Geoscience Reference
In-Depth Information
Table 8.3
Physical properties of peat based on location (
after
Huat, 2004).
Natural
Unit
Specific
Organic
water content
weight,
γ
gravity
content
Soil deposits
ω
o
(%)
(kN m
−
3
)
G
s
(%)
Fibrous peat,
370-450
8.7-10.4
-
-
Quebec
Fibrous peat
310-450
10.5-11.1
-
65-85
Antoniny, Poland
Fibrous peat,
865-1400
10.2-11.3
-
98-99
Co. Offaly Ireland
Amorphous peat,
450
10.2
-
80
Cork, Ireland
Cranberry bog peat,
759-946
10.1-10.4
-
60-77
Massachusetts
Austria
200-800
9.8-13.0
-
-
Japan
334-1320
-
-
20-98
Italy
200-300
10.2-14.3
-
70-80
USA
178-600
-
-
-
Canada
223-1040
-
-
17-80
Hokkaido
115-1150
9.5-11.2
-
20-98
West Malaysia
200-700
8.3-11.5
1.38-1.70
65-97
East Malaysia
200-2207
8.0-12.0
-
76-98
Central Kalimantan
467-1224
8.0-14.0
1.50-1.77
41-99
accounts for more than 90% of the greenhouse gas emissions. Sometimes the plant
fibres are visible, but in the advanced stages of decomposition they may not be evident.
Peat will ultimately be converted into lignite coal over geologic periods of time provided
favourable conditions prevail. Also, the fresher the peat, the more fibrous material it
contains, and (as far as engineering is concerned), the more fibrous the peat, the
higher are the shear strength, void ratio and water content. In fact, the properties of
peat are greatly dependent on the detailed formation of peat deposits. This means that
peat at different locations will have different properties (Table 8.3). Commonly, the
classification of peat is based on fibre content, organic content and ash content.
The degree of decomposition varies throughout peat, since some plants (or parts
of them) are more resistant than others. Also, the degree of decomposition of peat
depends on a combination of conditions, such as the chemistry of the water supply, the
temperature of the region, aeration and the biochemical stability of the peat-forming
plant (Lishtvan
et al.
, 1985).
Much of the information about the physical properties of peat has been included
in Chapters 2-5. Tropical peat is generally non-homogeneous compared with temper-
ate (fen) peat. As mentioned earlier, the physical properties of peat are the result of
many factors, including wood content, degree of decomposition or humification, bulk
density, porosity, water holding properties and hydrology. Tropical peat, for instance,
is generally reddish brown to very dark brown in colour depending on the stage of
decomposition.
