Conference PaperPDF Available

SELF-COMPACTING CONCRETE IN JAPAN

Authors:

Abstract and Figures

State-of-the-art technology in the applications of self-compacting concrete (SCC) in Japan for the last ten years are described. SCC is defined in terms of the common scale for the workability of fresh concrete by the Japan Society of Civil Engineers. Technologies of cementitous materials and chemical admixtures for achieving SCC are described against high cement content and low water to cement ratio in SCC. Also, another technological development for promoting SCC is described. Applications of SCC for practical structures are summarized for each case.
Content may be subject to copyright.
SELF-COMPACTING CONCRETE IN JAPAN
Masahiro OUCHI
Associate Professor, Kochi University of Technology, Japan.
Etsuo SAKAI
Professor, Tokyo Institute of Technology, Japan.
Tomomi SUGIYAMA
Manager, BASF Pozzolyth, Japan.
Kenrou MITSUI
General Manager, Takenaka Corporation, Japan.
Tekefumi SHINDO
Executive Chief Research Engineer, Taisei Corporation, Japan.
Koichi MAEKAWA
Professor, The University of Tokyo, Japan.
Takafumi NOGUCHI
Associate Professor, The University of Tokyo, Japan.
ABSTRACT:
State-of-the-art technology in the applications of self-compacting concrete (SCC) in Japan for the last ten
years are described. SCC is defined in terms of the common scale for the workability of fresh concrete by
the Japan Society of Civil Engineers. Technologies of cementitous materials and chemical admixtures for
achieving SCC are described against high cement content and low water to cement ratio in SCC. Also,
another technological development for promoting SCC is described. Applications of SCC for practical
structures are summarized for each case.
Keywords: self-compacting concrete, self-compactability, mix-proportioning, cement, superplaticizer,
quality assurance, application, design, construction, steel-concrete composite, concrete products, cost
1. WHAT IS SELF-COMPACTING CONCRETE?
1.1 SCC in Terms of the Common Scale for
Workability of Fresh Concrete
The Japan Society of Civil Engineers established
“Recommendations for Mix Design of Fresh Concrete
and Construction Placement related the Evaluation
Performance” in 2007, in which the concept for unified
evaluation for the workability of fresh concrete [1].
Here, workability means the degree of compaction of
fresh concrete into the formwork and it was defined as
the combination or balance between the flowability and
the resistance to the segregation.
This concept is applicable to both conventional
concrete and self-compacting concrete (SCC). In this
concept, the scale of the slump value is common. The
only difference between conventional concrete and
SCC is the necessity for the vibrating compaction to
obtain the slump value in the scale. That is why
self-compactability of fresh concrete can be described
quantitatively in the common scale for conventional
concrete.
Fig. 1 SCC and conventional concrete along the
common scale for workability
The resistance to segregation of SCC is higher due to
its higher unit powder content than that of conventional
LargeSmall Slump flow value
Good
Poor
Performance
Resistance to
segregation
Flowability
Requirement of workability
for the structure
Conventional
SCC
LargeSmall Slump flow value
Good
Poor
Performance
Resistance to
segregation
Flowability
Requirement of workability
for the structure
Conventional
SCC
72
Keynote Lecture 3
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
concrete and that results in the wider range for the
slump value for effective compaction of fresh concrete
in the structure (Fig. 1).
1.2 Methods for Achieving Self-Compactability of
Fresh Concrete
The method for achieving self-compactability involves
not only high deformability of paste or mortar, but also
resistance to segregation between coarse aggregate and
mortar when the concrete flows through the confined
zone of reinforcing bars. Okamura and Ozawa have
employed the following methods to achieve
self-compactability (Fig. 2)[2]:
(1) Limited aggregate content
(2) Low water to powder (cement) ratio
(3) Use of superplasticizer (HRWRA: High Range
Water Reducing Admixture)
Fig. 2 Methods for achieving self-compactability
The frequency of collision and contact between
aggregate particles can increase as the relative distance
between the particles decreases and then internal stress
can increase when concrete is deformed, particularly
near obstacles. It has been revealed that the energy
required for flowing is consumed by the increased
internal stress, resulting in blockage of aggregate
particles. Limiting the coarse aggregate content,
whose energy consumption is particularly intense, to a
level lower than normal proportions is effective in
avoiding this kind of blockage.
Highly viscous paste is also required to avoid the
blockage of coarse aggregate when concrete flows
through obstacles. When concrete is deformed, paste
with a high viscosity also prevents localized increases
in the internal stress due to the approach of coarse
aggregate particles. High deformability can be achieved
only by the employment of a superplasticizer, keeping
the water-powder ratio to be very low value.
2. TECHNOLOGY FOR THE
SELF-COMPACTABILITY OF FRESH
CONCRETE MATERIALS AND ITS PROMOTION
2.1 Introduction
The main characteristic in the mix-proportioning of
self-compacting concrete is large cement content and
low water to cement or powder ratio (Fig. 3). Both
the low water to cement or powder ratio and high
deformability of SCC at the fresh stage can be
compatible with a high dosage of superplasticizer.
These can be achieved by the material as the cement
and superplasticizer have been newly developed to
meet the requirements for SCC [2]. In this chapter,
the technologies of the materials for SCC, that is,
cementitous materials and superplasticizer for SCC are
described.
Also, the technological development for SCC is
described in “Recommendation for Construction of
Self-Compacting Concrete” by the Japan Society of
Civil Engineers (JSCE) in 1998 to promote the use of
SCC as the standard concrete rather than a special one.
Fig. 3 Large cement content and low water to
cement or powder ratio in SCC
2.2 Cementitous Materials
2.2.1 Cement
Many researchers have studied and reported on the
effects of cement properties on the fluidity of cement
pastes with superplasticizers and the effect of molecular
structure of superplasticizers [3][4][5]. The C3A, SO3,
gypsum hemihydrate and soluble alkali content, as well
as the fineness and specific surface area of the hydrated
cement paste, have all been cited as cement qualities
that affect the performance of the superplasticizer.
C3A content is the main factor in the control of the
fluidity of cement pastes with superplasticizers.
Yamada et al. studied cement with a C3A content of 5.3
to 7.3% and an alkali content, K2O in particular, of not
less than 1%. The results of this study showed that
alkalis, particularly K2O, in C3A increase the reactivity
and decrease the fluidity of cement pastes and that the
ratio of the SO3 content to that of Na2O in the clinker is
an important factor [6]. The relationship between the
C3A content of the cement and the apparent viscosity of
the cement pastes prepared by industrial plants in Japan
is shown (Fig. 4) [7]. The apparent viscosity varied
greatly for C3A contents greater than about 8%
irrespective of the type of superplasticizer;
polycarboxylate based superplasticizer (PC34) or
naphthalene based superplasticizer (BNS). Particularly
noticeable was the large variation in apparent viscosity
when the dosage of BNS was smaller. In contrast, for
C3A contents below about 8%, the apparent viscosity
was constant regardless of the type and dosage of
superplasticizer.
0 20 40 60 80 100
Volume(%)
Coarse
Coarse
aggregate
aggregate
Fine
Fine
aggregate
aggregate
Cement
Cement
or Powder
or Powder
Water
Air
RCC
for
Dam
Normal
SCC
0 20 40 60 80 100
Volume(%)
Coarse
Coarse
aggregate
aggregate
Fine
Fine
aggregate
aggregate
Cement
Cement
or Powder
or Powder
Water
Air
RCC
for
Dam
Normal
SCC
Self-Compactability
High Deformability
Limited Aggregate Content
Effect of
Superplasticizer
Low Water-Powder Ratio
compatible
High Segregation
-Resistance
73
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
Fig.4 Influence of C3A contents on the fluidity of
cement paste with superplasticizers
Portland cement with a C3A content of less than 5%,
such as low heat Portland cement and moderate heat
Portland cement, is very useful for the production of
high durable concrete and self compacting concrete.
The typical mineral composition calculated by using
Boug’s equation for low heat and moderate heat
Portland cement compared with ordinary Portland
cement is shown (Tabl e 1 ).
Table 1 Mineral composition of Portland cement
Typ e C 3SC2S C
3A C4AF
Ordinary
Moderateheat
Low heat
51 25 9 9
43 35 5 12
27 58 2 8
(%)
On the other hand, raw materials originating from
waste have recently come to be used as ingredients in
the manufacturing of cement. The Advisory committee
of the Ministry of Economy, Trade and Industry has
proposed that the cement industry should adjust the
amount of the waste utilization to 400 kg/ton for the
formation of the closed-loop materials-cycle society in
2010 [8]. This target value was already reached in
2007. The waste in common use contains a higher
proportion of Al2O3 (the aluminate phase) than ordinary
Portland cement (OPC) as shown in Fig. 5 [9]. With
little prospect of major increases in conventional
cement production in the future and with pressure on
the cement industry to contribute to sustainability, it is
very likely that cement with more of this aluminate
phase will have to be used.
Fig. 5 Chemical composition of wastes and
by-products as raw-materials of cement
Eco-cement that uses 500 kg/ton or more of waste such
as incineration ash of municipal refuse and sludge per
cement ton is presently being manufactured in Japan.
The JIS for eco-cement was established in 2003. The
amount of C3A in this cement is about 14%, a large
value compared with the 8a9% of ordinary Portland
cement (OPC).The dosage of superplasticizer for
which eco-cement paste achieves the same viscosity is
large compared with that for OPC [10]. When the
apparent viscosity was 350 mPas, the dosage of P-34
is 1.13 times the normal value in eco-cement. For the
dosage of S-34 for eco-cement, 1.5 times the value of
that for OPC is needed. The dosage of naphthalene
based superplasticizer for OPC and eco-cement is 1.5
times and about 4.3 times respectively, the dosage of
P-34. The relationship between the apparent viscosity
of eco-cement pastes and the adsorption of
superplasticizers per specific surface area is shown (Fig.
6). The amount absorbed and the thickness of the
adsorption of Polycarboxylate based superplasticizer
(P-34 or S-34) on the surface of hydrated cement tend
to be dispersion forces.
8000
0
1000
2000
3000
4000
5000
6000
7000
0123
Adsorption of polymer /mgm
-2
Apparent viscosity/mPas
䂺㱎-NSEC)
䂹㱎-NSOPC)
S-34EC)
S-34OPC)
P-34EC)
P-34OPC)
8000
0
1000
2000
3000
4000
5000
6000
7000
0123
Adsorption of polymer /mgm
-2
Apparent viscosity/mPas
䂺㱎-NSEC)
䂹㱎-NSOPC)
S-34EC)
S-34OPC)
P-34EC)
P-34OPC)
8000
0
1000
2000
3000
4000
5000
6000
7000
0123
Adsorption of polymer /mgm
-2
Apparent viscosity/mPas
䂺㱎-NSEC)
䂹㱎-NSOPC)
S-34EC)
S-34OPC)
P-34EC)
P-34OPC)
0
1000
2000
3000
4000
5000
6000
7000
0123
Adsorption of polymer /mgm
-2
Apparent viscosity/mPas
䂺㱎-NSEC)
䂹㱎-NSOPC)
S-34EC)
S-34OPC)
P-34EC)
P-34OPC)
Fig. 6 Relation between the apparent viscosity of
cement pastes and the adsorbed amounts of
superplasticizers per surface area(EC: Eco-cement,
OPC: ordinary Portland cement, P-34polycarboxylate
based, S-34: polycarboxylate containing SO3group
based, E-NS: naphthalene based)
On the other hand, an electrostatic repulsion force is
provided by the adsorption of naphthalene based
superplasticizer (E-NS) on the surface of hydrated
cement; consequently, the fluidity of cement paste can
be improved by adsorption of superplasticizers on the
surface of hydrated cement. If the amount of
superplasticizers absorbed on the surface of hydrated
cement is the same, the fluidity of cement paste with
superplasticizers becomes the same. Superplasticizers
stored as hydrates cannot disperse cement particles.
With the same superplasticizer, if the absorbed amount
per unit surface area is the same, the viscosity of the
paste must be equal. The reason for the difference of
the amount absorbed that shows the same viscosity as
for pastes is that superplasticizers are stored and this
depends on the amount of aluminate in the cement.
When eco-cement containing 13.7% C3A is used, the
absorbed or stored amounts of superplasticizers
74
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
increases compared with the case of OPC containing
8.8% C3A content. Molecular structure influences the
amount of absorption of the hydrates of
superplasticizers. Large superplasticizers, such as P-34
or S-34, are not easily absorbed by hydrates.
The paste fluidity of cement containing high C3A
content can be improved by using of mineral
admixtures such as granulated blast furnace slag, fly
ash and limestone powder. Fig. 8 shows the influence
of granulated blast furnace slag on the fluidity of
cement paste containing 12% C3A [11]. The Fineness of
granulated blast furnace slag is 4,000 cm2/g. The C3A
content of cement is related to the paste fluidity of
cement containing 12% C3A with granulated blast
furnace slag. The fluidity of cement paste containing
12% aluminate phase is improved by adding granulated
blast furnace slag with more than 20% mass. In this
case, the dilution of the C3A content of cement is
mainly effected by adding granulated blast furnace slag.
The addition of limestone powder is very useful for the
improvement of the fluidity of paste with cement
containing 12% C3A with polycarboxylate based
superplasticizer. When the replacement ratio of
limestone powder is 10% to cement, containing 12%
C3A, the fluidity of the cement paste is the same as the
fluidity of cement containing 9% C3A. The early
hydration of cement is retarded by the addition of
limestone powder. In this case, the retardation effect of
very early hydration of cement, by adding lime stone
powder, is also an important act in the addition of the
dilution effect [12].
Blended cement containing high C3A content is very
useful for the counter measure of sustainable
development in society and the reduction of CO2. The
material design for cement for high durable and
self-compacting concrete is also necessary for all
aspects of sustainable development in society.
2.2.2 Mineral Admixtures
(1) Introduction
In Japan, JIS for BFS, Fly ash, expansive additives,
silica fume are established. In addition, granulated
slowly cooled blast furnace slag, limestone powder and
the ettringite based additives such as high strength or
quick setting or rapid hardening additives are used in
Japan. BFS, Fly ash, expansive additives, silica fume
and limestone powder are useful for the production of
high durable concrete and self compacting concrete.
The main components and the action mechanisms of
mineral admixtures are shown (Fig. 7).
Of them, the applications of limestone powder and
granulated slowly cooled blast furnance slag to SCC are
described here in terms of self-compactability of fresh
concrete.
Fig. 7 Action mechanisms and main components of
mineral admixtures
(2) Limestone powder
Limestone powder is widely used for the production of
self compacting concrete. Table 2 shows the quality
standards of limestone powder (a draft) proposed by the
technical committee of JCI [13]. The standards were
made based on the test results obtained from common
samples with different specific surface areas and
limestone powder of various kinds. This standard is
prescribed for the quality control of limestone powder
used in admixture for mortar or concrete. Limestone
powder prescribed in this standard is defined as
“limestone powder is ground limestone having CaCO3
(calcite) as a main component and it is not regarded as a
binder, though it is not chemically inert powder.” It is
reported that the limestone powder reacts with various
kinds of calcium aluminate and accelerates the
hydration of alite. Different from granulated
blastfurnace slag and fly ash, though the early strength
of concrete was increased by the addition of limestone
powder, it does not contribute to the development of
long term strength. Therefore in this quality standard,
limestone powder is regarded as a non-binder.
It is possible to apply this standard to the limestone
powder used in the filler cement as an admixture, where
a cement producing method is adopted to mix the
prepared limestone powder in Portland cement.
However, in the production of filler cement it is
accepted that clinker, gypsum and limestone are ground
together. At present, since there is almost no available
data for this process, we are expecting the accumulation
of such data in the future. So, the technical committee
at this time decided to exclude the standards for filler
cement.
Since limestone powder is regarded as a non-binder, the
specific surface area has no need to be confined within
the scope of this standard unless it exerts harmful.
However, the same value as for normal Portland cement
is prescribed. In the case of high flowing concrete, it is
necessary that the fineness of limestone powder is the
same as for Portland cement in order to prevent the
bleeding and segregation of concrete. Limestone
powder has properties which prevent an increase in the
75
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
heat of hydration, and furthermore it is necessary to
distinguish limestone powder from fine aggregate.
Our technical committee decided not to regard the
limestone powder as a binder. Under the fixed water
cement ratio, if the limestone powder mixed with
cement shows no bad influence, it is accepted. The
compressive strength ratio of not less than 100% was
applied. The replacement ratio {limestone
powder/powder (cement + limestone powder)} of test
mortar by limestone powder was set at 25% and the
water to cement ratio was set at the same value as
standard mortar. In the tests of this time, limestone
powder with small CaCO3 content of about 50% did not
lower the compressive strength. 95% may be accepted
for the total amount of CaCO3 and MgCO3. Analysis
of Japanese limestone shows that almost all the
limestone has CaCO3 content in excess of 95%.
Therefore in Japan the described value may be
comparatively easily satisfied under the condition that
surface soil is kept from mixing in. The prescribed
value is important to avoid mixing in of surface soil.
As is shown in Tab l e 2 , the amounts of adsorbed
methylene blue on limestone powder are increased with
the decrease of the contents of CaCO3 in limestone
powder. Further addition of material with lesser
quantities of CaCO3 results in the lowering of the flow
value of mortar. Therefore we decided to set the lower
permissible limit for the quantity of CaCO3.
Table 2 Quality standard for limestone powder
(draft)
Note (1) Limestone powder purity was 90%. MgO
was mainly originated from MgCO3 contained in
limestone powder. If the remaining 10% is MgCO3,
MgO becomes 5% or less. In the case where it is
supposed that something other than MgCO3 is
contained in the limestone powder, it should be
confirmed before the use of limestone powder that
the material has no bad influence upon the
properties of concrete.
Note (2) As for S, confirm that it is not present in
the FeS form. Futher,since there are cases where
limestone powder is used in large qauntities,
quality standards for limestone powder were made
more rigorous than for cement, basing on the
results of chemical analysis of the samples
collected for the test of this time.
Note (3) It is prescribed, considering the mixing in
of impurities such as clays.
Note (4) Although no prescribed value for the
content of organic matter is defined, the total
organic carbone analysis should be applied to the
case where mixing in of a large quantity of organic
matter is supposed.
Note(5) Density: Though no prescribed value is
defined, it should be reported under the necessity
for the adjustment of mix proportion.
Quantities of alumina and absorbed methylene blue are
determined respectively as the indicator of mixed in
clay components. Since the absorbed amount of
methylene blue has a close relationship with quantities
of CaCO3 and alumina, it can be estimated from the
results of a chemical analysis. In the case where this
value is higher than the standard value, it shows great
possibility of having harmful effects on the properties
of concrete. This criterion is also useful as an index to
judge the property of the adsorbed amount of chemical
admixture or the reduction of air entraining activity of
such admixture as air entraining (AE) agent, AE water
reducing agent and AEHRW.
Since limestone powder is used to improve the fluidity
of concrete or to prevent the segregation of high
flowable concrete, it is desirable to define the standard
of requirements of fluidity or workability for limestone
powder such as the flow value ratio. However, due to
the lack of suitable standard AE high range water
reducing agent (AEHRW), flow tests carried out
without the addition of AEHRWA will produce
disadvantageous results for fine limestone powder.
Limestone powder with lesser quantities of CaCO3
produces mortar with low fluidity, showing a
correlation between the quantity of CaCO3 in limestone
powder and the fluidity of mortar. Therefore we
decided not to prescribe such standard values for
fluidity.
The relation between the spherical factor (packing bulk
density/specific gravity) of inorganic powders and the
fluidity of cement paste with prepared inorganic
powders is shown (Fig. 8) [14]. In the measurement
of the fluidity of paste, the replacement ratio of
prepared inorganic powders is 40% and the water to
powder ratio is 0.9% volume. By using powders which
have higher spherical factor, the fluidity of paste can be
improved. The spherical factor of particles is related
to the shape of particles. The spherical factor of PLS
is larger than that of PFA and PBFS. Though the shape
of PFA is spherical, the spherical factor of PFA is lower
than that of PLS. This is attributed to the contents of
carbon. It was reported that the contents of carbon
having an irregular shape in PFA is determined by the
fluidity of cement paste with PFA. The spherical
factor of powders is one of the main factors considered
in order to improve the fluidity of cement paste with
inorganic powders. The spherical factor of powders is
d1.0
Amounts of adsorbed
Methylene Blue (mg/g)
d1.0
Moisture contents (%)
d1.0
Al
2
O
3(3)
(%)
d0.5
SO
3(2)
(%)
d5.0
MgO
(1)
(%)
t90
CaCO
3
(%)
t100
28 days
t100
7 daysRatio of
compressive
Strength %
t2,500
Specific surface area
(cm
2
/g)
RequirementsItems
d1.0
Amounts of adsorbed
Methylene Blue (mg/g)
d1.0
Moisture contents (%)
d1.0
Al
2
O
3(3)
(%)
d0.5
SO
3(2)
(%)
d5.0
MgO
(1)
(%)
t90
CaCO
3
(%)
t100
28 days
t100
7 daysRatio of
compressive
Strength %
t2,500
Specific surface area
(cm
2
/g)
RequirementsItems
76
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
related to the packing density of powder. By using
spherical powder, the packing density of paste is
increased. The higher the packing density of paste, the
higher the fluidity of paste is. The packing density of
paste is related to the amount of retention water clusters
in suspension. The difference in amounts between the
total water and the retention water of paste (called free
water) affects the fluidity of paste. The smaller the
amount of retention water, the higher the fluidity of
paste. The amount of the retention water of paste with
PLS is smaller than that of the paste without PLS. By
the addition of water, the amount of the free water of
cement paste has the same values of the case as paste
with PLS. The fluidity of these pastes (AWP) is
increased but the fluidity of paste with PLS is larger
than that of AWP paste and the difference between the
fluidity of paste with PLS and AWP paste may be
contributed to a ball bearing effect. Therefore, the shape
or spherical effect of inorganic powders on the fluidity
of paste consists of the packing effect and the ball
bearing effect of powders.
Fig. 8 Relation between the spherical factor of
powders and the fluidity of cement pastes with
various types of powders (OPC: cement, PSS:
spherical fused silica, PCS: crushed fused silica, PBFS:
granulated blast furnce slag, PLS: limestone powder,
PFA: Fly ash, Dosage of SP: 1.6 mass%, W/P: 0.9 by
volume)
Different from granulated blast furnace slag, limestone
powder contains no intentionally added anhydrate or
gypsum. However, since there are cases where
limestone powder is used in large amounts, the quality
standard for limestone powder was made more rigorous
than for cement, based on the results of the chemical
analysis of the samples collected for the test at this time.
As for sulfur, it is important to confirm that the
presence of sulfur is not in the form of FeS. The
presence of FeS shows the possibility of developing
expansive cracking of the concrete.
Though limestone powder does not harden itself,
moisture contained in it exerts considerable influence
on the fluidity, so the standard is set for it.
Though in Japan there is little organic compound mixed
into limestone powder, in foreign countries it is
reported that in some cases a large amount of organic
compounds are contained. In this standard there is no
prescribed value for the organic compounds. However,
it is necessary to carry the total organic carbon analysis
in such cases where it is feared that a lot of organic
matter is mixed in and abnormality is observed in such
tests as compressive strength ratio tests. When a
material not conforming to this standard is to be used, it
is necessary to confirm that the material exerts no bad
influence on the properties of concrete.
(3) Granulated slowly cooled blast furnace slag
Granulated slowly cooled blast furnace slag has been
studied for the application of self compacting concrete.
The main component of granulated, slowly-cooled blast
furnace slag is the crystalline phase such as melilite (the
solid solution of gehlenite and akermanite) and
D-wallastinite and calcium thiosulfate is contained as
the minor component. Granulated slowly cooled blast
furnace slag is inert, but this reacts with CO2. Therefore,
the microstructure of concrete with granulated
slowly-cooled blast furnace slag becomes dense by
carbonation. The flow of mortar with granulated
slowly-cooled blast furnace slag and limestone powder
is shown (Fig. 9)[15]. The flow loss of mortar with
granulated slowly cooled blast furnace slag is smaller
than that of mortar with limestone powder. It is caused
by the fact that the hydration of C3A in cement is
retarded by leached thiosulfate ions from granulated
slowly cooled blast furnace slag.
Fig. 9 Influence of granulated slowly cooled blast
furnace slag on the fluidity of mortar
CFS: slowly cooled blast furnace slag, LSP: limestone
powder, number: fineness, SP/dosage
(4) Impurity from aggregates or mineral admixtures
Control of the addition of impurities from aggregates or
mineral admixtures is very important for the production
of high durable and self compacting concrete. The
fluidity of concrete containing superplasticizers is
remarkably decreased by clay minerals in aggregates.
The influence of montmorillonite on the fluidity of
paste for limestone powder. Limestone powder is used
as a model powder of inert cement is shown (Fig. 10).
When montmorillonite is added, the apparent viscosity
of paste with superplasticizers is drastically increased.
Superplasticizers are mainly adsorbed on
montmorillonite in the first stage. When the dosage of
77
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
polycarboxylate based superplasticizer is increased,
superplasticizers are adsorbed on limestone powder and
the fluidity of paste is improved. However, in the case
of naphthalene based superplasticizers, the fluidity of
paste is not improved by increasing the dosage. It is
thought that polycarboxylate based superplasticizer can
be dispersed by clay minerals, but naphthalene based
superplasticizers cannot be dispersed by clay minerlas
[16].
Fig. 10 Influence of clay mineral on the fluidity of
paste with superplaticizers
2.3 Superplasticizer/High Performance Concrete
Admixture
2.3.1 Introduction
Recently, the requirement for advanced concrete
performance is increasing according to the increase of
higher and larger concrete structures. SCC or Ultra
High Strength Concrete (UHSC) is an example of high
performance concrete and superplasticizer (SP) is one
of the most important materials for the development of
it. Superplasticizer is categorized into JIS A 6204 in
1995 and it is defined as “Chemical admixture which
has air entrainment and high water reduction and also
slump retaining performance”.
In this section, we discuss the history and recent status
of the improvements of superplasticizer developed by
major construction projects.
2.3.2 History of superplasticizer
Fluidizing agent became widely used in the 1970’s as a
counter measure on site for concrete pumping when the
unit water increased as a result of the depletion of good
quality aggregate. However, fluidization also had
several problems such as noise or complication of
quality control. As the solution for these problems,
superplasticizer, which has high water reducing effects
and slump retention, had been developed to avoid
fluidization on site. At first, E-naphthalene sulfonate
formalin condensate (BNS), which is one of main
dispersants for fluidizing agent based superplasticizer,
was developed in 1985. After that, polycarboxylate
(PC) based, melamine sulfonate formalin condensate
(MS), based and amino sulfonate based superplasticizer
were developed and commercialized one after the other
[17][18].
The history of superplasticizer product development is
distinguished by its main dispersant as shown in Fig. 11.
In the 1990’s when superplasticizer started to be uses,
more than 50% of products were BNS based. In 1995,
however, PC based products became more widely used
instead of BNS products and accounted for more than
85% of all products in 2006.
Fig. 11 History of product number of
superplasticizer
Furthermore, the total number of products peaked in
1998, and then began to decrease. From these facts, it
was considered that the main preferred component of
superplasticizer tends to be PC.
On the other hand, the requirement for increased
concrete strength in the architectural field supported the
development of superplasticizer. The first high strength
concrete (f’c = 30 N/mm2) was used to build the
Shiinamachi-apartment house in 1974.
Thereafter, since it became possible to produce high
strength concrete with enough flowability through the
improvement of superplasticizer, the maximum
compressive strength of concrete increased drastically.
Moreover, the result of a general technology
development project in the Ministry of Construction’s
“Development of Advanced Reinforced Concrete
Buildings Using High-Strength Concrete and
Reinforcement” also contributed to this drastic strength
increase. In particular, this project greatly contributed
to the progress of superplasticizer. Furthermore, in
order to produce lower W/C concrete, PC based
superplasticizer became the leading product instead of a
BNS based one and it became possible to produce f’c
of 60 to 100 N/mm2 of concrete.
Meanwhile in the field of civil engineering, improved
superplasticizer was also required for the progress of
SCC. SCC was developed by Okamura, et al. in 1988
and was used widely for large-scale structures in order
to secure the compactability for confined reinforcement
in national projects such as Akashi-Kaikyo Bridge or
Tokyo-bay Aqualine in around 1990.
Melamine
Amino sulfonate
E-Naphthalene sulfonate
Polycarboxylate
Number of product
Melamine
Amino sulfonate
E-Naphthalene sulfonate
Polycarboxylate
Number of product
78
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
In order to add an anti-segregation property for SCC,
the amount of fine particles was increased and W/C was
reduced. Superplasticizer, which has high dispersibility,
was required and the most useful superplasticizer was a
PC based one, having slower retardation and longer
slump flow retention than conventional one.
As described above, PC based superplasticizer became
a major product due to its higher dispersibility,
flowability retention, slower retardation and concrete
viscosity.
2.3.3 Role of polycarboxylate based
superplasticizer
The molecular structure of polycarboxylate is basically
characterized by the carboxyl group which adsorbs the
cement surface and polyethyleneoxide (PEO) chain
which exhibits a steric repulsive force as shown in Fig.
12 [19][20][21][22].
Additionally, PC can improve or add to the
performance of the admixture by controlling molecular
structure. This feature is also a major reason for the
wide use of PC. Co-polymer structures such as PC can
control the type and ratio of composed monomer.
Therefore, various types of PC polymers, which have
different effects on cement particles, can be produced
by polymer structure control. For example, by
increasing the ratio of the carboxylic group, high
dispersibility PC can be produced and by increasing
PEO chain density, long slump retention PC is able to
be synthesized. Furthermore, by co-polymerization
with 3rd or 4th functional group, new functions other
than dispersibility and dispersibility retention can be
attributed to PC based dispersant.
Fig. 12 Molecular structure and model of
polycarboxylate based polymer
2.3.4 Trends of recent PC based superplasticizer.
(1) A viscosity reducing type of superplasticizer
Recently, as described above, superplasticizer, which
has high water reduction properties, is widely used in
order to observe the upper limit of water amount unit
for concrete using low quality aggregate or for securing
durability. Even if superplasticizer can produce high
flowable concrete with a small water amount unit, the
concrete viscosity tends to increase. Therefore,
superplasticizer is not always good for workability
characteristics such as pumpability, compactability or
surface finishibility. As a result, improvements in
superplasticizer were required from ready mixed
concrete plants.
As a solution to this requirement, a viscosity-reducing
type of superplasticizer was launched from each
admixture supplier in around 2000. The main
component of this type of superplasticizer is also
categorized as a PC based dispersant, and this is a
typical example of new functions for further control of
PC structures. It is not possible to define the
relationship between structural features and functions
because the traits of molecular structure are not the
same in each supplier’s product. The introduction of
cationic parts or the optimization of monomer type and
ratio was applied as part of this improvement by each
manufacturer. The character of a viscosity-reducing
type of superplasticizer is summarized as follows:
1) Concrete viscosity can be reduced.
2) Workability characteristics such as pumpability,
compactability, finishibility is improved.
3) Changes in concrete performance by pumping are
small.
These performance characteristics were confirmed
according to the L-flow test (Tab l e 3 ) or pumping
pressure measurement by actual pumping examination
(Fig. 13).
Table 3 Comparison of L-flow (W/C = 45%)
Fig. 13 Pumping pressure
Acid Ester
Carboxylic
group
Main chain
Graft chain
Cement Surface
Acid Ester
Carboxylic
group
Main chain
Graft chain
Cement Surface
V1 V2
Viscocity Reducing 33.5 17.8 17.8 3.8 6.6
Conventional 33.0 13.1 14.0 5.0 4.5
Average
flow rate
(cm/sec.)
Slump: 20cm
Admixture
Slump
Flow
(cm)
Initial flow rate
(cm/sec.)
Flowing
time
(sec.)
V1 V2
Viscocity Reducing 33.5 17.8 17.8 3.8 6.6
Conventional 33.0 13.1 14.0 5.0 4.5
Average
flow rate
(cm/sec.)
Slump: 20cm
Admixture
Slump
Flow
(cm)
Initial flow rate
(cm/sec.)
Flowing
time
(sec.)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 20406080100
Holizontal convention length (m)
Pressure (N/mm2)
Conventional
Viscosity reducing
79
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
In addition, the viscosity of high strength concrete or
self compacting concrete became too high due to the
mix proportion of lower water to cement ratio, and their
workability performance also deteriorated. For this type
of concrete, it is possible to improve the workability by
using viscosity reduction of superplasticizer with no
segregation. The viscosity measurement result of
mortar in concrete is shown in Fig. 14. In this figure,
the Y axis indicates viscosity (P) relating to shear rate
and shear stress using B type viscometer. Usually, the
viscosity of concrete is increased by decreasing W/C.
When using a viscosity-reducing type of
superplasticizer, the viscosity of concrete is consistently
about 5% less than for conventional concrete which
uses conventional superplasticizer. Based on this effect,
the application of viscosity-reducing superplasticizer
for actual high strength/self compacting concrete is
increasing.
Fig. 14 Relation between W/C and viscosity
(2) Superplasticizer for ultra-high strength concrete
Recently, applications of ultra-high strength concrete
(UHC: f’c of more than 100 N/mm2) are increasing and
150 N/mm2 of concrete is starting to be used for actual
structures. For this type of concrete, it is necessary to
use not only improved cement or inorganic additives,
but also special superplasticizer, which has extremely
high dispersibility, in order to reduce viscosity and
retain slump-flow.
At present, superplasticizer for UHC with shrinkage
reducing effects is also being developed to reduce the
autogenous shrinkage, which is one of the major
problems of UHC.
2.3.5 Summary
The role of concrete admixture, including
superplasticizer, for the progress of high strength and
high performance concrete is important. The
worldwide progress within concrete and construction
technology development is extremely high and Japan,
in particular, has made many contributions in research.
In the future, it is necessary to consider how to
effectively contribute to saving natural resources and
energy in new technology developments.
2.4 Recent Technological Developments for
Promotion of SCC
2.4.1 Adjustment of mix-proportioning
Okamura and Ozawa have already proposed the simple
mix-proportioning system, assuming general supply
from ready-mixed concrete plants, in which the coarse
and fine aggregate contents were fixed so that
self-compactability can be achieved easily by adjusting
the water-powder ratio and superplasticizer dosage only
(Fig. 15).
Fig. 15 Rational mix-proportioning method for SCC
However, some mixing trials were necessary to fix the
appropriate water-powder ratio and superplasticizer
dosage because the relationship between these values
and the test results of the fresh concrete was rather
complicated. In 1997, Ouchi established the rational
adjusting method for the water to powder ratio and the
dosage of superplasticizer by analyzing the concrete’s
flow and funnel test results and by establishing the
simple relationship between the water-powder ratio and
the superplasticizer dosage and the flow and funnel test
results (Fig. 16) [2]. This method was described in
“Manual for Manufacturing of Self-Compacting
Concrete” by the National Ready-Mixed Concrete
Industry, Japan in 1998.
Fig. 16 Rational adjustment method for water to
powder ratio and dosage of superplasticizer
2.4.2 Automatic acceptance test on site
Since the degree of compaction in a structure mainly
depends on the self-compactability of concrete and poor
self-compactability cannot be compensated by the
construction work, self-compactability must be checked
for the whole amount of concrete just before casting on
1.0
1.5
2.0
2.5
3.0
28 30 32 34 36 38 40 42
W/C(%)
μ (PaS)
Conventional
Viscosity reducing
1.0
1.5
2.0
2.5
3.0
28 30 32 34 36 38 40 42
W/C(%)
μ (PaS)
Conventional
Viscosity reducing
G
GS
SP
P
S
S
P
P
50% of
50% of
solid volume
solid volume
40% of
40% of
mortar volume
mortar volume
can be fixed with material
can be fixed with material
parameters
parameters
W
W
to be fixed with trial
to be fixed with trial
mixing
mixing
Moderate deformability
Moderate deformability
& viscosity
& viscosity
G
GS
SP
P
S
S
P
P
50% of
50% of
solid volume
solid volume
40% of
40% of
mortar volume
mortar volume
can be fixed with material
can be fixed with material
parameters
parameters
W
W
to be fixed with trial
to be fixed with trial
mixing
mixing
Moderate deformability
Moderate deformability
& viscosity
& viscosity
Sp
Sp
P
P
*
*
c
c
R
Rc
c
V
Vw
w
V
Vp
pR
Rc
c
*
*
c
c
^0.5
^0.5
Water
Water-
-Powder Ratio
Powder Ratio (
(V
Vw
w
V
Vp
p)
)
Superplasticizer Dosage
Superplasticizer Dosage (
(Sp
Sp
P
P)
)
Deformability
Deformability
*
*
c
c
Viscosity
Viscosity R
Rc
c
V
Vw
w
V
Vp
pSp
Sp
P
P
Simple relationships
Simple relationships
R
R
c
c
*
*
c
c
^0.5
^0.5
*
*
c
c
R
R
c
c
Sp
Sp
P
P
*
*
c
c
R
Rc
c
V
Vw
w
V
Vp
pR
Rc
c
*
*
c
c
^0.5
^0.5
Water
Water-
-Powder Ratio
Powder Ratio (
(V
Vw
w
V
Vp
p)
)
Superplasticizer Dosage
Superplasticizer Dosage (
(Sp
Sp
P
P)
)
Deformability
Deformability
*
*
c
c
Viscosity
Viscosity R
Rc
c
V
Vw
w
V
Vp
pSp
Sp
P
P
Simple relationships
Simple relationships
R
R
c
c
*
*
c
c
^0.5
^0.5
*
*
c
c
R
R
c
c
80
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
site. However, the conventional testing methods for
self-compactability required sampling and this can be
extremely laborious if the self-compactability
acceptance test is to be carried out for the whole
amount of the concrete. A more suitable acceptance
test method for self-compactability was developed by
Ouchi (Fig. 17): Details are outlined below:
(1) The testing apparatus is installed between agitator
truck and pump on the job site. The whole amount
of the concrete is poured into the apparatus.
(2) If the concrete can flow through the apparatus, the
concrete can be considered as self-compactable in
the structure. If the concrete is stopped by the
apparatus, the concrete can be considered as having
insufficient self-compactability and the
mix-proportion has to be adjusted.
Fig. 17 Concept of automatic acceptance test on
site
This apparatus was successfully first used at the
construction site of the above-ground LNG tank of
Osaka Gas, and saved a considerable amount of
acceptance test work in 1997 to 1998 (Fig. 18) [23].
Fig. 18 Automatic acceptance testing apparatus of
SCC used for LNG tank of Osaka Gas
Also, the modified acceptance testing apparatus was
employed in the construction of the underground LNG
tank of Tokyo Gas to detect concrete with poor
deformability more accurately in 2000 to 2001 (Fig.
19) [24].
Fig. 19 Automatic Acceptance Testing Apparatus of
SCC used for LNG tank for Tokyo Gas
3. APPLICATIONS OF SCC
3.1 Immediate Cause for Employment of SCC
3.1.1 Introduction
It has been a long-cherished dream of engineers
involved in construction to be able to deposit and
consolidate concrete independent of the labors’ skill,
which is directly affected by the expertise knowledge
and experience in concreting. It was SCC that made this
dream come true, primarily from the aspects of
materials and proportioning. SCC is a representative
technology brought about by the development of new
materials, such as chemical admixtures for concrete and
new types of cement, and the technologies of concrete
proportioning and production methods.
The development of placing technologies in concert
with these has accelerated the practical application of
the SCC. SCC was first advocated by Okamura et al.
in 1986 and materialized as a prototype, referred to as
the “High Performance Concrete” in 1989 [25]. A
variety of self-compacting concrete has rapidly grown
on this starting point and have been put to practical use.
While it was initially used for limited applications, such
as members congested with steel sections and heavily
reinforcing areas and narrowed segments, its uses
subsequently expanded to applications intended for the
rapid and streamlined construction of long bridges
[26][27].
Currently, there is immediate cause for the employment
of SCC in practical structures. These needs can be
summarized as follows:
(1) To shorten the construction period for large scale
construction
(2) To assure compaction in the confined zones of
reinforcing bars where vibrating compaction is
difficult or impossible
(3) To eliminate noise or vibration due to compaction in
concrete products
(4) To assure durability with no initial defect of
81
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
concrete or sure compaction
The examples of applications of SCC are described as
follows.
3.1.2 Large scale construction
(1) Automation of concrete casting
The anchorages of Akashi-Kaikyo Bridge, a suspension
bridge with the longest span in the world (1,991 meters),
which was opened in April 1998, is a typical example
(Fig. 20). Self-compacting concrete was used in the
construction of the two anchorages of the bridge. A
new construction system, which makes full use of the
performance of self-compacting concrete, was
introduced for this. The concrete was mixed at the
batcher plant beside the site, and was then pumped out
of the plant. It was transported 200 meters through
pipes to the casting site, where the pipes were arranged
in rows 3 to 5 meters apart. In the final analysis, the
use of self-compacting concrete shortened the
anchorage construction period by 20%, from 2.5 to 2
years [28].
Fig. 20 Anchorage of Akashi-Kaikyo Bridge
(2) Less restriction of concrete works
Self-compacting concrete was used in the PC dyke for
preventing the leakage of the large LNG tank of the
Osaka Gas Company (Fig. 21) [29].
Fig. 21 LNG tank of Osaka Gas using SCC
The adoption of self-compacting concrete means that:
- The number of castings of concrete was reduced from
14 to 10, as the height of one cast of concrete was
increased.
- The number of concrete workers was reduced from
150 to 50.
- The construction period of the structure decreased
from 22 to18 months.
3.1.3 Structure where vibrating compaction is
difficult or impossible
(1) An underground LNG tank with rigid connection
between bottom slab and side wall
There have been many underground LNG tanks
constructed by Tokyo Gas Company for more effective
use of the land in the Tokyo area. In the latest
underground LNG tank, the connection between the
bottom slab and the side wall was changed from a pin
connection to a rigid one for more load carrying
capacity and water tightness (Fig. 22). The amount of
steel was increased to as much as 400 kg/m3 of concrete
and then SCC was employed to assure the compaction
of the structure from 2000 to 2001 [24][30]. SCC was
successfully compacted in the structure (Fig. 23).
Fig. 22 Underground LNG tank of Tokyo Gas with
rigid connection between bottom slab and side wall
Fig. 23 Increased amount of steel by rigid
connection between bottom slab and side wall
(2) High piers of bridges
SCC was employed in the high piers of Omi Oodori
Ohashi Bridge, New Meishin Expressway (Fig. 24).
The piers are 65 meters in height, and 58 meters from
the bottom of this pier to the top and rigid foundations
were the focus of the work for this substructure project.
Since the span of this bridge is long, high strength
concrete (design strength = 50 MPa) and also high
Conventional Pin
Connection
Conventional Pin
Conventional Pin
Connection
Connection
Bottom SlabBottom Slab
Bottom Slab
Side Wall
Side Wall
Side Wall
9.8m
9.8m
2.2m
2.2m
Rigid Connection
Rigid Connection
Rigid Connection
2.8m
2.8m
8.0m
8.0m
Rigid CornerRigid Corner
Rigid Corner
Bottom Slab
Bottom Slab
Bottom Slab
Side WallSide Wall
Side Wall
Conventional Pin
Connection
Conventional Pin
Conventional Pin
Connection
Connection
Bottom SlabBottom Slab
Bottom Slab
Side Wall
Side Wall
Side Wall
9.8m
9.8m
2.2m
2.2m
Rigid Connection
Rigid Connection
Rigid Connection
2.8m
2.8m
8.0m
8.0m
Rigid CornerRigid Corner
Rigid Corner
Bottom Slab
Bottom Slab
Bottom Slab
Side WallSide Wall
Side Wall
82
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
strength reinforcing bars (yield strength = 685 MPa)
were necessary to ensure earthquake resistance so
high-strength SCC was employed in these piers [31].
Fig. 24 Omi Oodori Ohashi Bridge and its
arrangement of re-bars of pier
(3) Superstructures of large bridges
In recent years, applications of SCC to the
superstructures of bridges have been increasing. These
include prestressed-concrete girders congested with
steel reinforcing bars and sections [32] and the upper
floor beams of a reinforced concrete rigid-frame bridge
for which shear reinforcement has been substantially
increased to conform to the reviewed seismic codes.
More recently, SCC has been used as filling concrete
for the floor slabs and steel box girders of
steel-concrete composite structures.
Active application of SCC is anticipated for bridge
superstructures, to meet the needs for reliable filling of
members confined with reinforcement, such as the
superstructures of prestressed-concrete bridges, and
increasing uses of steel-concrete composite bridges.
(4) Full sandwich structure for immersed tunnel
Self-compacting concrete can greatly improve
construction systems previously based on conventional
concrete requiring vibrating compaction. This sort of
compaction, which can cause segregation easily, has
been an obstacle to the rationalization of construction
work. Once this obstacle has been eliminated, concrete
construction can be rationalized and a new construction
system, including formwork, reinforcement, support
and structural design, can be developed (Fig. 25).
Fig. 25 Rational combination of steel and SCC
One example of this is steel-concrete composite
structure and it is the so-called sandwich structure
where concrete is filled into a steel shell. This sort of
structure has already been completed in Kobe, and
could not have been achieved without the development
of self-compacting concrete because there is no room
for vibrating compaction in the structure (Fig. 26)
[33][34][35].
Fig. 26 Full sandwich structure that cannot
achieved without SCC
(5) MMST method
Another example of steel-concrete composite is
particularly an innovative method characteristic of SCC,
combining it with a new construction method referred
to as the Multi-Micro Shield Tunneling method (MMST
method), whereby a large section tunnel is constructed
by connecting multiple layers of rectangular shield
tunnels in urban area (Fig. 27) [36].
Fig. 27 Large-section tunnel of steel-concrete
composite construction by MMST method
(6) CFT structures
In addition to the two examples described above,
concrete filled steel tube (CFT) columns is also one of
the examples of the rational combination of concrete
and steel that cannot be achieved without SCC. CFT
is the most frequent application of SCC for buildings.
Self-Compacting Concrete
No Vibration Resistance to Segregation
Less Restriction
to Design
Less Restriction
to Practice
New Type of Structure Rational Construction
System
Rational Combination of
Concrete & Steel
DURABLE & CHEAP concrete structures
Self-Compacting Concrete
No Vibration Resistance to Segregation
Less Restriction
to Design
Less Restriction
to Practice
New Type of Structure Rational Construction
System
Rational Combination of
Concrete & Steel
DURABLE & CHEAP concrete structures
83
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
When placed in CFT structures, concrete is required to
be sufficiently pumpable to a high level and have
self-compacting properties so as to be filled in steel
tubes without compaction during bottom-up pumping.
The number of high-rise buildings of more than 60
meters using SCC in Japan are shown in Fig. 28 [37].
Other applications of SCC for building structures are;
reinforced concrete buildings with dense reinforcement
or complicated shape to secure the filling of concrete,
and the construction of strengthening members for
earthquake resistance where internal vibration is unable
to be applied.
Fig. 28 The numbers of high-rise CFT buildings
The structure of CFT is confined to concrete column
structures made by filling concrete into the steel pipe
columns and are mainly used for high-rise buildings.
CFT structures have joints with concrete filled steel
tube columns and steel beams, and diaphragms to
transmit the load from beam to column in the joint as
shown in Fig. 29 [38].
Fig. 29 Column and beam joint of CFT
For the construction of CFT with bottom-up concreting,
pumping concrete from the bottom of a column from a
low story level to high story levels, as shown in Fig. 30
[39] and Fig. 46, is often adopted because filling
concrete into joints with diaphragms prevents voids.
The height of the bottom-up concreting in a column is
generally about 15 meters to 60 meters, and there are
even cases of 80 meters or more.
)LJ%RWWRPXSFRQFUHWLQJRI&)7
For bottom-up concreting, SCC is required to have such
properties as; sufficient pumpability to pump-up to a
high level, less viscosity and sufficient resistance to
segregation to prevent plugging or a sudden increase of
pumping pressure when passing through diaphragms. A
powder type of SCC with a high amount of
cementicious materials, such as low heat cement or
mineral admixtures as silica fume or fly ash, is often
used.
The relationship between the pumping height and the
pressure at the bottom of a column is shown in Fig. 31
[40]. The pumping pressure at the bottom of the column
becomes about 1.1 to 1.3 times larger than the liquid
pressure equivalent to the unit weight of fresh concrete.
SCC is required to retain workability while pumping,
and after the concrete is filled, SCC also requires less
bleeding and settlement. If bleeding and settlement of
the concrete occurs, the filling and strength of the
concrete at joints with diaphragms becomes
insufficient.
)LJ5HODWLRQVKLSEHWZHHQSXPSLQJKHLJKWDQG
SUHVVXUH
The application of SCC in the highest building in Japan
with 70 stories is shown (Fig. 32) [41]. The specified
design strength of the concrete was 35 N/mm2 and SCC
with a slump-flow value of 600 mm using three
㪈㪇
㪉㪇
㪊㪇
㪋㪇
㪈㪐㪏㪏
㪈㪐㪏㪐
㪈㪐㪐㪇
㪈㪐㪐㪈
㪈㪐㪐㪉
㪈㪐㪐㪊
㪈㪐㪐㪋
㪈㪐㪐㪌
㪈㪐㪐㪍
㪈㪐㪐㪎
㪈㪐㪐㪏
㪈㪐㪐㪐
㪉㪇㪇㪇
㪉㪇㪇㪈
㪉㪇㪇㪉
㫐㪼㪸㫉
㪥㫌㫄㪹㪼㫉㫊㩷㫆 㪽㩷㪙㫌㫀㫃㪻㫀 㫅㪾㫊
$JLWDWLQJ7UXFN
&RQFUHWH3XPS
9DOYH
3XPSLQJ
$JLWDWLQJ7UXFN
&RQFUHWH3XPS
9DOYH
3XPSLQJ
/LTXLG3UHVVXUH
+HLJKWRI&RQFUHWHP
3UHVVXUHNJIFP
/LTXLG3UHVVXUH
+HLJKWRI&RQFUHWHP
3UHVVXUHNJIFP
84
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
component cements containing fly ash and blast furnace
slag, and a viscosity-modifying admixture made of
polymer was used. The pumping height was 40 meters,
and approximately 900 m3 of SCC was used for 66
columns. During construction, the filling of fresh
concrete was monitored by video cameras from the top
of each column, and the quality of the concrete was
tested using subsidiary columns at the top of the
columns.
Fig. 32 Application of bottom-up concreting of CFT
to 70-story building
High strength SCC of 100 N/mm2 was applied to a
high-rise building of 248 meters [42]. SCC was used in
bottom-up concreting from the basement to the 43rd
story. Silica fume premixed cement and special
polycarboxylate-based high range water reducer with
excellent cement dispersibility was used to improve the
fluidity of SCC with a very low water-cement ratio of
0.18.
(7) Structures with complicated shape
The application of SCC for the traveling girder of a
movable roof for a dome stadium is shown (Fig. 33).
Because the girder was inclined and had a complicated
shape with dense reinforcement, 10,000 m3 of the
powder type of SCC was used to secure filling [43].
)LJ$SSOLFDWLRQRI6&&WRWUDYHOLQJJLUGHU
As shown in Fig. 34, reinforced concrete columns and
beams were designed as tree-like shape, SCC was
placed from the bottom of the columns and pumping
pressure was applied to secure the filling in
complicated forms and reinforcement [44].
)LJ$SSOLFDWLRQRI6&&WRWUHHVKDSHGVWUXFWXUH
(8) Seismic retrofitting & repairing
During the construction of strengthening members in
existing structures for earthquake resistance, the shear
wall or column is installed between existing frames. In
this case, because internal vibration tends to be difficult,
but nevertheless is necessary to fill concrete properly
between existing members, SCC is effective in filling in
narrow members and improving bond strength. The
construction of SCC by pressured pumping for
post-installed columns is shown (Fig. 35)[45].
)LJ$SSOLFDWLRQRI6&&WRVWUHQJWKHQLQJ
FROXPQ
Also, in addition to the application of repairing
patching for damaged segments [46], the number of
applications of jacketing reinforced concrete members,
for the purpose of seismic retrofitting, has been
increasing in recent years [47][48]. Retrofitting of
existing structures has been a pressing issue since the
Great Hanshin Earthquake in 1995. This kind of repair
and strengthening work is therefore expected to
increase.
3.1.5 Concrete Products
Self-compacting concrete is often employed in concrete
products to eliminate the noise of vibration (Fig. 36).
This improves the working environment at plants and
makes it possible for concrete product plants to be
located in the urban area (Fig. 37)[49].
5HFWDQJXODU6WHHO3LSH
[PP
5HFWDQJXODU6WHHO3LSH
[PP
&LUFXODU6WHHO3LSHPP
5HFWDQJXODU6WHHO3LSH
[PP
5HFWDQJXODU6WHHO3LSH
[PP
&LUFXODU6WHHO3LSHPP
85
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
Fig. 36 Application of SCC to segment for shieled
tunnel
Fig. 37 Improved environment in and around
concrete products plant by SCC
3.1.6 To ensure durability by no initial defects of
concrete or sure compaction
In addition to effective compaction in the structure,
SCC has high durability due to the fact that there are no
initial defects. The water to cement (or powder) ratio
of SCC is less than 30% by weight so the amount of
bleeding and laitance is almost zero. That means the
possibility of cold joints is very low. By using this
advantage, there have been some examples of the
application of SCC of achieving durability.
For example, SCC was applied to the lining of some
tunnels to prevent concrete blocks falling due to cold
joints. Also, SCC can be completely compacted into
the arch crown of the lining of a tunnel (Fig. 38).
Fig. 38 Application of SCC to tunnel lining: free
from initial defects and sure compaction
SCC was also employed in the cylindrical diaphragm
walls surrounding underground storage tanks, in which
the adoption of SCC with high strength (specified
strength of 60 N/mm2) permitted the reductions in the
thickness of diaphragm walls to nearly half the
conventional thickness [50]. The water-tightness was
also dramatically improved by the reliable filling of
concrete. Though diaphragm walls have conventionally
been regarded as temporary structures, their high
rigidity and water-tightness means they are now often
regarded as permanent walls, for which the bottom slab
thickness of the storage tanks could be reduced to
nearly one third of conventional values. SCC has been
applied to a relatively large number of diaphragm walls
[51] and is expected to be used more to improve the
quality of diaphragm walls, for which consolidation has
conventionally been difficult due to the slurry water.
Positive mass concrete measures have been taken for
the application to large watertight structures [52][53]
and the mass concrete bottom slab of vertical shafts for
storm water storage tunnels [54] in the use of SCC
made using a low-heat type Portland cement, limestone
powder, and an expansive additive. Also, a large area is
cast simultaneously in these cases by such pumping
methods as the branch pipe method (Fig. 39) [52] so as
to reduce the number of construction joints.
Fig. 39 Simultaneous placing of SCC to a large
area by branch pipe pumping
3.2 Reduction in Cost by SCC
3.2.1 Introduction
There are three reasons for the use of SCC in terms of
the reduction in cost.
(1) Reduction in the initial cost by replacement of
conventional concrete with SCC only
(2) Reduction in the initial cost by adopting new
designs or construction systems making use of the
performance of SCC
(3) Reduction in the repair and maintenance costs
compensating for the increase in the initial cost
The examples of reductions in cost with SCC that have
Conventional concrete
Conventional concrete
SCC
SCC
Conventional concrete
Conventional concrete
SCC
SCC
86
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
been achieved in practice are described below.
3.2.2 Reduction in initial cost by replacement with
SCC only
There are not so many examples, except for the
manufacturing of concrete products, where the
immediate cause for the employment of SCC is the
elimination of noise and vibration due to the
compaction of concrete.
Another of the examples is the application of SCC into
segments of shield tunnels. The cost of the
manufacturing items were reduced, except for the
material itself. However, the total manufacturing
costs can be reduced by 14% (Fig. 40).
Fig. 40 Reduction in manufacturing cost of tunnel
segment by SCC
Both SCC’s quantity (in volume) used in concrete
products (Fig. 41) and share of SCC the market in
concrete products (Fig. 42) have already exceeded
those of ready-mixed concrete in Japan. That is
because the reduction in cost for concrete products
using SCC and the merit of eliminating noise and
vibration due to compaction are very clear [49].
Fig. 41 Volume of SCC cast in Japan excluding for
CFT
Fig. 42 Share of SCC in the market of RMC and
concrete products
3.2.3 Reduction in initial cost by adopting new
designs or construction systems by making use of
performance of SCC
The performance of SCC is not only judged on
self-compactability but also high-strength and high
resistance against the penetration of harmful substances.
The design and construction system of concrete
structures can be rationalized or improved so that the
total construction cost can be reduced.
(1) Above-ground LNG tank
The employment of SCC with the compressive strength
of 60 N/mm2 made the cross section of the PC dyke of
an LNG tank smaller. SCC was developed from
high-strength concrete due to its very low water to
cement ratio and no special requirements of material,
admixture or curing is required for achieving the
compressive strength of 60 N/mm2. The smaller cross
section lead to a smaller dead load, which resulted in a
smaller number of piles for the foundation (Fig. 43).
In the final analysis, the initial cost was reduced by
12% by the employment of SCC (Fig. 44) [23].
Fig. 43 Smaller cross section of LNG tank by
high-strength SCC
Also, the quality assurance for concrete was
rationalized in the construction site of the LNG tank of
Osaka Gas by the combination of the automatic
Re
Re-
-
bar
bar
Form
Form
work
work Process
Process
ing
ing
Metal joint
Metal joint Facility
Facility Trans
Trans
port
port
Conventional Concrete Segment
Conventional Concrete Segment
SCC Segment
SCC Segment
Concrete
Concrete
+Environmental improvement
+Environmental improvement
-
-14%
14%
Re
Re-
-
bar
bar
Form
Form
work
work Process
Process
ing
ing
Metal joint
Metal joint Facility
Facility Trans
Trans
port
port
Conventional Concrete Segment
Conventional Concrete Segment
SCC Segment
SCC Segment
Concrete
Concrete
+Environmental improvement
+Environmental improvement
-
-14%
14%
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Year
0
100
200
300
400
500
Volume of SCC (*1,000 m^3)
RMC Concrete products
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Year
0
0.5
1
1.5
2
Share of SCC (%)
RMC Concrete products
87
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
acceptance test and information technology systems.
All the information on the manufacturing and quality of
SCC was collected in the central operation center
through an information network and could be
controlled remotely by testing software (expert) and
could be carried out as needed (Fig. 45) [29]. Of
course, concrete with insufficient self-compactability
can be stopped automatically by the apparatus. The
reduction in cost for the quality control assurance by
SCC is large.
Fig. 44 Reduction in cost for above-ground LNG
tank by high-strength SCC
Fig. 45 Remote and centralized control and
assurance system for quality of SCC by IT
(information technology) and automatic
acceptance test
(2) Full sandwich structure for immersed tunnel
The so-called full sandwich structure also achieved a
reduction in initial costs by 6.5% compared with the
conventional open sandwich structure despite having
more steel (Fig. 46) [55]. That is because the
reduction in cost was mainly for reinforcing bars (the
material itself, assembling and arrangement), formwork
and temporary work that is indispensable for the
construction of conventional concrete (Fig. 47). Also,
the cost for the dock was reduced due to the shorter
period for the concrete work.
Fig. 46 Reduction in initial cost for full sandwich
structure by SCC
Fig. 47 Rational full sandwich structure compared
with conventional sandwich structure
3.2.4 Reduction in repair and maintenance costs
compensating for an increase in initial costs
In recent years, its applications in the secondary lining
of tunnels have been increasing. In regard to the NATM
tunneling, steel, fiber-reinforced, self-compacting
concrete has been applied to the reinforced concrete
lining section of a tunnel portal constructed in weak
ground. It has also been applied to the reinforced
concrete lining section of a tunnel designed to be
earthquake-resistant to achieve reliable placement into
densely reinforced members while ensuring the quality.
Also, in an application making the most of its high
strength compared with conventional lining concrete,
reductions in the tunnel wall thickness were achieved
[56] by using an expansive additive to inhibit shrinkage
cracking resulting from a decrease in wall thickness.
For the secondary lining of small-diameter shield
tunnels, SCC was used to improve the cohesion at
construction joints and the placeability in narrow
spaces [57]. The uses for SCC are expected to increase
in the future amid the strong demand for measures to
prevent spalling of lining concrete.
However, the formwork has to be strengthened because
SCC’s lateral pressure on the formwork has to be
designed as liquid due to its self-compactability (Fig.
48) in addition to the increase in the material cost.
Reduction in Cost for Concrete Works in total
Reduction in Cost for Concrete Works in total:
:
-
-12%
12%
40 N/mm
2
60 N/mm
2
1,100 mm 800 mm
Concrete strength
Concrete strength
Thickness
Thickness of
of
PC
PC D
Dyke
yke
Amount of
Amount of
concrete
concrete 13,000 m
3
9,500 m
3
-8,000 tons
Dead load
Dead load
Number of piles
Number of piles 1,353 1,293
Reduction in Cost for Concrete Works in total
Reduction in Cost for Concrete Works in total:
:
-
-12%
12%
40 N/mm
2
60 N/mm
2
1,100 mm 800 mm
Concrete strength
Concrete strength
Thickness
Thickness of
of
PC
PC D
Dyke
yke
Amount of
Amount of
concrete
concrete 13,000 m
3
9,500 m
3
-8,000 tons
Dead load
Dead load
Number of piles
Number of piles 1,353 1,293
Automatic record of
measurement of material
weight & adjustment of
mix-proportioning
Quality control &
assurance of
concrete
Internet
Internet
Construction
Construction
site
site
RMC plants
RMC plants
Expert
Expert
History of index for
quality of SCC
䊚䉨䉰⽶⩄୯䋨䌁䋩
⚦㛽᧚䈱⴫㕙᳓₸䋨䋦䋩
Indicator of power for mixing
Technical support
Technical support
& advice
& advice
Automatic record of
measurement of material
weight & adjustment of
mix-proportioning
Quality control &
assurance of
concrete
Internet
Internet
Construction
Construction
site
site
Construction
Construction
site
site
RMC plants
RMC plants
RMC plants
RMC plants
Expert
Expert
Expert
Expert
History of index for
quality of SCC
䊚䉨䉰⽶⩄୯䋨䌁䋩
⚦㛽᧚䈱⴫㕙᳓₸䋨䋦䋩
䊚䉨䉰⽶⩄୯䋨䌁䋩
⚦㛽᧚䈱⴫㕙᳓₸䋨䋦䋩
Indicator of power for mixing
Technical support
Technical support
& advice
& advice
Open
Open
sandwich
sandwich
structure
structure
Full
Full
sandwich
sandwich
structure
structure
using
using
SCC
SCC
Steel
Steel
Re
Re-
-bar
bar
Shear
Shear
connector
connector
Formwork
Formwork
Concrete
Concrete
Dock
Dock
Anti
Anti-
-corrosive
corrosive coating
coating
Temporary work
Temporary works
s
-
-6.5%
6.5%
Ancially
Ancially
works
works
Open
Open
sandwich
sandwich
structure
structure
Full
Full
sandwich
sandwich
structure
structure
using
using
SCC
SCC
Steel
Steel
Re
Re-
-bar
bar
Shear
Shear
connector
connector
Formwork
Formwork
Concrete
Concrete
Dock
Dock
Anti
Anti-
-corrosive
corrosive coating
coating
Temporary work
Temporary works
s
-
-6.5%
6.5%
Ancially
Ancially
works
works
Open Sandwich
Open Sandwich
Structure
Structure
Full Sandwich
Full Sandwich
Structure
Structure
Open Sandwich
Open Sandwich
Structure
Structure
Full Sandwich
Full Sandwich
Structure
Structure
88
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
These types of applications have been limited at this
moment.
Fig. 48 Application of SCC into tunnel lining: higher
cost for material and formwork despite of its high
durability
4. PROSPECTS OF SCC IN FUTURE
In most applications, the employment of SCC without
any change of design or construction system cannot
reduce the initial costs. The cost of labor for vibrating
compaction is less than the increase in the material
costs of SCC because the price of SCC from the
ready-mixed concrete industry in Japan is at least as
much as 1.5 times as expensive as that of conventional
concrete.
Due to no initial defects or high penetration resistance
against harmful substances like chloride ion, the repair
and maintenance costs for SCC structures should be
lower than that of conventional concrete (Fig. 49). In
addition, predictions for the life time costs of SCC
structures in simulations should be more accurate than
that of conventional concrete structures because there is
less influence of construction work on the performance
of SCC structures since there is no vibrating
compaction required (Fig. 50).
Fig. 49 Merit of SCC in terms of lifecycle cost
Following the financial crisis of the Japanese
Government, the necessity for the reduction in
construction costs has been advocated since 2000 and
the market share of SCC has not increased as expected.
Recently, so-called Semi-Self-Compacting Concrete,
cheaper than SCC, was developed requiring slight
vibrating compaction and has been applied into many
practical structures following the high price of SCC.
The evaluation system for the lifetime costs for
concrete structures is indispensable so that we may
ascertain what the influence is of the selection of the
type of concrete material in use on the long term
durability, resulting in the lifecycle cost.
Fig. 50 Merit of SCC in terms of estimation of
lifecycle cost of concrete structures
REFERENCES
1. Japan Society of Civil Engineers “Recommendation
for Mix Design of Fresh Concrete and Construction
Placement related Performance of Evaluation” 2007.
2. Okamura, H. and Ouchi, M. “Self-compacting high
performance concrete” Journal of Advanced
Concrete Technology of Japan Concrete Institute, Vol.
1, No. 1, Apr., 2003, pp.5-15.
3. Japan Cement Association “Report of the Fluidity
Research Committee (in Japanese)” 2003.
4. Japan Concrete Institute “Report of the Cementitious
Materials and Aggregates Research Committee (in
Japanese)” 2005
5. Sakai, E., Yamada, K., and Ohta, A. “Molecular
structure and dispersion-adsorption mechanisms of
comb-type superplasticizers used in Japan” Journal
of Advanced Concrete Technology, Vol.1, 2003,
pp.16-25.
6. Yamada, K., et al. “Combined effect of cement
characteristics on the performance of
superplasticizers -an investigation in real cement
plants” Proc. 8th CANMET/ACI International
Conference on Superplasticizers and Other Chemical
Admixtures in Concrete, Supplementary Papers,
2006, pp.159-174.
7. Sakai, E., et al. “Influence of superplasticizers on the
fluidity of cements with different amount of
aluminate phase” Proceedings of the 2nd
International Symposium on Ultra High Performance
Concrete, 2008, pp.85-92.
8. Ministry of Economy,Trade and Industry “Report
for Cement Industry in Recycling Society” 2003.
9. Oosaki, M. “Material design of cement for the
utilization of waste in cement plant” Doctoral
Dissertation from Tokyo Institute of Technology,
2003.
10. Sakai, E., et al. “Interaction between
superplasticizers and eco-cement” Proceedings of
8th CANMET/ACI International Conference on
Superplasticizers and other chemical admixtures in
Possibility
Possibility
Lifecycle cost
Lifecycle cost
SCC
SCC
structure
structure
Conventional concrete
Conventional concrete
structure
structure
Accurate
Accurate
estimation
estimation
Possibility
Possibility
Lifecycle cost
Lifecycle cost
SCC
SCC
structure
structure
Conventional concrete
Conventional concrete
structure
structure
Accurate
Accurate
estimation
estimation
INITIAL COST
INITIAL COST REPAIR & MAINTENANCE
REPAIR & MAINTENANCE
Conventional
Conventional
concrete
concrete
structure
structure
SCC
SCC
structure
structure
REPAIR &
REPAIR &
MAINTENANCE
MAINTENANCE
INITIAL COST
INITIAL COST
INITIAL COST
INITIAL COST REPAIR & MAINTENANCE
REPAIR & MAINTENANCE
Conventional
Conventional
concrete
concrete
structure
structure
SCC
SCC
structure
structure
REPAIR &
REPAIR &
MAINTENANCE
MAINTENANCE
INITIAL COST
INITIAL COST
89
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
concrete, Supplementary Paper, 2006, pp.227-237.
11. Sakai, E., et al. “Influence of granulated
blast-furnace slag on the fluidity of cement having
different aluminate phase contents (in Japanese)”
Cement Science and Concrete Technology., No.61,
2007, pp.8-13.
12. Ichinose, R., et al. “Influence of limestone powder
on the fluidity of cement having different aluminate
phase contents” to be presented.
13. Japan Concrete Institute “Report of the Limestone
Powder Research Committee (in Japanese)” 1998.
14. Sakai, E., et al. “Limestone powder concerning
reaction and Rheology” Proc. Shigeyoshi Nagataki
Symposium, The Fourth CANMET/ACI/JCI
International Conference on Recent Advanced in
Concrete Technology, 1998, pp.41-54.
15. Morioka, M., et al. “Mechanisms for the
improvement of fluidity by granulated slowly cooled
granulated slag (in Japanese)” Concrete Technology,
Vol.14, 2003, pp.67-74.
16. Atarashi, D. “Fluidity of inorganic powder –water
suspension with polymer dispersant” Doctoral
Dissertation from Tokyo Institute of Technology,
2003.
17. Material Society of Japan “Handbook of Concrete
Admixtures (in Japanese)” NTS Co. Ltd., 2004.
18. Hattori, K. “Physical property and high strength
development mechanism of special water reducing
agent (in Japanese)” Concrete Journal, Vol.14, No.3,
1976, pp.12-19.
19. Furusawa, K. “Adsorption and dispersion stability
effect of polymer (in Japanese)” Polymer Journal,
Vol.40, Dec., 1991, pp.786-789.
20. Mackor, E. L., Journal of Colloid Interface Science,
Vol.6, 1951, p.492.
21. Fischer, E. W. “Kolloid-Z” 160, 1958, p.120.
22. Yoshioka, K., et al. “Role of steric repulsive effect
of superplasticizer on cement particle dispersion (in
Japanese)” Concrete Research and Technology,
Vol.16. No.1, 1994, pp.335-340.
23. Kitamura, H., Nishizaki, T., Ito, H., Chikamatsu, R.,
Kamada, F. and Okudate, M., “Construction of
pre-stressed concrete outer tank for LNG storage
using high-strength self-compacting concrete” Proc.
of the International Workshop on Self-Compacting
Concrete, Aug., 1999, pp.262-291.
24. Nakano, M. “Technological trend and latest
technological development of LNG in-ground
storage tanks” Journal of JSCE, No. 679, VI-51, Jun,
2001, pp. 1-20.
25. Ozawa, K., Maekawa, K. and Okamura, H. “High
performance concrete based on durability of
concrete” Proceedings of the 2nd East Asia-Pacific
conference on Structural Engineering and
Construction, Vol. 1, Jan., 1989, pp.445-456.
26. Kogo, M., Shimada, M., Suzuki, K., Nakagawa, O.
and Yokozeki, K. “Rapid construction of mass
concrete for the inside structures at Kawasaki
Man-Made Island on Trans-Tokyo Bay Highway (in
Japanese)” Concrete Journal, Vol. 33, No. 12, Dec.,
1995.
27. “Mix-proportion test, field experimental work and
actual work of highly-flowable concrete for
Kurusima Bridge 10A Tunnel Anchorage (in
Japanese)” Honshi Technical Report, Vol. 20, No.80,
1996, 1996, pp.40-49.
28. Kashima, S., Kanazawa, K., Okada, R. and
Yoshikawa, S. “Application of self-compacting
concrete made with low-heat cement for bridge
substructures of Honshu-Shikoku Bridge Authority”
Proceedings of the International Workshop on
Self-Compacting Concrete, Mar. 1999, pp.255-261.
29. Nishizaki, T. “Rationalization of concrete works by
self-compacting concrete (in Japanese)” Doctoral
Dissertation to Kyoto University, Jan., 2002.
30. Kawamura, Y. “The application of self-compacting
concrete to LNG underground storage tank (in
Japanese)” Journal of Pre-stressed Concrete, Vol. 45,
No.2, 2003, pp.49-55.
31. Nakajima, Y. “High strength self-compacting
colored concrete for Ritto Bridge substructure (New
Meishin Expressway)” Proceedings of the 1st fib
Congress, Osaka, Oct., 2002, pp.137-146.
32. Hosono, H., Miyazaki, M. and Uchimura, T.
“Construction of pre-stressed concrete bridge of
suspended from below by cables and deviation struts
(in Japanese),” Proceedings of Annual Conference of
the Japan Society of Civil Engineers, Vol. 54, 1999,
pp. 398-399.
33. Shishido, T., Shiraiwa, S, Ishii, J, Yamamoto, S &
Kume, H. “Pouring works of high fluidity concrete
for immersed tunnel by steel-concrete composite
structure” Proceedings of the International Workshop
on Self-Compacting Concrete, pp.328-346, Kochi,
Japan, 1999.
34. Ojima, R., Jodai, T., Nakashima, Y. and Kozawa, K.
“Pouring works of high fluidity concrete for Kobe
Port Minatojima Tunnel (in Japanese)” Concrete
Journal, Vol. 34, No. 8, 1996, pp.21-28.
35. Shindoh, T., Kawamura, R., Yamamoto, Y. and
Fujimura, M. “Application of super-workable
concrete with viscosity agent and powder to
immersed tunnel with full sandwich structure (in
Japanese)” Proceedings of the Japan Concrete
Institute, No. 20, Vol. 2, 1998, pp.511-516.
36. Tanaka, M., Mori, K. and Shindoh, T. “Application
of self-compacting concrete to steel segments of
multi-micro shield tunneling method” Proceedings of
the Second International Symposium on
Self-Compacting Concrete, 2001, pp.651-660.
37. The data on Japan Building Center, Building Letter,
1988-2003.
38. Association of New Housing Technology “Standard
for Design and Construction of Concrete Filled Tube
Structure in Japanese” 2002.
39. Oike, T., Kawaguchi, T. and Koshiro, Y.
“Pumping-up concrete for concrete filled steel tube
structures (in Japanese)” Cement and Concrete, No.
680, 2003.
40. Yonezawa, T., Okuno, T., Mitsui, K., Numakura, K.,
Oura, T. and Sato, M. “Bottom-up concreting into
steel tube column filled with ultra high strength
90
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
concrete using silica fume (in Japanese)” Concrete
Journal, Vol. 31, No. 12, 1993.
41. Mabuchi,Y. “Application of super fluidity concrete
(in Japanese)” Construction, No. 330,1993.
42. Tsuji, D., Kojima, M., Mitsui, K., Mori, K. and
Kono, T. “Bottom-up concreting of 100 MPa
high-strength concrete into concrete filled steel tube
columns” 2008.
43. Izumi, I. “Concreting of super workable concrete
(in Japanese)” Concrete Journal, Vol. 32, No. 7,
1994.
44. Araya, M., Sato, T., Shinohara, M. and Inoue, K.
“The design and construction of tree-shaped and
fare-faced concrete buildings” Concrete Journal, Vol.
43, No. 6, 2005.
45. Mogami, I., Tsurutani, I., Omura, T. and Kanda, K.
“Large scale seismic isolation retrofit while
maintaining full operations considering construction
safety and inconvenience” Concrete Journal, Vol. 42,
No. 10, 2004.
46. Maruya, T., Sakamoto, J., Shimada, M. and Sakama,
S. “Repairing design and construction of wastewater
storage tank which is exposed to high temperature
with self-compacting concrete (in Japanese)”
Concrete Journal, Vol. 36, No.9, 1998, pp.35-38.
47. Nakamura, K. and Funakosi, N. “An
earthquake-resistant reinforcement of block arched
bridge with high-flowed-concrete construction (in
Japanese)” Proceedings of Annual Conference of the
Japan Society of Civil Engineers, Vol. 57, No. 4,
2002, pp.309-310.
48. Ikeda, K., Daibuzono, K., Okada, S. and Nishimoto,
Y. “Filling method by pump for under side of
cantilever slab with high fluidity concrete (in
Japanese)” Concrete Journal, Vol. 38, No.10, 2000,
pp.35-40.
49. Uno, Y. “State-of-the art report on concrete products
made of SCC” Proceedings of the International
Workshop on Self-Compacting Concrete, Mar., 1999,
pp.262-291.
50. Takagi, S., Komatsubara, T., Tsutsumi, Y., Yokota,
K. and Kaburagi, T. “Construction works of high
water resistance cylindrical diaphragm wall by using
high strength and super workable concrete –the
construction project of TP1 LPG underground
storage tank- (in Japanese)” Concrete Journal, Vol.
34, No.12, 1996, pp.26-29.
51. Inoue, H., Takeichi, Y. and Ohtomo, T.
“Construction of rigid foundation of underground
diaphragm walls with highly congested reinforcing
bar arrangement using self-compacting concrete,”
Proceedings of the Second International Symposium
on Self-Compacting Concrete, 2002, pp.643-650.
52. Muranaka, T., Kishimoto, T., Koyama, F. and Yokoi,
K. “Construction of ventilating shaft on Jonanjima
Side in Tokyo Harbor Seaside-way –project of
submerged tunnels at Tokyo West Fairway- (in
Japanese)” Concrete Journal, Vol. 36, No. 5, 1998,
pp.17-21.
53. Fujita, M., Uyama, S., Kushigemachi, H.,
Morokado, M., Sshinkai, C. and Chikamatsu, R.,
“Application of low heat type highly flowable
concrete to water purification plant with a concrete
volume up to 200,000 m3 (in Japanese)” Proceedings
of the Japan Society of Civil Engineers, V, Vol. 39,
1998, pp.147-154.
54. Fukawa, Y., et al. “Rapid concreting into base
structure of vertical shaft for storm water storage
tunnel by low-heat type highly flowable concrete (in
Japanese)” Proceedings of the JSCE Symposium on
SCC, 1996, pp.175-180.
55. Ojima, R., Jodai, T., Nakashima, Y., and Kozawa, K.
“Pouring works of high fluidity concrete for Kobe
Port Minatojima Tunnel (in Japanese)” Concrete
Journal, Japan Concrete Institute, Vol. 34, No. 8, Jun.,
2006, pp.21-28.
56. Sakai, M., Okazawa, Y., Akai, S. and Yasuda, T.
“Construction of a thin secondary tunnel lining
which uses self-compacting concrete containing an
expansive additive -Nagasaki Expressway, Nagasaki
Tunnel- (in Japanese)” Concrete Journal, Vol. 41,
No. 7, 2003, pp.41-26.
57. Takeshita, H., Tada, S., Sahara H., Shoji, Y. and
Tanaka, M. “Application of super flowing concrete
to secondary lining shield tunnel -Part 2: results of
execution (in Japanese)” Proceedings of Annual
Conference of the Japan Society of Civil Engineers,”
Vol. 48, No. 6, 1993, pp.206-207.
91
Keynote Lecture
8th International Symposium on
Utilization of High-Strength and High-Performance Concrete
... The use of SCC in construction engineering not only leads to the shortening of construction time and the reduction of labor cost, but also lowers the noise and the vibration level on the building site (Nunes et al. 2006). Due to these advantages of SCC materials over normal vibrated concrete, SCC had been widely applied in large-scale buildings, high-speed roads, cross-ocean bridges, dams, and marine structures (Ouchi 2001). ...
Article
Full-text available
Nowadays, utilizing large amount industrial by-product fly ash (FA) as the alternatives for cement in self-compacting concrete (SCC) had attracted more attention. In this study, FA was employed in SCC at five levels (0 %, 20 %, 30 %, 40 %, 50 %). The mechanical behaviors, the water porosities, the transport properties, and the sustainability of FA series SCC were investigated. At the initial curing stage (3 days), the use of FA in SCC reduces mechanical properties and increases water porosity, water absorption and water absorption coefficient (sorptivity) of SCC. FA series SCC have the lower resistance against carbon dioxide attack and chloride ion penetration than cement-based SCC. The prolonging curing time is beneficial to improve the long-term behaviors of FA- blended SCC. After SCC made by 20 %, 30 %, and 40 % FA water-curing for 90 days, there are the reduction of 0.44–2.09 % in the mechanical behaviors and the increase of 0.082–0.41 % in the water porosity, compared to pure-cement SCC. Beyond the content of FA (40 %), the differences of the mechanical properties and the water porosity between SCC with 50 % FA and fully cement SCC are below the value of 2.5 %. With the progress in the curing time, the largest reduction rates of the water absorption and the sorptivity in all SCC mixtures were found in 50 % FA-blended SCC. Utilizing 50 % FA in SCC reduces the total charge passed values of SCC. The manufacture of 50 % FA-blended SCC has the lowest energy consumption and released amounts of CO2, NOx, and SOx in all series SCC mixtures. The application of high-level FA to SCC is the positive assistance to prepare sustainable SCC with satisfying long-term behaviors.
... The use of SCC in construction engineerings not only leads to the shortening of construction time and the reduction of labor cost, but also lowers the noise and the vibration levels on the building site (Nunes et al. 2006). Due to these advantages of SCC materials over normal vibrated concrete, SCC had been widely applied in large-scale buildings, high-speed roads, cross-ocean bridges, dams and marine structures (Ouchi 2001). ...
Preprint
Full-text available
Nowadays, utilizing large amount industrial by-product fly ash (FA) as the alternatives for cement in self-compacting concrete (SCC) had attracted more attention. In this study, FA was employed in SCC at five levels (0 %, 20 %, 30 %, 40 %, 50 %). The mechanical behaviors, the water porosity, the transport properties and the sustainability of FA series SCC were investigated. At the initial curing stage (3 days), the use of FA in SCC reduces mechanical properties, increases water porosity, water absorption and water absorption coefficient (sorptivity) of SCC. FA series SCC have the lower resistance against carbon dioxide attack, chloride ion penetration than cement -based SCC. The prolonging curing time is beneficial to improve the long-term behaviors of FA- blended SCC. After SCC made with 20 %, 30 %, 40 % FA water-curing for 90 days, there are an reduction of 0.44-2.09 % in the mechanical behaviors and an increase of 0.082-0.41 % in the water porosity, compared to pure-cement SCC. Beyond the content of FA (40 %), the differences of the mechanical properties and the water porosity between SCC with 50 % FA and fully cement SCC are below the value of 2.5 %. With the progress of the curing time, the largest reduction rates of the water absorption and the sorptivity were found in 50 % FA-blended SCC. Utilizing 50 % FA in SCC reduces the total charge passed values of SCC. The manufacture of 50 % FA-blended SCC has the lowest energy consumption and released amounts of CO 2 , NO x , SO x in all SCC mixtures. The application of high-level FA in SCC is the positive assistance to prepare sustainable SCC with satisfying long-term behaviors.
... Similarly at construction sites, the savings in fuel such as diesel consumed by concrete pumps can be significant by using SCC instead of CVC. Fig 3 depicts the reduction in pumping presssure as observed for horizontal pumping [5]. Figure.3. ...
Article
Full-text available
The paper describes how two traditional construction materials-Concrete and Steel Reinforcement can contribute better value to RCC and Precast Concrete structures by modernizing their forms as Self-Compacting Concrete (SCC) and Welded Wire Fabric (WWF). SCC is widely accepted by infrastructural, industrial, commercial and even individual house builders – due to its assured quality delivery, especially for cast–in-situ RCC construction. Many defects with conventional vibrated concrete -- honeycombing, segregation and bleeding, loss of workability, choking in concrete pump pipelines and overheating -- have been eliminated or at least minimized by using SCC. For any type of congested reinforcement, mainly in beam – column junctions, edges and corners, SCC has delivered satisfactory filling and honeycomb free densification. Also due to the absence of the use of vibrators, formworks have been spared from joint leakages – saving both the concrete and the formwork itself. But however, even in many advanced construction companies, due to poor detailing practices, and non-mechanized bar-bending (or mechanization limited to only cutting and bending of rebars ), reinforcement laps, splices and bends, hooks, pose an additional burden on the free flow, filling and densification of SCC. Thus using SCC alone may not ensure defect free construction in RCC. The changes should be wholesome and comprehensive. This paper describes how SCC and WWF enhance the quality of RCC construction and ensuring defect free construction. The effects of WWF and SCC are elaborated in detail considering all the physical properties and practical issues. Along with the technical analysis, the commercial and sustainable benefits of SCC and WWF are discussed.
... Self-compacting concrete (SCC) is usually characterized as a high-performance concrete that can pass through the gaps between steel bars and fill the formwork completely, only relying on its own gravity during pouring process [1][2][3]. It is distinguished by excellent workability; thus, no vibration is required during casting, which can significantly reduce the cost, simplify the protocol, shorten the construction time, and guarantee the homogeneity of concrete, especially when applied to the complex cross-section structures [4,5]. Owing to those advantages, increasing attention has been paid to SCC since it was first prepared in 1988 [6]. ...
Article
Full-text available
This study explores the effects of metakaolin (MK) and silica fume (SF) on rheological behaviors and microstructure of self-compacting concrete (SCC). The rheology, slump flow, V-funnel, segregation degree (SA), and compressive strength of SCC are investigated. Microstructure characteristics, including hydration product and pore structure, are also studied. The results show that adding MK and SF instead of 4%, 6% and 8% fly ash (FA) reduces flowability of SCC; this is due to the fact that the specific surface area of MK and SF is larger than FA, and the total water demand increases as a result. However, the flowability increases when replacement ratio is 2%, as the small MK and SF particles will fill in the interstitial space of mixture and more free water is released. The fluidity, slump flow, and SA decrease linearly with the increase of yield stress. The total amount of SF and MK should be no more than 6% to meet the requirement of self-compacting. Adding MK or SF to SCC results in more hydration products, less Ca(OH)2 and refinement of pore structure, leading to obvious strength and durability improvements. When the total dosage of MK and SF admixture is 6%, these beneficial effects on workability, mechanical performance, and microstructure are more significant when SF and MK are applied together.
... The self-compacting concrete is different from controlled self-compacting concrete due to its characteristics i.e. a) it flows under its own weight and due to which it can easily flow over the congested reinforcement, b) it does not require vibrations, c) it makes the homogeneous paste with sand and aggregates without undergoing the segregation. Self-Compacting Concrete is a future concrete for construction work to enhance the strength and workability of SCC [1] . The Utilization of Waste materials such as Fly Ash, Rice Husk Ash, and GGBS etc. [2] have been used by the researchers to enhance the properties of SCC and concluded that using these wastes as a partial replacement of cement in Self-Compacting Concrete is useful to get the desire results expected from the experimental study. ...
Article
Sugarcane Bagasse Ash is a waste bio-product from agricultural and industrial waste obtained from sugar mill by extracting all the valuable sugar from it and after burning bagasse under certain temperature. In this study agricultural waste Sugarcane Bagasse Ash (SCBA) is used as a supplementary material for Self-Compacting Concrete in different proportions as 0%, 5%, 10%, 15%, 20% and 25%. The fresh, mechanical, durability and microstructure properties of treated and controlled self-compacting concrete is evaluated. The test results indicate that 10% of Sugar cane Bagasse Ash with cement is the optimum percentage to obtain the efficient self-compacting concrete and utilization of bagasse ash will lead to greener self-compacting concrete.
... In the construction industry, self-compacting concrete (SCC) has been increasingly used in ready-mix concrete and in the precast industry due to its technical advantages and to improve several aspects of construction [16,17]. The specific formulation of these concretes related to their implementation requirements could affect their mechanical behavior in the hardened state, compared to traditional vibrated concrete [18]. ...
Article
Until now, there are few studies on the effect of mineral admixtures on correlation between compressive strength and ultrasonic pulse velocity for concrete. The aim of this work is to study the effect of mineral admixture available in Algeria such as limestone powder, granulated slag and natural pozzolana on the correlation between compressive strength and corresponding ultrasonic pulse velocity for self-compacting concrete (SCC). Compressive strength and ultrasonic pulse velocity (UPV) were determined for four different SCC (with and without mineral admixture) at the 3, 7, 28 and 90 day curing period. The results of this study showed that it is possible to develop a good correlation relationship between the compressive strength and the corresponding ultrasonic pulse velocity for all SCC studied in this research and all the relationships had exponential form. However, constants were different for each mineral admixture type; where, the best correlation was found in the case of SCC with granulated slag (R2 = 0.85). Unlike the SCC with pozzolana, which have the lowest correlation coefficient (R2 = 0.69).
Article
Full-text available
Where the placing and compaction of concrete are difficult (such as structural element jacking, filling near retaining structure) self-compacting concrete play a vital role in these condition. Self-compacting concrete (SCC) is widely used where the ability of flow and self-compaction is required. Main benefit of these concrete (SCC) is to save labour cost and minimize the construction time. In the view of materials, there is slightly different from commonly used material for construction. The coarse aggregate used in SCC is taken less i.e. up to 50 per cent. Bagasse ash is used as a partial replacement for cement. The research work is done, by considering the variation of water cement ration from 0.25 to 0.35 and the percentage of bagasse ash varies from 10 to 20 per cent. For defining the flow-ability of SCC slump test, V –funnel, U-box test and L- box test had conducted. The value of horizontal slump flow varies from 560 to 760 mm. The flow time in V- funnel test varies from 8 to 12 second is taken satisfactory.When the bagasse ash is used up to limited range from 10 to 20 per cent slump flow gradually decreases but when super plasticizer is used there will be improvement in slump flow. By the use of bagasse ash the compressive strength will also increase at lower w/c ration 0.275 and with 15% bagasse ash. When we further increase in the bagasse ash per cent there is very less increase in compressive strength.
Chapter
Full-text available
Ready mixed concrete (RMC) is a composite material produced to achieve required properties by mixing quantity of constituents with the aid of computer control in batching plant. Then, it is delivered to consumers in fresh state. In case that ordinary RMC cannot provide the required properties for specific purposes or uses, special types of RMCs which can be called as value added products (VAPs) are produced. These special products show differences in terms of their constituent materials and amounts, properties and application areas. VAPs have special properties to overcome some difficult problems faced during concreting operations. Therefore, they can require to use some materials other than main constituents of concrete. Chemical admixtures are also utilized in order to improve or modify fresh and hardened properties of VAPs.
Chapter
The improvement and development of new techniques in material science are progressively rapid. An experimental programme was conducted to assess the influence of addition of steel fibres to self-compacting concrete (SCC). The aim of present experimental work is to study the effect of superplasticizer and steel fibres on the properties of fresh and hardened SCC. Based on the properties of constituent materials, various trials mixes were produced by varying material proportions, w/c ratio and superplasticizer dosage. An optimum mix design satisfying all requirements of SCC was obtained. Steel fibres of varying percentages from 0 to 5% were added to optimum mix to carry out study on the properties of fresh and hardened SCC. Slump flow, V-funnel and L-Box tests were conducted to study the properties of fresh SCC. Cubes and cylinders were cast cured for 28 days and tested for compressive strength and split tensile strength to study the properties of hardened SCC. The results obtained indicate a direct impact of dosage of superplasticizer and percentage content of fibres on the properties of fresh and hardened SCC.
Article
A steel-concrete-steel sandwich structural design is being used for the immersed tube sections of the Kobe port Minatojima Tunnel. The first pouring works of high fluidity concrete in the main assemblies are finished. Various factors affect the quality of high fluidity concrete, and also it is impossible to confirm directly the filling and to repair the failure, pouring concrete into sandwich steel cell. For success of pouring works, we made methods about the accurate quality control and the exact logistics of concrete. This report describes the methods and results of the quality control, the logistics and the non destructive inspection with regard to the first pouring works into the sandwich steel cell.
Article
In this technical report outline of the first application, in Japan, of the ultra highstrength concrete with design strength of 600 kgf/cm2 using silica fume to a super high-rise building is presented.The structure of the 39 story building is a steel frame with steel tube colums filled with the ultra high-strength concrete. The concrete was pumped into the columns from the bottom up to 61.9 m at a time. For the production of the silica fume concrete, a ready mixed concrete plant that enables the use of as-produced silica fume was developed. Trial mixing tests, pumping tests and bottom-up concreting tests were carried out before construction. The outline of the plant and the results of the actual construction are presented along with the preliminary tests.
Article
It was found that the self-compacting concrete added with the slowly cooled blast furnace slag powder has a better property of fluidity retention than the self-compacting concrete added with the granulated blast furnace slag powder or the lime stone powder. As for the mortar added with slowly cooled blast furnace slag powder, the greater the Blaine specific surface is, the better the fluidity retention is obtained. The fluidity retention mechanism of the ordinary portland cement - slowly cooled blast furnace slag powder system was shown to be resulted from that the initial hydration of C3A is suppressed by the thio-sulphate ion released from the slowly cooled blast furnace slag powder
Article
大規模な水槽を有する高度浄水施設の築造において, 水密性の確保, 施工性の向上ならびに施工環境の改善を目的として, 打設総量が約20万m3に達する大量の高流動コンクリートを適用した. この高流動コンクリートは, マスコンクリートのひび割れ制御対策として, 低熱ポルトランドセメントを用いて低発熱化を図るとともに, 特に高い水密性が要求される部材には, 膨張材を併用して硬化後の収縮が低減されるように配慮した. 本報告は, 低発熱型高流動コンクリートの材料および配合選定, レディーミクストコンクリート工場での製造管理および実施工時の品質管理結果などについてまとめたものである.
Article
This paper summarizes the relation between the molecular structure and the dispersion-adsorption mechanisms of 3 types of comb-type superplasticizers used in Japan. The action mechanisms of comb-type superplasticizers and the compatibility of cements and superplasticizers are influenced by the molecular structure of polymers such as copolymer components and the grafted chain length of poly (ethylene-oxide) (PEO). Many reports regarding concrete research have investigated the influence of comb-type superplasticizers on the fluidity of concrete and the production of selfcompacting concrete. However, many have not considered the effect of the molecular structures of comb-type superplasticizers. This paper should be useful for engineers and researches studying the action of comb-type superplasticizers in the production of concrete with comb-type superplasticizers, and for understanding any new properties of such concrete.