A high-performance concrete and its preparation method

Abstract

The present invention belongs to the technical field of concrete, and particularly relates to a high-performance concrete and a preparation method thereof. The concrete comprises the following raw materials in parts by weight: 200-230 parts of cement, 10-20 parts of modified bentonite, 10-20 parts of nano-potassium feldspar powder, 650-700 parts of fine aggregate, 950-1000 parts of coarse aggregate, 30-40 parts of mineral powder, 30-40 parts of fly ash, 5-10 parts of water reducing agent, and 140-150 parts of water. The concrete of the present invention has more excellent mechanical properties and wear resistance. Specifically, after 28 days of curing, the compressive strength of the concrete is higher than 85.7 MPa, the flexural strength is higher than 9.5 MPa, the splitting strength is higher than 8.6 MPa, and the wear amount is lower than 0.24 kg / m 2 .

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to a high-performance concrete and a preparation method thereof. Background Art

[0002] At present, one of the most widely used building materials in China is concrete. Concrete is a general term for engineering composite materials in which aggregate is cemented into a whole by cementitious materials. Traditional concrete mainly includes components such as cement, sand, aggregate, water, etc. The microstructure of the concrete prepared with the above components is relatively rough, its mechanical properties are limited to a certain extent, and it usually performs poorly in terms of wear resistance. With the diversification of concrete application scenarios, higher requirements are put forward for the mechanical properties and wear resistance of concrete.

[0003] Bentonite is a natural pozzolanic material and a common highly expansive clay, with montmorillonite as its main component. Due to its characteristics such as cation exchangeability, expansibility, and plasticity, bentonite is widely used in the technical field of building materials. However, studies have shown that although incorporating bentonite into concrete can reduce the initial cracks inside the concrete and improve the crack resistance and deformation ability of the concrete, it will reduce the compressive strength and flexural strength of the concrete.

[0004] Potassium feldspar powder is a powder made from potassium-rich silicate minerals. It has the advantages of low melting point, long melting interval time, high melting viscosity, and small fluidity, and is thus applied to the preparation of concrete. However, it is found that due to its own fragility, potassium feldspar powder will affect the mechanical properties and wear resistance of concrete.

[0005] Based on the above background, the present invention conducts a deeper research on the mechanical properties and wear resistance of concrete to accelerate the application of bentonite and potassium feldspar powder in concrete. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a high-performance concrete, which has excellent wear resistance and high mechanical properties.

[0007] Another purpose of the present invention is to provide a preparation method for the high-performance concrete, and the preparation process is simple.

[0008] One of the purposes of the present invention is achieved by adopting the following technical solutions:

[0009] A high-performance concrete, comprising the following raw materials in parts by weight: 200 - 230 parts of cement, 10 - 20 parts of modified bentonite, 10 - 20 parts of nano potassium feldspar powder, 650 - 700 parts of fine aggregate, 950 - 1000 parts of coarse aggregate, 30 - 40 parts of mineral powder, 30 - 40 parts of fly ash, 5 - 10 parts of water reducing agent, and 140 - 150 parts of water;

[0010] The preparation process of the modified bentonite is as follows:

[0011] (1) Take bentonite and add it to an aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride for heat treatment to obtain pretreated bentonite;

[0012] (2) Add the pretreated bentonite, manganese nitrate, and iron nitrate in step (1) to water to obtain a mixed solution A; add sodium carbonate and sodium phosphate to water to obtain a mixed solution B;

[0013] (3) Heat the mixed solution A in step (2) to 80 - 90 °C, and then add the mixed solution B in step (2) under stirring conditions for heat reaction. After the reaction is completed, collect the product through purification, and calcine the product to obtain the modified bentonite.

[0014] Preferably, the fine aggregate is natural river sand with a particle size of 1 - 2 mm; the coarse aggregate is first - graded crushed stone with a particle size of 5 - 20 mm; the mineral powder is S95 - grade slag powder; the coal ash powder is grade I fly ash.

[0015] Preferably, in step (1), the dosage ratio of the bentonite to the aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride is 1 g:(10 - 15) mL; the concentration of the aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride is 25 - 32 g / L.

[0016] Preferably, in step (1), the temperature of the heat treatment is 50 - 60 °C, and the time of the heat treatment is 2.5 - 4 h.

[0017] Preferably, in step (2), the mass ratio of the pretreated bentonite, manganese nitrate, iron nitrate, and water is 1:(0.5 - 1.5):(1 - 2):(15 - 20).

[0018] Preferably, in step (2), the mass ratio of sodium carbonate, sodium phosphate, and water is 1:(0.2 - 0.4):(5 - 7).

[0019] Preferably, in step (3), the mass ratio of the pretreated bentonite in the mixed solution A to sodium carbonate in the mixed solution B is 1:(1 - 1.5);

[0020] Preferably, in step (3), the temperature of the heat reaction is 80 - 90 °C, and the time of the heat reaction is 4 - 6 h.

[0021] Preferably, in step (3), the temperature of the calcination is 200 - 300 °C, and the time of the calcination is 5 - 7 h.

[0022] Preferably, the water - reducing agent is a polycarboxylate water - reducing agent.

[0023] More preferably, the polycarboxylate water reducer is PCE-102 polycarboxylate water reducer.

[0024] The second object of the present invention is achieved by the following technical solutions:

[0025] The preparation method of the above high-performance concrete includes the following steps:

[0026] According to the above weight ratio, mix the fine aggregate and the coarse aggregate evenly, and then add water, coal ash powder, cement, mineral powder, water reducer, modified bentonite, and nano-potassium feldspar powder and mix them evenly.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The modified bentonite of the present invention has high stability and wear resistance. Specifically, adding octadecyl bis(hydroxyethyl)methyl ammonium chloride to bentonite weakens the binding force between the bentonite layers; then further reacting to allow manganese and iron ions to enter the bentonite layers, and stable iron-manganese oxides are formed after calcination, thereby enhancing the stability and wear resistance of bentonite. In addition, the modified bentonite also has good film-forming properties, and its combination with nano-potassium feldspar can improve the bonding strength between cement and aggregate, thereby increasing the locking force between aggregates and achieving the purpose of improving the mechanical properties of concrete.

[0029] The concrete of the present invention has more excellent mechanical properties and wear resistance. Specifically, after 28 days of curing, the compressive strength of the concrete is higher than 85.7 MPa, the flexural strength is higher than 9.5 MPa, the splitting strength is higher than 8.6 MPa, and the wear amount is lower than 0.24 kg / m2. Specific Embodiments

[0030] The following content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the protection scope of the present invention. The specific conditions not specified in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, unless otherwise specified, are all conventional products obtained through commercial channels.

[0031] The cement involved in the present invention is 42.5 ordinary Portland cement; the fine aggregate is natural river sand with a particle size of 1-2 mm; the coarse aggregate is first-grade crushed stone with a particle size of 5-20 mm; the mineral powder is S95-grade slag powder with a density of 2.9 g / cm3, a specific surface area of 450 m2 / kg, a water content of 0.2%, and a 28-day activity index of 95%; the coal ash powder is grade I fly ash; the polycarboxylate water reducer is PCE-102 polycarboxylate water reducer.

[0032] 1. Preparation Examples

[0033] Preparation Example 1

[0034] Preparation Example 1 provides a modified bentonite, and the specific preparation process is as follows:

[0035] (1) According to the dosage ratio of bentonite to the aqueous solution of octadecyl bis(hydroxyethyl)methylammonium chloride of 1 g:12 mL, take bentonite and add it to the aqueous solution of 30 g / L octadecyl bis(hydroxyethyl)methylammonium chloride, and heat-treat at 54 °C for 3 h to obtain pretreated bentonite.

[0036] (2) According to the mass ratio of pretreated bentonite, manganese nitrate, iron nitrate, and water of 1:1:1.5:18, add the pretreated bentonite, manganese nitrate, and iron nitrate in step (1) to water to obtain a mixed solution A;

[0037] According to the mass ratio of sodium carbonate, sodium phosphate, and water of 1:0.3:6, add sodium carbonate and sodium phosphate to water to obtain a mixed solution B.

[0038] (3) Heat the mixed solution A in step (2) to 85 °C, and then add the mixed solution B in step (2) under stirring conditions, where the mass ratio of the pretreated bentonite in the mixed solution A to sodium carbonate in the mixed solution B is 1:1. Heat and react at 85 °C for 5 h. After the reaction is completed, filter, wash, and dry, collect the product, and calcine the product at 220 °C for 5.7 h to obtain the modified bentonite.

[0039] Preparation Example 2

[0040] Preparation Example 2 provides a modified bentonite, and the specific preparation process is as follows:

[0041] (1) According to the dosage ratio of bentonite to the aqueous solution of octadecyl bis(hydroxyethyl)methylammonium chloride of 1 g:15 mL, take bentonite and add it to the aqueous solution of 32 g / L octadecyl bis(hydroxyethyl)methylammonium chloride, and heat-treat at 60 °C for 2.5 h to obtain pretreated bentonite.

[0042] (2) According to the mass ratio of pretreated bentonite, manganese nitrate, iron nitrate, and water of 1:1.5:2:20, add the pretreated bentonite, manganese nitrate, and iron nitrate in step (1) to water to obtain a mixed solution A;

[0043] According to the mass ratio of sodium carbonate, sodium phosphate, and water of 1:0.4:7, add sodium carbonate and sodium phosphate to water to obtain a mixed solution B.

[0044] (3) Heat the mixed solution A in step (2) to 90 °C, and then add the mixed solution B in step (2) under stirring conditions, where the mass ratio of the pretreated bentonite in the mixed solution A to sodium carbonate in the mixed solution B is 1:1.2. Heat and react at 90 °C for 4 h. After the reaction is completed, filter, wash, and dry, collect the product, and calcine the product at 300 °C for 5 h to obtain modified bentonite.

[0045] Preparation Example 3

[0046] Preparation Example 3 provides a modified bentonite, and the specific preparation process is as follows:

[0047] (1) According to the dosage ratio of bentonite to the aqueous solution of octadecyl bis(hydroxyethyl)methylammonium chloride of 1 g:10 mL, take bentonite and add it to the aqueous solution of 25 g / L octadecyl bis(hydroxyethyl)methylammonium chloride, and heat-treat at 50 °C for 4 h to obtain pretreated bentonite.

[0048] (2) According to the mass ratio of pretreated bentonite, manganese nitrate, iron nitrate, and water of 1:0.5:1:15, add the pretreated bentonite, manganese nitrate, and iron nitrate in step (1) to water to obtain a mixed solution A;

[0049] According to the mass ratio of sodium carbonate, sodium phosphate, and water of 1:0.2:5, add sodium carbonate and sodium phosphate to water to obtain a mixed solution B.

[0050] (3) Heat the mixed solution A in step (2) to 80 °C, and then add the mixed solution B in step (2) under stirring conditions, where the mass ratio of the pretreated bentonite in the mixed solution A to sodium carbonate in the mixed solution B is 1:1.5. Heat and react at 80 °C for 6 h. After the reaction is completed, filter, wash, and dry, collect the product, and calcine the product at 200 °C for 7 h to obtain modified bentonite.

[0051] 2. Examples

[0052] Example 1

[0053] Example 1 provides a high-performance concrete, which is composed of the following raw materials in parts by weight: 210 parts of cement, 12 parts of modified bentonite prepared in Preparation Example 1, 15 parts of nano-potassium feldspar powder, 680 parts of fine aggregate, 970 parts of coarse aggregate, 33 parts of mineral powder, 36 parts of fly ash, 7 parts of polycarboxylate water reducer, and 142 parts of water.

[0054] Example 1 also provides a preparation method of the above high-performance concrete, which is as follows:

[0055] According to the above weight ratio, mix the fine aggregate and the coarse aggregate evenly, and then add water, coal ash powder, cement, mineral powder, polycarboxylate water reducer, modified bentonite, and nano-potassium feldspar powder and mix evenly.

[0056] Example 2

[0057] Example 2 provides a high-performance concrete, which is composed of the following raw materials in parts by weight: 230 parts of cement, 20 parts of modified bentonite prepared in Preparation Example 2, 20 parts of nano-potassium feldspar powder, 700 parts of fine aggregate, 1000 parts of coarse aggregate, 40 parts of mineral powder, 40 parts of fly ash, 10 parts of polycarboxylate water reducer, and 150 parts of water.

[0058] Example 2 also provides a method for preparing the above high-performance concrete, which is specifically as follows:

[0059] According to the above weight ratio, mix the fine aggregate and the coarse aggregate evenly, and then add water, coal ash powder, cement, mineral powder, polycarboxylate water reducer, modified bentonite, and nano-potassium feldspar powder and mix evenly to obtain the product.

[0060] Example 3

[0061] Example 3 provides a high-performance concrete, which is composed of the following raw materials in parts by weight: 200 parts of cement, 10 parts of modified bentonite prepared in Preparation Example 3, 10 parts of nano-potassium feldspar powder, 650 parts of fine aggregate, 950 parts of coarse aggregate, 30 parts of mineral powder, 30 parts of fly ash, 5 parts of polycarboxylate water reducer, and 140 parts of water.

[0062] Example 3 also provides a method for preparing the above high-performance concrete, which is specifically as follows:

[0063] According to the above weight ratio, mix the fine aggregate and the coarse aggregate evenly, and then add water, coal ash powder, cement, mineral powder, polycarboxylate water reducer, modified bentonite, and nano-potassium feldspar powder and mix evenly to obtain the product.

[0064] 3. Comparative Examples

[0065] Comparative Example 1

[0066] Comparative Example 1 provides a concrete, which is composed of the following raw materials in parts by weight: 210 parts of cement, 12 parts of bentonite, 15 parts of nano-potassium feldspar powder, 680 parts of fine aggregate, 970 parts of coarse aggregate, 33 parts of mineral powder, 36 parts of fly ash, 7 parts of polycarboxylate water reducer, and 142 parts of water. The rest is the same as that of Example 1.

[0067] Comparative Example 2

[0068] Comparative Example 2 provides a concrete, which is composed of the following raw materials in parts by weight: 210 parts of cement, 12 parts of modified bentonite prepared in Preparation Example 1, 15 parts of potassium feldspar powder, 680 parts of fine aggregate, 970 parts of coarse aggregate, 33 parts of mineral powder, 36 parts of fly ash, 7 parts of polycarboxylate water reducer, and 142 parts of water. The rest is the same as that of Example 1.

[0069] Comparative Example 3

[0070] Comparative Example 3 provides a kind of concrete, which is composed of the following raw materials in parts by weight: 210 parts of cement, 27 parts of modified bentonite prepared in Preparation Example 1, 680 parts of fine aggregate, 970 parts of coarse aggregate, 33 parts of mineral powder, 36 parts of fly ash, 7 parts of polycarboxylate water reducer, and 142 parts of water. The rest is the same as that in Example 1.

[0071] Comparative Example 4

[0072] Comparative Example 4 provides a kind of concrete, which is composed of the following raw materials in parts by weight: 210 parts of cement, 27 parts of nano-potassium feldspar powder, 680 parts of fine aggregate, 970 parts of coarse aggregate, 33 parts of mineral powder, 36 parts of fly ash, 7 parts of polycarboxylate water reducer, and 142 parts of water. The rest is the same as that in Example 1.

[0073] 4. Test Example

[0074] The concretes prepared in Examples 1 - 3 and Comparative Examples 1 - 4 were cured for 28 d under standard conditions and then subjected to performance tests as follows:

[0075] Compressive strength, flexural strength, and splitting strength: The tests were carried out according to the method of GB / T50081 - 2019, and the experimental results are shown in Table 1;

[0076] Wear resistance: The tests were carried out according to the method of JTGE30 - 2005, and the experimental results are shown in Table 1.

[0077]

[0078] It can be seen from Table 1 that the concretes prepared in Examples 1 - 3 have greater compressive strength, flexural strength, and splitting strength, and smaller wear amount. The above results show that the concretes prepared in Examples 1 - 3 have more excellent mechanical properties and wear resistance.

[0079] It can be seen from the data in Table 1 that in Comparative Example 1, the modified bentonite was replaced by bentonite; in Comparative Example 2, the nano-potassium feldspar powder was replaced by potassium feldspar powder; in Comparative Example 3, the nano-potassium feldspar was omitted and the amount of modified bentonite was increased; in Comparative Example 4, the modified bentonite was omitted and the amount of nano-potassium feldspar was increased. The mechanical properties of the prepared concretes were significantly reduced. The above results show that the combined use of nano-potassium feldspar and modified bentonite can effectively improve the mechanical properties of concrete. This is because the modified bentonite has good film-forming properties, and its combined use with nano-potassium feldspar can improve the bonding strength between cement and aggregate, thereby increasing the locking force between aggregates and achieving the purpose of improving the mechanical properties of concrete.

[0080] Furthermore, the abrasion resistance of the concrete prepared in Comparative Example 1 and Comparative Example 4 is significantly reduced. The above results show that the modified bentonite of the present invention can affect the abrasion resistance of concrete. In the present invention, octadecyl bis(hydroxyethyl) methyl ammonium chloride is added to bentonite, which weakens the binding force between the bentonite layers; then further reaction is carried out to allow manganese and iron ions to enter the bentonite layers, and stable iron-manganese oxides are formed after calcination, thereby enhancing the stability and abrasion resistance of bentonite.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. The basic principles and main features of the present invention have been described in the above with specific implementation schemes. On the basis of the present invention, some modifications or replacements can be made, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the present invention claimed.

Claims

1. A high-performance concrete, characterized in that, It comprises raw materials in the following parts by weight: 200 - 230 parts of cement, 10 - 20 parts of modified bentonite, 10 - 20 parts of nano potassium feldspar powder, 650 - 700 parts of fine aggregate, 950 - 1000 parts of coarse aggregate, 30 - 40 parts of mineral powder, 30 - 40 parts of fly ash, 5 - 10 parts of water reducing agent, and 140 - 150 parts of water; The modified bentonite is prepared through the following process: (1) Take bentonite and add it to an aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride for heat treatment to obtain pretreated bentonite; (2) Add the pretreated bentonite, manganese nitrate, and iron nitrate in step (1) to water to obtain mixed solution A; add sodium carbonate and sodium phosphate to water to obtain mixed solution B; (3) Heat up the mixed solution A in step (2) to 80 - 90 °C, then add the mixed solution B in step (2) under stirring conditions for heat reaction. After the reaction is completed, collect the product through purification, and calcine the product to obtain modified bentonite.

2. The high-performance concrete according to claim 1, wherein In step (1), the dosage ratio of the bentonite to the aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride is 1 g:(10 - 15) mL; the concentration of the aqueous solution of octadecyl bis(hydroxyethyl) methyl ammonium chloride is 25 - 32 g / L.

3. The high-performance concrete according to claim 1, wherein In step (1), the temperature of the heat treatment is 50 - 60 °C, and the time of the heat treatment is 2.5 - 4 h.

4. The high-performance concrete according to claim 1, wherein, In step (2), the mass ratio of the pretreated bentonite, manganese nitrate, iron nitrate, and water is 1:(0.5 - 1.5):(1 - 2):(15 - 20).

5. The high-performance concrete according to claim 1, characterized in that, In step (2), the mass ratio of the sodium carbonate, sodium phosphate, and water is 1:(0.2 - 0.4):(5 - 7).

6. The high-performance concrete according to claim 1, characterized in that, In step (3), the mass ratio of the pretreated bentonite in the mixed solution A to the sodium carbonate in the mixed solution B is 1:(1 - 1.5).

7. The high-performance concrete according to claim 1, wherein In step (3), the temperature of the heat reaction is 80 - 90 °C, and the time of the heat reaction is 4 - 6 h.

8. The high-performance concrete according to claim 1, characterized in that, In step (3), the temperature of the calcination is 200 - 300 °C, and the time of the calcination is 5 - 7 h.

9. The high-performance concrete according to claim 1, wherein, The water reducing agent is a polycarboxylate water reducing agent.

10. The preparation method of the high-performance concrete according to any one of claims 1-9, characterized in that, It includes the following steps: According to the above parts by weight ratio, mix the fine aggregate and the coarse aggregate evenly, and then add water, coal ash powder, cement, mineral powder, water reducing agent, modified bentonite, and nano potassium feldspar powder and mix them evenly. That's it.

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