The percentage of FSM determined by this method approximates the amount of water by the weight of the sand.

Use these estimates to adjust the mix design.

Fine aggregates have a tendency to bulk (expand in volume) when wetted and when the mass is disturbed. This

factor becomes very important if the concrete is being batched at a mixer by volume; the initial mix design must

be adjusted. The procedure for adjusting the mixing water and sand bulking due to free surface moisture is as

follows:

amount gravel will hod without actually dripping.

yield the weight of the FSM on the aggregates. If the aggregate has an absorption factor rather than FSM

the weight of water needs to be subtracted rather than added.

weights of the aggregates per cubic yard by the weights of the FSM.

from Figure 2-8 on page 2-22. The formula for volume increase is--

Vwet = Vdry x (1 + BF). (V = volume, BF = bulking factor.)

Coarse aggregates do not bulk; therefore, no adjustment is necessary.

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