the amide group enhances the adsorption ability of the polymer to the cement particles, itaconic acid can increase the crosslinking density of the polymer chain and improve the stability of the molecular structure by virtue of the dual-functionality of the double carboxyl groups, and further enhances the adsorption to the cement; NaOH is used to adjust the pH in the neutral range to ensure that the monomers participate in the reaction in the appropriate ionized state. 2+

[0020]

[0021] The beneficial effects of the present application are:

[0022] (1) By introducing vinyl triethoxy silane, the molecular structure is optimized. The present application is different from the traditional polycarboxylic acid water reducing agent which uses four or five carbon macromonomer under the condition of temperature generally at 60-80℃, the present product uses ethylene glycol monovinyl polyethylene glycol ether as macromonomer, which greatly shortens the reaction time, which can be completed within two hours at room temperature. Compared with the non-silane modified polycarboxylic acid water reducing agent, the silane modified polycarboxylic acid water reducing agent can significantly improve the workability and sulfate resistance of the water reducing agent, and is suitable for high performance and ultra-high performance concrete.

[0023] ​(2) Endowed with excellent slow-release performance of water-reducing agent. In alkaline environment, the sulfonic acid group and amide group of 2-acrylamide-2-methylpropane sulfonic acid and the carboxyl group of itaconic acid have strong electronegativity, and the sulfonic acid group is adsorbed on the surface of cement particles by electrostatic action, and the amide group can form hydrogen bonds with water molecules or the hydroxyl group on the surface of cement particles, increase the solution viscosity, slow down the ion diffusion rate, and thus delay the setting time. This property is particularly suitable for engineering applications such as road concrete that require long construction time, and solves the problem of short action time and rapid loss of slump of traditional water-reducing agents. 2+

[0024] (3) Excellent environmental adaptability. Through molecular design, the product can maintain stable performance under high temperature conditions, overcoming the defect that conventional water-reducing agents are prone to failure under high temperature environment. At the same time, the introduction of silane group enhances the anti-mud performance of the water-reducing agent, so that it can still maintain good workability under the condition of high mud content of aggregate, greatly expanding the application range.

[0025] (4) Optimal balance between performance and cost. Using one-step free radical polymerization process, the introduction of functional monomers and polymerization reaction are completed synchronously, avoiding complex post-modification steps and significantly reducing production cost. At the same time, the high performance of the product reduces the unit dosage, which overall reduces the engineering cost.

[0026] (5) In line with the development trend of green building materials. The product does not contain harmful substances such as chloride ions and heavy metals, and is friendly to the environment. Its excellent durability can also prolong the service life of concrete structures and reduce maintenance costs, with significant economic and social benefits. This integrated design of slow-release polycarboxylate superplasticizer can not only delay the early hydration of concrete through functional groups, but also maintain the slump stability by relying on long side chain polyether, thereby meeting the comprehensive needs of durability, crack resistance and long construction window of road concrete while reducing process cost, and conforming to the development trend of green building materials and long-life engineering. DETAILED DESCRIPTION

[0027] The technical solutions of the present application and their effects will be further described below in conjunction with the embodiments of the present application. The following examples are only used to illustrate the content of the present application and do not limit the protection scope of the present application. Simple changes made by applying the concept of the present application to the present application are within the scope of protection claimed by the present application.

[0028] The sources of the materials in the following examples and comparative examples are as follows:

[0029] Ethylene glycol monovinyl polyethylene glycol ether (EPEG): Liaoning Kelong Fine Chemical Co., Ltd.;

[0030] Acrylic acid (AA): Shanghai Aladdin Biological Technology Co., Ltd.; ​

[0031] Mercaptopropionic acid (MPA): Shanghai Aladdin Bio-Science Co., Ltd.

[0032] Ascorbic acid (Vc): Shanghai Aladdin Bio-Science Co., Ltd.

[0033] Hydrogen peroxide (H2O2): Tianjin Guangcheng Science and Technology Co., Ltd.

[0034] Sodium hydroxide (NaOH): Tianjin Guangcheng Science and Technology Co., Ltd.

[0035] Examples 1-5, Comparative Examples 1-4 all use the synthesis method of the slow-release polycarboxylate superplasticizer for road concrete in the invention content.

[0036] Example 1

[0037] 1) Mix acrylic acid and vinyl triethoxysilane in a molar ratio of 1:0.097, and dissolve in deionized water to obtain A solution with a solute mass fraction of 75%;

[0038] 2) Mix 0.05% 3-mercaptopropionic acid and 0.02% ascorbic acid based on the total system, and dissolve in deionized water to obtain B solution with a solute mass fraction of 15%;

[0039] 3) Put ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropane sulfonic acid, and itaconic acid in a molar ratio of 0.251:0.185:0.061 and an appropriate amount of deionized water into a 250 mL reactor with stirring function, stir at 60°C with a stirring speed of 60 r / min until the ethylene glycol monovinyl polyethylene glycol ether is completely dissolved; at this time, add a 30% mass fraction H2O2 solution, continue stirring for 15 min, and simultaneously add A solution obtained in 1) and B solution obtained in 2) at a constant speed, continue stirring for 1 h after dropping, and keep at 60°C for 3 h to obtain a preliminary product;

[0040] 4) Add a 30% mass fraction NaOH aqueous solution to the preliminary product obtained in step 3) to adjust the pH value to 6-7 to obtain the final product.

[0041] Example 2

[0042] 1) Mix acrylic acid and vinyl triethoxysilane in a molar ratio of 1:0.022, and dissolve in deionized water to obtain A solution with a solute mass fraction of 70%;

[0043] 2) Mix 0.01% 3-mercaptopropionic acid and 0.01% ascorbic acid based on the total system, and dissolve in deionized water to obtain B solution with a solute mass fraction of 10%;

[0044] 3) Put ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropane sulfonic acid, itaconic acid in a 250 mL reactor with stirring function in a molar ratio of 0.178:0.033:0.044 and an appropriate amount of deionized water, stir at 60°C, the stirring speed is 60 r / min, until the ethylene glycol monovinyl polyethylene glycol ether is completely dissolved; At this time, add a 30% H2O2 solution, continue to stir for 15 min, and add the A solution obtained in 1) and the B solution obtained in 2) at a uniform speed, continue to add for 1 h, continue to stir after adding, and incubate at 60°C for 3 h to obtain a preliminary product;

[0045] 4) Add a 30% NaOH aqueous solution to the preliminary product obtained in step 3) to adjust the pH value to 6-7 to obtain a final product.

[0046] Example 3

[0047] 1) Mix acrylic acid and vinyl triethoxysilane in a molar ratio of 1:0.216, and dissolve in deionized water to obtain an A solution with a solute mass fraction of 80%;

[0048] 2) Mix 0.08% 3-mercaptopropionic acid and 0.03% ascorbic acid based on the total system, and dissolve in deionized water to obtain a B solution with a solute mass fraction of 15%;

[0049] 3) Put ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropane sulfonic acid, itaconic acid in a 250 mL reactor with stirring function in a molar ratio of 0.324:0.338:0.081 and an appropriate amount of deionized water, stir at 60°C, the stirring speed is 60 r / min, until the ethylene glycol monovinyl polyethylene glycol ether is completely dissolved; At this time, add a 30% H2O2 solution, continue to stir for 15 min, and add the A solution obtained in 1) and the B solution obtained in 2) at a uniform speed, continue to add for 1 h, continue to stir after adding, and incubate at 60°C for 3 h to obtain a preliminary product;

[0050] 4) Add a 30% NaOH aqueous solution to the preliminary product obtained in step 3) to adjust the pH value to 6-7 to obtain a final product.

[0051] Example 4

[0052] Compared with Examples 1-3, the difference of Example 4 is that the raw material ratio is changed: acrylic acid and vinyl triethoxysilane are mixed in a molar ratio of 1:0.022, 3-mercaptopropionic acid and ascorbic acid are mixed into a solution with a mass fraction of 10%, and ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropane sulfonic acid, and itaconic acid are mixed in a ratio of 0.178:0.338:0.044.

[0053] Example 5

[0054] Example 5 differs from Examples 1-3 in that the raw materials are mixed in the following proportions: acrylic acid, vinyl triethoxysilane in a 1 :0.216 ratio, 3-mercaptopropionic acid, ascorbic acid in a 10% by mass solution, ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamido-2-methylpropane sulfonic acid, itaconic acid in a 0.324:0.033:0.081 ratio.

[0055] Comparative Example 1

[0056] Essentially the same as Example 1, except that acrylic acid is not used.

[0057] Comparative Example 2

[0058] Essentially the same as Example 1, except that vinyl triethoxysilane is not used.

[0059] Comparative Example 3

[0060] Essentially the same as Example 1, except that 2-acrylamido-2-methylpropane sulfonic acid, itaconic acid are not used.

[0061] Comparative Example 4

[0062] Essentially the same as Example 1, except that acrylic acid, vinyl triethoxysilane, 2-acrylamido-2-methylpropane sulfonic acid, itaconic acid are not used.

[0063] Examples 1-5, Comparative Examples 1-4 were all tested as follows:

[0064] 1. Verification of Retardation Performance

[0065] 1) Adsorption Kinetics Test (TOC Method)

[0066] The prepared product was mixed into cement at the specified ratio at 25°C and 40°C. Samples were taken at 0.5h / 1h / 2h / 4h, centrifuged (4000rpm, 5min) and the supernatant was used to determine the residual concentration of water reducer in the supernatant using a TOC analyzer. The adsorption amount (mg / g cement) was determined.

[0067] 2) Zeta Potential Monitoring

[0068] The initial potential was measured immediately after the addition of the water reducer (t=0), and then the zeta potential of the cement paste was tested every 15 min at 25°C and 40°C for 1h, and the change in potential was recorded.

[0069] 2. High Temperature Adaptability Test

[0070] 1) Slump Retention

[0071] According to GB / T 50080-2016, simulate high temperature construction, test the initial slump (S0) of concrete under the condition of temperature 35℃ and air humidity 60%, then retest every 30min (S t ), calculate the loss rate.

[0072] Loss rate (%) = (S 0- S t ) / S0x100%

[0073] 3. Anti-mud performance test

[0074] 1) Clay adsorption experiment

[0075] In the cement paste containing 5% bentonite, the adsorption amount of water reducing agent (TOC method) was determined, the mixed sample was centrifuged (4000rpm, 5min) to take the supernatant, the residual concentration of water reducing agent in the supernatant was determined by using TOC analyzer, and the adsorption amount (mg / g) was calculated.

[0076] Adsorption amount (mg / g) = (C o -C v ) x V / m 黏土

[0077] 2) Flow retention rate

[0078] According to GB / T 8077-2012, test the initial flow of cement paste containing clay (D0, mm) and the retention value after 30min (D 30 , mm), calculate the retention rate:

[0079] Retention rate (%) = D 30 / D0x100%

[0080] 4. Durability verification

[0081] 1) Test impermeability and shrinkage rate: according to GB / T 50082-2009, conduct chloride ion permeability test (RCM method) to determine the chloride ion migration coefficient (D nss , x10 -12 m 2 / s), determine the 28d dry shrinkage rate, and verify whether the silane modification inhibits cracks.

[0082] All performance tests were conducted on examples 1-5 and the control group, and the test results are shown in Table 1

[0083] Table 1 Performance test of examples 1-5

[0084]

[0085] The data in the table shows that the performance of the slow-release polycarboxylate superplasticizer for road concrete in Example 1 is the best, and the data is improved by 17.9%, 50.0%, 37.3%, 47.1%, 23.6%, 58.3%, 83.3%, and 178.9%, respectively. Among them, the adsorption stability of Example 1 and Example 5 at high temperature (40°C) is better (3.6 and 3.2 mg / g), which is suitable for high temperature environment, indicating that silane modification has a great improvement on the strength of concrete; the zeta potential of Example 1 is the lowest (-28.5 mV), indicating that its electrostatic repulsion is the strongest and the dispersion performance is the best. Example 1 has the best comprehensive performance: low slump loss rate (15.9%), lowest chloride ion permeability (3.5 x 10 -12 m 2 / s), and good construction and durability.

[0086] Table 2: Performance test of Comparative Examples 1-4 and Example 1

[0087]

[0088] As shown in Table 2, the performance of Comparative Examples 1-4 is weaker than that of Example 1, and the difference between Comparative Examples 3-4 and Example 1 is significant, especially the adaptability to high temperature and durability of Comparative Example 4 is much worse, and the retarding performance of Comparative Example 3 is greatly weakened, indicating that 2-acrylamide-2-methylpropanesulfonic acid and itaconic acid play an indispensable role in retarding function; there is a slight difference between Example 1 and Comparative Example 1, mainly in adsorption performance, indicating that acrylic acid plays a certain role in retarding performance; there is a great difference in strength between Comparative Example 2 and Example 1, indicating that silane modification is the key to the performance of concrete;

[0089] Example 6

[0090] According to the above test results, the product obtained in Example 1 is applied in road concrete, including the following steps:

[0091] 1) Storage: store in a cool and dry place, preferably at 5-30°C, avoid direct sunlight, and the shelf life is usually 6-12 months. Regularly check the uniformity of the liquid, and stir if there is stratification; the solid content is about 35-45%, and the pH value is between 6-7;

[0092] 2) If conventional concrete is prepared, 0.15%-0.3% of the mass of concrete materials is needed; if high-strength and durable concrete is needed: 0.25%-0.4% of the mass of concrete materials is needed;

[0093] 3) Add to the mixer simultaneously with the mixing water to ensure uniform dispersion; or add after the aggregate is added and before the cement is added, to avoid direct contact with dry cement, and the stirring time is not less than 90 seconds;

[0094] 4) Temperature greater than 30 ℃, the amount can be increased by 0.05%-0.1%, or compounded 0.01%-0.03% sodium gluconate to enhance the effect of retardation; Temperature less than 5 ℃, the amount is reduced by 0.05%-0.1%, to avoid excessive delay coagulation; Using ≤40 ℃ water to dissolve water reducing agent.

[0095] The above examples are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for preparing a slow-release polycarboxylate superplasticizer for road concrete, characterized in that, Includes the following steps: 1) Mix acrylic acid and vinyltriethoxysilane in a certain proportion and dissolve in deionized water to obtain solution A with a solute mass fraction of 70%-80%; 2) Mix 3-mercaptopropionic acid and ascorbic acid in a certain proportion and dissolve in deionized water to obtain solution B with a solute mass fraction of 10%-20%; 3) Place ethylene glycol monovinyl polyethylene glycol ether, 2-acrylamide-2-methylpropanesulfonic acid, itaconic acid, and an appropriate amount of deionized water into a 250 mL reactor equipped with a stirrer. Stir at 60 °C and 60 r / min until the ethylene glycol monovinyl polyethylene glycol ether is completely dissolved. At this point, add a 30% (w / w) H2O2 solution and continue stirring for 15 min. Simultaneously, add solution A obtained in 1) and solution B obtained in 2) dropwise at a uniform rate for 1 h. After the addition, continue stirring and keep the mixture at 60 °C for 3 h to obtain the preliminary product. 4) Add a 30% NaOH aqueous solution to the preliminary product obtained in step 3), adjust the pH value to 6-7, and obtain the final product.

2. The method for preparing a slow-release polycarboxylate superplasticizer for road concrete according to claim 1, characterized in that, The molar ratio of the raw materials used is: acrylic acid: vinyltriethoxysilane: ethylene glycol monovinyl polyethylene glycol ether: 2-acrylamide-2-methylpropanesulfonic acid: itaconic acid = 1: (0.022-0.216): (0.178-0.324): (0.033-0.338): (0.044-0.081).

3. The method for preparing a slow-release polycarboxylate superplasticizer for road concrete according to claim 1, characterized in that, The 3-mercaptopropionic acid accounts for 0.01%-0.09% of the total amount of the system in 3), and the ascorbic acid accounts for 0.01%-0.03% of the total amount of the system in 3).

4. The method for preparing a slow-release polycarboxylate superplasticizer for road concrete according to claim 1, characterized in that, The H2O2 used in 3) has a mass fraction of 30% and accounts for 0.4%-0.12% of the total amount of the system in 3).

5. The method for preparing a slow-release polycarboxylate superplasticizer for road concrete according to claim 1, characterized in that, The solid content of the final product is 35%-45%.

6. The slow-release polycarboxylate superplasticizer for road concrete prepared by any of the preparation methods described in claims 1-4.

7. The application of the slow-release polycarboxylate superplasticizer for road concrete according to claim 1 in road construction cement, characterized in that, Includes the following steps: 1) Storage: Store in a sealed container in a cool, dry place, ideally between 5-30℃. Avoid direct sunlight. Shelf life is typically 6-12 months. Regularly check the liquid's homogeneity; if separation occurs, stir until completely mixed. Solid content is approximately 40%, and pH is between 6 and 7. 2) If preparing conventional concrete, 0.15%-0.3% of the concrete material mass is required; if high-strength and durable concrete is required, 0.25%-0.4% of the concrete material mass is required. 3) Add the aggregate to the mixer simultaneously with the mixing water to ensure uniform dispersion; or add it after the aggregate is added and before the cement is added to avoid direct contact with dry cement. The mixing time should not be less than 90 seconds. 4) When the temperature is above 30℃, the dosage can be increased by 0.05%-0.1%, or 0.01%-0.03% sodium gluconate can be added to enhance the retarding effect; when the temperature is below 5℃, the dosage can be reduced by 0.05%-0.1% to avoid excessive delay in setting; use warm water at ≤40℃ to dissolve the water-reducing agent.

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