Concrete unit weight, yield and gravimetric air

AASHTO T 121 · ASTM C138

Explained inUnit Weight and Yield of Fresh Concrete

Calculator

Concrete unit weight, yield and gravimetric air

AASHTO T 121 · ASTM C138

Weigh a filled measure of known volume, then take the batch masses from the ticket. A low density usually means more air or water than designed, and more volume than was paid for per sack of cement.

Units US customary SI (metric)

Mass of the measure, M_m, lb

Mass of measure and concrete, M_c, lb

Volume of the measure, V_m, ft³

From the measure’s standardization: the mass of water that fills it ÷ the density of water at that temperature.

From the batch ticket

Total mass of the batch, W, lb

Cement and other cementitious materials, aggregates as batched, and all the water: at the plant, in transit and on site.

Cementitious materials in the batch, N_t, lb (optional)

Volume ordered (design yield), yd³ (optional)

From the mix design

Air-free (theoretical) density, T, pcf (optional)

The batch masses ÷ their absolute volumes, with no air. Leave blank to skip the gravimetric air content.

Specification

Relative yield minimum (optional)

T 121 sets no limit; use your agency’s, if it has one. Leave blank for no check.

Relative yield maximum (optional)

Air content minimum, % (optional)

From your specification’s exposure class.

Air content maximum, % (optional)

Example values: one truckload. Your agency sets any relative yield or air limits.

All tools