Quality control – Sampling, Acceptance criterion, Code of practice and guidelines for different building materials such as Cement, Aggregates, Admixtures, Concrete, Bricks, Steel, and Timber.
Definition: Quality control (QC) in construction ensures that building materials and workmanship conform to specified standards, ensuring safety, durability, and serviceability of structures.
Objectives:
Key Components of QC:
| Material | Relevant IS Code | Sampling Method | Typical Quantity for Testing |
|---|---|---|---|
| Cement | IS 3535 | Random sampling from 20 bags or batch | Minimum 12 kg composite sample |
| Aggregates | IS 2430 | Random samples from conveyor or truck loads | 30 kg for coarse, 10 kg for fine |
| Concrete | IS 1199, IS 516 | Cube sampling from fresh mix | 3 specimens per test |
| Bricks | IS 5454 | Random 20 bricks from batch | 5 for compression, 5 for water absorption |
| Steel | IS 1786 | 1 sample per heat/lot | 3 specimens for tensile test |
| Timber | IS 1734 | From each species or lot | Minimum 3 samples for mechanical test |
Note: Samples must be representative, properly labeled, and stored to prevent contamination before testing.
Acceptance is based on comparing test results with the minimum required standards specified in IS codes.
| Material | Acceptance Parameter | Standard Reference | Typical Requirement |
|---|---|---|---|
| Cement | Fineness, soundness, compressive strength | IS 269, IS 4031 | ≥ 33 MPa (OPC 33 grade) |
| Aggregates | Sieve analysis, impact, crushing value | IS 383 | ≤ 30% impact value |
| Concrete | Compressive strength | IS 456, IS 10262 | Mean ≥ fck + 1.65 s |
| Bricks | Compressive strength, water absorption | IS 1077 | ≥ 7.5 MPa, ≤ 20% |
| Steel | Tensile strength, elongation | IS 1786 | ≥ TMT Fe 500 → 545 MPa |
| Timber | Moisture, bending, crushing strength | IS 287 | Moisture ≤ 12–15% |
Each sub-section will have:
Essential QC records:
Checklists:
| Material | Key IS / ASTM Codes |
|---|---|
| Cement | IS 269, IS 4031, IS 12269 |
| Aggregates | IS 383, IS 2386 (Parts I–VIII), IS 2430 |
| Admixtures | IS 9103 |
| Concrete | IS 456, IS 10262, IS 516 |
| Bricks | IS 1077, IS 5454 |
| Steel | IS 1786, IS 1608, IS 2062 |
| Timber | IS 287, IS 1708, IS 1734 |
Collect representative samples of cement, coarse and fine aggregates, and bricks from site stockpiles. Record:
Prepare and test concrete cubes as per IS 516. Record age, load at failure, and compute compressive strength.
Prepare a summary table comparing test results vs. IS requirements for 3 materials used at your site.