Measurement, control, thermographic and infrared instruments
The extraction methods consist in measuring the force required to extract the inserts from the concrete pre or post-inserted.
The extraction tests may be carried out:
- Bolts pre-entered in the jets (pull-out test), and this in order to check the resistance at various stages of maturation of the jet or in a monitoring program over time the quality of the concrete and the state of decay;
- With elements post-inserted (expansion screws geometric or forced expansion) for measuring the actual resistance of the concrete.
For the purposes of assessing the strength of the concrete on the basis of the results of the test pull-out, it is necessary from time to time to calibrate the method as the correlations essentially depend on the equipment used.
For tests carried out according to EN 12504-3, the results can be processed according to the prEN 13791, in a similar way to index data ultrasonic speed and concrete test hammer.