|
BLACK SOIL AND SOILS HIGH IN FINES.
In response to
many request on the expectations of soil improvements for Black
Soil (CBR of 2 to 3 with a Plastic Index of up to 60+) when
treated with ENDURAZYME EXPORT. At an application rate of one
litre to 35.5 M3, experience has shown that because
ENDURAZYME EXPORT takes a little time to reach full strength, it
may be necessary to modify the material to guarantee strength
under early trafficking. The following measures would be
suitable. Depending on the proportions of silts and clays it may
be necessary to change the application rate to 33.3 M3.
(1) Regardless of the excellent performance of ENDURAZYME EXPORT
it would be advisable to mix some gravels to improve the
grading, increase the density and load bearing capacity. The
addition of course fines, sand, and higher aggregates will
assist in providing further strength, so that particles have
some formation to interlock and bond with. These additions will
minimise maintenance schedules and lengthen the life of the
road. If no gravels are present in the mix, introduce 25% to
50%, if gravels are present; recycle with a maximum of 50/50%
Black Soil mix.
(2) Expected increase in CBR could be between 12 to 15.
The addition of 2% lime along with Endurazyme Export and
aggregate could show increases of up to 30 CBR. A saving of 50%
on lime stabilisation and the lime will not leach out
(3) ENDURAZYME EXPORT enables the soil to be worked dry of
optimum moisture content. If this is practised in the field,
there is a noticeable reduction in cracking and crazing. The
addition of some gravel will also have an effect of lowering the
soils overall P.I. and increase the structural strength of the
pavement, by tried and proven engineering principle.
A suggested specification would be: -
PERCENTAGE PASSING A.S.SIEVE TEST.
|
75.0
mm |
53.0
mm |
37.5
mm |
26.5
mm |
19.0
mm |
9.5
mm |
4.75
mm |
2.36
mm |
.425
mm |
.075
mm |
|
100% |
95%
to
100% |
85%
to
100% |
84%
to
91% |
70%
to
85% |
60%
to
80% |
30%
to
75% |
25%
to
60% |
10%
to
40% |
15%
to
50% |
Send us your soil
test results and we will send you a grading graph and
recommendations for a pavement suitable to your needs and the
application of "Endurazyme".
Having said all that, a ridge Gravel was used in the
construction of a very successful road, with a Plastic Index of
20 and a Liquid limit of 42.00. Below are the grading figures.
Documentation and location are available.
|
75.0
mm |
53.0
mm |
37.5
mm |
26.5
mm |
19.0
mm |
9.5
mm |
4.75
mm |
2.36
mm |
.425
mm |
.075
mm |
|
- |
- |
96.0 |
91.8 |
82.5 |
69.2 |
49.0 |
39.8 |
21.3 |
13.4 |
This is well below our recommendations on fines and was
specified by the engineer in charge. It worked and is still
working well.
Last but not least prior to any first application a soil
test is required so that if the soil does not fit into the
grading envelope a proportional mix design can be introduced.
(See
grading chart)
(See Rice husk ash and fine
clays)
By Brian Jackson
World Enzymes Australia
|
