A staged strength adaptive concrete reinforcing agent and its preparation method and application

Abstract

The present invention relates to a staged strength self-adaptive concrete reinforcing agent, which comprises the following raw materials by mass percentage: 20% to 30% of a calcium-based slow hydration reaction agent, 5% to 10% of a calcium sulfate-based substance, 3% to 7% of an acrylic ester organic matter, 5% to 10% of a soluble phosphate, 2% to 5% of an aluminum-based multifunctional modified material, 1% to 3% of a water reducer, and 45% to 55% of water. The staged strength self-adaptive concrete reinforcing agent of the present invention can be applied to concrete to achieve adjustable concrete fluidity and strength, automatically and accurately adjust the hydration reaction rate, ensure stable strength, and improve construction efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a staged strength self-adaptive concrete reinforcing agent and a preparation method and application thereof. Background Art

[0002] In the field of construction engineering, concrete is widely used, but it also faces many challenges. When pouring large volumes of concrete, a large amount of heat will be generated inside due to the cement hydration reaction, and it is difficult for traditional concrete to effectively control the hydration reaction rate. If the early hydration reaction rate is too fast, the concrete will harden quickly, which will produce a large amount of hydration heat accumulation, causing the internal temperature of the concrete to rise sharply, forming a large temperature difference with the external environment, thereby causing temperature cracks, seriously affecting the integrity and durability of the structure. For example, in the pouring of dams in large-scale water conservancy projects, crack problems may cause dam leakage or even structural instability. If the early strength develops too slowly, under the action of the concrete's own weight and construction loads, deformation, collapse and other accidents are prone to occur.

[0003] Concrete construction is even more difficult in extreme temperature environments. In high temperature environments, such as summer construction in hot areas, the evaporation rate of water in ordinary concrete is significantly accelerated, and the hydration reaction of cement particles is extremely violent, which causes the slump of concrete to decrease rapidly and the fluidity to deteriorate, making it unable to meet the construction process requirements. At the same time, high temperature will also shorten the setting time of concrete, develop early strength too quickly, increase internal stress, and increase the risk of cracks. In low temperature environments, such as winter construction in cold areas or projects in high-altitude cold areas, the cement hydration reaction becomes extremely slow, the setting time of concrete is greatly extended, and the early strength is difficult to improve quickly. This will not only delay the construction progress, but also expose the concrete to harsh environments for a long time in an unhardened state, making it extremely susceptible to frost damage, which seriously weakens the later strength and overall performance of the concrete.

[0004] Although self-compacting concrete has the advantage of high fluidity, it is extremely sensitive to changes in ambient temperature. At high temperatures, its high fluidity is difficult to maintain and its workability drops sharply; at low temperatures, its viscosity increases and its fluidity is insufficient, making it impossible to ensure smooth construction. In addition, traditional self-compacting concrete has obvious deficiencies in strength control and cannot effectively adjust strength development according to the construction stage and environmental conditions. In the early stages of construction, it is impossible to accurately control the cement hydration reaction rate, which can easily lead to premature or slow strength growth, resulting in cracks in the concrete during the hardening process or inability to withstand construction loads. The later strength growth is unstable, and it is difficult to meet the durability requirements of the structure for long-term use.

[0005] As the world's attention to environmental protection and sustainable development continues to increase, the concrete industry is also facing dual pressures of resources and the environment. Traditional concrete production relies on a large amount of natural resources, and the production and use of some admixtures may have adverse effects on the environment. Therefore, it is particularly urgent to develop a concrete technology that can automatically adjust the cement hydration reaction rate, adapt to different temperature environments, improve construction efficiency, and be environmentally friendly and sustainable. This is also the key to promoting high-quality development of the construction industry. Summary of the invention

[0006] In order to solve the above-mentioned problems of the prior art, the present invention provides a staged strength adaptive concrete enhancer, which selects calcium-based slow hydration reaction agents and calcium sulfate-based substances as key components, combines acrylic ester organic matter, soluble phosphates, aluminum-based multifunctional modified materials, and water reducer components to achieve adjustable concrete fluidity and strength, automatically and accurately adjust the hydration reaction rate, ensure stable strength, and improve construction efficiency.

[0007] The present invention provides the following technical solutions.

[0008] A staged strength self-adaptive concrete reinforcing agent comprises the following raw materials, measured by mass percentage: 20% to 30% of a calcium-based slow hydration reaction agent, 5% to 10% of a calcium sulfate-based substance, 3% to 7% of an acrylic ester organic matter, 5% to 10% of a soluble phosphate, 2% to 5% of an aluminum-based multifunctional modified material, 1% to 3% of a water reducing agent, and 45% to 55% of water.

[0009] In one of the embodiments, the staged strength adaptive concrete enhancer includes the following raw materials, measured in mass percentage: 22% to 30% calcium-based slow hydration reaction agent, 5% to 8% calcium sulfate-based substances, 4% to 6% acrylic ester organic matter, 7% to 10% soluble phosphate, 3% to 4% aluminum-based multifunctional modified material, 2% to 3% water reducer, and 48% to 49% water.

[0010] In the present invention, calcium-based slow hydration reaction agent and calcium sulfate-based substances are key components that can effectively regulate the hydration reaction rate of cement. The calcium-based slow hydration reaction agent slows down the reaction speed in the early stage of hydration through its special chemical structure, avoiding the internal stress concentration and crack generation caused by excessive early strength. Calcium sulfate-based substances participate in the reaction at different stages, providing continuous support for the stable development of strength. When pouring large volumes of concrete, this combination can effectively cope with the release of hydration heat, so that the internal temperature of the concrete rises evenly, reducing the risk of temperature cracks. For example, in the construction of large bridge foundations, this solution can ensure that the strength of concrete is steadily improved from the initial coagulation to the hardening stage during the long pouring process, effectively resisting the interference of external loads and environmental factors, and greatly enhancing the stability and durability of the structure.

[0011] In one embodiment, the calcium-based slow hydration agent is tricalcium aluminum silicate.

[0012] Tricalcium aluminum silicate can form a protective film on the surface of cement particles in the early stage of concrete, preventing water molecules from quickly contacting the main components of cement (such as tricalcium silicate and tricalcium aluminate), thereby effectively slowing down the early hydration rate of concrete. This delaying effect is very important to prevent concrete from hardening too quickly in the early stage of pouring, especially in large-volume concrete construction, to prevent temperature cracks caused by the concentrated release of hydration heat. At the same time, tricalcium aluminum silicate will continue to participate in the reaction during the hardening of concrete. Over time, it will gradually release aluminum ions and calcium ions, react with calcium hydroxide to generate more hydrated calcium aluminate, further fill the pore structure inside the concrete, and make the microstructure of the concrete more compact. This progressive reaction process helps the steady growth of concrete strength, avoids the situation where the early strength is too high and the later strength is stagnant, and ensures that the concrete has good strength performance in different construction stages and use stages.

[0013] It can be understood that, in the present invention, calcium sulfate-based substances refer to various substances containing calcium sulfate.

[0014] In one embodiment, the calcium sulfate-based material is selected from one or more of gypsum, calcium sulfate ore and fiber-reinforced calcium sulfate board.

[0015] In a preferred embodiment, the calcium sulfate-based substance is gypsum.

[0016] In the early stage of cement hydration, gypsum can react with tricalcium aluminate to form calcium aluminate, which covers its surface and delays initial setting, thus buying time for concrete construction; it continues to participate in the reaction in the later stage, compensating for shrinkage, reducing cracks, maintaining structural integrity, and improving strength and durability. At the same time, gypsum can enhance the fluidity of concrete, making cement particles evenly dispersed, like a lubricant, helping to fill complex spaces in self-compacting concrete, improving workability stability, and reducing slump loss caused by environmental factors. More importantly, gypsum and calcium-based slow hydration reaction agents work together to control the hydration rhythm and ensure stable strength. They work with admixtures such as water reducers to ensure workability and strength while reducing water, and can be combined with other functional admixtures as needed to flexibly adjust concrete performance.

[0017] In one embodiment, the acrylic ester organic compound is selected from one or more of hydroxy acrylate, epoxy acrylate and amino acrylate.

[0018] In a preferred embodiment, the acrylate organic substance is hydroxy acrylate. More specifically, the acrylate organic substance is 2-hydroxyethyl methacrylate.

[0019] Hydroxyacrylates can effectively improve the workability and fluidity of concrete. With their excellent dispersing properties, they can reduce cement particle agglomeration, enhance fluidity, maintain stable workability, and reduce slump loss. Their active hydroxyl functional groups can enhance adhesion and toughness, react with cement hydration products and aggregates to form chemical bonds, and improve bonding strength. Their network structure can absorb and disperse stress and reduce cracks. In terms of strength development, they participate in hydration reactions to form dense compounds, and can also synergize with other components to improve strength. In addition, hydroxyacrylates have environmental advantages, can reduce resource consumption, and are synthesized using industrial waste. They can reduce life cycle costs due to improved durability, and have significant comprehensive benefits.

[0020] In one embodiment, the soluble phosphate is selected from one or more of sodium hydrogen phosphate, disodium hydrogen phosphate and ammonium hydrogen phosphate.

[0021] In a preferred embodiment, the soluble phosphate is sodium hydrogen phosphate.

[0022] Sodium hydrogen phosphate can effectively regulate the cement hydration process. In the initial stage, it plays a retarding role by adsorbing on the surface of cement particles. It can prevent slump loss and cracks during high temperature or large-volume concrete construction. In the later stage, it participates in the reaction to promote stable strength growth and avoid imbalance in strength development.

[0023] It can be understood that, in the present invention, the aluminum-based multifunctional modified material refers to aluminates, aluminum compounds and their composite modifications.

[0024] In one embodiment, the aluminum-based multifunctional modified material is selected from one or more of sodium aluminate and calcium aluminate.

[0025] In a preferred embodiment, the aluminum-based multifunctional modified material is sodium aluminate.

[0026] Sodium aluminate can accelerate the cement hydration reaction, especially in the early stage, it can promote the rapid hydration of tricalcium aluminate and quickly generate products such as ettringite, effectively improving the early strength of concrete and meeting the needs of rapid construction. At the same time, it can work with other substances to optimize the microstructure of concrete, fill pores, enhance density, improve impermeability and durability, and reduce the intrusion of external erosion media.

[0027] In one embodiment, the water reducing agent is selected from polycarboxylate superplasticizer and lignin sulfonate water reducing agent.

[0028] In a preferred embodiment, the water reducing agent is a polycarboxylate superplasticizer.

[0029] The present invention also provides a method for preparing the above-mentioned staged strength self-adaptive concrete reinforcing agent, comprising the following steps:

[0030] The calcium-based slow hydration reaction agent, the calcium sulfate-based substance, the acrylic ester organic matter, the soluble phosphate, the aluminum-based multifunctional modified material, the water reducing agent and water are mixed according to the mass fraction.

[0031] The present invention also provides a use of the above-mentioned staged strength self-adaptive concrete reinforcing agent in preparing concrete.

[0032] The present invention also provides concrete, the components of which include cementitious materials, aggregates, temperature-responsive admixtures, the above-mentioned staged strength self-adaptive concrete reinforcing agent, and water.

[0033] In one embodiment, the temperature-responsive admixture includes the following raw materials, measured in mass percentage: 30% to 50% temperature-sensitive polymer material, 2% to 5% cross-linking agent, 3% to 5% water-soluble water reducer, 1% to 3% plasticizer, and 40% to 60% water.

[0034] In one embodiment, the temperature sensitive polymer material is selected from one or more of polyvinyl alcohol and sodium polyacrylate.

[0035] In one embodiment, the temperature-responsive fluid concrete admixture includes the following raw materials, measured in mass percentage: 34% to 46% of temperature-sensitive polymer material, 3% to 5% of cross-linking agent, 3% to 5% of water-soluble water reducer, 2% to 3% of plasticizer, and 44% to 55% of water.

[0036] In one embodiment, the temperature sensitive polymer material is a mixture of polyvinyl alcohol and sodium polyacrylate.

[0037] In one embodiment, the mass ratio of the polyvinyl alcohol to the sodium polyacrylate is (1.5-2):1.

[0038] It can be understood that in the present invention, the mass ratio of the polyvinyl alcohol to the sodium polyacrylate includes but is not limited to 1.5:1, 1.56:1, 1.6:1, 1.67:1, 1.7:1, 1.8:1, 1.83:1, 1.9:1, and 2:1.

[0039] In one embodiment, the cross-linking agent is selected from one or more of N,N'-methylenebisacrylamide, 1,4-benzenediacrylamide and N,N'-bis(acryloyl)cystamine.

[0040] In a preferred embodiment, the cross-linking agent is N,N'-methylenebisacrylamide.

[0041] In one embodiment, the water-soluble water reducing agent is a polycarboxylate water reducing agent.

[0042] In one embodiment, the polycarboxylate water reducer is selected from one or more of TPEG water reducer, HPEG water reducer and APEG water reducer.

[0043] In one embodiment, the plasticizer is selected from one or more of glycerol and polyvinyl alcohol ether.

[0044] The beneficial effects of the present invention are embodied in that:

[0045] The present invention can effectively adjust the hydration reaction rate of cement by screening out calcium-based slow hydration reaction agent and calcium sulfate-based substances as key components. The calcium-based slow hydration reaction agent slows down the reaction speed in the early stage of hydration through its special chemical structure, avoiding the internal stress concentration and crack generation caused by the excessive early strength. The calcium sulfate-based substances participate in the reaction at different stages, providing continuous support for the stable development of strength. The two work together to allow concrete to effectively respond to the release of hydration heat during large-volume pouring and extreme temperature construction, automatically and accurately adjust the hydration reaction rate, and ensure that the concrete is steadily improved in strength from the initial coagulation to the hardening stage during a long pouring process, effectively resisting the interference of external loads and environmental factors, and greatly enhancing the stability and durability of the structure. At the same time, acrylic organic matter is matched with a water reducer to make the concrete fluidity and strength adjustable, without the need for additional vibration, reducing noise and safety risks, and improving construction efficiency.

[0046] Furthermore, most of the components are made of industrial waste and natural fiber materials, which reduces dependence on natural resources and reflects environmental protection characteristics. Application to concrete can not only achieve efficient construction, but also reduce the impact on the environment. In long-term use, due to its good durability and corrosion resistance, it reduces maintenance costs and achieves the organic unity of convenient construction, environmental protection and multi-function. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available products.

[0049] Embodiment 1:

[0050] A stage-by-stage strength adaptive concrete reinforcing agent applicable to a standard construction stage (25°C) is prepared by mixing the following raw materials in percentage by mass: 25% of a calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 7% of a calcium sulfate-based substance (gypsum), 5% of an acrylic ester organic matter (2-hydroxyethyl methacrylate), 8% of a soluble phosphate (sodium hydrogen phosphate), 4% of an aluminum-based multifunctional modified material (sodium aluminate), 2% of a water reducer (polycarboxylate superplasticizer), and 49% of water.

[0051] Embodiment 2:

[0052] A stage-by-stage strength adaptive concrete reinforcing agent that can be used in cold construction stages (below 5°C) is prepared by mixing the following raw materials in percentage by mass: 30% of a calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 5% of a calcium sulfate-based substance (gypsum), 4% of an acrylic ester organic matter (2-hydroxyethyl methylacrylate), 7% of a soluble phosphate (sodium hydrogen phosphate), 3% of an aluminum-based multifunctional modified material (sodium aluminate), 2% of a water reducer (polycarboxylate superplasticizer), and 49% of water.

[0053] Embodiment 3:

[0054] A stage-by-stage strength adaptive concrete reinforcing agent that can be used in high-temperature construction stages (above 30° C.) is prepared by mixing the following raw materials in percentage by mass: 22% of a calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 8% of a calcium sulfate-based substance (gypsum), 6% of an acrylic ester organic matter (2-hydroxyethyl methylacrylate), 10% of a soluble phosphate (sodium hydrogen phosphate), 3% of an aluminum-based multifunctional modified material (sodium aluminate), 3% of a water reducer (polycarboxylate superplasticizer), and 48% of water.

[0055] Embodiment 4:

[0056] Other conditions were the same as those in Example 1, except that the type of raw material was changed: 25% of calcium-based slow hydration agent (calcium fluoroaluminate).

[0057] Embodiment 5:

[0058] The other conditions were the same as those in Example 2, except that the type of raw material was changed: 5% of calcium sulfate-based material (calcium sulfate ore).

[0059] Embodiment 6:

[0060] Other conditions were the same as those in Example 3, except that the type of raw material was changed: 6% of acrylic acid ester organic matter (methyl methacrylate).

[0061] Comparative Example 1:

[0062] A reinforcing agent, other conditions are consistent with Example 1, only the calcium sulfate-based substances are deleted: 32% of calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 5% of acrylic ester organic matter (2-hydroxyethyl methacrylate), 8% of soluble phosphate (sodium hydrogen phosphate), 4% of aluminum-based multifunctional modified material (sodium aluminate), 2% of water reducer (polycarboxylate superplasticizer), and 49% of water.

[0063] Comparative Example 2:

[0064] A reinforcing agent, other conditions are consistent with Example 2, only the acrylic organic matter is deleted: calcium-based slow hydration reaction agent (tricalcium aluminum silicate) 34%, calcium sulfate-based substance (gypsum) 5%, soluble phosphate (sodium hydrogen phosphate) 7%, aluminum-based multifunctional modified material (sodium aluminate) 3%, water reducer (polycarboxylate superplasticizer) 2%, and water 49%.

[0065] Comparative Example 3:

[0066] A reinforcing agent, other conditions are consistent with Example 3, only the soluble phosphate is deleted: 32% of calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 8% of calcium sulfate-based substance (gypsum), 6% of acrylic ester organic matter (2-hydroxyethyl methacrylate), 3% of aluminum-based multifunctional modified material (sodium aluminate), 3% of water reducer (polycarboxylate superplasticizer), and 48% of water.

[0067] Comparative Example 4:

[0068] A reinforcing agent, other conditions are consistent with Example 3, only the aluminum-based multifunctional modifying material is deleted: 25% of a calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 8% of a calcium sulfate-based substance (gypsum), 6% of an acrylic ester organic matter (2-hydroxyethyl methacrylate), 10% of a soluble phosphate (sodium hydrogen phosphate), 3% of a water reducing agent (polycarboxylate superplasticizer), and 48% of water.

[0069] Comparative Example 5

[0070] A reinforcing agent, other conditions are consistent with Example 3, and the mass fractions of raw materials are changed: 35% of calcium-based slow hydration reaction agent (tricalcium aluminum silicate), 4% of calcium sulfate-based substance (gypsum), 8% of acrylic ester organic matter (2-hydroxyethyl methacrylate), 12% of soluble phosphate (sodium hydrogen phosphate), 1% of aluminum-based multifunctional modified material (sodium aluminate), 5% of water reducer (polycarboxylate superplasticizer), and 35% of water.

[0071] Performance Testing

[0072] The same mass of the reinforcing agent prepared in Examples 1-6 and Comparative Examples 1-5 was taken and mixed with the same cement, sand, stone, and temperature-responsive admixture using the same steps to prepare concrete test blocks for performance testing.

[0073] The performance test results are shown in Table 1.

[0074] Table 1

[0075]

[0076]

[0077] In the description of the embodiments of the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0078] In the description of the embodiments of the present invention, it is to be understood that "-" and "~" represent the range between two values, and the range includes the endpoints. For example: "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0079] In the description of the embodiments of the present invention, the term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein generally indicates that the associated objects before and after are in an "or" relationship.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A staged strength adaptive concrete reinforcing agent, characterized in that: Calculated by mass percentage, the raw materials include: 20% to 30% of calcium-based slow hydration reaction agent, 5% to 10% of calcium sulfate-based substances, 3% to 7% of acrylic ester organic matter, 5% to 10% of soluble phosphate, 2% to 5% of aluminum-based multifunctional modified material, 1% to 3% of water reducer, and 45% to 55% of water.

2. The staged strength adaptive concrete reinforcing agent according to claim 1, characterized in that: The staged strength adaptive concrete reinforcing agent includes the following raw materials in percentage by mass: 22% to 30% of a calcium-based slow hydration reaction agent, 5% to 8% of a calcium sulfate-based substance, 4% to 6% of an acrylic ester organic matter, 7% to 10% of a soluble phosphate, 3% to 4% of an aluminum-based multifunctional modified material, 2% to 3% of a water reducer, and 48% to 49% of water.

3. The staged strength adaptive concrete reinforcing agent according to claim 1 or 2, characterized in that: The calcium-based slow hydration reaction agent is tricalcium aluminum silicate.

4. The staged strength adaptive concrete reinforcing agent according to claim 1 or 2, characterized in that: The calcium sulfate-based substance is gypsum.

5. The staged strength adaptive concrete reinforcing agent according to claim 1 or 2, characterized in that: The acrylic ester organic matter is selected from one or more of hydroxy acrylate, epoxy acrylate and amino acrylate.

6. The staged strength adaptive concrete reinforcing agent according to claim 1 or 2, characterized in that: The soluble phosphate is selected from one or more of sodium hydrogen phosphate, disodium hydrogen phosphate and ammonium hydrogen phosphate; and / or The aluminum-based multifunctional modified material is selected from one or more of sodium aluminate and calcium aluminate; and / or The water reducing agent is selected from polycarboxylate superplasticizer and lignin sulfonate water reducing agent.

7. The method for preparing the staged strength adaptive concrete reinforcing agent according to any one of claims 1 to 6, characterized in that: The steps include: The calcium-based slow hydration reaction agent, the calcium sulfate-based substance, the acrylic ester organic matter, the soluble phosphate, the aluminum-based multifunctional modified material, the water reducing agent and water are mixed according to the mass fraction.

8. Use of the staged strength self-adaptive concrete reinforcing agent according to any one of claims 1 to 6 in the preparation of concrete.

9. A concrete, characterized in that: The components of the concrete include cementitious materials, aggregates, temperature-responsive admixtures, the staged strength self-adaptive concrete reinforcing agent according to any one of claims 1 to 6, and water.

10. The concrete according to claim 9, characterized in that In terms of mass percentage, the temperature responsive admixture comprises the following raw materials: 30% to 50% of temperature sensitive polymer material, 2% to 5% of cross-linking agent, 3% to 5% of water-soluble water reducing agent, 1% to 3% of plasticizer, and 40% to 60% of water.

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