11
50 PSI Grout for Medium
to Hard Soils
4 PSI Grout for Soft Soils
Amount
Ratio by
Weight
Amount
Ratio by
Weight
Water
30 gallons
2.5
75 gallons
6.6
Portland
Cement
94 lbs. (one sack)
1
94 lbs. (one sack)
1
Bentonite
25 lbs. (as required)
0.3
39 lbs. (as required)
0.4
NOTES:
The 28 day compressive strength of this mix
is about 50 psi, similar to very stiff to hard
clay. The modulus is about 10,000 psi
The 28 day strength of this
mix is about 4psi,
similar to very soft clay.
Table 1 - Cement/Bentonite/Water ratios
Add the measured amount of clean water to the barrel then gradually add the cement in the
correct weight ratio. Next add the bentonite powder, slowly, so clumps do not form. Keep adding
bentonite until the watery mix turns to an oily/slimy consistency. Let the grout thicken for
another five to ten minutes. Add more bentonite as required until it is a smooth, thick cream; like
pancake batter. It is now as heavy as it is feasible to pump.
When pumping grout (unless the tremie pipe is to be left in place,) withdraw the tremie pipe after
each batch, by an amount corresponding to the grout level in the borehole.
CAUTION: If the grout is pumped into the hole, rather than tremie piped, there is a danger that
the piezometer will be overranged and damaged. Pumping directly into the bottom of the
borehole should be avoided. It is good practice to read the piezometer while pumping.
For more details on grouting, refer to “Piezometers in Fully Grouted Boreholes” by Mikkelson
and Green, FMGM proceedings Oslo 2003. Copies are available from Geokon.
Содержание 4500AL
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