Method for evaluating anti-cracking performance of asphalt stress absorbing layer and computer equipment

Abstract

The application discloses a kind of anti-cracking performance evaluation method and computer equipment for asphalt stress absorbing layer, it is related to pavement engineering technical field, the method includes: stress absorbing layer test piece is carried out oblique shear test, and index information in the process of oblique shear test is collected, the index information includes shear angle, stress load, vertical displacement, lateral displacement, interlayer dislocation displacement and stress absorbing layer adhesion force;According to the index information, the interlayer adhesion coefficient and interlayer stress absorbing coefficient of the stress absorbing layer test piece are calculated;According to the interlayer adhesion coefficient and interlayer stress absorbing coefficient, the anti-cracking performance of the stress absorbing layer test piece is evaluated.The application can introduce the interlayer adhesion coefficient and interlayer stress absorbing coefficient of stress absorbing layer test piece, and accurately evaluate the anti-cracking performance of asphalt stress absorbing layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pavement engineering, and in particular to a crack resistance evaluation method for asphalt stress absorbing layer and computer equipment. BACKGROUND

[0002] Reflective cracking is one of the most common problems between asphalt surface and semi-rigid base and between old road and asphalt overlay. Setting stress absorbing layer can effectively delay the occurrence of reflective cracking, but its interlayer bonding performance and crack resistance still need to be further improved. Therefore, it is essential to seek an effective method for evaluating the crack resistance of stress absorbing layer to prevent and control pavement reflective cracking.

[0003] The existing method for evaluating the crack resistance of stress absorbing layer is generally to directly evaluate the mechanical indexes obtained by carrying out direct shear test, low-temperature half-circle bending test and interlayer pull-out test, but the existing crack resistance evaluation indexes are insufficient and unsystematic, and the effect is not significant when applied to actual engineering.

[0004] Therefore, it is urgent to invent an intuitive, accurate and effective evaluation method for the crack resistance of asphalt stress absorbing layer. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a crack resistance evaluation method for asphalt stress absorbing layer and computer equipment, which can introduce interlayer bonding coefficient and interlayer stress absorbing coefficient to accurately evaluate the crack resistance of asphalt stress absorbing layer.

[0006] To solve the above technical problems, the present application provides a crack resistance evaluation method for asphalt stress absorbing layer, comprising: performing oblique shear test on stress absorbing layer test piece and collecting index information in the oblique shear test process, the index information including shear angle, stress load, vertical displacement, horizontal displacement, interlayer displacement and stress absorbing layer bonding force; calculating interlayer bonding coefficient and interlayer stress absorbing coefficient of the stress absorbing layer test piece according to the index information; and evaluating the crack resistance of the stress absorbing layer test piece according to the interlayer bonding coefficient and interlayer stress absorbing coefficient.

[0007] As an improvement of the above-mentioned scheme, the step of calculating the interlayer bonding coefficient and the interlayer stress absorption coefficient of the stress absorption layer test piece according to the index information comprises: calculating the interlayer direction load according to the shear angle and the stress load; calculating the vertical displacement in the interlayer direction decomposition displacement according to the vertical displacement and the shear angle; calculating the horizontal displacement in the interlayer direction decomposition displacement according to the horizontal displacement and the shear angle; calculating the stress absorption displacement according to the vertical displacement in the interlayer direction decomposition displacement, the horizontal displacement in the interlayer direction decomposition displacement and the interlayer displacement; calculating the interlayer bonding coefficient of the stress absorption layer test piece according to the stress absorption layer bonding force, the stress absorption displacement, the interlayer direction load and the vertical displacement in the interlayer direction decomposition displacement; and calculating the interlayer stress absorption coefficient of the stress absorption layer test piece according to the stress absorption displacement, the vertical displacement in the interlayer direction decomposition displacement and the horizontal displacement in the interlayer direction decomposition displacement.

[0008] As an improvement of the above-mentioned scheme, the step of calculating the interlayer bonding coefficient and the interlayer stress absorption coefficient of the stress absorption layer test piece according to the index information comprises:

[0009] According to the formula F ’ = F x sin a, the interlayer direction load F is calculated ’ , wherein a is the shear angle and F is the stress load.

[0010] According to the formula s1 = L1 x sin a, the vertical displacement in the interlayer direction decomposition displacement s1 is calculated, wherein L1 is the vertical displacement.

[0011] According to the formula s2 = L2 x cos a, the horizontal displacement in the interlayer direction decomposition displacement s2 is calculated, wherein L2 is the horizontal displacement.

[0012] According to the formula Δx = s1 + s2 - x, the stress absorption displacement Δx is calculated, wherein x is the interlayer displacement.

[0013] According to the formula , the interlayer bonding coefficient K1 of the stress absorption layer test piece is calculated, wherein F t is the stress absorption layer bonding force.

[0014] According to the formula , the interlayer stress absorption coefficient K2 of the stress absorption layer test piece is calculated.

[0015] As an improvement of the above-mentioned scheme, the interlayer bonding coefficient and the interlayer stress absorption coefficient are positively correlated with the anti-cracking performance.

[0016] As an improvement of the above-mentioned scheme, the step of evaluating the crack resistance of the stress absorbing layer test piece according to the interlayer bonding coefficient and the interlayer stress absorbing coefficient comprises: when the interlayer stress absorbing coefficient is greater than a first absorbing threshold and the interlayer bonding coefficient is greater than or equal to a second bonding threshold, or the interlayer stress absorbing coefficient is greater than or equal to the second absorbing threshold and the interlayer bonding coefficient is greater than a first bonding threshold, then the crack resistance of the stress absorbing layer test piece is "good", the first absorbing threshold is greater than the second absorbing threshold, and the first bonding threshold is greater than the second bonding threshold; when the interlayer stress absorbing coefficient is less than the second absorbing threshold and the interlayer bonding coefficient is less than or equal to the first bonding threshold, or the interlayer stress absorbing coefficient is less than or equal to the first absorbing threshold and the interlayer bonding coefficient is less than the second bonding threshold, then the crack resistance of the stress absorbing layer test piece is "general"; otherwise, the crack resistance of the stress absorbing layer test piece is "better".

[0017] As an improvement of the above-mentioned scheme, the forming step of the stress absorbing layer test piece comprises: constructing an asphalt mixture plate-shaped test piece; spreading a stress absorbing layer on the asphalt mixture plate-shaped test piece; sequentially performing standing and heat preservation treatment on the asphalt mixture plate-shaped test piece after spreading the stress absorbing layer; uniformly paving asphalt mixture on the stress absorbing layer of the asphalt mixture plate-shaped test piece after heat preservation treatment, and rolling and forming; sequentially performing standing and demolding treatment on the asphalt mixture plate-shaped test piece after rolling and forming; performing coring treatment on the asphalt mixture plate-shaped test piece after demolding to form a stress absorbing layer test piece; and performing end face flattening treatment on the stress absorbing layer test piece to make the stress absorbing layer be at the middle position of the stress absorbing layer test piece.

[0018] As an improvement of the above-mentioned scheme, the step of spreading the stress absorbing layer on the asphalt mixture plate-shaped test piece comprises: when the stress absorbing layer is a rubber asphalt stress absorbing layer, spreading rubber asphalt on the asphalt mixture plate-shaped test piece; when the stress absorbing layer is a single-layer rubber asphalt stone stress absorbing layer, spreading rubber asphalt on the asphalt mixture plate-shaped test piece, spreading rubber asphalt-precoated stones on the rubber asphalt, and lightly pressing the stones to make the stones embedded in the asphalt; when the stress absorbing layer is a double-layer rubber asphalt stone stress absorbing layer, spreading rubber asphalt on the asphalt mixture plate-shaped test piece, spreading rubber asphalt-precoated stones on the rubber asphalt, lightly pressing the stones to make the stones embedded in the asphalt, spreading rubber asphalt again, spreading rubber asphalt-precoated stones on the rubber asphalt, and lightly pressing the stones to make the stones embedded in the asphalt again.

[0019] As the improvement of the above-mentioned scheme, the step of performing the oblique shear test on the stress absorbing layer test piece and collecting index information during the oblique shear test comprises: placing the stress absorbing layer test piece in a temperature control box for heat preservation treatment; using an oblique shear test clamp to perform the oblique shear test on the stress absorbing layer test piece; during the oblique shear test, uniformly loading the stress absorbing layer test piece until the stress absorbing layer test piece reaches a target damage degree; collecting the shear angle, stress load, vertical displacement, horizontal displacement and stress absorbing layer adhesion force during the test; after the oblique shear test is completed, removing the stress absorbing layer test piece for static treatment; and measuring the interlayer displacement displacement between the upper test block and the lower test block of the stress absorbing layer test piece.

[0020] As the improvement of the above-mentioned scheme, the oblique shear test clamp comprises an upper clamp for applying pressure to the stress absorbing layer test piece, a lower clamp for supporting the stress absorbing layer test piece, a first adjusting member for adjusting the pressure angle of the upper clamp, and a second adjusting member for adjusting the support angle of the lower clamp; the upper clamp comprises a pressure plate, a top surface pressure applying part for applying pressure to the top surface of the stress absorbing layer test piece, and an upper side pressure applying part for applying pressure to the side surface of the stress absorbing layer test piece, the pressure plate is connected with the top surface pressure applying part and the upper side pressure applying part respectively, and is used for transmitting the pressure of an external pressure mechanism to the top surface pressure applying part and the upper side pressure applying part; the lower clamp comprises a support member, a bottom surface support part for positioning the bottom surface of the stress absorbing layer test piece, and a lower side support part for positioning the other side surface of the stress absorbing layer test piece, the support member is connected with the bottom surface support part and the lower side support part respectively, and is used for supporting the bottom surface support part and the lower side support part.

[0021] Correspondingly, the present application also provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method for evaluating the anti-cracking performance of the asphalt stress absorbing layer when executing the computer program.

[0022] The present application has the following advantages:

[0023] The method for evaluating the anti-cracking performance of the asphalt stress absorbing layer of the present application can monitor index information during the oblique shear test, thereby constructing the interlayer adhesion coefficient and the interlayer stress absorbing coefficient to represent the stress absorbing capacity of the stress absorbing layer and the capacity of the stress absorbing layer to absorb stress and convert it into displacement for consumption when the road surface is subjected to load.

[0024] Meanwhile, the present application can realize intuitive and efficient evaluation of the anti-cracking performance by constructing a special evaluation system based on the interlayer adhesion coefficient and the interlayer stress absorbing coefficient; the asphalt stress absorbing layer no longer needs to be subjected to the direct shear test, the low-temperature half-circle bending test and the interlayer pull-out test, which is convenient to operate and has high accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a first embodiment flow chart of the method for evaluating the anti-cracking performance of the asphalt stress absorbing layer of the present application;

[0026] Figure 2 is a front view of the oblique shear test fixture in the present application;

[0027] Figure 3 is a perspective view of the oblique shear test fixture in the present application;

[0028] Figure 4 is a force schematic diagram during the oblique shear test of the stress absorbing layer test piece in the present application;

[0029] Figure 5 is a second embodiment flow chart of the method for evaluating the anti-cracking performance of the asphalt stress absorbing layer of the present application;

[0030] Figure 6 is a schematic diagram of the change relationship between the force load, vertical displacement and lateral displacement when the test temperature is 15℃ in the present application;

[0031] Figure 7 is a schematic diagram of the change relationship between the force load, vertical displacement and lateral displacement when the test temperature is 25℃ in the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings. It is hereby declared that the up, down, left, right, front, back, inner and outer orientation words appearing or about to appear in the present application are only based on the drawings of the present application, and are not specific limitations on the present application.

[0033] Reference Figure 1 , Figure 1 shows a first embodiment flow chart of the method for evaluating the anti-cracking performance of the asphalt stress absorbing layer of the present application, which includes:

[0034] S101, performing an oblique shear test on the stress absorbing layer test piece and collecting index information during the oblique shear test;

[0035] The index information includes shear angle, force load, vertical displacement, lateral displacement, interlayer displacement and stress absorbing layer adhesion;

[0036] Correspondingly, the step of performing an oblique shear test on the stress absorbing layer test piece and collecting index information during the oblique shear test includes:

[0037] (1) placing the stress absorbing layer test piece in a temperature control box for heat preservation treatment;

[0038] The stress absorbing layer test piece is placed in a temperature control box with a pre-set temperature for heat preservation, and the heat preservation time is more than 5 hours, and the test temperature is 15°C and 25°C, but it is not limited thereto, and can be adjusted according to the actual situation.

[0039] (2) The stress absorbing layer test piece is subjected to a diagonal shear test by using a diagonal shear test fixture;

[0040] As shown in Figure 2 and Figure 3 , the diagonal shear test fixture includes an upper fixture 1 for applying pressure to the stress absorbing layer test piece 100, a lower fixture 2 for supporting the stress absorbing layer test piece 100, a first adjusting member 3 for adjusting the pressure angle of the upper fixture 1, and a second adjusting member 4 for adjusting the support angle of the lower fixture 2. Among them, the upper fixture 1 includes a pressure plate 11, a top surface pressure part 12 for applying pressure to the top surface of the stress absorbing layer test piece 100, and an upper side pressure part 13 for applying pressure to the side surface of the stress absorbing layer test piece 100, the pressure plate 11 is connected with the top surface pressure part 12 and the upper side pressure part 13 respectively, and the pressure plate 11 is used to transmit the pressure of the external pressure mechanism to the top surface pressure part 12 and the upper side pressure part 13; the lower fixture 2 includes a support member 21, a bottom surface support part 22 for positioning the bottom surface of the stress absorbing layer test piece 100, and a lower side support part 23 for positioning the other side surface of the stress absorbing layer test piece 100, the support member 21 is connected with the bottom surface support part 22 and the lower side support part 23 respectively, and is used to support the bottom surface support part 22 and the lower side support part 23.

[0041] Correspondingly, since the stress absorbing layer test piece 100 is generally a cylindrical structure, in this embodiment, the top surface pressure part 12 and the bottom surface support part 22 are designed as planar structures matching the top surface of the stress absorbing layer test piece 100 and the ground; and the upper side pressure part 13 and the lower side support part 23 are designed as arc surface structures matching the side surface of the stress absorbing layer test piece 100.

[0042] During the diagonal shear test, the diagonal shear test fixture can be arranged below the lower press head, and a roller shaft is arranged between the contact surface of the diagonal shear test fixture and the lower press head. The diagonal shear test fixture and the stress absorbing layer test piece 100 are installed on the UTM testing machine, the shear angle is 45°, and the stress absorbing layer is between the upper fixture 1 and the lower fixture 2. During the pressing process, the pressure of the lower press head is directly transmitted to the first adjusting member 3, and then to the pressure plate 11, the top surface pressure part 12 and the upper side pressure part 13, and cooperates with the lower fixture 2, so as to convert the pressure into force along the predetermined shear angle.

[0043] In this embodiment, the longitudinal section of the first adjusting member 3 and the second adjusting member 4 is a triangular structure, and the top surface of the first adjusting member 3 is parallel to the bottom surface of the second adjusting member 4. When the experiment requires adjustment of different shear angles, the first adjusting member 3 and the second adjusting member 4 with different angles can be replaced to adjust the shear angle, while ensuring that the pressure is applied vertically to the first adjusting member 3.

[0044] In addition, to accommodate stress-absorbing layer specimens 100 of different heights, an auxiliary base 5 can be added. The auxiliary base 5 can be placed between the stress-absorbing layer specimen 100 and the bottom support part 22 to facilitate oblique shear tests. Simultaneously, to accommodate stress-absorbing layer specimens 100 of different diameters, an auxiliary adapter 6 can be added. The auxiliary adapter 6 can be placed between the stress-absorbing layer specimen 100 and the upper pressure part 13 / lower support part 23 to facilitate oblique shear tests.

[0045] Furthermore, a sliding base 7 can be added. The sliding base 7 can ensure that the stress-absorbing layer specimen 100 is continuously stressed along the shear plane at a predetermined shear angle during the test.

[0046] (3) During the oblique shear test, the stress-absorbing layer specimen is loaded at a constant speed until the stress-absorbing layer specimen reaches the target degree of failure.

[0047] (4) Collect shear angle, load, vertical displacement, lateral displacement and stress absorption layer adhesion during the test;

[0048] When pressure is applied, the loading rate is 10 mm / min. The loading is uniform until the stress-absorbing layer specimen is significantly damaged. At this point, the shear angle, load, vertical displacement, lateral displacement, and adhesion of the stress-absorbing layer are recorded during the test to obtain the relationship between vertical displacement and load, and between vertical displacement and lateral displacement during the test.

[0049] (5) After the oblique shear test, the stress-absorbing layer specimen was removed for static treatment;

[0050] (6) Measure the interlayer displacement between the upper and lower test blocks of the stress-absorbing layer specimen.

[0051] After the oblique shear test, the stress-absorbing layer specimen was removed and left to stand for 1 hour. Then, the interlayer displacement between the upper and lower specimens was measured using vernier calipers.

[0052] S102, Calculate the interlaminar bonding coefficient and interlaminar stress absorption coefficient of the stress-absorbing layer specimen based on the index information;

[0053] like Figure 4 As shown, the energy conservation law during the oblique shear test of the stress-absorbing layer specimen satisfies the following formula:

[0054]

[0055] Accordingly, according to the index information, the step of calculating the interlayer bonding coefficient and the interlayer stress absorption coefficient of the stress absorption layer test piece comprises:

[0056] (1) According to the shear angle and the stress load, the interlayer direction load is calculated;

[0057] According to the following formula, the interlayer direction load F is calculated ’ :

[0058] F' = F x sin a

[0059] Wherein, a is the shear angle, F is the stress load;

[0060] (2) According to the vertical displacement and the shear angle, the vertical displacement in the interlayer direction is calculated.

[0061] According to the following formula, the vertical displacement in the interlayer direction is calculated s1

[0062] s1 = L1 x sin a

[0063] Wherein, a is the shear angle, L1 is the vertical displacement;

[0064] (3) According to the horizontal displacement and the shear angle, the horizontal displacement in the interlayer direction is calculated.

[0065] According to the following formula, the horizontal displacement in the interlayer direction is calculated s2

[0066] s2 = L2 x cos a

[0067] Wherein, a is the shear angle, L2 is the horizontal displacement;

[0068] (4) According to the vertical displacement in the interlayer direction, the horizontal displacement in the interlayer direction and the interlayer displacement, the stress absorption displacement is calculated.

[0069] According to the following formula, the stress absorption displacement Δx is calculated

[0070] Δx = s1 + s2 - x

[0071] Wherein, s1 is the vertical displacement in the interlayer direction, s2 is the horizontal displacement in the interlayer direction, and x is the interlayer displacement.

[0072] (5) According to the stress absorption layer bonding force, the stress absorption displacement, the interlayer direction load and the vertical displacement in the interlayer direction, the interlayer bonding coefficient of the stress absorption layer test piece is calculated.

[0073] The interlayer bonding coefficient K1 of the stress absorbing layer specimen is calculated according to the following formula:

[0074]

[0075] Wherein,

[0076] K1 is the interlayer bonding coefficient, and its physical meaning is the stress absorbing capacity of the stress absorbing layer when the road surface is subjected to load;

[0077] Delta x is the stress absorbing displacement, F t is the stress absorbing layer bonding force, s1 is the vertical displacement decomposed displacement in the interlayer direction, F ’ is the interlayer direction load;

[0078] (6) According to the stress absorbing displacement, the vertical displacement decomposed displacement in the interlayer direction, and the transverse displacement decomposed displacement in the interlayer direction, the interlayer stress absorbing coefficient of the stress absorbing layer specimen is calculated.

[0079] The interlayer stress absorbing coefficient K2 of the stress absorbing layer specimen is calculated according to the following formula:

[0080] K2 = ∫0 t Delta x dt / ∫0 t (s1 + s2) dt

[0081] Wherein, K2 is the interlayer stress absorbing coefficient, and its physical meaning is the stress absorbing capacity of the stress absorbing layer when the road surface is subjected to load;

[0082] Delta x is the stress absorbing displacement, s1 is the vertical displacement decomposed displacement in the interlayer direction, and s2 is the transverse displacement decomposed displacement in the interlayer direction.

[0083] Therefore, the anti-cracking performance evaluation method for the asphalt stress absorbing layer of the present application can monitor the index information in the oblique shear test process, so as to construct the interlayer bonding coefficient and the interlayer stress absorbing coefficient, so as to represent the stress absorbing capacity of the stress absorbing layer when the road surface is subjected to load and the stress absorbing capacity of the stress absorbing layer when the stress is converted into displacement for consumption;

[0084] S103, according to the interlayer bonding coefficient and the interlayer stress absorbing coefficient, the anti-cracking performance of the stress absorbing layer specimen is evaluated.

[0085] The interlayer bonding coefficient and the interlayer stress absorbing coefficient are positively correlated with the anti-cracking performance.

[0086] Specifically, the step of evaluating the anti-cracking performance of the stress absorbing layer specimen according to the interlayer bonding coefficient and the interlayer stress absorbing coefficient comprises:

[0087] (1) when the interlayer stress absorption coefficient is greater than a first absorption threshold value and the interlayer bonding coefficient is greater than or equal to a second bonding threshold value, or the interlayer stress absorption coefficient is greater than or equal to the second absorption threshold value and the interlayer bonding coefficient is greater than the first bonding threshold value, then the stress absorption layer test piece has a "good" anti-cracking performance; wherein the first absorption threshold value is greater than the second absorption threshold value, and the first bonding threshold value is greater than the second bonding threshold value;

[0088] (2) when the interlayer stress absorption coefficient is less than the second absorption threshold value and the interlayer bonding coefficient is less than or equal to the first bonding threshold value, or the interlayer stress absorption coefficient is less than or equal to the first absorption threshold value and the interlayer bonding coefficient is less than the second bonding threshold value, then the stress absorption layer test piece has a "general" anti-cracking performance;

[0089] (3) otherwise, the stress absorption layer test piece has a "better" anti-cracking performance

[0090] In the embodiment, the first absorption threshold value can be set to 0.6, the second absorption threshold value can be set to 0.3, the first bonding threshold value can be set to 1, and the second bonding threshold value can be set to 0.5, so that:

[0091] (1) when K2> 0.6 and K1≥ 0.5, or K2≥ 0.3 and K1> 1, then the asphalt stress absorption layer has a "good" anti-cracking performance;

[0092] (2) when K2< 0.3 and K1≤ 1, or K2≤ 0.6 and K1< 0.5, then the asphalt stress absorption layer has a "general" anti-cracking performance;

[0093] (3) when K2< 0.3 and K1> 1, or 0.3≤ K2≤ 0.6 and 0.5≤ K1≤ 1, or K2> 0.6 and K1< 0.5, then the asphalt stress absorption layer has a "better" anti-cracking performance.

[0094] The corresponding evaluation indexes are shown in Table 1 as follows:

[0095] Evaluation index [K1 < 0.5] [0.5≤ K1≤ 1] [K1 > 1] [K2 < 0.3] Good Good Good 0.3 < K2 < 0.6 Good Good Good [K2 > 0.6] Good Good Good

[0096] It should be noted that when the anti-cracking performance of the stress absorption layer test piece is of the same level, the anti-cracking performance is ranked based on the interlayer stress absorption coefficient K2 and the interlayer bonding coefficient K1.

[0097] Therefore, the present application constructs a special evaluation system based on the interlayer bonding coefficient and the interlayer stress absorption coefficient, and can realize intuitive and efficient evaluation of the anti-cracking performance; the asphalt stress absorption layer no longer needs to be subjected to a direct shear test, a low-temperature half-circle bending test and an interlayer pulling test, and the operation is convenient and the accuracy is high.

[0098] Referring to Figure 5 , Figure 5A second embodiment flow chart of the anti-cracking performance evaluation method of the present application for asphalt stress absorbing layer is shown, which comprises:

[0099] S201, constructing a stress absorbing layer test piece;

[0100] Correspondingly, the forming step of the stress absorbing layer test piece comprises:

[0101] (1) Constructing an asphalt mixture plate-shaped test piece;

[0102] According to the "Highway Engineering Asphalt and Asphalt Mixture Test Procedures" T0703-2011, a wheel roller is used to form an asphalt mixture plate-shaped test piece with a size of 300mm x 300mm x 55mm.

[0103] Correspondingly, the gradation of the asphalt mixture plate-shaped test piece is shown in Table 2 below:

[0104] Table 2

[0105]

[0106] At the same time, the oil-stone ratio and volume index of the asphalt mixture plate-shaped test piece are shown in Table 3 below:

[0107] Table 3

[0108]

[0109] (2) Spraying stress absorbing layer on the asphalt mixture plate-shaped test piece;

[0110] It should be noted that the stress absorbing layer type is divided into three types: rubber asphalt stress absorbing layer, single-layer rubber asphalt gravel stress absorbing layer and double-layer rubber asphalt gravel stress absorbing layer. The three types of stress absorbing layer will be described in detail as follows:

[0111] I. Rubber asphalt stress absorbing layer

[0112] When the stress absorbing layer is a rubber asphalt stress absorbing layer, when spraying the stress absorbing layer on the asphalt mixture plate-shaped test piece: directly spraying rubber asphalt on the asphalt mixture plate-shaped test piece.

[0113] For example, constructing an asphalt mixture plate-shaped test piece 1: immediately after the asphalt mixture plate-shaped test piece is formed, 2.0kg / m 3 of rubber asphalt is sprayed on the plate-shaped test piece.

[0114] II. Single-layer rubber asphalt gravel stress absorbing layer

[0115] When the stress absorbing layer is a single-layer rubber asphalt chip stress absorbing layer, the stress absorbing layer is spread on the asphalt mixture plate-shaped test piece as follows: the rubber asphalt is first spread on the asphalt mixture plate-shaped test piece, and then the chips pre-wrapped with rubber asphalt are spread on the rubber asphalt, and the chips are lightly pressed to embed the chips into the asphalt;

[0116] For example, the asphalt mixture plate-shaped test piece 2 is constructed as follows: immediately after the asphalt mixture plate-shaped test piece is formed, 2.0 kg / m 3 of 180°C hot rubber asphalt is spread on the plate-shaped test piece, and then 10-15 mm single-size chips pre-wrapped with rubber asphalt are uniformly spread on the rubber asphalt according to 80% of the spreading area, and the chips are lightly pressed with an iron block to embed the chips into the asphalt.

[0117] Three, double-layer rubber asphalt chip stress absorbing layer

[0118] When the stress absorbing layer is a double-layer rubber asphalt chip stress absorbing layer, the stress absorbing layer is spread on the asphalt mixture plate-shaped test piece as follows: the rubber asphalt is first spread on the asphalt mixture plate-shaped test piece, and then the chips pre-wrapped with rubber asphalt are spread on the rubber asphalt, and the chips are lightly pressed to embed the chips into the asphalt, and then the rubber asphalt is spread again, the chips pre-wrapped with rubber asphalt are spread on the rubber asphalt, and the chips are lightly pressed again to embed the chips into the asphalt.

[0119] For example, the asphalt mixture plate-shaped test piece 3 is constructed as follows: immediately after the asphalt mixture plate-shaped test piece is formed, 2.0 kg / m 3 of 180°C hot rubber asphalt is spread on the plate-shaped test piece, and then 10-15 mm single-size chips pre-wrapped with rubber asphalt are uniformly spread on the rubber asphalt according to 80% of the spreading area, and the chips are lightly pressed with an iron block to embed the chips into the asphalt; and then 2.0 kg / m 3 of 180°C hot rubber asphalt is spread again, and 5-10 mm single-size chips pre-wrapped with rubber asphalt are uniformly spread on the rubber asphalt according to 80% of the spreading area, and the chips are lightly pressed with an iron block to embed the chips into the asphalt.

[0120] (3) The asphalt mixture plate-shaped test piece after the stress absorbing layer is spread is sequentially subjected to standing and heat preservation treatment;

[0121] The asphalt mixture plate-shaped test piece is placed together with the test mold at room temperature for 48 hours, and then is placed in a 60°C oven for heat preservation for 5 hours.

[0122] (4) The asphalt mixture is uniformly paved on the stress absorbing layer of the asphalt mixture plate-shaped test piece after the heat preservation treatment, and is rolled and formed;

[0123] The mixed asphalt mixture is immediately uniformly paved above the stress absorbing layer, and is rolled and compacted with a wheel compactor.

[0124] (5) The asphalt mixture plate-shaped test piece after roller compaction is sequentially subjected to standing and demolding treatment;

[0125] The asphalt mixture plate-shaped test piece is placed together with the test mold at room temperature, and after 48 hours, demolding is performed.

[0126] (6) The asphalt mixture plate-shaped test piece after demolding is subjected to coring treatment to form a stress absorbing layer test piece;

[0127] A cylindrical stress absorbing layer test piece is obtained using a core drill.

[0128] (7) The stress absorbing layer test piece is subjected to end face grinding treatment to make the stress absorbing layer in the middle position of the stress absorbing layer test piece.

[0129] The stress absorbing layer test piece is subjected to end face grinding treatment, and the size of the stress absorbing layer test piece is controlled to be and the stress absorbing layer is ensured to be in the middle position of the stress absorbing layer test piece.

[0130] S202, the stress absorbing layer test piece is subjected to oblique shear test, and the index information in the process of oblique shear test is collected;

[0131] For example, after the asphalt mixture plate-shaped test pieces 1 (rubber asphalt stress absorbing layer), 2 (single-layer rubber asphalt gravel stress absorbing layer) and 3 (double-layer rubber asphalt gravel stress absorbing layer) are respectively constructed according to step S201, the stress absorbing layer test pieces are subjected to oblique shear test according to step S201, the index information at temperatures of 15℃ and 25℃ can be obtained, and the change relationship between the stress load, vertical displacement and lateral displacement in the test process is obtained (see Figure 6 and Figure 7 wherein, line a represents the change relationship of test piece 1, line b represents the change relationship of test piece 2, and line c represents the change relationship of test piece 3);

[0132] Correspondingly, the index information when the test piece stops loading is as shown in Table 4:

[0133] Table 4

[0134]

[0135] S203, according to the index information, the interlayer bonding coefficient and the interlayer stress absorbing coefficient of the stress absorbing layer test piece are calculated;

[0136] Correspondingly, according to step S203, the interlayer bonding coefficient and the interlayer stress absorbing coefficient of the stress absorbing layer test piece at 15℃ can be calculated:

[0137] For test piece 1: K1=0.59, K2=0.16; it can be obtained that the crack resistance is “general”;

[0138] For the test piece 2: K1=0.60, K2=0.42; it can be obtained that the crack resistance is 'better';

[0139] For the test piece 3: K1=0.77, K2=0.63; it can be obtained that the crack resistance is 'good';

[0140] Similarly, according to step S203, the interlayer bonding coefficient and the interlayer stress absorption coefficient of the stress absorbing layer test piece at 25 DEG C can be calculated:

[0141] For the test piece 1: K1=0.50, K2=0.38; it can be obtained that the crack resistance is 'better';

[0142] For the test piece 2: K1=0.65, K2=0.48; it can be obtained that the crack resistance is 'better';

[0143] For the test piece 3: K1=1.49, K2=0.68. It can be obtained that the crack resistance is 'good';

[0144] Among them, the crack resistance of the test piece 1 and the test piece 2 is the same level, at this time, K2 of the test piece 1 is 0.38, K2 of the test piece 2 is 0.48, so the test piece 2 is better than the test piece 1.

[0145] S204, evaluating the crack resistance of the stress absorbing layer test piece according to the interlayer bonding coefficient and the interlayer stress absorption coefficient.

[0146] From the above, under the same temperature condition, in the embodiment, the interlayer bonding coefficient is sorted as: test piece 3> test piece 2> test piece 1, and the interlayer stress absorption coefficient is sorted as: test piece 3> test piece 2> test piece 1. Therefore, the double-layer rubber asphalt gravel stress absorbing layer has the best crack resistance, the single-layer rubber asphalt gravel stress absorbing layer is the second, and the rubber asphalt stress absorbing layer is the lowest.

[0147] It should be noted that the double-layer rubber asphalt gravel stress absorbing layer is spread with asphalt containing graded gravel, and has greater elastic capacity, so the crack resistance is better; the rubber asphalt stress absorbing layer is just the opposite, and is not spread with gravel, and has poorer elastic capacity, so the elastic stress absorbing capacity is poorer when bearing the shear load.

[0148] Therefore, the evaluation result of the crack resistance is consistent with the theoretical result, and the application is suitable for the intuitive, accurate and effective evaluation method of the crack resistance of the asphalt stress absorbing layer.

[0149] Correspondingly, the application discloses a computer device, which comprises a memory and a processor, and the memory stores a computer program, wherein the processor realizes the steps of the crack resistance evaluation method for the asphalt stress absorbing layer when executing the computer program.

[0150] The above is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements are also considered to be within the scope of the present application.

Claims

1. A method for evaluating the crack resistance of asphalt stress-absorbing layers, characterized in that, include: Oblique shear tests were conducted on the stress-absorbing layer specimens, and index information during the oblique shear test process was collected. The index information included shear angle, load, vertical displacement, lateral displacement, interlayer displacement, and stress-absorbing layer adhesion. Based on the aforementioned index information, calculate the interlayer bonding coefficient and interlayer stress absorption coefficient of the stress-absorbing layer specimen; The crack resistance of the stress-absorbing layer specimen is evaluated based on the interlaminar bond coefficient and the interlaminar stress absorption coefficient. The step of calculating the interlaminar bonding coefficient and interlaminar stress absorption coefficient of the stress-absorbing layer specimen based on the index information includes: according to the formula F ’ =F ×sin α Calculate the inter-story load F ’ ,in, α For the shearing angle, F For the load being applied; according to the formula s 1 = L 1×sin α Calculate the vertical displacement in the inter-story direction. s 1, among which, L 1 represents the vertical displacement; according to the formula s 2 = L 2×cos α Calculate the lateral displacement in the inter-story direction. s 2, of which, L 2 represents the lateral displacement; according to the formula Δ x = s 1+ s 2- x Calculate the stress absorption displacement Δ x ,in, x This refers to the inter-story drift displacement; according to the formula... Calculate the interlaminar bond coefficient of the stress-absorbing layer specimen. K 1, among which, F t This refers to the adhesion force of the stress-absorbing layer; according to the formula... Calculate the interlaminar stress absorption coefficient of the stress-absorbing layer specimen. K 2.

2. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 1, characterized in that, The step of calculating the interlaminar bonding coefficient and interlaminar stress absorption coefficient of the stress-absorbing layer specimen based on the index information includes: Calculate the interlayer load based on the shear angle and the applied load; Based on the vertical displacement and shear angle, calculate the decomposed vertical displacement in the interlayer direction; Based on the lateral displacement and shear angle, the lateral displacement is decomposed into displacements in the interlayer direction. Based on the decomposition of vertical displacement in the inter-story direction, the decomposition of lateral displacement in the inter-story direction, and the inter-story slip displacement, the stress absorption displacement is calculated. The interlayer bond coefficient of the stress-absorbing layer specimen is calculated based on the bonding force of the stress-absorbing layer, the stress-absorbing displacement, the interlayer load, and the vertical displacement decomposed into displacements in the interlayer direction. The interlayer stress absorption coefficient of the stress-absorbing layer specimen is calculated based on the stress-absorbing displacement, the vertical displacement decomposed into interlayer displacement, and the lateral displacement decomposed into interlayer displacement.

3. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 1, characterized in that, The interlayer bonding coefficient and interlayer stress absorption coefficient are positively correlated with the crack resistance performance.

4. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 1 or 3, characterized in that, The step of evaluating the crack resistance of the stress-absorbing layer specimen based on the interlaminar bond coefficient and the interlaminar stress absorption coefficient includes: When the interlaminar stress absorption coefficient is greater than the first absorption threshold and the interlaminar bond coefficient is greater than or equal to the second bond threshold, or when the interlaminar stress absorption coefficient is greater than or equal to the second absorption threshold and the interlaminar bond coefficient is greater than the first bond threshold, the crack resistance of the stress absorption layer specimen is "good", the first absorption threshold is greater than the second absorption threshold, and the first bond threshold is greater than the second bond threshold. When the interlaminar stress absorption coefficient is less than the second absorption threshold and the interlaminar bond coefficient is less than or equal to the first bond threshold, or when the interlaminar stress absorption coefficient is less than or equal to the first absorption threshold and the interlaminar bond coefficient is less than the second bond threshold, the crack resistance of the stress absorption layer specimen is "average". Otherwise, the crack resistance of the stress-absorbing layer specimen is "good".

5. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 1, characterized in that, The molding steps of the stress-absorbing layer specimen include: Constructing asphalt mixture slab specimens; A stress-absorbing layer was spread on the asphalt mixture plate specimen; The asphalt mixture plate specimens after the stress-absorbing layer was applied were subjected to static and heat-insulating treatments in sequence. The asphalt mixture is evenly laid onto the stress-absorbing layer of the asphalt mixture plate specimen after thermal insulation treatment, and then rolled into shape. The asphalt mixture slab specimens after compaction were subjected to static treatment and demolding in sequence. Core sampling was performed on the demolded asphalt mixture plate specimens to form stress-absorbing layer specimens; The stress-absorbing layer specimen is subjected to end face grinding to ensure that the stress-absorbing layer is positioned in the middle of the specimen.

6. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 5, characterized in that, The step of applying the stress-absorbing layer onto the asphalt mixture plate specimen includes: When the stress-absorbing layer is a rubber asphalt stress-absorbing layer, rubber asphalt is spread on the asphalt mixture plate specimen. When the stress-absorbing layer is a single-layer rubber asphalt crushed stone stress-absorbing layer, the rubber asphalt is spread on the asphalt mixture plate specimen, the crushed stone pre-coated with rubber asphalt is spread on the rubber asphalt, and the crushed stone is lightly pressed to embed the crushed stone into the asphalt. When the stress-absorbing layer is a double-layer rubber asphalt crushed stone stress-absorbing layer, rubber asphalt is spread on the asphalt mixture plate specimen, crushed stone pre-coated with rubber asphalt is spread on the rubber asphalt, the crushed stone is lightly pressed to embed it into the asphalt, rubber asphalt is spread again, crushed stone pre-coated with rubber asphalt is spread on the rubber asphalt, and the crushed stone is lightly pressed to embed it into the asphalt.

7. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 1, characterized in that, The steps of conducting oblique shear tests on stress-absorbing layer specimens and collecting index information during the oblique shear test process include: The stress-absorbing layer specimen was placed in a temperature-controlled chamber for heat preservation treatment; The stress-absorbing layer specimen was subjected to a slant shear test using a slant shear test fixture. During the oblique shear test, the stress-absorbing layer specimen is subjected to uniform loading until the stress-absorbing layer specimen reaches the target degree of failure. Shear angle, load, vertical displacement, lateral displacement, and stress-absorbing layer adhesion were collected during the test. After the oblique shear test, the stress-absorbing layer specimen was removed and left to stand for static treatment. The interlayer displacement between the upper and lower test blocks of the stress-absorbing layer specimen was measured.

8. The method for evaluating the crack resistance of asphalt stress-absorbing layers as described in claim 7, characterized in that, The oblique shear test fixture includes an upper fixture for applying pressure to the stress-absorbing layer specimen, a lower fixture for supporting the stress-absorbing layer specimen, a first adjusting member for adjusting the pressure angle of the upper fixture, and a second adjusting member for adjusting the support angle of the lower fixture; The upper clamp includes a pressure plate, a top surface pressure part for applying pressure to the top surface of the stress-absorbing layer specimen, and an upper side pressure part for applying pressure to the side surface of the stress-absorbing layer specimen. The pressure plate is connected to the top surface pressure part and the upper side pressure part respectively, and is used to transmit the pressure of the external pressure mechanism to the top surface pressure part and the upper side pressure part. The lower clamp includes a support member, a bottom support portion for positioning the bottom surface of the stress-absorbing layer specimen, and a lower support portion for positioning the other side of the stress-absorbing layer specimen. The support member is connected to the bottom support portion and the lower support portion respectively, and is used to support the bottom support portion and the lower support portion.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

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