CN112408896B

CN112408896B - Super-retarding concrete and preparation method thereof

Info

Publication number: CN112408896B
Application number: CN202011315654.5A
Authority: CN
Inventors: 李海斌; 熊还超; 张朋; 詹赡; 陈亮
Original assignee: Hubei Yunhai Concrete Co ltd
Current assignee: Hubei Yunhai Concrete Co ltd
Priority date: 2020-11-21
Filing date: 2020-11-21
Publication date: 2022-05-13
Anticipated expiration: 2040-11-21
Also published as: CN112408896A

Abstract

The invention relates to super-retarding concrete and a preparation method thereof, and relates to the technical field of concrete preparation. The paint comprises the following components in parts by weight: 340-360 parts of a gel material, 700-900 parts of artificial sand, 900-1200 parts of broken stone, 7-8 parts of a water reducing agent, 8-10 parts of a retarder and 150-190 parts of water; the gel material is formed by mixing cement, mineral powder and coal ash, the weight of the mineral powder and the coal ash in the gel material accounts for not less than 10% of the weight of the gel material, the sum of the total weight of the mineral powder and the coal ash in the gel material accounts for 20-50% of the weight of the gel material, and the retarder is formed by mixing sodium citrate, sodium gluconate, phosphogypsum, coal ash and carbide slag according to the ratio of (20-24): (16-18): (35-42): (16-20): 3 in a weight ratio. The invention can control the concrete not to be initially set within 48h, and is convenient to transport.

Description

Super-retarding concrete and preparation method thereof

Technical Field

The invention relates to the technical field of concrete preparation, in particular to super-retarding concrete and a preparation method thereof.

Background

Along with the development of society and the needs of various large-scale projects, the application range of concrete is continuously expanded, the performance requirements on the concrete are higher and higher, and in many large-scale projects, in order to meet the requirements of construction procedures and construction duration, the setting time of the concrete is required to be prolonged, and the strength in the later stage of setting is required to be ensured.

Now, a Chinese patent with a publication number of CN107586077B is searched, and discloses an ultra-retarding concrete, which comprises the following components in parts by weight: 175 parts of water 165-containing material, 260 parts of cement 160-containing material, 56-64 parts of mineral powder, 80-160 parts of fly ash, 841 parts of sand 835-containing material, 983 parts of stones and 6-8.5 parts of admixture; the admixture comprises the following components in parts by weight: 10-14 parts of retarder and 35-41 parts of water reducer; the water reducing agent comprises the following components in parts by weight: 7-9 parts of polyether slump-retaining water reducer, 9-11 parts of polyether water-retaining water reducer and 19-21 parts of methyl allyl alcohol polyoxyethylene ether; the polyether slump-retaining water reducer comprises prenyl polyoxyethylene ether and hydroxyethyl acrylate; the polyether water-retaining water reducing agent is butanediol monoethylene ether polyoxyethylene ether.

Although the ultra-retarding concrete has good retarding performance, the retarder of the ultra-retarding concrete mainly uses sodium gluconate and sodium citrate which are expensive, so the cost is relatively high.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the ultra-retarding concrete and the preparation method thereof, and the ultra-retarding concrete has the advantages of low cost, capability of meeting the technical requirements of C30 concrete, capability of controlling the concrete not to be subjected to initial setting within 48h, thereby prolonging the setting time of the concrete and convenience in transportation.

In a first aspect, the above object of the present invention is achieved by the following technical solutions:

the super-retarding concrete comprises the following components in parts by weight: 340-360 parts of a gel material, 700-900 parts of artificial sand, 900-1200 parts of broken stone, 7-8 parts of a water reducing agent, 8-10 parts of a retarder and 150-190 parts of water; the gel material is formed by mixing cement, mineral powder and coal ash, the weight of the mineral powder and the coal ash in the gel material accounts for not less than 10% of the weight of the gel material, the sum of the total weight of the mineral powder and the coal ash in the gel material accounts for 20-50% of the weight of the gel material, and the retarder is formed by mixing sodium citrate, sodium gluconate, phosphogypsum, coal ash and carbide slag according to the ratio of (20-24): (16-18): (35-42): (16-20): 3 in a weight ratio.

By adopting the technical scheme, mineral powder and coal ash with lower cost are used in the gel material as much as possible, and the retarder enables the surface of concrete particles to be coated with a layer of membrane water, so that the fluidity of the concrete is enhanced, and the initial setting time and the final setting time of the concrete are further prolonged; the water reducing agent can reduce the using amount of water in the recycled concrete, is favorable for accelerating the solidification of the recycled concrete and reduces the condition that the strength of the recycled concrete is reduced due to the fact that impurities enter the recycled concrete in the solidification process, so that under the combined action of water, a gel material, the water reducing agent and the retarder, the concrete solidifying agent is low in cost, can meet the technical requirements of C30 concrete, and can control the concrete not to be initially solidified within 48 hours, so that the solidification time of the concrete is prolonged, and the concrete is convenient to transport.

The retarder can be further configured in a preferred example, the weight ratio of the sodium citrate to the sodium gluconate to the phosphogypsum to the fly ash to the carbide slag is 22:18:39:18: 3.

By adopting the technical scheme, the invention discloses a preparation scheme of the retarder, under the action of sodium citrate and sodium gluconate, the retarder can wrap a layer of water film on the surface of concrete particles, so that the fluidity of concrete is improved, the initial setting time and the final setting time of the retarder are greatly prolonged, the cost of the retarder is reduced to a certain extent under the action of auxiliary ingredients of phosphogypsum, fly ash and carbide slag, and meanwhile, after the ingredients of phosphogypsum, fly ash and carbide slag are added, the strength of the water film formed by the sodium citrate and sodium gluconate is reduced to a certain extent, but the requirement of controlling the concrete not to be initially set within 48h and meeting the transportation requirement in the aspect can be met. Meanwhile, the formula is the optimal preparation scheme of the retarder, and the retarder can be adopted to control the concrete not to be subjected to initial setting within 52 hours under the condition of reducing the cost as much as possible, so that the transportation requirement is met.

The invention can be further configured in a preferred example to comprise the following components in parts by weight: 210 parts of cement, 70 parts of mineral powder, 70 parts of coal ash, 800 parts of artificial sand, 1050 parts of broken stone, 7.7 parts of a water reducing agent, 9.0 parts of a retarder and 165 parts of water.

By adopting the technical scheme, the invention can meet the technical requirements of C20 concrete and can ensure that the initial setting time of the concrete is 54.8 hours and the final setting time is 63.7 hours under the condition of reducing the cost of raw materials as much as possible.

The invention can be further configured in a preferred example, the crushed stone of the crushed stone continuous grading has the diameter of 5-15 mm.

Through adopting above-mentioned technical scheme, adopt the rubble of above-mentioned particle diameter can let can satisfy the technical requirement of C30 concrete, and does not influence the delayed coagulation effect of retarder.

The invention in a preferred embodiment may be further configured such that the sodium citrate and the sodium gluconate are both analytically pure.

By adopting the technical scheme, the invention discloses the use requirements of sodium citrate and sodium gluconate, therefore, other ingredients are required to be added into the coagulant, and the purity of the sodium citrate and the sodium gluconate is required to be ensured.

In a preferred example of the present invention, the water reducing agent is a polyhydroxy water reducing agent, and the water reducing rate is 25 to 35%.

By adopting the technical scheme, the water reducing agent has ultrahigh water reducing rate and water retention performance, so that fresh concrete has good cohesiveness and wrapping property, is not easy to segregate and bleed, and has excellent concrete fluidity, good homogeneity and workability, and the slump loss resistance of the water reducing agent is good, so that the concrete has high strength and better durability.

In a better example, the invention can be further configured that the phosphogypsum is solid waste residue generated when phosphorite is treated by sulfuric acid in phosphoric acid production, the water content is 22-25%, and the particle size is less than or equal to 0.2 mm.

By adopting the technical scheme, the phosphogypsum is relatively low in cost, can be used as a retarder, has small influence on the performance of the retarder after being added into a mixture of sodium citrate and sodium gluconate as an auxiliary retarder, but greatly reduces the cost.

In a preferred example, the carbide slag is waste slag which is obtained by hydrolyzing carbide to obtain acetylene gas and takes calcium hydroxide as a main component, the solid content is more than or equal to 60%, the water content is 35-40%, and the particle size is less than or equal to 0.2 mm.

By adopting the technical scheme, the carbide slag not only can adjust the pH value of the concrete, but also can provide Ca to the concrete²⁺And Ca (O)H）₂ ，Ca²⁺And Ca (OH)₂Can play a certain role in dehydration.

In a second aspect, the above object of the present invention is achieved by the following technical solutions:

the preparation method of the super-retarding concrete comprises the following steps:

s1: putting cement, mineral powder, coal ash, artificial sand, a water reducing agent, a retarder and water into a concrete mixer for stirring to obtain a primary mixed material;

s2: putting the crushed stone particles into the primary mixed material obtained in the step S1, and stirring to obtain super-retarding concrete;

wherein the primary mixed material is prepared by the following steps:

s11: the cement, the mineral powder, the coal ash and the artificial sand are dry-mixed in a concrete mixer, and the mixture is uniformly mixed to obtain a primary mixed dry material;

s12: and (4) adding 70% of the required water into the primary mixed dry material obtained in the step (S11) and uniformly stirring, adding the water reducing agent, the retarder and the residual 30% of water without stopping the concrete mixer after stirring, and continuously stirring after the addition is finished to form the primary mixed material after the primary mixed dry material is uniformly stirred.

According to the invention, mineral powder and coal ash with lower cost are used in the gel material as much as possible, and the retarder enables the surface of concrete particles to be coated with a layer of membrane water, so that the fluidity of the concrete is enhanced, and the initial setting time and the final setting time of the concrete are further prolonged; the water reducing agent can reduce the using amount of water in the recycled concrete, is beneficial to accelerating the solidification of the recycled concrete, and reduces the condition that the strength of the recycled concrete is reduced due to impurities entering the concrete in the solidification process; therefore, under the combined action of water, a gel material, a water reducing agent and a retarder, the concrete disclosed by the invention is low in cost, can meet the technical requirements of C30 concrete, and can control the concrete not to be subjected to initial setting within 48 hours, so that the setting time of the concrete disclosed by the application is prolonged, and the transportation is convenient.

The invention may further be configured in a preferred example such that the retarder is prepared by: firstly mixing sodium citrate and sodium gluconate at normal temperature, then standing the mixed solution of the sodium citrate and the sodium gluconate for at least 3 minutes, sequentially adding phosphogypsum, then stirring and fully stirring the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, then sequentially adding fly ash and carbide slag into the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, and finally putting the retarder with the fly ash and the carbide slag into a storage box for storage for later use.

By adopting the technical scheme, the sodium citrate and the sodium gluconate are fully mixed, then the phosphogypsum is added for stirring, and finally the fly ash and the carbide slag are added for stirring, so that the components of the retarder can be mixed more uniformly, and the retarding effect on concrete is better.

In summary, the invention includes at least one of the following beneficial technical effects:

1. the retarder enables the surface of concrete particles to be coated with a layer of membrane water, so that the fluidity of the concrete is enhanced, and the initial setting time and the final setting time of the concrete are further prolonged; the water reducing agent can reduce the using amount of water in the recycled concrete, is favorable for accelerating the solidification of the recycled concrete and reduces the condition that the strength of the recycled concrete is reduced due to the fact that impurities enter the recycled concrete in the solidification process, so that under the combined action of water, a gel material, the water reducing agent and the retarder, the concrete solidifying agent is low in cost, can meet the technical requirements of C30 concrete, and can control the concrete not to be initially solidified within 48 hours, so that the solidification time of the concrete is prolonged, and the concrete is convenient to transport.

2. Under the action of sodium citrate and sodium gluconate, the retarder can wrap a layer of water film on the surface of concrete particles, so that the fluidity of the concrete is improved, the initial setting time and the final setting time of the retarder are greatly prolonged, the cost of the retarder is reduced to a certain extent under the action of auxiliary ingredients, namely phosphogypsum, fly ash and carbide slag, and meanwhile, after the ingredients, namely phosphogypsum, fly ash and carbide slag, the strength of the water film formed by the sodium citrate and the sodium gluconate is reduced to a certain extent, but the requirement of controlling the concrete not to be initially set within 48 hours and meeting the transportation requirement of the invention can be met.

3. The invention uses mineral powder and coal ash with lower cost in the gel material as much as possible, thereby reducing the cost of raw materials as much as possible under the condition of ensuring that the invention can meet the technical requirements of C30 concrete.

Drawings

FIG. 1 is a schematic flow chart of a preparation method of the ultra-retarding concrete of the invention;

FIG. 2 is a schematic flow diagram of the present invention for obtaining a primary mix.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The invention mainly aims to provide super-retarding concrete, all related products are sold in the market, and the concrete is as follows: PO42.5 cement is selected as cement, and fly ash is selected as fly ash

The method comprises the following steps of selecting S95-grade mineral powder as mineral powder, selecting artificial sand with fineness of 2.8 as artificial sand, selecting a polyhydroxy water reducing agent as a water reducing agent, wherein the water reducing rate is 25%, selecting solid waste residues generated when phosphorite is treated by sulfuric acid in phosphoric acid production as phosphogypsum, the water content is 22% -25%, the particle size is less than or equal to 0.2mm, obtaining waste residues with calcium hydroxide as a main component after acetylene gas is obtained by calcium carbide hydrolysis, the solid content is greater than or equal to 60%, the water content is 35% -40%, the particle size is less than or equal to 0.2mm, and analyzing and purifying sodium citrate and sodium gluconate.

Preparation example 1

The preparation example provides a retarder for concrete, which can control the concrete not to be subjected to initial setting within 48 hours, thereby prolonging the setting time of the concrete and facilitating the transportation; specifically, the retarder is prepared by compounding sodium citrate, sodium gluconate, phosphogypsum, fly ash and carbide slag according to a certain weight ratio, and the specific weight fractions of the components of the retarder are detailed in table 1 (1 part by weight =1 kg).

In this example, the retarder was prepared as follows:

firstly, mixing sodium citrate and sodium gluconate at normal temperature (such as 20-40 ℃, preferably 30 ℃), then standing the mixed solution of the sodium citrate and the sodium gluconate for at least 3 minutes, sequentially adding phosphogypsum, then stirring and fully stirring the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, then sequentially adding fly ash and carbide slag into the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, and finally placing a retarder with the fly ash and the carbide slag into a storage box for storage for later use.

Preparation examples 2 to 6

Compared with the preparation example 1, the retarder is different in the components of sodium citrate, sodium gluconate, phosphogypsum, fly ash and carbide slag, and the detailed weight ratio numerical values of the components of the retarder are shown in the table 1 (1 part by weight =1 kg).

TABLE 1

Example 1

The embodiment discloses super-retarding concrete which comprises a gel material, artificial sand, broken stone, a water reducing agent, a retarder and water, wherein the gel material is formed by mixing cement, mineral powder and coal ash, the weight of the mineral powder and the coal ash in the gel material is not less than 10% of the weight of the gel material, the sum of the total weight of the mineral powder and the coal ash in the gel material is 20-50% of the weight of the gel material, the retarder is selected from the retarder recorded in preparation example 1, and the concrete weight parts (1 weight part =1 kg) of the concrete are shown in table 2 in detail; .

At this time, the method for preparing the concrete of this example includes the steps of:

s2: and putting the crushed stone particles into the primary mixed material obtained in the step S1, and stirring to obtain the super-retarding concrete.

Wherein the primary mixed material is prepared by the following steps:

Examples 2 to 8

The concrete was prepared in different parts by weight of each component as compared with example 1, and the detailed numerical values are shown in table 2 (1 part by weight =1 kg).

TABLE 2

Comparative example 1: this comparative example differs from example 1 in that: the concrete does not contain retarder.

Comparative example 2: this comparative example differs from example 1 in that: the retarder in the concrete is formed by mixing sodium citrate and sodium gluconate according to the weight ratio of 3: 2:

comparative example 3: this comparative example differs from example 1 in that: the gel material, the broken stone, the water reducing agent and the retarder in the formula are all mixed at one time and are uniformly stirred.

Comparative example 4: this comparative example differs from example 1 in that: the retarder in the formula is directly formed by mixing sodium citrate, sodium gluconate, phosphogypsum, fly ash and carbide slag all at one time.

Comparative example 5: this comparative example differs from example 1 in that: in the retarder, the total weight of sodium citrate and sodium gluconate in the retarder accounts for 50% of the retarder by weight, and the total weight of phosphogypsum, fly ash and carbide slag accounts for 50% of the retarder by weight.

Comparative example 6: this comparative example differs from example 1 in that: in the retarder, the total weight of the sodium citrate and the sodium gluconate accounts for 30 percent of the retarder by weight, and the total weight of the phosphogypsum, the fly ash and the carbide slag accounts for 70 percent of the retarder by weight.

Performance detection test:

concrete was prepared according to the methods of preparation examples 1 to 6, examples 1 to 10 and comparative examples 1 to 6, and the properties of the concrete were measured according to the following criteria, and the results are shown in Table 3.

1. Initial setting time and final setting time: testing according to GB/T1346-2001, inspection method for water consumption, setting time and stability of standard consistency of cement;

2. compressive strength: measuring according to GB/T50080-2002 'common concrete mixture performance test method';

3. and (3) slump of discharging: testing according to GB/T50204-2002 acceptance limit for construction quality of concrete structural engineering and GBJ107-87 evaluation standard for concrete strength test.

4. Impermeability: the determination is carried out according to GB 50164 concrete quality control Standard;

TABLE 3 results of performance test of ultra-retarded concrete in examples 1-10 and comparative examples 1-6

Analysis of results

By combining the performance test data of example 1 and comparative example 1, it can be seen that the initial setting time and the final setting time of the concrete can be effectively delayed by adding the coagulant into the concrete under the condition that other components and the preparation method are not changed. This results from the ability of the concrete to coat the surface of the concrete particles with a layer of membrane water, which enhances the fluidity of the concrete and thus extends the initial setting time and final setting time of the concrete described herein.

By combining the performance test data of example 1 and comparative example 2, it can be seen that the super-retarding concrete can be produced by only adding sodium citrate and sodium gluconate to the concrete, but the strength of the concrete is reduced to a certain extent.

By combining the performance test data of example 1, preparation example 1 and comparative example 3, it can be seen that the concrete prepared by directly mixing the various components of the retarder of the present invention has a retardation time meeting the requirement of retardation within 48 hours, but the concrete prepared in this way has a lower compressive strength. The result is that the components in the concrete are not mixed uniformly, so that the concrete can meet the requirement on the retardation effect, but the compressive strength of the concrete can not meet the requirement.

Combining the performance test data of example 1, preparation example 1 and comparative example 4, it can be seen that the concrete prepared by directly mixing the various components of the retarder of the present invention has a compressive strength that can meet the use requirements of C30 concrete, but the initial setting time and final setting time of the concrete prepared in this way are both short. This is because the components of the retarder are not mixed well, so that the retarding effect of the retarder is weak, and the initial setting time and the final setting time of the concrete are prolonged.

By combining the performance detection data of example 1, preparation example 1 and comparative example 5, it can be seen that the retarded soil prepared by the method has prolonged retardation time, but the compressive strength of the retarded soil is reduced, so that the retarded soil has a risk that the compressive strength does not meet the requirement. This is a result of the excessive proportion of sodium citrate and sodium gluconate in the retarder, which results in a decrease in the compressive strength of the concrete.

By combining the performance test data of example 1, preparation example 1 and comparative example 6, it can be seen that the retardation time of the retardation soil prepared by the invention is shortened to some extent, but the compressive strength of the retardation soil is increased by reducing the proportion of sodium citrate and sodium gluconate in the retardation agent of the invention and increasing the proportion of phosphogypsum, fly ash and carbide slag. This is because the ratio of sodium citrate to sodium gluconate in the retarder is too small, and the retarder has a poor retarding effect.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. The super-retarding concrete is characterized by comprising the following components in parts by weight: 340-360 parts of a gel material, 700-900 parts of artificial sand, 900-1200 parts of broken stone, 7-8 parts of a water reducing agent, 8-10 parts of a retarder and 150-190 parts of water; the gel material is formed by mixing cement, mineral powder and coal ash, the weight of the mineral powder and the coal ash in the gel material accounts for not less than 10% of the weight of the gel material, the total weight of the mineral powder and the coal ash in the gel material accounts for 20-50% of the weight of the gel material, and the retarder is prepared from sodium citrate, sodium gluconate, phosphogypsum, coal ash and carbide slag according to the weight ratio of 24:16:45:12: 3;

the retarder is prepared by the following steps: firstly mixing sodium citrate and sodium gluconate at normal temperature, then standing the mixed solution of the sodium citrate and the sodium gluconate for at least 3 minutes, sequentially adding phosphogypsum, then stirring and fully stirring the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, then sequentially adding fly ash and carbide slag into the mixture of the sodium citrate, the sodium gluconate and the phosphogypsum, and finally placing a retarder with the fly ash and the carbide slag into a storage box for storage for later use.

2. The super-retarding concrete as claimed in claim 1, which comprises the following components in parts by weight: 210 parts of cement, 70 parts of mineral powder, 70 parts of coal ash, 800 parts of artificial sand, 1050 parts of broken stone, 7.7 parts of a water reducing agent, 9.0 parts of a retarder and 165 parts of water.

3. The super retarding concrete according to claim 1 or 2, wherein the crushed stones are continuously graded crushed stones, and the diameter of the crushed stones is 5-15 mm.

4. The super-retarding concrete of claim 3, wherein the sodium citrate and the sodium gluconate are both analytically pure.

5. The super retarding concrete according to claim 4, wherein the water reducing agent is a polyhydroxy water reducing agent, and the water reducing rate is 25-35%.

6. The super-retarding concrete according to claim 5, wherein the phosphogypsum is solid waste residue generated when phosphorite is treated by sulfuric acid in phosphoric acid production, the water content is 22-25%, and the particle size is less than or equal to 0.2 mm.

7. The super-retarding concrete according to claim 6, wherein the acetylene sludge is a sludge obtained by hydrolyzing calcium carbide to obtain acetylene gas and containing calcium hydroxide as a main component, the solid content is not less than 60%, the water content is 35-40%, and the particle size is not more than 0.2 mm.

8. The method for preparing the ultra-retarded concrete according to any one of claims 1 to 7, which is characterized by comprising the following steps:

wherein the primary mixed material is prepared by the following steps: