A method and apparatus for testing the interfacial interaction of a sandwich structure asphalt aggregate using a pull-off test

Abstract

The present application belongs to the technical field of road construction materials, and relates to a method and device for testing the interaction of a sandwich structure asphalt aggregate interface by means of a pull-out test, the method comprising: S1, using a set aggregate type and asphalt type, producing a plurality of sandwich structure standard test pieces; S2, obtaining an interaction standard value and a bonding strength standard value, and constructing a standard database; S3, according to the constructed standard database, taking the bonding strength standard value as the horizontal coordinate and the interaction standard value as the vertical coordinate, constructing a standard model of the interaction and the bonding strength; S4, producing a sandwich structure test piece to be tested, obtaining a bonding strength test value, substituting the bonding strength test value into the standard model of the interaction and the bonding strength, and calculating an actual interaction value. The present application tests the interaction of a sandwich structure asphalt aggregate interface by means of a pull-out test, so that the test of the interaction is simpler, and the performance of the interaction between the asphalt-aggregate interface can be well reflected.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of road construction materials, and relates to a method and device for testing the interaction between the sandwich structure asphalt aggregate interface by using a pull-out test. BACKGROUND

[0002] Asphalt pavement is the main type of high-grade road, but with the increase of service life, the continuous increase of traffic volume, the overload of heavy trucks and the change of environment, diseases will continuously occur in asphalt pavement, affecting the road performance; for example, water damage, rutting, cracking and other diseases will occur in asphalt pavement, which will affect the road performance and driving comfort, and even affect the road safety. Therefore, improving the road performance and service life of asphalt pavement is an urgent problem to be solved in road engineering.

[0003] At present, a large number of studies have been conducted on the diseases of asphalt pavement, and the results show that the damage is closely related to the properties of the asphalt-aggregate interface. The interface behavior of asphalt and aggregate refers to a series of complex reactions between asphalt and aggregate, such as adsorption, diffusion, chemical bonding, etc. Once the asphalt-aggregate interface is damaged, the stability of asphalt mixture is reduced, and the overall performance is weakened. In the formation process of asphalt mortar, asphalt is redistributed on the surface of the filler due to the interaction between the asphalt-filler interface, the stronger the interaction, the more compact the structure between the asphalt-filler interface, and the more excellent the physical and mechanical properties, so as to make the stability of asphalt mixture better; at the same time, from the perspective of interface adhesion, the bonding strength between the asphalt-aggregate interface and the overall stability of the mixture have great relevance, generally, the higher the bonding strength between the asphalt-aggregate interface, the stronger the water stability and anti-rutting performance of the mixture, and at the same time, the overall strength and structure are also better, so as to ensure that the road has a longer service life and better service quality. At present, the interaction is investigated from the action dimension between asphalt and filler, and the interface adhesion (bonding strength) is investigated from the action dimension between asphalt and aggregate. The separate analysis of the two factors ignores the relationship between the interaction and the bonding strength, which cannot well reflect the action performance between the asphalt-aggregate interface; in addition, due to the lack of correlation between the interaction and the bonding strength, the test of the interaction can only be obtained by multiple influencing factors such as the complex modulus of asphalt and the proportion of filler, which leads to the complexity of the test of the interaction. SUMMARY

[0004] In view of the technical problems of separate analysis of the existing interaction and bonding strength and the complicated test process of the interaction, the application provides a method and device for testing the interaction between the sandwich structure asphalt aggregate interface by using a pull-out test.

[0005] The application builds a standard model of interaction and bonding strength by establishing a standard database of sandwich structure asphalt aggregate, tests the interaction of sandwich structure asphalt aggregate interface by pull-out test, so that the test of interaction is simpler, and the correlation between interaction and bonding strength is built, which can well reflect the interaction performance between asphalt-aggregate interface.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is:

[0007] A method for testing the interface interaction of sandwich structure asphalt aggregate by pull-out test, comprising the following steps:

[0008] S1, making standard test pieces

[0009] A plurality of standard test pieces of sandwich structure are made by using the set aggregate type and asphalt type;

[0010] A plurality of DSR samples are made by using the set aggregate type and asphalt type and using a conventional method;

[0011] S2, building a standard database

[0012] The interaction standard value of each DSR sample is obtained by using a conventional test method for the plurality of DSR samples of step S1;

[0013] The interaction standard value of each standard test piece is obtained by using a conventional test method for the plurality of standard test pieces of sandwich structure of step S1;

[0014] The bonding strength standard value of each standard test piece is obtained by using a pull-out test for the plurality of standard test pieces of sandwich structure of step S1;

[0015] The standard database is built by using the obtained interaction standard value and bonding strength standard value;

[0016] S3, building a standard model of interaction and bonding strength

[0017] The standard curve C=b+kσ is obtained by normalizing the standard database with the bonding strength standard value as the abscissa and the interaction standard value as the ordinate, which is the standard model of interaction and bonding strength; wherein C is the interaction, σ is the bonding strength, k is the slope, and b is the intercept;

[0018] S4, interaction test

[0019] The bonding strength test value is obtained by using a pull-out test for the sandwich structure test piece, and then the actual value of the interaction is calculated by substituting the bonding strength test value into the standard curve.

[0020] Further limited, the specific process of the step S1 is:

[0021] S11, aggregate processing

[0022] The aggregate is processed to obtain a cylindrical aggregate stone sheet, and then polished, washed and dried to obtain an aggregate round sheet.

[0023] S12, making a standard test piece

[0024] The asphalt is added between the two aggregate round sheets, and the thickness of the asphalt film is controlled by a dynamic shear rheometer to obtain a sandwich structure standard test piece, which is cured at room temperature for 24 hours.

[0025] Further limited, the size of the aggregate stone sheet is: diameter 25mm, height 5mm.

[0026] Further limited, the process of polishing, washing and drying is:

[0027] The surface of the stone sheet is polished with 1200 mesh sandpaper, then washed with distilled water, and then boiled in boiling water for 10 minutes; finally heated at 100°C for 3 hours.

[0028] Further limited, in the step S12, the specific process of obtaining a sandwich structure standard test piece is:

[0029] The two aggregate round sheets and the asphalt are kept at a constant temperature of 165°C for 40 minutes;

[0030] The two aggregate round sheets are clamped in the fixture, the two aggregate round sheets are arranged opposite to each other, and a gap is left between the two aggregate round sheets, the fixture is connected with the DSR rotor, the asphalt is injected between the two aggregate round sheets, the thickness of the asphalt film is controlled by the DSR, and the sample is scraped with a heated scraper to obtain a sandwich structure standard test piece.

[0031] A test device for implementing the method of testing the interaction of the sandwich structure asphalt aggregate interface by using the pull-out test, the test device comprising:

[0032] Aggregate fixture: for loading and holding aggregate;

[0033] DSR testing machine: for connecting with the aggregate fixture, adding asphalt between the aggregate to form a sandwich structure standard test piece and a sandwich structure test piece to be tested; also used for obtaining the interaction standard value of the sandwich structure standard test piece by using a conventional test method;

[0034] Pull-out test device: for performing a pull-out test on the formed sandwich structure standard test piece and the sandwich structure test piece to be tested by using the aggregate fixture, and obtaining the corresponding bonding strength standard value and bonding strength test value;

[0035] a data storage module for storing the interaction standard value, the bonding strength standard value and the bonding strength test value;

[0036] a data processing module for constructing a standard database and a standard model of the interaction and the bonding strength according to the interaction standard value and the bonding strength standard value, and for calculating the interaction actual value according to the bonding strength test value.

[0037] Further, the aggregate clamp comprises a first aggregate loading platform and a second aggregate loading platform.

[0038] The first aggregate loading platform comprises an upper clamping part and a lower aggregate loading part, and the clamping part and the aggregate loading part are connected to form a stepped structure with a small upper part and a large lower part.

[0039] The lower surface of the aggregate loading part is provided with an aggregate loading groove for placing an aggregate disc, and the clamping part is used for connecting with a DSR testing machine or a pulling test device.

[0040] The second aggregate loading platform has the same structure as the first aggregate loading platform and is distributed in a mirror image.

[0041] Further, the test device further comprises a rotor rod, and the rotor rod comprises a connecting end part, a rotating connecting rod and a rotor base connected in sequence from top to bottom.

[0042] The connecting end part is used for connecting with the rotor of the DSR testing machine, and the rotor base is used for clamping with the clamping part of the first aggregate loading platform.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] 1. The present application establishes a standard database of the sandwich structure asphalt aggregate, and then constructs a standard model of the interaction and the bonding strength, tests the interface interaction of the sandwich structure asphalt aggregate by the pulling test, so that the test of the interaction is simpler, and the correlation between the interaction and the bonding strength is constructed, which can well reflect the interaction performance between the asphalt-aggregate interface.

[0045] 2. The standard model of the interaction and the bonding strength is constructed, so that a functional relationship between the interface adhesion strength and the interaction is established, and compared with the existing rheological method for testing the interaction, the operation process of the pulling test is simple, and the test method is scientific and reasonable.

[0046] 3. The test method provided by the present application tests the interface interaction strength of the sandwich structure asphalt aggregate by the simple pulling test, and provides a reference for quickly evaluating the strength of the interface interaction.

[0047] 4、The present application shows that the constructed standard model is scientific and reasonable by analyzing the correlation and significance of the constructed interaction and bonding strength standard model, and the interaction of the asphalt aggregate interface can be accurately tested by the drawing test. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 A schematic view of the main view of the aggregate clamp structure provided by the present application is shown in the figure.

[0049] Figure 2 A schematic view of the main view of the aggregate clamp structure provided by the present application is shown in the figure. Figure 1

[0050] Figure 3 A schematic view of the rotor rod is shown in the figure.

[0051] Figure 4 A schematic view of the aggregate clamp and rotor connection structure is shown in the figure.

[0052] Among them:

[0053] 100-First aggregate loading platform; 110-Aggregate loading part; 111-Aggregate loading groove; 112-Aggregate fixing hole; 120-Clamping part; 200-Second aggregate loading platform; 300-Rotor rod; 310-Connection end; 320-Rotary connecting rod; 330-Rotor base; 331-Slot; 332-Rotor fixing hole. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application will be further described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0055] The present application provides a method for testing the interaction of sandwich structure asphalt aggregate interface by drawing test, comprising the following steps:

[0056] S1, making standard test piece

[0057] A plurality of standard test pieces of sandwich structure are made by using the set aggregate type and asphalt type.

[0058] The specific process of the step S1 of making standard test piece is:

[0059] S11, aggregate treatment

[0060] The aggregate is treated to obtain a cylindrical aggregate stone sheet, and then polished, washed and dried to obtain an aggregate round sheet.

[0061] ​Preferably, the size of the aggregate stone sheet is: diameter 25mm, height 5mm.

[0062] Preferably, the process of polishing, cleaning and drying treatment is:

[0063] The surface of the stone sheet is polished by using 1200 mesh sandpaper, then washed with distilled water, then boiled in boiling water for 10min, and finally heated at 100℃ for 3h.

[0064] S12, making a standard test piece

[0065] The asphalt is added between the two aggregate round sheets, and the asphalt film thickness is controlled by a dynamic shear rheometer, so as to obtain a sandwich structure standard test piece, and the sandwich structure standard test piece is cured at room temperature for 24h.

[0066] Specifically, in step S12, the specific process of obtaining the sandwich structure standard test piece is:

[0067] The two aggregate round sheets and the asphalt are kept at a constant temperature of 165℃ for 40min.

[0068] The two aggregate round sheets are clamped in the fixture, the two aggregate round sheets are arranged oppositely, and a gap is left between the two aggregate round sheets, the fixture is connected with the DSR rotor, the asphalt is injected between the two aggregate round sheets, the asphalt film thickness is controlled by the DSR, and the sample is scraped by a heated scraper, so as to obtain a sandwich structure standard test piece.

[0069] Preferably, the fixture comprises a first fixture and a second fixture; the first fixture and the second fixture are both stepped structures with small upper part and large lower part; a first groove is formed on the lower surface of the first fixture, and a second groove is formed on the lower surface of the second fixture; the size of the first groove and the size of the second groove are matched with the size of the aggregate round sheet; the first groove and the second groove are used for placing the two aggregate round sheets; the first groove and the second groove are oppositely arranged, and the upper part of the first fixture and the upper part of the second fixture are respectively connected with the DSR rotor.

[0070] Since the existing method for controlling the asphalt film thickness is mainly controlled by experience, it is difficult to ensure the asphalt thickness each time, and it is difficult to control the uniformity when uniformly coating, and the film thickness control cannot be accurately operated to the micron level, resulting in a large error in the interface mechanics test. In the present application, the fixture and the DSR are combined to accurately control the thickness of the asphalt film.

[0071] In this embodiment, a plurality of DSR samples are made by using a set of aggregate types and asphalt types and using a conventional method.

[0072] S2, constructing a standard database

[0073] S21, for the plurality of DSR samples of step S1, the interaction standard value of each DSR sample is obtained by using a conventional test method.

[0074] Specifically, the conventional test method is to obtain the interaction standard value between asphalt and filler by using DSR. Specifically, the interaction standard value is calculated according to the following calculation formula:

[0075]

[0076] Wherein: C is the interaction, and the value of C reflects the strength of the interaction; φ is the volume fraction of the filler; G* is the complex shear modulus of the asphalt mortar (Pa) ; G* is the complex shear modulus of the base asphalt (Pa).

[0077] S22, for the plurality of sandwich structure standard samples of step S1, the bonding strength standard value of each standard sample is obtained by using a pull-out test.

[0078] In the present application, the bonding strength standard value obtained by using the pull-out test is calculated by using the following formula:

[0079]

[0080] Wherein: F is the pull-out force (KN) ; A is the contact area between the asphalt and the aggregate (m 2 ).

[0081] The interaction standard value and the bonding strength standard value obtained above are used to construct a standard database.

[0082] S3, constructing a standard model of interaction and bonding strength

[0083] For the constructed standard database, the bonding strength standard value is used as the abscissa, and the interaction standard value is used as the ordinate, and through normalization processing, a standard curve C=b+kσ is obtained, which is the standard model of interaction and bonding strength: wherein C is the interaction, σ is the bonding strength, k is the slope of the standard curve, and b is the intercept.

[0084] S4, interaction test

[0085] The sandwich structure test sample is taken, the bonding strength test value is obtained by using the pull-out test, and then the bonding strength test value is substituted into the standard curve to calculate the actual value of the interaction.

[0086] Through the above method, firstly, the relationship between the asphalt aggregate interface interaction and the bonding strength of the sandwich structure is constructed, which can not only well reflect the interaction performance between the asphalt-aggregate interface, but also has great reference value for the durability analysis of the asphalt pavement; more importantly, the size of the asphalt aggregate interface interaction of the sandwich structure is tested by the pull-out test, and the test method is simple, accurate and efficient.

[0087] The method provided by the present application is described in detail below with specific examples.

[0088] It should be noted that, unless otherwise specified, the materials used in the following examples are commercially available products commonly used in the art.

[0089] It should be noted that, unless otherwise specified, the operating temperature of the following examples is room temperature.

[0090] Example 1

[0091] The present embodiment provides a method for testing the asphalt aggregate interface interaction of the sandwich structure by pull-out test, comprising the following steps:

[0092] S1, making standard test pieces

[0093] Using the set types of aggregate and asphalt, a plurality of DSR samples are made by conventional methods.

[0094] Using the set types of aggregate and asphalt, a plurality of standard test pieces of sandwich structure are made.

[0095] In this embodiment, the types of aggregate are calcite, albite and quartz. The types of asphalt are 70# base asphalt and 90# base asphalt.

[0096] According to the above design of aggregate type and asphalt type, a total of 6 DSR samples and 6 standard test pieces of sandwich structure are made. They are: 70# base asphalt-calcite, 70# base asphalt-albite, 70# base asphalt-quartz, 90# base asphalt-calcite, 90# base asphalt-albite and 90# base asphalt-quartz.

[0097] In this embodiment, the method for making DSR samples is referred to the Highway Engineering Asphalt and Asphalt Mixture Test Procedures. Specifically, a 25mm rotor and a 1mm thick DSR frequency scanning test are used.

[0098] In this embodiment, in order to make the above-mentioned standard test pieces of sandwich structure, the present embodiment also provides an aggregate clamp and a rotor rod, which are connected with the DSR testing machine through the clamp and the rotor rod. The DSR testing machine is used to strictly control the thickness of the asphalt film, which not only ensures uniformity, but also controls the thickness of the asphalt film to the micron level, with very small test error and high accuracy.

[0099] Referring to Figure 1 and Figure 2 The aggregate clamp comprises a first aggregate loading platform 100 and a second aggregate loading platform 200.

[0100] In this embodiment, the first aggregate loading platform 100 is a stepped columnar structure with a small upper part and a large lower part. Specifically, the first aggregate loading platform 100 comprises a clamping part 120 at the upper part and an aggregate loading part 110 at the lower part, and the clamping part 120 and the aggregate loading part 110 are connected to form an integrated structure. Both the clamping part 120 and the aggregate loading part 110 are cylindrical structures. A counterbore is formed on the upper surface of the clamping part 120 for mounting and fixing with external equipment.

[0101] An aggregate loading groove 111 is formed on the lower surface of the aggregate loading part 110, and an aggregate fixing hole 112 is formed on the side wall of the aggregate loading part 110. The aggregate loading groove 111 is used to place an aggregate disc, and the aggregate disc is fixed by a screw passing through the aggregate fixing hole 112.

[0102] In this embodiment, in order to enhance the stability of the aggregate disc, the aggregate fixing hole 112 is a plurality of holes, and the plurality of aggregate fixing holes 112 are uniformly distributed in a circle in the circumferential direction of the aggregate loading part 110.

[0103] Preferably, the aggregate fixing hole 112 is three, and can also be four or five.

[0104] In this embodiment, the structure of the second aggregate loading platform 200 is mirror image distributed with the structure of the first aggregate loading platform 100.

[0105] Referring to Figure 3 and Figure 4 In this embodiment, the rotor rod 300 comprises a connecting end part 310, a rotating connecting rod 320 and a rotor base 330 connected in sequence from top to bottom, and the rotor base 330 is a cylindrical structure. The connecting end part 310 is used to connect with the rotor of the DSR tester, and an inner recessed clamping groove 331 is arranged on the lower bottom surface of the rotor base 330. The inner diameter of the clamping groove 331 matches the outer diameter of the clamping part 120. When the rotor base 330 is clamped on the clamping part 120, the bottom end of the rotating connecting rod 320 is clamped in the counterbore on the upper surface of the clamping part 120. In order to facilitate the fixation of the rotor rod 300 and the first aggregate loading platform 100, a rotor fixing hole 332 is formed on the side wall of the rotor base 330. When the clamping groove 331 is clamped on the clamping part 120, the screw contacts the outside of the clamping part 120 through the rotor fixing hole 332, so as to clamp the first aggregate loading platform 100.

[0106] In this embodiment, the rotor fixing hole 332 is multiple, and the multiple rotor fixing holes 332 are uniformly distributed in a circle in the circumferential direction of the rotor base 330, so as to lock the clamping part 120 from different directions, and the rotor rod 300 and the first aggregate loading table 100 are fixed more firmly.

[0107] Preferably, the rotor fixing hole 332 is four, and can also be three or five.

[0108] In this embodiment, the six sandwich structure standard test pieces are made by the following method:

[0109] 1.1, aggregate disc

[0110] (1) Make stone column: aggregate is processed into 100mmx100mmx20mm size, and then a drill core machine is used to obtain an aggregate stone column (cylindrical) with a diameter of 25mm.

[0111] (2) Make stone disc: use a cutting machine to cut the prepared aggregate stone column to obtain an aggregate stone disc (cylindrical) with a height of 5mm.

[0112] (3) Aggregate surface treatment: In order to reduce the influence of aggregate surface roughness on test results, use 1200 mesh sandpaper to polish the surface of the aggregate stone disc, and control the surface roughness of each aggregate stone disc to meet the requirements.

[0113] (4) Cleaning and preservation: The obtained aggregate stone disc is first washed with distilled water, then boiled with boiling water for 10min, and then placed in a 100℃ oven for about 3h to remove the water on the surface of the aggregate stone disc, and then placed in a sealed bag to prevent it from being damp, and wait for the next processing.

[0114] 1.2, making sandwich structure standard test piece

[0115] A certain amount of aggregate stone disc (also called aggregate disc) and asphalt are placed in a 165℃ oven respectively, and after constant temperature for 40min, two aggregate discs are taken out, the aggregate discs are placed in the aggregate clamp, and the aggregate discs are fixed in the aggregate clamp by screws, the aggregate clamp is connected with the rotor of the DSR tester by the rotor rod 300, the thickness of the asphalt film is controlled to be 1mm by the DSR tester, and the standard test piece is completed by scraping the sample with a heated scraper. After the standard test piece is made, it is cured in the natural environment for 24 hours, and then the pull-out test can be carried out.

[0116] Reference Figure 4In the embodiment, one aggregate disc is placed and fixed in the aggregate loading groove of the first aggregate loading platform 100, and another aggregate disc is placed and fixed in the aggregate loading groove of the second aggregate loading platform 200; then the second aggregate loading platform 200 is placed on the DSR tester, specifically, the counterbores on the clamping parts at the lower part of the second aggregate loading platform 200 are clamped on the DSR tester; then the first aggregate loading platform 100 is placed above the second aggregate loading platform 200 with a gap between the two, and then the first aggregate loading platform 100 is connected with the rotor of the DSR tester through the rotor rod 300; then the asphalt is injected between the first aggregate loading platform 100 and the second aggregate loading platform 200, and then the DSR tester is used to control the thickness of the asphalt film to be 1 mm to form the sandwich structure of aggregate-asphalt-aggregate.

[0117] The standard sample preparation method of the sandwich structure provided in the embodiment can exclude the forming conditions of the sandwich sample from bringing errors to the test, and ensure the accuracy of the test results.

[0118] S2, constructing a standard database;

[0119] (1) The interaction standard value of each standard sample is obtained by using a conventional test method for the six DSR samples in step S1.

[0120] (2) The bonding strength standard value of each standard sample is obtained by using a pull-out test for the six sandwich structure standard samples in step S1.

[0121] (3) The standard database is constructed by using the interaction standard value and the bonding strength standard value obtained above.

[0122] In the embodiment, the conventional test method is to obtain the interaction standard value between the asphalt and the filler by using the DSR. Specifically, the interaction standard value is calculated according to the following calculation formula:

[0123]

[0124] Wherein, C is the interaction, and the value of C reflects the strength of the interaction; φ is the volume fraction of the filler; is the complex shear modulus of the asphalt mortar (Pa); is the complex shear modulus of the base asphalt (Pa).

[0125] In the embodiment, the interaction standard values of the six sandwich structure standard samples are shown in Table 1.

[0126] In the embodiment, the bonding strength standard value is obtained by using a pull-out test, and the specific process is as follows:

[0127] The aggregate clamp with the sandwich structure standard specimen is fixed on the universal testing machine, that is, the rotor rod 300 is removed, the whole aggregate clamp (the sandwich structure is formed at this time) is fixed on the universal testing machine through the counterbores on the clamping parts on the upper part of the first aggregate loading platform 100 and the lower part of the second aggregate loading platform 200 respectively, and it is ensured that the center of the sandwich specimen is on the same vertical line with the center of the clamp. The main machine and the universal testing machine are turned on, the incubator is turned on, and the temperature is kept at the design temperature for 2 hours. Then, the non-metal material tensile test is set on the main machine. The sandwich structure standard specimen is separated from the interface under the action of the pulling force F, the pulling force on the pulling surface is obtained, and the standard value of the bonding strength between the asphalt and the aggregate can be calculated. The standard value of the bonding strength is calculated by the following formula:

[0128]

[0129] Wherein: σ bonding strength (the standard value here); F is the pulling force (KN); A is the contact area between the asphalt and the aggregate (m 2 ).

[0130] In the embodiment, the test operation can be accurately controlled through the above-mentioned pulling test, and the test result is accurate. This is because, compared with the traditional pulling test clamp which needs to be bonded by epoxy resin or curing agent (the bonding will make the fracture surface break at the epoxy resin or curing agent during the pulling process, resulting in invalid test data), the clamp provided in the embodiment does not need to be bonded, so that the pulling process is not easy to break, and the data is valid.

[0131] In the embodiment, the interaction standard value of the six sandwich structure standard specimens is shown in Table 1.

[0132] Table 1 Interaction standard value and bonding strength standard value

[0133]

[0134] S3, constructing a standard model of interaction and bonding strength

[0135] For the constructed standard database, the bonding strength standard value is taken as the abscissa, the interaction standard value is taken as the ordinate, and the standard curve C = b + kσ is obtained through normalization processing, that is, the standard model of interaction and bonding strength.

[0136] Specifically, the σ in Table 1 is taken as the abscissa, the C is taken as the ordinate, and then the normalization processing is performed, a curve is fitted, that is, the standard curve, which is also the standard model of interaction and bonding strength. The equation of the standard curve is:

[0137] C = -0.05628 + 1.77445σ

[0138] Wherein: C is the interaction, σ is the bond strength, 1.7744 is the slope k, and -0.05628 is the intercept b.

[0139] S4, interaction test

[0140] The sandwich structure of the test sample is taken, the bond strength test value is obtained by the pull-out test, and then substituted into the standard curve to calculate the actual value of the interaction.

[0141] In this embodiment, the Hayun 90# matrix asphalt and aggregate (calcite, albite and quartz stone) are selected, and three test samples, i.e. 90#-calcite, 90#-albite and 90#-quartz stone, are prepared according to the standard sample preparation method in step S1. Then the bond strength test value, i.e. σ value, is obtained by the pull-out test in step S2. Then substituted into C=-0.05628+1.77445σ to calculate the actual value of the interaction, i.e. the predicted C value, as shown in Table 2.

[0142] In this embodiment, the Hayun 90# matrix asphalt and aggregate (calcite, albite and quartz stone) are also selected, and three DSR samples, i.e. 90#-calcite, 90#-albite and 90#-quartz stone, are prepared by conventional method. The interaction C value of asphalt-filler is directly tested by DSR tester, i.e. the actual measured C value, as shown in Table 2.

[0143] Table 2: actual value of interaction and interaction test value

[0144] Asphalt-aggregate σ value (MPa) Predicted C value Measured C value Haiyun 90# - calcite 0.883 1.511 1.523 Haiyun 90# - albite 0.918 1.573 1.570 Haiyun 90# - quartzite 0.725 1.230 1.258

[0145] By comparing the actual value of interaction and the interaction test value in Table 2, it can be seen that the interaction size tested by the pull-out test in this embodiment is basically close to the interaction size tested by the conventional method, which shows that the method for testing the asphalt aggregate interface interaction by the pull-out test is feasible. At the same time, compared with the existing method for obtaining the interaction size by the complex modulus of asphalt and the proportion of filler, the test method of the present application is simpler.

[0146] Further, since the Pearson correlation coefficient is the covariance of two factors, it can reflect the strength of the linear relationship between two variables, so the relationship between the interaction and the bond strength constructed in this embodiment is studied by the Pearson correlation coefficient.

[0147] The calculation method of Pearson correlation coefficient r is as follows:

[0148]

[0149] In the above formula, the variable Xi and variable Y i , set the interaction C as variable X i , then the bonding strength σ is variable Y i , i is the number of two variables, i = 1, … n; n = 6.

[0150] Wherein: x i is the i th interaction standard value, is the average value of 6 interaction standard values; y i is the i th bonding strength standard value; is the average value of 6 bonding strength standard values, and r is the Pearson correlation coefficient, which is between [-1, 1], and the sign of r indicates positive correlation and negative correlation.

[0151] Considering that the test may have variability and thus cause deviation of the analysis result, the confidence interval is adopted to verify the test analysis result.

[0152]

[0153] Wherein: is the significance level, and 0.05 is commonly used as the test; is the sample mean, which refers to the mean of all data of a single item, i.e., the average value of 6 interaction standard values; α is the confidence level, and the confidence level is is the Z value, which refers to the corresponding value of the standard normal distribution table; σ is the population standard deviation; N is the sample individual number, which is 6; is the standard error of the sample.

[0154] On this basis, the relationship between the asphalt-aggregate interface adhesion and the asphalt-filler interaction is analyzed based on the Pearson analysis method, and the correlation analysis is shown in Table 3.

[0155] Table 3 Correlation analysis of C value and σ value

[0156]

[0157] As can be seen from the data in Table 2, the relationship between the sandwich structure asphalt-aggregate interface interaction and the asphalt-aggregate interface adhesion performance is significant, which shows that the relationship constructed by the present application is scientific and reasonable. The present application studies the asphalt-aggregate interface interaction strength through a simple pull-out test, which can provide a reference for the strength of the rapid interface.

[0158] Example 2

[0159] The purpose of this embodiment is to provide a testing device for realizing the method of testing the sandwich structure asphalt-aggregate interface interaction by using the pull-out test in Example 1.

[0160] The test device provided by the embodiment comprises:

[0161] aggregate clamp: used for loading and holding aggregate;

[0162] DSR tester: used for connecting with the aggregate clamp, forming a sandwich structure standard test piece by loading asphalt between the aggregate and a sandwich structure test piece to be tested, and further used for obtaining interaction standard values of the sandwich structure standard test piece by using a conventional test method;

[0163] pull-out test device: used for performing a pull-out test on the sandwich structure standard test piece and the sandwich structure test piece to be tested by using the aggregate clamp, and obtaining corresponding bonding strength standard values and bonding strength test values; preferably, the pull-out test device is a universal testing machine;

[0164] data storage module: used for storing the obtained interaction standard values, bonding strength standard values and bonding strength test values;

[0165] data processing module: used for constructing a standard database and a standard model of interaction and bonding strength according to the interaction standard values and the bonding strength standard values, and further used for calculating an actual interaction value according to the bonding strength test values.

[0166] Referring to Figure 1 and Figure 2 , in the embodiment, the aggregate clamp comprises a first aggregate loading platform 100 and a second aggregate loading platform 200.

[0167] The first aggregate loading platform 100 comprises an upper clamping portion 120 and a lower aggregate loading portion 110, and the clamping portion 120 and the aggregate loading portion 110 are connected to form a stepped structure with a small upper part and a large lower part; an aggregate loading groove 111 is formed on the lower surface of the aggregate loading portion 110 for placing an aggregate disc; the clamping portion 120 is used for connecting with the DSR tester or the pull-out test device.

[0168] Preferably, a counterbore is formed on the upper surface of the clamping portion 120 for achieving the mounting and fixing of the clamping portion 120 (i.e. the first aggregate loading platform 100) with external equipment. Preferably, the clamping portion 120 (i.e. the first aggregate loading platform 100) is connected and fixed with the DSR tester through the counterbore, or the clamping portion 120 (i.e. the first aggregate loading platform 100) is fixed on the universal testing machine through the counterbore.

[0169] In the embodiment, the second aggregate loading platform 200 has the same structure as the first aggregate loading platform 100 and is distributed in a mirror image.

[0170] Referring to Figure 3 and Figure 4The test device further comprises a rotor rod 300; the rotor rod 300 comprises, from top to bottom, a connecting end 310, a rotating connecting rod 320 and a rotor base 330; the connecting end 310 is used to be connected with the rotor of the DSR tester; the rotor base 330 is used to be clamped with the clamping part 120 of the first aggregate loading platform 100.

[0171] In the embodiment, the clamping part 120 and the aggregate loading part 110 are both cylindrical structures, and the rotor base 330 is also a cylindrical structure.

[0172] Preferably, an aggregate loading groove 111 is formed on the lower surface of the aggregate loading part 110, and an aggregate fixing hole 112 is formed on the side wall of the aggregate loading part 110; the aggregate loading groove 111 is used to place the aggregate disc, and the aggregate disc is fixed by means of a screw passing through the aggregate fixing hole 112.

[0173] In the embodiment, in order to enhance the stability of the aggregate disc, the aggregate fixing hole 112 is a plurality of holes, and the plurality of aggregate fixing holes 112 are evenly distributed in a circle in the circumferential direction of the aggregate loading part 110.

[0174] Preferably, the aggregate fixing hole 112 is three, and it can also be four or five.

[0175] In the embodiment, an inner recessed clamping groove 331 is arranged on the lower bottom surface of the rotor base 330, and the inner diameter of the clamping groove 331 matches the outer diameter of the clamping part 120; in order to facilitate the fixation of the rotor rod 300 and the first aggregate loading platform 100, a rotor fixing hole 332 is formed on the side wall of the rotor base 330; when the clamping groove 331 is clamped on the clamping part 120, a screw passes through the rotor fixing hole 332 and contacts the outside of the clamping part 120, so as to clamp the first aggregate loading platform 100.

[0176] In the embodiment, the rotor fixing hole 332 is a plurality of holes, and the plurality of rotor fixing holes 332 are evenly distributed in a circle in the circumferential direction of the rotor base 330, so as to lock the clamping part 120 from different directions, and the rotor rod 300 and the first aggregate loading platform 100 are fixed more firmly.

[0177] Preferably, the rotor fixing hole 332 is four, and it can also be three or five.

[0178] Obviously, the above embodiments are only examples for clearly illustrating, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test, characterized in that, Includes the following steps: S1. Fabrication of standard test specimens Using the specified aggregate and asphalt types, multiple standard specimens with sandwich structures were prepared. Using the specified aggregate and asphalt types, multiple DSR samples were prepared using conventional methods. S2. Construct a standard database For the multiple DSR samples in step S1, the standard value of the interaction of each DSR sample was obtained using conventional testing methods. For the multiple sandwich-structured standard specimens in step S1, the standard values ​​of the interaction for each standard specimen are obtained using conventional testing methods. For the multiple sandwich structure standard specimens in step S1, pull-out tests were used to obtain the standard bond strength value of each standard specimen. A standard database was constructed using the standard values ​​of interaction and bond strength obtained above. S3. Construct a standard model for interaction and bond strength. For the constructed standard database, with the standard value of bond strength on the x-axis and the standard value of interaction on the y-axis, a standard curve is obtained through normalization. C = This is the standard model for interaction and bond strength: where: C For interaction, For bond strength, The slope of the standard curve. The intercept; S4, Interaction Test Take the sandwich-structured test specimen, use a pull-out test to obtain the bond strength test value, and then substitute it into the standard curve to calculate the actual value of the interaction.

2. The method for testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test according to claim 1, characterized in that, The specific process for preparing the standard specimen in step S1 is as follows: S11, Aggregate processing The aggregate is processed to obtain cylindrical aggregate flakes, which are then polished, cleaned, and dried to obtain round aggregate flakes. S12, Making standard test pieces Asphalt was added between two aggregate discs, and the thickness of the asphalt film was controlled by a dynamic shear rheometer to obtain a standard specimen with a sandwich structure, which was then cured at room temperature for 24 hours.

3. The method for testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test according to claim 2, characterized in that, The aggregate stone slabs are 25mm in diameter and 5mm in height.

4. The method for testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test according to claim 2, characterized in that, The grinding, cleaning, and drying processes are as follows: Polish the surface of the stone slab with 1200-grit sandpaper, then rinse with distilled water, then boil in boiling water for 10 minutes; finally heat at 100℃ for 3 hours.

5. The method for testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test according to claim 2, characterized in that, In step S12, the specific process for obtaining the standard specimen with the sandwich structure is as follows: Two aggregate discs and asphalt were kept at a constant temperature of 165℃ for 40 minutes. Two aggregate discs are secured in the aggregate clamp, with the two aggregate discs arranged opposite each other and a gap between them. The aggregate clamp is connected to the rotor of the DSR testing machine, and asphalt is injected between the two aggregate discs. The thickness of the asphalt film is controlled by DSR. The sample is scraped with a heated scraper to obtain a standard specimen with a sandwich structure.

6. A testing apparatus for implementing the method of testing the interfacial interaction of asphalt aggregates in a sandwich structure using a pull-out test as described in claim 5, characterized in that, The testing apparatus includes: Aggregate clamps: used for loading and holding aggregates; DSR testing machine: used to connect with aggregate clamps to add asphalt between aggregates to form standard specimens with a sandwich structure and test specimens with a sandwich structure; also used to obtain the standard interaction values ​​of standard specimens with a sandwich structure using conventional testing methods; Pull-out testing device: used to perform pull-out tests on standard specimens and test specimens of sandwich structure formed by aggregate clamps to obtain the corresponding standard value and test value of bond strength; Data storage module: used to store the acquired standard values ​​of interaction, standard values ​​of bond strength, and test values ​​of bond strength; The data processing module is used to construct a standard database and a standard model of interaction and bond strength based on the standard values ​​of interaction and bond strength; it is also used to calculate the actual value of interaction based on the bond strength test value.

7. The testing apparatus according to claim 6, characterized in that, The aggregate clamp includes a first aggregate loading platform (100) and a second aggregate loading platform (200); The first material loading platform (100) includes an upper clamping part (120) and a lower material loading part (110), and the clamping part (120) and the material loading part (110) are connected to form a stepped structure that is smaller at the top and larger at the bottom; The lower surface of the aggregate loading part (110) is provided with an aggregate loading groove (111) for placing aggregate discs; the clamping part (120) is used to connect with a DSR testing machine or a pull-out testing device. The structure of the second aggregate loading platform (200) is the same as that of the first aggregate loading platform (100) and is mirrored.

8. The testing apparatus according to claim 7, characterized in that, The testing device also includes a rotor rod (300); the rotor rod (300) includes a connecting end (310), a rotating connecting rod (320), and a rotor base (330) connected sequentially from top to bottom. The connecting end (310) is used to connect with the rotor of the DSR testing machine; the rotor base (330) is used to engage with the clamping part (120) of the first aggregate loading table (100).

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