This standard (Part 1) covers the procedures for destructive testing of hardened concrete to determine compressive, flexural, and splitting tensile strengths. It is used universally by QA/QC and site engineers to verify that concrete batches meet the design mix strength criteria.
Specifies methods for conducting destructive tests to determine the compressive, flexural, and split tensile strength of hardened concrete samples.
Quick Reference Values
Standard cube size150 mm x 150 mm x 150 mm
Alternate cube size (for aggregate < 20mm)100 mm x 100 mm x 100 mm
Standard cylinder size150 mm diameter x 300 mm height
Standard beam size (aggregate < 38mm)150 mm x 150 mm x 700 mm
Loading rate for compressive strength14 N/mm²/min
Curing water temperature27 ± 2 °C
Relative humidity for moist curing≥ 90%
Key Formulas
Compressive Strength = P / A (Where P is maximum load, A is cross-sectional area)
Flexural Strength (Modulus of Rupture) = (P × l) / (b × d²) [when fracture occurs in middle third]
Splitting Tensile Strength = (2 × P) / (π × L × d)
Practical Notes
Specimens must be tested immediately after removal from the curing water tank while they are still in a surface-wet (damp) condition.
During compressive testing, the load must be applied to the smooth sides of the cube (perpendicular to the direction of casting), never on the top or bottom trowelled surfaces.
Applying the load faster than the specified rate of 14 N/mm²/min will result in artificially high strength readings, while loading too slowly yields lower results.