Method for rapid evaluation of salt corrosion resistance of asphalt-aggregate interface

Abstract

This invention provides a rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface, comprising: placing each specimen in a salt solution of different concentrations for different durations of erosion; obtaining the fracture energy of the asphalt-aggregate interface of each specimen; fitting and calculating the parameters of the interface strength salt corrosion damage evolution model; substituting the obtained parameters into the interface strength salt corrosion damage evolution model to obtain the asphalt-aggregate interface strength salt corrosion damage evolution model for the tested asphalt and aggregate; and calculating the interface fracture energy of the tested asphalt and aggregate under the design salt concentration and design erosion duration using the model. This method can obtain the fracture energy of various salt solutions eroded for different durations using the model, and can quickly obtain the results of long-term low-concentration erosion through short-term high-concentration erosion, improving testing efficiency and achieving accurate and systematic quantitative characterization of the corrosion resistance of the asphalt-aggregate interface under different salt concentration environments.

Description

Technical Field

[0001] This invention relates to the field of road engineering testing and evaluation technology, specifically to a rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface. Background Technology

[0002] Asphalt mixtures, as a primary material in pavement engineering, directly impact road service life and performance due to their durability. In practical applications, asphalt mixtures are constantly affected by environmental factors, with performance degradation becoming increasingly prominent, particularly in salt-erosion environments. For example, sulfates and chlorides in saline soils penetrate the pavement structure through capillary action; chloride-based de-icing agents used in winter de-icing in cold regions form corrosive solutions; and coastal areas experience pervasive chloride ions and salt spray. Asphalt mixtures are multiphase composite materials, and their performance largely depends on the integrity of the bond between the asphalt and aggregate interfaces. In these salt-erosion environments, the asphalt-aggregate interface, as the weakest link in the material, faces more complex damage mechanisms than conventional water damage. The presence of salt significantly exacerbates interfacial damage, leading to a sharp decline in the interfacial bond performance between asphalt and aggregates, causing early-stage defects such as pavement spalling and potholes, severely restricting road durability and service life, and resulting in significant maintenance costs and safety risks. Therefore, effectively evaluating the salt corrosion resistance of the asphalt-aggregate interface is a crucial aspect of material selection and design, and is of great significance for constructing long-life pavements.

[0003] Currently, traditional methods for evaluating the water stability of asphalt mixtures (such as the immersion Marshall test and freeze-thaw splitting test) are mainly designed for freshwater environments and have significant limitations in assessing the performance of the asphalt-aggregate interface under salt corrosion conditions. On the one hand, these methods struggle to realistically simulate the complex conditions of multiple salt concentrations and coupled wet-dry / freeze-thaw cycles in actual salt corrosion environments. On the other hand, their evaluation indices, based on overall mechanical properties, are insensitive to localized salt corrosion damage in the interfacial region, making it difficult to accurately capture the degradation process of interfacial bonding performance. Although existing studies have attempted to use pull-out tests to study the salt corrosion resistance of the asphalt-aggregate interface, these studies are mostly limited to specific salt solution concentrations and fixed immersion times, primarily focusing on tests under low salt solution concentrations and long immersion conditions. The conclusions obtained have limited applicability, and a systematic performance evaluation system applicable to a wide concentration range and long immersion conditions has not yet been established.

[0004] To address the aforementioned issues, this application proposes a method for testing and evaluating the salt corrosion resistance of the asphalt-aggregate interface, applicable to a wide range of salt solution concentrations and extensive immersion times. The aim is to achieve a systematic characterization and quantitative assessment of interface performance degradation under different salt erosion intensities and exposure times, providing technical support for the design and durability improvement of asphalt pavement materials in saline environments. Summary of the Invention

[0005] To overcome the shortcomings of the above-mentioned technologies, the purpose of this invention is to provide a rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface, which addresses the limitations of current interface studies based on pull-out tests. These studies only address specific and limited salt solution concentrations and immersion times, and cannot systematically evaluate the evolution of interface performance under a wide range of salt erosion intensities and durations. This invention proposes an evolution model for salt corrosion damage of the asphalt-aggregate interface strength applicable to a wide range of salt solution concentrations and extensive immersion times, as well as a testing and evaluation method for the salt corrosion resistance of the asphalt-aggregate interface.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for constructing a salt corrosion damage evolution model of the asphalt-aggregate interface strength is characterized by the following steps: 1) Obtain the asphalt and aggregate to be tested, and prepare multiple test specimens; 2) Set multiple different salt solution concentrations and erosion durations to form a salt solution concentration gradient and an erosion duration gradient, and place each specimen in a salt solution of different concentrations for different durations of erosion; 3) Pull-out tests were performed on the eroded specimens to obtain the fracture energy of the asphalt-aggregate interface of each specimen; 4) The parameters η and b of the interface strength salt corrosion damage evolution model were calculated by performing nonlinear regression fitting on the salt solution concentration, erosion time, and fracture energy data corresponding to each specimen using the interface strength salt corrosion damage evolution model; wherein, the interface strength salt corrosion damage evolution model is as follows:

[0007] In the formula, G f The fracture energy of the specimen is J / m. 2 G f，0 The fracture energy of the uncorroded, dry specimen, in J / m 2 η represents the interface damage sensitivity; b represents the concentration effect coupling coefficient; C represents the salt solution concentration of the eroded specimen, %; t represents the erosion time of the specimen by the salt solution, d; 5) Substitute the obtained parameters η and b into the interface strength salt corrosion damage evolution model to obtain the asphalt-aggregate interface strength salt corrosion damage evolution model for the asphalt and aggregate to be tested.

[0008] As a preferred embodiment, the asphalt includes any one of the following: base asphalt, SBS modified asphalt, rubber powder modified asphalt, high viscosity and high elasticity asphalt, emulsified asphalt, and high modulus asphalt; the aggregate includes any one of the following: basalt, limestone, diabase, and steel slag.

[0009] As a preferred embodiment, the specimen in step 1) is a sandwich specimen; step 1) includes: Cut the aggregate into square blocks of a specified size; The block and asphalt are heated; the usable quality of the asphalt is calculated based on the thickness of the asphalt film using the following formula:

[0010] In the formula, m is the mass of asphalt, in g; ρ is the density of asphalt, in g / mm³. 3 ; s represents the contact area of ​​the asphalt film, in mm 2 h represents the thickness of the asphalt film, in mm. A piece of aggregate is placed on the lower side of the fixture as a base, and asphalt is evenly coated onto the contact surface of the aggregate. Then, another piece of aggregate is placed on the upper side of the fixture, and the position is adjusted so that the upper and lower sides of the fixture are in contact, thereby placing the other piece of aggregate on the asphalt to obtain a sandwich specimen; the thickness of the asphalt film is controlled to be 10~40μm. The sandwich specimens were left to stand in a constant temperature environment of 25±2℃ for more than 24 hours to ensure that the asphalt and aggregates were fully bonded.

[0011] As a preferred embodiment, the salt solution is a sulfate solution or a chloride solution; the concentration of the salt solution is set to one or more of the following concentrations: 0%, 2.5%, 5%, 10%; the erosion time is set to one or more of the following durations: 0 days, 3 days, 6 days, 9 days, 12 days, 15 days, 18 days, 21 days.

[0012] Furthermore, the sulfate is sodium sulfate; the chloride is sodium chloride.

[0013] Furthermore, the erosion process is set with at least five sets of erosion conditions to obtain at least five sets of data for fitting; each set of data includes salt solution concentration, erosion duration and its corresponding fracture energy data.

[0014] Furthermore, the erosion process is set with six sets of erosion conditions, and six sets of data are obtained for fitting; among them, the salt solution concentration gradient is set to 2.5%, 5%, and 10%, and the erosion duration gradient is set to 3 days and 6 days.

[0015] As a preferred embodiment, the pull-out test is performed using an asphalt viscosity-toughness tester to obtain the tensile-deformation data during the test process, and the fracture energy is obtained by calculating the area under the tensile-deformation curve.

[0016] Furthermore, the method for obtaining the fracture energy includes: plotting a deformation-tensile force curve with deformation as the abscissa and tensile force as the ordinate in the tensile-deformation data; wherein the area enclosed by the deformation-tensile force curve and the ordinate and abscissa is the fracture energy, which can represent the ability of the asphalt-aggregate interface to resist cracking; the formula for calculating the fracture energy is as follows:

[0017] In the formula: E Fra F(x) represents the actual fracture energy obtained from the pull-out test; F(x) is the pull-out stress as a function of deformation.

[0018] As a preferred embodiment, the error formula for the interface strength salt corrosion damage evolution model is as follows: ; In the formula, N represents the number of data points; This represents the measured value of the i-th fracture energy; This represents the fitted value of the i-th fracture energy.

[0019] This invention also provides a rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface. Its unique feature lies in the calculation of the interfacial fracture energy of the asphalt and aggregate under the design salt concentration and design erosion duration using the asphalt-aggregate interface strength salt corrosion damage evolution model obtained through the aforementioned construction method. This evaluation method only requires eroding the specimen with a high-concentration salt solution for a short period to obtain the corresponding data for simulation, thereby obtaining the corresponding asphalt-aggregate interface strength salt corrosion damage evolution model. Subsequently, the fracture energy of various salt concentrations under different erosion times can be calculated using this model. This is particularly useful for situations where existing technologies often require obtaining the fracture energy of asphalt-aggregate under long-term erosion in low-concentration salt solutions. This invention can obtain the asphalt-aggregate interface strength salt corrosion damage evolution model after a short-term high-concentration erosion, thereby calculating the fracture energy under long-term low-concentration erosion, shortening the testing time, improving testing efficiency, and achieving rapid evaluation of the corrosion resistance of the asphalt-aggregate interface.

[0020] As a preferred embodiment, the rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface includes the following steps: Obtain the asphalt and aggregate to be tested, and construct the asphalt-aggregate interface strength salt corrosion damage evolution model for the asphalt and aggregate to be tested using the above construction method. Obtain the design concentration and design erosion duration of the asphalt and aggregate to be tested; Based on the aforementioned salt corrosion damage evolution model of the asphalt-aggregate interface strength, the interfacial fracture energy of the asphalt and aggregate to be tested is calculated using the design concentration and design erosion duration.

[0021] As a preferred embodiment, the asphalt and aggregate to be tested include multiple asphalt-aggregate combinations; the rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface further includes: The salt corrosion damage evolution model of the asphalt-aggregate interface strength corresponding to each asphalt-aggregate combination was obtained, and the fracture energy of each asphalt-aggregate combination under the design concentration and design erosion time was calculated by the asphalt-aggregate interface strength salt corrosion damage evolution model. The fracture energy of multiple asphalt-aggregate combinations was compared, and the higher the fracture energy, the better the salt corrosion resistance.

[0022] This invention also provides a method for testing the salt corrosion resistance life of asphalt-aggregate, which is characterized by including the following steps: The above method is used to construct the salt corrosion damage evolution model of the asphalt-aggregate interface strength for the asphalt and aggregate to be tested. The salt concentration and minimum allowable fracture energy of the application environment of the asphalt and aggregate to be tested are determined. The salt corrosion damage evolution model of the asphalt-aggregate interface strength is used to calculate the salt corrosion resistance service life of the asphalt and aggregate under the salt concentration environment. The minimum allowable fracture energy is the minimum allowable fracture energy threshold predetermined by the engineering design requirements of the asphalt and aggregate in actual engineering design.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface. By constructing a salt corrosion damage evolution model of the asphalt-aggregate interface strength, the fracture energy of different concentrations of salt solution erosion for different durations can be obtained through the model. The results of long-term low-concentration erosion can be quickly obtained through short-term high-concentration erosion, which shortens the test time and effectively improves the test efficiency. It realizes accurate and systematic quantitative characterization of the corrosion resistance of the asphalt-aggregate interface under different salt concentrations.

[0024] This invention provides key technical basis and scientific evaluation methods for the material selection, mix design, durability and service life assessment of asphalt pavement in salt erosion environment, thereby guiding the construction of long-life pavement, improving road service performance and reducing later maintenance costs. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the method for constructing the salt corrosion damage evolution model of the asphalt-aggregate interface strength in this invention. Figure 2 This is a schematic diagram of the deformation-tensile force curve in the pull-out test results; Figure 3 The figure shows the fitting curve of the erosion damage model of sodium sulfate solution on the interface of SBS modified asphalt-steel slag aggregate. Detailed Implementation

[0026] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] The underlying concept of this invention is as follows: I. Establishment of the Differential Equation for the Sulfate Erosion Damage Model The erosion of the asphalt-aggregate interface by sulfate solution is essentially a diffusion process from liquid (containing solute) to the solid interface, including the study of the spatiotemporal distribution of solute concentration in the solid and the influence of solute diffusion on the solid interface properties.

[0028] Fick's second law is the fundamental equation describing the change in concentration over time during diffusion. Most models of ion diffusion within concrete are based on Fick's second law, and these models are among the most widely used and extensively studied. This invention will establish a sulfate erosion damage evolution model of the asphalt-aggregate interface performance under certain assumptions, based on Fick's second law. The model formula is as follows: (1) In the formula: C represents the salt solution concentration (%), t represents the salt solution erosion time (d), and D represents the effective diffusion coefficient of ions (m). 2 / s; x represents the normal distance from the exposed surface.

[0029] II. Establishment of the General Form of the Sulfate Erosion Damage Model (1) Basic assumptions a. Diffusion process: The diffusion process of the solute obeys Fick's second law for one-dimensional diffusion; b. Boundary conditions: Constant concentration at the interface: C(0,t)=C0; No solute initially: C(x,0)=0; No diffusion at infinity: C(∞,t)=0; c. Damage mechanism: Strength loss is proportional to the cumulative amount of ions at the interface.

[0030] (2) Solving the diffusion equation Considering the boundary conditions set in step (1), solving the model equations shown in Equation 1 yields the particular solution: (2); Where the error function erf is: (3); Where u is the integral variable, which is dimensionless.

[0031] (3) Interface Influence Analysis The gradient concentration at the interface (x=0) is: (4); The total permeability Q(t) per unit area is: (5) Assuming that the interfacial strength loss is proportional to the total ion permeation, then: (6) In the formula: S(t) represents the residual strength of the interface, S0 represents the initial strength of the interface, and k represents the interface damage sensitivity coefficient.

[0032] (4) Simplified model Considering that the deteriorating effect of sulfate solution on the asphalt-aggregate interface is caused not only by the solute sulfate but also by water, the concentration-related terms in the formula are modified. Meanwhile, the interfacial strength is represented by the fracture energy G. f This indicates that an interfacial strength salt corrosion damage evolution model applicable to this study object is obtained, namely: (7) In the formula, η represents the interface damage sensitivity; b represents the concentration effect coupling coefficient; G f，0 The fracture energy of the uncorroded dry specimen is obtained by pull-out testing of the uncorroded dry specimen (i.e., specimen with an corrosion duration of 0 days).

[0033] Further analysis of Equation 7 revealed an equivalence relationship between sulfate concentration and erosion time on interfacial damage. Specifically, damage caused by erosion with a lower concentration of sulfate solution over a longer period is equivalent to damage caused by erosion with a higher concentration of sulfate solution over a shorter period. This equivalence relationship can be expressed as: (8) and: (9) In the formula, The concentration-erosion time shift factor.

[0034] Therefore, when the selected reference concentration is The damage model expression for a time t after erosion by a sodium sulfate solution of concentration C is: (10) and: (11) In the formula, The solution concentration is The equivalent erosion duration at that time.

[0035] III. Solving the parameters of the sulfate solution erosion damage model: This was done through specific experiments.

[0036] The above model-building approach and parameter-solving process based on sulfate solutions are also applicable to chloride solutions.

[0037] Based on the above ideas, the method of this invention is obtained: like Figure 1 As shown, the method for constructing the salt corrosion damage evolution model of the asphalt-aggregate interface strength and the method for rapidly evaluating the salt corrosion resistance of the asphalt-aggregate interface in this invention include the following steps: 1) Specimen preparation To effectively simulate the actual bonding of asphalt mixtures, this invention employs an aggregate-asphalt sandwich specimen to analyze the interfacial properties between the asphalt and aggregate. The asphalt can be selected from common road asphalts such as base asphalt, SBS modified asphalt, rubber-modified asphalt, high-viscosity and high-elasticity asphalt, emulsified asphalt, and high-modulus asphalt; the aggregate can be selected from common road aggregates such as basalt, limestone, diabase, and steel slag.

[0038] The specific preparation process for sandwich specimens is as follows: (1) Cut the aggregate into square blocks with a length of 20mm, a height of 20mm, and a thickness of 20mm, with an asphalt contact area of ​​20mm×20mm. To ensure that the surface roughness is similar, grind and polish the blocks, then clean them with ultrasonic equipment and dry them for later use.

[0039] (2) During specimen preparation, the thickness of the asphalt film needs to be controlled. The asphalt film thickness ranges from 10 to 40 μm. The formulas for calculating the required asphalt mass for specimens with different film thicknesses are as follows: (12) In the formula: m is the mass of the asphalt film, g; ρ is the density of asphalt, g / mm³. 3 ; s represents the contact area of ​​the asphalt film, in mm 2 h represents the thickness of the asphalt film, in mm.

[0040] (3) After heating the asphalt and aggregate specimens, place one piece of aggregate under the fixture as a base, weigh the asphalt calculated by formula 12 and evenly coat it on the aggregate contact surface, then place another piece of aggregate on the upper side of the fixture, adjust the position so that the upper and lower sides of the fixture are in contact and accurately control the thickness of the asphalt film.

[0041] (4) Place the prepared sandwich specimen in a constant temperature environment of 25℃ for more than 24 hours to ensure that the asphalt and aggregate are fully bonded.

[0042] 2) Sulfate corrosion test To simulate a sulfate environment, multiple different sulfate solution concentrations and curing (erosion) durations were set to create a gradient between sulfate solution concentration and erosion duration. Sulfate solutions of varying concentrations were prepared. At least five sets of erosion conditions were established to obtain at least five sets of data for fitting, ensuring the accuracy of the fit.

[0043] Then, multiple sandwich-type specimens prepared in step one were placed in sulfate solutions of different concentrations for different curing times to investigate the effects of erosion time and sulfate solution concentration on the asphalt-aggregate interface. It is important to note that to ensure the salt solution concentration is not affected by volatilization, it should be placed in a sealed container. The sulfate solution concentration can be set to one or more of the following concentrations: 0%, 2.5%, 5%, 10%; the erosion time can be set to one or more of the following durations: 0 days, 3 days, 6 days, 9 days, 12 days, 15 days, 18 days, 21 days.

[0044] 3) Pull-out test Pull-out tests were conducted on each specimen after sulfate solution erosion using an asphalt visco-toughness tester, and the tensile force-deformation data during the test loading process were recorded. A deformation-tensile force curve was plotted with deformation on the x-axis and tensile force on the y-axis, as shown below. Figure 2 The figure shows the deformation-tensile force curve of the asphalt-steel slag interface before erosion. The area enclosed by the deformation-tensile force curve and the vertical and horizontal axes represents the fracture energy at which the asphalt-aggregate interface fails, indicating its resistance to cracking. The calculation formula is shown in Equation 13. (13) In the formula: E Fra F(x) represents the actual fracture energy obtained from the pull-out test; F(x) is the pull-out stress as a function of deformation.

[0045] 4) Solving for model parameters Based on the fracture energy data of the asphalt-aggregate interface under different concentrations of solution and different erosion durations obtained in steps 1) to 3), at least five sets of data were used to perform nonlinear regression fitting using the model shown in Equation 7. After correcting the fitted model through the error equation, the model parameters η and b were obtained; the fitting error equation is shown in Equation 14. The evaluation index is the goodness of fit R. 2 To determine.

[0046] (14) In the formula, N represents the number of data points; This represents the measured value of the i-th fracture energy; This represents the fitted value of the i-th fracture energy.

[0047] 5) Substitute the obtained parameters η and b into the above interface strength salt corrosion damage evolution model to obtain the asphalt-aggregate interface strength salt corrosion damage evolution model for the asphalt and aggregate to be tested.

[0048] 6) Calculate and obtain the interfacial fracture energy of the asphalt and aggregate under the design salt concentration and design erosion duration using the asphalt-aggregate interface strength salt corrosion damage evolution model obtained in step 5). That is, substitute the design salt concentration and design erosion duration into the above asphalt-aggregate interface strength salt corrosion damage evolution model to obtain the corresponding fracture energy.

[0049] 7) Set up multiple asphalt-aggregate combinations and repeat steps 1)-6) respectively to obtain the salt corrosion damage evolution model of the asphalt-aggregate interface strength corresponding to each asphalt-aggregate combination, and calculate the fracture energy of each asphalt-aggregate combination under the design concentration and design erosion time; compare the fracture energy of multiple asphalt-aggregate combinations, and the higher the fracture energy, the better the salt corrosion resistance.

[0050] The asphalt-aggregate interface strength salt corrosion damage evolution model of the present invention can also be used to predict the salt corrosion resistance life of asphalt-aggregate, including the following steps: Construct a salt corrosion damage evolution model for the asphalt-aggregate interface strength of the asphalt and aggregate to be tested; The salt concentration and minimum allowable fracture energy of the application environment of the asphalt and aggregate to be tested are determined. The salt concentration and minimum allowable fracture energy are then substituted into the salt corrosion damage evolution model of the asphalt-aggregate interface strength to calculate the service life of the asphalt and aggregate under the salt concentration environment. The minimum allowable fracture energy is the minimum allowable fracture energy threshold predetermined by the engineering design requirements of the asphalt and aggregate in the actual engineering design, that is, the fracture energy set when the service life is reached, which is determined by the actual project or relevant specifications.

[0051] The invention will be illustrated below through specific implementation examples.

[0052] In this specific implementation case: the asphalt to be tested was SBS modified asphalt and No. 70 base asphalt, and the aggregates were steel slag aggregate and basalt aggregate; the asphalt film thickness was 20 μm; sodium sulfate was used as the sulfate, and the mass concentrations of the sodium sulfate solutions were 0%, 2.5%, 5%, and 10%; the erosion periods were set to 0 days, 3 days, 6 days, 9 days, 12 days, 15 days, 18 days, and 21 days. The model parameter fitting results are shown in Table 1, and the model fitting curves are shown in Table 2. Figure 3 As shown.

[0053] From Table 1 and Figure 3It can be seen that the goodness of fit of all types of asphalt-aggregate interface strength damage models is greater than 0.9, and the model curves and experimental data have a good degree of overlap, indicating that the sulfate solution erosion damage model proposed in this invention has high accuracy.

[0054] Table 1: Parameters of the sulfate erosion damage model (C R :0%)

[0055] Analyze the parameter G in Table 1 f,0 It can be seen that when the asphalt type is the same, G f,0_玄武岩 <G f,0_钢渣 This indicates that, under dry conditions, the interfacial properties of basalt-asphalt are weaker than those of steel slag-asphalt; when the aggregate type is the same, G f,0_SBS改性沥青 >G f,0_70#基质沥青 This indicates that, under dry conditions, the interfacial properties of 70# base asphalt-aggregate are weaker than those of SBS modified asphalt-aggregate. These results demonstrate that the model parameter G proposed in this invention... f,0 It can identify the influence of aggregate type and asphalt type on the properties of the asphalt-aggregate interface under dry conditions.

[0056] Analysis of parameter η in Table 1 shows that when the asphalt type is the same, η _玄武岩 >η _钢渣 This indicates that, compared to the performance of the steel slag-asphalt interface, the interfacial performance of the basalt-asphalt interface is more significantly affected by changes in erosion time and solution concentration; when the aggregate type is the same, η _SBS改性沥青 <η _70#基质沥青 This indicates that the interfacial properties of the SBS-modified asphalt-aggregate interface are less affected by changes in erosion time and solution concentration. These results demonstrate that the model parameter η proposed in this invention can identify the influence of aggregate type and asphalt type on the sensitivity of the asphalt-aggregate interface properties to changes in solution concentration and erosion time.

[0057] Analysis of parameter b in Table 1 shows that all b values ​​are positive, indicating that an increase in solution concentration is equivalent to an increase in erosion time. This suggests that the establishment of this model can provide a theoretical basis for evaluating the influence of sodium sulfate solution on the properties of the asphalt-aggregate interface within a wide erosion time threshold. In other words, in order to evaluate the long-term erosion damage effect of low-concentration sodium sulfate solution on the asphalt-aggregate interface, it can be measured by a test with a high-concentration solution and a shorter erosion time, effectively shortening the test time.

[0058] The above results show that the salt corrosion damage evolution model of the asphalt-aggregate interface strength constructed in this invention can accurately and systematically quantify the corrosion resistance of the asphalt-aggregate interface. It can quickly obtain the results of long-term low-concentration erosion through short-term high-concentration erosion, shorten the test time, and improve the test efficiency.

[0059] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for constructing a salt corrosion damage evolution model of asphalt-aggregate interface strength, characterized in that, Includes the following steps: 1) Obtain the asphalt and aggregate to be tested, and prepare multiple test specimens; 2) Set up salt solution concentration gradients and erosion time gradients, and place each specimen in salt solutions of different concentrations for different erosion times; 3) Perform pull-out tests on the eroded specimens to obtain the fracture energy of the asphalt-aggregate interface of each specimen; 4) The salt solution concentration, erosion time, and fracture energy data corresponding to each specimen were fitted using the interface strength salt corrosion damage evolution model to calculate the parameters η and b of the interface strength salt corrosion damage evolution model; wherein, the interface strength salt corrosion damage evolution model is as follows: ； In the formula, G f is the fracture energy of the uneroded dry test piece, J / m 2 ; G f,0 is the fracture energy of the uneroded dry test piece, J / m 2 ; η represents the interface damage sensitivity; b represents the concentration effect coupling coefficient; C represents the concentration of the salt solution eroding the test piece, %; and t represents the eroding time of the salt solution on the test piece, d. 5) Substitute the obtained parameters η and b into the interface strength salt corrosion damage evolution model to obtain the asphalt-aggregate interface strength salt corrosion damage evolution model for the asphalt and aggregate to be tested.

2. The construction method according to claim 1, characterized in that, The asphalt includes any one of the following: base asphalt, SBS modified asphalt, rubber powder modified asphalt, high viscosity and high elasticity asphalt, emulsified asphalt, and high modulus asphalt; the aggregate includes any one of the following: basalt, limestone, diabase, and steel slag.

3. The construction method according to claim 1, characterized in that, The salt solution is a sulfate solution or a chloride solution.

4. The construction method according to claim 1, characterized in that, The erosion process sets at least five erosion conditions to obtain at least five sets of data for fitting.

5. The construction method according to claim 1, characterized in that, In the pull-out test, tensile-deformation data are acquired during the test, and the fracture energy is obtained by calculating the area under the tensile-deformation curve.

6. The construction method according to any one of claims 1-5, characterized in that, The error formula for the interface strength salt corrosion damage evolution model is as follows: ； In the formula, N represents the number of data points; This represents the measured value of the i-th fracture energy; This represents the fitted value of the i-th fracture energy.

7. A rapid evaluation method for the salt corrosion resistance of asphalt-aggregate interface, characterized in that, The interfacial fracture energy of the asphalt and aggregate under test is calculated using the salt corrosion damage evolution model of the asphalt-aggregate interface strength obtained by the construction method described in any one of claims 1-6, under the design salt concentration and design erosion duration.

8. The rapid evaluation method for salt corrosion resistance of asphalt-aggregate interface according to claim 7, characterized in that, Includes the following steps: Obtain the asphalt and aggregate to be tested, and construct the asphalt-aggregate interface strength salt corrosion damage evolution model for the asphalt and aggregate to be tested using the construction method described in any one of claims 1-6. Obtain the design concentration and design erosion duration of the asphalt and aggregate to be tested; Based on the aforementioned salt corrosion damage evolution model of the asphalt-aggregate interface strength, the interfacial fracture energy of the asphalt and aggregate to be tested is calculated using the design concentration and design erosion duration.

9. The rapid evaluation method for salt corrosion resistance of asphalt-aggregate interface according to claim 8, characterized in that, The asphalt and aggregate to be tested include multiple asphalt-aggregate combinations; the rapid evaluation method for the salt corrosion resistance of the asphalt-aggregate interface further includes: The salt corrosion damage evolution model of the asphalt-aggregate interface strength corresponding to each asphalt-aggregate combination was obtained, and the fracture energy of each asphalt-aggregate combination under the design concentration and design erosion time was calculated by the asphalt-aggregate interface strength salt corrosion damage evolution model. The fracture energy of multiple asphalt-aggregate combinations was compared, and the higher the fracture energy, the better the salt corrosion resistance.

10. A method for testing the salt corrosion resistance life of asphalt-aggregate, characterized in that, Includes the following steps: A salt corrosion damage evolution model of the asphalt-aggregate interface strength for the asphalt and aggregate to be tested is constructed using the construction method described in any one of claims 1-6. The salt concentration and minimum allowable fracture energy of the application environment of the asphalt and aggregate to be tested are determined. The salt corrosion damage evolution model of the asphalt-aggregate interface strength is used to calculate the salt corrosion resistance service life of the asphalt and aggregate under the salt concentration environment. The minimum allowable fracture energy is the minimum allowable fracture energy threshold predetermined by the engineering design requirements of the asphalt and aggregate in actual engineering design.

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