CN-121999925-A - Method for simulating diffusion of dynamic coefficient characterization regenerant in aged asphalt

CN121999925ACN 121999925 ACN121999925 ACN 121999925ACN-121999925-A

Abstract

The invention provides a method for simulating the diffusion of a regenerant with dynamic coefficient characterization in aged asphalt, which relates to the technical field of road material regeneration, and comprises the steps of measuring dynamic viscosity of the regenerant at a plurality of preset temperatures, calculating kinematic viscosity, and performing temperature viscosity conversion on the kinematic viscosity to obtain characteristic parameters of the regenerant; the method comprises the steps of constructing a temperature field changing along with time, calculating the kinematic viscosity of the regenerant changing along with time according to the temperature field changing along with time and characteristic parameters of the regenerant, calculating the kinematic viscosity of the regenerant changing along with time, calculating the diffusion coefficient of the regenerant changing along with time in aged asphalt, constructing a three-dimensional space calculation domain, setting initial concentration distribution and zero flux boundary conditions of the regenerant in the three-dimensional space calculation domain, substituting the diffusion coefficient of the regenerant changing along with time in the aged asphalt into a three-dimensional expansion equation of a Fick second law, and solving the diffusion concentration distribution of the regenerant changing along with time in the aged asphalt by adopting a finite difference method.

Inventors

REN MINDA
WU YUNHAO
MA LINHUA
REN QINGQING
HAN QINGHAO
Pei Zian
HE ZIYI

Assignees

内蒙古工业大学

Dates

Publication Date: 20260508
Application Date: 20260109

Claims (10)

1. A method for simulating diffusion of a regenerant with dynamic coefficient characterization in aged asphalt is characterized by comprising the following steps: measuring dynamic viscosity of the regenerant at a plurality of preset temperatures, calculating the kinematic viscosity according to the dynamic viscosity and the regenerant density, and performing temperature viscosity conversion on the kinematic viscosity to obtain characteristic parameters of the regenerant; Constructing a time-varying temperature field comprising a heating stage, a constant temperature stage and a cooling stage to simulate the temperature variation of the regenerant in the construction process of the aged asphalt; Calculating the time-varying kinematic viscosity of the regenerant according to the time-varying temperature field and the characteristic parameters of the regenerant, and calculating the time-varying kinematic viscosity of the regenerant according to the time-varying kinematic viscosity of the regenerant and the regenerant density; Calculating the diffusion coefficient of the regenerant in the aged asphalt along with the time change by combining the temperature field along with the time change of the dynamic viscosity of the regenerant along with the time change; Constructing a three-dimensional space calculation domain, and setting initial concentration distribution of a regenerant and a zero flux boundary condition in the three-dimensional space calculation domain; Substituting the diffusion coefficient of the regenerant in the aged asphalt, which changes with time, into a three-dimensional expansion form equation of the Fick second law, and solving by adopting a finite difference method to obtain the diffusion concentration distribution of the regenerant in the aged asphalt, which changes with time.
2. The method for simulating the diffusion of the dynamic coefficient-characterized regenerant in aged asphalt according to claim 1, wherein said dynamic viscosity is measured by a rotational viscometer method; and the characteristic parameters of the regenerant are calculated according to the kinematic viscosity by adopting a Walter equation.
3. The method for simulating diffusion of the regenerant with the dynamic coefficient representation in the aged asphalt according to claim 1, wherein the temperature rise stage is linear temperature rise and is used for simulating the time-varying process of the regenerant in asphalt mixture construction; The constant temperature stage is used for simulating the process of changing the regenerant with time in the transportation of the asphalt mixture; the cooling stage is nonlinear cooling and is used for simulating the time-varying process of the regenerant in asphalt mixture paving.
4. The method for simulating the diffusion of a regenerant characterized by a dynamic coefficient in an aged asphalt according to claim 1, wherein said step of calculating the kinematic viscosity of the regenerant over time comprises: calculating the motion viscosity of the regenerant along with the time according to the temperature field along with the time and the characteristic parameters of the regenerant by adopting a Walther equation, wherein the calculation formula is as follows: ; Wherein: For the kinematic viscosity of the regenerant over time, For the temperature of the regenerant over time, And Is a characteristic parameter of the regenerant.
5. The method for simulating diffusion of a regenerant characterized by a dynamic coefficient in an aged asphalt according to claim 4, wherein said step of calculating the diffusion coefficient of the regenerant in the aged asphalt over time comprises: The Stokes-Einstein equation is adopted, and the time-varying diffusion coefficient of the regenerant in the aged asphalt is calculated by combining the time-varying temperature field and the time-varying dynamic viscosity of the regenerant, wherein the calculation formula is as follows: ; Wherein: To regenerate the diffusion coefficient of the regenerant in aged asphalt over time, =1.387×10 -23 J/K is the boltzmann constant, For the temperature of the regenerant over time, For the dynamic viscosity of the regenerant over time, Is the molecular radius.
6. The method for simulating diffusion of the regenerant with dynamic coefficient representation in aged asphalt according to claim 1, wherein the three-dimensional expansion form equation of the second law of fick is obtained by expanding the second law of fick into a three-dimensional form, and the calculation formula is as follows: ; Wherein: In order to change the diffusion coefficient of the regenerant in the aged asphalt along the time, x, y and z are diffusion distances in three directions, In order for the diffusion time to be within, Is the diffusion concentration of the regenerant in aged asphalt with time.
7. The method for simulating diffusion of the regenerant with dynamic coefficient representation in the aged asphalt according to claim 6, wherein the step of solving the diffusion concentration distribution of the regenerant in the aged asphalt with time by adopting a finite difference method comprises the following steps: dispersing the space domain by adopting a central difference method to obtain a space domain dispersion equation; dispersing the time domain by adopting a display Euler method to obtain a time domain dispersion equation; Combining the space domain discrete equation and the time domain discrete equation to obtain a total discrete equation, wherein the calculation formula is as follows: ; Wherein: For the next time space point Is used for the regeneration of the water-soluble catalyst, For the current time space point Is used for the regeneration of the water-soluble catalyst, In order for the diffusion coefficient to be the same, For the time step size of the time step, For the rate of change of the regenerant concentration in the x-direction, For the rate of change of the regenerant concentration in the y-direction, Is the rate of change of the regenerant concentration in the z-direction; and obtaining the diffusion concentration distribution of the regenerant in the aged asphalt, which changes with time, by iteratively solving the total discrete equation.
8. A dynamic temperature field based regenerant diffusion prediction system in aged asphalt comprising: The measuring module is used for measuring the dynamic viscosity of the regenerant at a plurality of preset temperatures, calculating the kinematic viscosity according to the dynamic viscosity and the regenerant density, and carrying out temperature viscosity conversion on the kinematic viscosity to obtain characteristic parameters of the regenerant; the temperature field construction module is used for constructing a time-varying temperature field comprising a heating stage, a constant temperature stage and a cooling stage so as to simulate the temperature variation process of the regenerant; The dynamic viscosity calculation module is used for calculating the dynamic viscosity of the regenerant along with the time according to the temperature field along with the time and the characteristic parameters of the regenerant, and calculating the dynamic viscosity of the regenerant along with the time according to the dynamic viscosity of the regenerant along with the time and the density of the regenerant; the diffusion coefficient calculation module is used for calculating the diffusion coefficient of the regenerant in the aged asphalt along with the time change by combining the temperature field along with the time change and the dynamic viscosity of the regenerant along with the time change; the calculation domain construction module is used for constructing a three-dimensional space calculation domain, and setting initial concentration distribution of the regenerant and a zero flux boundary condition in the three-dimensional space calculation domain; and the diffusion concentration distribution calculation module is used for substituting the diffusion coefficient of the regenerant, which changes with time, in the aged asphalt into a three-dimensional expansion form equation of the Fick second law, and solving the diffusion concentration distribution of the regenerant, which changes with time, in the aged asphalt by adopting a finite difference method.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method for simulating the diffusion of the regenerant characterized by the dynamic coefficient according to any one of claims 1 to 7 in aged asphalt.
10. A computer readable storage medium having stored thereon a computer program, wherein the computer program, when executed by a processor, implements the steps of the method for simulating diffusion of a rejuvenating agent characterized by a dynamic coefficient according to any one of claims 1 to 7 in aged asphalt.

Description

Method for simulating diffusion of dynamic coefficient characterization regenerant in aged asphalt Technical Field The invention relates to the technical field of road material regeneration, in particular to a method for simulating diffusion of a dynamic coefficient-characterized regenerant in aged asphalt. Background Along with the entering of a large number of asphalt pavements into maintenance and repair periods, the recycling of waste asphalt mixtures has become a key subject for realizing sustainable development in the field of pavement engineering. The regenerant can restore the rheological property of the aged asphalt, so that the road performance of the regenerated asphalt mixture is improved, and the economic and environmental benefits are obvious, so that the application of the regenerant has become one of the core means of the regeneration technology. The regenerant is used for supplementing the light components lost in the aged asphalt, and the process is needed to be realized through the diffusion of the regenerant in the aged asphalt. However, existing regenerant diffusion behavior prediction schemes reduce the diffusion coefficient to a constant. In practice, the regeneration process of the asphalt mixture comprises a plurality of stages of mixing, transportation, paving and the like, the temperature field undergoes significant linear temperature rise, constant temperature maintenance and nonlinear temperature reduction dynamic changes, the diffusion coefficient is extremely sensitive to temperature, and the fixed diffusion coefficient is adopted for prediction, so that the calculated result is seriously deviated from the actual engineering, the accurate blending of the regenerant and the optimal control of the construction process cannot be accurately guided, and the regeneration effect and the engineering quality improvement are restrained. Disclosure of Invention The invention aims to provide a method for simulating diffusion of a regenerant with dynamic coefficient characterization in aged asphalt, which aims to solve the problems that the existing regenerant diffusion behavior prediction scheme in the background art simplifies the diffusion coefficient into a constant, which can cause serious deviation between a calculation result and engineering reality and can not accurately guide accurate blending of the regenerant and optimization control of a construction process. The invention provides a method for simulating the diffusion of a regenerant in aged asphalt, which is characterized by dynamic coefficients, and comprises the following steps of measuring dynamic viscosity of the regenerant at a plurality of preset temperatures, calculating the dynamic viscosity according to the dynamic viscosity and the density of the regenerant, converting the dynamic viscosity to temperature viscosity to obtain characteristic parameters of the regenerant, constructing a time-varying temperature field comprising a heating stage, a constant temperature stage and a cooling stage to simulate the temperature variation of the regenerant in the construction process of the aged asphalt, calculating the dynamic viscosity of the regenerant, which varies with time, according to the time-varying temperature field and the characteristic parameters of the regenerant, calculating the dynamic viscosity of the regenerant, which varies with time, according to the dynamic viscosity of the regenerant, which varies with time, in combination with the time-varying temperature field and the dynamic viscosity of the regenerant, calculating the diffusion coefficient of the regenerant, which varies with time in the aged asphalt, constructing a three-dimensional space calculation domain, setting initial concentration distribution of the regenerant and zero boundary conditions in the three-dimensional space calculation domain, substituting the diffusion coefficient of the regenerant, which varies with time in the aged asphalt, into a second law of time-varying concentration distribution of the aged asphalt, and obtaining the aged asphalt by adopting a three-dimensional expansion law of a finite difference expansion law of the time-varying concentration distribution of the regenerant. Optionally, the dynamic viscosity is measured by a rotational viscometer method, and the characteristic parameter of the regenerant is calculated according to the dynamic viscosity by adopting a Walter equation. Optionally, the temperature rising stage is linear temperature rising and is used for simulating the time-varying process of the regenerant in asphalt mixture construction, the constant temperature stage is used for simulating the time-varying process of the regenerant in asphalt mixture transportation, and the temperature reducing stage is nonlinear temperature reducing and is used for simulating the time-varying process of the regenerant in asphalt mixture paving. Optionally, the step of calculating the time-varying kinematic viscosity of th