Figure 15. Comparison of water content definitions

ERDC TN-DOER-D2

September 2004

ASTM water content = ω = Ww/Ws

(1)

Wet (total) weight water content = w = Ww/W

(2)

Volumetric water content = θ = Vw/V

(3)

where Ww = weight of water, Ws = weight of dry solids, W= wet weight, Vw= volume of water,

and V= total volume.

To compare the differences in calculated values,

w% = 100(ω%) / (ω% + 100)

(4)

θ = e / 1+e where e = void ratio = ω Gs

(5)

Figure 15. Comparison of water content definitions

Grain size distributions based on volume instead of weight measurements will introduce

parameter variability when the two methods are compared. For example, Figure 16 shows grada-

tion curves for a sandy dredged material tested on both a weight basis and a volume basis. The

volume basis curve indicates a slightly coarser material, with a 0.1-mm difference in the median

particle sizes.