A device for measuring the strength of concrete - the main

Concrete is one of the most common types of structures, the durability and reliability of the entire object as a whole depends on its quality and strength. It is not surprising that the determination of the strength properties is a very important task in the process of building an object and putting it into operation. For this purpose, various methods and types of equipment are used, and we will consider them as part of this review.

Basic methods for testing concrete

It should be noted that the equipment of this group can be used to test the strength of both concrete and brick. Strength is understood as the ability of a material to resist destruction under the action of internal stress and various external factors. The higher the resistance, the more reliable and durable the design.

You can check through two ways:

• Destructive: the essence of this method is that previously prepared blanks are crushed in a special press. These can be cubes, which are cast from controlled concrete or cores — fragments of a cylindrical shape, which diamond drilling of holes in concrete and removal of a fragment helps to obtain.

• The second option is to use a device to determine the strength of concrete by non-destructive method.. Such equipment measures physical quantities that have a direct impact on the strength of concrete, and recalculates them, giving the desired performance. Naturally, the better the equipment, the smaller the error and the higher the accuracy of research.

Types of devices

When carrying out measuring activities, one of the two main types of measuring equipment is most often used. Naturally, doing your own hands means exactly this option, since the price of a special press is very high, and there is no point in keeping it if you do not have a special testing laboratory for providing strength measurement services and other indicators.

Determination of mechanical strength

If a non-destructive testing (NC) is carried out mechanically, the main regulatory act that should be followed is GOST 22690-88 “Concretes. Determination of strength by mechanical methods NK. This document sets out the rules for testing both heavy and light concrete with ultimate strength values ​​that do not go beyond the range from 5 to 100 MPa.

This group of devices includes several basic types of equipment, which differs in the method of determining those or other indirect characteristics.

These may be the following indicators:

• Energy impact special brisk.
• The value of the rebound of the striker from the drummer pressed to the wall.
• The size of the left trail of impact.
• Indicator of the force required to destroy a small area on the edges of the structure or when a fixed anchor bolt is pulled out.

Features of measurement using one method or another depend on many factors, therefore, the instruction manual of the device is required to study. Consider the most popular variant of the test - the method of elastic rebound.

The technology is as follows:

• The measuring unit should be perpendicular to the surface; the greater the skew, the greater the measurement error, you should not forget about it.

• The test should be carried out on different parts of the surface, for correct measurements, you should have at least 5 values ​​and determine the arithmetic average.
• With the help of a special formula, the strength index of a particular structure is calculated. In fact, everything is quite simple and, following the recommendations and requirements of the instructions, it is possible to carry out qualitative measurements, even without proper practice.

Note! To ensure that the figures were accurate and correct, you should not forget that the minimum thickness of the concrete structure should not be less than 100 mm.

Using the ultrasound method

When using this method of calculating the strength of a concrete or a brick, all requirements for measurements and the order of their performance are determined by GOST 17624-87 “Concretes. Ultrasonic method for determining the strength. It should be noted that with the help of this method it is possible to measure almost all types of concrete, this makes this option as versatile as possible.

With the help of ultrasound, one can measure both the indicators of the finished structures and the material that has not yet gained optimum strength indicators. That is, you can track the process of hardening of the material.

Features of this type of measurement are as follows:

• The method itself is based on the physical relationship between the value of concrete strength and the speed of propagation of sound vibrations through it. This relationship can be expressed in the form of a formula, graph or table, experts call it "calibration characteristic". This indicator is determined separately for each object of measurement; in the verification process, surface or through sounding is used.
• According to the results of verification and selection of calibration characteristics, the main test activities are carried out, and they should be carried out in the same way as the verification ones.
• On the basis of the obtained indicators, the actual strength of a particular section of the concrete structure is determined.

Note! The more accurately the calibration characteristic is determined, the higher the accuracy of the final results will be.

Testing may be needed in a variety of cases: from determining the reliability of a structure to calculating the dynamics of hardening of a concrete material. If reinforced concrete is to be cut with diamond circles, it is also advisable to measure the strength and select the optimum type of wheel for the concrete.

Conclusion

In some cases, very much depends on the accuracy of the measurements, especially when it comes to repairs and measures to strengthen the structure. Only correct data guarantees that the necessary option of the further actions will be chosen. The video in this article will help to understand some of the features of the use of measuring devices.