Simulation method for preparing new concrete from muck based on Materials Studio

Abstract

The invention discloses a simulation method for preparing new concrete from muck based on Materials Studio, which comprises the following steps: obtaining the new concrete of muck at the age of 28 days, and carrying out molecular test and microscopic test to obtain the components, proportion and average pore size of the new concrete of muck; setting initial density, calling molecular models corresponding to the components according to the initial density and the molecular types and proportions of the concrete, setting the number of the molecular models according to the proportions corresponding to the molecular types, and setting aperiodic boundary conditions to obtain a concrete model; selecting a force field model to obtain a muck new concrete molecular dynamics model; molecular dynamics calculation is carried out on the muck new concrete molecular dynamics model to simulate mechanical properties of muck new concrete, and researchers are helped to verify whether the improved muck new concrete has considerable mechanical properties or not after improving muck new concrete materials, so that the analysis efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of computer simulation, and in particular to a simulation method, system and medium for preparing new-quality concrete from slag based on Materials Studio. Background Art

[0002] Excavated soil is a common solid waste material. For example, large quantities of excavated soil are discharged annually during tunnel and underground engineering construction. The rational utilization of excavated soil is a crucial issue for economic efficiency and raw material conservation. Concrete typically contains large amounts of sand and gravel. In recent years, the extraction of these materials has been restricted, and the supply of high-quality sand and gravel along construction routes has been challenging. Excavated soil, especially weak excavated soil with low compressive strength and high weathering, cannot be converted into sand and gravel and is mostly discarded for landfill. Currently, construction in complex mountainous areas and urban areas is increasingly facing practical challenges such as "nothing to discard, difficulty transporting, and long transportation distances." The construction and operation of waste dumps also face significant pressures, including the occupation of arable land, safety, ecological issues, and environmental and water conservation. Therefore, the comprehensive replacement of excavated soil with sand and gravel to produce new-quality concrete is of great significance for promoting new-quality productivity and low-carbon environmental protection in the civil engineering field. Replacing sand and gravel in concrete with slag soil creates a new concrete mix with a completely new mix ratio. Verifying the mechanical properties of this new concrete is typically done through experimental and theoretical analysis. However, experimental analysis is cumbersome, inefficient, and dominated by macroscopic observations, making it difficult to explain the inherent mechanical mechanisms of the new concrete. Therefore, optimal molecular-level simulation analysis of slag soil-based new concrete is a key challenge. Summary of the Invention

[0003] The purpose of the present invention is to provide a simulation method for preparing new concrete from slag soil based on Materials Studio. By using Material Studio software, the mechanical properties of new concrete from slag soil are simulated and analyzed to observe whether the new concrete from slag soil has equivalent mechanical properties at the molecular level.

[0004] To achieve the above object, the present invention adopts the following scheme: This application provides a simulation method for preparing new quality concrete from slag based on Materials Studio, which specifically includes the following steps: S1. Obtain 28-day-old fresh soil concrete for molecular testing and microscopic testing to determine the composition, proportion, and average pore size of the fresh soil concrete; S2. In Material Studio, set the initial density. Based on the initial density and the molecular types and proportions of the new muck concrete, call the molecular models corresponding to each component. Set the number of molecular models based on the proportions of each molecular type, and set non-periodic boundary conditions to obtain the new muck concrete model. S3. In Material Studio software, select the force field model for the new slag soil concrete model to obtain the new slag soil concrete molecular dynamics model; S4. In Material Studio software, molecular dynamics calculations are performed on the molecular dynamics model of new slag soil concrete to simulate the mechanical properties of the new slag soil concrete.

[0005] In some specific implementation schemes, the components of the new concrete made of slag soil include aluminum oxide. When calling the molecular model corresponding to aluminum oxide in step S2, it is necessary to first construct the aluminum oxide molecular model in the Material Studio software and pre-store it in the crystal library.

[0006] In some specific embodiments, the specific process of constructing the aluminum oxide molecular model includes: Calling a preset number of aluminum atoms and oxygen atoms, and arranging the preset number of aluminum atoms and oxygen atoms into a molecular structure of aluminum oxide; According to the Lang's Handbook of Chemistry, the distance and foot between aluminum atoms and oxygen atoms were queried, and ionic bonds were set to connect each atom to obtain the aluminum oxide helical structure. The aluminum oxide structure was then adjusted through the energy minimization step provided by the Material Studio software to obtain the aluminum oxide molecular model.

[0007] In some specific embodiments, the force field model selected in step S3 is the Compass force field.

[0008] In some specific embodiments, the molecular dynamics calculation method in step S4 includes: Using the Forcite module, a 50,000-step run was set up, and a 250-ps dynamics simulation was performed in the NPT ensemble at an ambient temperature of 298.15 K and an atmospheric pressure of 0.0001 GPa. This was followed by a 250-ps simulation in the NVT ensemble at constant temperature and volume, with a time step of 1 fs. Set the necessary conditions: set the decay constant of the Berendsen barostat pressure to 0.1 ps and the decay constant of the Nose thermostat temperature to 0.01 Q; The electrostatic term is calculated using the Ewald summation method, and the van der Waals term is calculated using the average pore size of the new concrete with soil slag. The interaction between the electrostatic and van der Waals terms is calculated using the Ewald summation method at a repulsion cutoff distance of 12.5. Choose an appropriate optimization algorithm.

[0009] In some specific implementation schemes, when selecting a force field model for the concrete model in step S3, the van der Waals term is set to be proportional to the square of the average pore width of the new slag concrete.

[0010] In some embodiments, the optimization algorithms include Newton-Raphson, conjugate gradient, and steepest descent methods.

[0011] In some specific embodiments, the initial density in step S2 is set to 2.1 g / cm 3 .

[0012] The present invention has the beneficial effects: The present invention uses molecular dynamics simulation method to simulate the relevant mechanical properties of new slag concrete, which can help researchers verify whether the improved new slag concrete has equivalent mechanical properties after the improved slag concrete material, thereby improving analysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A flow chart of a simulation method for preparing new concrete from slag based on Materials Studio provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the aluminum oxide molecular model constructed according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0015] Unless otherwise specifically stated, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0016] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0017] Additionally, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness. Those skilled in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0018] Technologies, methods and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods and equipment should be considered part of the authorization specification.

[0019] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0020] Example 1 like Figure 1 As shown, this embodiment provides a simulation method for preparing new quality concrete from slag based on Materials Studio, which specifically includes the following steps: S1. Obtain 28-day-old fresh soil concrete for molecular testing and microscopic testing to determine the composition, proportion, and average pore size of the fresh soil concrete; S2. In Material Studio, set the initial density to 2.1g / cm 3 According to the initial density and the molecular types and proportions of the new slag soil concrete, the molecular models corresponding to each component are called, and the number of molecular models is set according to the proportions of each molecular type, and the non-periodic boundary conditions are set to obtain the new slag soil concrete model; The components of the new concrete made from slag soil include aluminum oxide. When calling the molecular model corresponding to aluminum oxide in step S2, it is necessary to first construct the aluminum oxide molecular model in the Material Studio software and pre-store it in the crystal library.

[0021] Specifically, the specific process of constructing the aluminum oxide molecular model includes: Calling a preset number of aluminum atoms and oxygen atoms, and arranging the preset number of aluminum atoms and oxygen atoms into a molecular structure of aluminum oxide; According to the Lang's Handbook of Chemistry, the distance and foot between aluminum atoms and oxygen atoms were queried, and ionic bonds were set to connect each atom to obtain the aluminum oxide helical structure. The aluminum oxide structure was then adjusted through the energy minimization step provided by the Material Studio software to obtain the aluminum oxide molecular model.

[0022] S3. In Material Studio software, select the force field model for the new slag soil concrete model to obtain the new slag soil concrete molecular dynamics model; Specifically, the force field model is the Compass force field, and considering that new slag concrete already contains aluminum oxide, when slag is used to replace sand and gravel, the obtained new slag concrete will also add additional aluminum oxide elements. Since aluminum oxide is an amphoteric oxide, it is extremely easy to undergo redox reactions under acidic or alkaline conditions. Therefore, it is necessary to increase the short-range force between particles when setting the force field. The specific setting method is to add the total energy calculation formula under the Compass force field that comes with the system. Under the selected Compass force field model, the van der Waals term is set to be proportional to the square of the average pore width of the new slag concrete.

[0023] S4. In Material Studio software, molecular dynamics calculations are performed on the molecular dynamics model of new slag soil concrete to simulate the mechanical properties of the new slag soil concrete.

[0024] The molecular dynamics calculation method in step S4 includes: Using the Forcite module, a 50,000-step run was set up, and a 250-ps dynamics simulation was performed in the NPT ensemble at an ambient temperature of 298.15 K and an atmospheric pressure of 0.0001 GPa. This was followed by a 250-ps simulation in the NVT ensemble at constant temperature and volume, with a time step of 1 fs. Set the necessary conditions: set the decay constant of the Berendsen barostat pressure to 0.1 ps and the decay constant of the Nose thermostat temperature to 0.01 Q; The electrostatic term is calculated using the Ewald summation method, and the van der Waals term is calculated using the average pore size of the new concrete with soil slag. The interaction between the electrostatic and van der Waals terms is calculated using the Ewald summation method at a repulsion cutoff distance of 12.5. Select an appropriate optimization algorithm, including Newton-Raphson, conjugate gradient, and steepest descent methods.

[0025] With the above method for simulating the mechanical properties of new slag soil concrete, the above method can be used to simulate different new slag soil concretes. For example, the above method can be used to verify that the mechanical properties of ordinary concrete containing sand and gravel are equivalent to those of new slag soil concrete in which sand and gravel are replaced by slag soil. The method includes the following steps: 1. Prepare concrete specimens for simulation Ordinary concrete was prepared according to standard methods. To prepare the new slag-soil concrete, slag-soil was used to replace the sand and gravel in ordinary concrete. The weighed slag-soil and cement (using PO42.5 grade ordinary Portland cement) were placed in a mixer and stirred for 30 seconds. Water was then added to the mixer several times. The mixture was then stirred for 3 minutes until a homogeneous mixture was formed. The mixed concrete was poured into a mold (100 mm × 100 mm × 100 mm) and placed on a vibrating table for 1 minute. It was then covered with plastic wrap and allowed to rest for 18 hours. Finally, the concrete was demolded under standard curing conditions and grouped for curing for 1, 3, 7, and 28 days.

[0026] During concrete preparation, it's also important to consider that when constructing models for ordinary concrete, in order to ensure that the components are in the correct proportions and that the proportions are more accurate, it's necessary to increase the weight concentration of the cement component, which results in an expansion of the overall size of the composite cement unit. This is because some components in the model are present in smaller quantities, requiring more cement to reach 100%. However, in new slag concrete, the density of the slag itself can be relatively low, making it highly compressible during construction. When the slag replaces some of the sand and gravel, the density changes. To achieve the same density as ordinary concrete, the slag's greater deformation properties can be exploited by changing the density of the slag itself. For example, by using appropriate compression or water expansion as in actual construction, the overall volume can be maintained constant after replacing the sand. Specifically, to ensure that ordinary concrete and new slag concrete meet the same conditions during molecular dynamics simulations, the density of the new slag concrete with different replacement ratios must be adaptively adjusted so that the density of both ordinary concrete and new slag concrete remains consistent during simulations, at 2.1 g / cm. 3 .

[0027] The process of adaptive adjustment of density of new soil concrete is as follows: Assume that the density of concrete with mass 1 is set to a , if we decide to remove the mass m of sand and gravel (sand and gravel), and assuming that the volume of this part of sand and gravel is v , the quality needs to be m To ensure that the volume remains constant, the volume of sand and gravel removed and the volume of added slag must remain constant, that is, the volume is v .

[0028] Then assume that the existing muck mass is m 0, volume is v 0, because the slag has a strong ability to absorb and repel water. It can be removed by adding water (the density of water is 1, i.e. m 水 = v 水 )ensure; ( m 0+ m 水 ) / ( v 0+ v 水 ) = m / v (1), m 水 = v 水 (2), combined with formula (1) and (2), it can be calculated m 水 、 v 水 After adding or reducing water, stir the soil evenly and then take m Come out and meet the requirements.

[0029] 2. Use Material Studio software for simulation calculations. Using statistical mechanics and thermodynamics principles to calculate macroscopic physical properties based on motion trajectories, the mechanical properties of ordinary concrete and new slag concrete were evaluated. This helped researchers verify whether the mechanical properties of new slag concrete and ordinary concrete were equivalent, thereby identifying the new slag concrete with the optimal replacement rate. The specific process is as follows: 2.1 Establishment of concrete model The concrete model was established based on 28-day-old concrete. At this time, it can be considered that the cement in the concrete has been completely hydrated, and the model was built according to the various proportions of the concrete.

[0030] Based on an existing crystal database and analysis of SEM, EDS, and XRD data, Material Studio software was used for simulation calculations. Statistical mechanics and thermodynamics were used to calculate macroscopic physical properties based on the motion trajectory. A molecular dynamics model was constructed using the main components of cement and its additives, limestone powder and silica fume. Using fresh concrete made from slag as an example, some of its components are shown in Table 1: Table 1 Composition and proportion of new concrete made from slag soil Before performing molecular dynamics simulation on the concrete model, considering that in most concrete models, there is no aluminum oxide molecular model in the crystal library, it is necessary to first establish an aluminum oxide molecular model and store it in the crystal library. When this model is established, the aluminum oxide molecular model used is as follows: Figure 2 As shown, this form is used mainly because the environment in which concrete is located is relatively complex and it is extremely prone to acidic and alkaline redox reactions. Therefore, the spiral structure of aluminum oxide is easy to connect with external molecules.

[0031] After obtaining the crystal library containing the aluminum oxide molecular model, the concrete building process for ordinary concrete and new slag concrete is similar, with different parameter settings. The specific process of model building is as follows: 1. Obtain 28-day-old concrete for molecular testing to obtain component analysis results. Based on the component analysis results, the AC module (Amorphous Cell) of the amorphous cell was used to build the concrete model. The molecular models of each component were called from the crystal library. All input cells used aperiodic boundary conditions to build the concrete model. This process used the amorphous cell module, taking into account the initial density and the percentage of loaded molecules. The initial density input value was 2.1g / cm 3 .

[0032] 2. Select the force field model and choose compass force field; 2.2 Molecular dynamics simulation Here, the simulation conditions for ordinary concrete and new slag concrete are basically the same. The difference is that the addition of slag will add more alumina to the new slag concrete. Since it is an amphoteric oxide, it is extremely easy to undergo redox reactions under acidic or alkaline conditions. Therefore, for the new slag concrete, compared with ordinary concrete, when setting the force field, it is necessary to increase the short-range force between particles to simulate the real situation. The specific setting method is to increase the weight coefficient of the van der Waals term in the total energy calculation formula under the Compass force field. Compared with the weight coefficient of the van der Waals term of ordinary concrete, it generally needs to be increased by more than 10%.

[0033] Specifically, the van der Waals term of fresh concrete with slag soil can be determined experimentally. Specimens of 28-day-old fresh concrete with slag soil are subjected to microscopic testing, such as thermogravimetric analysis and CT scanning. The average pore size of the specimens can be measured. Once the average pore size is determined, the weighting coefficient of the van der Waals term can be determined, as the van der Waals term is proportional to the square of the pore width.

[0034] In order to further verify the correctness of the new concrete made from slag soil, the RDF curve can also be used to compare the elastic modulus and FFV of the new concrete made from slag soil and ordinary concrete to indicate the effectiveness of the new concrete made from slag soil. Taking the elastic modulus as an example, this indicator can be used to show the applicability of the new concrete made from slag soil: In order to quantitatively analyze the mechanical properties of the established model, the shear modulus ( G ), Young's modulus ( E ), bulk modulus ( K ) and Poisson's ratio ( v) and other indicators. In order to verify the model, the elastic modulus was calculated, and the elastic stiffness coefficient was initially calculated by the constant strain method.

[0035] The elastic flexibility matrix components are given by ( ) is derived from the inverse functions of the elastic stiffness matrix components. In this matrix, the subscripts (R) and (V) denote Reuss and Voigt, respectively. The true values ​​of a material's bulk and shear moduli lie between the estimates obtained from Reuss and Voigt. Therefore, the average of the Reuss and Voigt values ​​(the Voigt-Reuss-Hill (VRH) average) is expressed as: K VRH and G VRH There are two averaging methods for the calculation of Poisson's ratio and Young's modulus, as shown in the equations: According to the actual situation of the model, the Mechanicalproperties function in the Forcite module of Material Studio software was used to calculate the established model, and the elastic stiffness matrix and elastic flexibility matrix were obtained. Based on these two matrices and the calculation formula mentioned above, the elastic modulus of the model was established.

[0036] The elastic modulus quantifies the mechanical properties of the model. For different replacement ratios of slag for sand and gravel, the elastic modulus is correlated with the macroscopic mechanical properties. The model can derive trends in the elastic modulus at the atomic level, showing a regular pattern of change with varying replacement ratios. Because compressive strength and elastic modulus are strongly correlated, empirical formulas are often used to predict the elastic modulus from compressive strength data. However, this relationship depends on specimen shape and size, as well as other uncontrollable parameters. Generally speaking, the elastic modulus decreases with decreasing compressive strength, regardless of other parameters. In this study, studying compressive strength and elastic modulus together is ineffective because compressive strength is obtained from macroscopic experiments, while elastic modulus is calculated at the atomic level. However, comparing their trends is an effective approach. Comparing the compressive strength histogram with the elastic modulus histogram reveals similar trends: the elastic modulus increases with increasing slag content, and there is a positive correlation between the two. This demonstrates that the established model can estimate the mechanical properties of cement composites at the atomic level. In other words, the elastic modulus calculated by the present invention is within a reasonable range. The model of the present invention can provide additional information on the modulus, such as Poisson's ratio, bulk modulus, shear modulus, and Young's modulus.

[0037] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Based on the technical essence of the present invention and within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement of the above embodiment shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A simulation method for preparing new quality concrete from slag based on Materials Studio, characterized in that: The specific steps include: S1. Obtain 28-day-old fresh soil concrete for molecular testing and microscopic testing to determine the composition, proportion, and average pore size of the fresh soil concrete; S2. In Material Studio, set the initial density. Based on the initial density and the molecular types and proportions of the new muck concrete, call the molecular models corresponding to each component. Set the number of molecular models based on the proportions of each molecular type, and set non-periodic boundary conditions to obtain the new muck concrete model. S3. In Material Studio software, select the force field model for the new slag soil concrete model to obtain the new slag soil concrete molecular dynamics model; S4. In Material Studio software, molecular dynamics calculations are performed on the molecular dynamics model of new slag concrete to obtain the mechanical properties of the new slag concrete.

2. The simulation method for preparing new quality concrete from slag based on Materials Studio according to claim 1, characterized in that: The components of the new concrete made from slag soil include aluminum oxide. When calling the molecular model corresponding to aluminum oxide in step S2, it is necessary to first construct the aluminum oxide molecular model in the Material Studio software and pre-store it in the crystal library.

3. The simulation method for preparing new quality concrete from slag based on Materials Studio according to claim 2, characterized in that: The specific process of constructing the aluminum oxide molecular model includes: Calling a preset number of aluminum atoms and oxygen atoms, and arranging the preset number of aluminum atoms and oxygen atoms into a molecular structure of aluminum oxide; According to the Lang's Handbook of Chemistry, the distance and foot between aluminum atoms and oxygen atoms were queried, and ionic bonds were set to connect each atom to obtain the aluminum oxide helical structure. The aluminum oxide structure was then adjusted through the energy minimization step provided by the Material Studio software to obtain the aluminum oxide molecular model.

4. The simulation method for preparing new quality concrete from slag based on Materials Studio according to claim 1, characterized in that: The force field model selected in step S3 is the Compass force field.

5. The simulation method for preparing new quality concrete from slag based on Materials Studio according to claim 1, characterized in that: The molecular dynamics calculation method in step S4 includes: Using the Forcite module, a 50,000-step run was set up, and a 250-ps dynamics simulation was performed in the NPT ensemble at an ambient temperature of 298.15 K and an atmospheric pressure of 0.0001 GPa. This was followed by a 250-ps simulation in the NVT ensemble at constant temperature and volume, with a time step of 1 fs. Set the necessary conditions: set the decay constant of the Berendsen barostat pressure to 0.1 ps and the decay constant of the Nose thermostat temperature to 0.01 Q; The electrostatic term was calculated using the Ewald summation method, the van der Waals term was calculated using the average pore size of the concrete, and the interaction between the electrostatic and van der Waals terms was calculated using the Ewald summation at a repulsion cutoff distance of 12.5; Choose an appropriate optimization algorithm.

6. The simulation method for preparing new quality concrete from slag based on Materials Studio according to claim 5, characterized in that: When selecting a force field model for the new muck concrete model in step S3, the van der Waals term is set to be proportional to the square of the average pore width of the new muck concrete.

7. The simulation method for preparing new concrete from slag based on Materials Studio according to claim 5, characterized in that: Optimization algorithms include Newton-Raphson, conjugate gradient, and steepest descent methods.

8. The simulation method for preparing new concrete from slag based on Materials Studio according to claim 1, characterized in that: In step S2, the initial density is set to 2.1 g / cm 3 .

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