Concrete temperature rise inhibitor as well as preparation method and use method thereof

Abstract

The invention discloses a concrete temperature rise inhibitor as well as a preparation method and a use method thereof. The preparation method of the concrete temperature rise inhibitor comprises the following steps: adding sodium bicarbonate into water, uniformly stirring, adding sodium alginate, and performing ultrasonic dispersion to form a mixed solution A; heating the mixed solution A, adding phase change particles, and ultrasonically dispersing uniformly to form a mixed emulsion B; dropwise adding the mixed emulsion B into a calcium salt solution to react to form microspheres C; adding the microspheres C into a water glass solution, reacting and filtering to obtain microsphere particles D; and drying the microspheres D, vacuumizing the microspheres D, and adding the microspheres D into a magnetofluid solution to obtain the temperature rise inhibitor. The phase change particles are paraffin or lauric acid. The temperature rise inhibitor disclosed by the invention can effectively control the temperature rise of mass concrete and prevent leakage, and has small influence on mechanical properties; the temperature rise inhibitor with different phase change particles is distributed in the concrete in a gradient manner, so that the stable and good control of the internal and external temperature difference is realized, the generation of temperature cracks is reduced, and the volume stability is improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a concrete temperature rise inhibitor and its preparation and application methods. Background Technology

[0002] Construction projects often involve large volumes of concrete, such as foundation slabs, bridge abutments, and concrete dams. After pouring and molding, the cement hydration process generates a significant amount of heat. This heat needs to be released and diffused outwards, but due to the large volume and poor thermal conductivity of concrete, heat transfer from the interior is slow. This causes heat to accumulate inside the concrete, leading to a substantial increase in internal temperature, sometimes exceeding 70°C. Meanwhile, the outer surface releases heat quickly, with its temperature approaching the ambient temperature, creating a large temperature difference between the inside and outside of the concrete structure. This temperature difference results in uneven expansion and contraction, leading to thermal stress. When this stress exceeds the concrete structure's tolerance, thermal cracks will form, compromising the structural safety. Therefore, controlling the formation of thermal cracks is crucial, and the key to controlling thermal cracks lies in controlling the internal temperature rise.

[0003] Currently, methods for controlling temperature rise mainly include pre-embedded cooling water pipes, using low-heat cement or admixtures such as fly ash, thermal insulation curing to reduce external temperature loss, and using temperature rise inhibitors. However, pre-embedded cooling water pipes lead to high concrete costs, complex construction, and the risk of leakage; improper control of the cooling rate may cause "cold shock." Using low-heat cement and fly ash can control temperature rise to some extent, but it is difficult to cope with the high hydrothermal activity of high-strength concrete with high cement content. Thermal insulation curing helps reduce the temperature difference between the inside and outside, but its effect is limited and it is more harmful than helpful in reducing the internal temperature rise peak. Temperature rise inhibitors mainly use retardering as the core component, which often leads to a decrease in concrete strength. Therefore, the development of new temperature control materials is crucial. Currently, incorporating phase change materials into concrete is a new research and application hotspot for controlling internal temperature rise. Phase change materials undergo phase changes when the internal temperature of concrete rises, such as changing from solid to liquid, absorbing and storing a large amount of heat while their own temperature remains unchanged, which is beneficial for controlling the internal temperature of concrete. However, the use of phase change materials such as paraffin can lead to a decrease in concrete strength and easy leakage of liquid. Traditional microcapsule methods are prone to breakage during concrete mixing, affecting the effect. In addition, the dosage of these phase change materials is usually low, so their effect on improving internal temperature rise is limited. Summary of the Invention

[0004] To address the problems existing in the above-mentioned background technology, the present invention provides a temperature rise inhibitor that can effectively control the temperature rise of large-volume concrete, prevent leakage, and has little impact on mechanical properties, as well as its preparation method and application method.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for preparing a concrete temperature rise inhibitor includes the following steps: (1) First, sodium bicarbonate is added to water and stirred evenly. Then sodium alginate is added and dispersed by ultrasonication to form a mixture A. The purpose of this step is to form a mixture of sodium alginate and sodium bicarbonate. Sodium bicarbonate is affected by the solubility and cannot be completely dissolved. Therefore, the viscosity of sodium alginate is used to form a suspension mixture, so that sodium bicarbonate is evenly dispersed. The ultrasonic frequency is 20~25kHz, and the ultrasonic dispersion time is 8~12min; (2) Heat the mixture A obtained in step (1) and add phase change particles. After ultrasonic dispersion, a mixed emulsion B is formed. The temperature of the mixture A is higher than the melting temperature of the phase change particles. The purpose is to ensure that the phase change particles are in a molten state and form a mixed emulsion of sodium bicarbonate, sodium alginate and phase change particles. The phase change particles are paraffin or lauric acid, wherein the phase change temperature of paraffin is 58~64℃ and the phase change temperature of lauric acid is 42~46℃. The heating temperature range of the mixture A is the highest melting point of the selected phase change particles +1℃~64℃. The ultrasonic frequency is 20~30kHz, and the ultrasonic dispersion time is 3~5min; The mass fractions of each raw material in steps (1) and (2) are as follows: Sodium bicarbonate 20-30 parts, Sodium alginate 0.1~0.2 parts, 100 parts water 30-40 parts of phase change particles; (3) The mixed emulsion B obtained in step (2) is added dropwise into an excess calcium salt solution and reacted for 20-25 seconds to form microspheres C; The calcium salt solution has a mass concentration of 0.2-0.5%, wherein the calcium salt is selected from any one of calcium chloride, calcium nitrate, and calcium bicarbonate; the calcium salt solution is at room temperature, below 30°C. Mixed emulsion B is formed into particles with a diameter of no more than 2 mm and dropped into a calcium salt solution. In the presence of sodium alginate, calcium alginate microspheres are formed, and the microspheres are filled with a mixture of sodium alginate and paraffin or lauric acid. Due to the low concentration of calcium salt, by controlling the reaction time, the formed calcium alginate microspheres are spherical particles with a certain thickness and porous shape. Specifically, mixed emulsion B is added into a syringe with a needle hole diameter of no more than 1 mm. Mixed emulsion B is extruded from top to bottom in a vertical direction through the needle hole outlet, forming droplets no larger than 2 mm as it falls in the air, with one or more needle holes.

[0006] (4) Microspheres C, which are taken out from the solution after the reaction in step (3), are added to an excess of water glass solution for reaction and filtration to obtain microsphere particles D. The surface of microsphere C is a porous coating of calcium alginate. After being added to the water glass solution, calcium ions react with silicate ions to generate calcium silicate crystals and precipitates, which transforms the calcium alginate coating into a calcium silicate coating, thereby increasing the hardness of the coating. The water glass has a modulus of 2 to 2.5 and a solution mass concentration of 20 to 30%. The reaction time is 6-8 hours; (5) After drying the microspheres D obtained in step (4), remove the moisture, vacuum them and add them to an excess of magnetic fluid solution, so that the microspheres D are fully wetted, and the temperature rise inhibitor of the present invention is obtained. The microspheres D are fully immersed for no less than 5 minutes; The carrier liquid in the magnetic fluid solution is an ester-based substance, such as diester-based diethyl sebate and phthalate, which is neither soluble in paraffin nor miscible with water. This ensures that the paraffin is sealed while also preventing the gas from dissolving and allowing it to escape quickly.

[0007] After drying microsphere D to remove moisture, a mixture containing sodium bicarbonate crystals, phase change particles, and sodium alginate gel is formed inside, with a calcium silicate coating on the outside. After vacuuming and adding a magnetic fluid solution, the magnetic fluid solution penetrates into the structure and fills the gaps.

[0008] Furthermore, the present invention provides a concrete temperature rise inhibitor prepared by the above method.

[0009] Furthermore, the present invention also provides a method for using the above-mentioned concrete temperature rise inhibitor: during use, the large volume of concrete is divided into three equal parts: upper, middle and lower; wherein, the lower and upper parts are treated with temperature rise inhibitor II, and the middle part is treated with temperature rise inhibitor I. Among them, the temperature rise inhibitor I is a concrete temperature rise inhibitor prepared by selecting paraffin as phase change particles; The temperature rise inhibitor II is a concrete temperature rise inhibitor prepared by selecting lauric acid as the phase change particle. Meanwhile, temperature sensors are installed inside the upper, middle and lower parts of the concrete and connected to an external magnetic field switch. The magnetic induction intensity of the concrete is not less than 0.3T. When the internal temperature exceeds the phase transition temperature of lauric acid, the magnetic field is automatically turned on, controlling the internal magnetic fluid to undergo a morphological transformation from liquid to solid, thus hindering the migration of liquid and ions.

[0010] When the temperature rise inhibitor additive prepared according to this invention is added to concrete, as the internal temperature of the concrete rises to the melting point of the phase change material (PCM), the PCM absorbs heat, melts, and overflows. Under this temperature condition, an internal temperature sensor transmits the temperature to the outer surface in real time. When the external surface confirms that the internal temperature has reached the melting temperature of the PCM, a magnet is placed on the concrete surface to form a magnetic field. At this time, under the action of the magnetic field, the magnetic fluid instantly changes from a liquid state to a non-flowing state. The magnetic fluid inside the additive microspheres blocks the channels and is not miscible with the PCM, preventing the PCM from migrating outward. Meanwhile, a small amount of magnetic fluid on the surface of the additive particles in the concrete is dispersed inside the concrete due to stirring and other processes, and mixed between the slurry. Under the action of the magnetic field, the mixed magnetic fluid forms a solid state and blocks the water migration channels, further preventing the migration of water and ions, thereby delaying the occurrence of the hydration reaction and inhibiting the temperature rise. At the same time, under this temperature condition, sodium bicarbonate inside the microspheres decomposes under endothermic conditions. The endothermic process itself helps to reduce the temperature rise. In addition, the decomposition under endothermic conditions generates carbon dioxide. The carbon dioxide overflows and reacts with calcium ions in the concrete to form calcium carbonate precipitates, which reduce the alkalinity of the solution and the concentration of calcium ions. At the same time, it adheres to the surface of cement hydration products, delaying the occurrence of cement hydration reaction and inhibiting the temperature rise.

[0011] Meanwhile, since the phase change materials of temperature rise suppression components I and II have different compositions and phase change temperatures, the gradient design and zonal layout method is mainly aimed at the characteristics of large-volume concrete sections with huge cross-sections and significant internal and external temperature differences. Temperature rise inhibitors with higher phase change temperatures are placed in the middle region where temperature rise is high, enabling efficient heat absorption within this temperature range and precise control of the maximum temperature rise. Temperature rise inhibitors with lower phase change temperatures are placed in the transition regions on both sides where temperature rise is lower, allowing for earlier initiation of the active heat absorption process in these regions, delaying temperature rise in the transition area, providing sufficient temperature difference for the outward transfer of temperature rise from the middle region, promoting the outward migration of temperature from the middle region, and reducing the overall internal and external temperature difference of the structure. Through this zonal gradient layout, a "multi-layered temperature control defense line" is formed, activated sequentially from the outside to the inside, achieving optimized and intelligent control of the temperature field.

[0012] In summary, by controlling the morphological transformation of magnetofluid under magnetic field conditions, the outflow of phase change material and the migration of water and ions are suppressed, thereby reducing the hydration reaction rate. By melting the phase change material to provide a stable temperature for the decomposition of sodium bicarbonate, the sodium bicarbonate is allowed to dissolve endothermally and produce carbon dioxide, which participates in the reaction, thus suppressing the hydration reaction rate and achieving internal temperature control. By gradient deployment of different temperature rise inhibitors, the temperature field can be optimized and intelligently controlled.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves a reduction in internal temperature rise and stable temperature control through the synergistic effects of magnetic fluid, phase change material phase change, sodium bicarbonate endothermic reaction cooling, and the participation of carbon dioxide, a product of sodium bicarbonate reaction, in the reaction to generate calcium carbonate, which reduces alkali and provides adhesion and coverage. For example, when the concrete temperature decreases, the phase change material solidifies, and the reaction stops when sodium bicarbonate does not reach the reaction temperature. When the temperature rises, the carbon dioxide generated by the decomposition of bicarbonate inhibits the temperature rise, causing the concrete temperature to drop, leading to the solidification of the phase change material and thus inhibiting the decomposition of sodium bicarbonate. This forms a stable self-circulating temperature control process.

[0014] In addition, as an internal dopant, the magnetofluid controls the generation of the external magnetic field by measuring the internal temperature, thereby constraining the reaction and suppressing the temperature rise.

[0015] Finally, by deploying different temperature rise inhibitors in a gradient manner, a stable and effective control of the internal and external temperature difference is achieved, reducing the generation of temperature cracks and improving volume stability. Detailed Implementation

[0016] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 The preparation method of concrete temperature rise inhibitor I in this embodiment includes the following: (1) First, add 20 parts of sodium bicarbonate to 100 parts of water, stir evenly, then add 0.2 parts of sodium alginate, and disperse by ultrasonication to form mixture A; (2) Heat mixture A to 68°C, add paraffin wax with a melting temperature of 64°C, and disperse it evenly by ultrasonic vibration to form mixture B; after the paraffin wax particles are molten in mixture A, disperse them under ultrasonic conditions of 30kHz for 3 minutes to form a mixed emulsion of sodium bicarbonate, sodium alginate and paraffin wax. (3) Droplets of mixture B with a particle size of 2 mm were dropped into a 0.2% calcium chloride solution to form microspheres C. After reacting in the solution for 25 seconds, the microspheres were removed. The temperature of the calcium chloride solution was 28℃. (4) Microsphere C was added to a water glass solution with a modulus of 2 and a concentration of 30%. After reacting for 6 hours, the microsphere particles D were obtained by filtration. (5) After drying the microspheres D, vacuum them and add them to a magnetic fluid solution with phthalic acid diester as the base carrier, so that the microspheres D are fully wetted to form temperature rise inhibitor I.

[0018] The preparation method of concrete temperature rise inhibitor II in this embodiment includes the following: The specific preparation method is the same as above, except that paraffin is replaced with lauric acid with a melting point of 44℃; in step (2), the solution temperature is controlled at 45℃; after drying microspheres D, the moisture is removed, and sodium bicarbonate crystals and lauric acid particles are formed inside, and the outside is a calcium silicate coating layer. After vacuuming and adding it to the magnetic fluid solution, the magnetic fluid solution penetrates into the interior of the structure and fills the gaps.

[0019] Example 2 The preparation method of concrete temperature rise inhibitor I in this embodiment includes the following: (1) First, add 30 parts of sodium bicarbonate to 100 parts of water, stir evenly, then add 0.1 parts of sodium alginate, and disperse by ultrasonication to form mixture A; (2) Heat mixture A to 65°C, add paraffin wax with a melting temperature of 58°C, and disperse it evenly by ultrasonic vibration to form mixture B; After the paraffin particles are molten in mixture A, they are dispersed under ultrasonic conditions of 20 kHz for 5 min to form a mixed emulsion of sodium bicarbonate, sodium alginate and paraffin. (3) Mixture B is dropped into a 0.5% calcium nitrate solution to form microspheres C. After reacting in the solution for 20 seconds, the microspheres are removed. The temperature of the calcium chloride solution is 25℃. (4) Microsphere C was added to a water glass solution with a modulus of 2.5 and a concentration of 20%. After reacting for 8 hours, the microsphere particles D were obtained by filtration. (5) After drying the microspheres D, vacuum them and add them to a magnetic fluid solution with diethyl sebacic acid as the base carrier, so that the microspheres D are fully wetted to form temperature rise inhibitor I.

[0020] The preparation method of concrete temperature rise inhibitor II in this embodiment includes the following: The specific preparation method is the same as above, except that paraffin is replaced with lauric acid with a melting point of 44℃. In step (2), the solution temperature is controlled at 68℃. After drying the microspheres D, the moisture is removed, and sodium bicarbonate crystals and lauric acid particles are formed inside, while the outside is a calcium silicate coating layer. After vacuuming and adding the magnetic fluid solution, the magnetic fluid solution penetrates into the interior of the structure and fills the gaps.

[0021] Example 3 The preparation method of concrete temperature rise inhibitor I in this embodiment includes the following: (1) First, add 28 parts of sodium bicarbonate to 100 parts of water, stir evenly, then add 0.12 parts of sodium alginate, and disperse by ultrasonication to form mixture A; (2) Heat mixture A to 66°C, add paraffin wax with a melting temperature of 62°C, and disperse it evenly by ultrasonic vibration to form mixture B; After the paraffin particles are molten in mixture A, they are dispersed under ultrasonic conditions of 25 kHz for 4 min to form a mixed emulsion of sodium bicarbonate, sodium alginate and paraffin. (3) Droplets of mixture B with a diameter of 0.5 mm are dropped into calcium bicarbonate with a concentration of 0.4% to form microspheres C. After reacting in the solution for 24 seconds, the microspheres are removed. The temperature of calcium chloride is 25℃. (4) Microsphere C was added to a water glass solution with a modulus of 2.4 and a concentration of 25%. After reacting for 7 hours, the microsphere particles D were obtained by filtration. (5) After drying the microspheres D, vacuum them and add them to a magnetic fluid solution with phthalic acid diester as the base carrier, so that the microspheres D are fully wetted to form temperature rise inhibitor I.

[0022] The preparation method of concrete temperature rise inhibitor II in this embodiment includes the following: The specific preparation method is the same as above, except that paraffin is replaced with lauric acid with a melting point of 44℃. In step (2), the solution temperature is controlled at 48℃. After drying the microspheres D, the moisture is removed, and sodium bicarbonate crystals and lauric acid particles are formed inside, while the outside is a calcium silicate coating layer. After vacuuming and adding the magnetic fluid solution, the magnetic fluid solution penetrates into the interior of the structure and fills the gaps.

[0023] Comparative Example 1 The difference from Example 3 is that the amount of sodium bicarbonate used is 10 parts.

[0024] Comparative Example 2 The difference from Example 3 is that the amount of sodium bicarbonate used is 40 parts.

[0025] Comparative Example 3 The difference from Example 3 is that the sodium alginate concentration is 0.01%.

[0026] Comparative Example 4 The difference from Example 3 is that the sodium alginate concentration is 0.5%.

[0027] Comparative Example 5 The difference from Example 3 is that no magnetic fluid is added.

[0028] Comparative Example 6 The difference from Example 3 is that the magnetofluid-based carrier liquid is water.

[0029] Comparative Example 7 Only the temperature rise inhibitor I from Example 3 was used.

[0030] Comparative Example 8 Only the temperature rise inhibitor II from Example 3 was used.

[0031] Comparative Example 9 The difference from Example 3 is that only an equal amount of paraffin is added as a phase change material.

[0032] The standard concrete mix proportion is as follows: ordinary Portland cement P.O42.5 dosage is 300 kg / m³. 3 The fly ash usage is 100 kg / m³ 3 The sand content is 42%, the sand is river sand with a fineness modulus of 2.8, the aggregate is 5-20mm continuously graded crushed stone, the water-cement ratio is 0.42, the admixture is polycarboxylate superplasticizer with a water reduction rate of 29%, and the dosage is 1.5% of the cement content. The concrete density is 2380 kg / m³. 3 The aforementioned temperature rise inhibitor was incorporated into the concrete at a dosage of 2% of the cement content. A large-volume concrete structure with dimensions of 1.5 × 1.5 × 1.5 m was prepared and poured in three stages from bottom to top. Temperature rise inhibitor II was used for the upper and lower sections, while temperature rise inhibitor I was used for the middle section, with consistent dosages. Each pour was 0.5 m thick. The peak temperature rise and 28-day compressive strength of the concrete were measured, as shown in Table 1. The 28-day compressive strength was calculated by averaging three 100 × 100 × 100 mm blocks cut from the middle of the upper, middle, and lower sections.

[0033] Table 1 Concrete Properties Comparing Comparative Example 1, Comparative Example 2, and Example 3, it can be seen that the temperature rise inhibition effect is weakened in Comparative Example 1. The temperature rise inhibition effect is significant in Comparative Example 2, but the strength decreases. This is because the main purpose of sodium bicarbonate is to ensure that it undergoes endothermic decomposition to produce carbon dioxide when used in concrete due to the rising temperature of the concrete. When the sodium bicarbonate content is low, the heat absorption is less, and the carbon dioxide generated in the later reaction is insufficient. This results in less calcium carbonate formation from the reaction with calcium hydroxide in the concrete, weaker adhesion to cement particles and hydration products, and a reduced effect on temperature rise control. Higher content leads to a faster reaction, excessive adhesion, and impaired normal cement hydration, resulting in decreased strength.

[0034] Comparing Comparative Examples 3, 4, and 3, it can be seen that the temperature rise inhibition effect is weakened in Comparative Example 3, and the strength decreases significantly. In Comparative Example 4, the strength decreases slightly, and the temperature rise inhibition effect is slightly weakened. This is because the concentration of sodium alginate is controlled to regulate the number and area of ​​surface pores in the later-formed calcium alginate microspheres. If the sodium alginate concentration is too low, the calcium alginate microsphere coating on the surface of the formed calcium alginate microspheres is thin, resulting in a thin calcium silicate shell that is easily damaged during stirring, affecting the performance. Higher concentrations result in higher calcium alginate density and fewer pores on the surface of the calcium alginate microspheres, leading to fewer pores when forming the calcium silicate shell later. This makes magnetic fluid penetration difficult, weakens the resistance to the phase change of paraffin into liquid, and the dissolution of the phase change liquid affects cement hydration, leading to a decrease in strength. Simultaneously, excessively high concentrations result in excessively high solution viscosity, which is unfavorable for preparation.

[0035] Comparing Comparative Example 5 and Example 3, it can be seen that the temperature rise inhibition effect is weakened, and the strength decreases. This is because the incorporation of magnetic fluid is intended to cause the magnetic fluid to instantly change from a liquid to a non-fluid state under the influence of an external magnetic field. The magnetic fluid inside the additive microspheres blocks the channels and is immiscible with paraffin, preventing the paraffin from migrating outward. Meanwhile, the magnetic fluid incorporated between the surface of the additive particles and the slurry within the concrete blocks the water migration channels, further preventing ion migration, thereby delaying the hydration reaction and inhibiting temperature rise. When magnetic fluid is lacking, the flow of the phase change material liquid into the concrete cannot be controlled under high-temperature conditions, affecting the continuity of hydration products and causing a decrease in strength.

[0036] Comparing Comparative Example 6 and Example 3, it can be seen that the temperature rise inhibition effect is weakened, and the temperature rise is promoted, resulting in a decrease in strength. This is because when the carrier fluid of the magnetic fluid is water, it can fuse with the moisture in the concrete, causing a large amount of magnetic fluid to migrate into the concrete interior. The magnetic fluid is mainly composed of nano-sized particles; when dispersed within the concrete, it forms crystal nuclei, which in turn promotes cement hydration, leading to accelerated early hydration and a faster temperature rise. Simultaneously, this results in weak later strength growth and relatively low strength.

[0037] Comparing Comparative Example 7 and Example 3, it can be seen that the temperature rise suppression effect is weakened. Furthermore, it can be observed that among the upper, middle, and lower parts, only the middle part shows effective temperature rise suppression, and the temperature increases somewhat, while the temperature rise control on the sides is not significant. This is because the core area of ​​the concrete core generally has difficulty dissipating heat and has the highest temperature. When the core area of ​​the middle part has the highest temperature, it is necessary to ensure sufficient heat dissipation channels on the upper and lower sides; that is, the lower the temperature, the better for heat dissipation. Therefore, when the upper and lower sides use a material that undergoes a phase change at low temperatures as the core material for the phase change, it is beneficial to control the temperature rise measured at the top and bottom, thereby increasing the temperature difference between the upper and lower sides and the middle part, thus accelerating the outward transfer of temperature from the middle part and reducing the peak temperature rise of the core. When the upper and lower sides use the same temperature rise material as the core part, their phase change temperatures are consistent. Usually, when the temperature in the middle reaches the phase change temperature, the temperature in the upper and lower parts has not yet reached the phase change temperature, thus failing to exert a good temperature rise suppression effect, and therefore the temperature rise suppression effect is limited.

[0038] A comparison of Comparative Example 8 and Example 3 shows a significant decrease in strength. This is because the phase transition at excessively low temperatures restricts the continued hydration reaction in the middle part of the concrete, affecting the normal hydration of cement. Therefore, although it inhibits temperature rise, it leads to a decrease in final strength.

[0039] Comparing Comparative Example 9 and Example 3, it can be seen that when only paraffin is added as a phase change material, the temperature rise control of the concrete is weak, and the strength decreases significantly. This is mainly because the heat absorption effect of paraffin alone is limited. When its dosage is controlled, its temperature rise control effect is limited. At the same time, after the addition of paraffin, it can adhere to the surface of cement particles, hindering cement hydration and affecting the formation of a continuous network structure of hydration products, resulting in a significant reduction in strength.

Claims

1. A method for producing a concrete temperature rise inhibitor, characterized by, Comprising the following steps: (1) First, sodium bicarbonate is added to water, and after stirring evenly, sodium alginate is added, and a mixed solution A is formed by ultrasonic dispersion; (2) The mixed solution A obtained in step (1) is warmed, and phase change particles are added, and after ultrasonic dispersion, a mixed emulsion B is formed; The phase change particles are paraffin or lauric acid, wherein the phase change temperature of paraffin is 58~64℃, and the phase change temperature of lauric acid is 42~46℃, and the warming temperature range of the mixed solution A is the highest melting point of the selected phase change particles+1℃~64℃; (3) The mixed emulsion B obtained in step (2) is dropped into an excess of calcium salt solution, and microspheres C are formed after reacting for 20~25s; The mass concentration of the calcium salt solution is 0.2~0.5%; The mixed emulsion B is formed into particles with a diameter not greater than 2mm, which are dropped into the calcium salt solution; (4) The microspheres C fished from the solution after the reaction in step (3) are added to an excess of water glass solution, reacted, filtered, and microsphere particles D are obtained; The modulus of the water glass is 2~2.5, and the mass concentration of the solution is 20~30%; (5) After the microspheres D obtained in step (4) are dried to remove water, they are vacuumed and added to an excess of magnetic fluid solution, so that the microspheres D are fully infiltrated, and the temperature rise inhibitor is obtained; The fully infiltrated time of the microspheres D is not less than 5min.

2. The method of claim 1, wherein, The mass fractions of the raw materials in steps (1) and (2) are as follows: Sodium bicarbonate 20~30 parts, Sodium alginate 0.1~0.2 parts, Water 100 parts, Phase change particles 30~40 parts.

3. The preparation method according to claim 1, characterized in that, The ultrasonic frequency in step (1) is 20~25kHz, and the ultrasonic dispersion time is 8~12min; The ultrasonic frequency in step (2) is 20~30kHz, and the ultrasonic dispersion time is 3~5min.

4. The preparation method according to claim 1, characterized in that, The calcium salt in step (3) is selected from any one of calcium chloride, calcium nitrate, and calcium bicarbonate; The temperature of the calcium salt solution is normal temperature, which is below 30℃.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The specific method for dropping the mixed emulsion B into the excess of calcium salt solution in step (3) is as follows: the mixed emulsion B is added to a needle cylinder, the needle hole diameter is not greater than 1mm, the mixed emulsion B is extruded along the vertical direction from top to bottom through the needle hole outlet, and liquid droplets not greater than 2mm are formed during the falling process in the air, and are dropped into the excess of calcium salt solution; The needle hole is one or more.

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The reaction time in step (4) is 6~8h.

7. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The base carrier liquid in the magnetic fluid solution in step (5) is an ester-based substance.

8. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The base carrier liquid in the magnetic fluid solution is diethyl succinate or phthalate diester.

9. A concrete temperature rise inhibitor prepared by the method of any one of claims 1 to 8.

10. A method of using the concrete temperature rise inhibitor of claim 9, wherein, Comprising: In use, the mass concrete is divided into upper, middle and lower parts on average; wherein the lower part and the upper part use the temperature rise inhibitor II, and the middle part uses the temperature rise inhibitor I; The temperature rise inhibitor I is a concrete temperature rise inhibitor prepared by selecting paraffin as the phase change particles; The temperature rise inhibitor II is a concrete temperature rise inhibitor prepared by selecting lauric acid as the phase change particles; Meanwhile, temperature sensors are arranged in the middle, upper and lower parts of the concrete, and are connected with the external magnetic field switch, and the magnetic induction intensity of the concrete is not less than 0.3T.

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