Brazilian Test Curved Platens Indirect Tensile Brazil Test Test Jig

The Brazilian test is a simple indirect testing method to obtain the tensile strength of brittle material such as concrete, rock, and rock-like materials. In this test, a thin circular disc is diametrically compressed to failure.

The compression induces tensile stresses normal to the vertical diameter, which are essentially constant over a region around the centre. The indirect tensile strength is typically calculated based on the assumption that failure occurs at the point of maximum tensile stress, i.e., at the centre of the disc.

The suggested formula for calculating the splitting tensile strength σt(MPa) based on the Brazilian test is (ASTM 2008; ISRM 1978)

Where P is the load at failure (N), D is the diameter of the test specimen (mm), and t is the thickness of the test specimen measured at the centre (mm).

Description

In the Brazilian test, a disc shape specimen of the rock is loaded by two opposing normal strip loads at the disc periphery. The specimen diameter shall preferably be not less than NX core size (54 mm), or at least 10 times the average grain size. The thickness/diameter ratio should be 0.5 to 0.6. The load is continuously increased at a constant rate until failure of the sample occurs within few minutes. The loading rate depending on the material and may from 10 to 50 kN/min.