CN117800637B

CN117800637B - Polycarboxylic acid pumping aid and preparation process thereof

Info

Publication number: CN117800637B
Application number: CN202311851081.1A
Authority: CN
Inventors: 计伟勇; 徐琪勇; 陈晓波; 叶刚; 沈继平
Original assignee: Zhejiang Wulong Chemical Industrial Stock Co ltd
Current assignee: Zhejiang Wulong Chemical Industrial Stock Co ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-07-02
Anticipated expiration: 2043-12-29
Also published as: CN117800637A

Abstract

The invention provides a polycarboxylic acid pumping agent and a preparation process thereof, and relates to the technical field of concrete additive processing. The polycarboxylic acid pumping aid is mainly prepared by mixing a polycarboxylic acid water reducer with the solid content of 40%, sodium lignin sulfonate, sodium methacrylate sulfonate, sodium dodecyl sulfate, a plant fiber combined starch modified material and sodium gluconate, wherein the plant fiber combined starch modified material is obtained by mixing plant fiber powder with starch, gelatinizing, steam explosion treatment and finally oxidizing modification. The invention overcomes the defects of the prior art, effectively ensures that the concrete has higher fluidity and slump in a longer time, improves the early strength of the subsequent concrete, and comprehensively improves the construction stability of the concrete.

Description

Polycarboxylic acid pumping aid and preparation process thereof

Technical Field

The invention relates to the technical field of concrete additive processing, in particular to a polycarboxylic acid pumping agent and a preparation process thereof.

Background

The concrete admixture is taken as a fifth component of concrete and is a necessary means for improving and improving the performance of modern concrete. The polycarboxylate water reducer (PCA) is used as a concrete admixture of the most mainstream variety at present, and has the characteristics of high water reducing rate, excellent slump retaining performance, rapid strength increase, extremely low alkali content, environmental protection and the like, meets the requirements of the development of the modern concrete technology towards high strength, green and high performance, and becomes a hot spot for research and development of the concrete admixture at home and abroad.

The concrete is transported to a construction site from a mixing station in the current stage, but the concrete is partially coagulated and caked due to low use efficiency in the transportation time process or the construction, so that the pumping agent is required to be added when the concrete is mixed, the pumping performance of the concrete can be well improved, the caked of the concrete in the transportation or the waiting construction process is effectively prevented, and the slump retaining performance of the concrete is comprehensively improved.

The conventional pumping aid is composed of a water reducing agent mixed retarder, and the conventional pumping aid can achieve the purpose of slump retention and retarding to a certain extent, but most of the conventional pumping aid can enable concrete to retain more than 80% of slump within 1h, so that the fluidity and slump retention effect of concrete after 2h are poor, and the stability of the concrete is lowered for large-scale construction and long-range concrete transportation, so that the slump retention performance of the concrete can be improved, the fluidity of the concrete can be effectively improved, and the loss and waste are reduced by optimally designing a novel polycarboxylic pumping aid.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the polycarboxylic acid pumping agent and the preparation process thereof, which effectively ensure that the concrete has higher fluidity and slump in a longer time, improve the early strength of the subsequent concrete and comprehensively improve the construction stability of the concrete.

In order to achieve the above object, the technical scheme of the present invention is realized by the following technical scheme:

The polycarboxylic acid pumping agent is prepared from the following raw materials in percentage by mass: 10-40% of polycarboxylic acid water reducer with solid content of 40%, 2-4% of sodium lignin sulfonate, 2-4% of sodium methacrylate sulfonate, 1-1.5% of sodium dodecyl sulfate, 3-7% of plant fiber combined starch modified material, 2-4% of sodium gluconate and the balance of water; wherein the plant fiber and starch combined modified material is obtained by mixing plant fiber powder with the grain diameter of 100-400 mu m and starch with the mass ratio of 1:1-2, gelatinizing, performing steam explosion treatment, and performing post-oxidation modification.

Preferably, the solid content of the polycarboxylic acid water reducer with the solid content of 40% comprises the following raw materials in parts by mass: 320-380 parts of isobutenyl polyethylene glycol ether, 20-30 parts of acrylic acid, 8-12 parts of methacrylic acid polyethylene glycol ester, 2-5 parts of L-ascorbic acid, 1-2 parts of thioglycollic acid, 1-4 parts of butyl acrylate and 3-5 parts of hydrogen peroxide.

Preferably, the preparation method of the polycarboxylic acid water reducer with the solid content of 40 percent comprises the following steps:

S1-1, mixing acrylic acid, polyethylene glycol methacrylate and butyl acrylate, adding 10 times of water, and uniformly stirring to obtain a mixed solution A for later use;

S1-2, mixing L-ascorbic acid and thioglycollic acid, adding 40 times of water, and uniformly mixing and stirring to obtain a mixed solution B for later use;

s1-3, adding water into the isobutylene-based polyethylene glycol ether, stirring and dissolving, adding hydrogen peroxide, and uniformly mixing and stirring to obtain a mixed solution C for later use;

S1-4, carrying out water bath heat preservation on the mixed solution C at 60-65 ℃, then slowly dropwise adding the mixed solution A and the mixed solution B into the dissolving solution, carrying out heat preservation for 1-2h after dropwise adding, then regulating the pH value to be neutral, and then supplementing water to regulate the solid content to be 40%.

Preferably, the dripping time of the mixed solution A in the step S1-4 is 2-3h, and the dripping time of the mixed solution B is 3-5h.

Preferably, the preparation method of the plant fiber combined starch modified material comprises the following steps:

S2-1, mixing plant fiber powder and starch, adding 2 times of water, uniformly stirring, heating to 60-70 ℃, and carrying out heat preservation and stirring treatment for 30-60min to obtain a mixture for later use;

s2-2, performing steam explosion treatment on the mixture to obtain a steam exploded material for later use;

s2-3, adding 2 times of clear water into the steam explosion material, uniformly mixing and stirring, adding an oxidant, stirring and mixing for reaction for 1-1.5h, and then carrying out suction filtration and drying to obtain the plant fiber combined starch modified material.

Preferably, the pressure of the steam explosion treatment in the step S2-2 is 2Mpa, the treatment temperature is 121 ℃, and the treatment time is 50-60S.

Preferably, the oxidant in the step S-3 is hydrogen peroxide, and the addition amount of the oxidant is 15-30% of the mass of the starch raw material.

Preferably, the polycarboxylic acid pumping agent is added in an amount of 0.8-1.5% of the total mass of the gel material in the concrete when in use.

The preparation method of the polycarboxylic acid pumping agent comprises the following steps:

(1) Mixing sodium lignin sulfonate, sodium methacrylate sulfonate and dodecyl sulfuric acid, adding water, stirring and mixing uniformly to obtain a primary mixed solution for later use;

(2) Uniformly mixing and stirring the polycarboxylic acid water reducer with the solid content of 40% and the primary mixed solution to obtain a mixture A for standby;

(3) Adding water into the plant fiber and starch modified material, uniformly mixing and stirring, adding sodium gluconate, and continuously uniformly stirring to obtain a mixture B for later use;

(4) Under the water bath condition, adding the mixture A into the rest water, uniformly stirring, then slowly adding the mixture B, and stirring while adding to obtain the polycarboxylic pumping aid.

Preferably, the water bath temperature in the step (4) is 50-60 ℃, and the time for adding the mixture B is 15-30min.

The invention provides a polycarboxylic pumping aid and a preparation process thereof, which have the advantages that compared with the prior art:

According to the invention, the polycarboxylate water reducer is taken as a mother solution, sodium lignosulfonate, sodium methallyl sulfonate and sodium dodecyl sulfate are added in a supplementing manner, so that the concrete retarding effect is effectively improved, the water reducing property of the pumping agent on the concrete is further improved through the addition of the plant fiber and starch modified material, meanwhile, the strength of the concrete is further improved while the good slump retaining property is ensured, wherein the water reducing effect on the concrete can be effectively improved through the steam explosion treatment reoxidation after the starch is semi-gelatinized, the starch and plant fiber are jointly modified, the influence of starch on the concrete fluidity is effectively reduced while the water reducing effect is enhanced, so that the slump of the pumping agent in the concrete is ensured to be more than 92% when the adding amount of the pumping agent in the concrete is 0.8-1.5% (calculated by gel component), and the subsequent strength of the concrete is effectively improved.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1:

1. the polycarboxylic acid water reducer with the solid content of 40 percent is prepared by the following steps:

(1) Preparing materials: 350 parts of isobutenyl polyethylene glycol ether, 25 parts of acrylic acid, 10 parts of polyethylene glycol methacrylate, 3.5 parts of L-ascorbic acid, 1.5 parts of thioglycollic acid, 3 parts of butyl acrylate and 4 parts of hydrogen peroxide;

(2) Mixing acrylic acid, polyethylene glycol methacrylate and butyl acrylate, adding 10 times of water, and uniformly stirring to obtain a mixed solution A for later use;

(3) Mixing L-ascorbic acid and thioglycollic acid, adding 40 times of water, mixing and stirring uniformly to obtain a mixed solution B for standby;

(4) Adding water into the isobutylene-based polyethylene glycol ether, stirring and dissolving, adding hydrogen peroxide, and uniformly mixing and stirring to obtain a mixed solution C for standby;

(5) And (3) carrying out water bath heat preservation on the mixed solution C at 60 ℃, then slowly dropwise adding the mixed solution A and the mixed solution B into the solution, wherein the total dropwise adding time of the mixed solution A is 2.5h, the total dropwise adding time of the mixed solution B is 4h, and after dropwise adding is completed, carrying out heat preservation for 1.5h, standing for reaction, then adopting 30% sodium hydroxide solution to adjust the pH value to be neutral, and then supplementing water to adjust the solid content to 40%, thereby obtaining the polycarboxylic acid water reducer with the solid content of 40%.

2. Preparation of modified materials:

(1) Preparation of modified material A:

s1, preparing materials: selecting coconut fiber powder with the particle size of 100-400 mu m and common corn starch, and mixing according to the mass ratio of 1:1 to obtain premix for later use;

S2, adding 2 times of water into the premix, uniformly stirring, heating to 65 ℃, and carrying out heat preservation and stirring treatment for 45min to obtain a mixture for later use;

s3, subjecting the mixture to steam explosion treatment at a high temperature of 121 ℃ for 55 seconds under the pressure of 2Mpa to obtain a steam exploded material for later use;

S4, adding 2 times of clear water into the steam explosion material, uniformly mixing and stirring, adding hydrogen peroxide accounting for 25% of the mass of the common corn starch, stirring and mixing for reaction for 1.2 hours, carrying out suction filtration, and drying at the temperature of 40 ℃ until the water content is less than or equal to 8%, thus obtaining the modified material A.

(2) Preparation of modified material B:

S2, adding 2 times of clear water into the premix, uniformly mixing and stirring, adding hydrogen peroxide accounting for 25% of the mass of the common corn starch, stirring and mixing for 1.2 hours, carrying out suction filtration, and drying at the temperature of 40 ℃ until the water content is less than or equal to 8%, thus obtaining the modified material B.

(3) Preparation of modified material C:

s1, preparing materials: selecting coconut fiber powder with the particle size of 100-400 mu m as a raw material;

s2, adding water with the volume being 2 times of that of the raw materials, uniformly stirring, heating to 65 ℃, and carrying out heat preservation and stirring treatment for 45min to obtain premix for later use;

s3, performing steam explosion treatment on the premix at a high temperature of 121 ℃ for 55 seconds under the pressure of 2Mpa to obtain a steam exploded material for later use;

S4, adding 2 times of clear water into the steam explosion material, uniformly mixing and stirring, adding 25% of hydrogen peroxide by mass of the raw material, stirring and mixing for reaction for 1.2 hours, carrying out suction filtration, and drying at the temperature of 40 ℃ until the water content is less than or equal to 8%, thus obtaining the modified material C.

(4) Preparation of modified material D:

S4, adding 2 times of clear water into the steam explosion material, uniformly mixing and stirring, adding hydrogen peroxide accounting for 25% of the mass of the raw material, stirring and mixing for reaction for 1.2 hours, carrying out suction filtration, and drying at the temperature of 40 ℃ until the water content is less than or equal to 8%, thus obtaining the modified material D.

Example 2:

preparation of a pumping agent:

(1) Preparing materials: the preparation method comprises the following steps of: 25% of polycarboxylic acid water reducer with solid content of 40%, 3% of sodium lignin sulfonate, 3% of sodium methacrylate sulfonate, 1.2% of sodium dodecyl sulfate, 5% of modified material, 3% of sodium gluconate and the balance of water;

(2) Mixing sodium lignin sulfonate, sodium methacrylate sulfonate and sodium dodecyl sulfate, adding water, stirring and mixing uniformly to obtain a primary mixed solution for later use;

(3) The polycarboxylic acid water reducer with the solid content of 40 percent and the primary mixed liquid are mixed and stirred uniformly to obtain a mixture A for standby

(4) Adding water into the modified material, uniformly mixing and stirring, then adding sodium gluconate, and continuously uniformly stirring to obtain a mixture B for later use;

(5) And (3) adding the mixture A into the rest water under the water bath condition of 55 ℃, uniformly stirring, slowly adding the mixture B for 20min, and stirring while adding to obtain the polycarboxylic acid pumping agent.

The polycarboxylic acid water reducer with the solid content of 40% prepared in the above example 1 is adopted as a raw material, the different modified materials in the above example 1 and the sodium lignin sulfonate, sodium methacrylate and sodium dodecyl sulfate which are selectively added are respectively selected, and the other materials are the same, and the pumping agent of the experimental groups 1-6 is obtained by processing according to the preparation method of the pumping agent, and the pumping agent modified materials of the experimental groups 1-6 are selected as shown in the following table 1:

TABLE 1

And (3) detection:

the performance of the pumping agents prepared in the above experimental groups 1-6 was examined:

experimental raw material selection:

and (3) cement: conch P.O42.5 cement is;

fine aggregate: middle sand with fineness modulus of 2.7;

Coarse aggregate: continuous graded broken stone with the grain diameter of 5 mm-20 mm;

The amount of the pumping agent added was set to 1.0% (calculated as gel material), and the following concrete in the proportion of table 2 was designed:

TABLE 2

The concrete properties of the above C-0, C-1, C-2, C-3, C-4, C-5, C-6 were tested according to GB 8076-2008, and the specific results are shown in tables 3 and 4 below:

TABLE 3 Table 3

TABLE 4 Table 4

From the test results shown in tables 3 and 4, the addition of the pumping agent prepared in experiment group 1 can effectively improve the slump retaining effect of the concrete and further improve the early strength of the concrete.

The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The polycarboxylic acid pumping agent is characterized by being prepared from the following raw materials in percentage by mass: 10-40% of polycarboxylic acid water reducer with solid content of 40%, 2-4% of sodium lignin sulfonate, 2-4% of sodium methacrylate sulfonate, 1-1.5% of sodium dodecyl sulfate, 3-7% of plant fiber combined starch modified material, 2-4% of sodium gluconate and the balance of water;

The plant fiber combined starch modified material is obtained by mixing plant fiber powder with the grain diameter of 100-400 mu m and starch with the mass ratio of 1:1-2, gelatinizing, then performing steam explosion treatment, and performing post-oxidation modification, and the specific preparation method of the plant fiber combined starch modified material comprises the following steps:

2. The polycarboxylic acid pumping aid according to claim 1, wherein the solid content of the polycarboxylic acid water reducer with the solid content of 40% comprises the following raw materials in parts by mass: 320-380 parts of isobutenyl polyethylene glycol ether, 20-30 parts of acrylic acid, 8-12 parts of methacrylic acid polyethylene glycol ester, 2-5 parts of L-ascorbic acid, 1-2 parts of thioglycollic acid, 1-4 parts of butyl acrylate and 3-5 parts of hydrogen peroxide.

3. The polycarboxylic acid-based pumping aid according to claim 2, wherein the preparation method of the polycarboxylic acid-based water reducing agent with the solid content of 40% comprises the following steps:

4. A polycarboxylic acid-based pumping agent according to claim 3, characterized in that: and in the step S1-4, the dropwise adding time of the mixed solution A is 2-3h, and the dropwise adding time of the mixed solution B is 3-5h.

5. A polycarboxylic acid-based pumping agent according to claim 1, characterized in that: the pressure of the steam explosion treatment in the step S2-2 is 2Mpa, the treatment temperature is 121 ℃, and the treatment time is 50-60S.

6. A polycarboxylic acid-based pumping agent according to claim 1, characterized in that: the oxidant in the step S2-3 is hydrogen peroxide, and the addition amount of the oxidant is 15-30% of the mass of the starch raw material.

7. A polycarboxylic acid-based pumping agent according to claim 1, characterized in that: the addition amount of the polycarboxylic acid pumping agent is 0.8-1.5% of the total mass of the gel material in the concrete when the polycarboxylic acid pumping agent is used.

8. A process for the preparation of the polycarboxylic acid-based pumping aid according to any of claims 1 to 7, comprising the steps of:

9. The method for producing a polycarboxylic acid-based pumping agent according to claim 8, characterized in that: the water bath temperature in the step (4) is 50-60 ℃, and the adding time of the mixture B is 15-30min.