Figure 4. Dredged material water content as a function of bulk wet density

ERDC TN-DOER-D1

August 2004

materials. The correlations discussed below enable prediction of material properties including

water content, wet bulk density, percent solids, void ratio, porosity, specific gravity, and Atter-

berg limits without conducting time-consuming and expensive standardized laboratory testing.

Combining these experimental property correlations with published correlation equations enables

expedient screening-level assessment of engineering behavior properties including undrained

shear strength, consolidation, and permeability (saturated hydraulic conductivity) parameters

without waiting for the prerequisite laboratory testing.

Method for predicting unknown water content. Given a dredged material with an

unknown water content (defined as the weight of water divided by weight of dry solids), the

standard procedure to determine water content involves an oven or microwave for drying to a

constant mass (ASTM 1998). An alternate and much faster method is to measure the wet bulk

unit weight (commonly called the bulk density) using a simple mud balance device (ASTM

1984) and apply the Equation 1 correlation (also shown in Figure 4):

Water content %= 2 1011 γ-4.7128

(1)

where γ = saturated wet bulk density, lb/cu ft

Equation 1 was experimentally obtained using 146 data points from fine-grained dredged

material.

Figure 4. Dredged material water content as a function of bulk wet density (same as bulk unit weight) (to

convert pounds per cubic foot (pcf) to Newtons per cubic meter, multiply by 157)

Method for predicting unknown Atterberg limits. Atterberg limits are defined by the

shrinkage, plastic, and liquid limit water contents of fine-grained soils, along with the plasticity

index and the liquidity index. The shrinkage limit is of little concern for dredged materials, but