Buenasa

1. Building application of recycled aggregate concrete for upper-ground
structural elements
Kazuhisa Yoda a,⇑
, Akira Shintani b
a
Kajima Technical Research Institute, Tokyo, Japan
b
Kajima Corporation, Tokyo Architectural Construction Branch, Tokyo, Japan
h i g h l i g h t s
Recycled fine aggregate concrete was first applied to the upper structure of a real building.
Effective technology of producing energy-saving mid-quality recycled aggregate was developed.
New technology of producing high-quality recycled fine aggregate was developed.
Combination of the above two recycled aggregates enables a recycled aggregate concrete applicable to building structures.
a r t i c l e i n f o
Article history:
Available online 3 February 2014
Keywords:
Recycled aggregate concrete
Upper structure
On-site application
Low environment impact
Durability
a b s t r a c t
Application of the recycled aggregate is a promising technology for resource saving and low environmen-
tal impacts, which is more effectively performed when recycled fine aggregate is used in addition to recy-
cled coarse aggregate. Use of the recycled fine aggregate for the upper structures, however, shows minor
progress because of the trade-off in aggregate quality and emission of fine particles. Two effective tech-
nologies, production of energy saving mid-quality recycled aggregate and high-quality recycled fine
aggregate, presented in this paper enabled the application of the mid-quality recycled aggregate to the
upper structure for the first time in Japan.
Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction
Recycled aggregate concrete is a major technology of reducing
environmental burdens enabling resource saving by recycling the
concrete debris as an aggregate. Particularly in Japan, several pro-
duction technologies capable of manufacturing high-quality recy-
cled course aggregate have been developed and the recycled
course aggregate concretes were applied to the upper structure
of buildings on a trial basis [1,2]. Recycled fine aggregate, however,
requires more production energy than that of the recycled coarse
aggregate to ensure the required quality level when applied to
upper structure of buildings as a part of the recycled aggregate
concrete. Hence it has been mainly used for piles and underground
structures and cases applied to the upper structure of buildings are
few. However, it is still important for the materials flow ensuring
higher recycling rate to establish the application technology of
the recycled fine aggregate for a wider dissemination.
In this context, two technologies including one enabling the use
of mid-quality recycled fine aggregate in the upper structure of
buildings and the other capable of manufacturing high-quality
recycled fine aggregate applicable to nuclear power plant construc-
tions have been developed. The mid-quality recycled fine aggre-
gate, while having a quality inferior to that of the normal fine
aggregate, was used as a recycled aggregate concrete and applied
to the upper structure of a building on a trial basis. This paper
briefly shows the manufacturing technology and the results of
the one-year durability follow-up check of the recycled aggregate
concrete applied to real structure.
2. Technical requirements and solutions
Related Japanese standards for recycled aggregate and recycled
aggregate concrete are shown in Table 1. As a view of the material
flows, it is more efficient to reuse not only recycled coarse aggre-
gate but also recycled fine aggregate. Hence a new technology
capable of using recycled fine aggregate has been developed. Two
major characteristics of the recycled aggregate technology are as
follows.
First, crack control of concrete can be made with the mid-qual-
ity recycled aggregate. The mid-quality recycled aggregate exhibits
advantages including lower manufacturing energy than that of
high-quality recycled aggregate and reduced production of
0950-0618/$ - see front matter Ó 2014 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.conbuildmat.2013.12.096
⇑ Corresponding author. Tel.: +81 424898297; fax: +81 424898442.
E-mail address: yodak@kajima.com (K. Yoda).
Construction and Building Materials 67 (2014) 379–385
Contents lists available at ScienceDirect
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2. by-product powder. However, the major drawback of large drying
shrinkage has limited the application fields to underground con-
struction such as piles. Crack resistance equivalent to that of nor-
mal concrete was attempted using an expansive agent (JIS A
6202 Expansive additive for concrete). Major components of this
admixture comprises calcium-sulphoaluminate-type and lime-
type posing expansive effects due to formation of ettringite and
calcium hydroxide during hydration reactions.
Second, the obtained high-quality recycled aggregate met the
requirements specified in JASS 5N (Japanese Architectural Stan-
dard Specification JASS 5N Reinforced Concrete Work at Nuclear
Power Plants) quality standard. Many aged nuclear power plants
are at the stage of demolition and the reduction and reuse of the
demolished concrete are the urgent task [3]. When rebuild the
nuclear power plants, requirements for the aggregate are very
likely to be in accordance to the JASS 5N quality standard. The
use of the equipment with a rotary drum mill enabled the recy-
cled fine and coarse aggregate satisfying the JASS 5N quality
including absolute dry density, water absorption and grain-size
distribution [4].
3. Experiments on the recycled aggregate and the recycled aggregate concrete
3.1. From experiments to the on-site trial
Procedure from concrete demolition to the on-site application is shown in Fig. 1.
The resource of the recycled aggregate was concrete debris produced when a 31-
year old, 4-storied RC research institute building with a basement built in the same
site was demolished. Properties of the original concrete and its constituent materi-
als are shown in Table 2. The concrete debris was crushed into particles with a
diameter less than 40 mm at an intermediate processing plant and then separated
into high-quality coarse aggregate (hereafter denoted as recycled coarse aggregate
H) and mid-quality fine aggregate (hereafter denoted as recycled fine aggregate M)
with a wet triturator. Further the recycled fine aggregate M was subjected to a ro-
tary drum milling to obtain high-quality recycled fine aggregate (hereafter denoted
as recycled fine aggregate H). These recycled aggregates were used for the recycled
aggregate concrete.
The recycled aggregates and the recycled aggregate concrete were subjected to
material properties test and mock-up experiment to confirm those performance.
Crack resistance was evaluated in terms of penetrating cracks that can be observed
with both embedded strain gauges and visual observation.
3.2. Materials used
Physical properties of aggregate and those of other than aggregate are shown in
Table 3 respectively. Relationship between absolute dry density and water absorp-
tion of typical samples are shown in Fig. 2 and the variation in water absorption by
test is shown in Fig. 3.The recycled coarse and fine aggregates H met the quality
requirements specified in JIS A 5021 and JASS 5N (absolute dry density more than
2.5 g/cm3
, water absorption less than 3.0%) respectively. The recycled fine aggregate
M also met that specified in JIS A 5022 Supplement A (absolute dry density more
than 2.2 g/cm3
, water absorption less than 7.0%). The other materials used are
shown in Table 4.
3.3. Properties of the recycled aggregate concrete
Fresh properties, strength and length change behavior of the recycled aggregate
concrete were studied. The mix proportions of the concrete are shown in Table 5.
The targeted fresh properties were slump of 20 cm and air content of 5.0% taking
into account the possible loss during transportation.
Test results for the fresh properties are shown in Table 6. All mixes met the tar-
geted values of slump (20.0 ± 2.5 cm) and air content (5.0 ± 1.5%) and the workabil-
ity of the concrete was satisfactory. Compressive strength of recycled aggregate
concrete specimens subjected to the standard curing is shown in Fig. 4. When the
water–binder ratio was equal, compressive strength of the specimen was equiva-
lent regardless of the type of aggregate. The length changes until the age of
189 days, according to the restraint method B specified in JIS A 6202 supplement
2 ‘‘Testing method of restrained expansion and shrinkage of concrete with expan-
sive additive’’, are shown in Fig. 5. The length changes showed no differences by
the type of fine aggregate and were able to be reduced approx. 200 lm when an
expansive agent was applied. Effect of the type of fine aggregate on the drying
shrinkage was found to be small compared to that of coarse aggregate and the dry-
ing shrinkage might have not increased significantly if the mid-quality recycled
aggregate was used.
3.4. Evaluation of crack resistance with mock-up test
A mock-up test to confirm crack resistance of mid-quality recycled aggregate
concrete was performed for walls, as shown in Photo 1, made of recycled aggregate
concrete of HMB46 with an expansive agent and of normal aggregate concrete
NNP46 (Table 5) for comparison. The total strains at the center of the wall are
shown in Fig. 6. It was confirmed that the formation of initial crack of HMB46 spec-
imen was largely delayed compared to the normal aggregate concrete proving an
excellent crack resistance of the recycled aggregate concrete.
Table 1
Japanese standards for recycled aggregate and recycled aggregate concrete.
Japanese standard Aggregate Applicable elements
Water absorption of aggregate (%) Quality Consumption energy
Coarse Fine
JASS 5Na
52.0 53.0 Highest Largest All elementsc
JIS A 5021b
53.0 53.5 High Large All elements
JIS A 5022b
55.0 57.0 Middle Middle Only mat, pile, etc.
JIS A 5023b
57.0 513.0 Low Lower Temporary use only
a
Japanese Architectural Standard Specification Reinforced Concrete Work at Nuclear Power Plants.
b
Recycled aggregate standard by quality class.
c
Including those of nuclear power plants.
Fig. 1. Recycling system of recycled aggregate concrete.
380 K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385

3. 4. Application to the construction of the main building of
research laboratory
4.1. Overview
External view of the targeted building is shown in Photo 2. Out-
line of building is shown in Table 7. Before starting the construc-
tion, approval of the Minister of Construction with a limited
validity for the construction was obtained. Types of the recycled
aggregate concrete used in this construction and their applied
parts are shown in Table 8.
Results of slump test performed at the receiving inspection of
the recycled aggregate concrete are shown in Fig. 7. Air content
as well as slump fell within the targeted range. Compressive
strength was also satisfactory as shown in Fig. 8.
Relationship between actual amount of pumping rate and pump
presser loss is shown in Fig. 9. The construction performance of
HHP mix with a high-quality recycled fine aggregate was as good
as that of the normal aggregate concrete NNP while that of HMB
mix with a mid-quality recycled fine aggregate showed an increase
in the hydraulic pressure during pumping. This was attributed to
pressure-induced water absorption of the recycled fine aggregate
and was fixed by compensating the amount of injected water
(HMBW). Due to the addition of water at mixing, the compressive
strength of the specimen sampled at the discharge showed slight
decrease while those sampled at the slurry discharge equivalent
to the strength of the structure was equal to that before the water
compensation.
Appearance of the concrete surface is shown in Photo 3. The
surface of HMB mix looked slight white while those of the other
mixes showed no differences.
4.2. Environmental consequence of the full-scale application
Application of the recycled aggregate concrete to the
upper structure of building contributed to reduction of the
Table 2
Properties of the original concrete and aggregate.
Item Property This study Notes
Original concrete Core Compressive strength (N/mm2
) 31.2 JIS A 1107
Chloride content (kg/m3
) 0.074 JIS A 1154
Original aggregate Coarse aggregate Absolute dry density (g/cm) 2.59 JIS A 1110
Water absorption (%) 1.37
Alkali-silica reactivity No JIS A 1146
Fine Aggregate Absolute dry density (g/cm) 2.50 JIS A 1109
Water absorption (%) 2.74
Alkali-silica reactivity No JIS A 1154
Table 3
Physical properties of aggregate.
Item Class Production method Absolute dry
density (g/cm3
)
Water absorption
(%)
Solid volume for shape
determination (%)
Fine powder (%) F.M.
Coarse aggregatea
Recycled H Wet triturator 2.52 2.35 62.1 0.3 6.80
Crushed store – 2.66 0.39 58.8 0.5 6.64
Fine aggregateb
Recycled H Rotary drum mill 2.52 2.53 61.7 0.9 2.67
Recycled M Wet triturator 2.36 4.94 57.4 1.6 2.75
Pit sand – 2.52 2.37 – 1.4 1.96
Crushed sand – 2.63 1.19 56.1 1.4 2.98
Notes a
1 JIS A 1110, b
2 JIS A 1109 JIS A 1104 JIS A 1103 JIS A 1102
2.2 2.3 2.4 2.5 2.6 2.7
JIS A 5021 class H
Absolute dry density (g/cm3
) Absolute dry density (g/cm3
)
Coarse aggregate
Waterabsorption(%)
14
10
12
8
6
2
4
0
JIS A 5023 class L
JASS5N
Recycled aggregate H
Waterabsorption(%)
2.2 2.3 2.4 2.5 2.6 2.7
Fine aggregate
14
10
12
8
6
0
JIS A 5023 L class
JIS A 5022 class M
JIS A 5021 class H
JASS5N
4
2
Recycled aggregate H
Recycled aggregate M
JIS A 5022 class M
Fig. 2. Absolute dry density and water absorption of recycled aggregate.
Fig. 3. Water absorption of recycled aggregate.
Table 4
Materials used.
Item Type Density (g/cm3
)
Cement Ordinary Portland cement 3.16
Water Ground water (well water) 1
Admixture Expansive agent (ettringite type) 3.12
Superplasticizer High performance (standard type) 1.04
Normal(standard type) 1.07
K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385 381

4. environmental burden. The recycling rates by concrete type are
shown in Fig. 10. Introduction of recycled aggregate to the fine
and coarse aggregate enabled a recycle rate ranging from 39% to
76%. The BEE value, a ratio of Q (environmental performance)
per L (environmental burden) of the building calculated with
CASBEE (Comprehensive Assessment System for Built Environ-
ment Efficiency), was 8.3 as the largest record. This is due to the
considerable reduction of L value from 12 to 10 by the application
of the recycled aggregate.
Table 5
Mix proportions of concrete.
Namea
Aggregate type W/B (%) Unit mass (kg/m3
) Superplasticizer
Coarse Fine Water Cement Expansive agent Fine aggregate Coarse aggregate
HNP40 Recycled H Mixed sandb
40 170 425 – 869 890 Cx0.525–0.8%
HNP46 46 370 913
HNP52 52 327 946
HMP40 Recycled M 40 425 – 869
HMP46 46 370 913
HMP52 52 327 946
HMB46 46 350 20 913
HNB46 Mixed sandb
350 929
NNP46 Crashed rock 370 – 916 918
a
H: type of coarse aggregate, N–M: type of fine aggregate, and P–B: with/without expansive agent.
b
Mixed sand: [Pit sand: crashed sand = 30:70] percent by mass.
Table 6
Properties of fresh concrete.
Name Slump (cm) Air content (%) Temp. (°C) Chloride ion content (kg/m3
) Bleeding (cm3
/cm2
) Workability
HNP40 21.5 4.2 13 0.025 – Good
HNP46 19.5 5.7 11 0.022 0.13 Good
HNP52 20.5 4.8 12 0.021 – Good
HMP40 20.5 4.2 16 0.036 – Good
HMP46 20.5 5.4 15 0.037 0.12 Good
HMP52 20.0 5.2 16 0.031 0.16 Good
HMB46 20.5 5.8 17 0.035 0.11 Good
HNB46 21.5 4.9 17 0.023 0.12 Good
NNP46 20.5 5.8 10 0.021 0.13 Good
Notes JIS A 1101 JIS A 1128 JIS A 1156 JIS A 1144 JIS A 1123 Visual observation
Fig. 4. Compressive strength of concrete.
Fig. 5. Length changes in recycled aggregate concrete.
Photo 1. Mock-up specimens.
Fig. 6. Total strains at the center of the test wall.
382 K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385

5. 5. Observation of time-dependent performance of the recycled
aggregate concrete
5.1. Overview
Durability of the three-type recycled aggregate concrete walls,
HMB52, HNP52 and NNP52 (Photo 3), constructed at the south side
of the site has been continuously monitored. The results up to one
year are shown in this paper. The types of concrete and testing
items and methods are shown in Tables 9 and 10. A model speci-
mens subjected to core sampling is shown in Fig. 11.
Specimens for compressive strength testing were sealed and
placed close to the real structure while those for outdoor exposure
were demolded at the age of 5 days and placed together with the
sealed specimens. Cores were taken from the model specimen at
the age of 1 year and subjected to compressive strength test. The
corrosion of reinforcement was evaluated by means of the natural
potential method with copper sulfate electrode (CSE) using the real
structure. Measuring point was at every 30 cm from the top of the
wall and three measurements of upper, center and lower were per-
formed at each measuring point.
5.2. Results of the observation
(1) Compressive strength
Results of the compressive strength test are shown in Fig. 12.
Compressive strength of the normal aggregate concrete was
slightly larger than that of the recycled aggregate concretes while
the difference was not significant because of the larger targeted
strength by 3 N/mm2
of the normal aggregate concrete.
Strength of specimens subjected to various curing conditions
for a long time showed equal or larger strength than that with
the standard curing of 28 days.
Photo 2. Building construction of trial basis.
Table 7
Outline of building.
Building use Office
Total floor area 8914 m2
Building area 516 m2
Building height 18.1 m
Structure Reinforced concrete, 5 floors and 0 basement
Construction period 2009.11–2011.10
Table 8
Specification of recycled aggregate concrete.
Concrete type Aggregate Expansive agent Design strength Fc (N/mm) Applied part Amount (m3
)
Coarse Fine
HMB High quality recycled (H) Mid-quality recycled Yes (B) 30 (33)a
Floor (5th floor) 31.5
24 (27) Retaining wall 17.0
HHP High quality No (P) 30 (33) Wall and column (4th floor) 15.0
HNP Normal (N) No (P) 24 (27) Retaining wall (with base) 68.0
HNB Yes (P) 24 (27) Retaining wall (with base) 51.5
Total (m3
) 183.0
a
Nominal strength.
Fig. 7. Results of slump test.
Fig. 8. Compressive strength.
Fig. 9. Actual amount of pumping rate and hydraulic pressure loss.
K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385 383

6. (2) Carbonation depth
Relationship between concrete type, age and accelerated car-
bonation depth is shown in Fig. 13. The carbonation depths were
in an order of HMB52 HNP52 NNP52and the depths were equal
or less than those with equivalent water-cement ratio of W/
C = 0.50 [5].
(3) Appearance
The test wall surfaces were fair-faced but no particular changes
were observed at ages of 3 months and one year compared to the
appearance immediately after the completion (Photo 3). They are
in a sound condition and no failures are reported up to now.
(4) Corrosion of reinforcement
Natural potentials of steel reinforcement arranged in the test
wall are shown in Fig. 14. At ages of 3 months and one year after
completion, the natural potentials indicated the soundness of the
reinforcement with a confidence more than 90% probability free
from the corrosion.
Photo 3. Appearance of the recycled aggregate concrete construction.
16.2 7.4 36.7 39.7
16.4 7.5 37.1
16.7 7.6
Cement Water Fine aggregate Coarse aggregate
Unit:wt. ( )
7. 7 39.7
7. 37.1
.
Recycled coarse fine aggregateconcrete Re. rate 76
Recycled coarse aggregateconcrete Re. rate 39
Normal aggregate concrete Recycling rate 0
36.0 39.7
39.0
Note: W/C 45.5
Cement Water Fine aggregate Coarse aggregate
Cement Water Fine aggregate Coarse aggregate
Fig. 10. Recycling rates by concrete type.
Table 9
Types of concrete.
Name Coarse aggregate Fine aggregate Expansive agent W/B (%)
HMB52 High quality recycled (H) Mid-quality recycled (M) Yes (B) 52
HNP52 Normal (N) No(P)
NNP52 Normal (N)
Table 10
Test items and methods.
Test item Testing method Curing conditions (Material age) [Part]
Compressive strength JIS A 1108 Standard (4 weeks), sealed (13 weeks, 1 year), outdoor exposure (1 year), and core (1 year)
Accelerated carbonation depth JIS A 1153 20 °C, 60%R.H., CO2 5% (1, 4, 8, 13, 26 weeks)
Appearance Visual inspection Outdoor exposure (13 weeks, 1 year) [Retaining wall]
Corrosion of reinforcement Natural potential Outdoor exposure (13 weeks, 1 year) [Retaining wall]
60cm
46cm
20cm
4cm
ϕ10cm
Hanging jig
Fig. 11. Model specimen.
Fig. 12. Compressive strength between type, age and curing conditions.
384 K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385

7. 5.3. Summary
Durability of recycled aggregate concrete applied to the real
building construction was studied in terms of changes in compres-
sive strength, accelerated carbonation depth, appearance and rein-
forcement corrosion using natural potential. The test building was
found to be a sound condition and no signs of deterioration were
detected.
6. Conclusions
Reduction of the environmental burden is a major requirement
for the recent building constructions. This paper shows an example
of application of the recycled aggregate concrete to the new con-
struction of a research laboratory building of Kajima Technical Re-
search Institute. The recycled aggregate concrete introduced in this
paper is a promising technology to meet the above requirement
and further development is expected.
Acknowledgment
Authors thank Mr. Mikio Kanezuka at Sakura SOC Corporation
and other persons involved for their generous cooperation in deter-
mining the mix proportions of concrete.
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Fig. 13. Relationship between type, age and accelerated carbonation depth.
Fig. 14. Corrosion of reinforcement.
K. Yoda, A. Shintani / Construction and Building Materials 67 (2014) 379–385 385