What is the principle of rebar scanners？

The rebar scanners are mainly used for the detection of the steel bar distribution, diameter, direction, and the thickness and quality of the concrete cover in the concrete structure of the engineering building. The rebar scanners can measure the position of the steel bar on the surface of the concrete, the condition of the reinforcement, measure the thickness of the concrete cover, the diameter of the steel bar, etc. In addition, the rebar scanners can also detect the position of magnetic and electrical conductors in concrete structures, such as cables and plumbing pipes in walls, etc. Detection before construction can effectively avoid damage to these facilities during construction, to reduce accidents. The Rebar locator on reinforced concrete is an effective tool for construction process monitoring and quality inspection. 

How does LR-G200 Integrated Rebar Scanner equipment Work？

The rebar cover meter is composed of five major parts: host system, signal transmission system, signal acquisition system, probe, and man-machine interface. Under the control of the host computer, the signal transmission system generates an excitation signal of a certain frequency to excite the probe, and the probe senses the steel bar to be tested. The output signal is converted into a digital signal by the signal acquisition system and sent to the host computer system for processing to determine the position and protective layer of the steel bar. thickness and diameter of the bar.

Significance of rebar scanning

After the steel bar is corroded, the volume of the rust expands, causing the concrete protective layer to crack, and moisture or water seeps in, which accelerates and aggravates the corrosion of the steel bar, making the steel bar rust short and leads to building damage. Ensure that the thickness of the protective layer is within the range specified by the design and specifications, which can protect the steel bars from corrosion to the greatest extent, delay the time for the carbonation depth of the concrete to reach the surface of the steel bars, and ensure the service life of the structure. For buildings in some special environments, such as building structures in corrosive gas environments, some special regulations should be made on the steel reinforcement protective layer of concrete structures in the design to ensure the durability of the building structures.

Instrument Operation of the rebar cover meter

1) Instrument connection: Connect the host and probe with a signal cable, and tighten the plug fixing screw. Every time the probe is replaced, it should be connected well before starting up, so that the instrument can judge the probe. Please hold the root plug!

2) Power on and preset: Press the [ON/OFF] key to power on the instrument and automatically enter the options menu. Then preset the bar diameter.

3) Zero reset: pick up the probe and put it in the air, leave it at least 30cm away from the surface of concrete components and metal objects, and check whether the steel detector deviates from the zero point state when zeroing.

4) Measurement of steel bar position and protective layer thickness: place the probe parallel to the steel bar on the concrete surface at the starting position of the measurement area, and move the probe along the direction perpendicular to the steel bar on the concrete surface. During the movement, the indicator bar increases and the protective layer thickness value decreases. It means that the probe is moving towards the steel bar. When the axis of the steel bar coincides with the center line of the probe, the indicator bar is the longest and the thickness of the protective layer is the smallest. Read the detection value of the thickness of the concrete protective layer for the first detection. At the same position of the steel bar under test, it should Repeat the test once, and read the second test value of the concrete cover thickness. At the same time, mark the axis position of the reinforcement. After testing the steel bar cover thickness in the survey area, measure the distance between the marked adjacent steel bars in sequence.

rebar cover meter Considerations

①During the operation, the instrument should be handled with care, and tested in strict accordance with the instrument's operating procedures.

②During the testing process, steel bar joints should be avoided. If the difference between the thickness of the two concrete cover layers read at the same place is greater than 1mm, the test data of this group is invalid. If the requirements are still not met, the steel bar detector should be replaced or verified by drilling and chiseling.

③In the detection process, the method of adding pads under the probe can be used for detection.

④The moving speed of the probe shall not be greater than 2cm/s, try to keep moving at a constant speed, and avoid moving in the opposite direction before finding the steel bar, otherwise it will cause large detection errors or even missing bars.

⑤ If the continuous working time is long, in order to improve the detection accuracy, it should be noted that the probe should be taken into the air every 5 minutes, away from the metal, and press the confirmation button to reset. If you disagree with the test results, you can also do this.

⑥ Correctly set the steel bar diameter, otherwise, it will affect the test results.