Sains Malaysiana, 2016;45:1679-1687.

Abstract

Peat soil is characterized by its high content of decomposed organic matter. Majority of areas occupied by peatland have
been developed for agriculture sectors such as pineapple cultivation and oil palm. Due to its geotechnical drawback
characteristics such as highly compressibility and low shear strength, peat soil is classified as problematic soils and
unstable for engineering structures. Lack of suitable and expensive price of lands, peatland will be an alternative
option for future development. Prior to construction works, stabilization of peat soil should be performed to enhance
its engineering characteristics. This paper presents the effect of cement and curing period on engineering properties
of the cement-treated peat soil. Some engineering variables were examined including the compaction behaviour,
permeability and unconfined compressive strength (UCS). The Atterberg limit test was also carried out to examine
the influence of cement addition on peat soil. The cement-treated peat soils were prepared by adding varying amount
of ordinary Portland cement (OPC) ranging between 0% and 40% of dry weight of peat soil. In order to examine the
effect of curing, the treated samples were dried at room temperature for three and seven days while for UCS tests
samples were extended to 28 days prior to testings. The results showed that the liquid limit of treated soil decreased
with the increase of cement content. Maximum dry density (MDD) increased while optimum moisture content (OMC)
dropped with the increase in cement content. Permeability of treated soil decreased from 6.2×10-4 to 2.4×10-4 ms-1 as
cement content increase from 0% to 40%. In contrast, the UCS tests indicated an increase in uncompressive strength
with the increase in cement contents and curing period. The liquid limit and permeability were also altered as curing
periods were extended from three to seven days. This study concluded that geotechnical properties of peat soil can
be stabilized using ordinary cement and by modification of the curing periods.