Markets that sell compression testing machine offer a wide range of machines and it comes as no surprise that customers are spoilt for a choice! For some, choosing a compression frame is complex because concrete is technical material-wise and the pursuit for ever-increasing strength continues. In essence, the proficiency of concrete mechanical characteristics is an issue in today’s modern world. The testing machine is the main assessment element for mechanical resistance. It defines itself by many criteria, of which the main are:
Operating
Most machines are hydraulic and they operate either by pressure control or by flow control. Both technologies are equivalent for testing rigid materials, but the latter one is simpler and more stable over time.
The digital display of TSY compression testing machine
Maximum force
Obviously, your testing has to vary in that, it’s better not to regularly use the machine at above 80% of its maximum force capacity.
Maximum pressure
The higher the pressure, the smaller the bore of the hydraulic jack will be. Therefore, frame dimensions are reduced resulting in reduced material and weight. On the other hand, the higher the pressure is, the more the oil is compressed and stores energy. This energy will be restricted during the rupture of the specimen. In doing so, the electric motor is more stressed, causing excessive heating and lamination of the hydraulic oil, reducing performance over time.
Weight
Weight is not a decision factor, per se, because it depends on the conception of the machine but it gives a good idea about its robustness and its durability. As a rule, the heavier the frame, less it will distort, and the better it will run over time.
Rigidity
Axial rigidity is the maximum force of the machine divided by deformation at this load. It’s expressed in kn/mm and is normally inferior to 1 for good machines. A very rigid machine is a guarantee of durability. If deformation under load is high, the energy restricted during fragile rupture on highly breakable materials (bricks, high performances concretes …) will result in the premature ageing of some pieces such as the ball joints, the plates and the jack. Transverse rigidity is seldom given and yet it is very important in order to ensure pertinent results. The standard NF EN 12390-4 stipulates alignment controls under load and the value of the transverse rigidity is decisive to meeting its requirements.
