Total Coarse Aggregate Content
IS 10262:2019 Table 5 gives the volume of coarse aggregate per unit volume of total aggregate, based on the nominal maximum aggregate size and the sand grading zone. This page explains the table and the corrections applied to it. Open the calculator with a nominal aggregate size filled in.
Table 3 values and corrections
The Table 3 base value is for a w/c of 0.50. It is adjusted by about +0.01 for every 0.05 that the adopted w/c is below 0.50, and −0.01 for every 0.05 above 0.50. For pumpable concrete, the coarse fraction is reduced — multiply the corrected value by about 0.90.
| Nominal maximum aggregate size | Coarse aggregate volume fraction (Zone I sand) |
|---|---|
| 10 mm | 0.44 |
| 20 mm | 0.60 |
| 40 mm | 0.69 |
Values shown are for Zone I sand at w/c 0.50; they rise for finer sand zones. The calculator uses the exact value for your selected zone.
Worked example
For 20 mm aggregate, Zone I sand, the base value is 0.60. An adopted w/c of 0.40 is 0.10 below 0.50, so add 0.02 — giving 0.62. For pumpable concrete, multiply by 0.90 — giving about 0.56 as the coarse fraction, so the fine fraction is about 0.44.
Questions this page answers
Why adjust for w/c?
Lower w/c mixes are more cohesive and can carry slightly more coarse aggregate for the same workability, which is why the fraction increases as w/c drops below 0.50.
Is that the total coarse aggregate?
Yes — it gives the total coarse aggregate volume. Splitting that total into individual sizes such as 20 mm and 10 mm is a separate step; see the aggregate blend page.