This standard details the exact laboratory procedures for determining the compressive, flexural, and split tensile strengths of hardened concrete. Quality control engineers and material testing laboratories use it to verify that cast concrete meets the characteristic strength required by structural design.
Specifies procedures for determining compressive, flexural, and split tensile strength of concrete specimens.
Quick Reference Values
standard cube size150 x 150 x 150 mm
alternate cube size agg under 20mm100 x 100 x 100 mm
standard beam size flexure150 x 150 x 700 mm
standard cylinder size split tensile150 mm diameter x 300 mm length
loading rate compressive14 N/mm²/min
curing temperature27 ± 2 °C
curing humidityMinimum 90% or submerged in water
Key Formulas
fcf = (P × l) / (b × d²) — Flexural strength (if fracture occurs within middle third of span)
fct = 2P / (π × l × d) — Split tensile strength of cylinder
Practical Notes
The rate of loading must be strictly controlled at 14 N/mm²/min during compression tests; applying load too quickly will result in a falsely high strength reading.
For the split tensile test, placing plywood packing strips between the cylinder and the steel platens is mandatory to distribute the load and prevent premature local crushing.
Specimens must be tested immediately after removal from the curing water and wiped surface-dry; testing dry concrete cubes will yield 10-15% higher compressive strength values than saturated ones.