Compression Testing Machine for Concrete Test Specimens

A compression testing machine, electric or hydraulic, with a capacity above the failure load of the specimen and a spherically seated upper platen. For 10 × 20 cm cylinders up to 40 MPa, the force reaches about 314 kN; for 15 × 30 cm cylinders at 50 MPa, about 884 kN. The Biopdi electric compression testing machine ranges from 5 kN to 1,000 kN (224,809 lbf).

ABNT NBR 5739:2018 (the Brazilian standard) defines the compression test of cylindrical concrete specimens: continuous loading at 0.45 ± 0.15 MPa/s until failure and strength fc = 4F/(πD²). Molding and curing of the specimens follow ABNT NBR 5738 (the Brazilian standard for specimen preparation and curing).

It is the Biopdi M2 line universal testing machine (UTM) fitted with compression platens. The force comes from an electric motor that drives the crosshead through ball screws, with no oil or hydraulic pump, and the machine ranges from 5 kN to 1,000 kN (224,809 lbf). That is why it handles the compression tests used in civil construction and, by changing the fixture, also tensile tests of steel and flexural tests of prisms.

A hydraulic machine applies the force through an oil-filled cylinder and is dedicated to compression. An electric machine controls the crosshead speed with the motor and performs compression, tensile and flexural tests on the same frame, with the software calculating the result. For a lab that only breaks cylinders, both will do the job; for those who also test steel, prisms or blocks, the electric machine avoids a second piece of equipment. List your tests in the quote request and our team will recommend the right option.

The failure load is the strength times the area. A 10 × 20 cm cylinder at 40 MPa fails at about 314 kN, and a 15 × 30 cm cylinder at 40 MPa at about 707 kN. Choose a capacity above the highest expected force, as in the table on this page, and check on the calibration certificate that the verified range also covers the lower forces the lab will measure.

The standard requires continuous loading at 0.45 ± 0.15 MPa/s, a class 1 or better machine in the testing lab and a spherically seated upper platen. The BioLab software converts the rate in MPa/s to kN/s from the measured diameter, and the M2 line load cell is class 1 per ISO 7500-1 (ABNT NBR ISO 7500-1 in Brazil). The class of the assembled machine is determined by verification at the calibration laboratory. State the standard in your request so the proposal includes the compatible platens.

One tonne-force equals 9.807 kN, so 100 tf is about 981 kN. The largest model, the MBIOII-1000-M2, has a capacity of 1,000 kN (224,809 lbf), a little more than 100 tonnes-force.

Yes, because it is a universal testing machine. With grips, it performs the tensile test on steel bars per NBR 7480 (the Brazilian standard for steel reinforcing bars); with the flexural fixture, the flexural tensile test on prisms per NBR 12142; with bearing strips on the platens, the splitting tensile test (diametral compression) per NBR 7222. You change the accessory, not the machine.

At Biopdi, there is no difference in the equipment: the electric press is the universal testing machine configured for compression. The name changes with the application. In civil construction, where labs break cylinders and blocks, people usually say press; in metals and polymers, where labs run tensile tests, they usually say universal testing machine or tensile testing machine.

Yes. The class required by NBR 5739 is the class of the machine verified per ISO 7500-1 (ABNT NBR ISO 7500-1 in Brazil) by a calibration laboratory, and the certificate states the force range in which the class was achieved. The article on universal testing machine calibration explains the process and what to check in the certificate.