Nishi, Motohiro

Yamada, Masaru

Osaka City University Repository

Mem. Fac. Eng., Osaka City Univ., Vol. 43, pp.l05-109 (2002)
Granular Forming Treatment Test of Crushed Stone Sludge
and Soil Properties of The Granulated Soil
Motohiro NISHI* and Masaru YAMADA**
(Received September 30, 2002)
Synopsis
Crushed stone sludge is an industrial waste by-product of crushed stone and sand manufacture. In this study,
granular forming treatment tests of crushed stone sludge by an actual plant were conducted. The sludge mixed to
granulate with portland blast-furnace slag cement and polymer stabilizer agent. Sludge of moisture content 25, 50,
70, and 100% were tested. Sludges of moisture content 50 and 70% were possible to granulate, but cement
content increased. The granulated soils were tested for density and water absorption, grain size distribution, the
California bearing ratio (CBR), and permeability after curing for 63 days. The water absorption was high.
Therefore it has water retention capacity. With increasing cement content, the CBR values of compacted
specimens decreased, and the coefficient of permeability increased. They are caused by crushing with compaction
granulated soils which are low grain strengths.
KEYWORDS: Crushed stone sludge, Granulated soils, Soil properties, Grain strength
1. Introduction
Desiccation of aggregate used for concrete and asphalt mixture is a serious problem. Crushed stone and sand
are used instead of natural aggregate positively, and the use will increase year by year. But the production
generates crushed stone sludge.
Utilization of the sludge is impossible as is. Special treatments are necessary to utilize it. One of the treatment
methods includes granular forming treatment. The granulated soils are easy handling, and they are expected to
apply as construction materials. The granular forming treatment techniques of crushing after hardened by cement
and calcining by kiln after granular formed have been developed.1) 2) But the production process is many, and it
costs too much. This study adopted a system that granulates with mixing cement and polymer stabilizer agent to
sludges.3) The system is quite useful compared with the above system for production time and cost. Granular
forming treatment tests of crushed stone sludge by an actual plant and soil properties of the granulated soil are
reported.
•••• Supply of sludge
• •• Mixing of Blast-furnace slag cement
and polymer stabilizer agent
Blast-furnace slag cement
Polymer stabilizer agent
HORIZONTAL
ROTARY VALVE
LOWER
MIXINGCHAMBER ••• Mixing and granular forming
.'------,
--n-I-S-CHARGE I
I.. CRUSHER I~ ..·I Crush of grains and clods••. j (40mm under)-------~~;...•'
GRANULAR FORMING
TREATMENT PlANT
CRUSHED STONE SLUDGE
THRO~NGINOFSLUDGE
[ GRANUlATED SOIL )
Fig. 1 Production process of the granulated soils
* Research associate, Department of Urban Engineering
** Professor, Department of Urban Engineering
105
2. Experimental
Production process of the granulated soils is shown in Fig. 1. The tests were used Portland blast-furnace slag
cement and polymer stabilizer agent which polyacryamide coagulant is a main of. Properties of crushed stone
sludge are shown in Table 1. Sludges are mixed with cement and polymer stabilizer agent in mixing chamber of
the plant. It is granulated with crosslinked by polymer stabilizer agent and sheared by mixing. Mix proportion of
the granulated soil is shown in Table 2. The polymer stabilizer agent was added 2% of the cement by weight. The
granulated soils were investigated soil properties after curing for 63days.
Plasticity index 14.5
Liquid limit (%) 33.5
Plastic limit (%) 19.0
Moisture content (%) 25.0
390
330
70 420
650
50 380
500
Table 2 Mix Proportion of Granulated Soils
Moisture content (%) Cement content (kg/m3)
25 80
5.5
43.5Silt
Table 1 Properties of Crushed Stone Sludge
Grain Size distribution
Sand
Particle density (g/cm3) 2.747
Clay 51.0 100 300
3. Results and Discussion
3.1 Immediately after granular forming
The cone index of immediately after granular forming is shown in Fig. 2. And the photos are shown in photol.
The cone index of moisture. content 25% could not be determined. The cone index increased with increasing
cement content.
When the moisture content is 25%, cement stuck to only face of sludges. Because of low moisture content,
cement and sludges weren't mixed uniformly (photo l(a)). In case of the moisture content is 50% and 70%,
granulated soils were good shape (photo l(b)). It seems that the grain size became small with increasing cement
content. Sludge of moisture content 100% almost never granulated for too high moisture content and fluidity
(photo l(c)). Fluidities of moisture content 50% and 70% were also high, and cement was abundantly necessary to
granulate them.
() MOISTURE CONTENT 50%
o 70%
\7 100%
2000 ~-r--r--""T"".,...-,~~--r-~--r--r--r--r-.,...-,.~.,...-,.~'T--r''''''''
~ 1600,
z
~
'-' 1200
><
LU
C
z 800
LU
~ 400u
300 400 500 600 700
CEMENT CONTENT (kg/~)
Fig. 2 Cone Index of Immediately after Granular Forming
::·11Iill~;~!~:·:m:f;:~i: ;.:::: J~i@;:::~;;@
.kb,;.t~, . "'?"';;.~
(a) w=25%, SC=80kglm3 (b) w=70%, SC=420kglm3 (c) w=100%, SC=300kglm3
Photo 1 Granulated Soils of Immediately after Granular Forming
106
3.2 Soil properties of granulated soils
(1) Physical properties
The results of density and water absorption tests are shown in Table 3. The density was about 2.0glcm3• The
absorption was 25-30%. The granulated soils were material that is lighter and more retentive of water than crusher
run and sand.
The results of grain size distribution test are shown in Fig. 3. The grain-size accumulation curves moved to the
right side of sludge. The D50 decreased with increasing cement content. Cement and polymer stabilizer agent
contents vary the grain size distribution. Granular forming by adding low cement may be possible with increasing
polymer stabilizer agent.
Table 3 Density and Water Absorption of Granulated Soils
Moisture content (%)
330 1.92
Water absorption (%)
28.6
50 380 1.95 27.2
500 1.97 26.4
390 1.89 30.1
70 420 1.92 29.2
650 1.97 27.6
Crusher run 2.45--2.70 < 3.0
Sand 2.50--2.65 1.0--5.0
Symbol
o
Cement content (kg/~)
330
050
9.3
o 380 8. 7
4.3500
CRUS~ED STON
---,------- ---7-----
, ,20 -----------,- ----------: -----------;--
100 -~~~~===~~~~~~ft'TTTTT1
80
60
40
c..::J
z
en
en
<
0-
t-
Z
LU
U
0:::
LU
0-
ot........Jl..-.LJ...LW.L.L-...L...J..~~..-QI~~~J...U..L.U.JJ..----l.~~
0.001 0.01 O. 1 1 10 100
GRA INS I ZE (mm)
(a) Moisture Content 50%
Symbol
o
Cement content (kg/~)
390
050
12.5
o 420 10.2
6.0650
40 ---_. -----.'- ----------
I ,
60 -----------' ---------- ~ -----
'\l
100-~~~~==~=~~=~.,
80 C_R_~S_~~~ _~~~N __ ~~~~~~ _
, ,20 - -- - --- - - - -,- - --- -- -- -- + - - - - - - - - - - -:- - - - --
o 10 100O. 001 0.01 O. 1 1
GRAIN SIZE (mm)
(b) Moisture Content 70%
Fig. 3 Grain-Size Distribution Curve for Granulated Soils
c..::J
z
en
en
<
0-
t-
Z
UJ
U
0:::
UJ
0-
107
(2) Compaction .
The maximum dry densities and optimum moisture conten!s of granuJated sods ~~red for 63 da~s are show~d
in Table 4. The compaction methods used standard effort (Ec --:550kJ/m ) and modIfIed ~ffort (Ec:-2500kJ/m ).
The lightweight of granulated soils made maximum dry densities of low val~e. The op~Imum mOlstur~ contents
were showed approximately 30% due to high water absorption. As compactIve effort .In~reased, maxlmu~ dry
densities were up and optimum moisture contents were down, and it sho~ed resuI~s simll.ar to general soIls. It
appeared that granulated soils of low cement content compacted densely with crushIng grains. But the results of
moisture-density tests did not show recognizable difference.
Table 4 Maximum Dry Densities and Optimum Moisture Contents of Granulated Soils
Moisture
content
(%)
Cement Standard effort Modified effort
content Maximum dry Optimum moisture Maximum dry Optimum moisture
(kglm3) density (g/cm3) content (%) density (g/cm3) content (%)
330 1.227 34.8 1.411 31.8
50 380 1.283 32.7 1.483 29.5
500 1.250 34.5 1.434 31.2
390 1.124 33.0 1.374 32.0
70 420 1.115 31.1 1.302 32.0
650 1.190 33.5 1.405 31.4
(3) California bearing ratio
The CBR values of compacted specimens were measured after curing for three, seven, 28, and 91 days periods
with grained condition. The results of moisture content 70% are shown in Fig. 4. The CBR decreased with
increasing cement content, and changed br curing time. The CBR of cement content 650kglm3 didn't change. The
CBR of cement content 390 and 420kg/m increased up to seven days, but decreased beyond it.
The results are presented in Fig. 5, which shows the variations of CBR values versus compactions. The CBR
cement content 390kg/m3 increased markedly with increasing compactions.
The grains of cured for 3 or 7 days and low cement content are easy to crush by compaction, and it compacted
moderately. Therefore, it is considered that the CBR was gained high values. A Change of grain-size
accumulation curve of cement content 390kg/m3 was larger than cement content 650kg/m3 (Fig. 6). The
granulated soils of moisture content 70% were tested for modified CBR. The results are shown in Fig. 7. The
modified CBR was over 30%. The granulated soils may apply to subbase course as granular materials. But
examinations of durability are necessary to utilize as granular base course materials.
Symbol Cement content (kg/rrf)
0 390
0 420
"V 650
Symbol Cement content (kg/nr)
0 390
0 420
v 650
10020 40 60 80
COMPACTIONS (Blows per Layer)
Fig. 5 CBR-Compactions Relationship for Granulated
Soils (Compactions after curing for 63days periods)
1008020
100 100
80 80
~ 60 ~ 60
'-'
'-'
c:::: c::::~ 40 e 40
20 20 ij ~r-
40 60
CURING TIME (Days)
Fig. 4 CBR-Curing Time Relationship for Granulated
Soils (Curing with Grained Condition)
108
100
BEFORE
......... 80 • 390kg/m3 CEMENT~
'-' ~ 650kg/m3 CEMENT(.::J
z 60~ AFTER~
-< o 390kg/m3 CEMENT~
~ 40
v 650kg/m3 CEMENTzLLJ
u
a:::
LLJ 20~
OL...-J........L..L.U.QNlI=::=t::m:::~u.u...--L....J..J.....L.J.J.JW-.....J-..L..J...LWJJ
O. 01 O. 1 1 10 100
PARTICLE SIZE (mm)
Fig. 6 Grain-Size Accumulation Curve
Before and Mter Compactions
......... 60~
a:::
co
(..)
c 40
w
u.
c
~ 20
o...................--'--....I...-...a..-..I~ ...............a..-..........&.......I---.L.-L.......L.-....L...-'---1--L.-J
300 400 500 600 700
CEMENT CONTENT (kg/m 3)
Fig. 7 Modified CBR of Granulated Soils
-0
() STANDARD EFFORT (] MODIFIED EFFORT
\7 COMPACTION IMMEDIATELY AFTER
GRANULAR FORMING (MODIFIED EFFORT)
0--0--
>-S 10-2
(4) Permeability
Corresponding coefficients of permeability of cement contents are shown in Fig. 4. The grains were soft
immediately after granular forming treatment. The voids between them disappeared by compaction. The results
that compacted specimens were tested after curing for 63 days with compacted condition show that it is
impermeability most. Mter curing for 63 days with grained condition, they were compacted and tested for
permeability. Some hardened grains were crushed by compaction, but they were 10-2-10-3cm/s orders equal with
gravel and sand. When the compactive effort increased to 2500kJ/m3, grains were crushed more. Therefore, the
coefficients of permeability were 10-3-10-4 cm/s orders.
~ 100 ~r-r-~~~..,....,....,.....,....,.....,....,...,.....,...,......,..-.-,-~'"'I'""'T""T""'T"""f""'T"'""""""f""'T"'"""""....-r-,..
Q)
en
""~ 10-1
5 10-5
tt 10-6 ...........................................................-.......-...................................-&...............................-...............-................................
~ 300 350 400 450 500 550 600 650 700
U CEMENT CONTENT (kg/~)
Fig. 8 Coefficient of Permeability of granulated soils
4. Conclusions
This experiment produced the following results:
The moisture contents and the fluidities of sludge affected granular forming, such that sludge of low moisture
content was not miscible with cement and high moisture content was not granulated.
The granulated soils were material that is lighter and more retentive of water than crusher run and sand.
The amount used of cement and polymer stabilizer agent affected grain size distribution, such that the D50
decreased with increasing cement content.
The high CBR values were gained because the granulated soils at early ages and with low cement content
were compacted moderately with crushing grains.
The grain strengths affected the properties, such that CBR and permeability of compacted specimens.
References
1) Guideline for recycling of construction sludge, ACTEC, pp.49, 1999.
2) T. Kawachi, Y. Tokunaga, M. Kobayashi, K. Honma, Y. Tsukada, and Y. Ochiai: Utilization of calcined
material from construction waste, Journal of environmental systems and engineering, JSCE, No.643/Vll-14,
pp.21-27, February 2000. (in Japanese)
3) T. Suzuki, M. Ueda, K. Fujikawa, S. Ito: Granulated soil stabilization of high water contents, Proceedings of
the 4th Symposium on Ground Improvement, JSMS, pp.209-216, November 2000. (in Japanese)
109


Granular forming treatment test of Crushed stone sludge and Soil properties of the Granulated soil

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Granular forming treatment test of Crushed stone sludge and Soil properties of the Granulated soil

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