Split Tensile Strength

Split tensile strength is the tensile strength of concrete measured indirectly by the cylinder splitting (Brazilian) test per IS 5816: a standard 150 × 300 mm cylinder is loaded in compression along two diametrically opposite lines until it splits, and the tensile strength is computed as fct = 2P/(πLD). Concrete is weak in direct tension (only about 8–12% of its compressive strength), and a true uniaxial tension test is impractical, so the splitting test (and the flexural modulus-of-rupture test) are the standard ways to characterise tensile behaviour.

The value matters wherever cracking, not crushing, governs — pavement slabs, water-retaining structures, shear and diagonal-tension behaviour, and shrinkage/temperature crack control. IS 456 Cl. 6.2.2 gives the design flexural tensile strength as fcr = 0.7√fck (MPa); the split value is typically a little lower than the flexural value for the same concrete. It is a routine acceptance test for pavement-quality concrete and a useful cross-check on mix tensile performance.