Concrete grade and batching as specified, not "as usual"
Why — act while you have leverage
The grade on the drawing is a structural decision. A site that batches by headpan and calls it M20 is producing something nobody has calculated, and the cube test will tell you months later — after the slab is up.
What to look at
- The grade for THIS element read off the drawing before the pour
- A gauge box and a measured water quantity, or a batching plant docket
- How wet the concrete is (slump) checked rather than judged by eye
- Mix design or batching plant dockets for the pour
Documents to ask for
- Mix design or batching plant dockets for the pour
How to check it yourself
Nominal mix proportions are by volume with a gauge box, or the concrete is design-mixed and comes with a mix design. Confirm the grade against the structural drawing element by element — footings, columns and slabs are frequently different, and pouring one grade for everything is a saving somebody is making. Water is measured, not run in from a hose until it looks right.
Where this comes from: IS 456:2000 cl. 9 (concrete mix proportioning) and cl. 6 (grades); IS 10262 for mix design (indian standard or building code)