An auxiliary device for thin layer cover interlayer bond strength test

Abstract

The utility model provides a kind of auxiliary device for interlayer bonding strength test of thin layer cover surface, comprising: thin layer cover surface test piece body;Thin layer cover surface outer mold cover is sleeved in one end of thin layer cover surface test piece body;Road surface upper layer outer mold cover is sleeved in the other end of thin layer cover surface test piece body. Thin layer cover surface test piece body is fixed by test piece fixed push-pull rod component, thin layer cover surface outer mold cover is moved down by cooperating on shear plate with external press, the interlayer bonding layer shear failure of thin layer cover surface can be made, under the action of thin layer cover surface outer mold cover and road surface upper layer outer mold cover, the both ends of thin layer cover surface test piece body can be protected, shear force can be evenly applied on cover surface layer, to make bonding interface first damage, avoid the situation that stress local concentration causes cover surface layer first and bonding interface damage, effectively improve the accuracy of cover surface layer bonding strength test.

Description

Technical Field

[0001] This utility model relates to the field of road testing technology, specifically to an auxiliary device for testing the interlayer bond strength of thin overlay. Background Technology

[0002] Thin overlay is an ultra-thin asphalt concrete wearing course technology with a thickness of 1-30 mm, mainly used to improve the surface service function of asphalt pavement and for preventive maintenance. This technology restores the function of aged asphalt by spraying penetrating agents or by using new materials such as modified asphalt and high-toughness mixtures, significantly improving the pavement's skid resistance coefficient (up to 61 BPN), crack resistance, and noise reduction effect.

[0003] In the practical application of thin-layer overlays, interlayer bonding performance is one of the key factors affecting their durability and pavement quality. Currently, the evaluation of the interlayer bonding capacity of thin-layer overlays mainly relies on the direct shear test and oblique shear test specified in the "Specifications for Design of Highway Asphalt Mixtures" (JTGF40-2017) and the "Technical Specifications for Construction of Asphalt Pavement Base Course" (JTG / TF40-2017). The direct shear test applies shear force perpendicular to the surface layer to test the shear strength between two layers of asphalt mixture, thus evaluating the bonding performance between the asphalt layer and the base or surface layer. However, existing test methods have significant shortcomings: due to the thinness of the overlay (typically about 2 cm), under vertical shear force, the overlay layer itself is prone to failure before the bonding interface, making it impossible to accurately measure the true interlayer bonding strength; existing direct shear test equipment is mainly designed for conventional asphalt mixtures and does not consider the special structural characteristics of thin-layer overlays, leading to premature breakage of the thin overlay during the test, making it difficult to effectively evaluate its bonding performance with the upper pavement layer. Therefore, there is an urgent need to develop an auxiliary device for testing the interlayer bond strength of thin-layer coatings, in order to overcome the limitations of existing testing methods in testing thin-layer materials and to support the optimization and improvement of thin-layer coating interlayer bonding technology. Utility Model Content

[0004] This invention proposes an auxiliary device for testing the interlayer bond strength of thin overlays, which solves the problem that existing direct shear test devices in related technologies are mainly designed for conventional asphalt mixtures and do not take into account the special structural characteristics of thin overlays, resulting in premature breakage of the thin overlays during the test and making it difficult to effectively evaluate their bonding performance with the upper pavement.

[0005] The technical solution of this utility model is as follows: An auxiliary device for testing the interlayer bonding strength of a thin-layer cover, comprising: a thin-layer cover test specimen body;

[0006] A thin-layer cover outer mold sleeve fitted onto one end of the thin-layer cover test piece body;

[0007] The outer mold sleeve of the road surface layer is fitted onto the other end of the thin-layer cover test piece body;

[0008] An upper shearing plate is located on the upper side of the outer mold sleeve of the thin-layer cover and is driven downward by external equipment;

[0009] A lower shearing plate is located on the lower side of the outer mold sleeve of the road surface layer and is used to support the outer mold sleeve of the road surface layer.

[0010] And a specimen fixing push-pull rod component, which is respectively located at the ends of the thin-layer overlay outer mold sleeve and the road surface surface layer outer mold sleeve, and is used to fix the thin-layer overlay outer mold sleeve and the road surface surface layer outer mold sleeve.

[0011] Preferably, the thin overlay test specimen body includes a thin overlay asphalt mixture layer, a road surface layer specimen disposed at one end of the thin overlay asphalt mixture layer, and a thin overlay interlayer bonding layer disposed between the road surface layer specimen and the thin overlay asphalt mixture layer.

[0012] Preferably, the axial thickness of the outer mold sleeve of the thin overlay is 2-3 mm less than the thickness of the thin overlay asphalt mixture layer, and the axial thickness of the outer mold sleeve of the road surface layer is 2-3 mm less than the thickness of the road surface layer specimen.

[0013] Preferably, the outer mold sleeve of the thin-layer cover is provided with a rubber sleeve one inside, and the outer mold sleeve of the road surface surface layer is provided with a rubber sleeve two inside.

[0014] Preferably, the specimen fixing push-pull rod component includes a connecting rod, an abutment plate fixedly connected to one end of the connecting rod, and a rubber pad fixedly installed on the side of the abutment plate away from the connecting rod.

[0015] The working principle and beneficial effects of this utility model are as follows:

[0016] The test is completed by sequentially placing the thin overlay outer mold sleeve and the road surface surface layer outer mold sleeve onto both ends of the thin overlay test specimen. The specimen is then fixed to an external shear fixture via a specimen fixing push-pull rod assembly. An external press then moves the upper shear plate downwards, causing the thin overlay outer mold sleeve to move downwards, thus breaking the interlayer bond layer of the thin overlay. During the test, the outer mold sleeves of the thin overlay and road surface surface layers protect both ends of the thin overlay test specimen, ensuring that the shear force is applied evenly to the overlay layer. This facilitates the initial failure of the bond interface, preventing localized stress concentration that could lead to premature failure of the bond interface and thus hindering accurate measurement of the true interlayer bond strength. This effectively improves the accuracy of the overlay bond strength test. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of this utility model;

[0019] Figure 2 This is a partial three-dimensional structural diagram of the thin-layer cover test specimen body of this utility model;

[0020] Figure 3 This is a partial three-dimensional structural diagram of the thin-layer outer mold sleeve of this utility model;

[0021] Figure 4 This is a partial three-dimensional structural diagram of the outer mold sleeve for the surface layer of the road surface according to this utility model;

[0022] Figure 5 This is a partial three-dimensional structural diagram of the push-pull rod component for fixing the specimen of this utility model.

[0023] In the figure: 1. Thin overlay test specimen body; 101. Thin overlay asphalt mixture layer; 102. Road surface layer specimen; 103. Thin overlay interlayer bonding layer; 2. Thin overlay outer mold sleeve; 201. Rubber sleeve one; 3. Road surface layer outer mold sleeve; 301. Rubber sleeve two; 4. Upper shear plate; 5. Lower shear plate; 6. Specimen fixing push-pull rod assembly; 601. Connecting rod; 602. Contact plate; 603. Rubber pad. Detailed Implementation

[0024] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.

[0025] Please see Figure 1 - Figure 5 The present invention provides an auxiliary device for testing the interlayer bonding strength of a thin-layer cover, comprising: a thin-layer cover test specimen body 1;

[0026] A thin-layer outer mold sleeve 2 is fitted onto one end of the thin-layer cover body 1;

[0027] The outer mold sleeve 3 of the road surface surface layer is fitted onto the other end of the thin-layer cover body 1;

[0028] An upper shearing plate 4 is located on the upper side of the thin-layer outer mold sleeve 2 and is driven to move downward by an external device. The upper shearing plate 4 is mounted on an external straight shearing fixture.

[0029] A lower shearing plate 5 is located on the lower side of the outer mold sleeve 3 of the road surface layer and is used to support the outer mold sleeve 3 of the road surface layer. The lower shearing plate 5 is installed on the external straight shearing fixture.

[0030] And a specimen fixing push-pull rod component 6 is provided at the ends of the thin layer overlay outer mold sleeve 2 and the road surface surface layer outer mold sleeve 3 respectively, and is used to fix the thin layer overlay outer mold sleeve 2 and the road surface surface layer outer mold sleeve 3, wherein the specimen fixing push-pull rod components 6 on both sides are installed on the two sides of the external straight shear fixture.

[0031] It should be noted that the direct shear fixture is specifically a rectangular frame that is detachably mounted on an external MTS servo press so that the MTS servo press can provide downward pressure for testing. Furthermore, the upper shear plate 4 is slidably mounted on the top of the direct shear fixture, the lower shear plate 5 is fixedly mounted on the inner bottom wall of the direct shear fixture, and the specimen fixing push-pull rod assembly 6 is movably mounted on both sides of the direct shear fixture, allowing it to move on the fixture so that the closed ends of the thin-layer cover outer mold sleeve 2 and the road surface surface layer outer mold sleeve 3 abut against each other, thereby fixing the thin-layer cover specimen body 1 on the direct shear fixture.

[0032] The thin overlay test specimen body 1 includes a thin overlay asphalt mixture layer 101, a road surface layer specimen 102 disposed at one end of the thin overlay asphalt mixture layer 101, and a thin overlay interlayer bonding layer 103 disposed between the road surface layer specimen 102 and the thin overlay asphalt mixture layer 101.

[0033] The technical solution provided in this embodiment is as follows: Before testing, a thin overlay test specimen body 1 is first prepared. A road surface layer specimen 102 is prepared by the Marshall method or rotary compaction method. After it is formed, a thin overlay interlayer bonding layer 103 (interlayer tack coat oil) is applied to one end face of the road surface layer specimen 102. Before the thin overlay interlayer bonding layer 103 is completely cured, a thin overlay asphalt mixture layer 101 is laid and compacted by a small compactor or static compaction method. After curing at room temperature for 24 hours, the thin overlay test specimen body 1 is obtained. During testing, the thin overlay outer mold sleeve 2 and the road surface layer outer mold sleeve 3 are sequentially placed on both ends of the thin overlay test specimen body 1, namely the thin overlay asphalt mixture layer 101 and the road surface layer test specimen 102. At this time, there is a gap between the thin overlay outer mold sleeve 2 and the road surface layer outer mold sleeve 3, and the thin overlay interlayer bonding layer 103 is exactly located in this gap. Then, the thin overlay test specimen body 1 is moved to the lower shear plate 5 on the direct shear fixture, and the upper shear plate 4 is brought into contact with the top surface of the thin overlay outer mold sleeve 2. At the same time, the specimen fixing push-pull rod component 6 abuts against the thin overlay outer mold sleeve 2 and the road surface layer outer mold sleeve 3 to fix the thin overlay test specimen body 1 on the direct shear fixture. Then, the upper shear plate 4 is driven downward by the external press (MTS servo press), so that the upper shear plate 4 applies the pressure of the lower press evenly to the thin overlay outer mold sleeve 2, thereby driving the thin overlay outer mold sleeve 2 to move downward. As the downward pressure increases, the thin overlay outer mold sleeve 2 and the road surface surface layer outer mold sleeve 3 move relative to each other and shear off. At this time, the thin overlay outer mold sleeve 2 causes the thin overlay asphalt mixture layer 101 inside it to separate from the thin overlay interlayer bonding layer 103, thus destroying the thin overlay interlayer bonding layer 103 (at this time, the thin overlay outer mold sleeve 2 is not completely separated from the specimen fixing push-pull rod component 6). After that, the strength test of the thin overlay interlayer bonding layer 103 can be completed by checking the value of the pressure machine. During the test, under the action of the thin overlay outer mold sleeve 2 and the road surface surface layer outer mold sleeve 3, both ends of the thin overlay specimen body 1 can be protected, so that the shear force can be evenly applied to the overlay layer, which makes it easier for the bonding interface to be destroyed first. This avoids the situation where the overlay layer is destroyed first by local stress concentration, which would lead to the inability to accurately measure the true interlayer bonding strength, thus effectively improving the accuracy of the overlay bonding strength test.

[0034] Furthermore, the axial thickness of the thin overlay outer mold sleeve 2 is 2-3 mm less than the thickness of the thin overlay asphalt mixture layer 101, and the axial thickness of the pavement surface layer outer mold sleeve 3 is 2-3 mm less than the thickness of the pavement surface layer specimen 102.

[0035] Specifically, by limiting the axial thickness of the thin overlay outer mold sleeve 2 and the road surface surface outer mold sleeve 3, it is possible to avoid their thickness being too high, which would affect the strength test of the thin overlay interlayer bonding layer 103.

[0036] Furthermore, the outer mold sleeve 2 of the thin-layer overlay is provided with a rubber sleeve 201 inside, and the outer mold sleeve 3 of the road surface surface layer is provided with a rubber sleeve 301 inside.

[0037] Specifically, by setting rubber sleeve 201 and rubber sleeve 301 inside the outer mold sleeve 2 of the thin overlay and the outer mold sleeve 3 of the road surface layer respectively, the thin overlay asphalt mixture layer 101 and the road surface layer specimen 102 can be protected during the shear test, preventing them from being damaged.

[0038] Furthermore, the specimen fixing push-pull rod component 6 includes a connecting rod 601, an abutment plate 602 fixedly connected to one end of the connecting rod 601, and a rubber pad 603 fixedly installed on the side of the abutment plate 602 away from the connecting rod 601. The connecting rod 601 is a screw with threads on its surface, which can be threaded to both sides of the external shearing fixture, and a rotating block is installed at one end of it so that rotating the connecting rod 601 can drive the abutment plate 602 to move.

[0039] Specifically, when fixing the thin-layer cover test specimen body 1, the thin-layer cover outer mold sleeve 2 and the road surface surface outer mold sleeve 3 are respectively placed on the thin-layer cover test specimen body 1, and then the whole body is moved to the lower shear plate 5 of the external direct shear fixture. The lower shear plate 5 supports the road surface surface outer mold sleeve 3. Then, the connecting rods 601 on both sides of the direct shear fixture are rotated, which drives the abutment plate 602 to move, so that the abutment plate 602 abuts against the ends of the thin-layer cover outer mold sleeve 2 and the road surface surface outer mold sleeve 3 respectively, so as to fix the thin-layer cover test specimen body 1 on the direct shear fixture, prevent it from lateral displacement during the test, and help ensure the stability of the test. Under the action of the rubber pad 603, the abutment force can be buffered to prevent the thin-layer cover outer mold sleeve 2 and the road surface surface outer mold sleeve 3 from being damaged due to excessive force.

[0040] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An auxiliary device for testing the interlayer bond strength of a thin-layer coating, characterized in that, include: Thin-layer cover test specimen body (1); A thin-layer outer mold sleeve (2) is fitted onto one end of the thin-layer outer mold body (1); The outer mold sleeve (3) of the road surface surface layer is fitted on the other end of the thin-layer cover test piece body (1); An upper shearing plate (4) is located on the upper side of the outer mold sleeve (2) of the thin layer cover and is driven to move downward by an external device. A lower shearing plate (5) is located on the underside of the outer mold sleeve (3) of the road surface layer and is used to support the outer mold sleeve (3) of the road surface layer. And a specimen fixing push-pull rod component (6) is provided at the ends of the thin layer overlay outer mold sleeve (2) and the road surface surface layer outer mold sleeve (3), respectively, and is used to fix the thin layer overlay outer mold sleeve (2) and the road surface surface layer outer mold sleeve (3).

2. The auxiliary device for testing the interlayer bond strength of a thin-layer cover according to claim 1, characterized in that, The thin overlay test specimen body (1) includes a thin overlay asphalt mixture layer (101), a road surface layer specimen (102) disposed at one end of the thin overlay asphalt mixture layer (101), and a thin overlay interlayer bonding layer (103) disposed between the road surface layer specimen (102) and the thin overlay asphalt mixture layer (101).

3. The auxiliary device for testing the interlayer bond strength of a thin-layer cover according to claim 2, characterized in that, The axial thickness of the thin overlay outer mold sleeve (2) is 2-3 mm less than the thickness of the thin overlay asphalt mixture layer (101), and the axial thickness of the road surface outer mold sleeve (3) is 2-3 mm less than the thickness of the road surface specimen (102).

4. The auxiliary device for testing the interlayer bond strength of a thin-layer cover according to claim 1, characterized in that, The thin-layer outer mold sleeve (2) is provided with a rubber sleeve one (201) inside, and the road surface outer mold sleeve (3) is provided with a rubber sleeve two (301) inside.

5. The auxiliary device for testing the interlayer bond strength of a thin-layer cover according to claim 1, characterized in that, The specimen fixing push-pull rod component (6) includes a connecting rod (601), an abutment plate (602) fixedly connected to one end of the connecting rod (601), and a rubber pad (603) fixedly installed on the side of the abutment plate (602) away from the connecting rod (601).

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