Composite hydration heat inhibitor, preparation method and application thereof

Abstract

The application relates to a composite hydration heat inhibitor and a preparation method and application thereof. The composite hydration heat inhibitor comprises: a phase change material; a carrier material, which is loaded on the surface of the phase change material to form a shell and forms a core-shell structure material with the phase change material; and a chemical inhibitor, which is connected with the core-shell structure material modified by a surface modifier to form the composite hydration heat inhibitor; and the mass ratio of the phase change material to the chemical inhibitor in the composite hydration heat inhibitor is 3-5:1. The application solves the technical problem of how to provide a composite hydration heat inhibitor, increases the content of the phase change material in the composite hydration heat inhibitor, avoids direct contact of a large amount of the phase change material with concrete, reduces the use amount of the chemical inhibitor, and improves the durability of the mechanical strength of the concrete.

Description

Technical Field

[0001] This invention belongs to the field of concrete, and in particular relates to a composite heat of hydration inhibitor, its preparation method, and its application. Background Technology

[0002] Concrete temperature cracking is a major problem that must be addressed in the field of civil engineering. To suppress or even avoid concrete cracking, common technical means include laying cooling water pipes and adding external inhibitors that can regulate the heat of cement hydration.

[0003] A literature discloses a temperature-controlled phase change release hydration heat regulation material, its preparation method, and its application. The hydration heat regulation material has a core-shell structure, comprising a carrier loaded with cement hydration inhibitory material and a coating formed by phase change wax on the surface of the carrier. The phase change wax is the outer shell material. During use, it can effectively control the total amount of early heat release of concrete and control the cement hydration reaction rate, thereby reducing the maximum temperature rise inside the concrete and reducing the temperature difference between its inside and outside, so as to reduce the temperature shrinkage cracks of concrete and achieve the purpose of reducing the risk of concrete cracking.

[0004] However, the aforementioned temperature-controlled phase change release hydration heat regulation materials disclosed in the prior art use phase change materials as coatings, which involve a large amount of phase change materials directly contacting the concrete, absorbing a large amount of hydration heat, affecting the cementitious rate of the concrete, affecting the strength of the concrete, and more importantly, affecting the durability of the mechanical properties of the concrete; in addition, the use of a large amount of chemical inhibitors will also affect the durability of the mechanical properties of the concrete. Summary of the Invention

[0005] The main objective of this invention is to provide a composite heat of hydration inhibitor, its preparation method, and its application. The technical problem to be solved is how to provide a composite heat of hydration inhibitor that increases the content of phase change material in the composite heat of hydration inhibitor, avoids a large amount of phase change material from directly contacting concrete, reduces the amount of chemical inhibitor used, and improves the durability of concrete mechanical strength.

[0006] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A composite hydration heat inhibitor according to this invention comprises:

[0007] Phase change materials;

[0008] A carrier material is loaded onto the surface of the phase change material to form a shell, thus forming a core-shell structure material with the phase change material.

[0009] A chemical inhibitor, wherein the chemical inhibitor is connected to a core-shell structure material modified by a surface modifier to form a composite hydration heat inhibitor; the mass ratio of the phase change material to the chemical inhibitor in the composite hydration heat inhibitor is 3 to 5:1.

[0010] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0011] Preferably, in the aforementioned heat of hydration inhibitor, the content of each component, by mass percentage, is: 50-80% phase change material, 10-35% carrier material, and 5-15% chemical inhibitor.

[0012] Preferably, in the aforementioned hydration heat inhibitor, the phase change material is selected from at least one of paraffin, stearic acid, and fatty acid esters; and the carrier material is selected from at least one of nanoscale liposomes, expanded graphite, porous ceramic particles, and silica aerogel.

[0013] Preferably, in the aforementioned hydration heat inhibitor, the chemical inhibitor is composed of a slow-setting polycarboxylate superplasticizer and nanomaterials in a mass ratio of 3 to 5:1.

[0014] Preferably, in the aforementioned hydration heat inhibitor, the nanomaterial is selected from at least one of silica, titanium dioxide, clay, and hydroxyapatite.

[0015] Preferably, in the aforementioned hydration heat inhibitor, the surface modifier is a silane coupling agent and / or a titanate coupling agent.

[0016] Preferably, in the aforementioned heat of hydration inhibitor, the surface of the composite heat of hydration inhibitor is further coated with a film to form a coating body; the coating film is a polymer film or a metal oxide film; the leakage rate of the phase change material in the coating body is ≤2%, and the leakage rate is ≠0.

[0017] Preferably, in the aforementioned hydration heat inhibitor, the coating film thickness is 50–200 μm.

[0018] The objective of this invention and the technical problem it solves are further achieved by the following technical solution. A method for preparing a composite hydration heat inhibitor according to this invention includes the following steps:

[0019] Non-solid phase change materials are encapsulated and shaped using carrier materials to form core-shell structure materials;

[0020] The core-shell structure material is modified using a surface modifier;

[0021] A composite hydration heat inhibitor is formed by mixing surface-modified core-shell structured materials with chemical inhibitors.

[0022] The mass ratio of phase change material to chemical inhibitor in the composite hydration heat inhibitor is 3-5:1.

[0023] The objective of this invention and the technical problem it solves are also achieved by the following technical solution. According to the aforementioned solution of this invention, the composite heat of hydration inhibitor is applied in a method wherein the composite heat of hydration inhibitor is added at 3-5% of the total mass of cementitious materials in the concrete mixture.

[0024] By employing the above technical solution, the composite hydration heat inhibitor, its preparation method, and its application proposed in this invention have at least the following advantages:

[0025] This invention provides a composite hydration heat inhibitor, its preparation method, and its application. By loading a carrier material onto the surface of a phase change material to form a core-shell structure, and further adding a chemical inhibitor, a composite hydration heat inhibitor is formed. Under the action of hydration heat, the chemical inhibitor helps to activate the outer shell of the core-shell structure and assists in controlling the gradual dissolution of the carrier material's outer shell, thereby controlling the gradual release of the phase change material. This not only avoids a large amount of phase change material directly contacting the cementitious materials in concrete, but also effectively reduces the amount of chemical inhibitor used, thus avoiding affecting the hydration rate of the cementitious materials and ensuring the mechanical durability of the concrete.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a composite hydration heat inhibitor;

[0028] Figure 2 The graphs show the internal temperature rise curves of concrete during the preparation of concrete in groups A, B, and C in Example 1. Detailed Implementation

[0029] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes a composite hydration heat inhibitor, its preparation method, and its application according to the present invention. Its specific implementation methods, structure, features, and effects are detailed below.

[0030] This invention provides a composite hydration heat inhibitor, comprising:

[0031] Phase change materials;

[0032] The carrier material is loaded onto the surface of the phase change material to form a shell, thus forming a core-shell structure with the phase change material, as shown in the attached figure. Figure 1 As shown, 1 is the phase change material, 2 is the carrier material shell, and 3 is the chemical inhibitor.

[0033] A chemical inhibitor, wherein the chemical inhibitor is connected to a core-shell structure material modified by a surface modifier to form a composite hydration heat inhibitor; the mass ratio of the phase change material to the chemical inhibitor in the composite hydration heat inhibitor is 3 to 5:1.

[0034] In the aforementioned scheme, the phase change material (PCM) absorbs heat during the concrete hydration process using its phase change heat, thereby reducing the rate of temperature rise within the concrete. To better control the heat of hydration of the PCM, some embodiments preferably use a PCM whose latent heat release peak matches the peak heat release during cement hydration of the cementitious material. Since the peak heat release during cement hydration of the cementitious material is generally in the range of 12–48 hours, the latent heat release peak of the PCM in this invention is also in the range of 12–48 hours. More preferably, the PCM is an organic PCM. In other embodiments, the PCM used is at least one of paraffin wax, stearic acid, and fatty acid esters. Under these conditions, the latent heat release peak of the PCM matches the peak heat release during cement hydration of the cementitious material better, which is more conducive to controlling the heat of hydration of the cementitious material.

[0035] In the aforementioned scheme, the carrier material is used to encapsulate the phase change material. The carrier material acts as a shell, forming a core-shell structure with the phase change material to prevent significant leakage of the phase change material and simultaneously improve its thermal stability. To ensure good compatibility between the carrier material and the phase change material, some embodiments preferably use at least one of nanoscale liposomes, expanded graphite (porosity ≥90%), porous ceramic particles, and silica aerogel as the carrier material.

[0036] In the aforementioned scheme, the chemical inhibitor is used to regulate the cement hydration rate, prolong the hydration induction period, and, under the action of hydration heat, helps to activate the outer shell of the core-shell structure material, causing the carrier shell to gradually dissolve, thereby controlling the gradual release of the phase change material. The chemical inhibitor of this invention is preferably matched with the phase change temperature of the phase change material and the porosity of the carrier material to ensure that the composite hydration heat inhibitor described in this invention can effectively function during the peak period of hydration heat release. In some embodiments, the chemical inhibitor is composed of a retarded polycarboxylate superplasticizer and nano-silica in a mass ratio of 3-5:1. Nano-silica can also refine the pore structure of concrete, improve the density of concrete, reduce the concentrated release of hydration heat, and help enhance the mechanical strength of concrete. Further preferably, in other embodiments, the nanomaterial is selected from at least one of silica, titanium dioxide, clay, and hydroxyapatite. Under these conditions, the concrete has good strength, and the materials are relatively more economical.

[0037] In order to enhance the tightness of the connection and interfacial compatibility between the chemical inhibitor and the carrier, thereby achieving a dual blockade of the phase change material and reducing the leakage and dispersion of the phase change material, some embodiments use silane coupling agents and / or titanate coupling agents as surface modifiers.

[0038] In order to better enable the phase change material, carrier material and chemical inhibitor to interact and synergize, in some embodiments, the content of each component, by mass percentage, is further preferred to be: 50-80% phase change material, 10-35% carrier material and 5-15% chemical inhibitor; in other embodiments, the content of each component is preferred to be: 50-70% phase change material, 15-35% carrier material and 10-15% chemical inhibitor. The aforementioned scheme strictly controls the mass percentage of each component to ensure that its retarding effect and refining effect are fully exerted, while avoiding adverse effects on the mechanical properties of concrete.

[0039] In order to improve the stability of the composite heat of hydration inhibitor described in the present invention, the surface of the composite heat of hydration inhibitor further includes a coating film to form a coating body. To enable the phase change material to absorb the heat released early in the concrete, the leakage rate of the phase change material in the coating body is ≤2%, and the leakage rate ≠ 0. Furthermore, to ensure the gradual release of the chemical inhibitor and phase change material in the composite heat of hydration inhibitor and to steadily control the accumulation of heat in the concrete, some embodiments preferably use a polymer film (e.g., polyvinyl alcohol film, polydopamine film), while other embodiments use a metal oxide film, such as titanium oxide film, alumina film. To better control the gradual release of the phase change material, in some embodiments, the thickness of the coating film is further preferably 50–200 μm.

[0040] This invention provides a composite heat of hydration inhibitor, which comprises a phase change material, a carrier material, and a chemical inhibitor that work synergistically. The presence of the chemical inhibitor facilitates the activation of the carrier-phase change material complex's performance, and it prolongs the cement hydration reaction efficiency and hydration induction period, thereby reducing the early temperature rise rate of concrete. This retarding effect complements the physical adsorption mechanism of the phase change material, forming a dual temperature control mechanism that effectively controls the release of heat of hydration at different stages. This composite heat of hydration inhibitor not only effectively controls the heat of hydration in concrete but also improves the mechanical properties and durability of concrete, demonstrating broader application prospects and higher technological content.

[0041] This invention also provides a method for preparing a composite hydration heat inhibitor, which includes the following steps:

[0042] Phase change material encapsulation: Non-solid phase change materials are encapsulated and shaped using a carrier material to form a core-shell structure. In some embodiments, paraffin wax is loaded into expanded graphite via vacuum impregnation, achieving encapsulation of the phase change material paraffin wax by the carrier material expanded graphite, forming a core-shell structure with a particle size of 1-3 mm. In other embodiments, the vacuum degree of the vacuum impregnation method is ≤0.1 MPa, and the impregnation time is ≥2 hours. In still other embodiments, nano-sized liposomes are used as the carrier material, with a particle size ≤100 nm. The liposomes are uniformly adsorbed onto molten paraffin wax (phase change material) by ultrasonic oscillation for 30 minutes, achieving encapsulation of the paraffin wax and forming a microcapsule-type core-shell structure. In still other embodiments, nano-sized liposomes are used as the carrier, and stearic acid is used as the phase change material, employing the aforementioned scheme to encapsulate stearic acid, forming a microcapsule-type core-shell structure.

[0043] Composite Process: The encapsulated phase change material, i.e., the core-shell structure material described in this invention, is modified using a surface modifier. In some embodiments, a silane coupling agent is added as a surface modifier. This not only facilitates the smooth integration of the core-shell structure material and the chemical inhibitor in subsequent processes but also helps to increase the tightness of the bond between the phase change material and the carrier material. The surface-modified core-shell structure material is mixed with the chemical inhibitor to form a composite hydration heat inhibitor. The mass ratio of the phase change material to the chemical inhibitor in the composite hydration heat inhibitor is 3–5:1. Strictly controlling this mass ratio not only better ensures the control of the hydration heat of concrete by the composite hydration heat inhibitor formed in this invention but also better achieves dual encapsulation of the phase change material by the carrier material and the chemical inhibitor, improving the thermal stability of the phase change material.

[0044] A further preferred embodiment of the aforementioned technical solution involves encapsulating a carrier onto the surface of a phase change material using at least two process technologies. The core-shell structure materials obtained from these multiple encapsulation processes are then mixed. The surface of the mixed core-shell structure material is then modified. Finally, the surface-modified mixed core-shell structure material is mixed with a chemical inhibitor, allowing the chemical inhibitor to adhere to the surface of the mixed core-shell structure material, thus achieving a dual containment of the phase change material. Some embodiments employ ultrasonic oscillation and vacuum impregnation methods to load the carrier material onto the surface of the phase change material, forming a core-shell structure material. These are then mixed to form a hybrid core-shell structure material. This approach facilitates a balance between leakage control and heat transfer efficiency. The resulting core-shell structure is tightly bonded to the porous load, exhibiting good stability. This is particularly beneficial for large-volume concrete requiring multi-layered temperature control mechanisms, as the mixing process can simultaneously meet both microscopic and macroscopic requirements.

[0045] In preferred embodiments, to further improve the stability of the composite heat of hydration inhibitor, a fluidized bed process is used to coat the composite heat of hydration inhibitor with a polymer film, such as a polyvinyl alcohol film or a polydopamine film, at 50–70°C. In further preferred embodiments, the coating thickness of the film is 50–200 μm. After coating, the leakage rate of the phase change material is ≤2%, and the leakage rate ≠ 0. Other embodiments use a metal oxide film with good tear resistance, strong thermal stability, and biodegradability, such as an alumina film or titanium dioxide film for the composite heat of hydration inhibitor, to improve the stability of the composite heat of hydration inhibitor.

[0046] The preparation process of the composite hydration heat inhibitor described in this invention is relatively simple, and it has significant advantages in terms of environmental friendliness.

[0047] The present invention also provides a method for applying the composite heat of hydration inhibitor described in the foregoing scheme. In some embodiments, the composite heat of hydration inhibitor is added at 3-5% of the total mass of cementitious materials in the concrete. Under this condition, the composite heat of hydration inhibitor described in the present invention can not only effectively control the temperature rise rate and temperature of the concrete, but also ensure that the prepared concrete has good mechanical strength and durability.

[0048] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0049] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0050] In the following embodiments of the present invention, the concrete composition used is as follows: by weight, it includes:

[0051] 395 parts cement, 45 parts fly ash, 45 parts mineral powder, 15 parts silica fume, 750 parts river sand, 1050 parts coarse aggregate, and 160 parts water.

[0052] The cement used is 42.5 low-heat silicate cement, the mineral powder is S95 grade mineral powder, the fly ash is grade 1 fly ash, and the silica fume is micro silica fume (specific surface area ≥ 15,000 m²). 2 / kg), the sand is medium sand with a fineness modulus of 2.6, and the coarse aggregate is crushed stone with a continuous gradation of 5-20mm.

[0053] The testing and calculation methods for the detection indicators involved in the following embodiments and comparative examples of the present invention are as follows:

[0054] The compressive strength of concrete shall be tested in accordance with GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0055] Concrete compressive strength retention rate: Taking the 28-day compressive strength of concrete without the addition of composite heat of hydration inhibitor as K1, and the 28-day compressive strength of concrete with the addition of composite heat of hydration inhibitor as K2, the concrete compressive strength retention rate = (K1 - K2) / K2 × 100%; the 28-day compressive strength retention rate of concrete without the addition of composite heat of hydration inhibitor is 100%.

[0056] The reduction in the peak value of the maximum hydration rate of concrete: taking the peak value of the maximum hydration rate of concrete without the addition of composite hydration heat inhibitor as α1, and the peak value of the maximum hydration rate of concrete with the addition of composite hydration inhibitor as α2, the reduction in the peak value of the maximum hydration rate of concrete with the addition of composite hydration inhibitor is (α1-α2) / α1×100%.

[0057] The initial phase change material leakage rate of the composite hydration heat material was tested using the weight loss method, with the specific steps as follows:

[0058] 1. Sample pretreatment:

[0059] The composite hydration heat inhibitor was placed in a 60℃ constant temperature chamber for 24 hours to simulate the high-temperature environment during the initial stage of concrete hydration. The initial mass (m0) was weighed, accurate to 0.1 mg.

[0060] 2. Test:

[0061] The temperature was raised to 10°C above the melting point of the phase change material to simulate the hydration temperature rise process of concrete. The remaining mass (m1) was weighed, and the initial leakage rate was calculated: Leakage rate = (m0-m1) / m0×100%.

[0062] Example 1

[0063] This embodiment provides a composite hydration heat inhibitor and its preparation method, as detailed below:

[0064] 1. Raw material preparation

[0065] Phase change material: Paraffin wax is selected, with a latent heat of phase change of 185 kJ / kg. Prepare 65 parts by mass.

[0066] Carrier materials: Nanoscale liposomes with a particle size of 80 nm, 20 parts by weight prepared; expanded graphite with a porosity of 92%, 10 parts by weight prepared.

[0067] Chemical inhibitor: 15 parts by weight are prepared by combining a slow-setting polycarboxylate superplasticizer and nano-silica at a mass ratio of 4:1.

[0068] 2. Preparation process

[0069] Phase change material encapsulation: First, paraffin wax is heated to a molten state, and nano-sized liposomes are added to the molten paraffin wax. The mixture is then ultrasonically vibrated at 200W power for 30 minutes to allow the two materials to be uniformly adsorbed and form a core-shell structure. At the same time, another portion of molten paraffin wax is injected into expanded graphite using a vacuum impregnation method. The vacuum degree is controlled at 0.08MPa, and the impregnation time is 2.5 hours. After cooling, the material is pulverized to a particle size of 1-3mm to obtain two encapsulated phase change materials.

[0070] Surface modification of encapsulated phase change materials: The two encapsulated phase change materials are mixed evenly, and a silane coupling agent is added as a surface modifier for surface modification. The mass of the silane coupling agent is 1% of the total mass of the encapsulated phase change materials.

[0071] Chemical inhibitor combined with encapsulated phase change material: The surface-modified encapsulated phase change material is mixed with the chemical inhibitor at a mass ratio of 4:1 to obtain a composite hydration heat inhibitor.

[0072] Membrane coating: The composite heat of hydration inhibitor was placed in a fluidized bed at 60°C and coated with a 100μm thick polyvinyl alcohol film to obtain a membrane-coated composite heat of hydration inhibitor.

[0073] 3. Application

[0074] Take three equal parts of concrete raw materials, labeled as groups A, B, and C. When preparing concrete, group A does not add any heat of hydration inhibitor. When preparing concrete, group B incorporates the membrane-coated composite heat of hydration inhibitor prepared in this embodiment at 4% of the total mass of cementitious materials. When preparing concrete, group C incorporates the membrane-coated composite heat of hydration inhibitor prepared in this embodiment at 4% of the total mass of cementitious materials. The remaining process methods and operating steps are the same for groups A, B, and C.

[0075] Indicator Testing

[0076] 1. Detect the initial phase change material leakage rate of composite hydration heat materials;

[0077] 2. Monitor the heating rate during the hydration process of the three groups of concrete in real time and observe the time when the temperature peak appears;

[0078] 3. Concrete compressive strength retention rate;

[0079] 4. The decrease in the peak value of the maximum hydration rate of concrete.

[0080] result

[0081] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in Group B of this embodiment was 0.8%.

[0082] The internal temperature rise curves of concrete during the preparation process of groups A, B, and C in this embodiment are shown in the attached figure. Figure 2 As shown, the 28-day compressive strength of concrete in group A remains at 61.3 MPa.

[0083] Compared with Group A, the concrete prepared in Group B had a 9.7℃ lower cumulative internal temperature rise during the initial hydration stage (0-24 hours); the temperature peak appeared 3.5 hours later; the 28-day compressive strength retention rate of Group B concrete reached 92%; and the peak value of the maximum hydration rate of Group B concrete decreased by 79.0%.

[0084] Compared with Group A, the concrete prepared in Group C had a 6.4℃ lower cumulative internal temperature rise during the initial hydration stage (0-24 hours) and a 1.4-hour delayed temperature peak appearance. The 28-day compressive strength retention rate of the concrete in Group B reached 92%, and the peak value of the maximum hydration rate of the concrete in Group B decreased by 79.0%.

[0085] Example 2

[0086] This embodiment provides a composite hydration heat inhibitor and its preparation method, as detailed below:

[0087] 1. Raw material preparation

[0088] Phase change materials: stearic acid, melting point 52℃, prepare 65 parts by mass; fatty acid ester (methyl laurate), prepare 15 parts by mass.

[0089] Carrier materials: Nanoscale liposomes, 90 nm in diameter, 15 parts by weight prepared; porous ceramic particles, density 1.1 g / cm³. 3 Prepare 5 portions.

[0090] Chemical inhibitor: 20 parts by weight are prepared by combining a slow-setting polycarboxylate superplasticizer and nano-silica at a mass ratio of 3:1.

[0091] 2. Preparation process

[0092] Phase change material encapsulation: Stearic acid was heated and melted, and the prepared nano-sized liposomes were added. The mixture was ultrasonically vibrated at 250W for 30 minutes to form a microcapsule structure. Methyl laurate was mixed with porous ceramic particles and stirred at 300r / min for 30 minutes to allow methyl laurate to be adsorbed onto the porous ceramic particles, resulting in two encapsulated phase change materials.

[0093] Surface modification of encapsulated phase change materials: Two encapsulated phase change materials are mixed, and a silane coupling agent is added as a surface modifier for surface modification. The mass of the silane coupling agent is 1.2% of the total mass of the encapsulated phase change materials.

[0094] It should be noted that the total mass of the encapsulated phase change material is the sum of the masses of the carrier material and the phase change material. The total mass of the encapsulated phase change material in subsequent embodiments is the same as in this embodiment.

[0095] Chemical inhibitor combined with encapsulated phase change material: The surface-modified encapsulated phase change material is mixed with the chemical inhibitor at a mass ratio of 5:1 to obtain a composite hydration heat inhibitor.

[0096] Membrane coating: The composite heat of hydration inhibitor was placed in a fluidized bed at 60°C and coated with a polyvinyl alcohol film with a thickness of 120 μm to obtain a membrane-coated composite heat of hydration inhibitor.

[0097] 3. Application

[0098] The process steps and methods for preparing concrete are the same as in Example 1, except that the composite hydration heat inhibitor with membrane coating prepared in this example is added at 3.5% of the total mass of cementitious materials during concrete preparation.

[0099] Indicator Testing

[0100] The indicator detection and methods are the same as in Example 1.

[0101] result

[0102] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in this embodiment is 1.2%.

[0103] Compared with the concrete prepared in Group A of Example 1, the concrete prepared in this example had a 7.5°C lower cumulative temperature rise inside the concrete during the initial stage of hydration; the temperature peak appeared 3.2 hours later; the 28-day compressive strength retention rate was 91%; and the peak value of the maximum hydration rate was reduced by 57.2%.

[0104] Example 3

[0105] This embodiment provides a composite hydration heat inhibitor and its preparation method, as detailed below:

[0106] 1. Raw material preparation

[0107] Phase change material: paraffin wax, latent heat of phase change 190kJ / kg, prepare 80 parts by weight.

[0108] Carrier materials: expanded graphite with a porosity of 95%, 10 parts by weight prepared; silica aerogel, 10 parts by weight prepared.

[0109] Chemical inhibitor: 16 parts by weight are prepared by combining a slow-setting polycarboxylate superplasticizer and nano-silica at a mass ratio of 5:1.

[0110] 2. Preparation process

[0111] Phase change material encapsulation: Paraffin wax is melted and injected into expanded graphite using a vacuum impregnation method with a vacuum degree of 0.05 MPa and an impregnation time of 3 hours. After cooling, it is pulverized to a particle size of 1-3 mm. The remaining half of the molten paraffin wax is mixed with silica aerogel and stirred at a stirring speed of 400 r / min for 40 minutes to allow the paraffin wax to be adsorbed onto the silica aerogel, thus obtaining two encapsulated phase change materials.

[0112] Surface modification of encapsulated phase change materials: Two encapsulated phase change materials are mixed, and a silane coupling agent is added as a surface modifier for surface modification. The mass of the silane coupling agent is 1.5% of the total mass of the encapsulated phase change materials.

[0113] Chemical inhibitor combined with encapsulated phase change material: The surface-modified encapsulated phase change material is mixed with the chemical inhibitor at a mass ratio of 3:1 to obtain a composite hydration heat inhibitor.

[0114] Membrane coating: The composite heat of hydration inhibitor was placed in a fluidized bed at 60°C and coated with a polyvinyl alcohol film with a thickness of 150 μm to obtain a membrane-coated composite heat of hydration inhibitor.

[0115] 3. Application

[0116] The process steps and methods for preparing concrete are the same as in Example 1, except that, when preparing concrete, the composite hydration heat inhibitor with membrane coating prepared in this example is added at 5% of the total mass of cementitious materials.

[0117] Indicator Testing

[0118] The indicator detection and methods are the same as in Example 1.

[0119] result

[0120] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in this embodiment is 0.5%.

[0121] Compared with the concrete prepared in Group A of Example 1, the concrete prepared in this example showed a 9°C reduction in the cumulative internal temperature rise during the initial hydration stage; a 3.8-hour delay in the appearance of the temperature peak; a 93% retention rate of compressive strength after 28 days; and a 81.3% reduction in the maximum hydration rate.

[0122] Example 4

[0123] This embodiment provides a composite hydration heat inhibitor and its preparation method, as detailed below:

[0124] 1. Raw material preparation

[0125] Phase change material: 60 parts by mass of palmitic acid (melting point 62-65℃) and 20 parts by mass of hydrogenated vegetable oil (latent heat of phase change 170kJ / kg).

[0126] Carrier materials: 25 parts by weight of modified zeolite molecular sieve (pore size 3-5nm) and 5 parts by weight of nano-sized liposomes (particle size 100nm).

[0127] Chemical inhibitor: The slow-setting polycarboxylate superplasticizer and nano titanium dioxide are combined at a mass ratio of 4.5:1 (total 16 parts by mass).

[0128] 2. Preparation process

[0129] Phase change material encapsulation: Palmitic acid and hydrogenated vegetable oil were melted (75°C) and injected into the pores of modified zeolite molecular sieves, then impregnated under a vacuum of 0.07 MPa for 3 hours. Nanoliposomes and molten phase change materials were then subjected to ultrasonic-microwave synergistic treatment (ultrasonic 200W, microwave 400W, 15 minutes) to form nanocapsules, resulting in two encapsulated phase change materials.

[0130] Surface modification of encapsulated phase change materials: Two encapsulated phase change materials are mixed, and a titanate coupling agent is added as a surface modifier for surface modification. The mass of the titanate coupling agent is 1.8% of the total mass of the encapsulated phase change materials.

[0131] Chemical inhibitor combined with encapsulated phase change material: The surface-modified encapsulated phase change material is mixed with the chemical inhibitor at a mass ratio of 3.5:1 to obtain a composite hydration heat inhibitor.

[0132] Membrane coating: The composite heat of hydration inhibitor was placed in a fluidized bed at 60°C and coated with an 80μm thick polydopamine film to obtain a membrane-coated composite heat of hydration inhibitor.

[0133] 3. Application

[0134] The process steps and methods for preparing concrete are the same as in Example 1, except that the composite hydration heat inhibitor with membrane coating prepared in this example is added at 3.5% of the total mass of cementitious materials during concrete preparation.

[0135] Indicator Testing

[0136] The indicator detection and methods are the same as in Example 1.

[0137] result

[0138] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in this embodiment is 1.0%.

[0139] Compared with the concrete prepared in Group A of Example 1, the concrete prepared in this example showed a 9.2°C reduction in the cumulative internal temperature rise during the initial hydration stage; a 4.1-hour delay in the appearance of the temperature peak; a 94% retention rate of compressive strength after 28 days; and a 71.3% reduction in the peak value of the maximum hydration rate. This example is particularly suitable for the preparation of high-strength concrete structures.

[0140] Example 5

[0141] This embodiment provides a composite hydration heat inhibitor and its preparation method, as detailed below:

[0142] 1. Raw material preparation

[0143] Phase change material: 65 parts by mass of n-octadecane (latent heat of phase change 240 kJ / kg).

[0144] Carrier material: 15 parts by weight of carbon nanotube sponge (porosity 98%).

[0145] Chemical inhibitor: Boric acid modified polycarboxylate superplasticizer and nano-clay are compounded at a ratio of 5:1 (total 13 parts by mass).

[0146] 2. Preparation process

[0147] Phase change material encapsulation: n-octadecane is permeated into carbon nanotube sponge under supercritical CO2 conditions (pressure 10MPa, 45℃), and then broken into 0.5-2mm particles by high-pressure microfluidic technology (150MPa) to obtain encapsulated phase change material.

[0148] Surface modification of encapsulated phase change material: A silane coupling agent is added to the encapsulated phase change material as a surface modifier for surface modification. The mass of the silane coupling agent is 0.8% of the total mass of the encapsulated phase change material.

[0149] Chemical inhibitor combined with encapsulated phase change material: The surface-modified encapsulated phase change material is mixed with the chemical inhibitor, and the mass ratio of phase change material to chemical inhibitor is 4.5:1, to obtain a composite hydration heat inhibitor.

[0150] Film coating: The composite heat of hydration inhibitor prepared in this embodiment was coated with a 50 nm alumina film using atomic layer deposition technology to obtain a film-coated composite heat of hydration inhibitor.

[0151] 3. Application

[0152] The process steps and methods for preparing concrete are the same as in Example 1, except that, when preparing concrete, the composite hydration heat inhibitor with membrane coating prepared in this example is added at 5% of the total mass of cementitious materials.

[0153] Indicator Testing

[0154] The indicator detection and methods are the same as in Example 1.

[0155] result

[0156] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in this embodiment is 0.3%.

[0157] Compared with the concrete prepared in Group A of Example 1, the concrete prepared in this example showed a reduction of 8.4°C in the cumulative internal temperature rise during the initial stage of hydration; a delay of up to 5 hours in the temperature peak; a 28-day compressive strength retention rate of 94%; and a 55% reduction in the peak hydration rate. It is suitable for high-durability concrete for marine engineering.

[0158] Example 6

[0159] This embodiment provides a composite hydration heat inhibitor and its preparation method, which is basically the same as the process method and steps in Example 1, except that...

[0160] During the membrane coating process, the composite hydration heat inhibitor was placed in a fluidized bed at 60°C and coated with a 200μm thick polyvinyl alcohol film to obtain a membrane-coated composite hydration heat inhibitor.

[0161] Indicator Testing

[0162] Preparation and testing are the same as in Example 1.

[0163] result

[0164] The initial phase change material leakage rate of the membrane-coated composite hydration heat inhibitor prepared in this embodiment is 1.8%.

[0165] Compared with the concrete in Group A of Example 1, the concrete prepared in this example had a 7.3°C lower cumulative temperature rise in the early stage of hydration; the temperature peak appeared 3.4 hours later; the 28-day compressive strength retention rate reached 90.6%; and the peak value of the maximum hydration rate was reduced by 48.5%.

[0166] As can be seen from Examples 1 to 6 above, the composite hydration heat inhibitor provided by the present invention can not only effectively control the heating rate of concrete hydration heat and reduce the peak value of the maximum hydration rate, but also ensure that the 28-day compressive strength retention rate of the prepared concrete is as high as 90% or more, that is, the prepared concrete has strong mechanical durability.

[0167] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0168] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A composite hydration heat inhibitor, characterized in that, It includes: Phase change materials; A carrier material is loaded onto the surface of the phase change material to form a shell, thus forming a core-shell structure material with the phase change material. A chemical inhibitor, wherein the chemical inhibitor is connected to a core-shell structure material modified with a surface modifier to form a composite hydration heat inhibitor; the mass ratio of the phase change material to the chemical inhibitor in the composite hydration heat inhibitor is 3~5:1; The components, by mass percentage, are: 50-80% phase change material, 10-35% carrier material, and 5-15% chemical inhibitor; the chemical inhibitor is composed of a retarded polycarboxylate superplasticizer and nanomaterials in a mass ratio of 3-5:

1.

2. The hydration heat inhibitor according to claim 1, characterized in that, The phase change material is selected from at least one of paraffin, stearic acid, and fatty acid esters; the carrier material is selected from at least one of nano-liposomes, expanded graphite, porous ceramic particles, and silica aerogel.

3. The hydration heat inhibitor according to claim 1, characterized in that, The nanomaterial is selected from at least one of silicon dioxide, titanium dioxide, clay, and hydroxyapatite.

4. The hydration heat inhibitor according to claim 1, characterized in that, The surface modifier is a silane coupling agent and / or a titanate coupling agent.

5. The hydration heat inhibitor according to claim 1, characterized in that, The composite hydration heat inhibitor also has a coating film on its surface, forming a coating body; the coating film is a polymer film or a metal oxide film; the leakage rate of the phase change material in the coating body is ≤2%, and the leakage rate is ≠0.

6. The hydration heat inhibitor according to claim 5, characterized in that, The coating film has a thickness of 50~200μm.

7. A method for preparing a composite hydration heat inhibitor according to any one of claims 1 to 6, characterized in that, It includes the following steps: Non-solid phase change materials are encapsulated and shaped using carrier materials to form core-shell structure materials; The core-shell structure material is modified using a surface modifier; A composite hydration heat inhibitor is formed by mixing surface-modified core-shell structured materials with chemical inhibitors. The mass ratio of phase change material to chemical inhibitor in the composite hydration heat inhibitor is 3~5:

1.

8. A method for applying the composite hydration heat inhibitor according to any one of claims 1 to 6, characterized in that, The composite heat of hydration inhibitor is added at 3-5% of the total mass of cementitious materials in the concrete mixture.

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