Environmental Engineering Reference
In-Depth Information
Table 10.1
Relationship between soil moisture content and paper, high molecular weight polymer
and supplementary chemicals
Soil/water
ratio (%)
Water content
(%)
Amount of
paper debris
added (kg/m
3
)
High molecular weight
polymer added (Bon
Terrain P) (kg/m
3
)
Supplementary chem-
icals (Bon Terrain L)
added (kg/m
3
)
100
50.0
50
1.0
7.2
200
66.7
70
300
75.0
80
400
80.0
85
500
83.3
90
10.2.2
Amount of Paper Shredder Residue
In developing this process, the first matter which has to be established is to decide
the optimum amount of shredded paper and polymer additive. In particular, since it
is assumed that the effect of the shredded paper on the water content of the sludge
will be critical, various levels of water content in the sludge, amounts of shredded
paper and polymer additives, have been investigated to establish their effects on
the process, and on the handling and observed characteristics of the soil, its quality
and aggregate structure. The results of the changes in water content, paper shredder
residue, and quantity of additives and polymers are shown in Table
10.1
.
10.2.3
Fiber Strength Characteristics in the Soil Solidification
Process
In order to use treated soil as back fill and reclamation material, an understanding of
soil strength characteristics is essential. Therefore, we prepared a treated sample of
50 mm diameter and 100 mm height, and carried out compression tests (Mori et al.
2003
). The results are shown in Fig.
10.3
. In the case of solidification, increasing
the load also increases the compression strain, but the solid only shrinks by 1-2 %,
so the compressive stress increases to a maximum value up to the point of breakage.
In contrast, if the soil is solidified using fibers, the destructive distortion is 7-8 %
and, even after breakage the compressive stress is not reduced rapidly, and residual
strength also grows. In other words, the fibrous solidified waste soil, compared
with traditional cement solidification materials, provides a greater distortion before
breakage and higher residual strength, which is an important special feature.
Figure
10.4
shows the state of breakage in the samples after testing. A clear frac-
ture surface is seen in the solidified soil, which resembles the fracture shapes which
occur in rocks and concrete. In contrast, the fiber-solidified soil does not produce a
clear surface, and the sample as a whole grew in a so-called barrel-shaped deforma-
tion. This is because the inside includes fibrous substances so that soil particles and
fibers are intertwined in a complex manner, making destruction difficult because at
the same time the stress is distributed through the fibers.
