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Geotechnical News • March 2013
31
THE GROUT LINE
ened samples of dyed and un-dyed
grout. The dyed grout was easy to
differentiate from older grout. As an
example, Figure 3 shows a down-hole
camera image showing an intersected
hole containing dyed grout. Either
an old or new hole could have been
intersected; the dye allows differentia-
tion. The dyed grout was easier than
un-dyed grout to note in the gray rock
foundation. As an example, figure
4 shows a thin (less than 1/2-inch
tall) horizontal stringer of grout in a
downhole camera image. The dyed
grout helped protect the adjacent
trout hatchery from any damage; a
single release of dyed grout was eas-
ily detected (Figure 5) and grouting
was halted. The dye had no negative
effects on the physical properties of
the grout, as noted earlier.
Contractual discussion
Costs of dye injection mobilization
and demobilization were paid for by
lump sum, and grout was paid for
by dry weight. The authors would
discourage the use of dye ‘per gallon
of grout’ or ‘lump sum for the job’
as it may temp a contractor to gradu-
ally reduce the amount of dye used
unless the exact percentage of dye
is established by binding agreement.
Paying by the dry weight also allows
the owner the flexibility to increase
the concentration of dye if an espe-
cially bright batch of grout is desired.
Cost estimates for work with this
requirement should include costs for
mobilizing, installing, operating, and
demobilizing a dye injection system,
as well as the cost of the dye.
Potential uses for dyed grout
A number of uses for grout dye can
be determined, with a little imagina-
tion. Any time there could be a reason
to differentiate grouts, dye can be
utilized. The reason for the color dif-
ferentiation at Wolf Creek was to dis-
tinguish the current grouting campaign
from previous grouting campaigns.
Other ideas include dying different
series of holes (Primary, Second-
ary, Tertiary, etc.) each being dyed
a separate color. In multiple-line
grouting, each separate line could be
dyed a separate color. If two contrac-
tors are working on the same site, at
least one could be required to dye their
grout to differentiate their grouts. Low
Mobility Grout could be distinguished
from High Mobility Grout by use of
dye. Dye could be used on microfine
cement grouts to differentiate them
from coarser cement grouts, if both are
utilized on the same site. When grout-
ing a mass concrete structure, dyed
grout is potentially much easier to
identify than un-dyed cement grout.
No grouting job is too small for the
use of color. Quikrete produces single
ASTM C 979-complaint liquid dye
bottles, with each 10-ounch bottle
of dye reportedly coloring roughly
two bags of cement (Quikrete, 2012).
Figure 4. Dyed grout in downhole
camera image. The image shows
the entire circumference of the
hole. Horizontal lens of dyed grout
is from 46.05 to 46.10 feet (red
arrow). Depth interval of the image
is 44.02 to 48.92 feet. The white at
the top of the hole is a PVC casing.
Figure 5. Dyed grout coming out into the river. This was a single occurrence
and grouting was immediately stopped.