Consider the following strengths of concrete:
i. Cube strength
ii. Cylinder strength
iii. Split-tensile strength
iv. Modulus of rupture

The correct sequence in increasing order of these strengths is

Explanation:

Split-Tensile Strength

• Measures the indirect tensile strength of concrete using a cylinder placed horizontally and compressed diametrically.

• It is the lowest among all because concrete is inherently weak in tension.

• Typical value: 8–12% of cube compressive strength.

 Modulus of Rupture

• Also known as flexural strength, it represents the tensile strength of concrete under bending.

• Higher than split tensile strength but still much lower than compressive strengths.

• Generally 10–15% of cube compressive strength.

Cylinder Strength

• Measures compressive strength using a cylindrical specimen (150 mm × 300 mm).

• Lower than cube strength due to less confinement and aspect ratio effects.

• Typically 80% of cube strength.

 Cube Strength

• Standard compressive strength measured using 150 mm cube specimens.

• Highest among all due to uniform load distribution and shape effect.

• Used as the design strength in most Indian codes (e.g., M20, M25 grades).

Additional Information1. Split-Tensile Strength (Indirect Tensile Test)

• Test Method:
  A cylindrical concrete specimen is placed horizontally and loaded diametrically in compression until failure.
  The compressive force induces tensile stress perpendicular to the loading direction, causing the specimen to split.

• Specimen Size:
  Standard cylinder of 150 mm diameter × 300 mm height.

 Modulus of Rupture (Flexural Strength Test)

• Test Method:
  A beam specimen is placed on two supports and loaded either at one-third points (two-point loading) or at the center (single-point loading) until failure.

• Specimen Size:
  Standard size is 100 mm × 100 mm × 500 mm or 150 mm × 150 mm × 700 mm.

• Code Reference:
  IS 516:1959 (Section on Flexural Strength).