Apparatus for evaluating influence of different temperature environments on performance of asphalt concrete pavement

Abstract

The utility model discloses a device for evaluating the influence of different temperature environments on the performance of asphalt concrete pavement, which solves the problem of no relevant special equipment in the existing laboratory. The device comprises an insulation box body, a box cover, a fixing clamp, a counterweight weight, a controller, an electric heating sheet, a temperature sensor and a mechanical strain gauge. The electric heating sheet, the temperature sensor and the mechanical strain gauge are arranged in the test space. The fixing clamp holds the sample and is placed in the test space. The counterweight weight is pressed in the center position of the sample in the released state. The temperature sensor and the mechanical strain gauge are fixed on the sample and avoid the loading point of the counterweight weight. The device sets multiple test spaces with different temperatures, simultaneously performs temperature-mechanical tests on three asphalt concrete samples, and obtains corresponding test data, which has a positive significance for accurately studying and predicting the fatigue characteristics of asphalt pavement.

Description

Technical Field

[0001] This utility model relates to the technical field of testing devices for the performance effects of asphalt concrete pavement. Background Technology

[0002] In the study of the physical properties of asphalt concrete pavement, the influence mechanism of temperature on asphalt concrete pavement mainly includes high-temperature softening and low-temperature brittleness. For example, relevant literature records that high-temperature softening refers to the significant decrease in the viscosity of asphalt binder when the pavement temperature is above 60℃, leading to a decrease in the pavement's resistance to rutting and making it prone to permanent deformation. Low-temperature brittleness refers to the increase in the elastic modulus of asphalt materials and a decrease in tensile strength when the temperature is below -10℃, making them prone to thermal shrinkage cracks. However, existing equipment lacks testing devices or apparatus for different temperature ranges above 60℃. This invention focuses on the research of asphalt concrete under high-temperature conditions (above 60℃) and proposes a laboratory apparatus based on this research. Utility Model Content

[0003] To address the shortcomings of existing technologies, this invention provides a device for evaluating the effects of different temperature environments on the performance of asphalt concrete pavements, solving the problem of the lack of relevant specialized equipment in existing laboratories, and accelerating the research process through multiple sets of control experiments.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows:

[0005] An apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement includes an insulated box, a box cover, a fixing clamp, counterweights, a controller, an electric heating element, a temperature sensor, and a mechanical strain gauge. The box cover is fastened to the insulated box and has at least one test space between them. The electric heating element, temperature sensor, and mechanical strain gauge are installed within the test space, and the electric heating element, temperature sensor, and mechanical strain gauge are electrically connected to the controller on the outside of the insulated box. The fixing clamp holds the sample and places it within the test space. The sample is clamped at both ends and is in a simply supported beam state. At least one set of counterweights is movably installed on the box cover. When released, the counterweights are pressed against the center of the sample. The temperature sensor and mechanical strain gauge are fixed to the sample, avoiding the loading point of the counterweights.

[0006] Furthermore, the counterweight is fixed to the lower end of the constraint screw, which extends through the box cover to the outside of the box cover and is temporarily locked by a nut.

[0007] Furthermore, the fixing clamp consists of two L-shaped fixing blocks, upper and lower, which are fastened with fastening bolts.

[0008] Furthermore, a handle is provided at the upper fixing block of the fixing fixture.

[0009] Furthermore, a magnet is fixedly installed at the contact surface of the fixing fixture and / or the test space.

[0010] Furthermore, the electric heating element is an electric heating element composed of mica sheets and wound resistance heating wires.

[0011] Furthermore, the interior of the insulated box is divided into three test spaces by partitions, and protrusions that cooperate with the partitions are provided on the inner surface of the box cover.

[0012] Furthermore, the lid and the insulated box body are a composite structure composed of a stainless steel outer shell and an inner high-temperature resistant inorganic material.

[0013] Furthermore, the interlocking surfaces between the lid and the insulated box body are designed with a tongue and groove joint, and are locked in place by latches and hinges.

[0014] Furthermore, the controller is electrically connected to the strain acquisition instrument and power supply via an external cable.

[0015] The beneficial effects of this utility model are:

[0016] This device sets up multiple test spaces with different temperatures to simultaneously conduct temperature-mechanical tests on three asphalt concrete samples and obtain corresponding test data. This is of positive significance for accurately studying and predicting the fatigue characteristics of asphalt pavement. Attached Figure Description

[0017] Figure 1 This is a diagram showing the components of this device.

[0018] Figure 2 This is a 3D view of the insulated box.

[0019] Figure 3 This is a 3D view of the box lid.

[0020] Figure 4 This is a three-dimensional view of the sample after it has been clamped and fixed.

[0021] Figure 5 This is a cross-sectional view of the device.

[0022] In the diagram: 00, test space; 01, electric heating element; 02, temperature sensor; 03, mechanical strain gauge; 10, insulation box; 11, partition; 20, box cover; 21, weight; 22, constraint screw; 23, nut; 24, protrusion; 30, fixing fixture; 31, fixing block; 32, handle; 33, fastening bolt; 40, sample; 50, controller. Detailed Implementation

[0023] A device for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement is disclosed. Designed based on scientific research on the performance of asphalt concrete pavement, the device operates on the principle of providing a constant-temperature, heatable, sealed chamber. A sample is placed within this chamber, and its temperature is increased. A temperature sensor attached to the sample surface monitors the temperature in real time until a set temperature is reached. Heating is then stopped, and a counterweight is released to apply load to the sample for a set time. Corresponding mechanical data is generated using strain gauges attached to the sample surface. After the set time is reached, the counterweight is removed, the device is opened, the sample is taken out, and photographs are taken to inspect and record any changes in shape and cracking.

[0024] Refer to the instruction manual. Figure 1 To be continued Figure 5 A detailed description is provided. The device includes an insulated chamber 10, a lid 20, a fixing clamp 30, counterweights, a controller, a temperature sensor, and strain gauges. The insulated chamber 10 is made of composite material. Specifically, the outer shell of the insulated chamber 10 is made of stainless steel sheet, and the inner surface is covered with a high-temperature resistant inorganic material, such as aluminum silicate cotton insulation material. A partition 11 divides the internal structure of the insulated chamber into three isolated test spaces 00. A lid 20 is fastened to the top of the insulated chamber. The lid 20 has the same projected area as the insulated chamber and is also a composite structure composed of a stainless steel outer shell and an inner high-temperature resistant inorganic material. The mating surface between the lid and the insulated chamber is designed with a tongue and groove joint to ensure a tight seal.

[0025] Furthermore, a latch (not shown in the figure) is provided between the insulated box body 10 and the box cover 20. The latch is used to lock the box cover after it is closed.

[0026] Furthermore, a protrusion 24 corresponding to the partition is provided on the inner surface of the box cover 20. The protrusion and the partition are tightly fitted together, so that adjacent test spaces are isolated from each other and do not affect each other.

[0027] The following structure is set up within each test space:

[0028] Electric heating elements 01 are provided on the sides, bottom, and top of the test space 00. For example, an electric heating element is an electric heating element in which a resistance heating wire is wound around a mica plate. The aforementioned electric heating elements heat the sample inside the chamber. Furthermore, multiple electric heating elements in the test space have different heating powers. This design facilitates rapid adjustment of the temperature in different chambers.

[0029] The controller 50 is located on the outside of the insulation box. The electric heating element 01 mentioned above is electrically connected to the controller, and the controller controls the power supply and power-off of the electric heating element.

[0030] The fixing clamp 30 is provided in pairs. Each fixing clamp 30 consists of two L-shaped fixing blocks 31, which are fastened with fastening bolts 33. After fastening, the end of the asphalt concrete sample is clamped and formed as a whole. The shape of the clamped sample and the fixing clamp is shown in the reference. Figure 4 Furthermore, a handle 32 is provided on the upper fixing block of the aforementioned fixing fixture for one-handed gripping. Magnet I is provided on the lower fixing block of the fixture, and magnet II is provided on the base plate of the test space. During the process of fixing the fixing fixture 30 and the sample and placing them in the test space, the attraction force between the two magnets is used to quickly and reliably fix the fixing fixture, thus achieving both rapid placement and precise positioning, and preventing shaking.

[0031] The sample is held in a simply supported beam state after both ends are clamped.

[0032] A temperature sensor 02 and a mechanical strain gauge 03 are led out and installed on the side wall of the test space 00 via wires. The temperature sensor and the mechanical strain gauge are then attached to the surface of the specimen to obtain the temperature data and mechanical data of the specimen, respectively.

[0033] Three sets of counterweights 21 are provided inside the box cover 20. Each set of counterweights corresponds to a constraint screw 22. The constraint screw passes through the box cover mounting hole and is temporarily fastened to the outside of the box cover with a nut 23. The counterweights 21 are temporarily fixed to the inside of the box cover by the nut. After the box cover is in place, the sample in the test space is heated. After heating to the set temperature, the nut is loosened and the counterweights fall onto the sample for relevant mechanical tests.

[0034] The method of using this device is as follows:

[0035] Step 1: Prepare asphalt concrete sample 40. The sample 40 has the following dimensions: 400 mm in length, 100 mm in width, and 40 mm in thickness. Use a template to draw and mark the positions for attaching mechanical strain gauges, placing temperature sensors, and loading counterweights on the sample, and then color them for later use.

[0036] Step two: Clamp and fix both ends (length direction) of the sample 40 using the fixing clamp 30, then place it in the corresponding test space. Next, use a cotton swab soaked in a small amount of anhydrous alcohol to wipe the sample surface and apply adhesive. Adhere the mechanical strain gauge 03 to the sample surface. Simultaneously, place the temperature sensor 02 on the sample surface. Note that the positions of the mechanical strain gauge and temperature sensor should avoid the loading area of ​​the counterweight.

[0037] Step 3: Close the lid and lock it. In this state, the counterweight is suspended and does not come into contact with the sample below.

[0038] Step four: Begin the experiment. Connect the controller's external cable to the strain gauge (not shown in the diagram) and the power supply. Then, turn on the power and heat the three samples in the three test spaces separately using the electric heating elements. Once the set temperature is reached, stop heating and release the corresponding counterweights. The counterweights then load the corresponding samples, and mechanical and temperature data are recorded during this process. During this process, if the temperature sensor detects a temperature drop exceeding 1°C, heating is automatically replenished under program control, thus implementing closed-loop control.

[0039] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Without departing from the spirit of the present utility model, all modifications and improvements to the present utility model by those skilled in the art should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A device for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement, comprising an insulated box, a box cover, fixing clamps, counterweights, a controller, an electric heating element, a temperature sensor, and a mechanical strain gauge, characterized in that, The lid is fastened to the insulated box body, and there is at least one test space between the two. An electric heating element, a temperature sensor, and a mechanical strain gauge are installed in the test space. The electric heating element, temperature sensor, and mechanical strain gauge are electrically connected to a controller on the outside of the insulated box body. After the fixing clamp holds the sample, it is placed in the test space. The two ends of the sample are clamped and are in a simply supported beam state. At least one set of counterweights is movably installed on the lid. When released, the counterweights are pressed against the center position of the sample. The temperature sensor and mechanical strain gauge are fixed on the sample and avoid the loading point of the counterweights.

2. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The counterweight is fixed to the lower end of the constraint screw, which passes through the box cover and extends to the outside of the box cover and is temporarily locked by a nut.

3. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The fixing clamp consists of two L-shaped fixing blocks, which are fastened with fastening bolts.

4. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 3, characterized in that, A handle is provided at the upper fixing block of the fixing fixture.

5. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 4, characterized in that, Magnets are fixedly installed at the contact surfaces of the fixing fixture and / or the test space.

6. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The electric heating element is an electric heating element composed of mica sheets and wound resistance heating wires.

7. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The interior of the insulated box is divided into three test spaces by partitions, and protrusions that cooperate with the partitions are provided on the inner surface of the box cover.

8. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The lid and insulated box body are a composite structure consisting of a stainless steel outer shell and an inner high-temperature resistant inorganic material.

9. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The mating surfaces between the lid and the insulated box body are designed with a tongue and groove joint, and are locked in place by latches and hinges.

10. The apparatus for evaluating the effects of different temperature environments on the performance of asphalt concrete pavement according to claim 1, characterized in that, The controller is electrically connected to the strain acquisition instrument and power supply via an external cable.

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