Aggregate-asphalt film-aggregate sample preparation device for shear test

Abstract

The utility model discloses an aggregate-asphalt film-aggregate sample preparation device for a shear test, which comprises an outer frame and a temperature and humidity control box positioned in the outer frame, and a linear driving mechanism and a loading rod driven by the linear driving mechanism to move up and down are arranged on the outer frame. The lower part of the loading rod penetrates through an opening in the top of the temperature and humidity control box and extends into the temperature and humidity control box, an upper clamp is fixed at the tail end of the loading rod, the upper clamp is used for fixing an upper aggregate sample, a lower clamp is fixed in the temperature and humidity control box, the lower clamp is used for fixing a lower aggregate sample, and the upper clamp is used for clamping the upper aggregate sample. The axis of the upper clamp, the axis of the lower clamp and the axis of the loading rod are located on the same straight line, a side opening is formed in one side of the temperature and humidity control box, an asphalt filler can penetrate through the side opening, and a detachable sealing plug is arranged at the side opening. According to the utility model, the thickness of the asphalt film and the temperature and humidity in the sample curing process can be more accurately controlled.

Description

TECHNICAL FIELD

[0001] The utility model relates to road construction engineering technical field especially, it is a kind of aggregate-pitch film-aggregate sample preparation device for shear test. BACKGROUND

[0002] Asphalt pavement has the advantages of good antiskid performance, comfortable and stable driving, high strength, long service life and the like, and is widely used in road construction. The normal driving and parking of road traffic tools will bring intermittent repeated action of dynamic and static load to asphalt pavement, and such action is easy to generate shear stress in asphalt mixture constituting pavement. When the shear stress in pavement structure layer exceeds the strength range that asphalt mixture can bear, the flowability of asphalt mixture will be accumulated year by year with time, which will lead to shear deformation of asphalt pavement, and finally cause road diseases such as crack, bump, rut and pit, thereby reducing driving comfort and safety, and even bringing major safety hazards to people's travel, and also bringing adverse effects to national economy and personal safety.

[0003] Affected by construction and environment and other factors, the interface between asphalt and aggregate is often not completely bonded, but is in a weak bonding state, which has great influence on the key mechanical properties of the whole asphalt mixture. The road condition investigation result shows that various diseases of asphalt mixture in road engineering are often developed and evolved from the slight damage of asphalt-aggregate interface, and the asphalt-aggregate interface region is also considered as the weakest link of the strength of asphalt mixture. Therefore, correctly understanding the adhesion performance of asphalt-aggregate interface is one of the keys to solving the diseases of asphalt pavement engineering.

[0004] One of the ways to test the mechanical properties of asphalt-aggregate interface is to obtain shear mechanical data under different conditions through shear test. The test used in interface shear test is usually called "sandwich" sample, which is composed of cylindrical aggregate a-pitch film b-cylindrical aggregate a, as shown in Figure 1 During the test process, one side of the cylindrical aggregate a is fixed, and shear force is applied to the other side of the cylindrical aggregate a, so as to measure the shear mechanical properties of asphalt-aggregate interface, and the force schematic diagram is shown in Figure 2 .

[0005] There is a lack of a standardized sample preparation device in the prior art, which can control the thickness of pitch film b, and the temperature and humidity in the preparation and maintenance process of "sandwich" sample are uncontrollable, so that the shear test result deviates. UTILITY MODEL CONTENT

[0006] The utility model aims at the technical defects existing in the prior art, and provides a kind of aggregate-pitch film-aggregate sample preparation device for shear test.

[0007] The technical scheme adopted by the utility model for realizing the purposes is:

[0008] A kind of aggregate-asphalt film-aggregate sample preparation device for shear test, including outer frame and temperature and humidity control box located in outer frame, linear drive mechanism is equipped on the outer frame and the loading rod that is driven and moves up and down by linear drive mechanism, the lower part of the loading rod passes through the top opening of the temperature and humidity control box and extends into the temperature and humidity control box, the end of the loading rod is fixed with upper clamp, the upper clamp is used to fix upper aggregate sample, lower clamp is fixed in the temperature and humidity control box, the lower clamp is used to fix lower aggregate sample, the upper clamp, the lower clamp and the shaft of loading rod are located on the same straight line, one side of the temperature and humidity control box is provided with side opening for asphalt filler to pass through, the side opening is provided with detachable sealing plug.

[0009] In the above technical scheme, the upper clamp and the lower clamp are all three-jaw clamps.

[0010] In the above technical scheme, the position of the top opening and the side opening is wrapped with elastic rubber film.

[0011] In the above technical scheme, the linear drive mechanism is a servo control system, and the servo control system is in communication connection with a computer.

[0012] In the above technical scheme, the temperature and humidity control box is provided with a heat preservation resin glass door, and the temperature and humidity control box is provided with a control interface to set the temperature and humidity in the temperature and humidity control box.

[0013] In the above technical scheme, the material of the outer frame is stainless steel or aluminum.

[0014] In the above technical scheme, the asphalt filler is a syringe.

[0015] Compared with the prior art, the utility model has the beneficial effects that:

[0016] 1. In the utility model, the temperature and humidity control box can accurately control the temperature and humidity in the preparation and curing process of the "sandwich" sample, and can be closer to the actual situation of engineering.

[0017] 2. In the utility model, the servo control system can accurately control the thickness of the asphalt film in the "sandwich" sample through displacement control method, which is more direct and accurate than the previous load control method for controlling the thickness of the asphalt film.

[0018] 3. The sample preparation device and related test method of the utility model are standardized, and the sample preparation device of the utility model has simple structure and low processing cost, which is convenient for commercial application and promotion. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure shows a structural schematic diagram of a "sandwich" sample.

[0020] Figure 2 The figure shows a force schematic diagram of a "sandwich" sample in the process of testing the mechanical properties of asphalt-aggregate interface.

[0021] Figure 3 The figure shows a structural schematic diagram of a sample preparation device of the utility model.

[0022] In the figure: a-cylindrical aggregate, b-asphalt film;

[0023] 1-outer frame, 2-temperature and humidity control box, 3-loading rod, 4-top opening, 5-upper clamp, 6-upper aggregate sample, 7-lower clamp, 8-lower aggregate sample, 9-side opening, 10-asphalt filler, 11-servo control system, 12-control interface, 13-computer. DETAILED DESCRIPTION

[0024] The utility model will be further described in detail in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0025] Example 1

[0026] A kind of aggregate-asphalt film-aggregate sample preparation device for shear test, including outer frame 1 and the temperature and humidity control box 2 in outer frame 1, the outer frame 1 is equipped with linear drive mechanism and the loading rod 3 that is driven to move up and down by linear drive mechanism, the lower part of the loading rod 3 passes through the top opening 4 of the temperature and humidity control box 2 and extends into the temperature and humidity control box 2, the end of the loading rod 3 is fixed with upper clamp 5, and the upper clamp 5 is used to fix upper aggregate sample 6, the temperature and humidity control box 2 is fixed with lower clamp 7, and the lower clamp 7 is used to fix lower aggregate sample 8, the axis of the upper clamp 5, the lower clamp 7 and loading rod 3 is located on the same straight line, one side of the temperature and humidity control box 2 is equipped with side opening 9 for asphalt filler 10 to pass through, and the side opening 9 is equipped with detachable sealing plug.

[0027] As preferred, the upper clamp 5 and the lower clamp 7 are all three-jaw clamps, which are convenient for fixing cylindrical aggregate sample.

[0028] As preferred, the positions of the top opening 4 and the side opening 9 are wrapped with an elastic rubber film to ensure the sealing of the temperature and humidity control box 2, slow down the heat exchange with the outside world, and when the asphalt filler 10 is filled with asphalt, the sealing plug is removed, the side opening 9 of the asphalt filler 10 is inserted into the temperature and humidity control box 2, and after the asphalt is injected, the asphalt filler 10 is removed and the sealing plug is inserted into the position of the side opening 9 to ensure that the temperature and humidity in the temperature and humidity control box 2 are not affected by the outside environment.

[0029] As preferred, the linear drive mechanism is a servo control system 11, which is in communication connection with the computer 13, and the servo control system 11 can control the up-down movement of the loading rod 3, accurately control the up-down displacement distance of the loading rod 3 or the load applied by the loading rod 3. The linear drive mechanism can also use a hydraulic rod or other linear drive mechanism.

[0030] As preferred, the temperature and humidity control box 2 is provided with a heat preservation resin glass door, which is convenient for real-time observation of the internal conditions of the temperature and humidity control box 2, and the temperature and humidity control box 2 is provided with a control interface 12 to set the temperature and humidity in the temperature and humidity control box 2.

[0031] As preferred, the material of the outer frame 1 is stainless steel or aluminum, which is used to fix the linear drive mechanism and the temperature and humidity control box 2.

[0032] As preferred, the asphalt filler 10 is a syringe, which is used to inject asphalt between aggregate samples.

[0033] Example 2

[0034] The selection, ratio, test and other processes of raw materials in the test process are based on JTG-2004 "Highway Asphalt Pavement Construction Technical Specification". The "sandwich" sample preparation process and asphalt film thickness control method are as follows: the method for preparing the "sandwich" sample by using the aggregate-asphalt film-aggregate sample preparation device of example 1, including the following steps:

[0035] Step one, aggregate sample preparation:

[0036] (1) According to the engineering requirements, select the same batch of coarse stone, screen the stone without cracks, and coarsely process it into rectangular aggregate by using a stone cutting machine.

[0037] (2) Use a certain specification of diamond sand grinding disc (such as 120 mesh) to polish the surface of the coarsely processed aggregate to ensure the uniformity of the roughness of the surface of each group of test pieces. The roughness of the polished surface can be measured by a laser profilometer, and the test pieces with large roughness difference are removed. Then use a rock core drilling machine to drill a cylindrical aggregate sample with a diameter of 19mm, and after cleaning and drying, observe the surface of the aggregate to ensure that there is no crack or other damage.

[0038] Step two, control the environment of the box:

[0039] (1) After the preparation of the aggregate sample in step one, install the two aggregate samples on the upper clamp 5 and the lower clamp 7 respectively, start the servo control system 11, and let the loading rod 3 move downward under low speed conditions until the upper aggregate sample is very close to the lower aggregate sample, and observe whether the two samples are aligned vertically. If they are aligned vertically, raise the upper aggregate sample, and if they are not aligned vertically, reinstall the aggregate samples until the upper and lower aggregate samples 8 are aligned.

[0040] (2) After the upper and lower aggregate samples 8 are aligned, raise the loading rod 3 to a certain position, and then use a vernier caliper to measure the distance between the opposite surfaces of the upper and lower aggregate samples, which is recorded as H0, and clear the displacement control amount of the loading rod 3 in the servo control system 11.

[0041] (3) According to the test requirements, set the temperature and humidity control box 2 to the target temperature and humidity, and control the aggregate sample for more than 2 hours.

[0042] Step three, asphalt preparation:

[0043] (1) Prepare the asphalt mortar according to the specification.

[0044] (2) Add the asphalt mortar to the stirrer, heat and control the temperature at about 160℃, slowly add the mineral powder and other additives, and use a high-speed shearing emulsifier to stir the mixture.

[0045] (3) Observe the stirred mixture, and after three to five minutes when the asphalt and mineral powder are completely fused, the asphalt preparation is completed.

[0046] Step four, preparation of "sandwich" sample:

[0047] (1) Suck the prepared asphalt into the asphalt injector 10, extend the asphalt injector 10 into the temperature and humidity control box 2, and when the injection head reaches the upper surface of the lower aggregate, squeeze the syringe to apply a certain amount of asphalt on the surface of the lower aggregate, and then remove the asphalt injector 10.

[0048] (2) Input the displacement value H1 of the loading rod 3 in the servo control system 11, and the calculation method is:

[0049] H1 = H0 -△h

[0050] Where△h is the thickness of the asphalt film of the "sandwich" sample.

[0051] Start the loading rod 3, and the loading rod 3 stops automatically after descending to the set position.

[0052] (3) After the "sandwich" test specimen is formed, the temperature and humidity of the control box are adjusted, and the sample curing stage is started. The curing stage is not less than 24 hours, and after completion, the test specimen is placed in a self-sealing plastic bag. This is the "sandwich" test specimen used for the test.

[0053] For ease of description, spatially relative terms such as "upper", "lower", "left", "right", and the like, are used herein for the purpose of illustrating one element or feature's relationship to another element or feature as the figures are presently oriented (i.e., the relative positions of the elements as shown in the figures). It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0054] Also, the term "first" and "second" are used herein only to distinguish one element from another element with the same name, and do not necessarily require or imply any such actual relationship or order between or among the elements.

[0055] The above description is only the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the principle of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing, characterized by, The device comprises an outer frame and a temperature and humidity control box in the outer frame, the outer frame is provided with a linear drive mechanism and a loading rod driven by the linear drive mechanism to move up and down, the lower part of the loading rod extends into the temperature and humidity control box through the top opening of the temperature and humidity control box, the end of the loading rod is fixed with an upper clamp for fixing an upper aggregate sample, a lower clamp for fixing a lower aggregate sample is fixed in the temperature and humidity control box, the upper clamp, the lower clamp and the axis of the loading rod are located on the same straight line, one side of the temperature and humidity control box is provided with a side opening for the asphalt filler to pass through, and a detachable sealing plug is arranged at the side opening.

2. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing according to claim 1, characterised in that, The upper clamp and the lower clamp are both three-jaw clamps.

3. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing as claimed in claim 1, characterized in that, The positions of the top opening and the side opening are wrapped with elastic rubber membranes.

4. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing as claimed in claim 1, wherein, The linear drive mechanism is a servo control system, and the servo control system is in communication connection with a computer.

5. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing as claimed in claim 1, wherein, The temperature and humidity control box is provided with a heat preservation resin glass door, and a control interface is arranged on the temperature and humidity control box to set the temperature and humidity in the temperature and humidity control box.

6. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing as claimed in claim 1, characterized in that, The material of the outer frame is stainless steel or aluminum.

7. An aggregate-bitumen membrane-aggregate specimen preparation device for shear testing as claimed in claim 1, characterized in that, The asphalt filler is a syringe.

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