Geo-parametric study of dredged marine clay with solidification for potential reuse as good engineering soil
Dredging is an essential process in the development, expansion and maintenance of ports, jetties and various water bodies. The process of removing sediments to create or maintain certain water depths inevitably produces large amounts of dredge materials. These displaced materials are generally soils...
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| Format: | Article |
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Springer-Verlag Berlin Heidelberg
2016
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| Online Access: | http://eprints.uthm.edu.my/8499/ |
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| Summary: | Dredging is an essential process in the development,
expansion and maintenance of ports, jetties and
various water bodies. The process of removing sediments
to create or maintain certain water depths inevitably produces
large amounts of dredge materials. These displaced
materials are generally soils of fine-grained nature, i.e.,
clay and silt size particles with limited usability due to low
strengths and high compressibility. Besides, exposure of
the sediments to contamination via the waterways has
made disposal of the material a much more regulated and
often costly practise, with uncertain risks of future detrimental
effects to the dump site’s surrounding environment.
It is therefore favourable to explore the reusability of the
dredged soils to minimise the need dumping. The present
study examines the reuse potential of a dredged marine
clay sample treated with induced solidification using binders
like cement and coal ash. A series of geo-parametric
measurements were performed on the material, including
the physical and chemical properties as well as the relevant
mechanical responses, i.e., strength and compressibility.
The dredged sample was prepared in dry powder form and
remoulded with an optimum water content to produce the
base soil for solidification. This was necessary to ensure
consistency of the water content in the soil for the various
batches of specimens prepared for the different tests. It was
found that the fundamental characteristics of the material
could be effectively improved with the addition of small
dosages of binders, as demonstrated by the filling of voids
and aggregates formation in the solidified soil. The
mechanical properties were also found to improve with
prolonged rest period, where over 100 % strength increment
and 60 % compressibility reduction were observed
after 28 days. Binder-wise, the coal ash was less potent
when used on its own and appeared to require activation by
the cement for solidification to take place. Indeed, the
blend of (3 % cement ? 7 % fly ash) and (5 %
cement + 5 % fly ash) produced the most significant
strength and compressibility improvement, respectively. In
short, corresponding results from the various tests conducted
provided a better understanding of the solidification
mechanism in the dredged marine clay sample for potential
implementation on site. |
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