RU78944U1 - DEVICE FOR PREPARING ASPHALT CONCRETE AND CONCRETE PRODUCTS FOR DETERMINING THEIR STRENGTH AND DEFORMATIVE CHARACTERISTICS - Google Patents

Abstract

A device for preparing asphalt concrete and concrete products for determining their strength and deformation characteristics, containing a climate chamber equipped with a heating element and a humidifier, in which the test sample is located, characterized in that a strainer is placed inside the climate chamber, containing a rod installed with the possibility of vibration vertical movements under the action of an eccentric located above its upper part and a spring located between two brackets, The upper of which is rigidly connected to the rod and installed with the possibility of movement along vertical guides, and the lower one is fixed to the chamber wall and has a hole through which the rod passes freely, a roller equipped with a brake device is attached to the lower part of the rod, a test sample is attached under the roller, fixed on a trolley located on bearings mounted to move along the rails, while the climate chamber is additionally equipped with a refrigeration device.

Description

The proposed utility model relates to devices for testing road-building materials, namely, their preparation for determining the strength and deformation characteristics of asphalt concrete and concrete products and for their practical implementation, and can be used in the road economy, construction of airfields, and the construction industry.

Currently, in connection with an increase in the load on the roadbed and traffic intensity, the problem of increasing its durability is becoming urgent. To develop new materials and technologies for the construction and repair of roads, knowledge of the strength and deformation parameters of the components of pavement is necessary. Due to the lack of theoretical methods for their calculation, these parameters are determined experimentally - asphalt concrete test method. The use of inaccurate parameters of asphalt concrete in the calculations leads to incorrect results, as a result of which erroneous construction and overhaul periods are established. To obtain strength and deformation characteristics of asphalt concrete products, they are preliminarily subjected to various external influences and then they are destroyed.

A device is known for testing asphalt concrete for shear stability, comprising a drive shaft on which the test sample is mounted, a roller mounted on the driven shaft, a bed and a sample rotation drive (see RU No. 2086950, G01N 3/24, publ. 10.08.1997). .

However, the known device is intended for testing samples.

cylindrical to shear strain and at a certain positive temperature and without the presence of free water in the pores of the sample, while the road surface experiences various types of deformations and additional stresses due to freezing of free water filling the pores of asphalt concrete. Therefore, the known device for testing a sample does not create real operating conditions for asphalt concrete pavement.

Closest to the claimed utility model in technical essence is a device for testing the stability of asphalt concrete, including a climatic chamber equipped with a heating element and a humidifier, in which the test sample is located (see RU No. 2025712, G01N 17/00, publ. 30.12.1994).

The disadvantages of the known device is that in the climatic chamber, the samples are subjected to a positive temperature effect, and the road surfaces are also operated at low temperatures, and when free water freezes in the pore space of asphalt concrete, additional stresses arise in them, which are not taken into account in the prototype. Testing of the samples is carried out by creating compression deformations in them, whereas under actual operating conditions of the road, the road surface experiences compression, shear and bending deformations at the same time. And therefore, the characteristics determined after sample preparation in the climate chamber are inaccurate, far from operational, which ultimately distorts the information on the operational resource of asphalt concrete and concrete products.

The claimed utility model is aimed at solving a technical problem, which consists in determining the strength and deformation characteristics of asphalt concrete and concrete products after their preparation in conditions as close to operational as possible.

The technical result of the utility model is the creation in the test samples of various types of deformations in real climatic conditions in a wide range of temperatures and humidity, obtaining more reliable strength and deformation characteristics of the samples to obtain information about the service life of asphalt concrete and concrete products.

The specified technical result is achieved by the fact that in the device for preparing asphalt concrete and concrete products for determining their strength and deformation characteristics, containing a climate chamber equipped with a heating element and a humidifier in which the test sample is located, according to a utility model, a device for deformation is placed inside the climate chamber, containing a rod installed with the possibility of oscillatory movement vertically under the action located above its upper part eks a spring and a spring located between two brackets, the upper of which is rigidly connected to the rod and mounted with the possibility of movement along vertical guides, and the lower one is fixed to the chamber wall and has a hole through which the rod freely passes, a roller equipped with brake device, under the roller is a test sample mounted on a trolley located on bearings mounted to move along the rails, while the climate chamber is additionally sleep wife of the refrigerating device.

Distinctive features of the claimed device are the presence of new structural elements, namely the introduction of a device for deformation into the climate chamber, supplying it with a refrigeration device. A device for deformations provides for the creation of various types of deformations in a sample placed in a climate chamber, and a refrigeration device together with a heating element and a humidifier

allows you to create real climatic conditions in a wide range of temperatures and humidity.

The proposed utility model is illustrated by drawings, in which Fig. 1 schematically shows a device for preparing asphalt concrete and concrete products for determining their strength and deformation characteristics, Fig. 2 is a conditional diagram of the action of a wheel on a road surface, a front view, and Fig. 3 is a conditional scheme of the action of the wheel on the road surface, side view.

The inventive device (see Fig. 1) contains a climatic chamber 1, inside of which there is a device for deformations containing a rod 2, in the lower part of which a roller 3 is mounted, equipped with a brake device (not shown in Fig.). The rod 2 is mounted with the possibility of oscillating movement vertically under the action of the eccentric 4 located above its upper part and the spring 5. The spring 5 is located between two brackets 6 and 7. The upper bracket 6 is rigidly connected to the rod 2 and is mounted with the possibility of movement along vertical guides 8, mounted on the wall of the chamber 1. The bottom 7 bracket is rigidly fixed to the wall of the chamber 1 and has a hole 9 through which the rod 2 freely passes. Under the roller 3 is a test sample 10 mounted on a trolley 11, located constant on bearings 12 mounted for movement along the guides 13. Climate chamber 1 is provided with a heating element 14, the refrigerating device 15, the humidifier 16.

The inventive device for the preparation of asphalt concrete and concrete products for determining their strength and deformation characteristics is as follows.

The test sample 10 is placed in a climatic chamber 1 and mounted on a trolley 11 (figure 1). Then, using a humidifier 16, a heating element 14, or a refrigeration device 15, a predetermined temperature is created in the climate chamber in the range from (+70) ° C to

(-70) ° С and humidity. After reaching a constant value of temperature and humidity, an electric drive (not shown in FIG. 1) is turned on, leading the trolley 11 mounted on bearings 12 to the reciprocating movement along the guides 13. At the same time, an electric drive (not shown in FIG. 1) is turned on ), which causes the eccentric 4 to rotate. Under the action of the eccentric 4, the rod 2 moves down and presses the roller 3 against the moving sample 10 with a given force. In this case, the spring 5 is compressed under the action of the bracket 6 and abuts against the fixed bracket 7. When the spring 5 is unclenched, the rod 2 returns to the upper position behind the eccentric 4. Thus, the rod 2 with the roller 3 oscillates vertically. Under the action of the rotating roller 3 and the forces of pressing it against the sample 10, the latter experiences various types of deformations: in region A, bending strain and in region B, compressive deformation (see Fig. 2). When you turn on the braking device of the roller 3, simulating the movement of vehicles with acceleration, the upper layers of the sample 10 under the action of a non-rotating roller 3 are shifted relative to the lower ones, the sample 10 experiences a shear deformation in region B (see Fig. 3).

The values of temperature and humidity of the sample, as well as the pressure of the roller against the sample, the speed of the trolley 11, the speed of the eccentric 4 are determined from the actual conditions of movement of vehicles on the road surface.

After preparing the test sample by conducting deformations at a certain temperature and humidity for a specified time, its strength and deformation characteristics are determined, the results of which yield the corresponding conclusions.

Claims (1)

A device for preparing asphalt concrete and concrete products for determining their strength and deformation characteristics, containing a climate chamber equipped with a heating element and a humidifier, in which the test sample is located, characterized in that a strainer is placed inside the climate chamber, containing a rod installed with the possibility of vibration vertical movements under the action of an eccentric located above its upper part and a spring located between two brackets, The upper of which is rigidly connected to the rod and installed with the possibility of movement along vertical guides, and the lower one is fixed to the chamber wall and has a hole through which the rod passes freely, a roller equipped with a brake device is attached to the lower part of the rod, a test sample is attached under the roller, fixed on a trolley located on bearings mounted to move along the rails, while the climate chamber is additionally equipped with a refrigeration device.