👉HOLLOW CONCRETE BLOCK (HCB) – CLASS B LABORATORY TESTS

💫Class B Hollow Concrete Blocks are used for non-load bearing walls or medium-strength construction.

🚧To certify quality, the following laboratory tests are performed.

✅ 1. Compressive Strength Test

⏺Standard: ASTM C140
Purpose: To measure block strength.

❇️Typical Requirement for Class B HCB:

Minimum compressive strength: 3.5 MPa to 5.0 MPa (varies with project spec)

Test 3 blocks (average value)

✅ 2. Dimension & Shape Tolerance

Standard: ASTM C140 / ES Standard
Purpose: Check if the block meets size and shape requirements.

Requirements (typical):

Length, width, height within ±3 mm tolerance

Faces should be flat and perpendicular

No large cracks or visible defects

✅ 3. Density Test (Dry Density)

Purpose: Confirm block classification (lightweight, medium, or normal).

Typical values:

1400 – 1700 kg/m³ for Class B HCB

✅ 4. Water Absorption

Standard: ASTM C140
Requirement:

Water absorption ≤ 12–15%

High absorption indicates weak block quality.

✅ 5. Block Weight Measurement

Purpose: Ensure consistency and structural performance.

Values depend on block size (e.g., 150 mm, 200 mm thickness).

✅Optional Tests (if required)

Ultrasound pulse velocity test – for uniformity

Efflorescence test – check salt content

Moisture content

📌 Summary Table for Easy Use

Test Purpose Typical Requirement (Class B)

Compressive Strength Strength ≥ 3.5 – 5.0 MPa
Dimensions Size accuracy ± 3 mm tolerance
Density Quality classification 1400–1700 kg/m³
Water Absorption Durability ≤ 12–15%
Weight Consistency As per design block type

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