Device for controlled vibration of concrete mixtures during rheotesting

Abstract

This utility model relates to construction technologies, specifically to devices for rheological testing of concrete mixtures, and can be used to evaluate the rheological properties of concrete mixtures by creating controlled vibration effects through a contact plate. The device can be used in construction materials laboratories for rheological testing; in research centers for studying the properties of concrete mixtures; and in precast concrete plants for quality control of raw materials and finished mixtures. The technical result: increased accuracy in monitoring vibration parameters (amplitude, frequency, waveform).

Description

[0001] The utility model relates to construction technologies, in particular to devices for rheological testing of concrete mixtures, and can be used to evaluate the rheological properties of concrete mixtures by creating controlled vibration effects through a contact plate.

[0002] The device can be used in:

[0003] building materials laboratories for rheological testing;

[0004] research centers for studying the properties of concrete mixtures;

[0005] at reinforced concrete enterprises to control the quality of raw materials and finished mixtures.

[0006] Known devices for vibrating concrete mixtures (electromechanical vibrators, pneumatic systems) transmit vibration either to a container with a sample or directly to the mixture through immersion elements.

[0007] This results in:

[0008] uneven distribution of vibration in the volume of the mixture;

[0009] distortion of rheotest results due to parasitic fluctuations in capacitance;

[0010] Difficulties in controlling the impact parameters at the mixture-container boundary.

[0011] Patent RU 2782675 C1 "Device for Determining the Rheological Properties of Concrete Mixture." The invention relates to measuring the rheological properties of heavy and fine-grained concrete mixtures, cement-sand mortars, and monitoring their technical condition during the initial stage of hardening. The device comprises a handle with a rod, an elongated impact hammer, a conical rod indenter, and a mandrel.

[0012] Patent RU 2716285 C1 "Device for Measuring the Viscosity of Concrete Mixture." The device includes a metal base, an L-shaped stand, two roller units, an elastic thread with a magnet and counterweight, a lead ball, a removable cylinder with a rubber insert, and a vibrating plate with a vibrator.

[0013] The devices do not allow for precise setting and control of vibration parameters during retesting of concrete mixtures.

[0014] The objective of the utility model is to create a device for precise and controlled vibration of concrete mixtures during rheotesting, where vibration is transmitted directly to the mixture through a plate, eliminating the influence of container fluctuations.

[0015] Technical result

[0016] Improving the accuracy of vibration parameter control (amplitude, frequency, waveform).

[0017] The technical result is achieved due to:

[0018] using a moving coil linear actuator to generate vibration;

[0019] transmission of vibration to the concrete mixture through a rigid plate in contact with the surface of the sample;

[0020] Minimizing parasitic oscillations by rigidly fixing the capacitor and isolating the actuator.

[0021] Device design (Fig. 1).

[0022] The device contains:

[0023] 1. Linear actuator with moving coil in constant magnetic field.

[0024] Device parameters:

[0025] Vibration frequency range: 1-200Hz;

[0026] Plate vibration amplitude: 0.1-5mm;

[0027] Maximum force on plate: 50N;

[0028] frequency maintaining accuracy: ±0.5Hz;

[0029] Amplitude maintaining accuracy: ±0.01mm.

[0030] 2. Vibration plate - a rigid element made of stainless steel or aluminum alloy, mounted on the rod of a linear actuator with a moving coil. The plate has a flat contact surface that contacts the concrete mixture (thickness 3 mm, contact area 50x50 mm, or other depending on the sample size).

[0031] 3. A fixed container for the concrete mix sample, mounted on a vibration-isolating base. The container is rigidly fixed and does not participate in vibration.

[0032] 4. Control unit - microprocessor controller with digital-to-analog converter (DAC) for generating a control signal.

[0033] 5. Feedback sensors:

[0034] 5.1 Accelerometer fixed on the plate to measure vibration acceleration;

[0035] 5.2. Force sensor located between the actuator rod and the plate to monitor the impact force.

[0036] 6. Housing with vibration-isolating elements, preventing the transmission of vibrations to the environment.

[0037] All units are connected to each other by welding and bolting.

[0038] Working principle

[0039] 1. The concrete mix sample is placed in a fixed container.

[0040] 2. The vibrating plate descends until it contacts the mixture surface without initial force.

[0041] 3. The control unit generates a control signal of a given frequency and amplitude, which is fed to the coil of the linear actuator.

[0042] 4. The force drives the rod with the plate, creating vibration that is transmitted to the surface of the concrete mixture.

[0043] 5. Feedback sensors transmit data to the control unit, which adjusts the control signal to maintain the specified vibration parameters.

[0044] 6. The rheometer records the rheological properties of the mixture under the influence of vibration transmitted through the plate.

[0045] Advantages of the utility model:

[0046] vibration is transmitted directly to the concrete mixture, bypassing the container, which eliminates parasitic vibrations;

[0047] uniform distribution of vibration over the surface of the sample;

[0048] high precision control of vibration parameters (frequency and amplitude);

[0049] wide range of frequencies and amplitudes;

[0050] the ability to automate the testing process;

[0051] compatible with various types of rheometers.

Claims

1. A device for controlled vibration of concrete mixtures during rheotesting, characterized in that it contains a housing equipped with vibration-isolating elements, a control unit, a container for samples mounted on a vibration-isolating base, a linear actuator with a moving coil, wherein a vibration plate is fixed to the actuator rod, which contacts the surface of the sample and has a flat contact surface, wherein the control unit corrects the vibration parameters based on data from feedback sensors, an accelerometer fixed to the plate, and a force sensor fixed between the rod of the linear actuator and the vibration plate, 2. The device according to paragraph 1, characterized in that the vibration frequency range is 1-200 Hz, the amplitude is 0.1-5 mm, and the maximum force is 50 N.

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