Composite hydration heat inhibitor as well as preparation method and application thereof

Abstract

The invention relates to a composite hydration heat inhibitor as well as a preparation method and application thereof. The composite hydration heat inhibitor comprises: a phase change material; the carrier material is loaded on the surface of the phase change material to form a shell, and the carrier material and the phase change material form a core-shell structure material; the chemical inhibitor is connected with the core-shell structure material modified by the 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 technical problem to be solved is how to provide the composite hydration heat inhibitor, increase the content of a phase change material in the composite hydration heat inhibitor, avoid direct contact between a large amount of the phase change material and concrete, reduce the use amount of a chemical inhibitor and improve the durability of the mechanical strength of the concrete.

Description

Technical Field

[0001] The present invention belongs to the field of concrete, and particularly relates to a composite heat of hydration inhibitor, a preparation method thereof, and an application thereof. Background Art

[0002] The problem of concrete temperature cracks is a major problem that must be faced in the field of civil engineering. In order to suppress or even avoid the occurrence of concrete crack problems, the commonly used technical means nowadays include laying cooling water pipes and adding external inhibitors that can regulate the heat of hydration of cement.

[0003] A document discloses a temperature-controlled phase change release type heat of hydration regulation material, a preparation method thereof, and an application thereof. The heat of hydration regulation material is a core-shell structure, which includes a carrier loaded with a cement hydration inhibition material and a coating formed by coating a phase change wax on the surface of the carrier. The phase change wax is used as the outer shell material. During the use process, it can better control the total amount of heat released in the early stage of concrete, control the rate of cement hydration reaction, thereby reducing the maximum temperature rise inside the concrete, reducing the temperature difference between its inside and outside, so as to achieve the purpose of reducing concrete temperature shrinkage cracks and reducing the risk of concrete cracking.

[0004] However, for the temperature-controlled phase change release type heat of hydration regulation material disclosed in the foregoing prior art, using a phase change material as the coating will cause a large amount of the phase change material to directly contact the concrete, absorb a large amount of heat of hydration, affect the gelling rate of the concrete, and will affect the strength of the concrete. More importantly, it will affect the durability of the mechanical properties of the concrete; and using 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 purpose of the present invention is to provide a composite heat of hydration inhibitor, a preparation method thereof, and an application thereof. The technical problem to be solved is how to provide a composite heat of hydration inhibitor, increase the content of the phase change material in the composite heat of hydration inhibitor, and avoid a large amount of the phase change material directly contacting the concrete, reduce the usage amount of chemical inhibitors, and improve the durability of the mechanical strength of the concrete.

[0006] The object of the present invention and the technical problems to be solved are achieved by the following technical solutions. A composite heat of hydration inhibitor according to the present invention includes:

[0007] A phase change material;

[0008] A carrier material, the carrier material 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;

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

[0010] The object of the present invention and the technical problems to be solved can also be further realized by the following technical measures.

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

[0012] Preferably, in the foregoing hydration heat inhibitor, 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-scale liposomes, expanded graphite, porous ceramsite and silica aerogel.

[0013] Preferably, in the foregoing hydration heat inhibitor, the chemical inhibitor is composed of a retarder polycarboxylate water reducer and a nano material in a mass ratio of 3-5:1.

[0014] Preferably, in the foregoing hydration heat inhibitor, the nano material is selected from at least one of silicon dioxide, titanium dioxide, clay and hydroxyapatite.

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

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

[0017] Preferably, in the foregoing hydration heat inhibitor, the thickness of the coating film is 50-200 μm.

[0018] The object of the present invention and the technical problems to be solved are also realized by the following technical solutions. A preparation method of a composite hydration heat inhibitor according to the present invention includes the following steps:

[0019] Encapsulating and shaping a non-solid phase change material with a carrier material to form a core-shell structure material;

[0020] Modifying the core-shell structure material with a surface modifier;

[0021] Mixing the surface-modified core-shell structure material with a chemical inhibitor to form a composite hydration heat inhibitor;

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

[0023] The application method of the composite heat of hydration inhibitor proposed according to the foregoing solution of the present invention is also implemented by the following technical solution. Among them, the composite heat of hydration inhibitor is incorporated at 3-5% of the total mass of the cementitious materials in the concrete mixture.

[0024] By means of the above technical solution, a composite heat of hydration inhibitor and its preparation method and application proposed by the present invention have at least the following advantages:

[0025] A composite heat of hydration inhibitor and its preparation method and application provided by the present invention form a core-shell structure material by loading a carrier material on the surface of the phase change material, and further adding a chemical inhibitor to form a composite heat of hydration inhibitor. The chemical inhibitor helps to stimulate the outer shell of the core-shell structure material under the action of the heat of hydration, and assists in controlling the gradual dissolution of the outer shell of the carrier material to control the gradual release of the phase change material. In this way, not only can a large amount of phase change material be prevented from directly contacting the cementitious materials in the concrete, but also the amount of chemical inhibitor used is effectively reduced, thereby avoiding affecting the hydration rate of the cementitious materials and ensuring the mechanical durability of the concrete.

[0026] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following describes in detail with reference to the preferred embodiments of the present invention and the accompanying drawings. Brief Description of the Drawings

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

[0028] Figure 2 It is the internal temperature rise curve of the concrete during the preparation of the concrete in Group A, Group B, and Group C in Example 1. Detailed Description of the Embodiments

[0029] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following describes in detail with reference to the accompanying drawings and preferred embodiments a composite heat of hydration inhibitor and its preparation method and application proposed according to the present invention. Its specific implementation manner, structure, characteristics and effects are described in detail as follows.

[0030] The present invention provides a composite heat of hydration inhibitor, which includes:

[0031] A phase change material;

[0032] 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, as shown in the attachment Figure 1 As shown in the figure, 1 is the phase change material, 2 is the carrier material shell, and 3 is the chemical inhibitor.

[0033] A chemical inhibitor, which is connected with the surface-modified core-shell structure material 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.

[0034] In the foregoing solution, the phase change material absorbs heat during the hydration process of concrete by using its phase change heat, thereby reducing the rising rate of the internal temperature of the concrete. In order to enable the phase change material to better regulate the hydration heat, in some embodiments, the phase change material preferably has a latent heat release peak that matches the hydration heat release peak of the cementitious material. Since the heat release peak during the hydration process of the cementitious material cement is generally in the range of 12-48 hours, therefore, in the present invention, the latent heat release peak of the phase change material is 12-48 hours; further preferably, the phase change material is an organic phase change material. In some other embodiments, the phase change material used is at least one of paraffin, stearic acid, and fatty acid esters. Under this condition, the latent heat release peak of the phase change material matches the heat release peak of the hydration of the cementitious material cement better, which is more conducive to regulating the hydration heat of the cementitious material cement.

[0035] In the foregoing solution, the carrier material is used to encapsulate the phase change material. The carrier material serves as a shell and forms a core-shell structure with the phase change material to prevent a large amount of leakage of the phase change material and at the same time helps to improve the thermal stability of the phase change material. In order to make the carrier material have good compatibility with the phase change material, in some embodiments, the carrier material is preferably at least one of nanoscale liposomes, expanded graphite (porosity ≥ 90%), porous ceramsite, and silica aerogel.

[0036] In the foregoing solution, the chemical inhibitor is used to regulate the cement hydration rate, extend the hydration induction period, and help to stimulate the shell of the core-shell structure material under the action of hydration heat, so that the carrier shell gradually dissolves to control the gradual release of the phase change material. The chemical inhibitor of the present 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 of the present invention can effectively play a role during the peak period of hydration heat release. In some embodiments, the chemical inhibitor is composed of a retardant polycarboxylate superplasticizer and nano-silica in a mass ratio of 3-5:1. Nano-silica can also refine the pore structure of the concrete, improve the density of the concrete, reduce the concentrated release of hydration heat, and help to enhance the mechanical strength of the concrete; further preferably, in some other embodiments, the nano material is selected from at least one of silica, titanium dioxide, clay, and hydroxyapatite. Under this condition, the strength of the obtained concrete is good and the material is relatively more economical.

[0037] In the foregoing solution, in order to enhance the connection tightness and interfacial compatibility between the chemical inhibitor and the carrier, and thus achieve a dual blockade of the phase change material, reduce the leakage and dispersion of the phase change material, some embodiments use a surface modifier as a silane coupling agent and / or a titanate coupling agent.

[0038] In the foregoing solution, in order to enable the phase change material, the carrier material, and the chemical inhibitor to interact and cooperate better, in some embodiments, further preferably, in terms of mass percentage, the content of each component is: 50-80% phase change material, 10-35% carrier material, 5-15% chemical inhibitor; in some other embodiments, preferably, the content of each component is: 50-70% phase change material, 15-35% carrier material, 10-15% chemical inhibitor; the mass percentage of each component in the foregoing solution is strictly controlled to ensure the full play of its retarding effect and refinement effect, and at the same time avoid having an adverse impact on the mechanical properties of the concrete.

[0039] In the foregoing solution, in order to improve the stability of the composite hydration heat inhibitor described in the present invention, the surface of the composite hydration heat inhibitor further includes a coating film to form a coated body. In order to enable the phase change material to absorb the heat released in the early stage of the concrete, the leakage rate of the phase change material in the coated body is ≤2%, and the leakage rate ≠ 0. Further, in order to enable the chemical inhibitor in the composite hydration heat inhibitor to be gradually released together with the phase change material and steadily control the heat accumulation in the concrete, some embodiments preferably use the coating film as a polymer thin film (such as a polyvinyl alcohol thin film, a polydopamine thin film), and in some other embodiments, the film layer used is a metal oxide film, such as a titanium oxide thin film, an aluminum oxide thin film. In order to better control the gradual release of the phase change material, further preferably, in some embodiments, the thickness of the coating film is 50-200 μm.

[0040] A composite hydration heat inhibitor provided by the present invention includes a phase change material, a carrier material, and a chemical inhibitor that act synergistically. The presence of the chemical inhibitor is beneficial to the exertion of the performance of the carrier-phase change material combination, and the chemical inhibitor can extend the efficiency of the cement hydration reaction and prolong the hydration induction period, thereby reducing the early temperature rise rate of the concrete. This retardation effect complements the physical adsorption mechanism of the phase change material to form a dual temperature control mechanism, which can effectively control the release of hydration heat at different stages. The composite hydration heat inhibitor of the present invention not only effectively controls the hydration heat of the concrete, but also improves the mechanical properties and durability retention of the concrete, and has a broader application prospect and higher technical content.

[0041] The present invention also provides a preparation method of a composite hydration heat inhibitor, which includes the following steps:

[0042] Phase change material encapsulation: A carrier material is used to encapsulate and shape a non-solid phase change material to form a core-shell structured material. In some embodiments, paraffin is loaded into expanded graphite by the vacuum impregnation method to achieve the encapsulation of the phase change material paraffin by the carrier material expanded graphite, forming a core-shell structured material 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 other embodiments, the carrier material is a nanoscale liposome with a particle size of ≤ 100 nm, and it is uniformly adsorbed with molten paraffin (phase change material) through ultrasonic oscillation for 30 minutes to achieve the encapsulation of paraffin, forming a microcapsule-type core-shell structure. In other embodiments, using a nanoscale liposome as the carrier and stearic acid as the phase change material, the foregoing scheme is adopted to achieve the encapsulation of stearic acid, forming a microcapsule-type core-shell structure.

[0043] Composite process: The encapsulated phase change material, that is, the core-shell structured material of the present invention, is modified with a surface modifier. In some embodiments, a silane coupling agent is added as the surface modifier, which not only helps to successfully complete the combination of the core-shell structured material and the chemical inhibitor in the subsequent process, but also helps to increase the tight combination degree between the phase change material and the carrier material. The surface-modified core-shell structured material is mixed with a chemical inhibitor to form a composite heat of hydration inhibitor; wherein, the mass ratio of the phase change material to the chemical inhibitor in the composite heat of hydration inhibitor is 3 - 5:1. Strictly controlling the mass ratio of the phase change material to the chemical inhibitor in the composite heat of hydration inhibitor is not only more conducive to ensuring the control of the heat of hydration of concrete by the composite heat of hydration inhibitor formed by the present invention, but also can better achieve the 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] For the foregoing technical solution, further preferably, at least two process technologies are used to load the carrier on the surface of the phase change material for encapsulation. The core-shell structured materials obtained by multiple process encapsulations are mixed, and then the mixed core-shell structured materials are surface-modified. The surface-modified mixed core-shell structured materials are mixed with a chemical inhibitor so that the chemical inhibitor can be connected to the surface of the mixed core-shell structured materials to achieve a double blockade of the phase change material. In some embodiments, the ultrasonic oscillation method and the vacuum impregnation method are respectively used to load the carrier material on the surface of the phase change material to form a core-shell structured material, and then they are mixed to form a mixed core-shell structured material. In this way, it is easy to achieve the balance between leakage control and heat conduction efficiency, and the formed core-shell structure is tightly combined with the porous load and has good stability. This is suitable for large-volume concrete that requires a multi-level temperature control mechanism, and the mixing process can meet both microscopic and macroscopic requirements.

[0045] Preferably, in some other embodiments, in order to further improve the stability of the composite heat of hydration inhibitor, a fluidized bed process is also adopted 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; more preferably, in some other embodiments, the coating thickness of the film is 50-200 μm; after coating the film, the leakage rate of the phase change material is ≤2%, and the leakage rate ≠0; in some other embodiments, a metal oxide film with good tear resistance, strong thermal stability and degradability is used, such as an alumina film layer or a titanium oxide film layer for the composite heat of hydration inhibitor, to enhance the stability of the composite heat of hydration inhibitor.

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

[0047] The present invention also provides an application method of the composite heat of hydration inhibitor described in the foregoing solution. In some embodiments, the composite heat of hydration inhibitor is incorporated at 3-5% of the total mass of the cementitious materials in the concrete. Using the composite heat of hydration inhibitor described in the present invention under this condition can not only effectively control the temperature rise rate and temperature of the concrete, but also ensure good mechanical strength durability of the prepared concrete.

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

[0049] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well-known to those skilled in the art; unless otherwise specified, the methods are all well-known methods in the art. Unless otherwise defined, the technical terms or scientific terms used should have the ordinary meaning understood by those of ordinary skill in the art to which the present invention belongs.

[0050] In the following embodiments of the present invention, the concrete components are as follows: in parts by mass, it includes:

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

[0052] Among them, the cement is 42.5 low-heat portland cement, the slag powder is S95 grade slag powder, the fly ash is first-class fly ash, the silica fume is microsilica (specific surface area ≥15,000m 2 / kg), the sand is medium sand with a fineness modulus of 2.6, and the coarse aggregate is 5-20mm continuously graded gravel.

[0053] The test index tests and calculation methods involved in the following embodiments and comparative examples of the present invention are as follows:

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

[0055] Retaining rate of concrete compressive strength: Taking the 28-day compressive strength of the concrete without the composite hydration heat inhibitor as K 1 , and the 28-day compressive strength of the concrete obtained by incorporating the composite hydration inhibitor is K 2 , the retaining rate of concrete compressive strength = (K 1 - K 2 ) / K 2 ×100%; the retaining rate of the 28-day compressive strength of the concrete without the composite hydration heat inhibitor is 100%.

[0056] Reduction amplitude of the maximum hydration rate peak of concrete: Taking the maximum hydration rate peak of the concrete without the composite hydration heat inhibitor as α 1 , and the maximum hydration rate peak of the concrete obtained by incorporating the composite hydration inhibitor is α 2 , the reduction amplitude of the maximum hydration rate peak of the concrete incorporated with the composite hydration inhibitor is (α 1 - α 2 ) / α 1 ×100%.

[0057] Initial phase change material leakage rate of the composite hydration heat material: Tested by the weight loss method, and the specific steps are as follows:

[0058] 1. Sample pretreatment:

[0059] Place the composite hydration heat inhibitor in a constant temperature oven at 60°C for 24 hours to simulate the high-temperature environment in the initial stage of concrete hydration. Weigh the initial mass (m 0 ), accurate to 0.1 mg.

[0060] 2. Test:

[0061] Heat up to a temperature condition 10°C higher than the melting point of the phase change material to simulate the concrete hydration temperature rise process, weigh the remaining mass (m 1 ), and calculate the initial leakage rate: Leakage rate = (m 0 - m 1 ) / m 0 ×100%.

[0062] Example 1

[0063] This example provides a composite hydration heat inhibitor and its preparation method, specifically as follows:

[0064] 1. Raw material preparation

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

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

[0067] Chemical inhibitor: A retarding polycarboxylate superplasticizer and nano-silica are composed in a mass ratio of 4:1, and 15 parts by mass are prepared.

[0068] 2. Preparation process

[0069] Encapsulation of phase change material: First, heat the paraffin wax to a molten state, add the nanoscale liposomes to the molten paraffin wax, and oscillate with ultrasonic waves at a power of 200 W for 30 minutes to make the two adsorb evenly to form a core-shell structure; at the same time, use the vacuum impregnation method to inject another part of the molten paraffin wax into the expanded graphite, control the vacuum degree at 0.08 MPa, and the impregnation time is 2.5 hours. After cooling, crush it to a particle size of 1 - 3 mm to obtain two kinds of encapsulated phase change materials.

[0070] Surface modification of the encapsulated phase change material: Mix the above two kinds of encapsulated phase change materials evenly, and add a silane coupling agent 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 material.

[0071] Compound of chemical inhibitor and encapsulated phase change material: Mix the surface-modified encapsulated phase change material with the chemical inhibitor, and the mass ratio of the phase change material to the chemical inhibitor is 4:1 to obtain a composite heat of hydration inhibitor.

[0072] Film coating: Place the composite heat of hydration inhibitor in a fluidized bed at 60 °C and coat it with a 100 - μm - thick polyvinyl alcohol film to obtain a film - coated composite heat of hydration inhibitor.

[0073] 3. Application

[0074] Take 3 equal parts of concrete raw materials, denoted as groups A, B, and C. When preparing concrete, no heat of hydration inhibitor is added to group A. When preparing concrete in group B, during the preparation of concrete, add the film - coated composite heat of hydration inhibitor prepared in this example at 4% of the total mass of the cementitious materials. When preparing concrete in group C, during the preparation of concrete, add the composite heat of hydration inhibitor prepared in this example but without the film coating at 4% of the total mass of the cementitious materials. The remaining process methods and operating steps of groups A, B, and C are the same.

[0075] Index detection

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

[0077] 2. Monitor the temperature rise rate during the hydration process of 3 groups of concrete in real time and observe the time when the temperature peak appears;

[0078] 3. Retention rate of concrete compressive strength;

[0079] 4. Reduction amplitude of the maximum hydration rate peak value of concrete.

[0080] Results

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

[0082] During the preparation of concrete in Group A, Group B and Group C of this example, the internal temperature rise curve of the concrete is as shown in the appendix Figure 2 The 28-day compressive strength retention of the concrete in Group A is 61.3 MPa.

[0083] Compared with Group A, during the initial stage of concrete hydration (0 - 24 hours) in Group B, the cumulative temperature rise inside the concrete decreased by 9.7 °C; the time when the temperature peak appeared was delayed by 3.5 hours; the 28-day compressive strength retention rate of the concrete in Group B reached 92%, and the reduction amplitude of the maximum hydration rate peak value of the concrete in Group B was 79.0%.

[0084] Compared with Group A, during the initial stage of concrete hydration (0 - 24 hours) in Group C, the cumulative temperature rise inside the concrete decreased by 6.4 °C; the time when the temperature peak appeared was delayed by 1.4 hours; the 28-day compressive strength retention rate of the concrete in Group B reached 92%, and the reduction amplitude of the maximum hydration rate peak value of the concrete in Group B was 79.0%.

[0085] Example 2

[0086] This example provides a composite heat of hydration inhibitor and its preparation method, which are specifically as follows:

[0087] 1. Raw material preparation

[0088] Phase change material: Stearic acid, melting point 52 °C, prepare 65 parts by mass; Fatty acid ester (methyl laurate), prepare 15 parts by mass.

[0089] Carrier material: Nanoscale liposome, particle size 90 nm, prepare 15 parts by mass; Porous ceramsite, density 1.1 g / cm 3 , prepare 5 parts by mass.

[0090] Chemical inhibitor: Composed of a retarder polycarboxylate superplasticizer and nano-silica in a mass ratio of 3:1, prepare 20 parts by mass.

[0091] 2. Preparation process

[0092] Phase change material encapsulation: Heat stearic acid until it melts, add the prepared nanoscale liposomes, and oscillate with ultrasonic waves at a power of 250 W for 30 minutes to form a microcapsule structure; Mix methyl laurate with porous ceramsite, and stir for 30 minutes under the condition that the stirring speed is 300 r / min to make methyl laurate adsorbed on the porous ceramsite, obtaining two kinds of encapsulated phase change materials.

[0093] Surface modification of the encapsulated phase change materials: Mix the two kinds of encapsulated phase change materials, add a silane coupling agent as a surface modifier for surface modification, and 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 materials is the sum of the masses of the carrier material and the phase change material, and the total mass of the encapsulated phase change materials in the subsequent examples is the same as that in this example.

[0095] Compound of chemical inhibitor and encapsulated phase change materials: Mix the surface-modified encapsulated phase change materials with a chemical inhibitor, and the mass ratio of the phase change material to the chemical inhibitor is 5:1 to obtain a composite hydration heat inhibitor.

[0096] Film coating: Place the composite hydration heat inhibitor in a fluidized bed at 60 °C and coat it with a polyvinyl alcohol film with a thickness of 120 μm to obtain a film-coated composite hydration heat inhibitor.

[0097] 3. Application

[0098] The process steps and methods are the same as those in Example 1 when preparing concrete, except that when preparing concrete, the film-coated composite hydration heat inhibitor prepared in this example is incorporated at 3.5% of the total mass of the cementitious materials.

[0099] Index detection

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

[0101] Results

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

[0103] Compared with the concrete prepared in Group A of Example 1, for the concrete prepared in this example, at the initial stage of hydration, the cumulative temperature rise inside the concrete is reduced by 7.5 °C; the time when the temperature peak appears is delayed by 3.2 hours; the 28-day compressive strength retention rate is 91%, and the reduction amplitude of the peak value of the maximum hydration rate is 57.2%.

[0104] Example 3

[0105] This example provides a composite hydration heat inhibitor and its preparation method, which are as follows:

[0106] 1. Raw material preparation

[0107] Phase change material: Paraffin wax, with a phase change latent heat of 190 kJ / kg, 80 mass parts are prepared.

[0108] Carrier material: Expanded graphite, with a porosity of 95%, 10 mass parts are prepared; silica aerogel, 10 mass parts are prepared.

[0109] Chemical inhibitor: A retarding polycarboxylate superplasticizer and nano-silica are composed in a mass ratio of 5:1, 16 mass parts are prepared.

[0110] 2. Preparation process

[0111] Phase change material encapsulation: Melt the paraffin wax, and inject it into the expanded graphite by the vacuum impregnation method, with a vacuum degree of 0.05 MPa and an impregnation time of 3 hours, then cool and crush it to a particle size of 1 - 3 mm; Mix the remaining half of the molten paraffin wax with the silica aerogel, and stir at a stirring speed of 400 r / min for 40 minutes to make the paraffin wax adsorbed on the silica aerogel, obtaining two kinds of encapsulated phase change materials.

[0112] Surface modification of the encapsulated phase change material: Mix the two kinds of encapsulated phase change materials, and add a silane coupling agent as a surface modifier for surface modification, and the mass of the silane coupling agent is 1.5% of the total mass of the encapsulated phase change materials.

[0113] Compound the chemical inhibitor with the encapsulated phase change material: Mix the surface-modified encapsulated phase change material with the chemical inhibitor, and the mass ratio of the phase change material to the chemical inhibitor is 3:1, obtaining a composite hydration heat inhibitor.

[0114] Film coating: Place the composite hydration heat inhibitor in a fluidized bed at 60 °C, and coat a polyvinyl alcohol film with a thickness of 150 μm to obtain a film-coated composite hydration heat inhibitor.

[0115] 3. Application

[0116] It is the same as the process steps and methods in Example 1 when preparing concrete, the difference is that when preparing concrete, the film-coated composite hydration heat inhibitor prepared in this example is incorporated at 5% of the total mass of the cementitious materials.

[0117] Index detection

[0118] The index detection and method are the same as those in Example 1.

[0119] Result

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

[0121] Compared with the concrete prepared in Group A of Example 1, the concrete prepared in this example has a 9°C reduction in the cumulative temperature rise inside the concrete during the early hydration stage; the time to peak temperature is delayed by 3.8 hours; the 28-day compressive strength retention rate reaches 93%, and the peak reduction in the maximum hydration rate is 81.3%.

[0122] Example 4

[0123] This example provides a composite hydration heat inhibitor and its preparation method, which are as follows:

[0124] 1. Raw material preparation

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

[0126] Carrier material: 25 parts by mass of modified zeolite molecular sieve (pore size 3 - 5 nm), 5 parts by mass of nanoscale liposome (particle size 100 nm).

[0127] Chemical inhibitor: A retarding polycarboxylate superplasticizer and nano-titanium dioxide are composed in 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 are compounded and melted (75°C), injected into the pores of the modified zeolite molecular sieve, and impregnated at a vacuum of 0.07 MPa for 3 hours. Nano-liposomes and the molten phase change material are formed into nano-capsules through ultrasonic-microwave synergistic treatment (ultrasonic 200 W, microwave 400 W, 15 minutes) to obtain two encapsulated phase change materials.

[0130] Surface modification of the encapsulated phase change material: The 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 material.

[0131] Compound of the chemical inhibitor and the encapsulated phase change material: The surface-modified encapsulated phase change material and the chemical inhibitor are mixed. The phase change material and the chemical inhibitor are in a mass ratio of 3.5:1 to obtain a composite hydration heat inhibitor.

[0132] Film coating: The composite hydration heat inhibitor is placed in a fluidized bed at 60°C, and a polydopamine film with a thickness of 80 μm is coated to obtain a film-coated composite hydration heat inhibitor.

[0133] 3. Application

[0134] The process steps and methods for preparing concrete are the same as those in Example 1, except that when preparing concrete, the membrane-coated composite heat of hydration inhibitor prepared in this example is incorporated at 3.5% of the total mass of the cementitious materials.

[0135] Index detection

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

[0137] Results

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

[0139] Compared with the concrete prepared in Group A of Example 1, for the concrete prepared in this example, at the initial stage of hydration, the cumulative temperature rise inside the concrete is reduced by 9.2 °C; the time to reach the temperature peak is delayed by 4.1 hours; the 28-day compressive strength retention rate is 94%, and the reduction amplitude of the peak value of the maximum hydration rate is 71.3%. This example is particularly suitable for the preparation of high-strength concrete structures.

[0140] Example 5

[0141] This example provides a composite heat of hydration inhibitor and its preparation method, specifically as follows:

[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 mass of carbon nanotube sponge (porosity 98%).

[0145] Chemical inhibitor: A composite of boric acid-modified polycarboxylate superplasticizer and nano-clay in a ratio of 5:1 (total 13 parts by mass).

[0146] 2. Preparation process

[0147] Phase change material encapsulation: n-octadecane penetrates carbon nanotube sponge under supercritical CO 2 conditions (pressure 10 MPa, 45 °C), and is broken into 0.5 - 2 mm particles through high-pressure microfluidization technology (150 MPa) to obtain the encapsulated phase change material.

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

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

[0150] Film coating: The composite hydration heat inhibitor prepared in this example is coated with a 50-nm alumina thin film by atomic layer deposition technology to obtain a film-coated composite hydration heat inhibitor.

[0151] 3. Application

[0152] The process steps and methods are the same as those in Example 1 when preparing concrete, except that when preparing concrete, the film-coated composite hydration heat inhibitor prepared in this example is incorporated at 5% of the total mass of the cementitious materials.

[0153] Index detection

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

[0155] Results

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

[0157] Compared with the concrete prepared in Group A of Example 1, for the concrete prepared in this example, at the initial stage of hydration, the cumulative temperature rise inside the concrete is reduced by 8.4 °C; the temperature peak is delayed by up to 5 hours; the 28-day compressive strength retention rate of the concrete reaches 94%, and the reduction amplitude of the peak value of the maximum hydration rate is 55%, which is applicable to high-durability concrete for marine engineering.

[0158] Example 6

[0159] This example 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 film coating process, the composite hydration heat inhibitor is placed in a fluidized bed at 60 °C and coated with a 200-μm-thick polyvinyl alcohol film to obtain a film-coated composite hydration heat inhibitor.

[0161] Index detection

[0162] The preparation detection is the same as that in Example 1.

[0163] Results

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

[0165] Compared with the concrete in Group A of Example 1, the concrete prepared in this example has a 7.3 °C reduction in the cumulative temperature rise inside the concrete during the initial stage of hydration; the time to the peak temperature is delayed by 3.4 hours; the 28-day compressive strength retention rate reaches 90.6%, and the reduction in the peak value of the maximum hydration rate is 48.5%.

[0166] As can be seen from the above Examples 1 to 6, by using the composite heat of hydration inhibitor provided by the present invention, not only can the heat of hydration rising rate of the concrete be effectively controlled, the peak value of the maximum hydration rate be reduced, but also the 28-day compressive strength retention rate of the prepared concrete is as high as over 90%, that is, the mechanical durability of the prepared concrete is strong.

[0167] The technical features in the claims and / or the specification of the present invention can be combined, and the combination method is not limited to the combination obtained through the citation relationship in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification also fall within the protection scope of the present invention.

[0168] The above are only the preferred embodiments of the present invention, and do not impose any formal limitations on the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims

1. A composite hydration heat inhibitor, characterized in that: It includes: Phase change materials; A carrier material, wherein the carrier material 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; A chemical inhibitor is connected with 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.

2. The hydration heat inhibitor according to claim 1, characterized in that: Calculated by mass percentage, the content of each component is: 50-80% phase change material, 10-35% carrier material, and 5-15% chemical inhibitor.

3. 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 ester; the carrier material is selected from at least one of nano-liposome, expanded graphite, porous ceramsite and silica aerogel.

4. The hydration heat inhibitor according to claim 1, characterized in that: The chemical inhibitor is composed of a slow-setting polycarboxylic acid water reducer and nanomaterials in a mass ratio of 3 to 5:

1.

5. The hydration heat inhibitor according to claim 4, characterized in that: The nano material is selected from at least one of silicon dioxide, titanium dioxide, clay and hydroxyapatite.

6. 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.

7. The hydration heat inhibitor according to claim 1, characterized in that: The surface of the composite hydration heat inhibitor also has a coating 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.

8. The hydration heat inhibitor according to claim 7, characterized in that: The coating film has a thickness of 50 to 200 μm.

9. A method for preparing a composite hydration heat inhibitor, characterized in that: It includes the following steps: The non-solid phase change material is encapsulated and shaped using a carrier material to form a core-shell structure material; Modifying the core-shell structure material with a surface modifier; The surface-modified core-shell structure material is mixed with a chemical inhibitor to form a composite hydration heat inhibitor; The mass ratio of the phase change material in the composite hydration heat inhibitor to the chemical inhibitor is 3 to 5:

1.

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

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