4.4 QUALITY CONTROL OF CEMENT
4.4.1 Introduction
Cement is the most essential binding material in construction. Its quality directly affects the strength, durability, and overall performance of concrete and mortar. Hence, strict quality control during manufacture, storage, transportation, and field application is vital to ensure reliable construction outcomes.
4.4.2 Objectives of Quality Control
- Ensure conformity to specified chemical and physical properties.
- Maintain consistency in quality between different batches.
- Prevent the use of deteriorated or adulterated cement.
- Establish standardized procedures for sampling, testing, and acceptance.
4.4.3 Relevant Indian Standards for Cement Quality
| IS Code |
Title / Description |
| IS 269 |
Ordinary Portland Cement (33 Grade) — Specification |
| IS 8112 |
Ordinary Portland Cement (43 Grade) — Specification |
| IS 12269 |
Ordinary Portland Cement (53 Grade) — Specification |
| IS 1489 (Part 1 & 2) |
Portland Pozzolana Cement — Specification |
| IS 455 |
Portland Slag Cement — Specification |
| IS 4031 (Part 1–15) |
Methods of Physical and Chemical Tests for Hydraulic Cement |
| IS 650 |
Standard Sand for Testing of Cement |
| IS 3535 |
Methods of Sampling Hydraulic Cement |
(Note: Students should always refer to the latest revision of the IS codes.)
4.4.4 Stages of Quality Control
a) At the Manufacturing Plant
- Continuous control of raw mix proportioning and kiln burning conditions.
- Monitoring clinker composition, free lime, and gypsum content.
- Routine testing of fineness, setting time, and compressive strength.
- Proper silo storage to prevent moisture ingress.
b) During Storage and Handling
- Store in a dry, ventilated, elevated godown.
- Keep bags on wooden pallets and away from walls.
- Follow First-In-First-Out (FIFO) policy.
- Inspect for lumps and discoloration before use.
c) At Construction Site
- Perform field identification tests before use.
- Collect samples for laboratory testing at regular intervals as per IS 3535.
4.4.5 Field Tests on Cement
| Test |
Procedure / Observation |
Indication |
| Visual Inspection |
Check for colour and lumps |
Uniform grey colour, no lumps |
| Feel Test |
Rub between fingers |
Smooth, not gritty |
| Float Test |
Sprinkle cement on water |
Should float momentarily before sinking |
| Smell Test |
Detect earthy odour |
No earthy smell — indicates absence of adulteration |
| Block Strength Test |
Make 1:3 cement–sand block |
Should gain strength after 7 days |
| Setting Time (Field) |
Observe with gauging |
Should not set instantly |
4.4.6 Laboratory Quality Tests (as per IS 4031 Series)
For detailed laboratory test procedures, click here, and for video demonstrations, click here.
| Test |
Description / Purpose |
Typical Requirement (for OPC 43 Grade) |
Standard Reference |
| Fineness (Blaine’s Air Permeability Method) |
Determines surface area of cement particles; affects hydration rate and early strength. |
≥ 225 m²/kg |
IS 4031 (Part 2) |
| Standard Consistency |
Establishes the water content required to produce a standard cement paste for further tests. |
26–33% |
IS 4031 (Part 4) |
| Initial Setting Time |
Time taken by cement paste to start hardening; indicates workable time during concreting. |
≥ 30 minutes |
IS 4031 (Part 5) |
| Final Setting Time |
Time required for the paste to become rigid; influences construction scheduling and finishing. |
≤ 600 minutes |
IS 4031 (Part 5) |
| Soundness (Le Chatelier Method) |
Measures volumetric stability; detects excess free lime or magnesia causing expansion. |
≤ 10 mm expansion |
IS 4031 (Part 3) |
| Compressive Strength of Mortar Cubes |
Determines load-bearing capacity of cement; major acceptance test. |
≥ 23 MPa (3 days), ≥ 33 MPa (7 days), ≥ 43 MPa (28 days) |
IS 4031 (Part 6) |
| Loss on Ignition (LOI) |
Measures moisture, CO₂, and unburnt materials; higher LOI means poor storage. |
≤ 5% |
IS 4032 |
| Insoluble Residue |
Indicates non-cementitious impurities such as sand, clay, or dust. |
≤ 2% |
IS 4032 |
| Lime Saturation Factor (LSF) |
Ensures balanced proportion of lime with silica, alumina, and iron oxide; affects soundness. |
0.66 – 1.02 |
IS 4032 |
4.4.7 Common Defects and Causes
| Defect |
Probable Cause |
Effect on Concrete |
| Lumpy Cement |
Moisture absorption |
Reduced strength |
| Low Fineness |
Improper grinding |
Low early strength |
| Excess Gypsum |
Poor control |
Delayed setting |
| Unsound Cement |
Excess lime/magnesia |
Expansion and cracking |
| High LOI |
Poor storage |
Weak bonding, lower durability |
4.4.8 Acceptance Criteria
- Cement must conform to relevant IS specifications for its type and grade.
- Manufacturer’s Test Certificate (MTC) must accompany each batch.
- Field/lab test results should match certificate values within ±5%.
- Doubtful results require retesting from an approved laboratory.
4.4.9 Modern Methods of Cement Quality Control
- X-ray fluorescence (XRF) for rapid chemical composition analysis.
- Laser particle size analysis for fineness measurement.
- Automatic weigh feeders and computerized kiln control systems for process uniformity.
- Grinding aids and mineral performance enhancers for improved efficiency and consistency.
4.4.10 Summary Table
| Aspect |
Key Points |
| Testing Standards |
IS 4031 Series |
| Field Checks |
Colour, texture, lumps, float test |
| Main Lab Tests |
Fineness, Setting, Soundness, Strength |
| Key Parameters |
Strength, Setting Time, Soundness |
| Common Issues |
Moisture, Unsoundness, Low Fineness |
| Modern Control Tools |
XRF, Laser Analysis, Auto Mix Control |
4.4.11 References
- IS 269 — Ordinary Portland Cement – Specification
- IS 4031 (Part 1–15) — Methods of Physical and Chemical Tests for Hydraulic Cement
- IS 650 — Standard Sand for Testing of Cement
- IS 3535 — Methods of Sampling Hydraulic Cement
- ASTM C150 — Standard Specification for Portland Cement