الفهرس 
REVIEW OF PREVIOUS STUDIESOnly 14 pages are availabe for public view
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Abstract
Grouting is one of the methods used to improve sandy soil properties. The
properties of the cement-based grouts depend on the injection pressure, bentonite
content, silica fume content, mixing method, viscosity of the grout, type of
curing water, and curing time. So the objective of the present study is to evaluate
the effect of the preceding parameters on the grout and grouted sand properties.
A laboratory grouting model is used to prepare the cement-based injected grout
samples. This model enables applying pressure up to 800 KN/m2. Two methods
for mixing cement-bentonite grouts are used; ”dry mixing” method and predispersion
of the cement addition to pre-hydrated bentonite which is referred to
as ”wet mixing”. The bentonite content ranges between zero and 60% and silica
fume content ranges between zero and 30%. The permeability coefficient is
determined for sand and grouted sand using a laboratory model after I, 7, and 28
days of grouting. The unconfined compressive strength is measured after 7 and
28 days of grouting. The tested sand is yellow silica medium sand. The cement
used is ordinary Portland cement. The results can be concluded as follows:
I. The grouted sand using cement-bentonite or cement-silica fume is considered
very low permeable soil (coefficient of permeability is less than 1*10-5
cm/sec.) 2. The unconfined compressive strength of the injected cement-bentonite grout
in sandy soil is constant regardless of the injection pressure for dry mixing
method, while there is an increase in the unconfined compressive strength
with the increase in the grouting pressure in case of using wet mixing.
3. The ratio between unconfined compressive strength of cement-bentonite
injected grout using dry mix and unconfined compressive strength of cementbentonite
injected grout using wet mix ranges between 1.25 and 7.5 for
bentonite content ranging between 10 and 60%.
4. The optimum content of silica-fume in cement-based grout equals 5% to
obtain maximum unconfined compressive strength. The unconfined
compressive strength of cement-silica fume grout in sandy soil after 28 days
equals 1.4 the unconfined compressive strength of cement-bentonite grout for
silica-fume content or bentonite content equals 5%.
5. The unconfined compressive strength of cement-silica fume injected and uninjected
grout after 7 days equals 80% of that after 28 days while this ratio
equals 60% for cement-bentonite injected grout.
6. The unconfined compressive strength of the injected cement-based grout in
sandy soil decreases as the bentonite content or silica fume increases.
7. The water content of the workable cement-based grout increases as the
bentonite content or silica fume content increases.
8. The unconfined compressive strength of cement-bentonite grouts cured using
salty water is greater than that for those cured using tap water by about 25 to
12% at 0 to 20% bentonite content respectively. The effect of salty water and
tap water is the same for bentonite content over 20%.