CN202330192U - Test device capable of simulating actual road surface cracks through reflection cracks - Google Patents

Abstract

The utility model discloses a test device capable of simulating actual road surface cracks through reflection cracks, which comprises a test machine (7), a measurement system (8), an environment box (3), a data collection system (6) and a bituminous road surface simulation platform (9) arranged in the environment box (3). The test device has the advantages of being convenient to operate, high in data accuracy and suitable for the technical field of crack resistance researches on engineering bituminous road surfaces.

Description

A test device for simulating actual pavement cracking by reflecting cracks

technical field

The utility model belongs to the technical field of crack resistance research of highway engineering asphalt pavement, and relates to a test device for simulating actual pavement cracking by reflecting cracks.

Background technique

Reflective cracks mean that the base layer of the pavement generates cracks before the surface layer and reflects the cracks in the base layer to the surface layer. Under the combined action of temperature-humidity cycle stress and repeated load stress, base cracks and initial defects generate stress concentration at the bottom of the surface layer, which first leads to cracking at the bottom of the surface layer, and then gradually expands upward from the bottom of the surface layer, finally causing the crack to penetrate the entire surface layer , forming reflective cracks. Reflective cracks seriously damage the integrity and continuity of the pavement structure and weaken the strength of the pavement structure to a certain extent; and the immersion of rainwater or snow water will cause the base layer to soften, and the pavement strength will be greatly reduced under repeated driving loads. Reduced, resulting in scour and mud pumping phenomenon.

In recent years, the research on reflective cracks of asphalt pavement has been very active in the field of road engineering at home and abroad. However, most research methods analyze reflective cracks at the theoretical level, such as static force analysis, fracture mechanics, etc., which cannot completely solve the research topic of reflective cracks. Therefore, it is necessary to link theory with practice through indoor simulation experiments, control the main experimental factors in a relatively short period of time to conduct experimental analysis and research, and evaluate the crack resistance of asphalt pavements with different structures.

The indoor tests of reflective cracks on asphalt pavement can be mainly divided into the following categories:

(1) Direct tensile test

(2) Indirect tensile test

(3) Bending-tensile fatigue test

(4) Shear fatigue test

(5) Test plate fatigue test

Throughout the above experiments, they are mainly based on phenomenology or mechanical approximation. The phenomenological method analyzes the influence of asphalt on the anti-crack performance of the mixture, and does not involve the difference in the anti-crack performance of the entire pavement caused by the change of the pavement structure; the mechanical approximation method analyzes the crack propagation law of the asphalt mixture, but the calculation results are not consistent with the actual engineering conditions. Big difference. It can be seen that these indoor test methods cannot truly reflect the formation, expansion and fracture of pavement structure reflective cracks. Therefore, it is of great practical significance to develop a test device that can truly reflect the formation of reflective cracks in the asphalt pavement structure under load.

Utility model content

In order to solve the deficiencies in the prior art, the utility model provides a test device for simulating actual pavement cracking by reflecting cracks, through which the number of cycles required for cracks to penetrate the entire test piece and the number of asphalt mixtures under specific test conditions can be obtained. The crack propagation parameters provide a reliable test basis for the structural design of asphalt pavement.

Its technical solution is:

A test device for simulating actual pavement cracking by reflecting cracks, including a test machine 7, a measurement system 8, an environmental chamber 3, a data acquisition system 6, and an asphalt pavement simulation platform 9, a test machine 7, a measurement system 8, and an asphalt pavement simulation platform 9 are located in the environmental chamber 3, the testing machine 7 is connected to the asphalt pavement simulation platform 9 to load it, the measurement system 8 is connected to the asphalt simulation platform 9 to measure the deformation parameters in the test, and the measurement system 8 is externally connected to the data acquisition system 6 Used to collect test data.

Further preferably, the measurement system 3 includes a temperature sensor, a load cell, and a time deformation observer.

Further preferably, the asphalt pavement simulation platform 9 is composed of an aluminum plate 1 , a fixed steel plate 4 and a movable steel plate 5 .

Further preferably, grooves are distributed on the asphalt pavement simulation platform 9 .

Further preferably, the asphalt pavement simulation platform 9 is equivalent to the base layer of the road structure and may have an initial crack of 0-2 mm.

Further preferably, the size of the asphalt pavement simulation platform 9 is 300mm long, 150mm wide and 13mm high.

Further preferably, the asphalt pavement simulation platform 9 is made of steel plates.

The beneficial effects of the utility model:

(1) The experimental device of the utility model can realize the automatic observation of the service life of the reflection crack by analyzing the time axis of the load displacement.

(2) The environmental chamber of this experimental device is an optional part, and the indoor simulation test is diversified.

(3) The data acquisition system is controlled by a computer, which increases the convenience of the test operation.

(4) Connect theory with practice, control the main experimental factors in a short period of time to conduct experimental analysis and research, and evaluate the crack resistance of asphalt pavement with different structures.

(5) The experiment is easy to operate and the data accuracy is high. The asphalt pavement simulation platform plate is distributed with grooves at regular intervals and glued with the test piece, which can better simulate the actual state of the pavement.

Description of drawings

Fig. 1 is a schematic diagram of the test device;

Figure 2 is a plan view of the simulation platform;

Fig. 3 is the loading waveform diagram of this test device;

Figure 4 is a schematic diagram of the test piece fabrication process.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

Referring to Figures 1 and 2, a test device for simulating actual pavement cracking by reflecting cracks includes an environmental chamber 3, a data acquisition system 6, a testing machine 7, a measurement system 8, and an asphalt pavement simulation platform 9. Among them, the test piece 2, the test machine 7, the measurement system 8 and the asphalt pavement simulation platform 9 are all located in the environmental chamber 3, the test machine 7 is connected to the asphalt pavement simulation platform 9 for loading, and the measurement system 8 is connected to the asphalt simulation platform 9 Used to measure the deformation parameters in the test. The measurement system 8 is externally connected to the data acquisition system 6 for collecting test data.

The measurement system 3 includes a temperature sensor, a load cell, and a time deformation observer.

The asphalt pavement simulation platform 9 is composed of an aluminum plate 1 , a fixed steel plate 4 and a movable steel plate 5 .

Grooves are distributed on the asphalt pavement simulation platform 9, and the size of the asphalt pavement simulation platform 9 is 300 mm long, 150 mm wide, and 13 mm high, on which the test piece 10 is glued.

The asphalt pavement simulation platform 9 is made of high-strength steel plates.

The specimen 2 is glued to the aluminum plate 1, and the glued specimen should be solidified for 4 hours at a room temperature of 25°C, so that the glue has sufficient strength. The environmental chamber 3 and the measurement system 8 are calibrated before the test. This test is carried out at a specific temperature such as room temperature 25°C, the specimen itself has an open displacement of 0.63mm, and must have the same temperature as the environmental room. The simulated platform is equivalent to the base layer of the road structure and may have an initial crack of 0-2mm. The measurement system 8 can be used to conveniently determine when the test piece 2 reaches the required temperature, and the recommended temperature is room temperature 25°C. The aluminum plate 1 glued to the test piece is fixed with bolts.

Referring to Fig. 3, the utility model adopts a cyclic triangular waveform loading mode through the testing machine 7, and repeatedly loads the test piece at a loading rate of one cycle every 10 seconds until the loading fails. During the test, the movable steel plate 5 will have horizontal displacement relative to the fixed steel plate 4, and then the test piece 2 glued on the steel plate will be cracked, which is to simulate the reflective cracking process of the road surface. Then, the test data is measured, collected and recorded through the measurement system 8 and the data acquisition system 6, so as to prepare for later analysis and calculation.

The fabrication process of the test piece is shown in Figure 4:

Firstly, the original cylinder specimen with a diameter of 150mm and a height of 57mm is prepared, generally with a porosity of 7%, which can better simulate the site conditions. Then use a saw to roughly cut the test piece to a height of 38mm to obtain a cut test piece, and finally trim it to a height of 38mm from both sides, and finally obtain a test piece with a length of 150mm, a width of 76mm, and a height of 38mm.

The embodiments of the present utility model are not limited thereto, and simple transformations and equivalent replacements of the technical solutions thereof all fall within the protection scope of the present utility model.

Claims (7)

1. A test device for simulating actual pavement cracking by reflecting cracks, characterized in that it comprises a testing machine (7), a measurement system (8), an environmental chamber (3), a data acquisition system (6) and an asphalt pavement simulation platform (9), the testing machine (7), the measurement system (8) and the asphalt pavement simulation platform (9) are all located in the environmental chamber (3), the testing machine (7) is connected with the asphalt pavement simulation platform (9), and the measurement system (8) is connected with the asphalt simulation platform (9), and the measurement system (8) is externally connected with the data acquisition system (6). 2. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, wherein said measurement system (8) includes a temperature sensor, a load cell, and a time deformation observer. 3. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, wherein said asphalt pavement simulation platform (9) consists of aluminum plate (1), fixed steel plate (4) and movable steel plate (5) Composition. 4. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, characterized in that grooves are distributed on the asphalt pavement simulation platform (9). 5. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, characterized in that, the asphalt pavement simulation platform (9) is equivalent to the base layer of the road structure and can have an initial crack of 0-2mm. 6. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, characterized in that, the asphalt pavement simulation platform (9) size is 300mm long, 150mm wide, and 13mm high. 7. The test device for simulating actual pavement cracking by reflecting cracks according to claim 1, characterized in that, the asphalt pavement simulation platform (9) is made of a steel plate. the

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