EXAMPLE PROBLEM III-1-4

FIND:

The volume concentration, the porosity, the voids ratio, the dry bulk density, and the saturated bulk

density of the densely packed aggregate given in example problem III-1-2.

GIVEN:

18.1 grams of dry beach sand exactly fills a small container having a volume of 10.0 cm3 after the

filled container is strongly vibrated. When this amount of sand is poured into 50.0 ml of water that is

subjected to a strong vacuum, the volume of the sand-water mixture is 56.8 ml.

SOLUTION:

It is important to recognize the difference in the volume of the grains themselves, 6.8 cm3

(= 56.8 - 50) (a milliliter is a cubic centimeter), and the volume of the aggregate (the grains

plus the void spaces), 10 cm3.

The volume concentration is the ratio of solid volume to total volume:

The porosity is the ratio of void space to total volume, which, from Equation 1-13 is:

The voids ratio is the ratio of pore space to solid space, which,

from Equation 1-13 is:

The dry bulk density from Equation 1-14 is:

Dry Bulk Density = 0.68 * 2,660 kg/m3 = 1,800 kg/m3

The saturated bulk density from Equation 1-15 is:

Saturated Bulk Density = (0.68*2,660) +(0.32*1,000) kg/m3 = 2,100 kg/m3

These bulk density values are within the expected range as shown in Table III-1-6A.

III-1-32

Coastal Sediment Properties

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