Turn your 1 m³ mix design into a weigh-batcher-ready trial batch sheet — SSD-to-wet aggregate conversion, free-water credit and admixture dose in mL. Pure arithmetic; your mix stays yours.
Mix design per m³ (SSD basis, kg)
Aggregate moisture (%)
Water absorption, SSD (%) — from your aggregate test report
Free moisture = moisture − absorption. Wet stock (moisture > absorption) carries surface water — credited against batch water. Dry stock (moisture < absorption) absorbs the deficit from the mix — added back so your water–binder ratio holds.
Batch sheet — L (factor )
Every ingredient is multiplied by the batch factor (batch litres ÷ 1000). Moisture correction follows standard lab practice: weigh aggregates at their moist stock mass — SSD × (1 + moisture%) — and credit the free water they carry against the batch water, so the water–binder ratio you designed is the one you actually batch.
Admixture is dosed as % of total binder (cement + fly ash + GGBS) and read in mL (≈1 kg/L). This tool does arithmetic only — the mix design itself must come from your IS 10262 spreadsheet or consultant.
Given: M25-ish trial — cement 320, fly ash 80, sand 780, 20 mm 860, 10 mm 410 kg/m³, water 160 L, PCE at 1.2% of binder; batch 50 L; sand at 3% moisture with 1.2% SSD absorption — 1.8% free.
Factor 0.05 → cement 16.0 kg, fly ash 4.0 kg, sand 39.0 SSD → 40.17 kg wet
Free water from sand = 1.17 L → batch water = 8.0 − 1.17 = 6.83 L
Admixture = 400 × 1.2% × 0.05 = 0.24 kg = 240 mL
30–60 L is typical: enough for three 150 mm cubes plus slump and density tests, small enough to mix by hand or pan mixer. Keep the batch at least 25 L so weighing errors on the smallest ingredient (admixture) stay proportionate.
Wet sand carries water on its surface. If you batch the SSD weight from moist stock you would short the aggregate and add the design water on top — raising the effective w/c. Weighing wet and deducting the carried moisture keeps both the aggregate content and the w/c exactly as designed.
That is likely a wet-washed or rain-soaked stock with running water in the pores, not surface moisture — the simple correction no longer holds. Drain the stockpile, re-test moisture, and batch the next day. The tool caps at 12% for exactly this reason.
Yes — same product, same dose basis. Changing the admixture between trial and production invalidates the workability and strength relationship the trial exists to establish. Record brand, type and dose on every batch sheet.
Often used together with this calculator — pick the next step in your design or QA loop.
Updates live from the calculator above — click Make batch sheet to refresh.
Deep dive: read the full significance guide — the code clauses, assumptions and site meaning behind these numbers.