Aggregate particle density and water absorption
Enter the weighings of the pyknometer or wire-basket method and get the water absorption and the three particle densities of EN 1097-6. The absorption needs only the two masses in air. No sign-up.
Result
Enter M1 and M4 to see the water absorption.
For guidance only. A test report must follow the full procedure of EN 1097-6, including the preparation of the sample and the surface-dry state.
How density and absorption are calculated
The sample is soaked for 24 hours, weighed with water (M2) - in the basket under water, or in the pyknometer filled with water - brought to the saturated surface-dry state and weighed (M1), then dried to constant mass (M4). M3 is the empty basket under water, or the pyknometer filled with water only. The water absorption is the water the saturated particles hold, as a share of their dry mass:
WA24 - water absorption (%) · M1 - saturated surface-dry mass (g) · M4 - oven-dried mass (g) · ρw - density of water (Mg/m³)
The densities divide the dry or saturated mass by the volume of water the particles displace, M1 − (M2 − M3) for the whole particle or M4 − (M2 − M3) without its open pores: ρa = ρw·M4 / (M4 − (M2 − M3)), ρrd = ρw·M4 / (M1 − (M2 − M3)), ρssd = ρw·M1 / (M1 − (M2 − M3)). Densities are reported to 0.01 Mg/m³, absorption to 0.1 %.
Worked example
M1 = 1015.0 g, M4 = 1000.0 g, M2 = 1265.0 g, M3 = 640.0 g: WA24 = 100 × 15 / 1000 = 1.5 %. The particles displace 1015 − 625 = 390 g of water, so ρrd = 0.998 × 1000 / 390 = 2.56 Mg/m³.
Questions engineers ask
Which density goes into the mix design?
Mix design by absolute volume uses the saturated surface-dry density (ρssd) together with the absorption, because the aggregate in fresh concrete is assumed to be saturated. The oven-dried density (ρrd) is used when quantities are calculated on dry aggregate.
Pyknometer or wire basket?
EN 1097-6 uses the wire basket for particles from 31.5 to 63 mm, the pyknometer for 4 to 31.5 mm and a separate pyknometer procedure for 0.063 to 4 mm. The formulas are the same; only the weighing in water differs.
What absorption is normal?
Dense natural aggregates usually absorb below 1 to 2 %. Higher values point to porous rock, recycled or lightweight aggregate - several product standards and national annexes set limits - EN 12620 uses 1 % as a screening value - above which freeze-thaw resistance has to be shown by testing.
Keeping aggregate results for every delivery?
LabFlow keeps each weighing with the sample it belongs to, calculates the densities and absorption as they are entered, and puts them on an approved report your client downloads from their own portal.