A concrete viscosity reducer and a preparation method thereof

Abstract

The application provides a concrete viscosity reducer and a preparation method thereof. The concrete viscosity reducer is prepared from sorbitol polyoxyethylene ether, glycerol polyoxyethylene ether, di-phosphorus pentoxide and a sodium hydroxide solution, wherein the molar ratio of the sorbitol polyoxyethylene ether to the glycerol polyoxyethylene ether is 1:2-5, the molar ratio of the sum of the hydroxyl moles of the sorbitol polyoxyethylene ether and the glycerol polyoxyethylene ether to the di-phosphorus pentoxide is 2:1, and the mass concentration of the sodium hydroxide solution is 30%. The organic phosphate ester salt prepared by the application is used as the concrete viscosity reducer in combination with the polycarboxylic acid water reducing agent, the time for completely emptying the slump of the concrete mixture is saved by more than 25%, the workability of the concrete is significantly improved, and the application has the characteristics of simple process, high safety, small energy consumption and low production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a concrete admixture, in particular to a UHPC concrete viscosity reducer and a preparation method thereof. BACKGROUND

[0002] With the construction of national infrastructure projects, the application of high-strength concrete is increasing. In order to meet the requirements of high-strength concrete, the water-cement ratio of concrete must be low, but the viscosity of concrete increases after the water-cement ratio is low, which can cause a series of problems such as difficult mixing and difficult pumping. Therefore, it is increasingly urgent to solve the problem of reducing the viscosity of concrete, and it is inevitable to find a new method for reducing viscosity. SUMMARY

[0003] The present application aims to provide a concrete viscosity reducer and a preparation method thereof to overcome the shortcomings of existing products and technologies. The viscosity reducer is prepared from sorbitol polyoxyethylene ether, glycerol polyoxyethylene ether, phosphorus pentoxide and sodium hydroxide solution.

[0004] Preferably, the molar ratio of sorbitol polyoxyethylene ether to glycerol polyoxyethylene ether is 1:2-5, and the molar ratio of the sum of the hydroxyl groups of sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether to phosphorus pentoxide is 2:1, and the mass concentration of sodium hydroxide solution is 30%.

[0005] Preferably, the ethoxylated degree of sorbitol polyoxyethylene ether is an integer in the range of 60-100.

[0006] Preferably, the ethoxylated degree of glycerol polyoxyethylene ether is an integer in the range of 20-50.

[0007] Preferably, the molar ratio of sorbitol polyoxyethylene ether to glycerol polyoxyethylene ether is 1:3-4.

[0008] The present application also provides a preparation method of a concrete viscosity reducer, comprising the following steps:

[0009] (1) Put sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether with a molar ratio of 1:2-5 into an enamel kettle, stir, and add phosphorus pentoxide in batches every 10 minutes while stirring at 25-40℃ for 1-2 hours, then perform phosphoric acid esterification reaction at 30-40℃ for 2 hours, and then heat to 50-80℃ for 3-4 hours; wherein the molar ratio of the sum of the hydroxyl groups of sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether to phosphorus pentoxide is 2:1; and nitrogen is continuously supplied into the enamel kettle for nitrogen protection during the whole reaction process;

[0010] (2) Neutralize the product obtained after the temperature holding in step (1) with a 30% mass concentration sodium hydroxide solution, the neutralization temperature is 60-80℃, and the neutralization is performed until the pH value is 6.0-8.0 to obtain a concrete viscosity reducer.

[0011] The sorbitol polyoxyethylene ether is denoted as SEO-m, m is the ethoxy polymerization degree, wherein m is an integer in 60-100.

[0012] The glycerol polyoxyethylene ether is denoted as EG-n, n is the ethoxy polymerization degree, wherein n is an integer in 20-50.

[0013] The concrete viscosity reducer is used in combination with the polycarboxylic acid water reducing agent, so that the time for completely emptying the slump cone of the concrete mixture is saved by more than 25%.

[0014] Compared with the prior products and technologies, the technical scheme of the present application has the following beneficial effects:

[0015] (1) The organic phosphate ester salt is prepared by esterification reaction of the above two polyol polyethers and phosphorus pentoxide, and is used as the concrete viscosity reducer in combination with the polycarboxylic acid water reducing agent, so that the time for completely emptying the slump cone of the concrete mixture is saved by more than 25%, and the workability of the concrete is significantly improved.

[0016] (2) The present application has the characteristics of simple process, high safety, small energy consumption and low production cost. DETAILED DESCRIPTION

[0017] The technical scheme in the present application will be clearly and completely described below in combination with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application. If no other description is given, the raw materials used are commercially available.

[0018] Embodiment 1

[0019] (1) A mixture of 1 mole of sorbitol polyoxyethylene ether with an ethoxy polymerization degree of 60 (SEO-60) and 3 moles of glycerol polyoxyethylene ether with an ethoxy polymerization degree of 40 (EG-40) is put into an enamel kettle, stirred, and 7.5 moles of phosphorus pentoxide is slowly added in batches every 10 minutes, the temperature of the material is controlled at 30℃, and the feeding time is 2 hours; after the feeding is completed, the reaction is carried out at 40℃ for 2 hours, and then the temperature is increased to 70℃ for 3.5 hours of heat preservation; during the whole reaction process, nitrogen is continuously supplied into the enamel kettle for nitrogen protection;

[0020] (2) The product obtained after the heat preservation in step (1) is neutralized by adding a 30% mass concentration sodium hydroxide solution, the neutralization temperature is 70℃, and the neutralization is carried out until the pH value is 6.0-8.0 to obtain the concrete viscosity reducer.

[0021] Embodiment 2

[0022] (1) Add 1 mole of sorbitol polyoxyethylene ether (SEO-70) with a degree of polymerization of 70 and 4 moles of glycerol polyoxyethylene ether (EG-30) with a degree of polymerization of 30 to an enamel-lined reactor, stir, and slowly add a total of 9 moles of phosphorus pentoxide in batches every 10 minutes, controlling the material temperature at 35°C, and the addition time is 1.5 hours; after the addition is complete, react at 35°C for 2 hours, and then raise the temperature to 50°C and keep it at that temperature for 4 hours; throughout the entire reaction process, nitrogen gas is continuously purged into the enamel-lined reactor for nitrogen protection;

[0023] (2) Add a 30% sodium hydroxide solution to the product obtained after the heat preservation in step (1) to neutralize it. The neutralization temperature is 65℃, and the pH value is neutralized to 6.0-8.0 to obtain a concrete viscosity reducer.

[0024] Example 3

[0025] (1) Add 1 mole of sorbitol polyoxyethylene ether (SEO-80) with a degree of polymerization of 80 and 3.5 moles of glycerol polyoxyethylene ether (EG-25) with a degree of polymerization of 25 to an enamel-lined reactor, stir, and slowly add a total of 8.25 moles of phosphorus pentoxide in batches every 10 minutes, controlling the material temperature at 25°C, and the addition time is 2 hours; after the addition is complete, react at 30°C for 2 hours, and then raise the temperature to 80°C and keep it at that temperature for 3 hours; throughout the entire reaction process, nitrogen gas is continuously purged into the enamel-lined reactor for nitrogen protection;

[0026] (2) Add a 30% sodium hydroxide solution to the product obtained after the heat preservation in step (1) to neutralize it. The neutralization temperature is 80℃, and the pH value is neutralized to 6.0-8.0 to obtain a concrete viscosity reducer.

[0027] Example 4

[0028] (1) Add 1 mole of sorbitol polyoxyethylene ether (SEO-90) with a degree of polymerization of 90 and 4.4 moles of glycerol polyoxyethylene ether (EG-50) with a degree of polymerization of 50 to an enamel-lined reactor, stir, and slowly add a total of 9.6 moles of phosphorus pentoxide in batches every 10 minutes, controlling the material temperature at 40°C, and the addition time is 1 hour; after the addition is complete, react at 40°C for 2 hours, and then raise the temperature to 60°C and keep it at that temperature for 4 hours; throughout the entire reaction process, nitrogen gas is continuously purged into the enamel-lined reactor for nitrogen protection;

[0029] (2) Add a 30% sodium hydroxide solution to the product obtained after the heat preservation in step (1) to neutralize it. The neutralization temperature is 75℃, and the pH value is neutralized to 6.0-8.0 to obtain a concrete viscosity reducer.

[0030] Example 5

[0031] (1) Add 1 mole of sorbitol polyoxyethylene ether (SEO-100) with a degree of polymerization of 100 and 2 moles of glycerol polyoxyethylene ether (EG-20) with a degree of polymerization of 20 to an enamel-lined reactor, stir, and slowly add a total of 6 moles of phosphorus pentoxide in batches every 10 minutes, controlling the material temperature at 35°C, and the addition time is 1.5 hours; after the addition is complete, react at 35°C for 2 hours, and then raise the temperature to 65°C and keep it at that temperature for 3.5 hours; throughout the entire reaction process, continuously purge the enamel-lined reactor with nitrogen for nitrogen protection;

[0032] (2) Add 30% sodium hydroxide solution to the product obtained after heat preservation in step (1) to neutralize it. The neutralization temperature is 60℃. Neutralize to pH value of 6.0 to 8.0 to obtain concrete viscosity reducer.

[0033] Example 6

[0034] (1) Add 1 mole of sorbitol polyoxyethylene ether (SEO-88) with a degree of polymerization of 88 and 5 moles of glycerol polyoxyethylene ether (EG-33) with a degree of polymerization of 33 to an enamel-lined reactor, stir, and slowly add a total of 10.5 moles of phosphorus pentoxide in batches every 10 minutes, controlling the material temperature at 25°C, and the addition time is 2 hours; after the addition is complete, react at 30°C for 2 hours, and then raise the temperature to 55°C and keep it at that temperature for 4 hours; throughout the entire reaction process, continuously purge the enamel-lined reactor with nitrogen for nitrogen protection;

[0035] (2) Add a 30% sodium hydroxide solution to the product obtained after the heat preservation in step (1) to neutralize it. The neutralization temperature is 70℃. Neutralize to pH value of 6.0 to 8.0 to obtain concrete viscosity reducer.

[0036] The concrete viscosity reducers prepared in Examples 1 to 6 of this invention were subjected to application performance tests. The amounts of each concrete material used in the test are shown in Table 1.

[0037] Table 1. Mix proportions of C80 concrete (kg / m³) 3 )

[0038] Water Cement Fly ash Slag Silica fume Sand Stone Water reducing agent 154 448 64 96 32 662 994 9.6

[0039] When preparing concrete with a viscosity reducer, the dosage of the viscosity reducer is 0.25% of the binder. Concrete viscosity is evaluated by the time it takes for the concrete mixture to completely empty in an inverted slump cone, according to GB / T50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures". The specific method is as follows: invert the slump cone on a support, with the bottom 50cm off the ground, seal the bottom, fill it with concrete as required and smooth it, open the sealed cover, and use a stopwatch to measure the time it takes for the concrete mixture to completely empty. Concrete compressive strength is tested according to GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". Comparative test performance is shown in Performance Comparison Test Table 2.

[0040] Table 2 Performance Comparison Test Table

[0041]

[0042]

[0043] Note: The comparative example is a blank sample without water-reducing agent or viscosity reducer. The water-reducing agent is FOX RX-1-320 (20% solids content) from FOX Corporation.

[0044] The test results show that, under the same concrete mix proportion, the voiding time of the control sample without concrete viscosity reducer was 9.1s, while the fluidity of the concrete with viscosity reducer was significantly improved, the voiding time was shortened by at least 2.6s, and the compressive strength of the concrete at all ages was slightly increased.

Claims

1. A concrete viscosity reducer, characterized in that, The viscosity reducer is prepared from sorbitol polyoxyethylene ether, glycerol polyoxyethylene ether, phosphorus pentoxide and sodium hydroxide solution; the molar ratio of sorbitol polyoxyethylene ether to glycerol polyoxyethylene ether is 1:2 to 5, the molar ratio of the sum of the molar numbers of hydroxyl groups of sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether to phosphorus pentoxide is 2:1, and the mass concentration of sodium hydroxide solution is 30%.

2. The concrete viscosity reducer according to claim 1, characterized in that, The degree of ethoxylation of the sorbitol polyoxyethylene ether is an integer from 60 to 100.

3. The concrete viscosity reducer according to claim 1, characterized in that, The degree of ethoxylation of the glycerol polyoxyethylene ether is an integer between 20 and 50.

4. The concrete viscosity reducer according to claim 1, characterized in that, The molar ratio of sorbitol polyoxyethylene ether to glycerol polyoxyethylene ether is 1:3-4.

5. The method for preparing the concrete viscosity reducer according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether are added to an enamel-lined reactor in a molar ratio of 1:2 to 5. The mixture is stirred and added in batches every 10 minutes at 25 to 40°C for 1 to 2 hours while stirring. After the addition is complete, the mixture is subjected to a phosphoric acid esterification reaction at 30 to 40°C for 2 hours. Then the temperature is raised to 50 to 80°C and the reaction is maintained for 3 to 4 hours. The molar ratio of the sum of the hydroxyl moles of sorbitol polyoxyethylene ether and glycerol polyoxyethylene ether to phosphorus pentoxide is 2:

1. During the entire reaction, nitrogen gas is continuously introduced into the enamel-lined reactor for nitrogen protection. The degree of polymerization of sorbitol polyoxyethylene ether is an integer between 60 and 100, and the degree of polymerization of glycerol polyoxyethylene ether is an integer between 20 and 50. (2) Add a 30% sodium hydroxide solution to the product obtained after the heat preservation in step (1) to neutralize it. The neutralization temperature is 60-80℃, and the pH value is neutralized to 6.0-8.0 to obtain a concrete viscosity reducer.

6. The concrete viscosity reducer according to any one of claims 1 to 5, wherein the concrete viscosity reducer is used in combination with polycarboxylate superplasticizer, thereby reducing the time required for the concrete mixture to completely empty in the slump drum by more than 25%.

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