U.S. patent application number 13/028748 was filed with the patent office on 2011-06-09 for slurry compositions for ground improvement using blast-furnace slag cement and method of producing soil cement slurry by using same.
Invention is credited to Mitsuo Kinoshita, Takao Kono, Eiji Sato, Shinji Tamaki, Toshio Yonezawa, Tomonori Yoshida.
Application Number | 20110136946 13/028748 |
Document ID | / |
Family ID | 43308885 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110136946 |
Kind Code |
A1 |
Kono; Takao ; et
al. |
June 9, 2011 |
SLURRY COMPOSITIONS FOR GROUND IMPROVEMENT USING BLAST-FURNACE SLAG
CEMENT AND METHOD OF PRODUCING SOIL CEMENT SLURRY BY USING SAME
Abstract
Slurry composition for ground improvement is obtained from
cement, water and an admixture. The slurry composition cement is of
a kind prepared by using blast-furnace slag cement of a specified
type as the cement at a water/blast-furnace slag cement mass ratio
of 40-250% and contains the admixture in an amount of 0.1-5 mass
parts for 100 mass parts of the blast-furnace slag cement. The
blast-furnace slag cement of the specified type contains
blast-furnace slag fine particles with fineness 3000-13000
cm.sup.2/g in an amount of 60-80 mass % and portland cement in an
amount of 20-40 mass % for a total of 100 mass %.
Inventors: |
Kono; Takao; (Inzai, JP)
; Yonezawa; Toshio; (Inzai, JP) ; Sato; Eiji;
(Inzai, JP) ; Yoshida; Tomonori; (Inzai, JP)
; Kinoshita; Mitsuo; (Gamagori, JP) ; Tamaki;
Shinji; (Gamagori, JP) |
Family ID: |
43308885 |
Appl. No.: |
13/028748 |
Filed: |
February 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2010/059699 |
Jun 8, 2010 |
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13028748 |
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Current U.S.
Class: |
524/5 ;
106/714 |
Current CPC
Class: |
C04B 28/04 20130101;
C04B 2111/00732 20130101; C09K 17/10 20130101; C09K 17/40 20130101;
Y02W 30/91 20150501; C04B 28/04 20130101; C04B 18/141 20130101;
C04B 22/10 20130101; C04B 24/2664 20130101; C04B 24/32 20130101;
C04B 28/04 20130101; C04B 18/141 20130101; C04B 2103/14 20130101;
C04B 2103/30 20130101; C04B 2103/50 20130101; C04B 28/04 20130101;
C04B 18/141 20130101; C04B 22/10 20130101; C04B 24/2641 20130101;
C04B 24/32 20130101 |
Class at
Publication: |
524/5 ;
106/714 |
International
Class: |
C08K 3/00 20060101
C08K003/00; C04B 7/147 20060101 C04B007/147 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2009 |
JP |
2009-138002 |
Claims
1. A slurry composition for ground improvement, said slurry
composition comprising cement, water and an admixture, and being
prepared by using water and blast-furnace slag cement as said
cement at a water/blast-furnace slag cement mass ratio of 40-250%
and containing said admixture in an amount of 0.1-5 mass parts for
100 mass parts of said blast-furnace slag cement, said
blast-furnace slag cement comprising blast-furnace slag fine
particles with fineness 3000-13000 cm.sup.2/g in an amount of 60-80
mass % and portland cement in an amount of 20-40 mass % for a total
of 100 mass %.
2. The slurry composition for ground improvement of claim 1 wherein
said blast-furnace slag fine particles have fineness 3500-6500
cm.sup.2/g.
3. The slurry composition for ground improvement of claim 2 wherein
said portland cement is normal portland cement.
4. The slurry composition for ground improvement of claim 2 wherein
said blast-furnace slag cement comprises said blast-furnace slag
fine particles in an amount of 64-76 mass % and said portland
cement in an amount of 24-36 mass % for a total of 100 mass %.
5. The slurry composition for ground improvement of claim 4 wherein
said admixture at least partially includes a hardening accelerator
comprising an alkali metal carbonate salt.
6. The slurry composition for ground improvement of claim 5 wherein
said admixture at least partially includes a defoamer comprising
polyalkylene glycol monoalkenyl ether.
7. The slurry composition for ground improvement of claim 6 wherein
said admixture at least partially includes a fluidizer comprising
an alkali metal salt of water soluble vinyl copolymer obtained by
alkali hydrolysis of copolymer of .alpha.-olefin and anhydrous
maleic acid and having mass averaged molecular weight of
2000-70000.
8. The slurry composition for ground improvement of claim 6 wherein
said admixture at least partially includes a fluidizer comprising
an alkali metal salt of polyacrylic acid having mass averaged
molecular weight of 1500-50000.
9. The slurry composition for ground improvement of claim 7 wherein
water and said blast-furnace slag cement are used at a mass ratio
of 45-230%.
10. The slurry composition for ground improvement of claim 8
wherein water and said blast-furnace slag cement are used at a mass
ratio of 45-230%.
11. A method of preparing soil cement slurry, said method
comprising the step of using the slurry composition for ground
improvement of claim 9 in an amount of 300-1200 kg per 1 m.sup.3 of
ground.
12. A method of preparing soil cement slurry, said method
comprising the step of using the slurry composition for ground
improvement of claim 10 in an amount of 300-1200 kg per 1 m.sup.3
of ground.
Description
[0001] This application is a continuation of International
Application No. PCT/JP2010/059699, filed Jun. 8, 2010, priority
being claimed on Japanese Patent Application 2009-138002 filed Jun.
9, 2009.
BACKGROUND OF THE INVENTION
[0002] This invention relates to slurry compositions for ground
improvement using blast-furnace slag cement and a method of
producing soil cement slurry by using such slurry compositions.
[0003] In recent years, the demand for reducing the emission rate
of carbon dioxide and improving efficient energy consumption is
becoming increasingly stronger. Under this condition, blast-furnace
slag as by-product from steel mills is being effectively used as
material for blast-furnace slag cement in the form of blast-furnace
slag fine particles in mountain stationary construction,
underground water stop construction and soft ground improvement
construction works. Generally, when such a ground improvement work
is carried out, cement slurry with a mixture of cementatious
stabilizer and water (cement milk) is injected into the ground and
a drilling and kneading machine is used to mix and stir it with the
ground at the site, and blast-furnace slag cement is used here as
the cementatious stabilizer. Blast-furnace slag cement is usually
produced by mixing blast-furnace slag fine particles into normal
portland cement and is usually divided according to the JIS-RS211
standard into the following three kinds, depending on the amount of
the blast-furnace slag fine particles: Type A (over 5% to 30%),
Type B (over 30% to 60%) and Type C (over 60% to 70%). Type B with
a good balance in characteristics is usually used when actual
ground improvement is done.
[0004] For ground improvement, Type B blast-furnace slag cement is
normally mixed into 1 m.sup.3 of ground at a rate of 100-400 kg,
but since about 400 kg of carbon dioxide is emitted for producing 1
ton of Type B blast-furnace slag cement, this means that 40-160 kg
of carbon dioxide is emitted for improving 1 m.sup.3of ground by
using Type B blast-furnace slag cement, exclusive of the emission
of carbon dioxide generated by the operation of construction
machines, transportation of materials, etc. For this reason, in the
field of carrying out ground improvement, there have been demands
for the development of technology for suppressing the generation of
carbon dioxide by using blast-furnace slag cement at a higher rate,
while maintaining workability and the prerequisite that the ground
to be improved gain the necessary strength.
[0005] The present invention relates to slurry compositions for
ground improvement using blast-furnace slag cement that can respond
to such demands, as well as a method of producing soil cement
slurry using such compositions.
[0006] Regarding the effects of the conventional use of portland
cement for ground improvement, it has been reported, for example,
in "Manual for Ground Improvement by Cementatious Stabilizer"
(1984) pages 42-44, edited by the Cement Association of Japan, that
portland cement is alkaline because calcium hydroxide is generated
when it comes into contact with water and, if it is used for ground
improvement, the pH of the ground increases up to 10, adversely
affecting the growth of plants, etc. and that, if portland cement
is used for improving ground with low water content such as a loamy
layer, it becomes easier for hexavalent chromium in the portland
cement to elute, adversely affecting the environment. Besides the
above, there have been proposals for the improvement of fluidity of
cement slurry used for ground improvement such as those in Japanese
Patent Publications Tokkai 11-256161, 2000-169209 and 2006-298726,
as well as for hydraulic compositions using blast-furnace slag,
etc. usable also for ground improvement such as those in Japanese
Patent Publications Tokkai 62-158146, 63-2842, 1-208354, 10-114555
and 2002-241152, but there have been no detailed reports or
proposals contributing to the reduction in emission of carbon
dioxide.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of this invention to provide
slurry compositions for ground improvement capable of reducing the
generation of carbon dioxide by using blast-furnace slag cement at
a higher rate than being done at present such that the workability
of ground improvement work is maintained and the ground would gain
necessary strength, as well as a method of producing soil cement
slurry using such compositions.
[0008] The inventors herein have discovered as a result of their
diligent studies in view of the aforementioned object of the
present invention that slurry compositions for ground improvement
using together with an admixture a specified kind of blast-furnace
slag cement containing blast-furnace slag fine particles at a
higher rate and portland cement at a correspondingly lower rate, as
well as a method of producing soil cement slurry using such
compositions are correctly responsive to the object of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The present invention relates to slurry compositions for
ground improvement, comprising at least cement, water and an
admixture, the cement being blast-furnace slag cement comprising
blast-furnace fine particles with fineness 3000-13000 cm.sup.2/g in
an amount of 60-80 mass % and portland cement in an amount of 20-40
mass % so as to be together 100 mass %, the slurry compositions
being produced by mixing water with this blast-furnace slag cement
at a mass ratio of 40-250% and containing the admixture in an
amount of 0.1-5 mass parts per 100 mass parts of this blast-furnace
slag cement.
[0010] The present invention also relates to a method of producing
soil cement slurry characterized as using slurry compositions for
ground slurry using blast-furnace slag cement according to this
invention at a rate of 300-1200 kg per 1 m.sup.3 of ground.
[0011] A slurry composition for ground improvement using
blast-furnace slag cement (hereinafter referred to as a slurry
composition of this invention) is characterized as comprising at
least cement, water and an admixture. The slurry composition of
this invention uses blast-furnace slag cement of a special kind and
such blast-furnace slag cement is characterized as containing
blast-furnace slag fine particles with fineness 3000-13000
cm.sup.2/g in an amount of 60-80 mass % and portland cement in an
amount of 20-40 mass % such that their total would be 100 mass %
but those containing blast-furnace slag fine particles in an amount
of 64-76 mass % and portland cement in an amount of 24-36 mass %
such that their total would be 100 mass % are preferable.
[0012] Use is made of blast-furnace slag fine particles with
fineness in the range of 3000-13000 cm.sup.2/g but those with
fineness in the range of 3000-8000 cm.sup.2/g are preferable and
those with fineness in the range of 3500-6500 cm.sup.2/g are more
preferable. If those with fineness outside the range of 3000-13000
cm.sup.2/g are used, the fluidity of the prepared slurry
composition may be poor or the resultant ground strength may be
lowered. The fineness is herein expressed by the specific surface
area by the blain method.
[0013] Use as portland cement is usually made of normal portland
cement, high early strength portland cement or moderate heat
portland cement, but multi-purpose normal portland cement is
preferable.
[0014] For producing a slurry composition of this invention, the
mass ratio of water to blast-furnace slag cement is adjusted to
40-250%, and more preferably to 45-230%. If this mass ratio is
greater than 250%, the reduction in the ground strength becomes
great. If this mass ratio is less than 40%, on the other hand, the
fluidity of the soil cement slurry becomes too low. An admixture is
used in a slurry composition of this invention in an amount of
0.1-5 mass parts per 100 mass parts of the blast-furnace slag
cement. In the above, the mass ratio between water and
blast-furnace cement is the number obtained as ((mass of water
used)/(mass of blast-furnace cement used)).times.100.
[0015] Admixtures that may be used in the slurry compositions of
this invention include those used in conventionally known kinds of
soil cement. Examples of such admixture include fluidizers,
hardening accelerators and defoamers.
[0016] There is no particular limitation on the fluidizers to be
used but those comprising alkali metal salts of water soluble vinyl
copolymers obtained by alkali hydrolysis of copolymer between
.alpha.-olefin and anhydrous maleic acid and having mass averaged
molecular weight (throughout herein, pullulan converted weight by
gel-permeation chromatography method) of 2000-70000 are preferable
and those comprising alkali metal salts of water soluble vinyl
copolymers obtained by alkali hydrolysis of copolymer between
isobutylene and anhydrous maleic acid are particular
preferable.
[0017] Examples of preferable fluidizers further include those
comprising alkali metal salts of polyacrylic acid with mass
averaged molecular weight of 1500-50000 and they can be used in
combination with the aforementioned alkali metal salt of water
soluble vinyl copolymer. The amount of aforementioned fluidizers to
be used is preferably 0.1-4 mass parts to 100 mass parts of
blast-furnace slag cement, and more preferably 0.3-3 mass
parts.
[0018] Examples of hardening accelerator include alkali metal
carbonates such as sodium carbonate, potassium carbonate and
lithium carbonate. Among these, sodium carbonate is preferable from
economic reasons. These hardening accelerators are used for
improving the strength manifestation characteristic of the ground
hardener obtained by injecting a slurry composition of this
invention into ground, drilling and stirring. The amount of
hardening accelerator to be used is preferably 0.3-4 mass parts,
and more preferably 0.5-3 mass parts, for 100 mass parts of
blast-furnace slag cement.
[0019] There is no particular limitation on the defoamer to be used
but those of polyalkylene glycol monoalkenyl (or alkyl)ether,
modified polydimethyl siloxane and trialkyl phosphate can be
mentioned. For economic reasons and from the point of view of the
degree of manifestation of effects, however, defoamers comprising
polyalkylene glycol monoalkenyl ether are preferable. A defoamer is
used for eliminating the trouble of foaming when the slurry
composition of this invention is produced and also for controlling
the air to be dragged in when the slurry composition is injected
into the ground for drilling and stirring to thereby improve the
strength manifestation of the ground hardener. The amount of
defoamer to be used is preferably 0.001-0.1 mass parts, and more
preferably 0.002-0.01 mass parts, for 100 mass parts of
blast-furnace slag cement.
[0020] Slurry compositions of this invention can be prepared by a
known method. For example, they may be prepared by a method of
mixing specified amounts of blast-furnace slag cement, water and
admixture by placing them into a mixer and kneading them together.
At this moment, additive materials such as bentonite and fibers and
additive agents such as setting retarders and hardening
accelerators may be added, if necessary, within the limit of not
adversely affecting the effects of this invention.
[0021] In a method of fluidizing the soil cement slurry of this
invention, soil cement slurry is produced by mixing a slurry
composition of this invention described above with ground according
to the required fluidity of the soil cement slurry and strength of
the ground hardener. At this moment, the slurry composition of this
invention is used in an amount of 300-1200 kg, and preferably
400-1100 kg, per 1 m.sup.3 of ground.
[0022] The present invention has the effect of suppressing the
emission of carbon dioxide and controlling the lowering in fluidity
of prepared soil cement slurry with time by using blast-furnace
slag cement of a specified kind as a cement material together with
an admixture in ground improvement such that superior workability
can be maintained and the ground hardener can be allowed to
manifest necessary strength at the same time.
[0023] In what follows, the invention will be explained in terms of
some examples but these examples are not intended to limit the
scope of the invention. In the following examples, unless otherwise
explained, "%" means "mass %", and "parts" means "mass parts".
Part 1
Preparation of Fluidizer as Admixture
[0024] After water 145 g and 30% caustic soda 470 g were placed in
a flask equipped with a stirrer, copolymer of isobutylene and
anhydrous maleic acid (isobam 600 (tradename) produced by Kuraray)
395 g was gradually added with stirring while the internal
temperature was maintained at 60.degree. C. to obtain alkali metal
salt of copolymer by hydrolysis. This was analyzed by using GPC
(gel-permeation chromatography) method and found to be sodium salt
(p-1) of water soluble vinyl copolymer comprising sodium salt of
copolymer of isobutylene and anhydrous maleic acid and having mass
averaged molecular weight of 23000. By similar methods, fluidizers
(p-2) and (p-3) were prepared.
[0025] The fluidizers, hardening accelerators and defoamers used as
admixtures in this invention, inclusive of the fluidizers described
above, are shown together in Table 1.
TABLE-US-00001 TABLE 1 Type Details Fluidizer p-1 Sodium salt of
water soluble vinyl copolymer of isobutylene and anhydrous maleic
acid with mass averaged molecular weight = 23000 p-2 Potassium salt
of water soluble vinyl copolymer of isobutylene and anhydrous
maleic acid with mass averaged molecular weight = 65000 p-3 Sodium
salt of water soluble vinyl copolymer of diisobutylene and
anhydrous maleic acid with mass averaged molecular weight = 34000
p-4 Sodium salt of polyacrylic acid with mass averaged molecular
weight = 21000 p-5 Mixture of (p-1) and (p-4) at mass ratio of 2/1
Hardening c-1 Sodium carbonate accelerator c-2 Potassium carbonate
Defoamer d-1 Polyalkylene glycol monoalkenyl ether defoamer (AFK-2
(tradename) produced by Takemoto Yushi)
Part 2
Preparation of Blast-Furnace Slag Cement
[0026] Blast-furnace slag fine particles and portland cement were
used under the conditions shown in Table 2 to obtain blast-furnace
slag cement (S-1)-(S-4) and (R-1)-(R-3).
TABLE-US-00002 TABLE 2 Blast-furnace slag cement Mixture of
blast-furnace slag fine particles and portland cement (total of 100
mass parts) Blast-furnace slag fine particles Portland cement Type
Type Ratio (%) Type Ratio (%) S-1 sg-1 70 pc-1 30 S-2 sg-1 75 pc-1
25 S-3 sg-2 65 pc-1 35 S-4 sg-1 70 pc-2 30 R-1 sg-1 85 pc-1 15 R-2
sg-1 45 pc-1 55 R-3 sg-3 30 pc-1 70 In Table 2: sg-1: Blast-furnace
slag fine particles with fineness 4100 cm.sup.2/g sg-2:
Blast-furnace slag fine particles with fineness 5900 cm.sup.2/g
sg-3: Blast-furnace slag fine particles with fineness 1020
cm.sup.2/g pc-1: Normal portland cement pc-2: High early strength
portland cement
Part 3
Preparation of Slurry Compositions for Ground Improvement
Test Examples 1-8 and Comparison Examples 1-6
[0027] Specified amounts of blast-furnace slag cement shown in
Table 2 and kneading water (faucet water) were placed in a forced
mixing pan-type mixer under conditions shown in Table 3 and
specified amounts of fluidizer, hardening accelerator and defoamer
shown in Table 1 as admixtures were also placed inside to be
kneaded together to prepare each example of slurry composition for
ground improvement.
TABLE-US-00003 TABLE 3 Slurry compositions for ground improvement
Ratio of slurry composition (total = 100%) Mass ratio Blast- (%) of
furnace Admixtures water/blast- slag cement Water Fluidizer
Hardening Deformer furnace (type/used (used (type/used accelerator
(type/used slag cement amount amount amount (type/used amount Type
(%) (%)) (%)) (%)) amount (%)) (%)) TE-1 SL-1 200 S-1/33.3 66.7
p-1/0.4 c-1/2.5 d-1/0.005 TE-2 SL-2 200 S-2/33.3 66.7 p-2/0.4
c-1/2.5 d-1/0.005 TE-3 SL-3 200 S-3/33.3 66.7 p-3/0.4 c-1/2.5
d-1/0.005 TE-4 SL-4 200 S-1/33.3 66.7 p-4/0.4 c-2/2.5 d-1/0.005
TE-5 SL-5 100 S-1/50 50 p-5/1.8 c-1/1.5 d-1/0.003 TE-6 SL-6 100
S-3/50 50 p-1/1.8 c-2/1.5 d-1/0.003 TE-7 SL-7 50 S-2/66.7 33.3
p-1/2.5 c-1/1.0 d-1/0.002 TE-8 SL-8 50 S-4/66.7 33.3 p-1/2.5
c-2/1.0 d-1/0.002 CE-1 RSL-1 200 R-1/33.3 66.7 p-1/0.4 c-1/2.5
d-1/0.005 CE-2 RSL-2 200 R-2/33.3 66.7 p-2/0.4 c-1/2.5 d-1/0.005
CE-3 RSL-3 200 R-3/33.3 66.7 p-3/0.4 c-1/2.5 d-1/0.005 CE-4 RSL-4
100 S-1/50 50 -- -- -- CE-5 RSL-5 100 R-2/50 50 p-1/1.8 c-2/1.5
d-1/0.003 CE-6 RSL-6 200 S-1/33.3 66.7 p-1/0.4 c-1/0.05 d-1/0.005
CE-7 RSL-7 200 S-3/33.3 66.7 p-1/0.4 -- -- CE-8 RSL-8 200 *1/33.3
66.7 p-1/0.4 -- -- In Table 3: TE: Test Example CE: Comparison
Example Type of Blast-furnace slag cement: As described in Table 2
Types of fluidizers, hardening accelerators and defoamers: As
described in Table 1 Used amounts of fluidizers, hardening
accelerators and defoamers: Mass parts of solid component per 100
mass parts of blast-furnace slag cement *1: Type B blast-furnace
slag cement (density = 3.04 g/cm.sup.3; blain value = 3850
cm.sup.2/g)
Part 4
Preparation and Evaluation of Soil Cement Slurry
Test Examples 9-16 and Comparison Examples 7-12
[0028] Soil cement slurry was prepared by using each example of
slurry compositions for ground improvement prepared in Part 3 and
evaluated as follows. The injected amount of slurry compositions
for 1 m.sup.3 of ground improvement was determined such that the
target uni-axial compressive strength at material age of 28 days
would be over 5N/mm.sup.2. A specified amount of each slurry
composition for ground improvement prepared in Part 3 was firstly
placed in a hobart mixer and then ground with the physical
characteristics shown in Table 4 (mixture of cohesive soil obtained
by digging ground and silica sand at mass ratio of 3/1) was added
and mixed together to obtain the samples of soil cement slurry
shown in Table 5. Conditions for preparation of each sample are
also shown in Table 5.
TABLE-US-00004 TABLE 4 Mass per Particle density Fraction of
particles in volume Water content in mixed soil mixed soil (%)
(kg/m.sup.3) (%) (g/cm.sub.3) Cohesive soil Silica sand 1812 38.6
1.082 66.7 33.3
Evaluation of Physical Characteristics of Prepared Soil Cement
Slurry
[0029] For each example of soil cement slurry prepared, the flow
value immediately after the mixing with kneading, the flow value 90
minutes after the mixing with kneading, the air content and the
uni-axial compressive strength were obtained as follows and the
results are shown together in Table 5. Their emission rates of
carbon dioxide are also shown.
[0030] Flow values: Flow tests were carried out both immediately
and 90 minutes after the mixing with kneading and flow values after
elevation difference (mm) were measured 15 times according to
JIS-RS201.
[0031] Air content: Obtained according to JIS-A6201 (1977).
[0032] Uni-axial compression strength test: Compressive strength
(N/mm.sup.2) at material age of 28 days was measured on molded
articles obtained by using a mold with diameter 50 mm.times.height
100 mm according to JIS-A1108.
TABLE-US-00005 TABLE 5 Details of soil cement slurry Slurry
composition Content Evaluated physical characteristics for ground
of blast- Emmitted Flow value improvement Injection furnace amount
of (mm) Uni-axial Injected rate slag carbon 90 Air compressive
amount (volume cement dioxide Right minutes content strength Type
(kg) %) (kg) (kg) after later (%) (N/mm.sup.2) TE-9 SL-1 1031 80
344 82 226 214 0.6 6.0 TE-10 SL-2 1031 80 344 68 229 226 0.5 6.3
TE-11 SL-3 1031 80 344 96 221 207 0.5 6.4 TE-12 SL-4 1031 80 344 82
223 212 0.6 6.0 TE-13 SL-5 688 46 344 82 227 214 0.6 9.1 TE-14 SL-6
688 46 344 96 224 213 0.6 9.0 TE-15 SL-7 416 29 344 68 231 215 0.5
13.3 TE-16 SL-8 416 29 344 82 236 218 0.5 12.7 CE-9 RSL-1 1031 80
344 41 208 163 0.6 3.2 CE-10 RSL-2 1031 80 344 151 215 142 0.6 2.8
CE-11 RSL-3 1031 80 344 192 220 121 0.6 5.3 CE-12 RSL-4 1031 46 344
82 136 105 2.8 4.2 CE-13 RSL-5 1031 46 344 151 225 164 0.9 5.5
CE-14 RSL-6 1031 80 344 82 210 153 1.2 4.6 CE-15 RSL-7 1031 80 344
96 202 125 3.2 3.8 CE-16 RSL-8 1031 80 344 137 223 162 3.7 4.7 In
Table 5: Test Example Comparison Example Injected amount: Injected
amount (kg) of slurry composition for ground improvement per 1
m.sup.3 Injection rate: Rate of injection (volume %) of slurry
composition for ground improvement per 1 m.sup.3 Content of
blast-furnace slag cement: Content of blast-furnace slag cement
(kg) per 1 m.sup.3 Emitted amount of carbon dioxide: Amount of
carbon dioxide (kg) emitted for improving 1 m.sup.3 as calculated
from the amount of portland cement used
[0033] As can be understood from Table 5, each example of soil
cement slurry is characterized by a small amount of carbon dioxide
for improving 1 m.sup.3 of ground as compared with conventionally
used Comparison Example 16 which employs Type B blast-furnace slag
cement. Moreover, excellent fluidity and fluidity maintaining
characteristics with flow values less than 200 mm are obtainable,
and sufficiently satisfactory results in target uni-axial
compressive strength is attained.
* * * * *