EM 1110-2-1100 (Part III)
30 Apr 02
Table III-1-4
Densities of Common Coastal Sediments
Density kg/m3
Mineral
Quartz
2,648
Feldspar
2,560 - 2,650
Illite
2,660
Montmorillonite
2,608
Kaolinite
2,594
Calcite
2,716
Aragonite
2,931
Dolomite
2,866
Above sand size, sediments encountered in coastal engineering are usually composites of several minerals,
that is, rocks. Table III-1-5 lists densities of rocks commonly encountered. These rocks are also used for
riprap, which are large sedimentary particles. Lines 5 and 6 of Table III-1-5 deal with carbonate rocks, the
dolomites and limestones. Note 3 of Table III-1-5 suggests that typical dolomites are denser, less porous, and
geologically older than typical limestones.
Table III-1-5
Average Densities of Rocks Commonly Encountered in Coastal Engineering
Mass Density, kg/m3
Number
Rock Type
Number of Samples
1
Basalt
323
2,740
2
Dolerite-Diabase
224
2,890
3
Granite
334
2,660
4
Sandstone
107
2,220
5
Dolomite
127
2,770
6
Limestone
182
2,540
Notes:
1
Basalt and dolerite (or diabase) in lines 1 and 2 are fine-grained dark igneous rock often classed together as trap rock for
engineering purposes.
2
Lines 1, 2, 3, 4 from Table 5 of Johnson and Olhoeft (1984). Lines 5, 6 from Table 4-4 of Daly, Manger, and Clark (1966).
3
Line 5 is the average of 127 samples from 3 dolomites or dolomitic limestones. Line 6 is the average of 182 samples from
5 limestones. The rocks in line 5 are denser and older than those in line 6. Average porosity of rocks in line 5 # 3.0%; in line 6
average porosity is between 3% and 17%. Rocks in line 5 are older than Carboniferous.
c. Specific weight and specific gravity. The specific weight of a material is its density times the
acceleration of gravity g. In SI units, the acceleration of gravity is 9.807 m/s2, and thus, specific weight is
measured in kilograms per meter squared per second squared (kg/(m2 * s2)). The specific gravity of a material
is its density divided by the density of water at 40 C, which is 1000.0 kg/m3. Specific gravity is a
dimensionless quantity.
d. Strength.
(1) The material strength of a particle is the maximum stress which the particle can resist without failing,
for a given type of loading. The SI unit of stress is the Pascal, and the convenient Pascal multiple is 1 million
Pascals, or 1 mega Pascal (MPa). "Strength" in this section is unconfined ultimate strength in compression,
III-1-16
Coastal Sediment Properties
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