Annual Report,2009 - Directorate General of Mines Safety

DGMS Annual Report, 2009
parameters required for the Cement Capsule, it was decided that the following
parameters shall be essentially required for the Cement Capsules to be used in mines
as a Grouting materials.
Sr.
Parameters
Acceptable Limits
No.
1 Average of soaking time
3.0 (max)
(Minutes)
2 Initial setting time (Minutes) 3.0 (max)
3 Final setting time (Minutes) 15.0 (max)
4 Compressive Strength Gain
Minimum in MPa
after-
30 Minutes
4.5
2 Hrs
9.0
24 Hrs
16.0
7 Days
16.0
21 Days
16.0
28 Days
16.0
5 Anchorage Strength after
(Minimum in Tonnes)
30 Minutes
3.0 but test will be conducted till
2 Hrs
complete failure
5.0 but test will be conducted till
28 Hrs
complete failure
12.0 but test will be conducted till
complete failure
(b)
Chemical Properties of Cement Capsules
Sr.
No.
Chemical Test
Acceptable
Limits
1 Chloride Free
NIL
Chloride free cement capsule composition is essential
because, presence of chloride will exchange the
rusting rate of MS steel bolt grout with cement
capsules. This may lead to release the MS steel bolt
from the grouting material.
2 Viscosity/Thyrotrophic Nature of Wetted Cement
Capsules
35,000 to 50,000
cps.
Proper Viscosity and flow of wetted cement capsule is
necessary for proper grouting of the bolts. Viscosity of
wetted cement capsule should not be to less to flow
out of the hole and should not be too high to difficult
to insert the MS steel bolt. The optimum viscosity of
cement capsules will be in the range of 35,000 to
50,000 cps.
3 Shrinkage Test (IS:4031 (Part 10) 1988
Shrinkage of the grouted cement capsules should not
be more than 0.01% at 27 ± 2 0 C and 65% humidity Less than 0.01%
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