How To Execute The Flexural Strength Test of Concrete?

flexural testing machine

A flexural strength test is a test performed to indirectly assess the tensile strength of the concrete. It checks out if the concrete beam or the slab can bear failure of bending. Whatever results of the test come, they are presented as a modulus rupture in Mpa psi.

Flexural Strength

Flexural strength is also called bend strength, fracture strength, or modulus of rupture. It is a parameter used for the brittle material in which the capacity of the material to resist the deformation created by the load is tested.

The highest amount of stress borne within the material at the time of the rupture is represented by the flexural strength.

Flexural testing machine

The flexural testing machine for the concrete has two steel rollers, and each of these two rollers has a diameter of 38 mm. The bed should give the required support to the specimen at the time when the rollers stay mounted so that the distance between the two centres remains 60 cm for 15 cm specimen of 40 cm for 10 cm. furthermore, the load between the two rollers should be distributed proportionately. In addition to this, make sure that all the rollers are arranged in such a manner that the load is exerted without putting strain on the specimen.


The following is the procedure that should be undertaken to perform the test.

Step 1– First, to prepare the test sample, fill the concrete in 3 layers of like thickness. Next, tamp the layers with the help of the tamping approximately 35 times. It is important to disburse the tamping in equal proportion across the beam’s cross-section and within each layer.

Step 2– In this step, the surface of the bearing loading and the assisting rollers are cleaned. Make sure that all the loose sand or other material is removed from the surface area where they could come in direct contact with the rollers if not get ridden off.

Step 3– Here, in this step, the circular rollers are utilized to offer support and load points to the specimen. As compared to the test samples’ width, the rollers need to be at least 10 mm more. One should note that all the four rollers are used, in which 3 should be used to twist within their axes.

Step 4– Once the water is removed from the sample, the sample should be immediately tested. The specimen should be kept properly in the machine by ensuring that the longitudinal axis faces right to that of rollers.

Safety measures required 

The following are the safety measures that need to be taken care of:

  • AT the time of performing the test, hand gloves and safety shoes must be worn.
  • After the test is performed, switch off the machine.
  • It is important to mold grease the internal tools.
  • The guide rods should be placed in a fixed position.
  • It is recommended to clean the pieces of equipment before and after the testing.

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