CN113200724B

CN113200724B - High-strength concrete and preparation method thereof

Info

Publication number: CN113200724B
Application number: CN202110656483.0A
Authority: CN
Inventors: 黄明毅
Original assignee: Fogang Chengkang Commercial Concrete Co ltd
Current assignee: Fogang Chengkang Commercial Concrete Co ltd
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2023-04-07
Anticipated expiration: 2041-06-11
Also published as: CN113200724A

Abstract

The application relates to the technical field of concrete, and particularly discloses high-strength concrete and a preparation method thereof. The high-strength concrete comprises the following components in parts by weight: 100-200 parts of cement; 400-500 parts of natural coarse aggregate; 300-400 parts of natural fine aggregate; 500-700 parts of recycled aggregate; 5-10 parts of a water reducing agent; 120-160 parts of a filler; 100-200 parts of water; 10-20 parts of fiber filler; the fiber filler is formed by mixing modified glutinous rice flour and lignocellulose; the modified glutinous rice flour is prepared by the following steps; cleaning glutinous rice, drying, and grinding to obtain glutinous rice flour; adding glutinous rice flour into citric acid for aging, and then drying to obtain primarily modified glutinous rice flour; and grinding the primarily modified glutinous rice flour again, baking, washing with deionized water after baking, and drying to obtain the modified glutinous rice flour. The high-strength concrete has the advantages of high compressive strength and good cracking resistance.

Description

High-strength concrete and preparation method thereof

Technical Field

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

Background

In recent years, the construction industry enters a high-speed development stage, along with the acceleration of urbanization process in the world, the demolition and the reconstruction of the original building are increased day by day, a large amount of waste concrete is generated, the waste concrete not only occupies land resources, but also occupies large land and treatment cost per year, so that the recycling of the waste concrete is more and more emphasized, and the development of recycled concrete is promoted.

In the raw materials of the concrete, the aggregate accounts for the largest proportion, the traditional aggregate adopts natural sandstone, and the recycled concrete uses part of recycled aggregate to replace the natural aggregate to prepare the recycled concrete. The recycled aggregate is an aggregate material obtained by crushing, cleaning and grading waste concrete and mixing the waste concrete with the grade according to a certain proportion.

In view of the above-mentioned related technologies, when the recycled concrete prepared by using a part of recycled aggregate instead of natural aggregate is actually used, the problems such as cracks are likely to occur, and the strength of the recycled aggregate concrete needs to be improved.

Disclosure of Invention

In order to improve the compression resistance and the crack resistance of the recycled concrete, the application provides the high-strength concrete and the preparation method thereof.

In a first aspect, the present application provides a high-strength concrete, which adopts the following technical scheme:

the high-strength concrete comprises the following components in parts by weight:

100-200 parts of cement;

400-500 parts of natural coarse aggregate;

300-400 parts of natural fine aggregate;

500-700 parts of recycled aggregate;

5-10 parts of a water reducing agent;

120-160 parts of a filler;

100-200 parts of water;

10-20 parts of fiber filler;

the fiber filler is formed by mixing modified glutinous rice flour and lignocellulose;

the modified glutinous rice flour is prepared by the following steps;

a, cleaning glutinous rice, drying and grinding to obtain glutinous rice flour;

b, adding the glutinous rice flour into citric acid for aging, and then drying to obtain primarily modified glutinous rice flour;

and c, grinding the primarily modified glutinous rice flour again, baking, washing with deionized water after baking, and drying to obtain the modified glutinous rice flour.

By adopting the technical scheme, the main component in the glutinous rice is starch, the citric acid is dehydrated after being heated to generate acid anhydride, the acid anhydride and the starch in the glutinous rice flour are subjected to esterification reaction, and the heating is continued to further react the citric acid anhydride and the starch, so that the citric acid diester starch is generated. After the modified glutinous rice flour particles are mixed with the lignocellulose, the modified glutinous rice flour particles can be well attached to the surface of a three-dimensional net structure formed by the lignocellulose, and the modified glutinous rice flour particles are filled in a concrete framework consisting of coarse aggregate and fine aggregate along with the dispersion of the lignocellulose in a concrete matrix. In the process of mixing with the filler for use, the composite material can also play a role in adsorbing part of the filler, and further reduce the generation of cracks in a concrete matrix, thereby improving the strength of the concrete and ensuring that the concrete is not easy to crack. Meanwhile, the modified glutinous rice flour has a good water reducing effect, and can further save the consumption of unit cement and reduce the cost when being used together with a water reducing agent.

Preferably, the high-strength concrete comprises the following components in parts by weight:

120-160 parts of cement;

440-480 parts of natural coarse aggregate;

330-360 parts of natural fine aggregate;

580-640 parts of recycled aggregate;

7-9 parts of a water reducing agent;

140-150 parts of a filler;

120-140 parts of water;

14-16 parts of fiber filler.

By adopting the technical scheme, the prepared concrete has better compression resistance and crack resistance by further optimizing the proportion of the raw materials.

Preferably, in the fibrous filler, the modified glutinous rice flour is prepared by the following raw materials in percentage by weight: the lignocellulose is 1 (1.2-2.0).

Further preferably, in the fibrous filler, the modified glutinous rice flour is prepared by the following steps of: the lignocellulose is 1 (1.5-1.7).

By adopting the technical scheme, the proportion of the modified glutinous rice flour and the lignocellulose is further optimized, the synergistic effect between the modified glutinous rice flour and the lignocellulose is fully exerted, and the compression resistance and the crack resistance of the prepared concrete are further improved.

Preferably, the filler is one or more of fly ash, slag powder and silica fume.

By adopting the technical scheme, the silica fume, the slag powder and the fly ash can be filled into the pores among the cement particles, and gel is generated with hydration products, so that the compressive strength, the breaking strength, the impact resistance and the wear resistance of the concrete can be obviously improved.

Preferably, the filler is formed by mixing silica fume and fly ash according to the weight ratio of 1 (3-5).

By adopting the technical scheme, the silica fume and the fly ash are compounded according to the proportion, and the silica fume and the fly ash can be better filled in gaps between cement and aggregate after being mixed with water, so that the compactness of concrete is improved, and the compression resistance and the crack resistance of the concrete are improved.

Preferably, the preparation steps of the recycled aggregate are as follows:

a1, crushing waste concrete, and sieving to obtain regenerated particles with the particle size of 5-20mm and regenerated micro powder with the particle size of less than 1 mm;

a2, mixing the regenerated micro powder with water, adding redispersible latex powder and sodium stearate, and stirring and mixing to obtain a reinforced liquid;

and A3, putting the regenerated particles into the strengthening solution for soaking and drying to obtain the regenerated aggregate.

By adopting the technical scheme, the regenerated micro powder in the strengthening liquid can be well filled in the cracks of the regenerated particles, so that the strength of the regenerated particles is improved, the prepared concrete has better compression resistance and crack resistance through strengthening treatment on the regenerated particles, the generation of the cracks in the concrete is reduced, and meanwhile, the regenerated aggregate obtained through strengthening treatment and other raw materials have good workability, so that the concrete mixture is easy to construct.

Preferably, in the step A2 of preparing the recycled aggregate, the weight ratio of the recycled micro powder, the water, the redispersible latex powder and the sodium stearate is 1 (2-3) to (0.1-0.3) to (0.05-0.10).

By adopting the technical scheme, when the strengthening liquid is prepared according to the proportion, the strengthening effect on the recycled aggregate is better, the strength of the recycled aggregate is greatly improved, and the compression resistance and the crack resistance of the prepared concrete are improved.

In a second aspect, the present application provides a method for preparing high-strength concrete, which adopts the following technical scheme:

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

s1, mixing cement, natural coarse aggregate, natural fine aggregate, recycled aggregate, a water reducing agent and part of water to obtain a mixture A;

s2, mixing the filler, the fiber filler and the balance of water to obtain a mixture B;

and S3, adding the mixture B into the mixture A, and stirring and mixing to obtain the high-strength concrete.

By adopting the technical scheme, the filler, the fiber filler and water are premixed and then are mixed into a concrete system, so that the filler and the fiber filler can be better filled in a gap between the filler and a concrete framework, and the mechanical strength of concrete is improved. The preparation method is simple, has low requirements on conditions, can well realize large-scale industrial production, has low requirements on labor force, and reduces the production cost.

Preferably, in the S1, the addition amount of water accounts for 60-70% of the total weight of water.

By adopting the technical scheme, in the preparation process of the concrete, the framework raw material and the filler raw material are premixed independently and then mixed, so that the dispersibility of the raw materials in a mixed system is improved, the filler raw material can be filled in the concrete framework more uniformly and fully, and the compression resistance and the crack resistance of the concrete are improved.

In summary, the present application has the following beneficial effects:

1. according to the application, the modified glutinous rice flour and the lignocellulose are mixed to form the fiber filler, the modified glutinous rice flour and the lignocellulose have good synergistic effect, the modified glutinous rice flour can be attached to the surface of the lignocellulose, and the lignocellulose is dispersed in a concrete matrix and filled in gaps inside concrete, so that the crack resistance and the pressure resistance of the prepared concrete are improved;

2. in the process of preparing the recycled aggregate, the recycled particles are reinforced by the reinforcing liquid taking the recycled micro powder as the main raw material, so that the recycled micro powder can be better filled in gaps on the surfaces of the recycled particles, the strength of the recycled particles is improved, and the crack resistance and the pressure resistance of the prepared concrete are further improved;

3. the coal ash and the silica fume are compounded to form the filler, so that the compression resistance and the crack resistance of the concrete are improved.

Detailed Description

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

The raw materials used in the examples of the present application are commercially available, except for the following specific descriptions:

the polycarboxylic acid high-efficiency water reducing agent is obtained from a corridor workshop Huajing novel building material limited company, the solid content is 98 +/-1 percent, the water reducing rate is more than or equal to 21 percent, and the polycarboxylic acid high-efficiency water reducing agent is of high-grade;

the lignocellulose is collected from Shijiazhuang Majie building materials Co., ltd, the product number is 11, and secondary products;

the fly ash is collected from a mineral product processing factory of Chuangwei in Lingshou county, the compressive strength is 36MPa, the model is CW2-5, and the cargo number is 189;

the slag powder is S105 grade slag powder from Tangshan Industrial building materials Co., ltd, has specific surface area of 430-450m2/kg and density of 2.8-3.0g/cm ³ The fluidity ratio is more than or equal to 88 percent, and the water content is less than or equal to 0.2 percent;

the silica fume is collected from Tuomalin mineral products, inc., shijiazhuang, 1250-mesh, CAS number 13983-17-0;

montmorillonite is collected from Tuolin mineral product processing factory in Lingshou county, 325 mesh, apparent viscosity of 100mPa.s, and density of 120g/cm ³ Cargo number TL-300;

the redispersible latex powder is obtained from Gallery stroke-equalizing energy-saving technology Limited company, model 8060, and the content is more than or equal to 98%;

sodium stearate is obtained from Shandong Liang New Material science and technology Co., ltd, model number LA-5S, CAS number 822-16-2.

Preparation example

Preparation A1

A modified glutinous rice flour is prepared by the following steps:

cleaning glutinous rice, drying at 80 ℃ until the water content is lower than 5%, grinding, and sieving by a 40-mesh sieve to obtain glutinous rice flour;

b, adding 1kg of glutinous rice flour into 1L of 35% citric acid, aging at 25 ℃ for 12h, and drying at 50 ℃ after aging until the water content is 10% to obtain the primarily modified glutinous rice flour;

and c, grinding the primarily modified glutinous rice flour again, baking for 8 hours at 120 ℃, washing for 2 times by using deionized water after baking is finished, and drying at 50 ℃ until the water content is lower than 5% to obtain the modified glutinous rice flour.

Preparation B1

The preparation method of the recycled aggregate comprises the following steps:

a2, mixing 10kg of regenerated micro powder with 10kg of water, adding 0.5kg of redispersible latex powder and 0.25kg of sodium stearate, and stirring and mixing for 20min at 50 ℃ at 1000r/min to obtain a strengthening solution;

and A3, putting 1kg of recycled particles into 5kg of strengthening solution, soaking for 2h, drying at 220 ℃ until the water content is lower than 5%, and cooling to 25 ℃ to obtain recycled aggregate.

Preparation examples B2 to B5

A recycled aggregate which is different from the recycled aggregate prepared in preparation example B1 in that in A2 in the preparation process of the recycled aggregate, the amounts of recycled micro powder, water, redispersible latex powder and sodium stearate are shown in Table 1.

TABLE 1 preparation examples B1 to B5 in A2 the amounts (kg) of the components used

Examples

Example 1

The high-strength concrete comprises the following components in parts by weight shown in Table 2, and is prepared by the following steps:

s1, stirring and mixing cement, natural coarse aggregate, natural fine aggregate, recycled aggregate, a water reducing agent and water accounting for 50% of the total weight of the water for 30min under the condition of 120r/min to obtain a mixture A;

s2, stirring and mixing the filler, the fiber filler and the balance of water for 25min under the condition of 200r/min to obtain a mixture B;

and S3, adding the mixture B into the mixture A, and continuously stirring for 40min under the condition of 160r/min to obtain the high-strength concrete.

Wherein the cement is ordinary portland cement, and the strength grade is 42.5;

the natural coarse aggregate is basalt macadam with the grain size of 5-20mm in continuous gradation;

the natural fine aggregate adopts natural medium sand in a II area, the fineness modulus is 2.5, and the mud content is less than 1.0 percent;

modified glutinous rice flour was prepared according to preparation example A1;

recycled aggregate was prepared from preparation example B1;

the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent.

Examples 2 to 6

A high-strength concrete, which is different from example 1 in that each component and the corresponding weight thereof are shown in table 2.

TABLE 2 Components and their weights (kg) in examples 1-6

Examples 7 to 11

A high-strength concrete, which is different from example 3 in that each component and the corresponding weight thereof are shown in table 3.

TABLE 3 Components and weights (kg) of examples 3, 7-11

Examples 12 to 21

A high-strength concrete, which is different from example 9 in that each component and the corresponding weight thereof are shown in table 4.

TABLE 4 compositions and weights (kg) thereof in examples 12-21

Example 22

A high-strength concrete, which is different from example 19 in that water is added in an amount of 60% by weight based on the total weight of water in S1 during the production of the high-strength concrete.

Example 23

A high-strength concrete, which is different from example 19 in that water is added in an amount of 65% by weight based on the total weight of water in S1 during the production of the high-strength concrete.

Example 24

A high-strength concrete, which is different from example 19 in that water is added in an amount of 70% by weight based on the total weight of water in S1 during the preparation of the high-strength concrete.

Example 25

A high-strength concrete, which is different from example 19 in that water is added in an amount of 80% by weight based on the total weight of water in S1 during the production of the high-strength concrete.

Examples 26 to 29

A high-strength concrete different from example 23 in the use of recycled aggregate, and the concrete correspondence relationship is shown in table 5.

TABLE 5 comparative table of recycled aggregate used in examples 26 to 29

Group of	Recycled aggregate
		Example 26	From preparation B2
Example 27	From preparation B3
		Example 28	From preparation B4
Example 29	From preparation B5

Comparative example

Comparative examples 1 to 8

A concrete, which differs from example 1 in that the components and their respective weights are shown in table 6.

TABLE 6 compositions and weights (kg) thereof in comparative examples 1-8

Performance test

Taking the concrete prepared in the examples 1-29 and the comparative examples 1-8 as test objects, making a standard test block by referring to GB/T50081-2019 Standard test method for mechanical Properties of common concrete, and measuring the compressive strength of the standard test block cured for 28 d; making a standard test block according to GB/T50081-2019 standard of common concrete mechanical property test method, testing the splitting tensile strength, observing whether each group of samples generate cracks or not, recording the lengths of the cracks, and counting the test results into the following table 7.

TABLE 7 results of Performance testing

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As can be seen from the test data in table 7: the high-strength concrete prepared by the embodiment of the application has better crack resistance and compression resistance, the compression strength of the high-strength concrete reaches more than 38.6MPa, and the splitting tensile strength of the high-strength concrete reaches more than 3.32 MPa. Wherein, the embodiment 27 is the best embodiment, the compression strength of the high-strength concrete prepared by the embodiment 27 can reach 43.2MPa, and the splitting tensile strength can reach 3.95MPa.

By combining example 1 and comparative examples 1 to 3, and by combining table 7, it can be seen that when the modified glutinous rice flour (i.e., comparative example 1) alone or the lignocellulose (i.e., comparative example 2) alone is used as the fibrous filler, the crack resistance and the compression resistance of the prepared concrete are reduced to different degrees compared with the concrete prepared by using the modified glutinous rice flour and the lignocellulose in combination (i.e., example 1) as the fibrous filler, which indicates that the modified glutinous rice flour and the lignocellulose have better synergistic promotion effect, and the crack resistance and the compression resistance of the prepared concrete can be obviously improved.

By combining examples 1-6 with comparative examples 4, 5, 7, and 8, and by combining table 7, it can be seen that the concrete prepared in the range of the raw material mixture ratio of the present application has better crack resistance and pressure resistance.

By combining the examples 3 and 7-11 and combining the table 7, in the process of preparing the concrete, when the fiber filler is formed by mixing the modified glutinous rice flour and the lignocellulose according to the weight ratio of 1 (1.2-2.0), the prepared concrete has better crack resistance and pressure resistance; when the fiber filler is formed by mixing the modified glutinous rice flour and the lignocellulose according to the weight ratio of 1 (1.5-1.7), the prepared concrete has better crack resistance and pressure resistance; particularly, when the fiber filler is formed by mixing the modified glutinous rice flour and the lignocellulose according to the weight ratio of 1.6, namely the example 9, the compressive strength of the prepared concrete can reach 40.5MPa, and the splitting tensile strength can reach 3.56MPa.

In combination with examples 9, 17-21 and Table 7, it can be seen that when silica fume and fly ash are mixed to form the filler according to the weight ratio of 1 (3-5) in the process of preparing concrete, the prepared concrete has better anti-cracking and anti-compression properties.

In the process of preparing recycled aggregate, the concrete prepared by combining examples 23 and 26-29 and table 7 has better crack resistance and compression resistance when the components and weight ratio range of the reinforcing liquid are that the recycled micro powder, the water, the redispersible latex powder and the sodium stearate are 1 (2-3) to (0.1-0.3) to (0.05-0.10). When the weight ratio of the regenerated micro powder to the water to the redispersible latex powder to the sodium stearate is 1.

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

Claims

1. The high-strength concrete is characterized by comprising the following components in parts by weight:

100-200 parts of cement;

400-500 parts of natural coarse aggregate;

300-400 parts of natural fine aggregate;

500-700 parts of recycled aggregate;

5-10 parts of a water reducing agent;

120-160 parts of a filler; the filler is one or more of fly ash, slag powder and silica fume;

100-200 parts of water;

10-20 parts of fiber filler;

the modified glutinous rice flour is prepared by the following steps;

a, cleaning glutinous rice, drying and grinding to obtain glutinous rice flour;

c, grinding the primarily modified glutinous rice flour again, baking, washing with deionized water after baking, and drying to obtain modified glutinous rice flour;

the preparation steps of the recycled aggregate are as follows:

a3, putting the regenerated particles into a strengthening solution for soaking, and drying to obtain regenerated aggregate;

in the preparation step A2 of the recycled aggregate, the weight ratio of the reinforcing solution to the recycled micro powder to the water to the redispersible latex powder to the sodium stearate is 1 (2-3) to (0.1-0.3) to (0.05-0.10).

2. The high-strength concrete according to claim 1, wherein the high-strength concrete comprises the following components in parts by weight:

120-160 parts of cement;

440-480 parts of natural coarse aggregate;

330-360 parts of natural fine aggregate;

580-640 parts of recycled aggregate;

7-9 parts of a water reducing agent;

140-150 parts of a filler;

120-140 parts of water;

14-16 parts of fiber filler.

3. The high-strength concrete according to claim 1, wherein in the fiber filler, the modified glutinous rice flour: the lignocellulose is 1 (1.2-2.0).

4. The high-strength concrete according to claim 1, wherein in the fiber filler, the modified glutinous rice flour: the lignocellulose is 1 (1.5-1.7).

5. The high-strength concrete according to claim 1, wherein the filler is formed by mixing silica fume and fly ash according to a weight ratio of 1 (3-5).

6. The method for preparing the high-strength concrete according to any one of claims 1 to 5, characterized by comprising the steps of:

7. The method for preparing high-strength concrete according to claim 6, wherein the water is added in an amount of 60-70% by weight based on the total weight of the water in S1.