1. The water reducing agent is characterized by comprising the following raw material components: isopentene polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid;

the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3.

2. The water reducing agent according to claim 1, wherein the weight ratio of the isopentenyl polyoxyethylene ether to the hydrogen peroxide is 360: 2.5-3.

3. The water reducer according to claim 1, wherein the weight ratio of the isopentenyl polyoxyethylene ether, the ascorbic acid and the oxalic acid is 360:3: 1.5.

4. The water reducer of claim 1, characterized in that the water reducer comprises the following raw material components: 360 parts of isopentene polyoxyethylene ether, 26.5 parts of acrylic acid, 2.5 parts of hydrogen peroxide, 2 parts of ascorbic acid, 4.6 parts of sodium hypophosphite, 1.3 parts of anhydrous sodium sulfite and 2.5 parts of oxalic acid.

5. A method for preparing a water reducing agent according to any one of claims 1 to 4, characterized by comprising the steps of:

dissolving acrylic acid in water to prepare solution A;

adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B;

adding oxalic acid, sodium hypophosphite and hydrogen peroxide into an aqueous solution of isopentenyl polyoxyethylene ether, and stirring to obtain a mixed solution;

and dropwise adding the solution A and the solution B into the mixed solution, and stirring at normal temperature to react to obtain the water reducing agent.

6. The method for preparing a water reducing agent according to claim 5, wherein in the step of adding the solution A and the solution B dropwise to the mixed solution, and stirring the mixed solution at normal temperature to react to obtain the water reducing agent, the solution A and the solution B are added dropwise simultaneously.

7. The preparation method of the water reducer according to claim 6, wherein the dropping time of the solution A and the solution B is not more than 1 h.

8. The preparation method of the water reducer according to claim 6, wherein the reaction time is 0.8-1.5 h.

9. The preparation method of the water reducing agent according to claim 5, wherein the step of adding oxalic acid, sodium hypophosphite and hydrogen peroxide into the aqueous solution of the isopentenyl polyoxyethylene ether and stirring to obtain a mixed solution comprises the following steps:

stirring the water solution of the isopentenyl polyoxyethylene ether for 15-25 min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 8-12 min to obtain a mixed solution.

10. Concrete, characterized in that it comprises a water-reducing agent according to any one of claims 1 to 4.

Background

In recent years, the polycarboxylic acid high-performance water reducing agent is rapidly developed under the drive of high-speed railway construction. The water reducing agent promotes the development of new concrete technology in China, promotes the application of industrial byproducts in a cementing material system, and gradually becomes an essential material for high-quality concrete. The existing high-performance polycarboxylate superplasticizer needs to be heated up in the synthesis process, so that the time consumption is long due to the heating up of equipment, and the cost is high.

Disclosure of Invention

The invention mainly aims to provide a water reducing agent, a preparation method thereof and concrete, and aims to solve the problem that the conventional high-performance polycarboxylate water reducing agent needs to be heated up in the synthesis process.

In order to achieve the purpose, the invention provides a water reducing agent which comprises the following raw material components: isopentene polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid;

the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3.

Optionally, the weight ratio of the isopentenyl polyoxyethylene ether to the hydrogen peroxide is 360: 2.5-3.

Optionally, the weight ratio of the prenyl polyoxyethylene ether, the ascorbic acid, and the oxalic acid is 360:3: 1.5.

Optionally, the water reducing agent comprises the following raw material components: 360 parts of isopentene polyoxyethylene ether, 26.5 parts of acrylic acid, 2.5 parts of hydrogen peroxide, 2 parts of ascorbic acid, 4.6 parts of sodium hypophosphite, 1.3 parts of anhydrous sodium sulfite and 2.5 parts of oxalic acid.

In addition, the invention also provides a preparation method of the water reducing agent, which comprises the following steps:

dissolving acrylic acid in water to prepare solution A;

adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B;

adding oxalic acid, sodium hypophosphite and hydrogen peroxide into an aqueous solution of isopentenyl polyoxyethylene ether, and stirring to obtain a mixed solution;

and dropwise adding the solution A and the solution B into the mixed solution, and stirring at normal temperature to react to obtain the water reducing agent.

Optionally, in the step of dropwise adding the solution A and the solution B into the mixed solution, and stirring and reacting at normal temperature to obtain the water reducing agent, the solution A and the solution B are simultaneously dropwise added.

Optionally, the dropping time of the solution A and the solution B is not more than 1 h.

Optionally, the reaction time is 0.8-1.5 h.

Optionally, the step of adding oxalic acid, sodium hypophosphite and hydrogen peroxide into the aqueous solution of isopentenyl polyoxyethylene ether and stirring to obtain a mixed solution includes:

stirring the water solution of the isopentenyl polyoxyethylene ether for 15-25 min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 8-12 min to obtain a mixed solution.

In addition, the invention also provides concrete, which comprises a water reducing agent, wherein the water reducing agent comprises the following raw material components: isopentene polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid;

the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3.

In the technical scheme provided by the invention, isopentenyl polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid are selected as raw materials of the water reducer, and the use amount of each component is optimized, so that on one hand, the water reducer can maintain the heat balance of a reaction system by utilizing the heat released by a polymerization reaction in the production process, realize normal-temperature polymerization and low-temperature polymerization, and reduce energy consumption; on the other hand, the sensitivity can be reduced through the low-acid ether ratio, so that the water reducer can have better slump retentivity under the condition of keeping the original high water reducing rate, has better adaptability to other concrete materials of cement ground materials, is easier to start to slurry, improves the comprehensive performance of the water reducer, and meets the requirement of site concrete adaptation.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of an embodiment of a method for preparing a water reducing agent provided by the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In recent years, the polycarboxylic acid high-performance water reducing agent is rapidly developed under the drive of high-speed railway construction. The water reducing agent promotes the development of new concrete technology in China, promotes the application of industrial byproducts in a cementing material system, and gradually becomes an essential material for high-quality concrete. The existing high-performance polycarboxylate superplasticizer needs to be heated up in the synthesis process, so that the time consumption is long due to the heating up of equipment, and the cost is high.

In view of the above, the invention provides a water reducing agent which can be synthesized at normal temperature/low temperature, has good comprehensive performance, and can meet the adaptation requirement of on-site concrete. The water reducing agent comprises the following raw material components: isopentene polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid; the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3.

In the technical scheme provided by the invention, isopentenyl polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid are selected as raw materials of the water reducer, and the use amount of each component is optimized, so that on one hand, the water reducer can maintain the heat balance of a reaction system by utilizing the heat released by a polymerization reaction in the production process, realize normal-temperature polymerization and low-temperature polymerization, and reduce energy consumption; on the other hand, the sensitivity can be reduced through the low-acid ether ratio, so that the water reducer can have better slump retentivity under the condition of keeping the original high water reducing rate, has better adaptability to other concrete materials of cement ground materials, is easier to start to slurry, improves the comprehensive performance of the water reducer, and meets the requirement of site concrete adaptation.

Wherein the dosage of the pyruvic acid is preferably 7 to 10 weight percent of the dosage of the copolymerization macromonomer isopentenyl polyoxyethylene ether. When the addition amount of the pyruvic acid is in the range, the comb-shaped molecular structure obtained by copolymerization increases along with the addition amount of the pyruvic acid, the net slurry fluidity increases firstly and then decreases, and the obtained water reducing agent has better performance.

The addition of the hydrogen peroxide affects the performance of the water reducing agent. The test was carried out using the neat paste fluidity as an index and the hydrogen peroxide addition amount as an object, and the test results are shown in table 1 below. When the amount of hydrogen peroxide is too high, the amount of active species of radicals is large, resulting in low molecular weight and poor dispersibility. The invention optimizes the dosage of hydrogen peroxide, so that the weight ratio of the isopentenyl polyoxyethylene ether to the hydrogen peroxide in the formula of the water reducing agent is 360: 2.5-3, namely 2.5-3 parts of hydrogen peroxide is correspondingly added to every 360 parts of isopentenyl polyoxyethylene ether, and in the range, the net slurry fluidity is increased and then reduced along with the increase of the dosage of the hydrogen peroxide, and the dosage of the hydrogen peroxide is preferably 3.0 g.

TABLE 1 Effect of hydrogen peroxide addition on neat paste fluidity

In addition, the amount of reducing agent used can also have a significant effect on the overall redox system, which can release sufficient heat to maintain the desired heat balance of the reaction system. The test was carried out using the net slurry fluidity as an index and the amounts of ascorbic acid and oxalic acid added as objects, and the test results are shown in table 2 below. As can be seen from the table, when the weight ratio of the prenyl polyoxyethylene ether, the ascorbic acid and the oxalic acid is 360:3:1.5, that is, 3 parts of ascorbic acid and 1.5 parts of oxalic acid are added per 360 parts of prenyl polyoxyethylene ether, the net slurry fluidity is the best.

TABLE 2 Effect of ascorbic acid and oxalic acid addition on neat paste fluidity

As a preferred embodiment, in this embodiment, the water reducing agent comprises the following raw material components: 360 parts of isopentene polyoxyethylene ether, 26.5 parts of acrylic acid, 2.5 parts of hydrogen peroxide, 2 parts of ascorbic acid, 4.6 parts of sodium hypophosphite, 1.3 parts of anhydrous sodium sulfite and 2.5 parts of oxalic acid. Compared with other component ratios, the water reducer has the best comprehensive performance.

In addition, the invention also provides a preparation method of the water reducing agent, and fig. 1 is an embodiment of the preparation method of the water reducing agent provided by the invention.

Referring to fig. 1, the preparation method of the water reducing agent comprises the following steps:

step S10, dissolving acrylic acid in water to obtain solution A;

step S20, ascorbic acid and anhydrous sodium sulfite are added into water to prepare solution B;

and step S30, adding oxalic acid, sodium hypophosphite and hydrogen peroxide into the aqueous solution of the isopentenyl polyoxyethylene ether, and stirring to obtain a mixed solution.

In specific implementation, step S30 may be performed according to the following steps:

and step S31, stirring the water solution of the isopentenyl polyoxyethylene ether for 15-25 min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide into the water solution, and stirring for 8-12 min to obtain a mixed solution.

The method directly puts hydrogen peroxide into the bottom materials of the kettle, and then drops B and ascorbic acid as a reducing agent to directly react with the hydrogen peroxide to release a large amount of heat so as to maintain the heat balance of a reaction system, so that normal-temperature polymerization is realized without heating, the energy consumption is reduced, and compared with the conventional synthesis method, the method saves the time required by heating because the heating is not required (at present, the conventional synthesis process usually needs to consume at least two hours to heat to the required temperature), greatly shortens the synthesis time, and improves the production efficiency.

In addition, the addition amount of each component is as follows: the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3. And preferably 360 parts of isopentenyl polyoxyethylene ether, 26.5 parts of acrylic acid, 2.5 parts of hydrogen peroxide, 2 parts of ascorbic acid, 4.6 parts of sodium hypophosphite, 1.3 parts of anhydrous sodium sulfite and 2.5 parts of oxalic acid.

The method selects the isopentenyl polyoxyethylene ether, the acrylic acid, the hydrogen peroxide, the ascorbic acid, the sodium hypophosphite, the anhydrous sodium sulfite and the oxalic acid as the raw materials of the water reducer, optimizes the using amount of each component, not only can realize normal-temperature synthesis, but also can optimize the performance of the water reducer, so that the water reducer has better slump retentivity under the condition of keeping the original high water-reducing rate, has better adaptability to other concrete materials of cement ground materials, is easier to start slurry, improves the comprehensive performance of the water reducer, and meets the on-site concrete adaptation requirement.

And step S40, dropwise adding the solution A and the solution B into the mixed solution, and stirring and reacting at normal temperature to obtain the water reducer.

In the embodiment, the liquid A and the liquid B are simultaneously dripped into the mixed liquid, namely the liquid A and the liquid B are synchronously dripped, so that the dripping time can be greatly shortened, the synthesis time is greatly reduced, and the production efficiency is improved.

Further, the dropping time of the liquid A and the liquid B is not more than 1h, namely the liquid A and the liquid B can be completely dropped within one hour, so that the dropping time is greatly shortened. In addition, the reaction time is 0.8-1.5 h, so that the full copolymerization reaction is ensured, and the solid content is ensured to be about 50%. Wherein the solid content refers to the percentage of the water reducing agent product (dry product) relative to the total amount of the raw material components.

In addition, the invention also provides concrete, which comprises a water reducing agent, wherein the water reducing agent comprises the following raw material components: isopentene polyoxyethylene ether, acrylic acid, hydrogen peroxide, ascorbic acid, sodium hypophosphite, anhydrous sodium sulfite and oxalic acid; the weight ratio of the isopentenyl polyoxyethylene ether to the acrylic acid to the hydrogen peroxide to the ascorbic acid to the sodium hypophosphite to the anhydrous sodium sulfite to the oxalic acid is 360: 25.2-36: 2-4: 1-4: 3-5: 1-3. The concrete adopts all the technical schemes of all the embodiments, so that the concrete at least has all the beneficial effects brought by the technical schemes of the embodiments, and the details are not repeated.

The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.

Example 1

The formula of the water reducing agent comprises the following raw materials: 360 parts of isopentene polyoxyethylene ether, 25.2 parts of acrylic acid, 4 parts of hydrogen peroxide, 3 parts of ascorbic acid, 4 parts of sodium hypophosphite, 1 part of anhydrous sodium sulfite and 1.5 parts of oxalic acid

The preparation method comprises the following steps: the raw material components are weighed according to the formula. And dissolving acrylic acid in water to obtain solution A. Adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B. Stirring the water solution of the isopentenyl polyoxyethylene ether for 20min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 10min to obtain a mixed solution. And finally, simultaneously dripping the solution A and the solution B into the mixed solution, controlling the dripping time to be not more than 1h, after finishing dripping, continuously stirring at normal temperature to react for 1h, and discharging to obtain the water reducer.

Example 2

The formula of the water reducing agent comprises the following raw materials: 360 parts of isopentene polyoxyethylene ether, 26.5 parts of acrylic acid, 2.5 parts of hydrogen peroxide, 2 parts of ascorbic acid, 4.6 parts of sodium hypophosphite, 1.3 parts of anhydrous sodium sulfite and 2.5 parts of oxalic acid.

The preparation method comprises the following steps: the raw material components are weighed according to the formula. And dissolving acrylic acid in water to obtain solution A. Adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B. Stirring the water solution of the isopentenyl polyoxyethylene ether for 20min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 10min to obtain a mixed solution. And finally, simultaneously dripping the solution A and the solution B into the mixed solution, controlling the dripping time to be not more than 1h, after finishing dripping, continuously stirring at normal temperature to react for 1h, and discharging to obtain the water reducer.

Example 3

The formula of the water reducing agent comprises the following raw materials: 360 parts of isopentene polyoxyethylene ether, 36 parts of acrylic acid, 3 parts of hydrogen peroxide, 1 part of ascorbic acid, 3 parts of sodium hypophosphite, 1.5 parts of anhydrous sodium sulfite and 1 part of oxalic acid

The preparation method comprises the following steps: the raw material components are weighed according to the formula. And dissolving acrylic acid in water to obtain solution A. Adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B. Stirring the water solution of the isopentenyl polyoxyethylene ether for 25min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 12min to obtain a mixed solution. And finally, simultaneously dripping the solution A and the solution B into the mixed solution, controlling the dripping time to be not more than 1h, after finishing dripping, continuously stirring at normal temperature to react for 1h, and discharging to obtain the water reducer.

Example 4

The formula of the water reducing agent comprises the following raw materials: 360 parts of isopentene polyoxyethylene ether, 30 parts of acrylic acid, 2 parts of hydrogen peroxide, 4 parts of ascorbic acid, 5 parts of sodium hypophosphite, 3 parts of anhydrous sodium sulfite and 3 parts of oxalic acid

The preparation method comprises the following steps: the raw material components are weighed according to the formula. And dissolving acrylic acid in water to obtain solution A. Adding ascorbic acid and anhydrous sodium sulfite into water to obtain solution B. Stirring the water solution of the isopentenyl polyoxyethylene ether for 15min, then sequentially adding oxalic acid, sodium hypophosphite and hydrogen peroxide, and stirring for 8min to obtain a mixed solution. And finally, simultaneously dripping the solution A and the solution B into the mixed solution, controlling the dripping time to be not more than 1h, after finishing dripping, continuously stirring at normal temperature to react for 1h, and discharging to obtain the water reducer.

Comparative example 1

The formula of the water reducing agent comprises the following raw materials: 4000 parts of isopentene polyoxyethylene ether, 300 parts of acrylic acid, 12 parts of mercaptopropionic acid, 25 parts of hydrogen peroxide and 6 parts of vitamin C

The preparation method comprises the following steps: the raw material components are weighed according to the formula. Dissolving hydrogen peroxide in water to prepare solution A; dissolving vitamin C and mercaptopropionic acid in water to obtain solution B; and dissolving acrylic acid in water to obtain solution C. Introducing steam into a reaction kettle filled with isopentenyl polyoxyethylene ether, heating to 53 ℃, dropwise adding the solution A (dropwise adding is finished within 140 min), dropwise adding the solution B (dropwise adding is finished within 140 min) after 10min, and dropwise adding the solution C (dropwise adding is finished within 120 min) after 10 min. Controlling the reaction temperature at 53 ℃, and stirring to react to obtain the water reducing agent.

The water reducing agents prepared in examples 1 to 4 and comparative example 1 were subjected to performance examination, and items of examination included specific gravity, pH, initial value of net cement paste fluidity, and net cement paste fluidity after 1h of plastic retention. The results are shown in Table 3.

TABLE 3 examination of the combination Properties of the Water-reducing Agents

The water reducing agents obtained in examples 1 to 4 and comparative example 1 were used to prepare the following concretes.

C50 concrete

The formula is as follows: 150 parts of water, 320 parts of cement, 670 parts of sand, 1050 parts of stones, 100 parts of fly ash, 100 parts of mineral powder, 30 parts of water reducing agent and 7.5 parts of slump retaining agent, wherein the water-cement ratio is 0.29, and the sand rate is 39%.

(II) C30 concrete

The formula is as follows: 165 parts of water, 230 parts of cement, 780 parts of sand, 1070 parts of stones, 70 parts of fly ash, 50 parts of mineral powder, 33 parts of water reducing agent and 8.25 parts of slump retaining agent, wherein the water-cement ratio is 0.47, and the sand rate is 42%.

The combination of the properties of the C50 concrete and the C30 concrete were examined and the results are shown in Table 4 below. Wherein, T0: initial slump; l0: an initial expansion degree; t2: slump after 2 hours; l2: the degree of spreading after 2 hours.

TABLE 4 combination of properties of the concretes

Compared with a comparative example, the water reducing agent prepared in each example has the advantages of equivalent water reducing rate and volume weight, good overall workability, better hand feeling, better slump loss within 2 hours, better comprehensive performance of the compounded concrete and better slump retentivity.

The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.