Steel slag-rubber asphalt bonding interface evaluation method
Through molecular dynamics simulation technology, the interface molecular model of steel slag-rubber asphalt was constructed and destroyed, which solved the problem of low accuracy and inability to clarify the type of damage in the existing technology, achieved high-precision interface evaluation and type identification of damage, and promoted the comprehensive utilization and design optimization of materials.
Patent Information
- Application Number
- CN202411773695.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-03-25
AI Technical Summary
When evaluating the damage state of the steel slag-rubber asphalt bonding interface, the prior art is not very accurate, and the type of damage of the interface cannot be identified, which affects the comprehensive utilization of steel slag and rubber asphalt.
Molecular dynamics simulation technology is used to construct a molecular model of the steel slag-rubber asphalt bond interface, apply tensile stress until failure, and obtain molecular dynamics indexes through dynamic calculations, measure the residual thickness of rubber asphalt in the failure model, and determine the type of damage of the interface.
The objectivity of the evaluation of the steel slag-rubber asphalt bond interface is improved, the type of interface failure is clarified, theories guide the design of the mix ratio and the control of the forming environment, and the material design efficiency and functional realization are improved.
Smart Images
Figure CN119688574A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of road paving material performance evaluation, and in particular to a steel slag-rubber asphalt bonding interface evaluation method. Background Art
[0002] Steel slag is the main solid waste of the steel industry, with the characteristics of large output, high stock and difficulty in utilization. At present, using steel slag as aggregate for road paving materials is the mainstream method of steel slag resource utilization. Rubber asphalt is a high-performance road paving material binder made from waste rubber modified asphalt. Using steel slag as aggregate and rubber asphalt as binder to prepare dual solid waste road paving materials can improve the performance of road surface while realizing the resource utilization of bulk solid waste.
[0003] The interface behavior, state and strength between steel slag and rubber asphalt determine the performance and life of dual solid waste road paving materials. Accurate evaluation of the failure state of the steel slag-rubber asphalt interface is conducive to the comprehensive utilization of steel slag and rubber asphalt.
[0004] At present, the evaluation method of the bonding interface of solid waste resource road paving materials still uses the traditional macro tensile test evaluation method. This traditional method is seriously affected by the conditions such as specimen molding and test environment, the test accuracy is not high, and it is impossible to know the damage type of the steel slag-rubber asphalt interface. Summary of the invention
[0005] The purpose of the present invention is to provide a method for evaluating the steel slag-rubber asphalt bonding interface. The method of the present invention can greatly improve the objectivity of the steel slag-rubber asphalt bonding interface evaluation and can clarify the damage type of the steel slag-rubber asphalt interface.
[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:
[0007] The present invention provides a method for evaluating a steel slag-rubber asphalt bonding interface, comprising the following steps:
[0008] respectively constructing an asphalt molecular group model and a rubber representative molecular model, and constructing a rubber asphalt molecular group model according to the asphalt molecular group model and the rubber representative molecular model;
[0009] Constructing a steel slag representative molecular model, and constructing a steel slag-rubber asphalt bonding interface molecular model based on the steel slag representative molecular model and the rubber asphalt molecular group model;
[0010] Applying tensile stress to the steel slag-rubber asphalt bonding interface molecular model in a direction perpendicular to the steel slag-rubber asphalt bonding interface, so that the steel slag-rubber asphalt bonding interface molecular model is destroyed until a stable state is reached, thereby obtaining a destruction model;
[0011] Performing dynamic calculation on the steel slag-rubber asphalt bonding interface molecular model and the destruction model to obtain molecular dynamics indicators of the steel slag-rubber asphalt bonding interface molecular model, wherein the molecular dynamics indicators include interaction energy density, radial distribution function and radial distribution concentration; determining the bonding strength between steel slag and rubber asphalt according to the molecular dynamics indicators;
[0012] Measuring the residual thickness of rubber asphalt on the surface of steel slag in the failure model as the thickness of the steel slag-rubber asphalt adhesion interface, and determining the failure type of the steel slag-rubber asphalt interface according to the thickness of the steel slag-rubber asphalt adhesion interface;
[0013] The steel slag-rubber asphalt bonding interface is evaluated according to the bonding strength between the steel slag and rubber asphalt and the damage type of the steel slag-rubber asphalt interface.
[0014] Preferably, the thickness of the steel slag-rubber asphalt adhesion interface is denoted as H. When H>0, the failure type of the steel slag-rubber asphalt interface is bonding failure; when H=0, the failure type of the steel slag-rubber asphalt interface is adhesion failure.
[0015] Preferably, after the asphalt molecular group model, rubber representative molecular model, rubber asphalt molecular group model, steel slag representative molecular model and steel slag-rubber asphalt bonding interface molecular model are constructed, they are independently optimized, and the optimization process includes sequentially performing geometric optimization, annealing treatment and kinetic optimization.
[0016] Preferably, the geometry optimization includes: using the GeometryOptimization tool of the Forcite module to perform geometry optimization under the COMAPASSII force field until the energy converges and stabilizes;
[0017] The annealing process includes: using the Anneal tool of the Forcite module to perform annealing under the NVE ensemble, and the number of iterations is not less than 100,000 times;
[0018] The kinetic optimization includes: performing kinetic optimization for at least 100 ps at a temperature of 1500 K, and then performing kinetic optimization for at least 200 ps at a temperature of 298 K.
[0019] Preferably, the rubber asphalt molecular group model further includes rationality verification after the optimization process is completed, and the rationality verification includes: deriving the density of the rubber asphalt molecular group model at 25°C to be 1-1.1 g / cm 3 , which is consistent with the density range of rubber asphalt. The rubber asphalt molecular group model is reasonable in representing the properties of rubber asphalt.
[0020] Preferably, the steel slag representative molecular model also includes rationality verification after the optimization process is completed, and the rationality verification includes: using the MechanicalProperties module to calculate the elastic modulus and Poisson's ratio of the steel slag representative molecular model after the optimization process, and the calculated elastic modulus and Poisson's ratio are consistent with the elastic modulus and Poisson's ratio obtained from the steel slag test, and the steel slag representative molecular model has the rationality to represent the properties of steel slag.
[0021] Preferably, the interaction energy density is obtained according to Formula 1 and Formula 2:
[0022] E i =E AB -E A -E B Formula 1;
[0023] E i-ρ =|E i / S| Formula 2;
[0024] Among them, E i is the interaction energy between molecules A and B; E AB is the molecular potential energy of the mixture of molecules A and B; E A is the molecular potential energy of molecule A; E B is the molecular potential energy of molecule B; S is the interface area; E i-ρ is the interaction energy density between molecules A and B.
[0025] Preferably, the radial distribution function is as shown in Formula 3:
[0026]
[0027] Among them, g A-B (r) is the probability of molecule B appearing when the distance from molecule A is r; N A is the number of molecules A; N B is the number of molecules B; r is the distance between molecules A and B; N AB is the number of molecules A and B; V is the spatial volume of the system; I is the Ith molecule, J is the Jth molecule; r Ai is the distance from the first molecule A to the molecule B; r Aj is the distance from the Jth molecule A to molecule B.
[0028] Preferably, the radial distribution concentration is obtained according to Formula 4:
[0029]
[0030] Among them, RC A is the radial distribution concentration; N Ais the number of molecules A; V is the spatial volume of the system; c s is the concentration of the system.
[0031] Preferably, the steel slag-rubber asphalt bonding interface molecular model is replaced by a steel slag-water-rubber asphalt bonding interface molecular model or a steel slag-inorganic salt aqueous solution-rubber asphalt bonding interface molecular model.
[0032] Beneficial effects: The present invention provides a method for evaluating the steel slag-rubber asphalt bonding interface. The present invention realizes the steel slag-rubber asphalt interface evaluation through molecular dynamics simulation technology, which can accurately restore the interface molecular contact relationship of steel slag-rubber asphalt, and greatly improves the objectivity of the evaluation; the present invention uses molecular dynamics simulation technology to measure the rubber asphalt after the steel slag-rubber asphalt is destroyed after load, and obtains the residual rubber asphalt thickness at the molecular scale. On this basis, the type of steel slag-rubber asphalt interface damage can be judged, that is, whether it is adhesion damage or bonding damage. It can theoretically guide the macro conditions such as the mix ratio design of steel slag rubber asphalt mixture and the molding environment control, and can serve as a theoretical basis for the targeted material design of steel slag rubber asphalt mixture, thereby improving the material design efficiency of steel slag rubber asphalt mixture and the realization of functionality. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a schematic diagram of the representative molecular model of steel slag;
[0034] Figure 2 Schematic diagram of the molecular model of the steel slag-rubber asphalt bonding interface;
[0035] Figure 3 Schematic diagram of the changes in the molecular behavior of steel slag-rubber asphalt under tensile stress. DETAILED DESCRIPTION
[0036] The present invention provides a method for evaluating a steel slag-rubber asphalt bonding interface, comprising the following steps:
[0037] respectively constructing an asphalt molecular group model and a rubber representative molecular model, and constructing a rubber asphalt molecular group model according to the asphalt molecular group model and the rubber representative molecular model;
[0038] Constructing a steel slag representative molecular model, and constructing a steel slag-rubber asphalt bonding interface molecular model based on the steel slag representative molecular model and the rubber asphalt molecular group model;
[0039] Applying tensile stress to the steel slag-rubber asphalt bonding interface molecular model in a direction perpendicular to the steel slag-rubber asphalt bonding interface, so that the steel slag-rubber asphalt bonding interface molecular model is destroyed until a stable state is reached, thereby obtaining a destruction model;
[0040] Performing dynamic calculation on the steel slag-rubber asphalt bonding interface molecular model and the destruction model to obtain molecular dynamics indicators of the steel slag-rubber asphalt bonding interface molecular model, wherein the molecular dynamics indicators include interaction energy density, radial distribution function and radial distribution concentration; determining the bonding strength between steel slag and rubber asphalt according to the molecular dynamics indicators;
[0041] Measuring the residual thickness of rubber asphalt on the surface of steel slag in the failure model as the thickness of the steel slag-rubber asphalt adhesion interface, and determining the failure type of the steel slag-rubber asphalt interface according to the thickness of the steel slag-rubber asphalt adhesion interface;
[0042] The steel slag-rubber asphalt bonding interface is evaluated according to the bonding strength between the steel slag and rubber asphalt and the damage type of the steel slag-rubber asphalt interface.
[0043] In view of the defects of the traditional steel slag-rubber asphalt bonding interface evaluation method (such as the macro tensile test evaluation method) such as low precision, long time consumption, high cost, and inability to know the type of steel slag-rubber asphalt interface damage, the present invention provides a steel slag-rubber asphalt bonding interface evaluation method based on molecular dynamics simulation technology, which calculates the steel slag-rubber asphalt bonding interface strength at the molecular scale, and reads the thickness parameters of the steel slag-rubber asphalt interface after damage to clarify the damage type, and realizes the steel slag-rubber asphalt bonding interface evaluation based on the bonding strength of steel slag and rubber asphalt and the damage type of the steel slag-rubber asphalt interface. The method of the present invention is described in detail below.
[0044] The present invention constructs an asphalt molecular group model and a rubber representative molecular model respectively, and constructs a rubber asphalt molecular group model based on the asphalt molecular group model and the rubber representative molecular model. The construction methods of the asphalt molecular group model and the rubber representative molecular model are first described in detail below.
[0045] As an embodiment of the present invention, the method for constructing the asphalt molecular group model may include: using the Amorphous Cell module to combine the molecular models representing the four components of asphaltene, colloid, saturated fraction and aromatic fraction (i.e., the four components of matrix asphalt), and adjusting the proportion of the molecular models of each component according to the proportion of the four components of matrix asphalt to construct the asphalt molecular group model. As an embodiment of the present invention, the proportion of the four components of matrix asphalt can be obtained by the T0618-1993 asphalt chemical component test (four-component method) specified in the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011).
[0046] As an embodiment of the present invention, after the asphalt molecular group model is constructed, it also includes optimization processing, and the optimization processing may include sequentially performing geometry optimization, annealing and dynamic optimization. As an embodiment of the present invention, the geometry optimization specifically includes: using the Geometry Optimization tool of the Forcite module to perform geometry optimization under the COMAPASS II force field until the energy convergence is stable; the annealing process specifically includes: using the Anneal tool of the Forcite module to perform annealing under the NVE ensemble, and the number of iterations is not less than 100,000 times; the dynamic optimization specifically includes: performing dynamic optimization for at least 100ps at a temperature of 1500K, and then performing dynamic optimization for at least 200ps at a temperature of 298K. The present invention can eliminate unreasonable configurations and unreasonable potential energies generated in the process of molecular model construction through optimization processing, which is conducive to improving the rationality and representativeness of the constructed model to ensure the overall accuracy of the simulation calculation.
[0047] As an embodiment of the present invention, the method for constructing the representative molecular model of the rubber may include: using Build Polymers, calling styrene and butadiene repeating units in a ratio of 12 parts by mass of styrene, 29 parts by mass of trans-1,4-butadiene, 3 parts by mass of cis-1,4-butadiene and 6 parts by mass of 1,2-butadiene, to construct a random copolymer styrene butadiene rubber single-chain molecular model; using BuildPolymer, calling amorphous crystal cells of natural rubber, to construct a natural rubber single-chain molecular model; using the Amorphous Cell module to call 3 parts by mass of the random copolymer styrene butadiene rubber single-chain molecular model and 7 parts by mass of natural rubber single-chain molecular model to construct the representative molecular model of the rubber.
[0048] As an embodiment of the present invention, after the rubber representative molecular model is constructed, optimization processing is also included. The steps and operating conditions of the optimization processing can be specifically consistent with the optimization processing after the asphalt molecular group model is constructed, and will not be repeated here.
[0049] After obtaining the asphalt molecular group model and the rubber representative molecular model, the present invention constructs the rubber asphalt molecular group model based on the asphalt molecular group model and the rubber representative molecular model. As an implementation method of the present invention, specifically, the Amorphous Cell module is used to import the rubber representative molecular model into the asphalt molecular group model to construct the rubber asphalt molecular group model.
[0050] As an embodiment of the present invention, after the rubber asphalt molecular group model is constructed, it also includes optimization processing. The steps and operating conditions of the optimization processing can be specifically consistent with the optimization processing after the asphalt molecular group model is constructed, and will not be repeated here.
[0051] As an embodiment of the present invention, the rubber asphalt molecular group model also includes rationality verification after the optimization process is completed. The rationality verification specifically includes: deriving the rubber asphalt molecular group model with a density of 1 to 1.1 g / cm at 25°C. 3 , which is consistent with the density range of rubber asphalt, and the rubber asphalt molecular group model has the rationality to represent the properties of rubber asphalt. The present invention can ensure that the constructed rubber asphalt molecular group model can represent the macroscopic rubber asphalt at the molecular scale through rationality verification, which is conducive to the expression of the physical properties of rubber asphalt in molecular scale simulation calculations and improves the reliability and representativeness of simulation calculations.
[0052] The present invention constructs a steel slag representative molecular model, and then constructs a steel slag-rubber asphalt bonding interface molecular model based on the steel slag representative molecular model and the rubber asphalt molecular group model. As an implementation method of the present invention, specifically, a tricalcium silicate unit cell model and a dicalcium silicate unit cell model are imported, and then the surfaces of the tricalcium silicate unit cell and the dicalcium silicate unit cell are cut, and the surface energy of the tricalcium silicate unit cell and the dicalcium silicate unit cell is released using the Forcite module Calculation tool, and the lower atoms in the tricalcium silicate unit cell and the dicalcium silicate unit cell (specifically, a layer of atoms away from the interface direction) are fixed, and the steel slag representative molecular model is obtained by using Build.
[0053] As an embodiment of the present invention, after the steel slag representative molecular model is constructed, it also includes optimization processing. The steps and operating conditions of the optimization processing can be specifically consistent with the optimization processing after the asphalt molecular group model is constructed, and will not be repeated here.
[0054] As an embodiment of the present invention, the steel slag representative molecular model also includes rationality verification after the optimization process is completed. The rationality verification specifically includes: using the Mechanical Properties module to calculate the elastic modulus and Poisson's ratio of the steel slag representative molecular model after the optimization process, and the calculated elastic modulus and Poisson's ratio are consistent with the elastic modulus and Poisson's ratio obtained from the steel slag test, and the steel slag representative molecular model has the rationality of representing the properties of steel slag. As an embodiment of the present invention, the calculated elastic modulus and Poisson's ratio are consistent with the elastic modulus and Poisson's ratio obtained from the steel slag test, specifically, for example, the elastic modulus obtained from the steel slag test is 17.99~100.17GPa, if the calculated elastic modulus is within the aforementioned range, the two are consistent; for another example, the Poisson's ratio obtained from the steel slag test is 0.22~0.37, if the calculated Poisson's ratio is within the aforementioned range, the two are consistent. The present invention can ensure, through rationality verification, that the constructed steel slag representative molecular model can represent the macroscopic steel slag to a certain extent, which is beneficial to the expression of the physical properties of steel slag in molecular scale simulation calculations and improves the reliability and representativeness of the simulation calculations.
[0055] As an embodiment of the present invention, after obtaining the rubber asphalt molecular group model and the steel slag representative molecular model, the rubber asphalt molecular group model and the steel slag representative molecular model are combined using Build Layers to construct the steel slag-rubber asphalt bonding interface molecular model.
[0056] As an embodiment of the present invention, after the steel slag-rubber asphalt bonding interface molecular model is constructed, it also includes optimization processing. The steps and operating conditions of the optimization processing can be specifically consistent with the optimization processing after the asphalt molecular group model is constructed, and will not be repeated here.
[0057] After obtaining the steel slag-rubber asphalt bonding interface molecular model, the present invention applies tensile stress to the steel slag-rubber asphalt bonding interface molecular model in a direction perpendicular to the steel slag-rubber asphalt bonding interface, so that the steel slag-rubber asphalt bonding interface molecular model is destroyed until a stable state is reached, thereby obtaining a destruction model. As one embodiment of the present invention, when tensile stress is applied to the steel slag-rubber asphalt bonding interface molecular model, the magnitude, direction and point of action of the tensile stress are fixed; the stable state described in the present invention specifically refers to a state in which the rubber asphalt remaining on the steel slag surface no longer decreases after the overall model is destroyed by the tensile stress as time continues to increase, that is, the separated rubber asphalt no longer increases. As one embodiment of the present invention, when tensile stress is applied to the steel slag-rubber asphalt bonding interface molecular model, it can be adjusted and selected with reference to the stress range of the macroscopic pull-out test, such as based on the macroscopic pull-out test, according to the unit area (mm 2) stress range, the unit area at the molecular scale can be obtained The magnitude of stress is adjusted and selected by comprehensively considering the scale effect to ensure the true expression of macroscopic mechanical behavior in the simulation calculation at the molecular scale.
[0058] After obtaining the failure model, the present invention performs dynamic calculations on the steel slag-rubber asphalt bonding interface molecular model and the failure model to obtain the molecular dynamics indicators of the steel slag-rubber asphalt bonding interface molecular model, wherein the molecular dynamics indicators include interaction energy density, radial distribution function and radial distribution concentration; the bonding strength between steel slag and rubber asphalt is determined according to the molecular dynamics indicators. As an embodiment of the present invention, specifically, the dynamic calculation is performed using the Forcite module Dynamics tool to select the COMPASS II force field under the canonical ensemble NVT ensemble. The present invention performs dynamic calculations on the steel slag-rubber asphalt bonding interface molecular model before and after the tensile stress, and obtains the molecular dynamics indicators on this basis, thereby determining the bonding strength between steel slag and rubber asphalt.
[0059] The interaction energy density of the present invention is used to characterize the potential energy density between two molecules in a non-bonded interaction molecular system; the interaction energy density between steel slag and rubber asphalt can be used to determine the strength of the interaction between steel slag and rubber asphalt; the greater the interaction energy density, the greater the interaction strength per unit area between the two, and the better the bonding between steel slag and rubber asphalt. As an embodiment of the present invention, the interaction energy density can be obtained according to Formula 1 and Formula 2:
[0060] E i =E AB -E A -E B Formula 1;
[0061] E i-ρ =|E i / S| Formula 2;
[0062] Among them, E i is the interaction energy between molecules A and B (kcal); E AB is the molecular potential energy of the mixture of molecules A and B (kcal); E A is the molecular potential energy of molecule A (kcal); E B is the molecular potential energy of molecule B (kcal); S is the interfacial area E i-ρ is the interaction energy density between molecules A and B.
[0063] The radial distribution function of the present invention is used to characterize the accumulation and distribution of the internal structural molecules of the material; the location of the radial distribution function peak can be used to determine the type of interaction between the steel slag representative molecule and the rubber asphalt molecular group model, including hydrogen bonding, van der Waals force, etc.; the larger the radial distribution function peak, the stronger the type of interaction, and the better the bonding effect between the steel slag and the rubber asphalt. As an embodiment of the present invention, the radial distribution function is specifically shown in Formula 3:
[0064]
[0065] Among them, g A-B (r) is the probability of molecule B appearing when the distance from molecule A is r; N A is the number of molecules A; N B is the number of molecules B; r is the distance between molecules A and B N AB is the number of molecules A and B; V is the spatial volume of the system I is the Ith molecule, J is the Jth molecule; r Ai is the distance from the first molecule A to the molecule B; r Aj is the distance from the Jth molecule A to molecule B.
[0066] The radial distribution concentration of the present invention is used to characterize the relative spatial distribution of two materials in a molecular system. The distribution of rubber asphalt on the steel slag surface can be judged by the shape and position of the radial distribution concentration peak, and then the degree of adhesion of rubber asphalt on the steel slag surface can be judged. When the peak position of the radial distribution concentration of rubber asphalt on the steel slag surface is closer to This indicates that the rubber asphalt is accumulated on the surface of the steel slag in large quantities, and the bonding effect is good; on the contrary, when the peak position of the radial distribution concentration of the rubber asphalt on the surface of the steel slag is greater than This indicates that the rubber asphalt is gathered at a position far away from the steel slag surface, and the bonding effect between the two is poor. As an embodiment of the present invention, the radial distribution concentration can be obtained according to formula 4:
[0067]
[0068] Among them, RC A is the radial distribution concentration; N A is the number of molecules A; V is the spatial volume of the system c s is the concentration of the system (%).
[0069] After obtaining the failure model, the present invention measures the residual thickness of rubber asphalt on the steel slag surface in the failure model as the steel slag-rubber asphalt adhesion interface thickness, and determines the failure type of the steel slag-rubber asphalt interface according to the steel slag-rubber asphalt adhesion interface thickness. As an embodiment of the present invention, the steel slag-rubber asphalt adhesion interface thickness is recorded as H, when H>0, the failure type of the steel slag-rubber asphalt interface is bonding failure; when H=0, the failure type of the steel slag-rubber asphalt interface is adhesion failure.
[0070] After determining the bonding strength between steel slag and rubber asphalt, and the damage type of the steel slag-rubber asphalt interface, the present invention implements the evaluation of the steel slag-rubber asphalt bonding interface based on the bonding strength between the steel slag and rubber asphalt, and the damage type of the steel slag-rubber asphalt interface.
[0071] The present invention realizes the interface evaluation of steel slag-rubber asphalt by molecular dynamics simulation technology, which can accurately restore the molecular contact relationship of the steel slag-rubber asphalt interface, greatly improving the objectivity of the evaluation; the present invention uses molecular dynamics simulation technology to measure the rubber asphalt after the steel slag-rubber asphalt is destroyed after the load, obtain the thickness of the residual rubber asphalt at the molecular scale, and define this part of the residual rubber asphalt at the molecular scale as the "adhesion interface", that is, the transition area between the rubber asphalt and the steel slag. This part of the rubber asphalt will form a layer of rubber asphalt film after fully contacting the steel slag, which plays a bonding role between the steel slag and the rubber asphalt. By measuring the thickness of the steel slag-rubber asphalt adhesion interface (H), when H>0, the steel slag-rubber asphalt interface failure type is adhesion failure, indicating that after the steel slag-rubber asphalt is subjected to tension, the interaction between the two is strong enough to retain part of the rubber asphalt as the "adhesion interface"; when H=0, the steel slag-rubber asphalt interface failure type is adhesion failure, indicating that after the steel slag-rubber asphalt is subjected to tension, the hydrogen bonding between the steel slag and the rubber asphalt is not enough to retain the rubber asphalt molecules, resulting in all the rubber asphalt being peeled off the steel slag surface by external force. By judging the type of steel slag-rubber asphalt interface failure, that is, clarifying whether it is adhesion failure or bonding failure, we can theoretically guide the macro conditions such as the mix ratio design of steel slag rubber asphalt mixture and the control of the molding environment; and it can serve as a theoretical basis for the targeted material design of steel slag rubber asphalt mixture, improving the material design efficiency of steel slag rubber asphalt mixture and the realization of functionality.
[0072] As an embodiment of the present invention, the steel slag-rubber asphalt bonding interface molecular model of the present invention can be replaced by a steel slag-water-rubber asphalt bonding interface molecular model or a steel slag-inorganic salt aqueous solution-rubber asphalt bonding interface molecular model; when the steel slag-water-rubber asphalt bonding interface molecular model is adopted, the operation is performed with reference to the above-mentioned method for constructing the steel slag-rubber asphalt bonding interface molecular model, except that water molecules are introduced to construct a steel slag-water-rubber asphalt bonding interface molecular model, that is, it is expanded into a steel slag-water-rubber asphalt three-phase bonding interface molecular model, so as to realize the research and evaluation of the steel slag-rubber asphalt bonding interface under the condition of water; when the steel slag-inorganic salt aqueous solution-rubber asphalt bonding interface molecular model is adopted, the operation is performed with reference to the above-mentioned method for constructing the steel slag-rubber asphalt bonding interface molecular model, except that water molecules and inorganic salt molecules are introduced to construct a steel slag-inorganic salt aqueous solution-rubber asphalt bonding interface molecular model, that is, it is expanded into a steel slag-inorganic salt aqueous solution-rubber asphalt three-phase bonding interface molecular model, so as to realize the research and evaluation of the steel slag-rubber asphalt bonding interface under the condition of inorganic salt aqueous solution.
[0073] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0074] Example 1
[0075] Step 1: Construct asphalt molecular group model: Use the Amorphous Cell module to combine the molecular models of asphaltene, colloid, saturated fraction and aromatic fraction, and adjust the proportion of each component molecular model according to the proportion of the four components of the matrix asphalt to construct the asphalt molecular group model; wherein the proportion of the four components of the matrix asphalt can be obtained by the T0618-1993 asphalt chemical component test (four-component method) specified in the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011);
[0076] Then, the asphalt molecular group model is optimized, and the optimization process includes sequentially performing geometry optimization, annealing and dynamic optimization; the geometry optimization specifically includes: using the GeometryOptimization tool of the Forcite module to perform geometry optimization under the COMAPASS II force field until the energy convergence is stable; the annealing process specifically includes: using the Anneal tool of the Forcite module to perform annealing under the NVE ensemble, with 100,000 iterations; the dynamic optimization specifically includes: performing 100ps of dynamic optimization at a temperature of 1500K, and then performing 200ps of dynamic optimization at a temperature of 298K;
[0077] Step 2: Constructing a representative molecular model of rubber: 1) Using BuildPolymers, call styrene and butadiene repeating units in a ratio of 12 parts by mass of styrene, 29 parts by mass of trans-1,4-butadiene, 3 parts by mass of cis-1,4-butadiene, and 6 parts by mass of 1,2-butadiene to construct a random copolymer styrene butadiene rubber single chain molecular model; 2) Using BuildPolymer, call amorphous crystal cells of natural rubber to construct a natural rubber single chain molecular model; 3) Use the Amorphous Cell module to call 3 parts by mass of random copolymer styrene butadiene rubber single chain molecular model and 7 parts by mass of natural rubber single chain molecular model to construct a rubber representative molecular model, and then optimize the rubber representative molecular model according to the method in step 1;
[0078] Step 3: Constructing a rubber asphalt molecular group model: Using the Amorphous Cell module, the rubber representative molecular model is imported into the asphalt molecular group model to construct a rubber asphalt molecular group model. Then, the rubber asphalt molecular group model is optimized according to the method in step 1, and then the rationality of the optimized rubber asphalt molecular group model is verified. The rationality verification specifically includes: deriving the rubber asphalt molecular group model with a density of 1 to 1.1 g / cm at 25°C. 3 , which is consistent with the density range of rubber asphalt, and the rubber asphalt molecular group model is reasonable in representing the properties of rubber asphalt;
[0079] Step 4: Construct a representative molecular model of steel slag: import the unit cell model of tricalcium silicate and dicalcium silicate, cut the unit cell surface, use the Calculation tool of the Forcite module to release the surface energy of the unit cell, fix the lower atoms in the unit cell, and use Build to construct a representative molecular model of steel slag; then optimize the representative molecular model of steel slag according to the method in step 1, and then verify the rationality of the optimized representative molecular model of steel slag. The rationality verification specifically includes: using Mechanical The Properties module calculates the elastic modulus and Poisson's ratio of the representative molecular model of the optimized steel slag, and the elastic modulus of dicalcium silicate and tricalcium silicate are calculated to be 81.6099 GPa, 31.4568 GPa, 0.2721 and 0.2755, which are within the range of the elastic modulus (17.99-100.17 GPa) and Poisson's ratio (0.22-0.37) obtained from the steel slag test, indicating that the two are consistent, and the representative molecular model of the steel slag is reasonable to represent the properties of the steel slag;
[0080] Figure 1 is a schematic diagram of the representative molecular model of steel slag. Figure 1 Two representative molecular models of steel slag are specifically given, namely the dicalcium silicate model and the tricalcium silicate model, of which the left side is the single cell model and the right side is the crystal super cell model;
[0081] Step 5: Constructing the molecular model of steel slag-rubber asphalt bonding interface: Use Build Layers to combine the rubber asphalt molecular group model obtained in step 3 with the steel slag representative molecular model obtained in step 4 to construct the steel slag-rubber asphalt bonding interface molecular model, and then optimize the steel slag-rubber asphalt bonding interface molecular model according to the method in step 1;
[0082] Figure 2 Schematic diagram of the molecular model of the steel slag-rubber asphalt bonding interface, where the upper colored irregular model is rubber asphalt, and the lower red-green regular model is the steel slag representative molecular model;
[0083] Step 6: Applying tensile stress to the steel slag-rubber asphalt bonding interface molecular model: applying tensile stress in a direction perpendicular to the steel slag-rubber asphalt bonding interface to destroy the steel slag-rubber asphalt bonding interface molecular model until it reaches a stable state, thereby obtaining a destruction model;
[0084] Figure 3 The schematic diagram of the behavior change of steel slag-rubber asphalt molecules under tensile stress, that is, the schematic diagram of the process of steel slag-rubber asphalt molecules being destroyed by tensile load along the Z direction. From left to right, it can be roughly divided into three stages: stress deformation (a~c)-destruction (d~f)-stability (g).
[0085] Step 7: Perform dynamic calculation on the molecular model of the steel slag-rubber asphalt bonding interface before and after the tensile stress: Use the Forcite module Dynamics tool to select the COMPASS II force field under the canonical ensemble NVT ensemble to perform dynamic calculation, obtain the molecular dynamics index of the steel slag-rubber asphalt bonding interface molecular model, and determine the bonding strength between the steel slag and the rubber asphalt according to the molecular dynamics index; wherein the molecular dynamics index includes the interaction energy density (obtained according to Formula 1 and Formula 2), the radial distribution function (Formula 3) and the radial distribution concentration (Formula 4);
[0086] Step 8: Measure the residual thickness of rubber asphalt on the steel slag surface in the molecular model of the steel slag-rubber asphalt bonding interface after tensile stress, and use it as the thickness of the steel slag-rubber asphalt adhesion interface to obtain On this basis, the failure type of the steel slag-rubber asphalt interface was determined. Therefore, it is judged that the failure type of the steel slag-rubber asphalt interface is bonding failure.
[0087] As a control group, the above-mentioned similar simulation calculation was performed on the molecular model of the basalt-rubber asphalt bonding interface, and H=0 was obtained, indicating that the type of damage at the basalt-rubber asphalt interface was adhesion damage. It can be judged that steel slag has a better bonding effect on rubber asphalt than basalt.
[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for evaluating the bonding interface of steel slag and rubber asphalt, comprising the following steps: respectively constructing an asphalt molecular group model and a rubber representative molecular model, and constructing a rubber asphalt molecular group model according to the asphalt molecular group model and the rubber representative molecular model; Constructing a steel slag representative molecular model, and constructing a steel slag-rubber asphalt bonding interface molecular model based on the steel slag representative molecular model and the rubber asphalt molecular group model; Applying tensile stress to the steel slag-rubber asphalt bonding interface molecular model in a direction perpendicular to the steel slag-rubber asphalt bonding interface, so that the steel slag-rubber asphalt bonding interface molecular model is destroyed until a stable state is reached, thereby obtaining a destruction model; Performing dynamic calculation on the steel slag-rubber asphalt bonding interface molecular model and the destruction model to obtain molecular dynamics indicators of the steel slag-rubber asphalt bonding interface molecular model, wherein the molecular dynamics indicators include interaction energy density, radial distribution function and radial distribution concentration; determining the bonding strength between steel slag and rubber asphalt according to the molecular dynamics indicators; Measuring the residual thickness of rubber asphalt on the surface of steel slag in the failure model as the thickness of the steel slag-rubber asphalt adhesion interface, and determining the failure type of the steel slag-rubber asphalt interface according to the thickness of the steel slag-rubber asphalt adhesion interface; The steel slag-rubber asphalt bonding interface is evaluated according to the bonding strength between the steel slag and rubber asphalt and the damage type of the steel slag-rubber asphalt interface.
2. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: The thickness of the steel slag-rubber asphalt adhesion interface is recorded as H. When H>0, the failure type of the steel slag-rubber asphalt interface is bonding failure; when H=0, the failure type of the steel slag-rubber asphalt interface is adhesion failure.
3. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: After the asphalt molecular group model, rubber representative molecular model, rubber asphalt molecular group model, steel slag representative molecular model and steel slag-rubber asphalt bonding interface molecular model are constructed, they are independently optimized. The optimization process includes geometric optimization, annealing treatment and kinetic optimization in sequence.
4. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 3, characterized in that: The geometry optimization includes: using the Geometry Optimization tool of the Forcite module to perform geometry optimization under the COMAPASS II force field until the energy converges and stabilizes; The annealing process includes: using the Anneal tool of the Forcite module to perform annealing under the NVE ensemble, and the number of iterations is not less than 100,000 times; The kinetic optimization includes: performing kinetic optimization for at least 100 ps at a temperature of 1500 K, and then performing kinetic optimization for at least 200 ps at a temperature of 298 K.
5. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 3 or 4, characterized in that: After the optimization process of the rubber asphalt molecular group model is completed, the rationality verification is also included. The rationality verification includes: deriving the density of the rubber asphalt molecular group model at 25°C is 1-1.1g / cm 3 , which is consistent with the density range of rubber asphalt. The rubber asphalt molecular group model is reasonable in representing the properties of rubber asphalt.
6. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 3 or 4, characterized in that: After the optimization process is completed, the steel slag representative molecular model also includes rationality verification, and the rationality verification includes: using the MechanicalProperties module to calculate the elastic modulus and Poisson's ratio of the steel slag representative molecular model after the optimization process, and the calculated elastic modulus and Poisson's ratio are consistent with the elastic modulus and Poisson's ratio obtained from the steel slag test, and the steel slag representative molecular model has the rationality to represent the properties of steel slag.
7. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: The interaction energy density is obtained according to equation 1 and equation 2: E i = E AB -E A -E B Formula 1; E i-ρ =|E i / S| Formula 2; Among them, E i is the interaction energy between molecules A and B; E AB is the molecular potential energy of the mixture of molecules A and B; E A is the molecular potential energy of molecule A; E B is the molecular potential energy of molecule B; S is the interface area; E i-ρ is the interaction energy density between molecules A and B.
8. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: The radial distribution function is shown in Formula 3: Among them, g A-B (r) is the probability of molecule B appearing when the distance from molecule A is r; N A is the number of molecules A; N B is the number of molecules B; r is the distance between molecules A and B; N AB is the number of molecules A and B; V is the spatial volume of the system; I is the Ith molecule, J is the Jth molecule; r Ai is the distance from the first molecule A to molecule B; r Aj is the distance from the Jth molecule A to molecule B.
9. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: The radial distribution concentration is obtained according to Formula 4: Among them, RC A is the radial distribution concentration; N A is the number of molecules A; V is the spatial volume of the system; c s is the concentration of the system.
10. The method for evaluating the steel slag-rubber asphalt bonding interface according to claim 1, characterized in that: The steel slag-rubber asphalt bonding interface molecular model is replaced by a steel slag-water-rubber asphalt bonding interface molecular model or a steel slag-inorganic salt aqueous solution-rubber asphalt bonding interface molecular model.