STRAIN GAUGE CYLINDERS

The resistance of hardened concrete to a compressive force is very important in the context of the safety of structures made from this material.

As in the case of steel and other materials, these concretes are also subject to mechanical qualification tests and their study involves testing concrete compression test specimens made on specific machines. To ensure the relevance of the results obtained, it is important that the compression machines are checked. This verification is done through EN 12390-4 (which corresponds to ASTM 74).

A very important parameter in the testing of concrete compression test specimens is the uniform application of force on the specimen section. In order to verify the homogeneity of the repartition of the forces generated, the standard defines a strain gauge transducer – called a strain gauge cylinder – as well as the tests to be carried out with it and the associated criteria.

SENSY has developed a cylinder which meets the definition of the standard and is designed for checking concrete compression testing machines.

Thus, SENSY is able to provide a strain gauge cylinder (reference 3115F) as well as take care of its calibration through a recognised test laboratory in order to fully meet the needs of checking the homogeneity of the repartition of the forces generated, as defined in EN12390-4.

SENSY also equips load cell based on this standard but capable of being used as standard reference force transducers, according to ISO 376.

In this case, it is a question of mixing both approaches, by combining the measurements of the different gauge bridges with a control of the repeatability and the hysteresis of the material to enable the force calibration of testing machines between trays.

Here, in addition to the sensor standardised according to the dimensions mentioned in EN12390-4 (2MN), SENSY manufactures sensors of larger dimensions for capacities of 3MN and 5MN capable of reaching class 1 or even 0,5 according to ISO 376.

In addition to the 3115F sensor, SENSY offers the INDI-12390, an electronic device with four independent indicators which, in accordance with EN12390, allows the uniformity of the application of the force to be verified by the test bench contact surfaces.

Each display is equipped with a peak memory to record measurements even after loading.

This electronics can be optionally equipped with RS-232 or RS-485 digital outputs.