CN110372283B

CN110372283B - High-strength concrete and preparation method thereof

Info

Publication number: CN110372283B
Application number: CN201910788592.0A
Authority: CN
Inventors: 黎木平; 张伟; 陈华; 李洁文; 王群; 武银锋; 陈伟; 梁云靖; 宋海龙; 马凌宇; 易明明; 周世浩; 李敬; 陈小冬; 谭丰哲
Original assignee: Shenzhen Traffic Engineering Quality Supervision Station (shenzhen Traffic Engineering Cost Management Station Shenzhen Traffic Engineering Construction Safety Supervision Station); Shenzhen Traffic Engineering Test Center Co ltd
Current assignee: Shenzhen Traffic Engineering Quality Supervision Station (shenzhen Traffic Engineering Cost Management Station Shenzhen Traffic Engineering Construction Safety Supervision Station); Shenzhen Traffic Engineering Test Center Co ltd
Priority date: 2019-08-24
Filing date: 2019-08-24
Publication date: 2021-08-24
Anticipated expiration: 2039-08-24
Also published as: CN110372283A

Abstract

The invention relates to a high-strength concrete and a preparation method thereof, wherein the high-strength concrete comprises the following components in parts by mass: 200-250 parts of cement, 400-450 parts of sand, 700-750 parts of pebbles, 100-150 parts of fly ash, 50-100 parts of hydrated lime, 100-130 parts of kaolin, 80-100 parts of montmorillonite/cellulose compound, 10-15 parts of tackifier, 5-8 parts of water reducing agent and 170-230 parts of water. The invention aims to provide the high-strength concrete which can improve the strength of the concrete after the concrete is solidified and ensure the quality of a building; the invention also aims to provide a preparation method of the high-strength concrete.

Description

High-strength concrete and preparation method thereof

Technical Field

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

Background

The concrete is prepared by stirring a cementing material, coarse and fine aggregates and water, and then is subjected to certain procedures, such as: pouring, vibrating and forming, maintaining, finishing and the like. The concrete material has better performance, so that the concrete material becomes one of the building engineering materials with the largest use amount and the widest use range in the current building engineering. With the advance of urbanization in China, ultrahigh, ultra-deep and ultra-large scale building projects are emerging continuously, and higher requirements are put forward on concrete technology.

Chinese patent with publication number CN108101425A discloses a concrete and a preparation method thereof, which comprises the following components in parts by weight: 1040-1050 macadam, 755-765 sand, 230-240 cement, 70-80 mineral powder, 55-65 coal ash, 6-26 admixture and 175-185 water, wherein the particle size of the macadam is 5-25mm, the particle size of the sand is 2-3mm, and the preparation method of the concrete comprises A, preparing materials; B. stirring, the invention has the advantages of shortening the stirring time and preventing cracks.

The above prior art solutions have the following drawbacks: for the building engineering, the concrete strength is an important index of the concrete quality, particularly for large-scale buildings, the concrete strength is more important, the concrete can prevent cracks and meet the use requirements of common buildings, but for some buildings with high engineering quality requirements, the concrete strength is low and cannot meet the engineering requirements.

Disclosure of Invention

The invention aims to provide the high-strength concrete which can improve the strength of the concrete after the concrete is solidified and ensure the quality of a building; the invention also aims to provide a preparation method of the high-strength concrete.

The technical purpose of the invention is realized by the following technical scheme: the high-strength concrete comprises the following components in parts by weight: 200-250 parts of cement, 400-450 parts of sand, 700-750 parts of pebbles, 100-150 parts of fly ash, 50-100 parts of hydrated lime, 100-130 parts of kaolin, 80-100 parts of montmorillonite/cellulose compound, 10-15 parts of tackifier, 5-8 parts of water reducing agent and 170-230 parts of water, wherein the preparation method of the montmorillonite/cellulose compound comprises the following steps:

a. uniformly stirring 20 parts of montmorillonite, 5 parts of dichloroethane and 70 parts of water, then adding 6 parts of a compound containing a sulfonic acid functional group, fully stirring for 4 hours at 100 ℃, naturally cooling and filtering after stirring is finished, washing with absolute ethyl alcohol, drying a filter cake obtained after filtering, and grinding into powder for later use;

b. and (b) adding 20 parts of cellulose and 10 parts of the powder prepared in the step (a) into a reaction kettle, adding 50 parts of water, uniformly stirring, reacting at 160-200 ℃ for 1-3 h, naturally cooling to room temperature, filtering, washing a filter cake with absolute ethyl alcohol, drying the filter cake, and grinding into powder to obtain the montmorillonite/cellulose composite.

By adopting the technical scheme, cement and water form cement slurry, the cement slurry wraps the surfaces of sand and stone and fills gaps between the sand and the stone, and the cement slurry plays a role in lubricating before concrete is solidified and hardened, so that the concrete mixture has workability suitable for construction, and the hardened cement enables the concrete to have required strength. The sand and the stones are much cheaper than cement, the cost of the concrete is reduced as cheap filling materials, and the addition of the sand and the stones can improve the durability of the concrete and reduce adverse phenomena such as heating, drying shrinkage and the like of cement paste. The addition of the fly ash, the hydrated lime and the kaolin can improve the workability of concrete mixtures and improve the compactness, impermeability, chemical corrosion resistance and the like of concrete.

Montmorillonite is added into water, dichloroethane enables the montmorillonite to be uniformly dispersed in the water, and a compound containing a sulfonic acid functional group is added, so that the sulfonic acid functional group is grafted to the surface of the montmorillonite for enhancing the acidity of the montmorillonite due to the existence of abundant silicon hydroxyl on the surface of the montmorillonite and the reaction of the silicon hydroxyl and the sulfonic acid group. When the cellulose and the montmorillonite are added into the reaction kettle, the intensity of the glycosidic bond on the cellulose can be reduced and even broken, the hydrogen bond in the cellulose molecule is destroyed, the molecular chain of the cellulose is shortened, and the dispersibility of the cellulose in concrete can be improved. The cellulose after partial hydrolysis is compounded with montmorillonite by discontinuous short cellulose chains or continuous long cellulose chains, the montmorillonite/cellulose composite is added into concrete, and the montmorillonite/cellulose composite plays a role in preventing the micro cracks in a cement matrix from expanding and bearing tensile stress across the cracks, so that the tensile strength, the breaking strength and the breaking energy of the concrete are improved. In addition, because cellulose molecules and montmorillonite both contain hydroxyl groups, the hydroxyl groups can form hydrogen bonds with a large number of hydroxyl groups in a cement hydration product, so that the compactness of an interface is improved, the adhesion strength of the interface is enhanced, and the interface effect of fiber blocking and enhancing is enlarged.

After concrete is stirred, segregation and bleeding are possibly caused by high fluidity in the transportation and placement processes, so that the improvement is often realized by adding a tackifier, the cohesiveness and the cohesive force of a cement-based material can be increased by the tackifier, and the uniformity of the cement-based material and the performance of a hardened product are improved.

The water reducing agent can reduce the mixing water consumption under the condition of keeping the concrete slump constant basically, has a dispersing effect on cement particles after being added, can improve the workability, reduces the unit water consumption and improves the fluidity of concrete mixtures.

The invention is further provided with: the high-strength concrete comprises the following components in parts by weight: 225 parts of cement, 430 parts of sand, 715 parts of pebbles, 130 parts of fly ash, 80 parts of hydrated lime, 110 parts of kaolin, 94 parts of montmorillonite/cellulose composite, 13 parts of tackifier, 7 parts of water reducer and 220 parts of water.

By adopting the technical scheme, the concrete prepared according to the proportion has the best compressive strength.

The invention is further provided with: in the step a, the compound containing a sulfonic acid functional group at least comprises one of 2-aminobenzenesulfonic acid, 1-amino-2-naphthol-sodium sulfonate and methanesulfonic acid.

By adopting the technical scheme, abundant silicon hydroxyl groups exist on the surface of the montmorillonite, and the silicon hydroxyl groups can react with the sulfonic acid functional groups to graft the sulfonic acid functional groups onto the surface of the montmorillonite, so that the acidity of the montmorillonite is improved.

The invention is further provided with: the tackifier at least comprises one of polyacrylamide, acrylic emulsion and cellulose ether.

By adopting the technical scheme, the polyacrylamide is added into the aqueous solution, so that the viscosity of the aqueous solution can be improved, the polyacrylic acid can adsorb surrounding water molecules, and the adsorption and fixation of the polyacrylic acid to the mixed water molecules promote the extension of macromolecules, so that the viscosity of the mixed water and the viscosity of concrete are increased; the acrylic emulsion is added, so that the attraction among concrete particles can be improved, and extra ultrafine particles can be provided for cement paste, so that the movement of water molecules is further prevented, and the viscosity of the concrete is increased; the cellulose ether entangles the polymer molecules with each other, thereby increasing the apparent concentration of the concrete.

The invention is further provided with: the mass ratio of the polyacrylamide to the acrylic emulsion to the cellulose ether is 1.2: 1.9: 2.5.

by adopting the technical scheme, the tackifier prepared according to the proportion has the best tackifying effect on concrete, and the proportion is used as the optimal proportion of the tackifier in the invention.

The invention is further provided with: the water reducing agent is sodium lignosulphonate.

By adopting the technical scheme, the sodium lignosulfonate is a natural high-molecular polymer and has strong dispersing capacity, and the surface tension and the interfacial tension of water can be reduced by adding the sodium lignosulfonate into an aqueous solution. The sodium lignosulfonate has hydrophobic groups and hydrophilic groups, the hydrophobic groups are directionally adsorbed on the surfaces of cement particles, and the hydrophilic groups point to an aqueous solution to form a monomolecular or polymolecular adsorption membrane, so that the cement particles are mutually repelled due to the same charges on the surfaces and are dispersed, and redundant water is released from the particles to achieve the purpose of reducing water.

The invention is further provided with: the particle size of the stones is 10-15 mm.

By adopting the technical scheme, the stones with the particle sizes of 10-15 mm can meet the requirement on the strength of concrete.

The second technical purpose of the invention is realized by the following technical scheme: the method specifically comprises the following steps:

step 1, weighing cement, sand, pebble, fly ash, hydrated lime, kaolin and montmorillonite/cellulose compound according to the formula ratio, and uniformly mixing to obtain mixed powder;

step 2, adding a water reducing agent and water with a half formula amount into the mixed powder in the step 1, and uniformly stirring to obtain mixed slurry;

and 3, adding the tackifier and the water with the residual formula amount into the mixed slurry obtained in the step 2, and uniformly stirring to obtain the concrete.

By adopting the technical scheme, the components with the formula ratio are weighed and uniformly mixed, and then the water reducing agent and the water are added, so that the dispersibility of cement particles can be improved and the performance of concrete can be improved in the stirring process; after the operation of the step 2 is finished, the mixed slurry is placed for a certain time, and the performance of the concrete is seriously influenced by the segregation and bleeding of the concrete. Therefore, the tackifier is added in the step 3 to increase the cohesiveness and the cohesive force of the mixed slurry, so that the mixed slurry can not be dispersed, and the high-quality and uniform concrete can be formed.

In conclusion, the beneficial technical effects of the invention are as follows:

1. the montmorillonite/cellulose compound has the functions of preventing the micro cracks in the cement matrix from expanding and bearing tensile stress across the cracks, so that the tensile strength, the breaking strength and the breaking energy of the concrete are improved; in addition, because cellulose molecules and montmorillonite both contain hydroxyl groups, the hydroxyl groups can form hydrogen bonds with a large number of hydroxyl groups in a cement hydration product, so that the compactness of an interface is improved, the adhesion strength of the interface is enhanced, and the interface effect of fiber blocking enhancement is enlarged;

2. after concrete is stirred, segregation and bleeding are possibly caused by high fluidity in the transportation and placement processes, so that the improvement is often realized by adding a tackifier, the cohesiveness and the cohesive force of a cement-based material can be increased by the tackifier, and the uniformity of the cement-based material and the performance of a hardened product are improved;

3. the preparation method of the concrete is simple, and the high-quality and uniform concrete can be prepared.

Detailed Description

The present invention will be described in further detail with reference to examples.

Example 1

Table 1 shows the components and their masses of a high-strength concrete of example 1

The preparation method of the montmorillonite/cellulose composite comprises the following steps:

a. uniformly stirring 20 parts of montmorillonite, 5 parts of dichloroethane and 70 parts of water, then adding 6 parts of 2-aminobenzenesulfonic acid, fully stirring for 4 hours at 100 ℃, naturally cooling and filtering after stirring, washing with absolute ethyl alcohol, drying a filter cake obtained after filtering, and grinding into powder for later use;

b. and (b) adding 20 parts of cellulose and 10 parts of the powder prepared in the step (a) into a reaction kettle, adding 50 parts of water, uniformly stirring, reacting at 160 ℃ for 3 hours, naturally cooling to room temperature, filtering, washing a filter cake with absolute ethyl alcohol, drying the filter cake, and grinding into powder to obtain the montmorillonite/cellulose composite.

The preparation method of the high-strength concrete specifically comprises the following steps:

Example 2

Table 2 shows the components and their masses of a high-strength concrete of example 2

a. uniformly stirring 20 parts of montmorillonite, 5 parts of dichloroethane and 70 parts of water, then adding 6 parts of 1-amino-2-naphthol-sodium sulfonate, fully stirring for 4 hours at 100 ℃, naturally cooling and filtering after stirring, washing with absolute ethyl alcohol, drying a filter cake obtained after filtering, and grinding into powder for later use;

b. and (b) adding 20 parts of cellulose and 10 parts of the powder prepared in the step (a) into a reaction kettle, adding 50 parts of water, uniformly stirring, reacting at 180 ℃ for 2 hours, naturally cooling to room temperature, filtering, washing a filter cake with absolute ethyl alcohol, drying the filter cake, and grinding into powder to obtain the montmorillonite/cellulose composite.

The preparation method of the high-strength concrete is the same as that of example 1.

Example 3

Table 3 shows the components and the qualities of a high-strength concrete of example 3

a. uniformly stirring 20 parts of montmorillonite, 5 parts of dichloroethane and 70 parts of water, then adding 6 parts of methanesulfonic acid, fully stirring for 4 hours at 100 ℃, naturally cooling and filtering after stirring, washing with absolute ethyl alcohol, drying a filter cake obtained after filtering, and grinding into powder for later use;

b. and (b) adding 20 parts of cellulose and 10 parts of the powder prepared in the step (a) into a reaction kettle, adding 50 parts of water, uniformly stirring, reacting at 200 ℃ for 1h, naturally cooling to room temperature, filtering, washing a filter cake with absolute ethyl alcohol, drying the filter cake, and grinding into powder to obtain the montmorillonite/cellulose composite.

Example 4

Table 4 shows the components and their masses of a high-strength concrete of example 4

a. uniformly stirring 20 parts of montmorillonite, 5 parts of dichloroethane and 70 parts of water, then adding 3 parts of 2-aminobenzenesulfonic acid and 3 parts of 1-amino-2-naphthol-sodium sulfonate, fully stirring for 4 hours at 100 ℃, after stirring, naturally cooling, filtering, washing with absolute ethyl alcohol, drying a filter cake obtained after filtering, and grinding into powder for later use;

Example 5

Table 5 shows the components and their masses of a high-strength concrete of example 5

The preparation method of the montmorillonite/cellulose composite is the same as that of example 4;

Example 6

Table 6 shows the components and their masses of a high-strength concrete of example 6

Example 7

Table 7 shows the components and their masses of a high-strength concrete of example 7

Comparative example 1, a high strength concrete, differs from example 7 in that no montmorillonite/cellulose composite was added, otherwise the same as example 7.

Comparative example 2, a high strength concrete, was different from example 7 in that the reaction temperature in step b of the method for preparing a montmorillonite/cellulose composite was 140 ℃, and the other examples were the same as example 7.

Comparative example 3, a high strength concrete, was different from example 7 in that the reaction temperature in step b of the method for preparing a montmorillonite/cellulose composite was 220 ℃, and the other examples were the same as example 7.

Comparative example 4, a high strength concrete, was different from example 7 in that the reaction time in step b was 0.5h in the method for preparing a montmorillonite/cellulose composite, and the other example was the same as example 7.

Comparative example 5, a high strength concrete, was different from example 7 in that the reaction time in step b was 4 hours in the method for preparing a montmorillonite/cellulose composite, and the other examples were the same as example 7.

Comparative example 6, a high strength concrete prepared in the same formulation amount as in example 7, was prepared by:

step 1, weighing cement, sand, pebbles, fly ash, hydrated lime, kaolin, a montmorillonite/cellulose compound, a water reducing agent and a tackifier according to the formula ratio, and uniformly mixing to obtain mixed powder;

and 2, adding water with the formula amount into the mixed powder in the step 1, and uniformly stirring to obtain the concrete.

Examples 1-7, comparative examples 1-6 were conducted according to GB/T50080-2002 Standard test methods for general concrete mixture Properties.

TABLE 2 results of performance test of examples and comparative examples

According to the experimental results, the compressive strength of the concrete in the examples 1 to 7 is superior to that of the concrete in the comparative examples 1 to 6, and compared with the concrete in the comparative example 1, the compressive strength of the concrete in the example 7 is greatly improved by adding the montmorillonite/cellulose compound into the concrete. Example 7 compared with comparative example 2 and comparative example 3, the concrete prepared in example 7 has higher compressive strength, and comparative example 2 shows that the temperature is low, and cellulose is not hydrolyzed or has low hydrolysis degree, so that the montmorillonite/cellulose composite has poor dispersibility in the concrete and poor reinforcing effect on the concrete; comparative example 3 shows that the cellulose is hydrolyzed to a large extent at an excessively high temperature, and the cellulose is decomposed into short chain units, so that the strength of the cellulose is reduced and the reinforcing effect on concrete is not good. Example 7 compared with comparative examples 4 and 5, the concrete prepared in example 7 has higher compressive strength, the reaction time of comparative example 4 is short, and cellulose is not hydrolyzed or has low hydrolysis degree, so that the montmorillonite/cellulose composite has poor dispersibility in the concrete and poor reinforcing effect on the concrete; comparative example 5 the reaction time was long, the cellulose hydrolysis degree was large, and the glycosidic bond in the cellulose was broken, so that the cellulose was decomposed into small molecules, the strength was reduced, and thus the reinforcing effect on concrete was deteriorated. Comparative example 6 compared to example 7, the preparation method example 7 is superior to comparative example 6.

The present embodiment is only for explaining the present invention, and not for limiting the present invention, and those skilled in the art can make modifications without inventive contribution to the present embodiment as needed after reading the present specification, but all of which are protected by patent law within the scope of the claims of the present invention.

Claims

1. A high-strength concrete is characterized in that: the adhesive comprises the following components in parts by mass: 200-250 parts of cement, 400-450 parts of sand, 700-750 parts of pebbles, 100-150 parts of fly ash, 50-100 parts of hydrated lime, 100-130 parts of kaolin, 80-100 parts of montmorillonite/cellulose compound, 10-15 parts of tackifier, 5-8 parts of water reducing agent and 170-230 parts of water, wherein the preparation method of the montmorillonite/cellulose compound comprises the following steps:

b. adding 20 parts of cellulose and 10 parts of the powder prepared in the step a into a reaction kettle, adding 50 parts of water, uniformly stirring, reacting at 160-200 ℃ for 1-3 h, naturally cooling to room temperature, filtering, washing a filter cake with absolute ethyl alcohol, drying the filter cake, and grinding into powder to obtain a montmorillonite/cellulose compound; the tackifier is polyacrylamide, acrylic emulsion and cellulose ether; the mass ratio of the polyacrylamide to the acrylic emulsion to the cellulose ether is 1.2: 1.9: 2.5; in the step a, the compound containing a sulfonic acid functional group at least comprises one of 2-aminobenzenesulfonic acid, 1-amino-2-naphthol-sodium sulfonate and methanesulfonic acid.

2. The high strength concrete of claim 1, wherein: the adhesive comprises the following components in parts by mass: 225 parts of cement, 430 parts of sand, 715 parts of pebbles, 130 parts of fly ash, 80 parts of hydrated lime, 110 parts of kaolin, 94 parts of montmorillonite/cellulose composite, 13 parts of tackifier, 7 parts of water reducer and 220 parts of water.

3. The high strength concrete of claim 1, wherein: the water reducing agent is sodium lignosulphonate.

4. The high strength concrete of claim 1, wherein: the particle size of the stones is 10-15 mm.

5. A method for producing a high-strength concrete according to any one of claims 1 to 4, characterized in that: the method specifically comprises the following steps: