Freeze-thaw resistant high-strength brick and preparation method thereof

Abstract

The invention relates to the field of building materials, in particular to a freeze-thaw resistant high-strength brick and a preparation method thereof. The freeze-thaw resistant high-strength brick at least comprises the following raw materials in parts by mass: 90-130 parts of a gel material, 160-200 parts of an aggregate system, 8-20 parts of a freeze-thaw stable composition, 0.8-1.6 parts of a water reducing agent, 0.1-0.5 part of an air entraining agent, 0.5-1.5 parts of a corrosion inhibitor, 0.3-1 part of a conditioning agent and 30-60 parts of water. The freeze-thaw-resistant high-strength brick prepared in the invention not only can maintain excellent freeze-thaw resistance and compressive strength of the brick material, but also can further improve the stability and salt freezing corrosion resistance of the brick material as well as the durability and service life of the brick material in long-term use in harsh environment areas; therefore, excellent comprehensive performance is obtained to meet the requirements of the existing building materials on the brick.

Description

Technical Field

[0001] The present application relates to the field of building materials, and more specifically to a freeze-thaw resistant high-strength brick and a preparation method thereof. Background Art

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

[0003] Currently, many types of bricks are commercially available. Traditional concrete bricks, for example, are widely used due to their low cost and simple production process. However, they perform poorly in the face of frequent freeze-thaw cycles, prone to cracking or spalling, which severely impacts their service life. To enhance the freeze-thaw resistance of concrete bricks, researchers have experimented with adding various chemical additives, such as air inclusion formers and water-repellents, during the production process. While these additives can improve the material's freeze resistance to a certain extent, they can also have negative consequences, such as increasing production costs and affecting other physical properties (such as shrinkage). Polymer-modified cementitious composites, by combining organic polymers with cementitious materials, can significantly improve the material's toughness, crack resistance, and durability. These materials not only exhibit excellent freeze-thaw resistance but also provide high strength. However, the relatively poor stability and volatility of polymers limit their large-scale application. High-performance concrete bricks using special aggregates or admixtures, such as specific types of aggregates (such as lightweight aggregates) or the addition of mineral admixtures (such as silica fume and fly ash), can effectively improve the freeze-thaw resistance and mechanical properties of concrete. However, this method requires strict selection of raw materials and is relatively complex in production.

[0004] Therefore, although existing technologies have improved the freeze-thaw resistance and strength of building materials to a certain extent, there are still some shortcomings. Their problems are mainly reflected in the need to improve freeze-thaw resistance and its stability, the urgent need to improve salt freeze 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 better comprehensive performance has become a key topic studied by those skilled in the art. The applicant, through continuous research on this type of high-strength brick, proposes a freeze-thaw-resistant high-strength brick and a preparation method thereof in this application. The freeze-thaw-resistant high-strength brick prepared in this application can not only maintain excellent freeze-thaw resistance and compressive strength of the brick material, but also further improve the stability of the brick material, resistance to salt and frost corrosion, and durability and service life for long-term use in harsh environmental areas, thereby obtaining excellent comprehensive performance to meet the demand for this type of brick in existing building materials.

[0006] A freeze-thaw resistant high-strength brick comprises, by weight, at least 90-130 parts of a gel material, 160-200 parts of an aggregate system, 8-20 parts of a freeze-thaw stable composition, 0.8-1.6 parts of a water reducer, 0.1-0.5 parts of an air entraining agent, 0.5-1.5 parts of a rust inhibitor, 0.3-1 parts of a regulator, and 30-60 parts of water.

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

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

[0009] In a preferred embodiment, the gel material is a combination of Portland cement, P·II 52.5 Portland cement and P 42.5 sulphoaluminate cement.

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

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

[0012] In a preferred embodiment, the aggregate system is a combination of machine-made sand and basalt crushed stone.

[0013] In a preferred embodiment, the mass ratio of the machine-made sand to the basalt gravel is (10-14): (6-9).

[0014] In a preferred embodiment, the mass ratio of the machine-made sand to the basalt gravel is (11-12): (7-9).

[0015] In a preferred embodiment, the average particle size of the machine-made sand is 0.15-2.36 mm.

[0016] In a preferred embodiment, the average particle size of the machine-made sand is 0.15-2.36 mm.

[0017] In a preferred embodiment, the average particle size of the basalt gravel is 5 to 15 mm.

[0018] In a preferred embodiment, the average particle size of the basalt gravel is 7-10 mm.

[0019] In a preferred embodiment, the freeze-thaw stable composition is a composition of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate.

[0020] 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).

[0021] 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).

[0022] In a preferred embodiment, the specific surface area of ​​the mercapto-modified clinoptilolite is 400-600 m² / g.

[0023] In a preferred embodiment, the average particle size of the zirconium borate is 60-100 nm.

[0024] The freeze-thaw stable composition added in this application absorbs water molecules through microporous action to maintain liquid state at low temperatures, and then uses the mesopores as a directional buffer layer to absorb the ice crystal expansion stress; and the Zn²⁺ in the copolymer forms a ≡Si-O-Zn covalent bond with the cement hydration product CSH, constructing an ion 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 the 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 the thermal mismatch stress, and cooperating with the surface hydroxyl groups to form a ≡Si-O-Zr-B chemical bond with CSH, thereby greatly reducing the microcrack density after freeze-thaw, enhancing the melting resistance and overall stability.

[0025] In a preferred embodiment, the water reducer is at least one of a high-efficiency polycarboxylate water reducer or a naphthalene-based water reducer.

[0026] In a preferred embodiment, the water reducer is a high-efficiency polycarboxylate water reducer.

[0027] In a preferred embodiment, the air entraining agent is at least one of sodium α-olefin sulfonate, rosin resin triterpenoid saponin, polyethylene glycol oleate and sodium lauryl sulfate.

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

[0029] In a preferred embodiment, the air entraining agent is sodium α-olefin sulfonate.

[0030] In a preferred embodiment, the rust inhibitor is at least one of calcium nitrite, sodium benzoate, lithium nitrate and triethanolamine phosphate.

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

[0032] In a preferred embodiment, the rust inhibitor is calcium nitrite.

[0033] In a preferred embodiment, the regulator is at least one of hydroxyethyl cellulose, acrylamide copolymer, attapulgite clay colloid and hydrophobic polyacrylic acid.

[0034] In a preferred embodiment, the conditioning agent is hydroxyethyl cellulose or attapulgite clay colloid.

[0035] In a preferred embodiment, the regulator is hydroxyethyl cellulose.

[0036] In a preferred embodiment, the freeze-thaw resistant high-strength bricks further comprise, by weight, 0.3 to 3 parts of reinforcing agent, 3 to 10 parts of toughening agent, 2 to 5 parts of antifreeze agent and 3 to 12 parts of composite additives.

[0037] In a preferred embodiment, the mass ratio of the gel material to the composite additive is (100-120): (6-11).

[0038] In a preferred embodiment, the mass ratio of the gel material to the composite additive is (100-110): (8-10).

[0039] In a preferred embodiment, the reinforcing agent is at least one of polypropylene fiber, glass fiber and basalt fiber.

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

[0041] In a preferred embodiment, the reinforcing agent is basalt fiber.

[0042] In a preferred embodiment, the toughening agent is at least one of styrene-butadiene rubber emulsion, epoxy resin emulsion, ethylene-vinyl acetate copolymer emulsion and polyurethane emulsion.

[0043] In a preferred embodiment, the toughening agent is styrene-butadiene rubber emulsion or ethylene-vinyl acetate copolymer emulsion.

[0044] In a preferred embodiment, the toughening agent is styrene-butadiene rubber latex.

[0045] In a preferred embodiment, the antifreeze agent is at least one of ethylene glycol, triethanolamine and propylene carbonate.

[0046] In a preferred embodiment, the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxysilicone copolymer.

[0047] In a preferred embodiment, the mass ratio of the methyl heptafluorobutyl acrylate to the epoxysiloxane copolymer is (5-8):(1-3).

[0048] In a preferred embodiment, the mass ratio of the methyl heptafluorobutyl acrylate to the epoxysiloxane copolymer is (6-7.5):(1.5-2.5).

[0049] In this application, the freeze-thaw stable composition and the composite additives are used to effectively regulate the water-salt phase change behavior of the brick system. While adsorbing ions, a multi-level protection mechanism is constructed in the material system, successfully achieving the unity of high mechanical strength and extreme environmental durability, and jointly blocking the penetration path of water and salt ions.

[0050] A preparation method of the above-mentioned freeze-thaw resistant high-strength brick specifically includes the following steps: S1: S1: Dry the gel material and add it to a high-speed mixer, then add the remaining raw materials in sequence and mix at a high speed of 500-600 rpm for 10-20 minutes; S2: After mixing is completed, add it to the mold and let it stand at room temperature for 10-12 hours, then steam cure at 50℃ / 95%RH for 22-24 hours, and solidify at a medium temperature of 70-75℃ for 6-8 hours; S3: Finally, cure it in a curing box under standard curing conditions until 28 days.

[0051] This application has practical significance and beneficial effects: 1. The freeze-thaw-resistant high-strength bricks prepared in this application can not only maintain excellent freeze-thaw resistance and compressive strength of the bricks, but also further improve the stability of the bricks, resistance to salt and frost corrosion, and durability and service life for long-term use in harsh environmental areas, thereby obtaining excellent comprehensive performance to meet the demand for this type of bricks in existing building materials.

[0052] 2. The freeze-thaw stable composition added in this application absorbs water molecules through microporous action to maintain liquid state at low temperatures, and then uses the mesopores as a directional buffer layer to absorb ice crystal expansion stress; and the Zn²⁺ in the copolymer forms a ≡Si-O-Zn covalent bond with the cement hydration product CSH, constructing an ion 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 the 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 the thermal mismatch stress, and cooperating with the surface hydroxyl groups and the ≡Si-O-Zr-B chemical bonds generated by CSH, thereby greatly reducing the microcrack density after freeze-thaw, enhancing the melting resistance and overall stability.

[0053] 3. In this application, the freeze-thaw stable composition and the composite additives are used to effectively regulate the water-salt phase change behavior of the brick system. While adsorbing ions, a multi-level protection mechanism is constructed in the material system, successfully achieving the unity of high mechanical strength and durability in extreme environments, and jointly blocking the penetration path of water and salt ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 and Figure 2 This is a finished picture of the freeze-thaw resistant high-strength bricks produced in the examples of this application. DETAILED DESCRIPTION

[0055] Example 1: A freeze-thaw resistant high-strength brick, the raw materials of which include at least 105 parts of gel material, 182 parts of aggregate system, 14.8 parts of freeze-thaw stable composition, 1.1 parts of water reducer, 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 8.8 parts of composite additives, calculated by mass.

[0056] The gel material is a composition of Portland cement, P·II 52.5 Portland cement and P 42.5 sulphoaluminate cement in a mass ratio of 8:2.5.

[0057] The aggregate system is a combination of machine-made sand and basalt crushed stone with a mass ratio of 11:7.2.

[0058] The average particle size of machine-made sand is 0.55 mm; the average particle size of basalt gravel is 7.5 mm.

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

[0060] The mercapto-modified clinoptilolite has a specific surface area of ​​420 m² / g and is sourced from Zhejiang Yuda Chemical, China.

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

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

[0063] The water reducer is a high-efficiency polycarboxylate water reducer with a water reduction rate of 25%, which comes from Shenyang Xingzhenghe Chemical, 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 reinforcement is 20mm basalt fiber from Shuobang New Materials in Jiangxi, China.

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

[0067] The antifreeze is ethylene glycol.

[0068] The composite additive is a composition of methyl heptafluorobutyl acrylate and epoxysiloxane copolymer, with a mass ratio of 6.5:2.5.

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

[0070] A preparation method of the above-mentioned freeze-thaw resistant high-strength brick specifically includes the following steps: S1: 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 minutes; S2: After mixing is completed, add it to the mold and let it stand at room temperature for 12 hours, then steam cure at 50℃ / 95%RH for 24 hours, and solidify at a medium temperature of 75℃ for 6 hours; S3: Finally, cure it in a curing box under standard curing conditions until 28 days.

[0071] Example 2: This example differs from Example 1 only in the following: a freeze-thaw resistant high-strength brick, whose raw materials include, by mass, at least: 120 parts of gel material, 180 parts of aggregate system, 10 parts of freeze-thaw stable composition, 1.1 parts of water reducer, 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 additives.

[0072] The other embodiments are the same.

[0073] Example 3: This example differs from Example 1 only in the following: a freeze-thaw resistant high-strength brick, whose raw materials include, by mass, at least: 100 parts of gel material, 190 parts of aggregate system, 17.5 parts of freeze-thaw stable composition, 1.1 parts of water reducer, 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 additives.

[0074] The other embodiments are the same.

[0075] Comparative Example 2 This comparative example differs from Example 1 only in the following: a freeze-thaw resistant high-strength brick, whose raw materials include, by mass, at least: 111 parts of gel material, 182 parts of aggregate system, 14.8 parts of freeze-thaw stable composition, 1.1 parts of water reducer, 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 additives.

[0076] The other embodiments are the same.

[0077] Comparative Example 3 The only difference between this comparative example and Example 1 is that the freeze-thaw stable composition is a composition of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate, with a mass ratio of 8:1:0.5.

[0078] The other embodiments are the same.

[0079] Comparative Example 4 The only difference between this comparative example and Example 1 is that the freeze-thaw stable composition is a composition of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate, with a mass ratio of 2:4:3.

[0080] The other embodiments are the same.

[0081] Comparative Example 5 The only difference between this comparative example and Example 1 is that the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxysilicone copolymer, with a mass ratio of 8:1.

[0082] The other embodiments are the same.

[0083] Comparative Example 6 The only difference between this comparative example and Example 1 is that the composite additive is a composition of methyl heptafluorobutyl acrylate and epoxysiloxane copolymer, with a mass ratio of 1:3.

[0084] The other embodiments are the same.

[0085] Performance Testing 1. Compressive strength: Refer to GB / T 17671-1999. The average of 10 tests is reported in Table 1.

[0086] 2. Freeze-thaw resistance: Refer to ASTM C666 standard, freezing stage: keep at -15℃ for 4 hours, melting stage: keep at 20℃ for 2 hours, cycle 50 times, take the compressive strength loss rate and mass loss rate, and take the average of 10 tests and record them in Table 1.

[0087] 3. Salt-freeze resistance: Refer to standard T0583-2020, freezing stage: maintain at -20℃ for 4 hours, melting stage: maintain at 20℃ for 4 hours, number of cycles: 50 times, take the mass of peeling per unit area, and take the average value of 10 tests and record it in Table 1.

[0088] Table 1 Performance test results

[0089] Judging from the final performance test results of the embodiments and comparative examples, Comparative Examples 1-2 did not use a suitable amount of composite additives in combination with the freeze-thaw stable composition, which led to a significant deviation in their performance effects in the overall brick material system, ultimately affecting their actual effects. The performance was significantly reduced compared to Examples 1-3.

[0090] However, since Comparative Examples 3 to 6 did not adopt the appropriate raw material compounding ratio specified in the present application, their corresponding effects in the gel material were significantly reduced, the efficiency of their mutual interaction was reduced, and lower performance test results were obtained.

Claims

1. A freeze-thaw resistant high-strength brick, characterized by: Calculated by mass, the raw materials include at least: 90-130 parts of gel material, 160-200 parts of aggregate system, 8-20 parts of freeze-thaw stable composition, 0.8-1.6 parts of water reducer, 0.1-0.5 parts of air entraining agent, 0.5-1.5 parts of rust inhibitor, 0.3-1 parts of regulator, and 30-60 parts of water; The gel material is a composition of Portland cement, P·II 52.5 Portland cement and P 42.5 sulphoaluminate cement in a mass ratio of (6-9):(1-4); The freeze-thaw stable composition is a composition of mercapto-modified clinoptilolite, zinc acrylate-styrene copolymer and zirconium borate, with a mass ratio of (5-6.5): (2-3): (1-2).

2. The freeze-thaw resistant high-strength brick according to claim 1, characterized in that: The mass ratio of the gel material, the aggregate system and the freeze-thaw stable composition is (100-120): (170-190): (10-18).

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

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

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

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

7. The freeze-thaw resistant high-strength brick according to claim 1, characterized in that: The freeze-thaw resistant high-strength bricks further comprise, by weight, 0.3 to 3 parts of reinforcing agent, 3 to 10 parts of toughening agent, 2 to 5 parts of antifreeze agent and 3 to 12 parts of composite additives.

8. The freeze-thaw resistant high-strength brick according to claim 7, characterized in that: The mass ratio of the gel material to the composite additive is (100-120): (6-11).

9. The freeze-thaw resistant high-strength brick according to claim 8, characterized in that: The composite additive is a composition of methyl heptafluorobutyl acrylate and epoxysiloxane copolymer, with a mass ratio of (5-8): (1-3).

10. A method for preparing freeze-thaw resistant high-strength bricks according to any one of claims 1 to 9, 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 high speed; S2: After mixing, add it to the mold and let it stand at room temperature, steam cure at 50℃ / 95%RH, and cure at medium temperature; S3: Finally, cure it in a curing box under standard curing conditions for 28 days.

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