> Based on
> Swedish practice for cement stabilisation Ahnberg et al (Proc ICSMFE, New
> Delhi, 1994) says 4-13% for clayey silt, 6-16% for clay and 16-40% for
> organic clay. However, in Japan, Okamura (IS-Tokyo 1996) says that cement
> contents of 20-30% are common. For lime stabilisation it is common for the
> lime content to be less than 10%.
The above Swedish figures relate to dry mix method, while the Japanise
use wet mixing. The clays in Scandinavia have such a high in situ water
content (often greater than the liquid limit) that there is enough water
in situ for the chemical reactions (hydration, pozzolanic reactions
etc.), hence the powder can be mixed into the soil as dry. The soils
that are treated are usually somewhat sensitive (like the water content
exceeding liquid limit would generally indicate).
Japanese use wet mixing and add cement as a slurry. Then, to get any
benefits you need to use much higher cement content. The amounts you
would use in the lab very much depends on which method you want to
imitate.
When mixing cement into clays in lab, people usually mix the
powder/cement slurry into the clay with the food mixer. The end result
is very different from what is produced in the field where mixing is not
as controllsed. Hence, results from lab can never be applied directly to
field situations. Also, the chemical reactions are quite sensitive to
small changes in organic content etc. so with pure kaolin you will only
test reactions in pure kaolin.
Because of the problem of non-represenative lab samples people at
Helsinki University of Technology build a lab deep-mixing maschine
(scale 2:1 ...3:1)that produces columns in the same manner as in the
field. The triaxila samples are then cut off these columns.The clays
they use are natural undisturbed block samples. For more details please
ask me or contact them directly. Their contact info can be found by
following the links in http://scmep.civil.gla.ac.uk.
Regards,
Minna Karstunen
--
Dr Minna Karstunen
Lecturer in Geotechnical Engineering
University of Glasgow, Department of Civil Engineering,
Rankine Building (Oakfield Avenue), Glasgow G12 8LT, UK
Tel. +44 141 330 5208
Fax. +44 141 330 4557
Web-pages:
http://www.civil.gla.ac.uk/staff/mkarstunen.html
http://scmep.civil.gla.ac.uk
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