Method for efficiently constructing hydrated calcium silicate nano-scale model with defective silicate chain based on C language

Abstract

The invention relates to a method for efficiently constructing a calcium silicate hydrate nano model with a defective silicate chain based on a C language, and belongs to the technical field of molecular simulation. The method comprises the following steps: deleting all water molecules and hydrogen atoms in a # imgabs0 # tobermorite model, and carrying out orthogonalization and cell expansion to generate an initial model; randomly deleting a silicon dioxide group in the initial model by utilizing an executable file written by a C language, and simulating the defect of a silicate chain in a hydrated calcium silicate structure; randomly deleting part of free oxygen atoms in the model; performing energy minimization on interlayer calcium atoms; immobilization of atoms is cancelled, and Monte Carlo water absorption simulation is carried out; and full relaxation is realized under an isothermal and isobaric ensemble. According to the method, the calcium silicate hydrate model with defects can be efficiently constructed according to the calcium-silicon ratio and nuclear magnetic resonance data measured through the test, the problem that the efficiency of manually removing groups in the process of establishing the calcium silicate hydrate model is low is solved, and the accuracy and operation convenience of model construction are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of molecular simulation technology, and specifically to a method for efficiently constructing a nanoscale model of hydrated calcium silicate with defective silicate chains based on the C language. Background Technology

[0002] Calcium silicate hydrate (CSH) is a crucial component of cementitious materials, and its structure and properties directly influence the material's strength, durability, and other performance characteristics. CSH has a complex structure, exists in various morphologies, and its composition and structure are affected by numerous factors. Clearly, a deep understanding of calcium silicate hydrate at the nanoscale is a fundamental stepping stone for improving the performance of silicate cements and developing novel cement-based materials, and it remains a key scientific challenge in this field.

[0003] Molecular simulation is an effective theoretical method that can reveal the behavior of carbon-silica structures (CSHs) at the atomic scale and provide information about their structure and properties. However, traditional CSH modeling methods often overlook the defects in CSHs, leading to deviations between the models and the real structures. To overcome this limitation, researchers have recently begun to combine experimental data with molecular simulation techniques, using experimental data to guide the construction of nanoscale CSH models to improve model accuracy.

[0004] With the development of neutron scattering technology, our understanding of the structure of CSH has deepened. Neutron scattering measurements show that the calcium-to-silicon ratio (Ca / Si) of CSH ranges from 0.7 to 2.3, and its density is around 2.6 g / cm³. 3 These data provide us with macroscopic information about the structure of CSH. Meanwhile, nuclear magnetic resonance (NMR) technology also provides important information for revealing the microscopic structure of CSH. NMR studies show that the distribution ratio of silicon-oxygen tetrahedra in CSH is approximately: Q0≈10%, Q1≈67%, and Q2≈23%. Here, Q0, Q1, and Q2 represent the proportions of a single silicon-oxygen tetrahedron, a chain-terminal tetrahedron, and a chain-middle tetrahedron, respectively.

[0005] In current research, researchers primarily use manual deletion. Tobermorite ( The silicon dioxide (SiO2) groups in tobermorite satisfy the calcium-silicon ratio provided by neutron scattering data and the Q measured by NMR technology. n The value of n is 0, 1, or 2. This method cannot guarantee randomness, leading to biased results and low efficiency. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a method for efficiently constructing a nanoscale model of hydrated calcium silicate chains with defects using the C programming language. This invention utilizes the C programming language to randomly delete SiO2 groups from the crystallographic information file (cif file) of tobermorite, solving the problem of low SiO2 group deletion rates when manually removing them. Furthermore, this invention can generate arbitrary calcium-to-silicon ratios and satisfy Q based on experimental data. n Distributed random deletion model.

[0007] This invention is achieved through the following technical solution:

[0008] based on First, remove the hydrogen from the water molecules and hydroxyl groups in the tobermorite CIF (Crystallographic Information File) model.

[0009] Furthermore, regarding the deleted The tobermorite was orthogonalized, then expanded, and stored as a test.cif file;

[0010] Furthermore, the executable file generated in C language is used to randomly delete SiO2 groups from the test.cif file to satisfy the calcium-silicon ratio and Q. n distributed;

[0011] Further force field allocation is performed based on the ClayFF force field;

[0012] To further ensure the system is electrically neutral, some free oxygen atoms are randomly removed based on the system's charge.

[0013] Further energy minimization of interlayer calcium;

[0014] Further, the fixation of atoms was removed, and then a Grand Canonical Monte Carlo (GCMC) water absorption simulation was performed;

[0015] Relaxation under the isothermal-isobaric (NPT) ensemble;

[0016] Advantages and beneficial effects of the present invention:

[0017] This invention uses a C language program to implement the... Random deletion of the tobermorite structure effectively improves the randomness of defects in the CSH model and enhances the reliability of the model.

[0018] This invention uses a C language program to randomly delete... The SiO2 groups in the tobermorite model satisfy the experimentally measured Q. n

[0019] The distribution and calcium-silicon ratio significantly improve computational efficiency, facilitate rapid evaluation of the structural features of the model, provide a reliable structural foundation for the construction of the CSH model, and greatly enhance the efficiency of model construction.

[0020] This invention applies C language programs to Tobermorite's random deletion model is constructed, which can generate arbitrary calcium-silicon ratios and satisfy arbitrary Q. n A nanoscale model of hydrated calcium silicate with distributed defective silicate chains. Attached Figure Description

[0021] Figure 1 A schematic diagram of the process for constructing a model of hydrated calcium silicate with defective silicate chains;

[0022] Figure 2 The user interface for the executable file generated in C language according to this invention;

[0023] Figure 3 For expanded cells tobermorite model α=90.000°, β=90.000°, γ=90.0361°);

[0024] Figure 4 This is a model created by randomly deleting a provided cif file using an executable file generated in C.

[0025] Figure 5 This is the model after minimizing the energy of interlayer calcium;

[0026] Figure 6 The model after GCMC water absorption simulation;

[0027] Figure 7 To ensure sufficient relaxation of the model under the NPT ensemble; Detailed Implementation

[0028] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Step 1: Preparation. Place the executable file Random deletion.exe and the initial model file test.cif in the same folder;

[0030] Step 2: Launch the program. Double-click the Random deletion.exe file to run the program;

[0031] Step 3: Enter a filename. The program prompts you to enter a filename. Enter the filename (.cif) and press Enter.

[0032] Step 4: Select model building options. The program displays two options: Option 1: Generate multiple models with the same calcium-silicon ratio and Q. n Random deletion of the range. Option 2: Generate multiple structures with different calcium-silicon ratios and Q. n To randomly delete a structure within a range, select the option and press Enter.

[0033] Step 5: Enter the number of structures to be generated, which represents the total number of structures to be randomly deleted. Press Enter.

[0034] Step 6: Set the maximum number of attempts. The program prompts you to set the maximum number of attempts. Enter a large positive integer to prevent the loop from running out of time, and press Enter.

[0035] Step 7: Set Q n Threshold range. The program will prompt you to enter the threshold ranges for Q0, Q1, and Q2 in sequence. Press Enter to confirm.

[0036] Step 8: Enter the target calcium-silicon ratio. The program prompts you to enter the calcium-silicon ratio of the target structure; press Enter to confirm.

[0037] Step 9: Input target Q n Percentage values. The program will prompt you to enter the percentage values ​​for Q0, Q1, and Q2 of the target structure in sequence. Press Enter to confirm.

[0038] Step 10: Output Results. The program will output the calcium-silicon ratio and Q of the initial structure. n The values, and the calcium-silicon ratio and Q of the CSH model generated after randomly deleting SiO2. n The program will generate a CSH model file named "CS-H_Ca / Si_Q0_Q1_Q2.cif";

[0039] Step 11: Apply the ClayFF force field to the randomly deleted model generated in Step 10. To ensure the system's electrical neutrality, randomly delete some free oxygen atoms based on the system's charge. Minimize the energy of interlayer calcium atoms. Remove atom fixation and perform GCMC water absorption simulation. Perform relaxation under the NPT ensemble.

[0040] Example

[0041] like Figure 1 As shown, a method for efficiently constructing a nanoscale model of hydrated calcium silicate with defective silicate chains using C language is presented. Using test.cif as the initial model, this method is employed to construct the hydrated calcium silicate model. Finally, the correctness of the model is determined through mechanical property simulation. The specific steps include:

[0042] Step 1: Preparation. Place the executable file Random deletion.exe and the test.cif file in the same folder. The test.cif model is as follows: Figure 2 As shown;

[0043] Step 2: Launch the program. Double-click the Random deletion.exe file to run the program;

[0044] Step 3: Type test.cif and press Enter.

[0045] Step 4: Enter option "1" and press Enter;

[0046] Step 5: The program prompts you to enter the number of structures to be generated. Enter "1" to generate one randomly deleted structure, and press Enter.

[0047] Step 6: Enter the maximum number of attempts, "1000". If the target structure is not found after 1000 attempts, a corresponding prompt will be displayed. Press Enter.

[0048] Step 7: The program prompts you to enter the threshold ranges for Q0, Q1, and Q2 in sequence. Enter "5" to indicate that Q0 is within the range of 10.0±5%, Q1 is within the range of 67.0±5%, and Q2 is within the range of 23.0±5%. Press Enter to confirm.

[0049] Step 8: The program prompts you to enter the calcium-silicon ratio of the target structure. Enter "1.70". Press Enter to confirm.

[0050] Step 9: The program prompts you to enter the percentage values ​​of Q0, Q1 and Q2 of the target structure in sequence. Enter "10", "67" and "23" respectively, which means that Q0 accounts for 10%, Q1 accounts for 67% and Q2 accounts for 23%. Press Enter to confirm.

[0051] Step 10: The program will output the calcium-silicon ratio and Q of the initial structure. n The values, and the calcium-silicon ratio and Q of the CSH model generated after randomly deleting SiO2. n The program generated a CSH model file named "CS-H_1.69_12.94%_68.24%_18.82%.cif", as shown below. Figure 3 As shown;

[0052] Step 11: Apply the ClayFF force field to the randomly deleted model generated in Step 10. To ensure the system's electrical neutrality, randomly delete some free oxygen atoms based on the system's charge, such as... Figure 4 As shown. Energy minimization is performed on the interlayer calcium atoms, such as... Figure 5 As shown. The atom fixation is removed, and a GCMC water absorption simulation is performed, as follows. Figure 6 As shown. Relaxation is performed under the NPT ensemble, as follows. Figure 7 As shown, the final molecular formula of the model is (CaO). 1.69 (SiO2)·(H2O) 1.69 .

[0053] Step 12: The mechanical properties of the constructed calcium silicate hydrate model were simulated using the constant strain method. The simulation results are shown in Table 1.

[0054] Table 1 Simulation results of mechanical properties of hydrated calcium silicate

[0055]

[0056] The simulation results show that the mechanical performance parameters of the CSH model are consistent with the simulation results in relevant literature, indicating that the method has high reliability.

[0057] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for efficiently constructing a nanoscopic model of calcium silicate hydrate with defective silicate chains based on C language, characterized in that: The steps include: Step 1. Basic model construction. Delete Tobermorite tobermorite) and perform orthogonalization and cell expansion, and then generate a cif (Crystallographic Information File) file for testing. The test file name is test.cif; Step 2. Random deletion model construction. Place the executable file Random deletion.exe and the test.cif file generated by C language in the same folder. Run the executable file, enter the relevant parameters according to the prompt information of the executable file, and generate the nanoscopic model of calcium silicate hydrate without water absorption after random deletion; Step 3. Energy minimization. Based on the ClayFF force field, force field distribution is performed on the model after random deletion. To ensure that the system is electrically neutral, some free oxygen atoms are randomly deleted according to the charge of the system, and then the energy of the interlayer calcium is minimized; Step 4. GCMC (Grand Canonical Monte Carlo) water absorption simulation. Unfix the atoms and then perform GCMC water absorption simulation to simulate the water absorption process of hydrated calcium silicate; Step 5. Relaxation in an isothermal and isobaric ensemble (NPT) Relaxation for 2000 ps in the NPT ensemble allows the model to reach thermodynamic equilibrium.

2. The method for efficiently constructing a nanoscopic model of calcium silicate hydrate with defective silicate chains based on C language according to claim 1, characterized in that: In step 2 of the present invention, different calcium-silicon ratios and different Q n (n is 0, 1, 2) distribution model (where Q0, Q1, and Q2 represent the proportions of single silicon-oxygen tetrahedrons, chain-end tetrahedrons, and chain-mid tetrahedrons, respectively).

3. The method for efficiently constructing a nanoscopic model of calcium silicate hydrate with defective silicate chains based on C language according to claim 1, characterized in that: The executable file Random deletion.exe in step 2 of the present invention can output the calcium-silicon ratio and Q of the initial structure. n The output is the calcium-silicon ratio and Q of the calcium silicate hydrate (CSH) model generated by randomly deleting the silicon dioxide (SiO2) group. n value.

4. The method for efficiently constructing a nanoscopic model of calcium silicate hydrate with defective silicate chains based on C language according to claim 1, characterized in that: The executable file in step 2 of the present invention will generate a CSH model file named "CS-H_Ca / Si_Q0_Q1_Q2.cif".

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