Cement mortar compressive strength

Calculate strengths from three mortar cubes tested at the same curing age and measured loaded-face dimensions.

Observations and units

• Maximum failure load (kN)
• Mean loaded-face width (mm)
• Mean loaded-face depth (mm)

Calculation

Loaded area = mean width × mean depth; strength = 1000 × load (kN) / area (mm²).

Method reference and limitations

IS 4031 (Part 6):1988, clauses 7–8. Test three cubes from the same sample and curing age; record any manifestly faulty specimens. A deviation exceeding 10% of the initial sound-specimen mean excludes that strength, with the reason recorded. Rounded reporting values use 0.5 N/mm² increments; exact arithmetic remains visible. Faulty-specimen flags and a single >10% deviation screen determine retained specimens; fewer than two requires a retest. Masonry cement, grade acceptance and curing verification are excluded.

Calculation and reporting rules audited within the documented profile; physical test execution and specification acceptance remain the operator’s responsibility. Independent qualified review is not recorded. No certificate or compliance decision.

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