Sampling & Acceptance Chain (IS 3535 → IS 4031 / IS 4032)
OPC 43 acceptance is valid only as a chain: define the lot, draw a representative composite sample per IS 3535, run the physical (IS 4031) and chemical (IS 4032) tests with standardised sand (IS 650) and consistency-set water (IS 4031 Part 3), then accept/reject the LOT against IS 8112. Cement defect propagates into every pour, so a non-representative sample certifies nothing.
Key Requirements
•Define the lot (grade/source/dispatch); sample representatively per IS 3535
•Seal the sample airtight immediately (cement carbonates/absorbs in hours) and test promptly
•Run IS 4031 physical (IS 650 sand, IS 4031 Part 3 consistency water) + IS 4032 chemical
•Judge the LOT against IS 8112 chemical and physical requirements
•Re-sample per consignment — a later sub-standard delivery is invisible otherwise
Practical Notes
✓Disputed cement results very often unwind to the sample (convenience-drawn / moisture-degraded), not the cement or the test — witness the sampling.
✓Same acceptance chain regardless of plant type (integrated/mini) — quality is verified on the delivered cement by test.
Common Mistakes
⚠Bag-tag / convenience acceptance instead of a representative IS 3535 sample.