CN110491452A - Performance of modified bitumen prediction technique based on molecular dynamics simulation - Google Patents

Abstract

The present invention is a kind of prediction technique of performance of modified bitumen based on molecular dynamics simulation, belongs to modified asphalt technology field.It mainly solves the problems, such as do not setting up relationship between software analog result and Pavement Performance of Modified Asphalt with molecular dynamics simulation software fashion at present.The present invention first measures density, needle penetration, softening point and the ductility of SBS modified pitch, the correlation of analytic density and softening point, needle penetration respectively, then SBS modified pitch co-mixing system model is established by molecular dynamics software, line density of going forward side by side calculates and stretches simulation, compare simulation and test result, optimize molecular simulation algorithm, predicts three norms, three norms experiment is carried out, finally to verify the consistency of simulation with experimental result.Method provided by the invention can quickly and accurately predict the three norms of SBS modified pitch, so as to effectively instruct the production practices of SBS modified pitch, simultaneously to the using effect for improving SBS modified pitch, it is of great significance to the pavement engineering for building excellent.

Description

Performance of modified bitumen prediction technique based on molecular dynamics simulation

Technical field

The present invention is a kind of prediction technique of performance of modified bitumen based on molecular dynamics simulation, belongs to modified pitch skill Art field.

Background technique

Highway provides the infrastructure of convenience as one for the public, is always the key project of nation-building, is weighing apparatus Measure one of a national economy level and mark of state of development.High speed development and construction by more than 30 years, end in Year ends 2018, national total kilometrage are up in 484.65 ten thousand.The main road surface types of highway in China are asphalt concrete pavement at present, Account for about the 80% of the highway in China road surface gross area.In order to improve the quality level of bituminous pavement, excellent bituminous pavement is built, it is right The detection of asphalt softening point, ductility and needle penetration be it is essential, one side needle penetration, softening point and ductility be evaluation pitch It must be detected during the important quality index and asphalt production of material pavement performance, pitch sale and road construction etc. On the other hand index also facilitates and compares with by domestic pitch detection data with external corresponding bitumen technology specification.China's mesh It is preceding still to continue to use asphalt softening point measuring method (ring and ball method) (GBT4507-2014), effecting determination of asphalt ductility method (GBT4508- respectively 2010), Asphalt Penetration measuring method (GBT4509-2010) measures softening point, ductility and the needle penetration of pitch respectively, all referring to mark Detection needs various asphalt detection device, and sample is sticky, complicated for operation, there is pollution environment, and detection cycle is long, long-term existence inspection Survey lags behind demand, and asphalt quality monitors during drastically influencing.

Meanwhile with the continuous improvement required road quality, matrix pitch is difficult to meet the requirements again, therefore modified pitch It comes into being and develops quickly, and s-B-S (SBS) is used as thermoplastic elastomer modified dose of one kind, due to Its excellent performance largely comes into operation.System becomes more complicated after SBS is added in pitch, and originally the rheology of system is special Property is also significantly changed, then will be become further with the performance of traditional experimental method accurate evaluation modified pitch It is difficult.

In conclusion the measurement experiment of the softening point for the pitch always continued to use, ductility and needle penetration is there are shortcomings, because This, needs to develop a kind of detection technique that can while quick and precisely detect a variety of SBS Properties of Modified Asphalt, and with science and technology The fast development in epoch, in order to preferably recognize asphalt material, people start to turn to microcosmic level, modified pitch from macroscopic view Macro property it is again closely related with the microstructure of pitch, just propose and a kind of predict that SBS changes with molecular dynamics simulation The thinking of property asphalt softening point, ductility and needle penetration.

Molecular Dynamics method is a kind of computer simulation method that Macro Problems are solved in atom, molecular level, he is logical Cross solution Equation of Classical Mechanics, using the method in the field of force, simulated system with time change evolutionary process.In addition to molecular force field Described static nature potential energy, molecular dynamics can also simulate true molecular by external factor, such as temperature, pressure item The equation of motion of one group of particle is established in the influence of part under given external condition, can be obtained respectively after numerical solution is carried out to it Molecule obtains the macroscopic property of system in the method by probability statistics in the motion profile of phase space at each moment.

For this Molecular Simulation Technique from the microcosmic intermolecular interaction of angle research, this is that actual tests can not accomplish , in recent decades with the raising of computer level, Molecular Simulation Technique is also rapidly developed, and has been obtained extensively in every field Application.Molecular dynamics simulation can not only calculate the motion profile and energy variation of molecule in acquisition system, thus to it Macroscopic physical property is analyzed, additionally it is possible to simulate the external environment for being difficult to restore in actual experiment, such as temperature, pressure, no Research precision is improved only, experimental period and cost is also greatly saved.Each example in molecular dynamics simulation system The classical mechanics characteristics of motion is followed, and more meets the true motion state of particle, it can while having correct physical basis The dynamic and macroscopic property of acquisition system, are widely used in various systems i.e. various types of materials, already become a kind of indispensable Research method.

In recent years, although researcher counts the physical property of pitch model using the means of molecular dynamics simulation It calculates and simulates, but evaluation index of pitch such as needle penetration, ductility, softening point etc., it is not possible to directly be calculated by analogue data at present It obtains, existing result of study is also difficult to the pavement performance opening relationships with asphalt material.

Therefore, the present invention carries out molecular dynamics simulation to SBS modified pitch model using molecular dynamics simulation software, By being further improved molecular dynamics simulation algorithm, establish analog result and needle penetration, softening point and ductility test result it Between relationship, to predict the needle penetration of SBS modified pitch, softening point and ductility.

Summary of the invention

(1) technical problem

The object of the present invention is to provide a kind of prediction technique of road modified asphalt material pavement performance, this method is mainly led to It crosses molecular dynamics simulation softward and calculates the physical property of SBS modified pitch, and establish the pass of analog result and test result System, predicts the performance of SBS modified pitch, so that solving can not directly simulate when with molecular dynamics simulation means at present SBS modified pitch needle penetration, ductility and softening point are predicted, is not established between analog result and SBS performance of modified bitumen The problem of relationship.

(2) technical solution

In view of currently without establishing between SBS modified pitch molecular dynamics simulation result and macro property test result The problem of relationship, the present invention mainly by the means of molecular dynamics simulation, provide a kind of prediction side of performance of modified bitumen Method improves the performance of SBS Modified Bitumen Pavement so as to directly obtain the performance of modified pitch by software.The technology of the present invention side Case is as follows: first by density, needle penetration, softening point and the ductility of experiment detection SBS modified pitch, and analytic density enters with needle The correlation of degree, softening point.Using Materials Studio software, it is total to construct single pitch system cell model, SBS block Polymers molecular structure model carries out the geometry optimization of model structure, after the reasonability for verifying two models, sets up the modified drip of SBS Green co-mixing system model, and calculating simulation goes out the density curve of SBS modified pitch co-mixing system model.Then by Materials The SBS modified pitch molecular model of Studio building imports Lammps software, carries out to SBS modified pitch co-mixing system model flat Weighing apparatus, simulates the stretch behavior of modified pitch, tensile elongation when determining that model is broken.It is tied by comparing analog result and experiment Fruit optimizes the algorithm of molecular dynamics simulation, establishes the relationship between measured result and analog result, finally predicts SBS and changes Property pitch needle penetration, softening point and ductility, and pass through needle penetration, softening point and ductility experimental judgment experiment value and the analogue value Consistency.

(3) beneficial effect

Pitch has relatively broad application in fields such as China's road, building, municipal works, and in order to guarantee pitch material Material preferably serves all kinds of engineering constructions, and the three norms of pitch, which check, always to be paid attention to by industry.Pitch three norms are to draw The important technology index for dividing sticky asphalt, to the high-temperature stability of bituminous pavement, low-temperature cracking-resistance, anti-fatigue ability, water Stability and durability have an impact.With largely coming into operation for modified pitch, just results in three norms and change in accurate characterization Property pitch quality and service performance when there is problems, this will study the pitch of modified pitch, production and using all Generate large effect.The simulation of molecular dynamics software has obtained widely answering with forecast function in road asphalt field With, but be mostly the simulation to physical property, the relationship of analog result Yu pitch service performance, therefore, this hair are not established It is bright to propose a kind of means of molecular simulation, by the simulation and forecast of molecular dynamics software, accurately, quickly and intuitively predict The three norms of SBS modified pitch, so as to effectively instruct the production practices of SBS modified pitch, while to improving SBS The using effect of modified pitch builds excellent pavement engineering and is of great significance.

Specific embodiment

The present invention provides a kind of prediction technique of performance of modified bitumen based on molecular dynamics simulation, specific implementation steps It is rapid as follows:

(1) density, softening point, needle penetration and the ductility of SBS modified pitch, the density point of analysis SBS modified pitch are tested Not with the correlation of softening point and needle penetration, SBS modified pitch density and needle penetration, the relational expression of density and softening point are obtained；

(2) by utilizing Sketch the and Build module of Materials Studio software, matrix pitch list is constructed respectively A pitch system cell model, SBS block copolymer molecular structure model, it is excellent based on the minimum progress geometry of model energy Change, verifies the reasonability of two models；

(3) the Amorphous cell module for utilizing Materials Studio software, sets up SBS modified pitch mixture It is model, selects suitable analog parameter, relaxation is carried out to the co-mixing system model, whole system is made to be in a relative equilibrium State, then simulation under isothermal and isobaric (NPT) assemblage is carried out to SBS modified pitch, obtains the density value of co-mixing system；

(4) the SBS modified pitch co-mixing system model for constructing Materials Studio imports Lammps software, right SBS modified pitch co-mixing system model is balanced, and reduces co-mixing system energy, modified to SBS under identical strain rate to drip Green co-mixing system model carries out stretching simulation, tensile elongation when determining that SBS modified pitch co-mixing system model is broken；

(5) SBS modified pitch co-mixing system density value and step (1) middle SBS modified pitch surveyed in analytical procedure (3) In correlation between density, then analytical procedure (4) between tensile elongation and the middle SBS modified pitch ductility surveyed of step (1) Correlation, advanced optimize molecular dynamics simulation algorithm, be respectively increased density value, tensile elongation that numerical simulation obtains with Correlation between the density of actual measurement, ductility, directly by the softening point of molecular dynamics numerical Simulation Prediction SBS modified pitch, prolong Degree and needle penetration；

(6) asphalt softening point measuring method (ring and ball method) (GBT4507-2014), effecting determination of asphalt ductility method (GBT4508- are used 2010), Asphalt Penetration measuring method (GBT4509-2010) measures SBS modified pitch softening point, ductility and needle penetration respectively, with The consistency for verifying molecular dynamics numerical simulation result and measured result, determines SBS modified pitch co-mixing system model and calculation Method.

Claims (1)

1. a kind of prediction technique of the performance of modified bitumen based on molecular dynamics simulation, it is characterised in that the specific step of this method It is rapid as follows:

(1) test SBS modified pitch density, softening point, needle penetration and ductility, analyze SBS modified pitch density respectively with The correlation of softening point and needle penetration obtains SBS modified pitch density and needle penetration, the relational expression of density and softening point；

(2) by utilizing Sketch the and Build module of Materials Studio software, matrix pitch is constructed respectively and is individually dripped Green system cell model, SBS block copolymer molecular structure model are based on the minimum carry out Geometrical optimization of model energy, test Demonstrate,prove the reasonability of two models；

(3) the Amorphous cell module for utilizing Materials Studio software, sets up SBS modified pitch co-mixing system mould Type selects suitable analog parameter, carries out relaxation to the co-mixing system model, whole system is made to be in the shape of a relative equilibrium State, then the simulation under isothermal and isobaric (NPT) assemblage is carried out to SBS modified pitch, obtain the density value of co-mixing system；

(4) the SBS modified pitch co-mixing system model for constructing Materials Studio imports Lammps software, changes to SBS Property pitch co-mixing system model be balanced, reduce co-mixing system energy, under identical strain rate to SBS modified pitch be blended System model carries out stretching simulation, tensile elongation when determining that SBS modified pitch co-mixing system model is broken；

(5) SBS modified pitch co-mixing system density value and step (1) middle SBS modified pitch density surveyed in analytical procedure (3) Between correlation, then the phase between the SBS modified pitch ductility surveyed in tensile elongation and step (1) in analytical procedure (4) Guan Xing advanced optimizes molecular dynamics simulation algorithm, and density value, tensile elongation and actual measurement that numerical simulation obtains is respectively increased Density, correlation between ductility, directly by the softening point of molecular dynamics numerical Simulation Prediction SBS modified pitch, ductility and Needle penetration；

(6) asphalt softening point measuring method (ring and ball method) (GBT4507-2014), effecting determination of asphalt ductility method (GBT4508- are used 2010), Asphalt Penetration measuring method (GBT4509-2010) measures SBS modified pitch softening point, ductility and needle penetration respectively, with The consistency for verifying molecular dynamics numerical simulation result and measured result, determines SBS modified pitch co-mixing system model and calculation Method.