Low-temperature retarding material additive and preparation method thereof

Abstract

The invention relates to a low-temperature retarding material additive and a preparation method thereof, and belongs to the technical field of retarding material additives. The low-temperature retarding material additive is mainly prepared from the following components in parts by weight: 3 to 5 parts of gamma-polyglutamic acid, 4 to 6 parts of sodium monofluorophosphate, 8 to 12 parts of trimethylolethane, 2 to 4 parts of Na3PO4, 12 to 15 parts of sodium carboxymethyl cellulose, 8 to 10 parts of silica sol, 5 to 7 parts of modified polysaccharide, 3 to 4 parts of polyvinylpyrrolidone and a water reducing agent. By adding the retarder, the slump and expansion loss of a concrete mixture can be reduced, the initial setting time is relatively prolonged, and the compressive strength of concrete can be basically unchanged.

Description

Technical Field

[0001] The present invention belongs to the technical field of retarder additives for setting retarder materials, and relates to a low-temperature retarder additive for setting retarder materials and a preparation method thereof. Background Art

[0002] A retarder is an admixture that can extend the setting time of concrete. It can be divided into two types according to performance: a retarder that only delays the setting time of concrete, and a retarding water reducer that combines the functions of retarding and water reducing. According to chemical composition, it can be divided into inorganic retarders and organic retarders. Inorganic retarders include: phosphates, zinc salts, ferric sulfate, copper sulfate, borates, fluorosilicates, etc. Organic retarders include; hydroxycarboxylic acids and their salts, polyols and their derivatives, sugars and carbohydrates, etc.

[0003] Most organic retarders have surface activity. They adsorb on the solid-liquid interface, and a large number of water molecules are adsorbed through the hydrophilic groups in their molecules to form a relatively thick water film layer, shielding the mutual contact between crystals and changing the structure formation process; or certain functional groups in their molecules react with free calcium ions to form insoluble calcium salts, which are adsorbed on the surface of mineral particles, thereby inhibiting the hydration process of cement. Most inorganic retarders can form double salts (such as ettringite) with the hydration products of cement and precipitate on the surface of cement mineral particles to inhibit cement hydration.

[0004] However, traditional cement retarders have good retardation effects at high temperatures, but their retardation effects are not obvious at low temperatures, and problems such as large dosage, obvious thickening of cement slurry, and great influence on the development of cement strength are likely to occur. Therefore, there is an urgent need to develop a retarder with good use effects at low temperatures. Summary of the Invention

[0005] The main purpose of the present invention is to provide a low-temperature retarder additive for setting retarder materials, which can still have good retardation effects under low-temperature conditions.

[0006] The present invention adopts the following technical solutions to achieve the above purpose:

[0007] A low-temperature retarder additive for setting retarder materials is mainly prepared from the following components in parts by weight:

[0008] 3-5 parts of γ-polyglutamic acid, 4-6 parts of sodium monofluorophosphate, 8-12 parts of trimethylolethane, Na 3 PO 4 2-4 parts, 12-15 parts of sodium carboxymethylcellulose, 8-10 parts of silica sol, 5-7 parts of modified polysaccharide, 3-4 parts of polyvinylpyrrolidone.

[0009] Preferably, the above low-temperature retarder additive for setting retarder materials may further contain 0.5-0.8 parts of a water reducer.

[0010] Further, the water reducing agent is preferably a polycarboxylate water reducing agent.

[0011] The preparation method of the modified polysaccharide includes the following steps:

[0012] Step a: Place γ-cyclodextrin in a tartaric acid solution with a mass fraction of 60-75%, heat it to 60-70°C in an anaerobic environment, keep it warm for 4-5 hours, and then dry it to obtain a mixture for later use;

[0013] Step b: Mix vinylsulfonic acid, sodium alginate, erythritol, and potassium peroxydiphosphate, heat it to 120-130°C in an inert atmosphere and keep it warm for 4-5 hours. After the reaction is completed, add the mixture obtained in step A and methyl hydrogenated rosin at this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0014] Preferably, in step A of the preparation method of the modified polysaccharide, the mass-volume ratio of γ-cyclodextrin to the tartaric acid solution is (0.5-0.8):1 in g / mL.

[0015] Preferably, in step B of the preparation method of the modified polysaccharide, the mass ratio of vinylsulfonic acid, sodium alginate, erythritol, potassium peroxydiphosphate, the mixture, and methyl hydrogenated rosin is 1:(10-15):(3-5):(0.1-0.15):(1-1.5):(0.5-0.8).

[0016] The preparation method of the low-temperature setting retarder additive includes the following steps:

[0017] Step A: Mix γ-polyglutamic acid, Na 3 PO 4 and silica sol, and then perform ultrasonic treatment to obtain a mixed solution for later use;

[0018] Step B: Add water to sodium carboxymethylcellulose and heat it to a viscous state, then add sodium monofluorophosphate and polyvinylpyrrolidone and mix well to obtain a mixture for later use;

[0019] Step C: Mix the mixed solution obtained in step A, the mixture obtained in step B, trimethylolethane, the modified polysaccharide, and the water reducing agent, and then dry to obtain the low-temperature setting retarder additive.

[0020] The present invention has the following beneficial effects:

[0021] Generally, the use of retarders can usually reduce the dry shrinkage of concrete, but the bleeding water volume and bleeding speed of concrete increase, which affects the quality of concrete projects. Adding silica sol has a great influence on the fluidity of fresh cement-based materials. When the dosage is relatively large, the viscosity of the paste is very high, showing shear thinning behavior and strong thixotropy. The reason is that the silica sol nanoparticles rapidly flocculate or gelate in the cement paste, and the flocs or gels not only cannot play a filling effect, but also contain a large amount of capillary water that makes no contribution to fluidity.

[0022] The coagulant of the present invention has a good retardation effect, and under low temperature conditions of 0°C and 5°C, it can reduce the slump and slump flow loss of the concrete mixture, relatively extend the initial setting time, and can ensure that the compressive strength of the concrete remains basically unchanged. Specific embodiments

[0023] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art fall within the scope protected by the claims of this application.

[0024] Example 1

[0025] Prepare modified polysaccharide:

[0026] Step a: Place 50 g of γ-cyclodextrin in 100 mL of tartaric acid solution with a mass fraction of 60%, heat it to 70°C in an anaerobic environment, keep it warm for 4 h, and then dry it to obtain a mixture for later use;

[0027] Step b: Mix 100 g of vinylsulfonic acid, 1000 g of sodium alginate, 500 g of erythritol, and 10 g of potassium peroxydiphosphate, heat it to 130°C in an inert atmosphere and keep it warm for 4 h. After the reaction is completed, add 100 g of the mixture obtained in step A and 80 g of methyl hydrogenated rosin ester under this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0028] Prepare an additive for low-temperature retardation materials:

[0029] Step A: Mix 3 g of γ-polyglutamic acid, 4 g of Na 3 PO 4 , and 8 parts of silica sol, and perform ultrasonic treatment to obtain a mixed solution for later use;

[0030] Step B: Add water to 12 g of sodium carboxymethylcellulose and heat it to a viscous state, add 6 g of sodium monofluorophosphate and 3 g of polyvinylpyrrolidone, and mix well to obtain a mixture for later use;

[0031] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 12 g of trimethylolethane, 5 g of modified polysaccharide, and 0.8 g of polycarboxylate superplasticizer, and then dry to obtain the low-temperature retarding material additive.

[0032] Example 2

[0033] Preparation of modified polysaccharide:

[0034] Step a: Place 80 g of γ-cyclodextrin in 100 mL of tartaric acid solution with a mass fraction of 75%, heat it to 60 °C in an anaerobic environment, keep it warm for 5 h, and then dry to obtain a mixture for standby.

[0035] Step b: Mix 100 g of vinylsulfonic acid, 1500 g of sodium alginate, 300 g of erythritol, and 15 g of potassium peroxydiphosphate, heat it to 120 °C in an inert atmosphere and keep it warm for 5 h. After the reaction is completed, add 150 g of the mixture obtained in Step A and 50 g of methyl hydrogenated rosin ester under this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0036] Preparation of low-temperature retarding material additive:

[0037] Step A: Mix 4 g of γ-polyglutamic acid, 3 g of Na 3 PO 4 , and 9 g of silica sol, and then perform ultrasonic treatment to obtain a mixed solution for standby.

[0038] Step B: Add water to 13 g of sodium carboxymethylcellulose and heat it to a viscous state, then add 5 g of sodium monofluorophosphate and 4 g of polyvinylpyrrolidone and mix well to obtain a mixture for standby.

[0039] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 10 g of trimethylolethane, 6 g of modified polysaccharide, and 0.6 g of polycarboxylate superplasticizer, and then dry to obtain the low-temperature retarding material additive.

[0040] Example 3

[0041] Preparation of modified polysaccharide:

[0042] Step a: Place 70 g of γ-cyclodextrin in 100 mL of tartaric acid solution with a mass fraction of 65%, heat it to 70 °C in an anaerobic environment, keep it warm for 4 h, and then dry to obtain a mixture for standby.

[0043] Step b: Mix 100 g of vinylsulfonic acid, 1400 g of sodium alginate, 400 g of erythritol, and 13 g of potassium peroxydiphosphate, heat it to 130 °C in an inert atmosphere and keep it warm for 4 h. After the reaction is completed, add 130 g of the mixture obtained in Step A and 70 g of methyl hydrogenated rosin ester under this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0044] Preparation of low-temperature retarding material additive:

[0045] Step A: Mix 5 g of γ-polyglutamic acid, 2 g of Na 3 PO 4 and 10 g of silica sol, and then perform ultrasonic treatment to obtain a mixed solution for standby;

[0046] Step B: Add water to 15 g of sodium carboxymethyl cellulose and heat it to a viscous state, then add 4 g of sodium monofluorophosphate and 4 g of polyvinylpyrrolidone and mix well to obtain a mixture for standby;

[0047] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 8 g of trimethylolethane, 7 g of modified polysaccharide, and 0.5 g of polycarboxylate superplasticizer, and then dry to obtain the low-temperature retarding material additive.

[0048] Example 4

[0049] Preparation of modified polysaccharide:

[0050] Step a: Place 60 g of γ-cyclodextrin in 100 mL of tartaric acid solution with a mass fraction of 65%, heat it to 60 °C in an anaerobic environment, keep it warm for 5 h, and then dry to obtain a mixture for standby;

[0051] Step b: Mix 100 g of vinylsulfonic acid, 1200 g of sodium alginate, 350 g of erythritol, and 11 g of potassium peroxydiphosphate, heat it to 120 °C in an inert atmosphere and keep it warm for 5 h. After the reaction is completed, add 140 g of the mixture obtained in Step A and 65 g of methyl hydrogenated rosin ester under this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0052] Preparation of low-temperature retarding material additive:

[0053] Step A: Mix 3 g of γ-polyglutamic acid, 3 g of Na 3 PO 4 and 9 g of silica sol, and then perform ultrasonic treatment to obtain a mixed solution for standby;

[0054] Step B: Add water to 14 g of sodium carboxymethyl cellulose and heat it to a viscous state, then add 5 g of sodium monofluorophosphate and 4 g of polyvinylpyrrolidone and mix well to obtain a mixture for standby;

[0055] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 11 g of trimethylolethane, and 6 g of modified polysaccharide, and then dry to obtain the low-temperature retarding material additive.

[0056] Comparative Example 1

[0057] Preparation of low-temperature retarding material additive:

[0058] Step A: Mix 5 g of γ-polyglutamic acid, 2 g of Na 3PO 4 After mixing with 10 g of silica sol, ultrasonic treatment is carried out to obtain a mixed solution for standby;

[0059] Step B: Add 15 g of sodium carboxymethyl cellulose to water and heat to a viscous state. Then add 4 g of sodium monofluorophosphate and 4 g of polyvinylpyrrolidone and mix well to obtain a mixture for standby;

[0060] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 8 g of trimethylolethane, 3 g of γ-cyclodextrin, 4 g of sodium alginate, and 0.5 g of polycarboxylate water reducer, and dry to obtain a low-temperature retarding material additive.

[0061] Comparative Example 2

[0062] Preparation of modified polysaccharide:

[0063] Mix 100 g of vinylsulfonic acid, 1400 g of sodium alginate, and 13 g of potassium peroxydiphosphate, heat to 130 °C in an inert atmosphere and keep warm for 4 h. After the reaction is completed, cool to room temperature to obtain the modified polysaccharide.

[0064] Preparation of low-temperature retarding material additive:

[0065] Step A: Mix 5 g of γ-polyglutamic acid, 2 g of Na 3 PO 4 After mixing with 10 g of silica sol, ultrasonic treatment is carried out to obtain a mixed solution for standby;

[0066] Step B: Add 15 g of sodium carboxymethyl cellulose to water and heat to a viscous state. Then add 4 g of sodium monofluorophosphate and 4 g of polyvinylpyrrolidone and mix well to obtain a mixture for standby;

[0067] Step C: Mix the mixed solution obtained in Step A, the mixture obtained in Step B, 8 g of trimethylolethane, 7 g of modified polysaccharide, and 0.5 g of polycarboxylate water reducer, and dry to obtain a low-temperature retarding material additive.

[0068] Comparative Example 3

[0069] Preparation of modified polysaccharide:

[0070] Mix 100 g of vinylsulfonic acid, 1400 g of sodium alginate, 400 g of erythritol, and 13 g of potassium peroxydiphosphate, heat to 130 °C in an inert atmosphere and keep warm for 4 h. After the reaction is completed, add 70 g of γ-cyclodextrin under this reaction condition, mix well, and cool to room temperature to obtain the modified polysaccharide.

[0071] Preparation of low-temperature retarding material additive:

[0072] Mix 5 g of γ-polyglutamic acid, 10 g of silica sol, 15 g of sodium carboxymethyl cellulose, 4 g of polyvinylpyrrolidone, 8 g of trimethylolethane, and 7 g of modified polysaccharide, and dry to obtain a low-temperature retarding material additive.

[0073] Performance test

[0074] Under the premise that the concrete mix ratio and the initial workability state of the mixture are similar, the effects of retarders on the slump, setting time, and compressive strength of the concrete mixture under low-temperature conditions of 0°C and 5°C and normal-temperature conditions of 20°C.

[0075] Results and analysis:

[0076] As can be seen from the results in Table 1, under the condition of 20°C, the effects of different retarders on the concrete mixture are not very different. The slump and spread loss are both below 40, the difference in the initial setting time is small, and the compressive strength is basically the same.

[0077] As can be seen from the results in Tables 2 and 3, under low-temperature conditions of 0°C and 5°C, the addition of the retarders of Examples 1-4 of the present invention can reduce the slump and spread loss of the concrete mixture, relatively extend the initial setting time, and can ensure that the compressive strength of the concrete remains basically unchanged; when using the coagulants of Comparative Examples 1-3, the spread loss is large, the initial setting time becomes shorter, and the compressive strength decreases.

[0078] Table 1 Effects of different retarders on concrete under 20°C low-temperature conditions

[0079]

[0080]

[0081] Table 2 Effects of different retarders on concrete under 5°C low-temperature conditions

[0082]

[0083] Table 3 Effects of different retarders on concrete under 0°C low-temperature conditions

[0084]

Claims

1. A low-temperature retarding material additive, characterized in that: It is prepared from the following ingredients in parts by weight: 3-5 parts of gamma-polyglutamic acid, 4-6 parts of sodium monofluorophosphate, 8-12 parts of trimethylolethane, 2-4 parts of Na3PO4, 12-15 parts of sodium carboxymethyl cellulose, 8-10 parts of silica sol, 5-7 parts of modified polysaccharide, and 3-4 parts of polyvinyl pyrrolidone.

2. The low temperature retarding material additive according to claim 1, characterized in that: The low-temperature retarding material additive also contains 0.5-0.8 parts of a water reducing agent.

3. The low temperature retarding material additive according to claim 2, characterized in that: The water reducer is a polycarboxylate water reducer.

4. The low temperature retarding material additive according to claim 3, characterized in that: The preparation method of the modified polysaccharide comprises the following steps: Step a, placing γ-cyclodextrin in a tartaric acid solution with a mass fraction of 60-75%, heating to 60-70° C. in an oxygen-free environment, keeping the temperature for 4-5 hours, and then drying to obtain a mixture for use; Step b, after mixing vinyl sulfonic acid, sodium alginate, erythritol and potassium perphosphate, heat to 120-130° C. in an inert atmosphere and keep warm for 4-5 hours. After the reaction is completed, add the mixture obtained in step A and hydrogenated rosin methyl ester under the reaction conditions, mix well, and cool to room temperature to obtain modified polysaccharide.

5. The low temperature retarding material additive according to claim 4, characterized in that: In step A of the modified polysaccharide preparation method, the mass-volume ratio of γ-cyclodextrin to tartaric acid solution is (0.5-0.8) in g / mL:

1.

6. The low temperature retarding material additive according to claim 4, characterized in that: In step B of the modified polysaccharide preparation method, the mass ratio of vinyl sulfonic acid, sodium alginate, erythritol, potassium perphosphate, mixture, and hydrogenated rosin methyl ester is 1:(10-15):(3-5):(0.1-0.15):(1-1.5):(0.5-0.8).

7. The low temperature retarding material additive according to claim 3, characterized in that: The preparation method of the low-temperature retarding material additive comprises the following steps: Step A, mixing γ-polyglutamic acid, Na3PO4 and silica sol and then ultrasonically treating the mixture to obtain a mixed solution for later use; Step B, adding water to sodium carboxymethyl cellulose and heating it until it becomes viscous, adding sodium monofluorophosphate and polyvinyl pyrrolidone and mixing well to obtain a mixture for later use; Step C, mixing the mixed solution obtained in step A, the mixture obtained in step B, trimethylolethane, modified polysaccharide and water reducing agent, and drying to obtain a low-temperature retarding material additive.

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