Full Scale Processing Investigation for ECC Pre-cast Structural Element

Tetsushi Kanda*1, Shiro Tomoe2, Satoru Nagai2, Makoto Maruta1, Toshiyuki Kanakubo3
and Katsuyuki Shimizu4
1

Supervisory Research Engineer, Kajima Technical Research Institute, Japan
2
Senior Research Engineer, Kajima Technical Research Institute, Japan
3
Associate Professor, GSSIE, University of Tsukuba, Japan
4
Graduate Student, GSSIE, University of Tsukuba, Japan

Abstract
ECC is a pseudo-strain-hardening, highly ductile cementitious composite. However, the major studies on
this material have been limited to laboratory scale without experience in full-scale plants. Thus, practicalapplications of ECC have not been previously investigated. In the current study, full-scale processing
experiments were executed, and mechanical and fresh properties were tested, where emphasis was placedon two types of tensile test. It was thus proven that ECC can provide excellent fresh and mechanicalproperties in full scale production, and a statistical basis for determining tensile property speciﬁcations wasprovided. Furthermore, it was found that ﬂexural tests can be utilized for inspecting tensile properties indaily production. These experimental data were reﬂected in an actual building construction project that was
designed to utilize ECC structural elements. As a result, ECC element production was successfully achieved
with the required quality in this project.
Keywords: ﬁber; cement composite; tensile property; full scale production; structural application

1. Introduction
Engineered Cementitious Composite, ECC, isa pseudo-strain-hardening ductile cementitious
composite 1 ) . Pseudo-strain-hardening behavior
is characterized in tensile stress-strain relation
where stress increases gradually under large strain
development. This new material exhibits a maximum
tensile strain of several percent owing to the synergetic
effect of high-performance polymer fiber andspecifically designed mortar matrix. Unprecedented
high-performance structural members can be expected
when ECC is applied to seismic components2).
However, the large number of worldwide studies
on ECC presented so far have been limited tolaboratory scale without experiences in full-scale
plants. Production technology also lacks knowledge ofperformance standards necessary for designing ECC
members; there have been insufﬁcient discussions on
how to refer to the design standard on tensile properties
or how to control the material processing in actual
construction. These problems have been the principal*Contact Author: Tetsushi Kanda, Supervisory ResearchEngineer, Kajima Technical Research Institute, 2-19-1
Tobitakyu, Chofu-shi, Tokyo 182-0036, Japan
Tel: +81-424-89-7074 Fax: +81-424-89-7185
e-mail: kandat@kajima.com( Received April 17, 2006 ; accepted July 5, 2006 )obstacle to practical applications and needed to bequickly resolved.
This paper describes the full-scale production of selfcompacting ECC with PVA fiber3),4), and shows that
quality assurance of fresh and mechanical properties of
ECC in the plant is highly reliable, and that its tensile
properties can be veriﬁed by a simple test. A statisticalevaluation of tensile properties and knowledge ofperformance standards indispensable to the design of
ECC structural members are presented. Two types oftensile test were executed, and the characteristics andmechanical performance under tension are discussed.
The applicability of the tensile property control by aﬂexural test in production is proposed in comparison
with the tensile tests. These experimental data arereflected in an actual building construction projectthat is designed to utilize ECC structural elements.
ECC element production is shown to be successfully
achieved with the required quality in this project.
2. Experiment
2.1 Objectives and test parameters
ECC production has been poorly documented except
for a few reports on a full-scale mixing test 4). This
study aims to obtain knowledge on quality assurance
in full-scale production by a trial production in pre-cast
concrete plants on a large scale.
The test items and parameters are shown in Table
1. and their combination is shown in Table 2. These

Journal of Asian Architecture and Building Engineering/November 2006/340

333

Table 1. Outline of Experiment

Table 2. Test Items and Parameters

Fig.1. Tensile Test of
Plate Specimen (TC Test)

Table 3. Mix Proportions

Table 4. Testing Method

experiments were executed in two pre-cast concrete
plants equipped with Omni mixers with a capacity of
1 m3 and 0.5 m3. Batches of 0.8 m3 and 0.4 m3 weremixed, and the total of 15 mixes were subjected to
fresh and mechanical property tests as shown in Table
2. Types of cement, ambient temperatures (in plant) at
production and pre-cast concrete plants were varied.
Ordinary portland cement (OPC) and moderate-heat
portland cement (MPC) were used. OPC was a major
cement type in this experiment while MPC was also
examined for its better ﬂuidity.
Examination of the ambient temperature isnecessary for stable ECC production without regard
to season. Experiments were executed in spring (May,temperature 17 to 20°C) and in winter (November,
temperature 9 to 16°C). The pre-cast concrete plants
were located in the Kanto area (near Tokyo) and the

334 JAABE vol.5 no.2 November 2006

Fig.2. Tensile Test ofPrism Specimen (TP Test)

Tokai area (near Nagoya), and are hereafter denoted as
Plant 1 and Plant 2, respectively. The material suppliers
and manufacturers, and a lot of the major raw materials
such as cement, aggregate and ﬂy-ash for the two plants
differed. The cement manufacturer was the same but
the cement lots used in each plant were uncontrolled.
Fly-ash products used were type II, as speciﬁed in theJapanese Industrial Standard (JIS) A 6202 and they
were stored in each plant. However, their original
power plants were different and hence their properties
were subjected to change. The aggregates used in eachplant came from different areas. The air content varied
from 6 to 14 percent, a controllable manufacturing
range, with an air-entraining agent. This was done todetermine the effects of air content variation on the
fresh state and the mechanical properties, although thedesigned air content was 10 percent.
2.2 Mix proportions
The mix proportions used in this study are shownin Table 3., where Mix-N is based on the literature4)
and the Mix-M is nearly the same as Mix-N except forthe substitution of OPC with MPC. These two mixes
showed self-compacting fresh properties in laboratory
mixing 3) , and slump flow values of over 500mm.
A CSA-type expansive agent and an alcohol-type
shrinkage reducing agent were admixed with each mix
assuming a large unit water content.
A bio-saccharide-type viscous agent was also
applied to provide compatibility between ﬂuidity andﬁber dispersibility. In addition, a polycarboxylic-acidbased superplasticizer was simultaneously used. The
ﬁber was PVA with a length of 12 mm, a diameter of
0.04 mm, tensile strength of 1690 MPa and an elastic
modulus of 40,600 MPa.
2.3 Test items
The test items and methods are listed in Table 4.
Fresh properties and compressive tests were based on
the standard method specified in JIS while uniaxial
tensile tests were based on two methods tentatively

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proposed in the past because there is no standard
method. The flexural test follows a newly proposed
standard, JCI-S-003-2005. Specimens were subjectedto the fresh performance test immediately after mixing
and to the compressive and tensile tests after steam
curing of 35°C-8 hours and subsequent sealed curingof 20°C-28 days.
The two tensile tests have distinct features. In the
TC tensile test5), a plate shaped specimen is directly
supported by pneumatic chucks and subjected totensile loads with hinge or ﬁxed boundary conditions
as shown in Fig.1. This method is easy to execute,
can deal with a number of specimens in a limited
time and has large accumulation of past records.
However, it has been pointed out that test results haveoften shown considerable scatter probably becauseof the difficulty to precisely align the loading axis
with the specimen center axis. It is also pointed outthat the thin plate-shaped specimen section is likely
to cause 2-dimensional fiber orientation, resulting inoverestimate of tensile properties.
The TP tensile tester in Table 4. is an improved
version of the TC tester4),6). As seen in Fig.2., a larger
specimen with a cross section of 60 x 100 mm wasused to eliminate the 2-dimensional fiber orientation(refer to literature vi for more detail) and was expected
to provide a more precise tensile performance of ECC
in a structure. The TP tester can also use hinge or ﬁxed
boundary conditions, but its chucking mechanism isdifferent from that of the TC tester. A steel rod ﬁxed
to a plate bonded to a specimen is directly chucked by
the compression tester to ensure precise matching of
the two axes. However, the TP test requires a larger
specimen and hence longer preparation time than the
TC test, making it difﬁcult to adapt to a quality control
routine test in the production of ECC components.
This study aimed to obtain a tensile performance of
ECC necessary for full-scale production by statisticalanalysis of the test results obtained from two different
test methods. The tensile performance results wereexpressed in terms of two parameters: tensile strengthand ultimate tensile strain. The tensile strength is the
maximum stress obtained in a test and the ultimate
tensile strain is the point where stress begins todecrease continuously with increase in strain. Morethan five specimens were tested in each batch anddata of a minimum of three specimens, excluding thehighest and lowest values, were subjected to analysis.
The ﬂexural test is a modiﬁed version of the normal
bending test, newly published in JCI-S-003-2005 7).
The test method is outlined in Fig.3. Specimens withdimensions of 100 x 100 x 400 mm were subjected to
3-point equivalent loading. Strains at two points in thecentral ﬂexural zone of 100 mm were measured, andthe ﬂexural curvatures calculated with the strains wererecorded with the corresponding loads.

JAABE vol.5 no.2 November 2006

3. Tensile Performance Prediction
This study aims at applying the flexural test
to the quality control of tensile performance of
ECC components at the manufacturing process
and at establishing a method for predicting tensile
performance from ﬂexural test results. The prediction
method originally proposed by Kanakubo et al.8),9) is
to predict ultimate tensile strain εu and tensile strength
σmax from the maximum moment point in the momentcurvature relation obtained from a flexural test. This
study introduces conversion factors to calibrate ﬂexural
test results with those in TP tests as follows.

where D is the height (mm), E is the elastic modulus
of ECC (N/mm2), φu is the curvature at the maximum
moment determined by ﬂexural test, and αs and αe are
the conversion factors of strength and ultimate strain
respectively, which are newly introduced in this study.
xn1 can be obtained from the relation between measured
load and curvature and is a solution to the following
equations (3) and (4). M max in equation (3) is the
maximum moment by experiments, and B is the widthof a specimen.

Equations (1)-(4) are derived on the assumption thatthe stress and strain distributions shown in Fig.4. form
within the cross section of a specimen under ﬂexure6),i.e., modeled in triangular distribution for compressive
stress and uniform distribution for tensile stress (xn1=xn/
D). To ensure this tensile stress distribution, the ECC
stress-strain relation was assumed to behave as perfectelasto-plastic type.
It is important to note that the α s and α e values
may vary according to the material properties, sizeof the flexural test specimen and loading conditions.
This dependency originates from the fact that ﬂexural
performance is a structural performance strongly
sensitive to specimen size and loading conditions
while tensile performance by nature can be regarded
as a material property10). Thus, the prediction of tensile
performance by means of a flexural test should beexecuted with special care of the targeted materials,
and the values of αs and αe may vary depending on
the flexural test conditions. At the present technicallevels, the conversion factors αs and αe may not bederived theoretically and may be reasonably treated as
experimental parameters. This study aims at obtaining

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335

these conversion factors by comparing the ﬂexural andtensile test results.
4. Experimental Results
4.1 Mixing and fresh properties
Mixing was executed with an Omni mixer as shownin Fig.5., and the resulting fresh properties are shownin Table 5. The air contents of the fresh mortar ranged
from 6 to 14 percent as expected. Flow values weregenerally more than 500 mm, thus demonstrating
excellent ﬂuidity. The casting process necessitated novibrators in the form. No distinct changes in fluidity
were observed with different air contents, showing thatthe effects on ﬁber dispersion were small.
The effects of ambient temperatures and cement
type were found to be small in this experiment, which may
be attributed mainly to the use of hot water of 30°C for
the mixing in winter at Plant 1. Consequently, the fresh
temperatures immediately after mixing varied little withthe season, so that the ﬂuidity and the ﬁber dispersion
exhibited no differences. It was confirmed thatspecial care with the mixing water temperature andhence control of the mixed temperatures led to stablefresh and hardened properties. When the ambient
temperatures exceed 30°C, which did not occur in thisexperiment, the fluidity of the N-mix is expected todecrease. For this case, M-mix may be recommended.
Fresh properties obtained from the two
manufacturing plants varied. Significantly poor fresh
properties were observed in the N-mix of Plant 2(P2N1), where the slump flow was lower than 400
mm, showing much lower fluidity than those of theother mixes. The fresh properties of M-mixes from thetwo plants were similar. Thus, the reason for the poor

Fig.3. Flexural Test

Table 5. Test Results of Fresh Properties

Table 6. Test Results of Mechanical Properties

Fig.4. Assumed Stress and Strain Distribution

Fig.6. Tensile Test Result (TC Test)

336 JAABE vol.5 no.2 November 2006

Fig.7. Tensile Test Result (TP Test)

Fig.5. Omni Mixer Outside View

Fig.8. Flexural Test Result

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Table 7. Summary of Experimental Parameter Effects(a) Ultimate tensile strain(b) Tensile strength

Fig.9. Effect of Air Content (TP Test)

Fig.10. Comparison of Tensile Tests

Fig.11. Flexural Analysis
Application

fluidity in P2N1 has not been identified. However,it may be due to an inappropriate combination of
constitutive material products, e.g., cement, fly ash,viscous agent, and superplasticizer. This result implies
the importance of initial checking of constitutive
material combination by trial mixing. As a result, it
is still indispensable for ECC to execute test mixings
prior to manufacture because variations in properties
are sure to occur in different plants.
4.2 Mechanical properties
A series of test results of mechanical performanceare shown in Table 6., including mean values ofcompressive strength and elastic modulus. All therecorded values are the means of the measured valuesof three specimens. As shown in Table 6., compressive
strength and elastic modulus ranged from 24.0 to
37.4 MPa and 12.3 to 17.2 GPa, respectively, thus
demonstrating considerable variation by batch.
Tensile stress-strain curves obtained from TC
and TP tests (P1N6) are shown in Fig.6. and Fig.7.,
respectively. Both TC and TP test results clearly
indicate pseudo-strain-hardening characteristics,
where stress increases gradually under large strain
development. Mean values of tensile performance bybatch are also shown in Table 6. It is shown that theresults of the TC tests were generally greater than thoseof TP tests.
Results of ﬂexural tests are shown as a relationshipbetween flexural stresses and curvatures in Fig.8.
The deflection-hardening characteristics are clearly
exhibited; early-stage elastic behavior is followed
by stiffness reduction due to cracks, and in the laterstages, resistance to applied loads is maintained atlarge ﬂexural curvatures.

JAABE vol.5 no.2 November 2006

Table 8. Statistical Data of Tensile Properties

5. Discussion of Experimental Results
5.1 Effects of experimental parameters
Effects of ambient temperature, cement type anddifference in plant on mechanical properties of ECC
are shown in Table 7., where the mechanical propertiesare represented by the mean of all specimens. It is seenin Table 7. that the effects of ambient temperature were
small and that stable mechanical performance can beachieved with control of mixing temperatures within
the temperature range of this experiment.
As seen in Table 7., compressive and tensile strengthof N-mix with OPC are both 10 to 15 percent greaterthan those of M-mix. This is reasonable because thehydration rate of MPC is less than that of OPC, while
the effect of cement type on the ultimate tensile strain
is generally small in this experiment.
The different mechanical properties obtained fromthe two manufacturing plants are shown in Table 7.
The ECC produced in plant 2 shows 20 to 30 percent
lower compressive strength, tensile strength, andelastic modulus than that in plant 1. This leads to lower
fracture toughness of the mortar matrix in plant 2 thanthat produced in plant 1 and agrees closely with thelarger ultimate strain observed in the experiments. The
different mechanical responses of ECC from the twoplants are still unclear from the experiment, but thereactivity of the ﬂy-ash is a possible cause.
5.2 Effects of air content variations
Effects of air content on tensile properties obtained in
the TP tests are shown in Fig.9. Fig.9.(a) demonstrates
rather weak correlation between ultimate tensile strain
and air content, showing a correlation coefficient ofless than 0.4. Furthermore, variation in air content
appears to show negligible effects on ultimate tensile
strain. Similar trends are found in tensile strength, asshown in Fig.9.(b), while the correlation coefﬁcient islarger than for tensile strain capacity. The results in TC

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337

test show similar weak correlation and inﬂuence withdifferent air content levels. As a result, the effect of aircontent on ultimate tensile strain and tensile strengthappears to be negligible.
5.3 Statistical evaluation and specified designmaterial properties
Statistical data of tensile performance in the TP test
are shown in Table 8. This test is regarded to represent
the behavior of the ECC component, where speciﬁedmaterial properties applied in design can be obtained.
The ultimate tensile strain and its lower limit allowed
a 4-percent defective for 3 mixes, N and M mix inplant 1 and M mix in plant 2, are listed in this table. As
shown in this table, the lower limit of ultimate tensile
strain for each mix is approximately one percent.
Furthermore, the lower limit of tensile strength for eachmix is approximately 3 MPa. Because the lower limit
represents a material performance that can be assured,
speciﬁed material properties of ECC manufactured inthis study can be set as one percent for the ultimate
tensile strain and 3 MPa for the tensile strength.
It should be noted that ECC tensile mechanicalproperties tend to exhibit rather strong size effects,
as demonstrated in Fig.10. and explained in the next
section. However, research results in the literatureshow that tensile mechanical properties obtained fromTP tests can be utilized to predict shear and flexural
performance of structural beam elements 11) while
results of TC tests lead to overestimating of structural
performance12). Hence, the speciﬁed material properties
in the above are considered for the structural design of
ECC elements.
5.4 Quality control of tensile performance
There are two ways to check whether the above
specific material properties are achieved in the
production of ECC members. One is the TC test. In
this study, 6 specimens per hour could be tested in
the TC test, while the maximum for the TP test was 6
specimens per day. Thus, the TC test, which is easy to
execute, is preferable for quality control to the TP test,
which requires considerable time and care, provided
that the mean value for the test is not less than thecontrol value. The applicable range of this quality
control method, however, should be specified taking
account of the difference in the mean and the standard
deviation with respect to the TP test. This difference
is demonstrated in Fig.10., where the TC test exhibits
ultimate tensile strain and tensile strength 1.5 and 1.3
times greater than those of the TP test on average. Thismay be attributed to the size effect of the specimen
and to the fiber orientation in the specimen because
the specimen size was smaller in the TC test. It is also
shown in Fig.10. that the standard deviation of tensile
performance in the TC test was greater than that in
the TP test. This may be attributed to the precisionin aligning the loading axis with the specimen center
axis; precise chucking is possible in the TP test but not

338 JAABE vol.5 no.2 November 2006

Fig.12. Application of ECC Coupling Beam
Table 9. Inspection Outline in Processingin the TC test, where direct pneumatic chucking often
fails to center.
The other possible quality control method is theﬂexural test, which is more realistic than the TC test.
For the ultimate tensile strain and tensile strength,
flexural test data analyzed using Eqs. (1) to (4) arecompared with those of the TP test in Fig.11. In
this analysis of flexural test data, αs and αe were set
to unity for the initial values. It is shown that both
ultimate tensile strain and tensile strength of ECC
can be evaluated on the safe side by multiplying by aconversion factor of 0.7 on the basis of flexural test
and associated analysis. This means that the conversion
factors α e and α s in Eqs. (1) and (2) can be set to
0.7. Taking into account the ease of execution andsimplicity of the apparatus, the ﬂexural test may be themost realistic solution for quality control.
As explained in the previous chapter, theoreticalderivation of the conversion factors is rather difﬁcult
at this moment. A brief remark based on mechanics
is presented as follows. A conversion factor α e for
ultimate tensile strain reflects easier multiple crack
formation under flexure than under tension. Whenthe ultimate ﬂexural load exceeds the initial cracking
load during ﬂexure, an increase in ﬂexural deﬂectionis accompanied by multiple fine cracking between
the loads. This phenomenon is known as deflection
hardening, which is demonstrated in Fig.8. Deﬂection
hardening, although it looks similar to strain hardening
under tension as shown in Fig.6. and Fig.7., occurs
under milder mechanical conditions than strain
hardening. A straightforward example is the analyticalconsequence by Naaman 13) that, when compressive
strength is high enough, the tensile strength of acomposite necessary to show deflection hardening is

Tetsushi Kanda

Fig.13. Slump Flow Inspection Results

Fig.16. Comprehensive Strength Inspection
Results

Fig.14. Air Content Inspection Results

Fig.15. Fresh Temperature Inspection Results

Fig.17. Tensile Strength Inspection
Results

Fig.18. Ultimate Tensile Strain Inspection
Results

one third of the strength of matrix cracking. Whenstrain hardening occurs under tensile loading, thetensile strength of the composite material should
be greater than the matrix cracking strength. It is
important to note the difference between deflection
and strain hardening since multiple cracking occurs
more easily under ﬂexural than under tensile loading.
The conversion factor αe representing the difference inconditions of multiple crack formation in ﬂexure or intension has a meaning that reduces the ultimate strain
predicted from a ﬂexural test.
The other conversion factor α s represents thedifference between tensile stress-strain relations
assuming perfect elasto-plasticity in the derivation of
Eqs. (1)-(4) and reality. As can be seen from Fig.6. andFig.7., the stress-strain relation of ECC can in general
be approximated as bi-linear where stress increases
gradually after initial cracking. The predicted tensile
strength presented in this study was based on theperfect elasto-plastic model and is likely to be greaterthan that obtained in the TP test14), and an error that
may be involved in the assumptions of the stress-strain
relation forms a part of αs.
6. Application in Structural Element
6.1 Outline of application and inspection
Based on the prescribed experimental results,
reinforced ECC structural elements (R/ECC elements,
hereafter) were first applied in building structure asshown in Fig.12. This application utilized R/ECC
in a coupling beam connecting two structural walls
in a 27-story high-rise reinforced concrete building
93m high. The coupling beam was 500mm wide by
900mm high in cross section, and 1650mm long.

JAABE vol.5 no.2 November 2006

Structural features in this application are referred to theliterature15).
These elements were produced one piece per day,for which ECC was mixed with an Omni-mixer inplant 2 as shown in Fig.5. The adopted mix proportions
followed Mix-M shown in Table 3. Production started
in November 2004 and was completed in June 2005.
Element products and specimens for inspection
were steam cured as for the full scale production
experiments, and then cured in a stock ﬁeld for at least
56 days.
The quality inspection process was determined
as shown in Table 9., where lower bounds of tensile
properties were adopted at 2 N/mm2 for strength and
0.5% for ultimate strain, which were identical to thespecific values adopted in the structural design ofthe elements. For safety, these lower bounds wereset for larger variation than that in the results ofTable 8. Tensile properties were inspected by ﬂexural
test and the results in Fig.11. are reflected in thisinspection process. For compressive strength, lower
bound of 36 MPa, which is required from necessity
in structural design, is higher than the results in Table
6. This discrepancy was allowed for by adopting two
operations, a) extending the testing age to 56 days, andb) decreasing the ﬂy-ash weight ratio in the binder to
0.15.
6.2 Results of inspection
In the actual processing, all inspection items weresatisﬁed. The results of fresh property inspection are
depicted in Fig.13., Fig.14., and Fig.15., where all
fresh inspection data are within the specified range.
Mechanical property inspection results are shownin Fig.16., Fig.17., and Fig.18. All mechanical data

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339

satisﬁed the speciﬁcation in Table 9. In the 58 days of
production, the lowest magnitudes were: 36.3 MPa incompressive strength, 2.37 MPa in tensile strength, and
0.59% in ultimate tensile strain.
The lowest compressive strength data were foundclose to the approval limit, as shown in Table 9.,
despite of the prescribed two operations. To decreaserisk, it appears appropriate for future project tofurther extend the test age or to decrease the speciﬁccompressive strength.
Table 10. summarizes the tensile property inspection
results. It shows that the statistical trend of tensile
strength inspection data is similar to that in thefull scale processing experiment shown in Table 8.
However, the mean ultimate tensile strain in Table 10.
is lower than the corresponding value in the full scale
experiment shown in Table 8. This leads to higher
risk of failure to meet the speciﬁcation than expectedfrom the full scale experiment. Major sources of thislower mean value have not been clariﬁed at this stage.
However, possible instability may result from wider
variation in fresh temperature, as shown in Fig.15.
(17-35 deg.), than that described in Table 5. (23.5-32
deg.). Including fresh temperature control, any further
improvement in processing procedure for increasingmaterial reliability is appropriate for future projects.
This improvement operation remains for future study.
7. Conclusion
This study focused on full-scale production of ECC.
First, an extensive full-scale processing experiment
was conducted using actual facilities of pre-castelement manufacturers, where associated ECC
properties were clariﬁed in tests. As a result of the fullscale experiment, it was found that ECC with highmechanical performance and excellent ﬂuidity can beproduced in full scale along with that produced in thelaboratory. The results of this experiment indicatedthat 1 percent ultimate tensile strain and 3 MPa
tensile strength can be achieved with high statisticalconﬁdence based on tensile tests on prism specimens(TP test) that are believed to reﬂect the actual behavior
of ECC components.
Furthermore, tensile performances obtained in theseTP tests were indicated to be reasonably reproduced
using standardized flexural tests. This reproduction
was successfully achieved by introducing a conversion
factor of 0.7 for both tensile strength and ultimate
tensile strain. This conversion factor was identified
from comparison between tensile tests and flexural
Table 10. Tensile Property Inspection Summay

340 JAABE vol.5 no.2 November 2006

tests. As a result, it was shown that ﬂexural tests canbe utilized for ECC's tensile quality inspection inindustrial production.
The above experimental results were fully reﬂected
in determining specifications in applying ECC to ahigh-rise building construction project. This project
facilitated R/ECC coupling beams and is the first
application example of R/ECC structural elements inbuilding structures. Daily fresh test results conﬁrmed
with confidence that inspection data satisfied thespecification. Furthermore, standardized flexural test
data showed that tensile properties in daily production
attained the level required by the specification.
However, tensile property margins for this were lower
than expected and operations to increase confidence
appear necessary for future projects. Discussion on thisimproving operation remains for further study.
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14) Japan Concrete Institute (2004): Technical Committee Reporton the Structural Applications of Highly Ductile Cemetitious
Composites, Chap. 3 (in Japanese).
15) Maruta, M. et al. (2005): New High-Rise RC Structure Using PreCast ECC Coupling Beam, Concrete Journal, 43 (11), pp.18-26 (inJapanese).

Tetsushi Kanda