Quality
What IS 383 Means for Your Sand — and Why Washing Matters
When a supplier says 'IS 383 grade,' what are they actually promising? A plain-language guide to the standard that governs concrete sand.
IS 383:2016 is the Bureau of Indian Standards specification for coarse and fine aggregates used in concrete. When sand is described as "IS 383 grade," it means the material is meant to fall within the size grading and cleanliness limits this standard lays down. Here is what that involves, without the jargon.
Grading zones
The standard sorts fine aggregate (sand) into four grading zones, from Zone I (coarsest) to Zone IV (finest), based on how much sand is retained on each test sieve. For general structural concrete, sand in the middle zones — commonly Zone II — works well because it balances workability and strength. The point of grading is consistency: a well-graded sand has a good spread of particle sizes so it packs densely with minimal gaps.
Cleanliness limits
IS 383 also limits deleterious materials — silt, clay, dust and organic matter that weaken concrete. Too much of these, and cement cannot bond properly to the sand. This is the single biggest quality issue with sand, and it is exactly what washing addresses.
Why washing keeps sand in spec
Crushing rock produces a lot of ultra-fine dust along with usable sand. If that dust stays in, the sand carries excess fines and silt and can fall outside the standard. A washing plant runs the crushed sand through water to carry away the lightest fines and silt, leaving clean, correctly graded sand behind.
Why it matters to your wallet
Clean, well-graded sand needs less cement and less water to reach the same strength, because none of it is wasted coating silt. So "IS 383 washed sand" is not just a quality badge — it directly affects how much cement you burn through and how durable the finished concrete is.
What to ask your supplier
- Is the sand washed, and what grading zone does it target?
- Can you provide a sieve analysis report with the delivery?
- What is the typical silt content?
A supplier who can answer these confidently — and back it with a test report — is selling you concrete sand, not just "sand."
Need this delivered to your site?
Wilgro Infra supplies washed M-Sand, P-Sand and graded aggregates across Sarjapur, Hosur, Attibele and all over Bangalore — by the tonne or by the load, with sieve reports on request.