A freeze-thaw resistant high-strength brick and a method for preparing the same

Abstract

The application relates to the field of building materials, and more particularly to a freeze-thaw resistant high-strength brick and a preparation method thereof. The freeze-thaw resistant high-strength brick comprises, in mass parts, at least: a gel material 90-130 parts, an aggregate system 160-200 parts, a freeze-thaw stable composition 8-20 parts, a water reducing agent 0.8-1.6 parts, an air entraining agent 0.1-0.5 parts, a rust inhibitor 0.5-1.5 parts, an adjusting agent 0.3-1 part, and water 30-60 parts. The freeze-thaw resistant high-strength brick prepared in the application not only has excellent freeze-thaw resistance and compressive strength, but also further improves the stability, salt freeze corrosion resistance, durability and service life of the brick in harsh environments, thereby obtaining excellent comprehensive performance to meet the demand of existing building materials for the brick.

Description

Technical Field

[0001] This application relates to the field of building materials, and more specifically mentions a freeze-thaw resistant high-strength brick and its preparation method. Background Technology

[0002] With the acceleration of urbanization, the requirements for building materials are constantly increasing. Especially in cold regions, road materials need to have excellent freeze-thaw resistance to cope with the challenges brought about by seasonal temperature changes. Traditional building materials such as cement and asphalt often exhibit poor durability in these environments, leading to increased costs for frequent maintenance and replacement. Therefore, developing a brick material with high compressive strength and excellent freeze-thaw resistance has become a key research focus.

[0003] Currently, various types of bricks exist on the market, such as traditional concrete bricks, which are widely used due to their low cost and simple production process. However, they perform poorly when faced with frequent freeze-thaw cycles, easily cracking or peeling, severely affecting their service life. To enhance the freeze-thaw resistance of concrete bricks, researchers have experimented with adding various chemical additives during the production process, such as air inclusion forming agents and waterproofing agents. These additives can improve the material's freeze-thaw resistance to some extent, but they may also bring some negative effects, such as increasing production costs and affecting other physical properties of the material (such as shrinkage). Polymer-modified cementitious composites, by combining organic polymers with cementitious materials, can significantly improve the toughness, crack resistance, and durability of the material. These materials not only have good freeze-thaw resistance but also provide high strength. However, the relatively poor stability of polymers limits their large-scale application. High-performance concrete bricks using special aggregates or admixtures can effectively improve the freeze-thaw resistance and mechanical properties of concrete by employing specific types of aggregates (such as lightweight aggregates) or incorporating mineral admixtures (such as silica fume, fly ash, etc.). However, this method requires strict selection of raw materials and involves a relatively complex production process.

[0004] Therefore, although existing technologies have improved the freeze-thaw resistance and strength of building materials to some extent, several shortcomings still exist. These problems mainly lie in the need to improve freeze-thaw resistance and stability, the urgent need to improve salt corrosion resistance, and the need to further enhance long-term durability and service life. Summary of the Invention

[0005] In summary, how to prepare a high-strength brick with superior overall performance has become a key research topic for those skilled in the art. Through continuous research on this type of high-strength brick, the applicant hereby proposes a freeze-thaw resistant high-strength brick and its preparation method. The freeze-thaw resistant high-strength brick prepared in this application not only maintains excellent freeze-thaw resistance and compressive strength, but also further improves the brick's stability, resistance to salt corrosion, and durability and service life in harsh environments, thereby achieving excellent overall performance to meet the existing building material requirements for this type of brick.

[0006] A freeze-thaw resistant high-strength brick, comprising, by weight, at least the following raw materials: 90-130 parts of gel material, 160-200 parts of aggregate system, 8-20 parts of freeze-thaw stabilized composition, 0.8-1.6 parts of water-reducing agent, 0.1-0.5 parts of air-entraining agent, 0.5-1.5 parts of rust inhibitor, 0.3-1 part of regulator, and 30-60 parts of water.

[0007] In a preferred embodiment, the mass ratio of the gel material, aggregate system and freeze-thaw stabilized composition is (100~120):(170~190):(10~18).

[0008] In a preferred embodiment, the mass ratio of the gel material, aggregate system and freeze-thaw stabilized composition is (100~110):(180~185):(13~16).

[0009] In a preferred embodiment, the gel material is a composition of P·II 52.5 silicate cement and P 42.5 sulfoaluminate cement.

[0010] In a preferred embodiment, the gel material is P·II 52.5 silicate cement and P 42.5 sulfoaluminate cement in a mass ratio of (6~9):(1~4).

[0011] In a preferred embodiment, the gel material is P·II 52.5 silicate cement and P 42.5 sulfoaluminate cement in a mass ratio of (7~8):(2~3).

[0012] In a preferred embodiment, the aggregate system is a composition of manufactured sand and basalt crushed stone.

[0013] In a preferred embodiment, the mass ratio of the manufactured sand to the basalt crushed stone is (10~14):(6~9).

[0014] In a preferred embodiment, the mass ratio of the manufactured sand to the basalt crushed stone is (11~12):(7~9).

[0015] In a preferred embodiment, the average particle size of the manufactured sand is 0.15~2.36mm.

[0016] In a preferred embodiment, the average particle size of the basalt gravel is 5-15 mm.

[0017] In a preferred embodiment, the average particle size of the basalt gravel is 7-10 mm.

[0018] In a preferred embodiment, the freeze-thaw stabilizing composition is a combination of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer, and zirconium borate.

[0019] In a preferred embodiment, the mass ratio of the mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer, and zirconium borate is (5~6.5):(2~3):(1~2).

[0020] In a preferred embodiment, the mass ratio of the mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer, and zirconium borate is (5.5~6):(2.2~2.6):(1~1.5).

[0021] In a preferred embodiment, the specific surface area of ​​the mercapto-modified clinoptilolite is 400~600 m² / g.

[0022] In a preferred embodiment, the average particle size of the zirconium borate is 60~100nm.

[0023] The freeze-thaw stabilizing composition incorporated in this application absorbs water molecules through micropores to maintain a liquid state at low temperatures, and then uses mesopores as a directional buffer layer to absorb the expansion stress of ice crystals. Furthermore, the Zn²⁺ in the copolymer forms ≡Si-O-Zn covalent bonds with the cement hydration product CSH, constructing an ionic cross-linked network on the pore surface. This preferentially reacts with SO₄²⁻ to generate highly soluble ZnSO₄, preventing the crystallization expansion of low-solubility materials, lowering the crystallization temperature of the salt solution, and blocking the microcrack propagation path through crack pinning effect, thereby improving the fracture toughness of the material. Adjusting the compatibility of the coefficient of thermal expansion with the cement matrix significantly reduces thermal mismatch stress. In conjunction with the ≡Si-O-Zr-B chemical bonds formed by the surface hydroxyl groups and CSH, the microcrack density after freeze-thaw is significantly reduced, enhancing melt resistance and overall stability.

[0024] In a preferred embodiment, the water-reducing agent is at least one of a high-efficiency polycarboxylate water-reducing agent or a naphthalene-based water-reducing agent.

[0025] In a preferred embodiment, the water-reducing agent is a high-efficiency polycarboxylate water-reducing agent.

[0026] In a preferred embodiment, the air-entraining agent is at least one of sodium α-olefin sulfonate, rosin resin triterpenoid saponins, polyethylene glycol oleate, and sodium dodecyl sulfate.

[0027] In a preferred embodiment, the air-entraining agent is sodium α-olefin sulfonate or polyethylene glycol oleate.

[0028] In a preferred embodiment, the air-entraining agent is sodium α-olefin sulfonate.

[0029] In a preferred embodiment, the rust inhibitor is at least one selected from calcium nitrite, sodium benzoate, lithium nitrate, and triethanolamine phosphate.

[0030] In a preferred embodiment, the rust inhibitor is calcium nitrite or sodium benzoate.

[0031] In a preferred embodiment, the rust inhibitor is calcium nitrite.

[0032] In a preferred embodiment, the regulator is at least one selected from hydroxyethyl cellulose, acrylamide copolymer, attapulgite clay colloid, and hydrophobic polyacrylic acid.

[0033] In a preferred embodiment, the regulator is hydroxyethyl cellulose or attapulgite clay colloid.

[0034] In a preferred embodiment, the regulator is hydroxyethyl cellulose.

[0035] In a preferred embodiment, the freeze-thaw resistant high-strength brick, by weight, further comprises: 0.3-3 parts of reinforcing agent, 3-10 parts of toughening agent, 2-5 parts of antifreeze agent, and 3-12 parts of composite additive.

[0036] In a preferred embodiment, the mass ratio of the gel material to the composite additive is (100~120):(6~11).

[0037] In a preferred embodiment, the mass ratio of the gel material to the composite additive is (100~110):(8~10).

[0038] In a preferred embodiment, the reinforcing agent is at least one selected from polypropylene fiber, glass fiber, and basalt fiber.

[0039] In a preferred embodiment, the reinforcing agent is glass fiber or basalt fiber.

[0040] In a preferred embodiment, the reinforcing agent is basalt fiber.

[0041] In a preferred embodiment, the toughening agent is at least one selected from styrene-butadiene rubber latex, epoxy resin latex, ethylene-vinyl acetate copolymer latex, and polyurethane latex.

[0042] In a preferred embodiment, the toughening agent is a styrene-butadiene rubber latex or an ethylene-vinyl acetate copolymer latex.

[0043] In a preferred embodiment, the toughening agent is a styrene-butadiene rubber latex.

[0044] In a preferred embodiment, the antifreeze is at least one selected from ethylene glycol, triethanolamine, and propylene carbonate.

[0045] In a preferred embodiment, the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxy siloxane copolymer.

[0046] In a preferred embodiment, the mass ratio of the methyl heptafluorobutyl acrylate to the epoxy siloxane copolymer is (5~8):(1~3).

[0047] In a preferred embodiment, the mass ratio of the methyl heptafluorobutyl acrylate to the epoxy siloxane copolymer is (6~7.5):(1.5~2.5).

[0048] In this application, the combined action of freeze-thaw stabilized composition and composite additives effectively regulates the water-salt phase transition behavior of the brick material system. While adsorbing ions, a multi-level protection mechanism is constructed in the material system, successfully achieving a balance between high mechanical strength and extreme environmental durability, and jointly blocking the penetration pathways of water and salt ions.

[0049] A method for preparing the above-mentioned freeze-thaw resistant high-strength brick specifically includes the following steps: S1: After drying the gel material, add it to a high-speed mixer, and then add the remaining raw materials in sequence and mix at a high speed of 500~600rpm for 10~20min; S2: After mixing, pour it into a mold and let it stand at room temperature for 10~12h, then cure it with steam at 50℃ / 95%RH for 22~24h, and then cure it at a medium temperature of 70~75℃ for 6~8h; S3: Finally, cure it in a curing chamber under standard curing conditions for 28 days to obtain the brick.

[0050] This application has practical significance and beneficial effects:

[0051] 1. The freeze-thaw resistant high-strength brick prepared in this application can not only maintain excellent freeze-thaw resistance and compressive strength, but also further improve the stability, salt corrosion resistance, durability and service life of the brick in harsh environments, thereby achieving excellent comprehensive performance to meet the existing building materials requirements for this type of brick.

[0052] 2. The freeze-thaw stabilizing composition incorporated in this application absorbs water molecules through micropores to maintain a liquid state at low temperatures, and then uses mesopores as a directional buffer layer to absorb the expansion stress of ice crystals; furthermore, the Zn²⁺ in the copolymer forms ≡Si-O-Zn covalent bonds with the cement hydration product CSH, constructing an ionic cross-linked network on the pore surface, preferentially reacting with SO4²⁻ to generate highly soluble ZnSO4, preventing the crystallization expansion of low-solubility materials, lowering the crystallization temperature of the salt solution, and blocking the microcrack propagation path through crack pinning effect, thereby improving the fracture toughness of the material, adjusting the thermal expansion coefficient and the compatibility with the cement matrix to significantly reduce thermal mismatch stress, and combining the ≡Si-O-Zr-B chemical bonds formed by the surface hydroxyl groups and CSH to significantly reduce the microcrack density after freeze-thaw, thereby enhancing the melt resistance and overall stability.

[0053] 3. In this application, the freeze-thaw stabilized composition and composite additives work together to effectively regulate the water-salt phase transition behavior of the brick material system. While adsorbing ions, a multi-level protection mechanism is constructed in the material system, successfully achieving a balance between high mechanical strength and extreme environmental durability, and jointly blocking the penetration paths of water and salt ions. Attached Figure Description

[0054] Figure 1 and Figure 2 This is a finished product image of the freeze-thaw resistant high-strength brick prepared according to the embodiments of this application. Detailed Implementation

[0055] Example 1: A freeze-thaw resistant high-strength brick, comprising, by weight, at least the following raw materials: 105 parts gel material, 182 parts aggregate system, 14.8 parts freeze-thaw stabilized composition, 1.1 parts water-reducing agent, 0.3 parts air-entraining agent, 0.8 parts rust inhibitor, 0.6 parts regulator, 40 parts water, 2.1 parts reinforcing agent, 5.5 parts toughening agent, 3.2 parts antifreeze agent, and 8.8 parts composite additive.

[0056] The gelling material is a composition of P·II 52.5 silicate cement and P 42.5 sulfoaluminate cement in a mass ratio of 8:2.5.

[0057] The aggregate system is a combination of manufactured sand and basalt crushed stone in a mass ratio of 11:7.2.

[0058] The average particle size of the manufactured sand is 0.55 mm; the average particle size of the basalt crushed stone is 7.5 mm.

[0059] The freeze-thaw stabilized composition is a combination of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer, and zirconium borate in a mass ratio of 6:2.5:1.5.

[0060] The specific surface area of ​​the mercapto-modified clinoptilolite was 420 m² / g, and it was sourced from Zhejiang Yuda Chemical Co., Ltd., China.

[0061] Zinc acrylate-styrene copolymer S728 is from Dow Chemical Company, USA.

[0062] The average particle size of zirconium borate is 80 nm.

[0063] The water-reducing agent is a high-efficiency polycarboxylate water-reducing agent with a water reduction rate of 25%, sourced from Shenyang Xingzhenghe Chemical Co., Ltd., China.

[0064] The air-entraining agent is sodium α-olefin sulfonate; the rust inhibitor is calcium nitrite; and the regulator is hydroxyethyl cellulose.

[0065] The reinforcing agent is 20mm basalt fiber from Jiangxi Shuobang New Materials, China.

[0066] The toughening agent is styrene-butadiene rubber latex SN-307R, sourced from Wuhan Lanabai, China.

[0067] The antifreeze is ethylene glycol.

[0068] The composite additive is a composition of methyl heptafluorobutyl acrylate and epoxy siloxane copolymer in a mass ratio of 6.5:2.5.

[0069] Epoxysiloxane copolymer, Silquest™ A-187, is from Momentive, USA.

[0070] A method for preparing the above-mentioned freeze-thaw resistant high-strength brick specifically includes the following steps: S1: After drying the gel material, add it to a high-speed mixer, and then add the remaining raw materials in sequence and mix at a high speed of 600 rpm for 15 min; S2: After mixing, pour it into a mold and let it stand at room temperature for 12 h, then cure it with steam at 50℃ / 95%RH for 24 h, and then cure it at a medium temperature of 75℃ for 6 h; S3: Finally, cure it in a curing chamber under standard curing conditions for 28 days to obtain the brick.

[0071] Example 2: This example differs from Example 1 only in the following aspects: A freeze-thaw resistant high-strength brick, by weight, comprises at least the following raw materials: 120 parts of gel material, 180 parts of aggregate system, 10 parts of freeze-thaw stabilized composition, 1.1 parts of water-reducing agent, 0.3 parts of air-entraining agent, 0.8 parts of rust inhibitor, 0.6 parts of regulator, 40 parts of water, 2.1 parts of reinforcing agent, 5.5 parts of toughening agent, 3.2 parts of antifreeze agent, and 6.5 parts of composite additive.

[0072] All other implementation schemes are the same.

[0073] Example 3: This example differs from Example 1 only in the following aspects: A freeze-thaw resistant high-strength brick, by weight, comprises at least the following raw materials: 100 parts of gel material, 190 parts of aggregate system, 17.5 parts of freeze-thaw stabilized composition, 1.1 parts of water-reducing agent, 0.3 parts of air-entraining agent, 0.8 parts of rust inhibitor, 0.6 parts of regulator, 40 parts of water, 2.1 parts of reinforcing agent, 5.5 parts of toughening agent, 3.2 parts of antifreeze agent, and 10.5 parts of composite additive.

[0074] All other implementation schemes are the same.

[0075] Comparative Example 2

[0076] The only difference between this comparative example and Example 1 is as follows: A freeze-thaw resistant high-strength brick, by weight, comprises at least the following raw materials: 111 parts of gel material, 182 parts of aggregate system, 14.8 parts of freeze-thaw stabilized composition, 1.1 parts of water-reducing agent, 0.3 parts of air-entraining agent, 0.8 parts of rust inhibitor, 0.6 parts of regulator, 40 parts of water, 2.1 parts of reinforcing agent, 5.5 parts of toughening agent, 3.2 parts of antifreeze agent, and 3 parts of composite additive.

[0077] All other implementation schemes are the same.

[0078] Comparative Example 3

[0079] The only difference between this comparative example and Example 1 is that the freeze-thaw stabilized composition is a combination of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate in a mass ratio of 8:1:0.5.

[0080] All other implementation schemes are the same.

[0081] Comparative Example 4

[0082] The only difference between this comparative example and Example 1 is that the freeze-thaw stabilized composition is a combination of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate in a mass ratio of 2:4:3.

[0083] All other implementation schemes are the same.

[0084] Comparative Example 5

[0085] The only difference between this comparative example and Example 1 is that the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxy siloxane copolymer in a mass ratio of 8:1.

[0086] All other implementation schemes are the same.

[0087] Comparative Example 6

[0088] The only difference between this comparative example and Example 1 is that the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxy siloxane copolymer in a mass ratio of 1:3.

[0089] All other implementation schemes are the same.

[0090] Performance testing

[0091] 1. Compressive strength: Refer to standard GB / T 17671-1999, and the result is the average of 10 tests, which is recorded in Table 1.

[0092] 2. Freeze-thaw resistance: Refer to standard ASTM C666. Freezing stage: -15℃ for 4 hours, thawing stage: 20℃ for 2 hours, 50 cycles. The compressive strength loss rate and mass loss rate are taken, and the average of 10 tests is recorded in Table 1.

[0093] 3. Salt freeze resistance: Refer to standard T0583-2020. Freezing stage: -20℃ for 4 hours. Melting stage: 20℃ for 4 hours. Number of cycles: 50. Take the mass of peeling material per unit area. The result is the average of 10 tests and is recorded in Table 1.

[0094] Table 1 Performance Test Results

[0095]

[0096] Based on the final performance test results of the examples and comparative examples, Comparative Example 2 did not use an appropriate amount of composite additives in combination with the freeze-thaw stabilized composition, which led to a significant deviation in its performance in the overall brick material system, and ultimately affected its actual effect. Its performance was significantly lower than that of Examples 1-3.

[0097] Comparative Examples 3 to 6, however, did not use the appropriate raw material blending ratios specified in this application, resulting in a significant decrease in their respective effects in the gel material, reduced efficiency of their mutual interaction, and consequently, lower performance test results.

Claims

1. A freeze-thaw resistant high-strength brick, characterized in that: By weight, the raw materials include: 90-130 parts of gel material, 160-200 parts of aggregate system, 8-20 parts of freeze-thaw stabilized composition, 0.8-1.6 parts of water-reducing agent, 0.1-0.5 parts of air-entraining agent, 0.5-1.5 parts of rust inhibitor, 0.3-1 part of regulator, 30-60 parts of water, 0.3-3 parts of reinforcing agent, 3-10 parts of toughening agent, 2-5 parts of antifreeze agent, and 3-12 parts of composite additive; The gel material is a composition of P·II 52.5 silicate cement and P 42.5 sulfoaluminate cement in a mass ratio of (6~9):(1~4). The freeze-thaw stabilized composition is a combination of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer, and zirconium borate, in a mass ratio of (5~6.5):(2~3):(1~2). The mass ratio of the gel material, aggregate system and freeze-thaw stabilized composition is (100~120):(170~190):(10~18). The mass ratio of the gel material to the composite additive is (100~120):(6~11). The composite additive is a composition of methyl heptafluorobutyl acrylate and epoxy siloxane copolymer in a mass ratio of (5~8):(1~3).

2. The freeze-thaw resistant high-strength brick according to claim 1, characterized in that: The aggregate system is a composition of manufactured sand and basalt crushed stone in a mass ratio of (10~14):(6~9).

3. The freeze-thaw resistant high-strength brick according to claim 2, characterized in that: The average particle size of the manufactured sand is 0.15~2.36 mm.

4. The freeze-thaw resistant high-strength brick according to claim 3, characterized in that: The average particle size of the basalt gravel is 5-15 mm.

5. The freeze-thaw resistant high-strength brick according to claim 4, characterized in that: The specific surface area of ​​the mercapto-modified clinoptilolite is 400~600m² / g; the average particle size of the zirconium borate is 60~100nm.

6. A method for preparing freeze-thaw resistant high-strength bricks according to any one of claims 1 to 5, characterized in that: S1: After drying the gel material, add it to a high-speed mixer, then add the remaining raw materials in sequence and mix at a high speed of 500~600rpm for 10~20min; S2: After mixing, pour it into a mold and let it stand at room temperature for 10~12h, then cure it with steam at 50℃ / 95%RH for 22~24h, and then cure it at a medium temperature of 70~75℃ for 6~8h; S3: Finally, cure it in a curing chamber under standard curing conditions for 28 days to obtain the final product.

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