KALMATRON® KCRetyped Version of test from Gangotri Cement, India (No
changes were made to the spelling or wording of the original
document. An actual
copy of the original document is available on request.) We tested Kalmatron® in our cement and there was definitely some improvement in the properties. But the behaviour of the strength was rather strange. Our Normal Cement comprises of 40% of Clinker, 57% of Slag and 3% of Gypsum. We carried out three tests as under: In our
first test we added 0.5% of clinker to the above proposition
reducing the Slag proportion by 0.5%.
The result was slight improvement in strength. In our
second test we decreased the Clinker to 35%, Slag 61.5%, 3% Gypsum
and 0.5% Kalmatron®. The
result was more increase in Strength. In our
third test we decreased the Clinker to 30%, slag 66.5%, 3% Gypsum
and 0.5% Kalmatron®. The
result was that strength was too high. Under
Normal circumstances decrease in Clinker should lead to decrease in
Strength. Kindly
Justify the above results. Also
let us know is it possible for us to prepare cement according to our
third test. Will the
other properties remain same. What
will be the long term effect to the properties of the cement. As per
Indian Standard specification the Strength should be: 3 days
– 160, 7
days – 220,
28 days – 320 And
our result after adding Kalmatron® says 1.
40% Clinker 3
days – 180, 190
7 days – 340, 340 2.
35% Clinker
3 days – 200, 190
7 days - 380, 380 3.
30% Clinker
3 days – 240,
280 7 days – 430, 450 Hydration
and Oxidation of Indian Test Clinker Recently we received test results of Kalmatron® Cement (hereafter called KC) admixture to cement and feel it is necessary to analyze KC’s effect on the compressive strength obtained in the test. The recommended dosage of KC is
10 Kgs per 1000 Kgs of Portland Cement Type I; II.
For any cementitious mixes, we recommend a reduced amount of
water (at least 15% less) with a water to cement ratio (W/C) around
0.44. In the Indian Cement Plant test,
only 0.5% of KC was used, i.e. 5 Kgs of KC per 1000 Kgs of cement. The water to cement ratio (W/C) was 0.563.
The local Clinker showed a high sensitivity to KC with a
large amount of reactivity. Assuming
that this local cement contains aluminates and aluminoferrites, or
other metal containing micro-elements above known averages, we can
recognize and confirm the high performance of the lower KC
application. Metal
containing elements are chemically responsive to KC with direct
diffusion of oxygen and metals; i.e. oxidation reaction with
products of decay. For
cements that are poor or contaminated, Kalmatron provides for a
supplementary reaction to general hydration of cement.
Therefore, the hydration of the cement and oxidation of its
metal containing elements are consequent reactions, which results in
complete decay of the cement grain with a stronger and more
compacted cementitious structure.
A more complete hydration of all the cement grains is
achieved. For cements with advanced
mineralogy (but not because of gravimetric data) we are dealing with
an inverse or even parallel consequence of reactions.
Apparently, the less amount of Clinker, the higher the speed
(or shorter time) it takes for oxidation and the result is the
earlier appearance of the compressive strength.
Therefore, Kalmatron® KC provides early compressive strength
with a lowered amount of Clinker in the cement because of the active
reactivity with the dominating micro-metal elements of that
particular Portland Cement contained in the Indian Plant Cement
test. The mineralogical description of
the cement to be used in subsequent tests should be provided for the
purpose of evaluation to decide what the appropriate amount of
Kalmatron® KC is needed to gain the most benefits possible. Conclusion:
Kalmatron® KC can reduce the amount of Clinker needed in
Cement, while providing improved rheological results for the Cement. |
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