What is the Rebar Scanner?

Rebar scanner, mainly used for engineering construction concrete structure in the distribution of reinforcing bars, diameter, direction, the quality of the protective layer of concrete thickness inspection. Reinforcement scanner can determine the location of rebar on the surface of the concrete, the distribution of rebar, measure the thickness of the protective layer of concrete, the diameter of the rebar and so on. In addition, the rebar scanner can also detect the location of magnetic and conductive bodies in the concrete structure, such as cables and plumbing pipes inside the wall, etc. Pre-construction detection can effectively avoid damage to these facilities during construction and reduce the occurrence of accidents.

Rebar scanner is an effective tool for construction process monitoring and quality inspection. So, what is the principle of rebar scanner? Let us understand in detail.

Working principle of rebar scanner

The rebar scanner consists of a host system, signal transmission system, signal acquisition system, probe and human-machine interface and other five major components. Signal transmitter system under the control of the host, produce a certain frequency of excitation signal excitation probe, the probe senses the measured rebar, the output signal by the signal acquisition system is converted into a digital signal, sent to the host system for processing, determine the location of the rebar and the thickness of the protective layer and the diameter of the rebar.

Why do we need to carry out rebar testing

After the corrosion of rebar, rust volume expansion, resulting in cracking of the protective layer of concrete, moisture or water infiltration, accelerate and aggravate the corrosion of rebar, so that the rebar rust short, leading to the destruction of the building. Ensure that the thickness of the protective layer is within the scope of the design and specification, which can maximise the protection of reinforcement from corrosion and delay the depth of carbonation of concrete to the surface of the reinforcement time, to ensure that the structure of the service life. For some buildings in special environments, such as corrosive gases in the environment of the building structure, the design of the concrete structure of the protective layer of reinforcing steel but also to make some special provisions to ensure the durability of the building structure.

Instrument operation of rebar scanner

1. Instrument connection: connect the host and probe with signal cable, and tighten the plug fixing screws. Each time you change the probe should be connected before switching on, so that the instrument can determine the probe. Please hold the root to plug and unplug!
2. Switch on and preset: Press [On/Off] key, the instrument is switched on and automatically enters the option menu. Then preset the rebar diameter.
3. Zeroing: Pick up the probe and put it in the air, leave the surface of concrete members and metal objects at least 30cm, check whether the rebar detector deviates from the zero state when zeroing.
4. Determination of the location of the rebar and the protective layer thickness: the probe is parallel to the rebar, placed on the concrete surface of the starting position of the measurement area, along the concrete surface perpendicular to the direction of the rebar to move the probe, move the process, the indicator bar grows, the protective layer thickness value decreases, indicating that the probe is moving to the location of the reinforcing steel, when the reinforcing steel axis and the probe centerline coincides with the indicator bar is the longest, the protective layer thickness is the smallest, read the 1st detection of the Concrete protective layer thickness detection value, in the same position of the tested rebar should be repeated 1 time, read the 2nd concrete protective layer thickness detection value. At the same time, the axial position of the rebar is marked out. After testing the protective layer thickness of rebar in the test area, measure the spacing of the neighbouring rebars that have been marked.

Cautions

The instrument should be held lightly during the operation, and the test should be carried out in strict accordance with the instrument's operating procedures.

1. The detection process should avoid the reinforcement joints tied wire, the same place to read the two concrete protective layer thickness test value difference is greater than 1mm, the group of test data is invalid, and find out the reasons for the re-inspection in the place. Still does not meet the requirements, should be replaced with a rebar detector or the use of drilling, chiselling method of verification.
2. The detection process can use the method of additional pads under the probe for detection.
3. The moving speed of the probe shall not be greater than 2cm/s, try to keep moving at a constant speed, avoid moving in the opposite direction before finding the rebar, otherwise it will cause large detection error or even leakage.
4. If the continuous working time is long, in order to improve the detection accuracy, it should be noted that the probe should be taken to the air every 5 minutes, away from the metal, and reset by pressing the confirmation button. If you have any objection to the detection result, you can also do this operation.
5. Set the rebar diameter correctly, otherwise it will affect the detection result.

For more information on rebar scanners go to ATO.com.