This standard specifies the method for determining the indirect tensile strength of rock specimens, primarily through the Brazilian test. It covers the required apparatus, specimen dimensions and preparation, testing procedure, and the formula for calculation.
Method of test for the determination of tensile strength by indirect tests on rock specimens
Quick Reference Values
Minimum specimen diameter45 mm
Specimen length to diameter ratio (L/D)0.5
Recommended loading rate200 N/s
Minimum number of test specimens5
Permissible variation in specimen diameter0.2 mm
Key Formulas
σt = 2P / (πDL) — Tensile strength from Brazilian Test
Practical Notes
Ensure perfect diametral loading alignment to prevent shear failure and obtain valid tensile strength results.
The test is highly sensitive to specimen preparation; flat, parallel, and smooth loading surfaces are critical.
For a valid test, the fracture must initiate near the center of the specimen and propagate along the loaded diameter.