Method and device for testing interface interaction of asphalt aggregate with sandwich structure by utilizing pull-out test

Abstract

The invention belongs to the technical field of road construction materials, and relates to a method and a device for testing sandwich structure asphalt aggregate interface interaction by using a pull-out test, and the method comprises the following steps: S1, manufacturing a plurality of sandwich structure standard test pieces by using set aggregate types and asphalt types; s2, acquiring an interaction standard value and a bonding strength standard value, and constructing a standard database; s3, constructing a standard model of the interaction and the bonding strength by taking the bonding strength standard value as a horizontal coordinate and the interaction standard value as a vertical coordinate according to the constructed standard database; and S4, manufacturing a to-be-tested test piece with a sandwich structure, obtaining a bonding strength test value, substituting the bonding strength test value into the interaction and bonding strength standard model, and calculating to obtain an actual interaction value. According to the method, the interface interaction of the asphalt aggregate with the sandwich structure is tested through the pull-out test, so that the interaction test is simpler, and the interaction performance between the asphalt-aggregate interfaces can be well reflected.

Description

Technical Field

[0001] The invention belongs to the technical field of road construction materials, and relates to a method and a device for testing the interface interaction of asphalt aggregates in a sandwich structure by using a pull-out test. Background Art

[0002] Asphalt pavement is the main type of high-grade road. However, with the increase of service life, the continuous increase of traffic volume, the overloading of trucks and the change of environment, asphalt pavement will continue to suffer from diseases, which will affect the road performance. For example, asphalt pavement will suffer from water damage, rutting, cracks and other diseases. These road diseases may affect the road performance and driving comfort at the least, or even affect the road driving safety at the most. Therefore, improving the road performance and life of asphalt pavement is an urgent issue to be solved in road engineering.

[0003] At present, a lot of research has been conducted on asphalt pavement-related diseases, and the results show that its damage is closely related to the properties of the asphalt-aggregate interface. The interfacial 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 destroyed, the stability of the asphalt mixture is reduced and its overall performance becomes weaker. In the process of asphalt mortar formation, asphalt is redistributed on the filler surface due to the interaction between the asphalt-filler interface. The stronger the interaction, the denser the structure between the asphalt-filler interface, and the better the physical and mechanical properties, resulting in better stability of the asphalt mixture; at the same time, from the perspective of interfacial adhesion, the bonding strength between the asphalt-aggregate interface has a greater correlation with the overall stability of the mixture. Generally, the higher the bonding strength of the asphalt-aggregate interface, the stronger the water stability and anti-rutting performance of the mixture, and the better the overall strength and structure, thereby ensuring that the road has a longer service life and better service quality. At present, the interaction is investigated from the dimension of the interaction between asphalt and filler, while the interfacial adhesion (bonding strength) is investigated from the dimension of the interaction between asphalt and aggregate. The separate analysis of the two factors ignores the relationship between the interaction and the bonding strength, resulting in a poor reflection of the performance of 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 through multiple influencing factors such as the complex modulus of the asphalt and the proportion of the filler, which makes the test of the interaction cumbersome. Summary of the invention

[0004] In view of the technical problems of separate analysis of existing interaction and bonding strength and cumbersome test process of interaction, the present invention provides a method and device for testing the interface interaction of asphalt aggregates in a sandwich structure by using a pull-out test.

[0005] The present invention constructs a standard model of interaction and bonding strength by establishing a standard database of sandwich structure asphalt aggregates, and tests the interface interaction of sandwich structure asphalt aggregates through a pull-out test, which makes the test of interaction simpler; it also constructs the correlation between interaction and bonding strength, which can well reflect the performance of the interaction between the asphalt-aggregate interface.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for testing the interface interaction of asphalt aggregate in a sandwich structure by using a pull-out test comprises the following steps:

[0008] S1. Make standard test pieces

[0009] Using the set aggregate type and asphalt type, multiple standard specimens of sandwich structure are made;

[0010] Using the set aggregate type and asphalt type, multiple DSR specimens were prepared using conventional methods;

[0011] S2. Build a standard database

[0012] For the multiple DSR samples in step S1, a conventional testing method is used to obtain the interaction standard value of each DSR sample;

[0013] For the multiple sandwich structure standard specimens in step S1, a conventional testing method is used to obtain the interaction standard value of each standard specimen;

[0014] For the multiple standard specimens of the sandwich structure in step S1, a pull-out test is performed to obtain a standard value of the bonding strength of each standard specimen;

[0015] A standard database is constructed using the interaction standard values ​​and bonding strength standard values ​​obtained above;

[0016] S3. Standard model for interaction and bond strength

[0017] For the constructed standard database, the standard value of bonding strength is taken as the horizontal coordinate and the standard value of interaction is taken as the vertical coordinate. Through normalization processing, the standard curve C=b+kσ is obtained, which is the standard model of interaction and bonding strength: where: C is the interaction, σ is the bonding strength, k is the slope, and b is the intercept;

[0018] S4. Interaction test

[0019] Take the test specimens of the sandwich structure, use the 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.

[0020] It is further defined that the specific process of preparing the standard test piece in step S1 is:

[0021] S11. Aggregate processing

[0022] The aggregate is processed to obtain cylindrical aggregate stone pieces, which are then polished, cleaned, and dried to obtain aggregate discs;

[0023] S12. Make standard test pieces

[0024] 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 h.

[0025] It is further defined that the size of the aggregate stone pieces is: 25 mm in diameter and 5 mm in height.

[0026] It is further defined that the process of polishing, cleaning and drying is:

[0027] The surface of the stone was polished with 1200-grit sandpaper, then rinsed with distilled water, boiled in boiling water for 10 min, and finally heated at 100 °C for 3 h.

[0028] It is further defined that in step S12, the specific process of obtaining the standard test piece of the sandwich structure is:

[0029] The two aggregate discs and asphalt were kept at a constant temperature of 165°C for 40 min;

[0030] Fix two aggregate discs in the fixture accordingly, arrange the two aggregate discs opposite to each other, and leave a gap between them. Connect the fixture to the DSR rotor, inject asphalt between the two aggregate discs, use DSR to control the thickness of the asphalt film, and scrape the sample with a heated scraper to obtain a standard specimen with a sandwich structure.

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

[0032] Aggregate clamp: used to load and support aggregate;

[0033] DSR testing machine: used to connect with the aggregate fixture to add asphalt between aggregates to form a standard specimen of sandwich structure and a specimen to be tested of sandwich structure; also used to obtain the interaction standard value of the standard specimen of sandwich structure by conventional testing methods;

[0034] Pull-out test device: used to perform pull-out test on the standard specimen of the formed sandwich structure and the specimen to be tested of the sandwich structure by using the aggregate fixture, and obtain the corresponding standard value of bonding strength and test value of bonding strength;

[0035] Data storage module: used for storing the acquired interaction standard value, bonding strength standard value and bonding strength test value;

[0036] Data processing module: used to construct a standard database and a standard model of interaction and bonding strength based on the standard values ​​of interaction and bonding strength; also used to calculate the actual value of interaction based on the test value of bonding strength.

[0037] It is further defined that the aggregate fixture includes a first aggregate loading station and a second aggregate loading station;

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

[0039] An aggregate loading groove is provided on the lower surface of the aggregate loading portion for placing aggregate discs; the clamping portion is used to connect with a DSR testing machine or a pull-out testing device;

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

[0041] It is further defined that the test device further comprises a rotor rod; the rotor rod comprises a connecting end portion, a rotating connecting rod and a rotor base connected in sequence from top to bottom;

[0042] The connecting end portion is used to be connected to the rotor of the DSR testing machine; and the rotor base is used to be clamped with the clamping portion of the first aggregate loading platform.

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

[0044] 1. The present invention establishes a standard database of sandwich structure asphalt aggregates, and then constructs a standard model of interaction and bonding strength. The interface interaction of sandwich structure asphalt aggregates is tested by a pull-out test, making the test of interaction simpler; the correlation between interaction and bonding strength is also constructed, which can well reflect the performance of the interaction between the asphalt-aggregate interface.

[0045] 2. The standard model of interaction and bonding strength constructed by the present invention establishes a functional relationship for predicting and analyzing the interfacial adhesion strength and interaction. Compared with the existing rheological method for testing the interaction, the operation process of the pull-out test is simple and the testing method is scientific and reasonable.

[0046] 3. The test method provided by the present invention tests the strength of the asphalt aggregate interface interaction in the sandwich structure through a simple pull-out test, providing a reference for quickly evaluating the strength of the interface action.

[0047] 4. The present invention performs correlation and significance analysis on the constructed standard model of interaction and bonding strength, indicating that the constructed standard model is scientific and reasonable, and the interaction of the asphalt aggregate interface can be accurately tested through the pull-out test. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of the main view of the aggregate clamp structure provided by the present invention;

[0049] Figure 2 for Figure 1 A top view schematic diagram of

[0050] Figure 3 is a schematic diagram of the rotor rod;

[0051] Figure 4 This is the structural diagram of the connection between the aggregate fixture and the rotor;

[0052] in:

[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-connecting end; 320-rotating connecting rod; 330-rotor base; 331-slot; 332-rotor fixing hole. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] The present invention provides a method for testing the interface interaction of asphalt aggregates in a sandwich structure by using a pull-out test, comprising the following steps:

[0056] S1. Make standard test pieces

[0057] Using the set aggregate type and asphalt type, a number of standard specimens of sandwich structures are made.

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

[0059] S11. Aggregate processing

[0060] The aggregate is processed to obtain cylindrical aggregate stone pieces, which are then polished, cleaned and dried to obtain aggregate discs.

[0061] Preferably, the size of the aggregate stone pieces is: 25 mm in diameter and 5 mm in height.

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

[0063] The surface of the stone was polished with 1200-grit sandpaper, then rinsed with distilled water, boiled in boiling water for 10 min, and finally heated at 100 °C for 3 h.

[0064] S12. Make standard test pieces

[0065] 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 h.

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

[0067] The two aggregate discs and asphalt were kept at a constant temperature of 165°C for 40 min;

[0068] Fix two aggregate discs in the fixture accordingly, arrange the two aggregate discs opposite to each other, and leave a gap between them. Connect the fixture to the DSR rotor, inject asphalt between the two aggregate discs, use DSR to control the thickness of the asphalt film, and scrape the sample with a heated scraper to obtain a standard specimen with a sandwich structure.

[0069] Preferably, the clamp includes a first clamp and a second clamp; the first clamp and the second clamp are both stepped structures with a small upper part and a large lower part; a first groove is opened on the lower surface of the first clamp, and a second groove is opened on the lower surface of the second clamp, and the size of the first groove and the size of the second groove both match the size of the aggregate disc; the first groove and the second groove are used to place two aggregate discs respectively; the first groove and the second groove are arranged opposite to each other, and the upper part of the first clamp and the upper part of the second clamp are respectively connected to the DSR rotor.

[0070] Since the existing method of controlling the thickness of the asphalt film by applying an external load is mainly based on experience, the thickness of the asphalt film cannot be guaranteed each time, and it is difficult to control its uniformity when applying it consistently. In addition, the film thickness control cannot be performed accurately at the micron level, resulting in a large error in the interface mechanical test. In the present invention, the thickness of the asphalt film can be accurately controlled by combining the fixture and DSR.

[0071] In this embodiment, a plurality of DSR specimens are prepared by conventional methods using set aggregate types and asphalt types.

[0072] S2. Build a standard database

[0073] S21. For the multiple DSR samples in step S1, a conventional testing method is used to obtain the interaction standard value of each DSR sample.

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

[0075]

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

[0077] S22. For the plurality of standard test pieces of the sandwich structure in step S1, a pull-out test is performed to obtain the standard value of the bonding strength of each standard test piece.

[0078] In the present invention, the pull-out test is used to obtain the standard value of the bonding strength and the following formula is used for calculation:

[0079]

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

[0081] A standard database is constructed using the interaction standard values ​​and bonding strength standard values ​​obtained above.

[0082] S3. Standard model for interaction and bond strength

[0083] For the constructed standard database, the standard value of bonding strength is used as the horizontal coordinate and the standard value of interaction is used as the vertical coordinate. Through normalization processing, the standard curve C=b+kσ is obtained, which is the standard model of interaction and bonding strength: where: 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] Take the test specimens of the sandwich structure, use the 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.

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

[0087] The method provided by the present invention is described in detail below with reference to specific embodiments.

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

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

[0090] Example 1

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

[0092] S1. Make standard test pieces

[0093] Using the set aggregate type and asphalt type, multiple DSR specimens were prepared using conventional methods.

[0094] Using the set aggregate type and asphalt type, a number of standard specimens of sandwich structures are made.

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

[0096] According to the above aggregate type and asphalt type design, a total of 6 DSR specimens and 6 standard specimens of sandwich structure were made, namely: 70# matrix asphalt-calcite, 70# matrix asphalt-albite, 70# matrix asphalt-quartz, 90# matrix asphalt-calcite, 90# matrix asphalt-albite and 90# matrix asphalt-quartz.

[0097] In this embodiment, the preparation method of the DSR sample refers to the highway engineering asphalt and asphalt mixture test procedures. Specifically, a 25mm rotor and 1mm thickness DSR frequency sweep test is used.

[0098] In this embodiment, in order to produce the standard specimen of the above-mentioned sandwich structure, this embodiment also provides an aggregate clamp and a rotor rod, which are connected to a 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. Not only is the asphalt film applied evenly, but the thickness of the asphalt film can be controlled to the micron level. The test error is extremely small, ensuring accuracy.

[0099] See also Figure 1 and Figure 2 The material collection fixture includes a first material collection loading station 100 and a second material collection loading station 200 .

[0100] In this embodiment, the first aggregate loading platform 100 is a stepped columnar structure with a small top and a large bottom. Specifically, the first aggregate loading platform 100 includes 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 an integrated structure. The clamping portion 120 and the aggregate loading portion 110 are both cylindrical structures. A countersunk hole is provided on the upper surface of the clamping portion 120 for mounting and fixing with external equipment.

[0101] An aggregate loading groove 111 is provided on the lower surface of the aggregate loading portion 110 , and an aggregate fixing hole 112 is provided on the side wall of the aggregate loading portion 110 . The aggregate loading groove 111 is used to place aggregate discs, and screws are passed through the aggregate fixing holes 112 to fix the aggregate discs.

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

[0103] Preferably, the number of aggregate fixing holes 112 is three, or may be four or five.

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

[0105] See also Figure 3 and Figure 4 In this embodiment, the rotor rod 300 includes a connecting end 310, a rotating connecting rod 320 and a rotor base 330 which are connected in sequence from top to bottom. The rotor base 330 is a cylindrical structure. The connecting end 310 is used to connect with the rotor of the DSR test machine. A concave slot 331 is arranged on the lower bottom surface of the rotor base 330. The inner diameter of the slot 331 matches the outer diameter of the clamping portion 120. When the rotor base 330 is clamped on the clamping portion 120, the bottom end of the rotating connecting rod 320 is clamped in the countersunk hole on the upper surface of the clamping portion 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 opened on the side wall of the rotor base 330. When the slot 331 is clamped on the clamping portion 120, the screw contacts the outside of the clamping portion 120 through the rotor fixing hole 332, thereby clamping the first aggregate loading platform 100.

[0106] In this embodiment, there are multiple rotor fixing holes 332, which are evenly distributed in a circle on the circumference of the rotor base 330, and the clamping part 120 is locked from different directions, so that the rotor rod 300 and the first aggregate loading platform 100 are fixed more firmly.

[0107] Preferably, there are four rotor fixing holes 332 , and may also be three or five.

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

[0109] 1.1 Aggregate discs

[0110] (1) Making stone columns: The aggregate is processed into a size of 100 mm × 100 mm × 20 mm, and then a core drilling machine is used to obtain an aggregate stone column (cylindrical) with a diameter of 25 mm.

[0111] (2) Making stone chips: Use a cutting machine to cut the prepared aggregate stone columns to obtain aggregate stone chips (cylindrical) with a height of 5 mm.

[0112] (3) Aggregate surface treatment: In order to reduce the influence of aggregate surface roughness on the test results, 1200-grit sandpaper was used to grind the surface of the aggregate stone pieces, and the surface roughness of each aggregate stone piece was controlled to meet the requirements.

[0113] (4) Cleaning and preservation: The aggregate chips are first rinsed with distilled water, then boiled in boiling water for 10 minutes to remove dust from the surface of the aggregate chips, and then placed in an oven at 100°C for about 3 hours to remove moisture from the surface of the aggregate chips. They are then placed in a sealed bag to prevent them from getting damp and awaiting the next step of processing.

[0114] 1.2. Making standard specimens of sandwich structure

[0115] A certain number of aggregate stone chips (also called aggregate discs) and asphalt are placed in an oven at 165°C for 40 minutes, then two aggregate discs are taken out and placed in an aggregate fixture. The aggregate discs are fixed in the aggregate fixture with screws, and the aggregate fixture is connected to the rotor of the DSR test machine through the rotor rod 300. The DSR test machine is used to control the thickness of the asphalt film to 1mm. The standard specimen is scraped with a heated scraper to complete the preparation. After the standard specimen is prepared and cured in a natural environment for 24 hours, the pull-out test can be carried out.

[0116] See also Figure 4In this embodiment, an 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 testing machine, specifically, the second aggregate loading platform 200 is clamped on the DSR testing machine through the countersunk hole on the clamping part at the lower part; then the first aggregate loading platform 100 is placed directly above the second aggregate loading platform 200, with a gap between the two, and then the first aggregate loading platform 100 is connected to the rotor of the DSR testing machine through the rotor rod 300; asphalt is injected between the first aggregate loading platform 100 and the second aggregate loading platform 200, and then the DSR testing machine is used to control the asphalt film thickness to 1 mm to form an aggregate-asphalt-aggregate sandwich structure.

[0117] The standard test piece preparation method of the sandwich structure provided in this embodiment can eliminate the error caused by the molding conditions of the sandwich test piece to the test, thereby ensuring the accuracy of the test results.

[0118] S2, build a standard database;

[0119] (1) For the six DSR specimens in step S1, a conventional test method is used to obtain the interaction standard value of each standard specimen.

[0120] (2) For the six standard specimens of the sandwich structure in step S1, a pull-out test is performed to obtain the standard value of the bonding strength of each standard specimen.

[0121] (3) Construct a standard database using the interaction standard values ​​and bonding strength standard values ​​obtained above.

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

[0123]

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

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

[0126] In this embodiment, a pull-out test is used to obtain the standard value of the bonding strength, and the specific process is as follows:

[0127] Fix the aggregate fixture with the standard specimen of the sandwich structure on the universal testing machine, that is, remove the rotor rod 300, and fix the entire aggregate fixture (which has formed a sandwich structure at this time) on the universal testing machine through the countersunk holes on the clamping part of the upper part of the first aggregate loading platform 100 and the countersunk holes on the clamping part of the lower part of the second aggregate loading platform 200, respectively, to ensure that the center of the sandwich specimen and the center of the fixture are on the same vertical line. Turn on the host and the universal testing machine, turn on the insulation box, keep it warm at the design temperature for 2 hours, and then set the non-metallic material tensile test on the host. The standard specimen of the sandwich structure is separated from the interface under the action of the pull-out force F. The pull-out force on the pull-out surface can be used to calculate the standard value of the bonding strength between asphalt and aggregate. The standard value of the bonding strength is calculated using the following formula:

[0128]

[0129] Where: σ is the bond strength (here is the standard value); F is the pull-out force (KN); A is the contact area between asphalt and aggregate (m 2 ).

[0130] In this embodiment, through the above-mentioned pull-out test, the test operation can be accurately controlled to ensure the accuracy of the test results. This is because, compared with the traditional pull-out test fixture that needs to be bonded with epoxy resin or curing agent (bonding will cause the fracture surface to break at the epoxy resin or curing agent during the pulling process, resulting in invalid test data), the fixture provided in this embodiment does not need to be bonded, so it is not easy to break during the pulling process, ensuring the validity of the data.

[0131] In this embodiment, the interaction standard values ​​of the six standard specimens of the sandwich structure are shown in Table 1.

[0132] Table 1 Standard values ​​of interaction and bond strength

[0133]

[0134] S3. Standard model for interaction and bond strength

[0135] For the constructed standard database, the standard value of bonding strength is used as the horizontal coordinate and the standard value of interaction is used as the vertical coordinate. Through normalization processing, the standard curve C=b+kσ is obtained, which is the standard model of interaction and bonding strength.

[0136] Specifically, take σ in Table 1 as the horizontal coordinate and C as the vertical coordinate, and then perform normalization processing to fit a curve, which is the standard curve, and is also the standard model of interaction and bonding strength. The equation of the standard curve is:

[0137] C=-0.05628+1.77445σ

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

[0139] S4. Interaction test

[0140] Take the test specimens of the sandwich structure, use the 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.

[0141] In this embodiment, Haiyun 90# matrix asphalt and aggregates (calcite, albite and quartz) are selected, and three test specimens to be tested are prepared, namely 90#-calcite, 90#-albite and 90#-quartz, respectively, with reference to the preparation method of the standard specimen in step S1. Then, the bond strength test value is obtained by referring to the pull-out test method in step S2, that is, the σ value is shown in Table 2. Then, the actual value of the interaction is calculated by substituting it into C=-0.05628+1.77445σ, that is, the predicted C value, which is shown in Table 2.

[0142] In this embodiment, Haiyun 90# matrix asphalt and aggregates (calcite, albite and quartz) were also selected, and three DSR samples were prepared by conventional methods, namely 90#-calcite, 90#-albite and 90#-quartz. The asphalt-filler interaction C value was directly tested using a DSR test machine, that is, the measured C value is shown in Table 2.

[0143] Table 2 Calculated actual interaction values ​​and interaction test values

[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#-Quartz Stone 0.725 1.230 1.258

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

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

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

[0148]

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

[0150] Where: x i is the standard value of the ith interaction, is the average of the six interaction standard values; y i is the standard value of the i-th bonding strength; is the average of the six standard values ​​of bonding strength, r is the Pearson correlation coefficient, and its value is between [-1, 1]. The positive and negative signs of r indicate positive correlation and negative correlation.

[0151] Taking into account the possible variability in the test and thus the deviation of the analysis results, the confidence interval was used to verify the test analysis results.

[0152]

[0153] in: is the significance level, 0.05 is often used as the test; is the sample mean, which refers to the mean of all data of a single item, that is, the average of the six 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 number of sample individuals, which is 6; is the sample standard error.

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

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

[0156]

[0157] From the data in Table 2, it can be seen that there is a significant relationship between the asphalt-aggregate interface interaction of the sandwich structure and the asphalt-aggregate interface adhesion performance, indicating that the relationship constructed by the present invention is scientific and reasonable. The present invention 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 action.

[0158] Example 2

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

[0160] The testing device provided in this embodiment includes:

[0161] Aggregate clamp: used to load and support aggregate;

[0162] DSR testing machine: used to connect with the aggregate fixture to add asphalt between aggregates to form a standard specimen of sandwich structure and a specimen to be tested of sandwich structure; also used to obtain the interaction standard value of the standard specimen of sandwich structure by conventional testing methods;

[0163] Pull-out test device: used to perform a pull-out test on the standard specimen of the formed sandwich structure and the specimen to be tested of the sandwich structure using a material collection fixture to obtain the corresponding standard value of bonding strength and the test value of bonding strength; preferably, the pull-out test device is a universal testing machine;

[0164] Data storage module: used for storing the acquired interaction standard value, bonding strength standard value and bonding strength test value;

[0165] Data processing module: used to construct a standard database and a standard model of interaction and bonding strength based on the standard values ​​of interaction and bonding strength; also used to calculate the actual value of interaction based on the test value of bonding strength.

[0166] See also Figure 1 and Figure 2 In this embodiment, the material collection fixture includes a first material collection loading platform 100 and a second material collection loading platform 200 .

[0167] The first aggregate loading platform 100 includes 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 portion and a large lower portion; an aggregate loading groove 111 is provided on the lower surface of the aggregate loading portion 110 for placing aggregate discs; the clamping portion 120 is used to connect with a DSR testing machine or a pulling test device.

[0168] Preferably, a countersunk hole is provided on the upper surface of the clamping part 120 to realize the installation and fixation of the clamping part 120 (that is, the first aggregate loading platform 100) and the external equipment. Preferably, the clamping part 120 (that is, the first aggregate loading platform 100) is connected and fixed to the DSR testing machine through the countersunk hole, and the clamping part 120 (that is, the first aggregate loading platform 100) can also be fixed to the universal testing machine through the countersunk hole.

[0169] In this embodiment, the structure of the second material collection loading platform 200 is the same as that of the first material collection loading platform 100 and is distributed in a mirror image.

[0170] See also Figure 3 and Figure 4The test 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 in sequence 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 clamp with the clamping portion 120 of the first aggregate loading platform 100.

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

[0172] Preferably, an aggregate loading groove 111 is opened on the lower surface of the aggregate loading part 110, and an aggregate fixing hole 112 is opened on the side wall of the aggregate loading part 110. The aggregate loading groove 111 is used to place aggregate discs, and screws are used to pass through the aggregate fixing holes 112 to fix the aggregate discs.

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

[0174] Preferably, the number of aggregate fixing holes 112 is three, or may be four or five.

[0175] In this embodiment, an inwardly concave slot 331 is provided on the lower bottom surface of the rotor base 330, and the inner diameter of the slot 331 matches the outer diameter of the clamping portion 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 opened on the side wall of the rotor base 330, and when the slot 331 is stuck on the clamping portion 120, the screw contacts the outside of the clamping portion 120 through the rotor fixing hole 332, thereby clamping the first aggregate loading platform 100.

[0176] In this embodiment, there are multiple rotor fixing holes 332, which are evenly distributed in a circle on the circumference of the rotor base 330, and the clamping part 120 is locked from different directions, so that the rotor rod 300 and the first aggregate loading platform 100 are fixed more firmly.

[0177] Preferably, there are four rotor fixing holes 332 , and may also be three or five.

[0178] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A method for testing the interface interaction of asphalt aggregates in a sandwich structure by using a pull-out test, characterized in that: The following steps are involved: S1. Make standard test pieces Using the set aggregate type and asphalt type, multiple standard specimens of sandwich structure are made; Using the set aggregate type and asphalt type, multiple DSR specimens were prepared using conventional methods; S2. Build a standard database For the multiple DSR samples in step S1, a conventional testing method is used to obtain the interaction standard value of each DSR sample; For the multiple sandwich structure standard specimens in step S1, a conventional testing method is used to obtain the interaction standard value of each standard specimen; For the multiple standard specimens of the sandwich structure in step S1, a pull-out test is performed to obtain a standard value of the bonding strength of each standard specimen; A standard database is constructed using the interaction standard values ​​and bonding strength standard values ​​obtained above; S3. Standard model for interaction and bond strength For the constructed standard database, the standard value of bonding strength is taken as the horizontal coordinate and the standard value of interaction is taken as the vertical coordinate. Through normalization processing, the standard curve C=b+kσ is obtained, which is the standard model of interaction and bonding strength: where: C is the interaction, σ is the bonding strength, k is the slope of the standard curve, and b is the intercept; S4. Interaction test Take the test specimens of the sandwich structure, use the 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 interface interaction of sandwich structure asphalt aggregate by using a pull-out test according to claim 1, characterized in that: The specific process of making the standard test piece in step S1 is: S11. Aggregate processing The aggregate is processed to obtain cylindrical aggregate stone pieces, which are then polished, cleaned, and dried to obtain aggregate discs; S12. Make 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 h.

3. The method for testing the interface interaction of sandwich structure asphalt aggregate by using a pull-out test according to claim 2, characterized in that: The size of the aggregate stone pieces is: 25mm in diameter and 5mm in height.

4. The method for testing the interface interaction of sandwich structure asphalt aggregate by using a pull-out test according to claim 2, characterized in that: The process of grinding, cleaning and drying is as follows: The surface of the stone was polished with 1200-grit sandpaper, then rinsed with distilled water, boiled in boiling water for 10 min, and finally heated at 100 °C for 3 h.

5. The method for testing the interface interaction of sandwich structure asphalt aggregate by using a pull-out test according to claim 2, characterized in that: In step S12, the specific process of obtaining the standard test piece of the sandwich structure is: The two aggregate discs and asphalt were kept at a constant temperature of 165°C for 40 min; Fix two aggregate discs in the aggregate fixture accordingly. The two aggregate discs are arranged opposite to each other with a gap between them. Connect the aggregate fixture to the rotor of the DSR testing machine. Inject asphalt between the two aggregate discs. Use DSR to control the thickness of the asphalt film. Use a heated scraper to scrape the sample to obtain a standard specimen with a sandwich structure.

6. A testing device for implementing the method of testing the asphalt aggregate interface interaction of a sandwich structure by using a pull-out test as claimed in claim 5, characterized in that: The testing device comprises: Aggregate clamp: used to load and support aggregate; DSR testing machine: used to connect with the aggregate fixture to add asphalt between aggregates to form a standard specimen of sandwich structure and a specimen to be tested of sandwich structure; also used to obtain the interaction standard value of the standard specimen of sandwich structure by conventional testing methods; Pull-out test device: used to perform pull-out test on the standard specimen of the formed sandwich structure and the specimen to be tested of the sandwich structure by using the aggregate fixture, and obtain the corresponding standard value of bonding strength and test value of bonding strength; Data storage module: used for storing the acquired interaction standard value, bonding strength standard value and bonding strength test value; Data processing module: used to construct a standard database and a standard model of interaction and bonding strength based on the standard values ​​of interaction and bonding strength; also used to calculate the actual value of interaction based on the test value of bonding strength.

7. The testing device according to claim 6, characterized in that: The material collection fixture comprises a first material collection loading platform (100) and a second material collection loading platform (200); The first aggregate loading platform (100) comprises an upper clamping portion (120) and a lower aggregate loading portion (110), wherein the clamping portion (120) and the aggregate loading portion (110) are connected to form a stepped structure with a small top and a large bottom. An aggregate loading groove (111) is provided on the lower surface of the aggregate loading portion (110) for placing aggregate discs; the clamping portion (120) is used to connect to a DSR testing machine or a pulling test device; The structure of the second aggregate loading platform (200) is the same as that of the first aggregate loading platform (100) and is distributed in a mirror image.

8. The testing device according to claim 7, characterized in that: The testing device further comprises a rotor rod (300); the rotor rod (300) comprises a connecting end (310), a rotating connecting rod (320) and a rotor base (330) which are sequentially connected from top to bottom; The connecting end portion (310) is used to be connected to the rotor of the DSR testing machine; and the rotor base (330) is used to be clamped with the clamping portion (120) of the first aggregate loading platform (100).

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