Rejected first-class bricks and lumpy cement before Monday's brickwork
At a two-storey panchayat school site in Bankura, 5,000 burnt-clay bricks arrive from a new kiln and the supplier bills them as first class. The mason has already laid about 300 of them in the plinth. You draw ten bricks at random from five different stacks and send five for testing. Results: water absorption averages 21.5% (individual values 19, 22, 23, 21, 22), compressive strength averages 8.6 N/mm² with the weakest brick at 6.4 N/mm², efflorescence is rated slight, three bricks show hairline cracks and one has a soft, unburnt core when broken. Separately, 60 bags of OPC delivered in June have been stored in a godown with a leaking asbestos roof. Today is mid-September; about 15 bags contain hard lumps that do not crumble under finger pressure, the rest look normal. Load-bearing brickwork above plinth starts on Monday and the client wants every brick and every bag used to keep the cost down.
1. Decide whether the consignment can be accepted as first class, and state where each category of brick may or may not be used.
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Test the results against the usual classroom limits for burnt-clay building bricks (IS 1077 grade plus the standard first/second/third class classification):
- Water absorption - first class not more than 20% (many texts say 15%); second class up to 22%. The average of 21.5%, with two individual values above 20%, fails first class and sits inside the second-class band.
- Compressive strength - first class average 10 N/mm² or more; second class 7.5 N/mm² or more. The average of 8.6 N/mm² is second class, and the weakest brick at 6.4 N/mm² is below even that.
- Efflorescence - a 'slight' rating is permitted even for first class, so this is not on its own a ground for rejection.
- Cracks and unburnt core - these are burning/handling defects. An unburnt core means under-firing: low strength, high absorption, poor durability. Such bricks are not acceptable in any sound work.
Judgement: reject the lot as first class. Do not allow it in load-bearing walls above plinth, in the DPC course, or in exposed external faces. Sound bricks (no cracks, no unburnt core) may go into 125 mm internal partitions, parapet filling and similar non-structural work at a renegotiated second-class or reject rate. Return the cracked and unburnt bricks and demand replacement against the bill. If the supplier disputes the grading, send a fresh random sample to a laboratory before any load-bearing use, and record the rejection in the site order book so that the 300 bricks already in the plinth can be reviewed.
2. What is your decision on the 60 bags of cement, and what storage corrections do you order?
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Hard lumps that do not break under finger pressure mean the cement has partly hydrated. Its strength is now unpredictable and it cannot be relied on in structural concrete, load-bearing mortar or structural plaster. Reject those 15 bags outright - sieving or re-powdering does not restore the cement.
The other 45 bags are about three months old and have been under a leaking roof, so they are 'suspect', not automatically condemned. Open several bags from different positions in the stack. Free-flowing powder, no caking on the inner folds of the paper, no stained wrappers: usable, but reserve it for non-structural work such as flooring bedding or filling. Lumpy or caked bags go with the rejected lot.
Storage corrections to issue immediately:
- Shift everything to a dry, well-ventilated room away from the leaking roof.
- Stack on timber pallets at least 150 mm above the floor and 300–450 mm clear of walls.
- Maximum stack height about 10 bags, cross-stacked, oldest used first.
- Never store cement against a wall that takes damp, and never on the floor.
- Keep a joint record signed by the contractor and the client: the cost of the rejected cement falls on the supplier/storer, not on the client as an extra item.
3. Before Monday, what sampling, testing and documentation will you insist on, and what instruction do you give the mason?
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Sampling: draw at least 10 bricks at random from five different stacks - never from the top layer only and never from one pile - because kiln quality varies from stack to stack. Label the sample with stack numbers, bill number, date and the name of the person who drew it.
Testing: five bricks for water absorption (24-hour cold soak) and five for compressive strength, with the frog filled and the two halves bedded flat; keep the individual results, not just the average, because the 6.4 N/mm² brick is the real warning. Retain the broken pieces until the supplier accepts the report.
Documentation: a material inspection report and a rejection memo in the site order book, a copy of the test report, a revised bill at the corrected rate, and a written instruction that the balance of the consignment is not to be used pending decision.
Instruction to the mason: stop lifting bricks from the delivered stacks; finish nothing further above plinth with this lot until the grading is settled. Because 300 bricks are already in the plinth, check whether they came from the same stacks - if they show cracks or unburnt cores, the plinth face and DPC must be inspected before the walls rise, since a weak plinth course cannot be corrected later.