Generally, soils with organic content that greater than

Generally, peat has recognize as organic soil
high that has high natural moisture content content due to its natural
water-holding capacity. The high natural water holding capacity of peat soil is
due to the structure of soil that have characterized by organic coarse
particles (known as fiber) which can hold a considerable amount of water since
the soil fibers are very loose and hollow (Bujang and Kazemian 2011). From the
result from table 1, the value of natural moisture content at burnt peat area
has ranged between 354 to 709 %, as suggested by Huat and B. K. (2004) that
moisture content range values of peat soil of West Malaysia is between 200 to
700%. In geotechnical engineering aspect, organic soils with organic content
that greater than 75% are known as ‘peats’ (Bujang, 2004). From the result, all
of the burnt peat soil samples contain more than 75% of organic matter with
less than 25% of ash content. Normally, the volume of peat samples were higher
in wet condition and started to decrease when it getting dried and shrunk. It
can be seen from figure 9, the percentage of shrinkage limit getting higher
with the increasing of moisture content of burnt peat soil. With addition of
Ordinary Portland Cement (binder) and mineral soil (filler), it might fill the
air void of grain particles; thus the tendency of stabilized burnt peat can be
reduced. Abu Bakar (2008) studied the properties of stabilized peat (Banting peats)
with and without the addition of sand concluded that the shrinkage of
stabilized without sand was reduced with the increase of admixture content and
curing time. From the result (table 1 and figure 9), the linear shrinkage was
significantly reduced by the addition of admixture and curing period of
stabilized peat with addition of mineral soil filler particles.

            In
Unconfined Compressive Strength (UCS) test, there is no radial stress acted to
the sample (?=0) which is the
axial load is increasing rapidly until the samples of soil tend to fail until
it cannot support any additional load. The pore water cannot drain anymore from
the soil since the loading acted quickly and making the soil sample is sheared at
a constant volume. As indicated by Kalantari and
Huat (2008), the most guideline of utilizing the Air Curing Technique to settle
peat is the natural moisture content of peat soil sample has ranged between 198
to 417%. From the result, the value of UCS strength increased with addition of
natural moisture content of peat sampling but the strength started to decrease
when the value of moisture content surpassed 425% in intersect line 1. The UCS
strength value seem to be a slower rate of strength gain after 14 days of
curing. The highest value of UCS value recorded at point BP-2 with 412.17 kPa
which  has 425.34% of moisture content
indicates the optimum content of water  needed to gain the maximum UCS strength of  burnt peat samples. Water content capacity is
the most important properties in determination of peat soil. It can be seen
from the result at table 1, whereas the lowest value of UCS strength recorded
at BPL-2-4 (intersect line 2) with 121.48 kPa and BP-6 (intersect line 1) with
value of 149.59 kPa, which has the lowest and the highest value of natural
moisture content; BPL-2-4 (205.56%) and BP-6 (709.805) respectively. This is
indicate that moisture content give the big impact to the strength of burnt
peat stabilization. According to Chen and Wang (2006), the large amount of
organic matter present in peat soil allow peat to hold a large water rentation
capacity; resulting a high natural moisture content and will caused the organic
particles to adsorb to the surface of the cement and also to the surfaces of
solid mineral particles. This will prevent the hydration process of cement
product and inhibiting hydration reaction between solid soil particles and the
hydration product; thus affected the increment of the strength of peat-cement
admixture. As the air curing time for the stabilized peat samples was
increased, the moisture content decreased, thus weight of ratio Water/Weight of
Cement (W/C) was reduced, and as a result the stabilized peat samples were
hardened and gaining significant strength (Behzad and Bujang, 2008).