Anti-corrosion sacrifice concrete and preparation method thereof

Abstract

The invention provides anti-corrosion sacrificial concrete and a preparation method thereof. The anti-corrosion sacrifice concrete is prepared from the following components in parts by weight: 300 to 400 parts of cement, 30 to 50 parts of barium ferrite, 100 to 150 parts of fly ash, 10 to 50 parts of silica fume, 350 to 900 parts of quartz sand, 700 to 900 parts of hematite iron ore, 300 to 1300 parts of steel grit, 3 to 8 parts of polypropylene fiber, 210 to 230 parts of water and 3 to 9 parts of a water reducing agent. The preparation method comprises the following steps: sequentially mixing and stirring the raw materials, pouring, forming and curing. The sacrificial concrete disclosed by the invention has the synergistic advantages of high crack resistance and impermeability, and the corrosion rate of the aluminoferrite cement-based sacrificial concrete under extreme thermochemical erosion is fundamentally reduced; the doping of the steel grit leads to the formation of a discontinuous metal ceramic barrier layer in the holes of the sacrificial concrete at high temperature, so that the corrosion permeation rate of the sacrificial concrete is obviously reduced.

Description

Technical Field

[0001] This application relates to the field of special concrete technology, and in particular to an anti-erosion sacrificial concrete and its preparation method. Background Technology

[0002] Nuclear power, as a highly efficient and low-carbon clean energy source, is of strategic significance for optimizing the energy structure. However, under extreme operating conditions at nuclear power plants, core meltdown can trigger catastrophic radioactive leaks, causing long-term harm to society and the environment. To address such over-design-baseline accidents, third-generation nuclear power technologies generally employ core traps to retain molten material. Sacrificial concrete is a key component in this process, absorbing heat through its own melting and decomposition to cool and solidify the high-temperature molten material. However, when the molten core material (temperatures exceeding 3000°C) continues to erode the structure, existing conventional third-generation sacrificial concrete, due to insufficient high-temperature stability, is prone to dehydration and decomposition of cementitious materials and aggregates, leading to structural collapse. This can result in a violent melting reaction, causing the molten material to penetrate the core trap and erode the containment floor, causing barrier failure and radioactive material leakage.

[0003] Current research on sacrificial concrete focuses on optimizing its thermal properties (such as endothermic enthalpy and gasification rate) to enhance the cooling and solidification of the molten material. However, systematic research on its resistance to erosion under high-temperature erosion environments is lacking. In traditional sacrificial concrete formulations, ordinary cement and calcareous aggregates (such as limestone) readily undergo violent thermochemical erosion reactions with the molten material, resulting in excessively rapid and uncontrollable erosion rates, which weakens the long-term retention capacity of core traps. Therefore, there is an urgent need to develop a novel sacrificial concrete material and preparation method optimized for erosion performance to address the core deficiency of existing technologies in their insufficient resistance to erosion under high-flux thermal shock. Summary of the Invention

[0004] The purpose of this application is to provide erosion-resistant sacrificial concrete and its preparation method to solve or alleviate the problems existing in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: A sacrificial concrete resistant to erosion comprises the following components in parts by weight: 300-400 parts cement, 30-50 parts barium ferrite, 100-150 parts fly ash, 10-50 parts silica fume, 350-900 parts quartz sand, 700-900 parts hematite, 300-1300 parts steel grit, 3-8 parts polypropylene fiber, 210-230 parts water, and 3-9 parts water-reducing agent.

[0006] Preferably, the erosion-resistant sacrificial concrete comprises the following components in parts by weight: The composition includes 348.02 parts of aluminoferrite cement, 138.11 parts of fly ash, 27.62 parts of silica fume, 379.17 parts of quartz sand, 796.23 parts of hematite, 38.67 parts of barium ferrite, 1270.08 parts of steel grit, 4.91 parts of polypropylene fiber, 220.97 parts of water, and 5.52 parts of water-reducing agent.

[0007] The raw materials used in this application, including fly ash, silica fume, quartz sand, hematite, and water-reducing agent, are conventional components of concrete. This application uses aluminoferrite cement to replace silicate cement in conventional sacrificial concrete. In nuclear power scenarios, the aluminoferrite cement, the ferric oxide in barium ferrite, and the silica in quartz sand preferentially react with the active reducing agents zirconium and uranium metal in the reactor core melt to form zirconium dioxide and uranium dioxide, exhibiting significant sacrificial properties, and the reaction process does not produce hydrogen.

[0008] Furthermore, the steel shot is continuously graded, with a particle size of 0-4 mm and a density of 6000-8000 kg / m³. 3 The steel shot contains not less than 90% Fe and the impurities contain not more than 0.05% S and not more than 0.05% P.

[0009] Furthermore, the steel shot contains at least 40% particles with a diameter of 1-2 mm; the steel shot is spherical with a hardness of 30-60 HRC and a surface roughness Rz of 10-150 μm. Through the endothermic solid-liquid phase transition and high-temperature alloying reaction of high-purity Fe, the steel shot provides sacrificial concrete with resistance to erosion. This is because: 1) The steel shot undergoes a solid-liquid phase transition in the 1200-1400℃ range (latent heat of fusion 272 J / g), absorbing more than three times the heat of the molten material compared to traditional aggregates, significantly reducing the temperature of the molten material and inhibiting its thermochemical erosion of the sacrificial concrete matrix. 2) Molten Fe undergoes in-situ alloying with UO2 / ZrO2 in the core melt, forming a high-melting-point (U,Zr,Fe)O2 solid solution with a melting point >1800℃. This solid solution can construct a discontinuous metal-ceramic barrier layer within the pores of the sacrificial concrete, effectively blocking further penetration of the erosion process and thus significantly reducing the erosion penetration rate of the sacrificial concrete. The formation of high-melting-point (U, Zr, Fe)O2 solid solutions has been confirmed in existing studies of severe nuclear reactor accidents. The core melt (containing UO2, ZrO2, Zr metal, etc.) alloys in situ with the structural steel at the accident site, forming a Fe-Zr-UO composite phase. Figure 1 and Figure 5As can be seen, at room temperature, the spherical steel grit particles are tightly wrapped by the hydration products of the cementitious material. However, after being subjected to a high temperature of 1000℃, the matrix of the corrosion-resistant sacrificial concrete decomposes, causing its structure to fail, and the originally wrapped steel grit disperses. Furthermore, the cement is 42.5 aluminoferrite cement with a particle size range of 0-100μm, an initial setting time of not less than 30min, and a specific surface area greater than 370m². 2 / kg, bulk density is 1300-1600kg / m³ 3 The Fe2O3 content is greater than 6%, and the 28-day compressive strength is greater than 45 MPa. Ferroaluminate cement, whose hydration products are mainly low-alkaline calcium sulfoaluminate, can form a denser microstructure, thus significantly improving the anti-melting performance of sacrificial concrete. Compared with traditional silicate cement, ferroaluminate cement-based concrete effectively avoids cracks caused by thermal stress, blocking the rapid penetration channels of molten core material along cracks; at the same time, it greatly slows down the penetration depth and reaction rate of the molten material, providing a longer protection window for the integrity of the containment structure.

[0010] Furthermore, the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent, which is colorless to light yellow in appearance, has a density of 1.05-1.15 g / ml, a solid content of ≥40% by mass fraction, an air content of 6%-8% by volume fraction, a pH value of 4±2, and a water reduction rate of ≥30%.

[0011] Furthermore, the fly ash is Class I fly ash with a particle size range of 0-100 μm and a specific surface area greater than 400 m². 2 / kg, bulk density is 900-1300kg / m³ 3 The specific surface area of ​​the silica fume is greater than 15000 m². 2 / kg, with an average particle size of 0.1-0.3μm, of which particles smaller than 0.1μm account for more than 80%. Fly ash and silica fume are active admixtures.

[0012] Furthermore, the quartz sand described is high-quality quartz sand with a SiO2 content greater than 99%; the mass fraction of quartz sand with a particle size of 0mm-4mm is 56%, and the mass fraction of quartz sand with a particle size of 4mm-8mm is 44%.

[0013] Furthermore, the hematite is high-quality hematite with an Fe2O3 content of ≥90%; the mass fraction of hematite with a particle size of 0mm-4mm is 56%, and the mass fraction of hematite with a particle size of 4mm-8mm is 44%.

[0014] Furthermore, the barium ferrite contains more than 12 wt% BaO and more than 83 wt% Fe2O3, and the particle size range of the barium ferrite is 1-100 μm, wherein the proportion of particles with a particle size of less than 50 μm is greater than 80%.

[0015] Furthermore, the polypropylene fibers have a length of 10-15 mm, a diameter of 20-50 μm, and a density of not less than 910 kg / m³. 3 The elastic modulus is not less than 3500 MPa, and the elongation at break is 15%-30%. Polypropylene fibers not only improve the early crack resistance of concrete but also enhance the high-temperature burst resistance of erosion-resistant sacrificial concrete: 1) Firstly, polypropylene fibers effectively inhibit the propagation of microcracks and delay the appearance of large cracks. 2) Secondly, polypropylene fibers improve the interfacial transition zone structure of erosion-resistant sacrificial concrete, making it denser, thereby reducing matrix porosity and optimizing pore structure. When the temperature rises to the melting point of polypropylene fibers (approximately 164℃-170℃), the fibers shrink and deform. After the temperature exceeds the melting point, the fibers completely melt, forming numerous micropores and interconnected channels in situ. This process not only increases the porosity of the material, but more importantly, these channels effectively connect the microcracks generated by thermal expansion, constructing a connected crack-pore network. This network provides an efficient diffusion path for water vapor generated at high temperatures, thereby effectively releasing internal steam pressure and preventing concrete bursting caused by pressure buildup. Figures 2 to 5 The images show scanning electron microscope (SEM) images of the sacrificial concrete of this invention at different temperatures. As can be seen from the images, at 25°C, the polypropylene fibers maintain their original morphology; when the temperature reaches 200°C, the fibers significantly shrink and deform, eventually melting to form a clear channel structure and generate microcracks in the radial direction. As the temperature increases, the number of microcracks gradually increases. These changes in microstructure confirm the mechanism by which the fibers significantly improve the material's resistance to bursting by creating pores through melting and connecting cracks.

[0016] This invention also proposes a method for preparing the aforementioned erosion-resistant sacrificial concrete, comprising the following steps: Step 1: Mix aluminoferrite cement, fly ash, silica fume, and barium ferrite in a container at a speed of 40-50 rpm for 15-20 minutes to obtain mixture M1; Step 2: Add quartz sand, hematite, and steel shot to the above mixture M1, and stir at a speed of 40-50 rpm for 15-20 minutes to obtain mixture M2; Step 3: Mix a portion of water with the water-reducing agent and add it to the above mixture M2. Stir at 40-50 rpm for 15-20 minutes to obtain mixture M3. Step 4: After rinsing each container with the remaining water, add it to the above mixture M3 and stir at a speed of 40-50 rpm for 8-15 minutes to obtain mixture M4; Step 5: Add polypropylene fibers to the above mixture M4 and continue stirring at 40-50 rpm for 8-15 minutes to obtain erosion-resistant sacrificial concrete. Then, mold and cure the erosion-resistant sacrificial concrete. The preparation method of the erosion-resistant sacrificial concrete aims to ensure that the raw materials of the sacrificial concrete are fully mixed and uniformly distributed in the matrix, thereby improving the consistency of the mechanical properties of the composite material. The stirring time and speed given above can be adjusted according to actual conditions and personal experience. This preparation process is simple and can be produced using a conventional forced concrete mixer.

[0017] Compared with conventional sacrificial concrete, the technical solution of this application has the following advantages: Compared to conventional sacrificial concrete using quartz sand or hematite aggregates, this application employs a composite aggregate system composed of steel grit, quartz sand, and hematite. The steel grit, through the endothermic solid-liquid phase transition of high-purity Fe and high-temperature alloying reaction, enhances the erosion resistance of the sacrificial concrete. The steel grit is continuously graded within 0-4mm, while the quartz sand and hematite are graded in two sizes: 0-4mm and 4-8mm. This combination of three aggregates reduces hydrogen production in the reactor during severe nuclear accidents, enhances the endothermic capacity of the sacrificial concrete, improves the solidification of the molten core, and significantly improves its erosion resistance, thereby ensuring the safety of the nuclear power plant in the event of a severe nuclear accident.

[0018] This application utilizes aluminoferrite cement, which, compared to silicate cement, increases the crack resistance of sacrificial concrete by over 50%, thus preventing accelerated core melt penetration due to thermal shock cracks. Compared to silicate cement, aluminoferrite cement also increases the impermeability of sacrificial concrete by more than two times, significantly slowing down the penetration depth and reaction rate of core melt, providing a longer structural integrity protection window for the containment. Its high crack resistance and impermeability fundamentally reduce the melting rate of aluminoferrite cement-based sacrificial concrete under extreme thermochemical erosion.

[0019] The sacrificial concrete of this invention, containing aluminoferrate cement, hematite, ferric oxide in barium ferrite, and silica in quartz sand, preferentially reacts with the active reducing agents zirconium and uranium metal in the molten core during core meltdown, forming zirconium dioxide and uranium dioxide. This prevents the reaction of metallic zirconium and uranium with water to produce hydrogen. Simultaneously, the free water content of the hardened sacrificial concrete is less than 5%, reducing hydrogen production during the interaction between the molten core and water in the sacrificial concrete, thus increasing safety redundancy during nuclear accidents. It also enhances the erosion resistance of the sacrificial concrete, extending the structural integrity window under molten material erosion and providing crucial redundancy time for accident mitigation measures. Furthermore, its application can be expanded to extreme industrial scenarios such as the lining of high-temperature metallurgical vessels, significantly enhancing the structural durability of nuclear power plants and high-temperature facilities under extreme conditions. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a scanning electron microscope image of the interface transition zone in the erosion-resistant sacrificial concrete of Embodiment 4 of the present invention at 25°C.

[0021] Figure 2 This is a scanning electron microscope image of polypropylene fibers in the erosion-resistant sacrificial concrete of Example 4 of the present invention at 25°C.

[0022] Figure 3 This is a scanning electron microscope image of polypropylene fibers in the erosion-resistant sacrificial concrete of Example 4 of the present invention at 200°C.

[0023] Figure 4 This is a scanning electron microscope image of the polypropylene fibers of the erosion-resistant sacrificial concrete of Example 4 of the present invention at 600°C.

[0024] Figure 5 This is a scanning electron microscope image of the corrosion-resistant sacrificial concrete of Embodiment 4 of the present invention at 1000°C. Detailed Implementation

[0025] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] The raw materials used in the examples are: The cement is grade 42.5 aluminoferrite cement with a specific surface area of ​​386.7 m². 2 / kg, 28d compressive strength is 52.6MPa, Fe2O3 content is 7.95%.

[0027] The fly ash is Class I fly ash, and its density, as tested, is 2100 kg / m³.3 The bulk density is 1.10 kg / m³. 3 The loss on ignition was 2.62%, and the particle size ranged from 0 to 100 μm.

[0028] The specific surface area of ​​the silica fume was measured to be 25,000 m². 2 / kg, with an average particle size of 0.12μm, and the SiO2 mass fraction in the silica ash is 97.49%.

[0029] The quartz sand was tested and found to have a SiO2 content of 99.49%. Two particle sizes, 0-4mm and 4-8mm, were designed for use based on a mass ratio of 14:11.

[0030] The hematite was tested and found to have an Fe2O3 content of 94.60%. Two particle sizes, 0-4mm and 4-8mm, were designed for use based on a mass ratio of 14:11.

[0031] The barium ferrite contained 14.70% BaO and 84.30% Fe2O3, with a particle size range of 1-100 μm, and was purchased from Guangzhou Meizhou Magnetic Materials Co., Ltd.

[0032] The iron content in steel shot is 93%, and its density is 7000 kg / m³. 3 The particle size range is 0-4mm continuous gradation, purchased from Henan Lizhixing Metallurgical Materials Co., Ltd. Other components are: C content 1.18%, Si content 0.45%, S content 0.045%, P content 0.04%. Its hardness is 47HRC, and the surface is spherical.

[0033] Polypropylene fibers have a diameter range of 10-15 mm and a length of 12 mm. They have a circular cross-section, a melting point of 150-176℃, an elastic modulus of 3800 MPa, and an elongation at break of 25%.

[0034] The polycarboxylate superplasticizer has a density of 1.1 g / mL, a solid content of 41.2%, a pH value of 6.8, a water reduction rate of 33.9%, and an air content of 6.5%. It is manufactured by Jiangsu Subote New Material Co., Ltd. and is designated as model PCA-I.

[0035] The water is tap water or drinking water, and meets the requirements of the "Standard for Water Used in Concrete" (JGJ63-2006).

[0036] Example 1 An anti-erosion sacrificial concrete, comprising the following components by weight: 348.02 parts cement, 138.11 parts fly ash, 27.62 parts silica fume, 361.94 parts 0mm-4mm quartz sand, 379.17 parts 4mm-8mm quartz sand, 796.23 parts hematite, 38.67 parts barium ferrite, 317.52 parts steel grit, 4.91 parts polypropylene fiber, 220.97 parts water, and 5.52 parts water-reducing agent.

[0037] The above-mentioned method for preparing erosion-resistant sacrificial concrete includes the following steps: (1) Pour cement, fly ash, silica fume and barium ferrite into a concrete mixer, rotate at 45 rpm, and mix for 15 minutes to obtain mixture M1; (2) Add quartz sand, hematite, and steel shot to the above mixture M1 and stir for 15 minutes to obtain the mixture M2. (3) Mix about three-quarters of the water with the water-reducing agent, add it to the above mixture M2, and stir for 15 minutes to obtain mixture M3; (4) After rinsing each container with the remaining water, add it to the above mixture M3 and stir for 10 minutes to obtain mixture M4; (5) Add polypropylene fiber to the above mixture M4 and stir for 10 minutes to obtain anti-corrosion sacrificial concrete. The anti-corrosion sacrificial concrete can then be molded and cured.

[0038] Example 2 Compared with Example 1, Example 2 differs in the amount of quartz sand and steel grit used in the raw materials of the erosion-resistant sacrificial concrete; the mass of steel grit is twice that in Example 1. The preparation method of the erosion-resistant sacrificial concrete is the same as in Example 1.

[0039] An anti-erosion sacrificial concrete, comprising the following components by weight: 348.02 parts cement, 138.11 parts fly ash, 27.62 parts silica fume, 241.30 parts 0mm-4mm quartz sand, 379.17 parts 4mm-8mm quartz sand, 796.23 parts hematite, 38.67 parts barium ferrite, 635.04 parts steel grit, 4.91 parts polypropylene fiber, 220.97 parts water, and 5.52 parts water-reducing agent.

[0040] Example 3 Compared with Example 1, Example 3 differs in the amount of quartz sand and steel grit used in the raw materials of the erosion-resistant sacrificial concrete; the mass of steel grit is three times that in Example 1. The preparation method of the erosion-resistant sacrificial concrete is the same as in Example 1.

[0041] An anti-erosion sacrificial concrete, comprising the following components by weight: 348.02 parts cement, 138.11 parts fly ash, 27.62 parts silica fume, 120.65 parts 0mm-4mm quartz sand, 379.17 parts 4mm-8mm quartz sand, 796.23 parts hematite, 38.67 parts barium ferrite, 952.56 parts steel grit, 4.91 parts polypropylene fiber, 220.97 parts water, and 5.52 parts water-reducing agent.

[0042] Example 4 Compared with Example 1, Example 4 differs in the amount of quartz sand and steel grit used in the raw materials of the erosion-resistant sacrificial concrete; the mass of steel grit is four times that in Example 1. The preparation method of the erosion-resistant sacrificial concrete is the same as in Example 1.

[0043] An anti-erosion sacrificial concrete, comprising the following components by weight: 348.02 parts cement, 138.11 parts fly ash, 27.62 parts silica fume, 379.17 parts 4mm-8mm quartz sand, 796.23 parts hematite, 38.67 parts barium ferrite, 1270.08 parts steel grit, 4.91 parts polypropylene fiber, 220.97 parts water, and 5.52 parts water-reducing agent.

[0044] Comparative Example 1 Compared to Example 1, Comparative Example 1 does not contain steel shot and uses an equal mass of 0mm-4mm quartz sand instead. The method for preparing the sacrificial concrete is the same as in Example 1.

[0045] A sacrificial concrete, by weight, comprises the following components: 348.02 parts cement, 138.11 parts fly ash, 27.62 parts silica fume, 482.59 parts 0mm-4mm quartz sand, 379.17 parts 4mm-8mm quartz sand, 796.23 parts hematite, 38.67 parts barium ferrite, 4.91 parts polypropylene fiber, 220.97 parts water, and 5.52 parts water-reducing agent.

[0046] Performance testing was performed on the examples and comparative examples: Density test: according to the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" (GB / T50080-2016); 28-day compressive strength: The 28-day axial compressive strength of the erosion-resistant sacrificial concrete in the above examples and comparative examples was measured according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T50081-2019). 28-day chloride ion migration coefficient test: According to the "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009), the 28-day chloride ion migration coefficient was tested using a CABR-RCM chloride ion diffusion coefficient tester. Thermal analysis: The silicon-iron sacrificial mortar was thermally analyzed using a NETZSCH STA 449 F5 synchronous thermal analyzer (NETZSCH GmbH, Germany) at a test temperature of 1200℃.

[0047] Composition analysis: X-ray fluorescence spectrometry was used to analyze the chemical composition of the anti-erosion sacrificial concrete to obtain the contents of the main components SiO2 and Fe2O3.

[0048] Table 1. Performance test results of the anti-melting sacrificial concrete obtained in Examples 1-4

[0049] From Example 1 to Example 4, the amount of steel shot gradually increased from 317.52 parts by weight to 1270.08 parts by weight, with an increase of 317.52 parts per grade. Correspondingly, the mass of 0mm-4mm quartz sand gradually decreased from 361.94 parts to 0 parts. In Comparative Example 1, steel shot was not used and was replaced with the same mass of 0mm-4mm quartz sand to keep the total mass of aggregate consistent.

[0050] As can be seen from Table 1, in the four embodiments, since the density of steel shot is greater than that of quartz sand, the density of the anti-corrosion sacrificial concrete gradually increases with the increase of steel shot content. Compared with the comparative example, the density of the embodiments increased by 7.89%, 15.58%, 23.57%, and 31.73%, respectively.

[0051] In all embodiments and comparative examples, the compressive strength of the erosion-resistant sacrificial concrete was greater than 30 MPa, which met the strength requirements of sacrificial concrete. As the amount of steel grit increased, the compressive strength increased because the high density and rigidity of the steel grit enhanced the support of the aggregate skeleton.

[0052] In all embodiments and comparative examples, the chloride ion migration coefficient of the corrosion-resistant sacrificial concrete was less than 5 × 10⁻⁶. -12 The steel shot has a density of m² / s, which is better than ordinary silicate cement in resisting chloride ion diffusion. Comparative Example 1 has the worst impermeability because the dense packing and increased density of steel shot reduces the channels for chloride ion penetration.

[0053] According to heat transfer theory, the erosion rate of sacrificial concrete is related to the heat flux transferred into it by the formula V = Q / (ρ × A × ΔH), where V is the erosion rate of the sacrificial concrete, Q is the heat flux transferred into the sacrificial concrete, ρ is the density of the sacrificial concrete, A is the erosion area of ​​the sacrificial concrete, and ΔH is the decomposition enthalpy change of the sacrificial concrete. This indicates that the erosion rate of sacrificial concrete is inversely proportional to its density and decomposition enthalpy change. Therefore, increasing the density and decomposition enthalpy change of the sacrificial concrete leads to a decrease in its erosion rate.

[0054] In the four embodiments, the enthalpy change of the erosion-resistant sacrificial concrete increased with the increase of steel grit replacement rate, meaning that the unit mass of concrete can absorb more heat from the molten material, which can accelerate the cooling of the core molten material and reduce its fluidity. This indicates that the erosion rate of the erosion-resistant sacrificial concrete gradually decreases, thereby improving the safety of the nuclear power plant. This is because the Fe content in the steel grit is ≥90%, and the high Fe component significantly improves the heat absorption efficiency of the concrete. Compared with the comparative example, the erosion rates of the embodiments decreased by 16.21%, 28.81%, 39.10%, and 45.76%, respectively.

[0055] All the sacrificial concretes in the examples and comparative examples contained high levels of SiO2 and Fe2O3, enabling them to react with the core melt and exhibiting significant sacrificial properties. The content of SiO2 and Fe2O3 showed a clear correlation with the amount of quartz sand or steel shot in the raw materials; a higher amount of steel shot resulted in a higher Fe2O3 content in the sacrificial concrete. Compared to SiO2, Fe2O3, due to its combined reaction with the melt and high endothermic properties, contributed more to reducing the erosion rate of the sacrificial concrete. Therefore, Example 4 was the optimal example. It should be noted that although a higher amount of steel shot contributes to the erosion resistance of the sacrificial concrete, the total mass per unit volume of the sacrificial concrete is fixed. Therefore, steel slag (for each raw material) should not be used excessively, as excessive use will affect the workability and other properties of the concrete.

[0056] In summary, the compressive strength of the erosion-resistant sacrificial concrete prepared by this invention is higher than 30 MPa, which meets the basic strength requirements of sacrificial concrete. The polypropylene fibers in the erosion-resistant sacrificial concrete prepared by this invention melt under high-temperature conditions, forming pores and channels, releasing high-temperature steam, which meets the anti-burst performance requirements of sacrificial concrete. The erosion-resistant sacrificial concrete prepared by this invention contains a high content of SiO2 and Fe2O3, which react with the active reducing agents Zr and U in the core melt, thereby reducing hydrogen production and meeting the sacrificial performance requirements. The aluminoferrite cement used in this invention, due to the low alkali characteristics and dense microstructure of its hydrated mineral phases, endows the sacrificial concrete with extraordinary erosion resistance. The steel shot used, through the endothermic solid-liquid phase transformation of high-purity Fe and high-temperature alloying reaction, further enhances the erosion resistance of the sacrificial concrete. The erosion-resistant sacrificial concrete prepared by this invention can not only be used in the core traps of current third-generation nuclear power plants, but also holds promise for use in the core traps of future fourth-generation nuclear power plants, demonstrating significant engineering application value.

[0057] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A sacrificial concrete resistant to erosion, characterized in that: It includes the following components by weight: 300-400 parts of aluminoferrite cement, 30-50 parts of barium ferrite, 100-150 parts of fly ash, 10-50 parts of silica fume, 350-900 parts of quartz sand, 700-900 parts of hematite, 300-1300 parts of steel grit, 3-8 parts of polypropylene fiber, 210-230 parts of water, and 3-9 parts of water-reducing agent.

2. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The steel shot is continuously graded, with a particle size of 0-4 mm and a density of 6000-8000 kg / m³. 3 The steel shot contains not less than 90% Fe, not more than 0.05% S, and not more than 0.05% P.

3. The anti-erosion sacrificial concrete according to claim 2, characterized in that: In the steel shot, the mass ratio of particles with a diameter of 1-2 mm is not less than 40%; the steel shot is in the form of spherical particles, with a hardness of 30-60 HRC and a surface roughness Rz=10-150 μm.

4. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The cement is 42.5 aluminoferrite cement with a particle size range of 0-100μm, an initial setting time of not less than 30min, and a specific surface area greater than 370m². 2 / kg, bulk density is 1300-1600kg / m³ 3 The Fe2O3 content is greater than 6%; the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent.

5. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The fly ash is Class I fly ash, with a particle size range of 0-100 μm and a specific surface area greater than 400 m². 2 / kg, bulk density is 900-1300kg / m³ 3 ; The specific surface area of ​​the silica fume is greater than 15000 m². 2 / kg, with an average particle size of 0.1-0.3μm, of which more than 80% are smaller than 0.1μm.

6. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The quartz sand contains more than 99% SiO2; the mass fraction of quartz sand with a particle size of 0mm-4mm is 56%, and the mass fraction of quartz sand with a particle size of 4mm-8mm is 44%.

7. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The hematite contains 90% or more Fe2O3; the mass fraction of hematite with a particle size of 0mm-4mm is 56%, and the mass fraction of hematite with a particle size of 4mm-8mm is 44%.

8. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The barium ferrite contains more than 12 wt% BaO and more than 83 wt% Fe2O3, and the particle size range of the barium ferrite is 1-100 μm, wherein the proportion of particles with a particle size of less than 50 μm is greater than 80%.

9. The anti-erosion sacrificial concrete according to claim 1, characterized in that: The polypropylene fibers have a length of 10-15 mm, a diameter of 20-50 μm, and a density of not less than 910 kg / m³. 3 The elastic modulus is not less than 3500MPa, and the elongation at break is 15%-30%.

10. A method for preparing erosion-resistant sacrificial concrete as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Mix aluminoferrite cement, fly ash, silica fume, and barium ferrite in a container at a speed of 40-50 rpm for 15-20 minutes to obtain mixture M1; Step 2: Add quartz sand, hematite, and steel shot to the above mixture M1, and stir at a speed of 40-50 rpm for 15-20 minutes to obtain mixture M2; Step 3: Mix a portion of water with the water-reducing agent and add it to the above mixture M2. Stir at 40-50 rpm for 15-20 minutes to obtain mixture M3. Step 4: After rinsing each container with the remaining water, add it to the above mixture M3 and stir at a speed of 40-50 rpm for 8-15 minutes to obtain mixture M4; Step 5: Add polypropylene fibers to the above mixture M4 and continue stirring at a speed of 40-50 rpm for 8-15 minutes to obtain erosion-resistant sacrificial concrete; then mold and cure the erosion-resistant sacrificial concrete.

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