Environmental Engineering Reference
In-Depth Information
Table 18.6.
Chemical grouts - a summary of properties.
Typical viscosity
Grout type
Fluid behaviour
centipoise
Gel time
Stability
Examples
Comments
Sodium silicate
Newtonian
3-4 for
30-60 minutes
1) Undergoes syneresis
Joosten process
Non toxic and not an
initially, then
permeability
(loss of water and
environmental hazard.
Bingham
reduction
shrinkage on gelling).
Syneresis less of a problem in
10 for strength.
2) Unstable in alkaline
finer soils (sand and silt).
Viscosity
environment
Limit is fine-medium sand.
increases as
Krizak (1985) tests showed
grout gels
up to 10 or 100 times increase
in permeability with time
under high gradient seepage
Acrylamide
Newtonian
Less than 2
Gel time
Permanent
AM9 (now outdated
AM9 was one of the most
controlled
because of
popular grout for a long time.
by additives
neuro-toxicity).
Good permeability and
NaCl in
Injectite 80 (has
permanence. AM9 was
groundwater
higher viscosity)
replaced by methyl
may lessen
acrylamides, but the toxicity
gel time
of unreacted monomer remains
Phenoplast
Newtonian
1.5 to 3 initial
Gel time controlled
Permanent except under
Resorcinol
Medium toxicity. Geoseal
and constant until
by additives
alternating wet/dry
formaldehyde
2-10 centipoise used for dams
gel starts
conditions
NaOH e.g. Geoseal
at Worsley (Brett (1986))
Aminoplast
Newtonian
5, up to 10-20
Gel time controlled
Only gel in acid (pH
7)
Based on urea and
Toxic and corrosive prior to
with additives to
environment. Permanent
formaldehyde
gelling (acid catalyst)
stabilize gel time
except in wet/dry
conditions
Acrylate
Newtonian
2
Gel time controlled
Permanent
AC-400
Replaces AM9. Only 1% as
polymer
toxic. Krizek & Perez (1985)
tests showed it did not
deteriorate with time under
high (100) gradients.
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