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Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
6a) and respectively with a combination of Portland/eco-cement
(Table 6b).
Table 6a. The swell potential of the Bahlui clay stabilized with
Portland cement.
Bahlui clay with Normalized
area
n
A
Activity
coefficient
C
A
Swell
potential
0% CP*
5.198
0.578
high
2.5% CP*
5.162
0.571
medium
5% CP*
4.321
0.395
medium
7.5% CP*
3.756
0.277
Medium
10% CP*
3.185
0.157
low
(* ) Portland cement
Table 6b. The swell potential of the Bahlui clay stabilized with
Portland and eco-cement
Bahlui clay with Normalized
area
n
A
Activity
coefficient
C
A
Swell
potential
0% cement*
5.198
0.578
high
2.5% cement*
4.729
0.48
medium
5% cement*
4.109
0.35
medium
7.5% cement*
3.983
0.324
medium
10% cement*
3.272
0.175
low
(* ) Portland and eco-cement with 50% participation each
The chart of the stabilized Bahlui clay has been plotted for
each cement percentage used in the mix (Portland and eco-
cement) using the results obtained from the granulometric
analyses and plasticity limits determination (Figure 5).
10 20 30 40 50 60 70 80 90 100
10
20
30
40
50
60
80
90
70
100
1.00
0.1
0.01
0.001
0.005
0.05
2
0.25
0.5
10 20 30 40 50 60 70 80 90 100
Illites
Montmorillonites
Kaolinate
0.002
Activity=1.0
Activity=0.5
U - line
A - line
Figure 5. The chart of the Bahlui clay stabilized with various percentage
of cement mix (50% Portland cement and 50% eco-cement).
It can be noticed, based on the analysis of the data from
Tables 6a and 6b:
- the reduction of the swell potential along with the
Portland cement increase;
- the ecologic cement presents a smaller influence than
the Portland cement.
4 CONCLUSIONS.
The comparative analysis on the evaluation of the swell
potential of the London, Hubbali, Ankara and Bahlui-Romania
clays confirmed, as presented in previous publications, that the
use of only two indices I
P
, w
L
or A
2µ
, may lead to different
classifications of the swell potential of active clays.
The assemblage in one representation of the Skempton-Van
Der Mewe diagram, the Casagrande-Chleborad diagram and the
granulometric curve has made possible the plotting of a specific
soil “print” for each soil. On its basis, a “unifying” coefficient
has been defined C
A
, namely the soil’s activity coefficient.
Thus, active soils can display a low, medium, high and very
high swell potential.
This coefficient was also utilized to study the influence of
the Portland and ecologic cement stabilization on the swell
potential of the Bahlui clay from Romania. Stabilization with
the Portland or the ecologic cement presents a decrease of this
potential from high to low, along with the increase of the
cement participation from 2.5% to 10%.
The eco-cement is not providing a significant decrease of
the swell potential by comparison with the Portland cement, but
it reduces the environment pollution during the manufacturing
process.
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