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Durability of Acrylic Sealants Applied to Joints of Autoclaved Lightweight Concrete Walls: Evaluation of Exposure Testing

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In Japan acrylic sealants are traditionally the sealant products of choice when specified for use between autoclaved lightweight concrete (ALC) panels. Although, in general terms, the mechanisms of the deterioration of acrylic sealants are well known its long-term durability to outdoor exposure has not, however, been fully investigated. The research described in this paper focuses on the change in the properties and deterioration of acrylic sealant products when exposed to outdoor testing. The two stage project consisted of (i) on-site investigations of deteriorated acrylic sealants that had been placed in external joints of ALC-clad buildings; and (ii) outdoor exposure testing of different types of acrylic sealant in three climate regions located in Japan. The results of the work from the first stage of the study revealed the following. Two-sided adhesion joint configurations installed in deep panel ALC cladding were more reliable than three-sided adhesion joints used for thin panel ALC cladding from the viewpoint of the durability of the sealed joint installed in actual buildings. Most fractures of the sealed joint could be characterized as failure in peel (or thin layer cohesive failures), in which the sealant ruptured at the interface with the ALC substrate to which it was applied. Additionally, in 47 of 62 locations surveyed, surface cracks were apparent on the coating that had been applied to protect the sealant. The second stage of the project focused on the degree of deterioration of coated and non-coated acrylic sealants subjected to outdoor exposure testing in a cold, a warm, and a subtropical climate. Results from this stage showed that aging of the sealant, as determined by the degree of surface cracking, expectedly depended on the local temperature and the respective degree of exposure to solar radiation. It was determined that the longer the exposure period, the lower the tensile performance of the acrylic sealants. The elongation of three-sided adhesive joint configurations after 5 years exposure testing decreased remarkably and their maximum elongation was less than 50 %. A significant number of sealed joints after 5 years ofexposure had ALC substrate failure.
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Durability of acrylic sealants applied to joints of autoclaved lightweight
concrete (ALC) walls – Evaluation of exposure testing
Hiroyuki Miyauchi1*, Michael A. Lacasse2, Noriyoshi Enomoto3, Shigeki Murata 4,
and Kyoji Tanaka5
1* Assistant Professor, Dr. of Eng., Chungnam National University, Dept. of Architectural
Engineering, Daejeon, South Korea
2 Senior Research Officer, Ph.D., P. Eng., National Research Council Canada, Institute for
Research in Construction, Ottawa, Canada
3 Scientific committee member, Dr. of Eng., Japan Sealant Industry Association, Tokyo,
Japan
4 Scientific committee member, ALC Association, Tokyo, Japan
5 Emeritus Professor, Dr. of Eng., Tokyo Institute of Technology, Kanagawa, Japan
*Corresponding author: Assistant Professor, E-mail: miyauchi@cnu.ac.kr,
Phone: +82-42-821-7732, Fax: +82-42-823-9467
ABSTRACT: In Japan acrylic sealants are traditionally the sealant products of choice when
specified for use between autoclaved lightweight concrete (ALC) panels. Although in general
terms the mechanisms of deterioration of acrylic sealants are well known its long-term
durability to outdoor exposure has not, however, been fully investigated. The research
described in this paper focuses on the change in properties and deterioration of acrylic sealant
products when exposed to outdoor testing. The two stage project consisted of (i) on-site
investigations of deteriorated acrylic sealants that had been placed in external joints of
ALC-clad buildings; (ii) outdoor exposure testing of different types of acrylic sealant in three
climate regions located in Japan. The results of the work from the first stage of the study
revealed the following. Two-sided adhesion joint configurations installed in deep panel ALC
cladding were more reliable than that of three-sided adhesion joints used for thin panel ALC
cladding from the viewpoint of durability of the sealed joint installed in actual buildings.
Most fractures of the sealed joint could be characterized as thin layer cohesive failures in
which the sealant ruptured at the interface with the ALC substrate to which it was applied. As
well, in 47 of 62 locations surveyed, surface cracks were apparent on the coating that had
been applied to protect the sealant. The second stage of the project focused on the degree of
deterioration of coated and non-coated acrylic sealants subjected to outdoor exposure testing
in a cold, a warm, and a subtropical climate. Results from this stage showed that aging of the
sealant, as determined by the degree of surface cracking, expectedly depended on the local
temperature and the respective degree of exposure to solar radiation. It was determined that
the longer the exposure period, the lower the tensile performance of the acrylic sealants. The
elongation of three-sided adhesive joint configurations after 5 years exposure testing
decreased remarkably and its maximum elongation was less than 50%. A significant number
of sealed joints after 5 years-exposure had ALC substrate failure.
KEYWORDS: Sealant, autoclaved lightweight concrete, wall panel, durability, exposure
testing
Introduction
The "Housing Quality Assurance Act" [1] was established in 2000 in Japan and as a
consequence, a ten year warranty period was imposed on industries producing and installing
waterproofing systems. Sealed joints installed in buildings form part of a building façade’s
waterproofing system and thus require long-term performance and it is therefore necessary to
verify the durability of currently available sealed joint systems. In Japan when considering
performance standards and specifications for sealed joint systems, the performance of
sealants is regulated by two test methods: (i) "Sealants for Sealing and Glazing in Buildings"
(JIS A 5758)[2], and; (ii) "Testing Methods of Sealants for Sealing and Glazing in
Buildings"(JIS A 1439)[3].
The primary specification and guideline documents that respectively provide for the
material, design, and construction of sealed joints include: "Public Construction Standard
Specifications" [4] and "The Construction Work Supervision Guideline" [5]; both these
documents are regulated by the Ministry of Land, Infrastructure, Transport and Tourism of
Japan. The Architectural Institute of Japan (AIJ) also provides the "Recommendation for
Design of Joints and Jointing for Control of Water and Air Penetration in External Walls" [6].
The performance regulations for the design and installation of sealed joints in building and
constructed works have been established to improve the long-term performance of such
products used in both in government assets and those of the private sector.
Sealed joint systems for ALC (Autoclaved Lightweight aerated Concrete) panels have
long followed construction practices as provided for external walls of industrial buildings.
Acrylic sealant products have for a considerable time been used in Japan for ALC panel
joints, and perhaps elsewhere around the globe, because: (i) coatings can readily be applied to
these products (thus prolonging their aesthetic performance); (ii) their initial tensile strength
is low thus offering a reduced risk to premature tensile failure of the ALC panel substrate,
and; (iii) this sealant can be nonetheless be installed in conditions where the substrate may be
moist or indeed wet. However, a systematic verification concerning the long term
performance of acrylic sealants used in ALC panel structures and which may have been
exposed to up to 30 years aging has not yet been done. Consequently a study was undertaken
to investigate the condition of deteriorated sealed joints of buildings clad with ALC panels
such that some basic information on the actual condition and degree of deterioration of aged
sealed joints could be obtained. Following the information gained from this study a
subsequent work was initiated that focused on the exposure testing of acrylic sealed joints
that were tested to evaluate their mode of degradation and the likelihood of achieving
long-term performance.
Degradation of sealed joints installed on panels of an ALC-clad building
Outline of investigation
An outline of the investigation of sealed joints installed on panels of an ALC-clad
building is shown in Table 1. The ALC panels on the building consists of two basic types that
may be classified according to the depth of the panel, specifically (i) The deep ALC panel,
for which the depth of the ALC panel cladding is 100 mm, and; (ii) the thin ALC panel
where the ALC panel depth may be 35, 37, or 50 mm deep. The deep ALC cladding panels
are typically used for homes, commercial buildings or factories having steel frame
construction whereas the thin ALC panels are normally used for homes or on low-rise
buildings having wood frame construction. In this study, the buildings for which the
investigations were completed, all of which were constructed over ten years ago, were
inspected in respect to the type of sealants used in the joints, the degree of degradation of the
sealants; their respective strength characteristics were subsequently determined from
laboratory testing. The joint types that had been used for the deep ALC panels or the thin
ALC panels are shown in Table 2. As may be seen in Table 2, the deep ALC cladding panels
used two-sided working joints whereas the thin ALC panels used three-sided non-working
joints. Given that the short side of the joint length along the deep ALC panel deforms to a
greater extent than that of a joint on the long side of the panel, is was determined that the
representative panel joint would be a two-sided adhesion joint having a width of 10 mm. On
the other hand, the joint for the thin ACL panel was considered a three-sided adhesion joint
of 7 mm width.
Results of investigation
Results of deteriorated sealed joints - The sealant product condition is provided in
terms of a qualitative assessment of the extent of damage and classification of sealed joints
between ALC panels are shown in Table 3. In buildings aged over 20 years, all sealed joint
products were one component acrylic sealants. Whereas for buildings less than 20 years of
age only two component urethane sealants had been used for the sealed joints. Because the
amount of anticipated movement in the sealed joint between the deep ALC panels was large,
the degree of usage of two component urethane sealant was high given its capacity to
accommodate movement.
There was no evidence of any complete damage to the sealed joint (symbol X),
regardless of the depth of the panel, however partial failure (symbol Δ) of the sealed joint
was observed (4/62 damage) in four locations in thin panels, specifically: the ALC panel
having 50 mm depth had partial damage (symbol Δ) evident for one acrylic (1/20 damage)
and one urethane sealant (1/3 damage), and the ALC panels with 35 (37) mm wall depth had
partial damage for two acrylic joints (2/25 damage).
Crack conditions of sealed joint - Examples of damaged sealant products applied to
movement joints of deep ALC panels (two-sided adhesion) and the non-movement
(three-sided adhesion) joints of thin panels are shown in Fig. 1. All damaged sealed joints
(symbol ) were those occurring in thin ALC panels and for joints having three-sided
adhesion, 2 of these were evident for 50 mm deep panels and another 2 for 35 mm deep
panels. In both instances cohesive failure occurred at the center of the sealed joint and where
cracks were observed. In 47 of the 62 sealed joints inspected cracks were evident on the
surface coating material (i.e. damage evident to 47/62); these cracks did not depend on
movement of the structure or the type of sealant to which they were applied. The coating
material has in fact a reduced performance in accommodating deformation as compared to
that of sealants. It was also evident that the sealed joints along the short side of the panel have
significantly more cracks than joints along the longer side of the panel. It is thought that the
degree of expansion and contraction of the joint on the short side of the panel is greater than
that of the longer side of the panel.
Test results of basic properties - The hardness [7] and tensile strength [3] of 17 year old
sealant product used in joints of a wood frame constructed home were measured by testing
machine. The hardness of the sealed joint was measured with a Shore type A hardness meter
(JIS K 6253). The value for hardness of sealant was approximately 60A on both sides of the
sealed joint. An unaged sealant of the same product type was estimated to be 20A when first
installed (Table 6). The change in hardness of the aged produced appears to confirm therefore
the degradation of the sealants over time.
The tensile test for the sealed joint was carried out using a special jig shown in Fig. 2.
Fourteen tensile test specimens were evaluated; the maximum tensile stress ranged between
0.36 and 0.73 N/mm2 with the mean value being 0.54 N/mm2. The elongation at maximum
load ranged between 7 and 21% and provided a mean value of 15%. Most sealed joint
fractures were characterized as thin layer cohesive failures in which the sealant fractured at
the interface between the sealant and the ALC substrate. The maximum elongation at fracture
of the sealed joint extended from 53 to 223% with a mean value of 117%.
Outdoor exposure tests
Outline of outdoor exposure test
As described in Table 4, the outdoor exposure tests were carried out at three different
locations in Japan over a 5 year period; each location had a different climate. Control
specimens were also prepared to which the sealants exposed to the different climates were
compared; these were kept in indoor laboratory conditions, as prescribed in Table 4. The
evaluation parameters included the: (i) effect of climate conditions (e.g. ultraviolet radiation,
temperature, and moisture load), and; (ii) effect of joint type between ALC panels, and: (ii)
effect of sealant and coating material types.
Test specimens and test methods
Test specimens - The specimens are shown in Fig. 3 and the items inspected over the
course of the outdoor exposure test are shown in Table 4. The joint types include: a two-sided
adhesion joint (joint width: 10 mm, joint depth: 8 mm) and three-sided adhesion joint (joint
width and depth: 7 mm). Low density one component acrylic sealant commercially available
Japanese products were those subjected to tests. The effect of coating materials was evaluated
and the test specimens were prepared both with and without a coating material applied to the
exterior surface of the joint. All sides of ALC substrate, with the exception of that surface on
which sealant was applied, were coated with one component silicone sealant in order to
protect the substrate from water absorption when exposed to the outdoors. The test specimens
were cured indoors at 23±2 °C for 4 weeks before starting the outdoor exposure test. The
number of test specimens for each of test parameters was three.
Exposure test method - As shown in Fig .4 the geographical locations of the exposure
testing sites for Rikubetsu, Yokohama, and Miyako Island are evidently quite different and
consequently the local climate conditions vary greatly from one location to another. The test
specimens placed in the outdoor exposure site at these three locations were set up on testing
tables inclined at 45 degrees (Fig. 4). On the other hand, test specimens prepared as control
specimens were cured in a darkroom with no sunlight and maintained at a temperature of
23±2 over the test period.
Fig. 5 shows the outdoor temperature conditions at the three outdoor exposure sites
over a selected exposure period in October. The mean value for the maximum outdoor
temperature over a five year period for the warmest exposure site (Miyakojima Island) was
29.4 . Whereas the mean value over five years for the minimum outdoor temperature and
for this same exposure site was 18.2 . On the other hand, Rikubetsu is an exposure site
where temperature differences are large and the mean value for maximum temperature over
five years was 18.6 and corresponding minimum temperature was -9.6 . Therefore, the
exposure sites where thermal degradation is most severe, in order of decreasing severity are:
Miyakojima Island > Yokohama > Rikubetsu.
Evaluation method for degradation of sealed joints - The degree of degradation of the
sealed joint is evaluated by observation of the surface of the sealed joint, with use of the
hardness meter (Shore Type A), and as well, tensile tests. Moreover, the tensile tests were
carried out by fixing the test specimen to a special jig (Fig. 2). The tensile rate of deformation
was 5 mm/min. and the test temperature was 23±2 .
Results of outdoor exposure tests
Surface condition of sealed joints – Fig. 6 shows the surface condition of the sealed
joints after 5 years of outdoor exposure at the different exposure site locations. In Table 5 are
presented results of the aging (staining) and degree of cracking from the outdoor exposure
tests. As might be expected, the degree of aging (staining) of test specimens after 5 years
exposure is greater than that at the initial exposure period (0y) and after 2 years exposure, in
particular, the degree of staining and dirt pick up of test specimens exposed to the Yokohama
climate is the greatest. It is thought that dust is more prevalent on the surface of sealants at
the Yokohama exposure site because this site is close to a highway. However, is was not
possible to confirm the differences in the degree of staining and dirt pick up by the presence
or not, of coating applied to the exterior surface of three-sided joint specimens. As for the rate
of occurrence of cracks on sealed joints, it was evident that test specimens exposed at the
Miyako Island and the Yokohama sites were high. The rate of occurrence of cracks of coated
sealant products for three-sided adhesion joints was greater than that of products in joints
having two-sided adhesion.
Hardness measurement results of sealed joints - The hardness of sealed joints exposed
to the different exterior climate conditions is shown in Table 6. The results indicate that the
longer the exposure period to which the specimens were subjected, the greater the value of
hardness of the sealed joint product. As for the importance of exposure site to age and harden
sealant products, the results indicate the following order, in decreasing order of hardness
value: Miyakojima (52 in hardness) > Yokohama (49 in hardness) > Rikubetsu (39 in
hardness). The results also indicated that the hardness of sealed joints without a coating was
greater than that of joint products with a coating.
Tensile test results – Fig. 7 shows the maximum tensile stress obtained for sealant
specimens that had been coated with paint for outdoor exposure testing. The results revealed
that the longer the exposure period, the greater the tensile stress achieved in the sealant
specimens. The location of the exposure site affected the severity of the exposure conditions
and consequently the degree of aging and resulting tensile stress of aged products. It was
determined on the basis of results from tensile tests that the order of exposure severity staring
with the most severe exposure location and proceeding toward less severe exposure locations
was: Myakojima > Yokohama > Rikubetsu. The tensile stress achieved for three-sided
adhesion joint specimens was greater than that of two-sided adhesion joints. Fig. 8 shows the
maximum elongation achieved of sealed joints in tension; results indicate that the longer the
exposure period, the lower the degree of elongation of the sealed joint specimen.
If considering the importance of joint type, the degree of elongation of three-sided
adhesion joint specimens was remarkably reduced as compared to two-sided joint specimens
and as well, the maximum elongation was less than 50%. The results did not confirm that
differences existed amongst the various three-sided adhesion joint specimens and neither
were these affected by the severity of conditions at the different exposure sites. However, the
lower degree of elongation obtained for two-sided adhesion joint specimens varied in relation
to the severity of the climate for which the least degree of elongation was obtained for the
exposure location having the more severe exposure conditions; specifically, in order of more
to least severe effects this was: Miyakojima < Yokohama < Rikubetsu.
Fig. 9 and Table 7 provide information on the type of failure of the sealed joint
specimens in tensile tests; these could be classified into four types of failure: (i) cohesion
failure (symbol: ); (ii) mixed mode adhesive failure of the sealant and ALC substrate
(symbol: Δ); (iii) failure in peel (symbol: -), and; failure of the ALC substrate (symbol: ×).
The sealed joint specimens, used as control specimens and cured indoors in laboratory
conditions, all failed in cohesion (symbol: ). On the other hand, the results confirmed that
the sealed joint specimens after 2 years of exposure testing had mixed mode adhesion failure
with sealant and ALC substrate failure (symbol: Δ) as well as failure in peel (symbol: -). It
was also revealed that a considerable number of the sealed joint specimens after 5 years
exposure testing had failed at the ALC substrate (symbol: ×). The value of the 50% modulus
of the sealed joint specimens having three-sided adhesion joints could not be measured
because their modulus was less than 50 %.
Conclusions
The conclusions from this study are as follows.
(1) Two-sided adhesion joints used for sealing deep ALC panels were more reliable than that
of three-sided adhesion joints used for thin ALC panels type from viewpoint of durability
and degradation of the sealed joint of ALC panels in actual buildings. The damage to
three-sided adhesion joints used in thin ALC panels was confirmed from partial damage
located at 4 locations of 62. The hardness of acrylic sealant was approximately 60A for
sealants used in joints of 17 year old building. As a result of the tension tests, the
maximum tensile stress was 0.36-0.73 N/mm2 (Mean value 0.54 N/mm2). The maximum
elongation at fracture of sealed joint was 53-223 % (Mean value 117%). Most fractures of
sealed joint were thin layer cohesion failure where the sealant was fractured at interface
with the ALC substrate. In 47 or 62 sealed cracks on the surface coating was observed,
however, these cracks did not develop as a result of the degree of movement of joints in
the structure or the inappropriate choice of sealant product.
(2) As results of the surface condition of sealed joint after 5 years outdoor exposure, the
aging (degree of staining) and the extent of occurrence of cracks depended on the
environmental conditions apparent at any exposure location. In particular, the exposure
site with the highest average monthly temperature (climate zone) had in this study the
greatest effect on the durability of the sealed joint. The longer the exposure period of the
sealed joint, the lower the durability of sealed joint in respect to values obtained the tensile
stress and elongation. The degree of elongation of three-sided adhesion joints after 5 years
exposure was markedly decreased and its maximum elongation was less than 50%. A
number of sealed joints after 5 years exposure testing had failure at the ALC substrate
(symbol: ×).
Therefore, given that the maximum elongation acrylic sealant is less than 50% and that
the degree of movement accommodation of three-sided adhesion joints in ALC panels with
such types of sealant is reduced, thereby increasing the likelihood of premature joint failure,
it was determined that a suitable sealant for use on ALC substrates is a sealant having a
greater degree of movement accommodation that acrylic sealants and as well a product that
has enhanced durability; as well, the product should be applied in the normal fashion as a
two-sided joint.
Acknowledgements
This work was performed as part of the research activities of the working group for the
“Research of Sealants for Sealed ALC panel Joints“ conducted by the Tokyo Institute of
Technology, Autoclave Lightweight aerated Concrete panels and the Japan Sealant Industry
Association. This work was also supported by the Basic Science Research Program of the
National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science
and Technology, Korea (2010-0011927). Some researchers were funded by the Korean
Government and supported by the 2nd Korea Brain (BK21) foundation. The authors are
grateful to all these parties for their support.
References
[1] The Building Center of Japan: The Housing Quality Assurance Act and Japan Housing
Performance Indication Standards 2004, p. 135, 2005
[2] JIS A 5758-2010, Sealants for sealing and glazing in buildings, Japanese Standards
Association, Japanese Industrial Standards Committee, 2010
[3] JIS A 1439-2010, Testing Methods of Sealants for Sealing and Glazing in Buildings,
Japanese Industrial Standards Committee, p. 46, 2010
[4] Ministry of Land, Infrastructure, Public Construction Standard Specifications, p. 447,
2010
[5] Ministry of Land, Infrastructure, Transport and Tourism, The construction work
supervision guideline, p. 1780, 2010
[6] Architectural Institute of Japan, Recommendation for Design of Joints and Jointing for
Control of Water and Air Penetration in External Walls, p. 357, 2008
[7] JIS K 6253-2006, Rubber, vulcanized or thermoplastic - Determination of hardness,
Japanese Standards Association, Japanese Industrial Standards Committee, 2006
List of tables
Location Hokkaido, Tokyo, K obe, Kagawa
Pane l t ype
Building age: 10-years
Deep panel type: ALC panel with
100 mm-wall depth
- Structure: steel frame construction,
- Panel Fixing method: Ro cking panel fixing system
- Sealed joint: Two-sided adhesion j oint
Thin panel
type
ALC panel with
50 mm-wall depth
- Structure: steel or wood frame co nstruction,
- Panel Fixing method: s crew fastening s ystem
- Sealed joint: Three-sided adhesion joint
ALC panel with
35(37)mm wall
depth
- Structure: wo od frame construction,
- Panel Fixing me thod: Fastening syst em by screws
- Sealed joint: Three-sided adhesion joint
Researc h
me th od Sampling of sealants from actual external wall in 4 regions
Evaluation
parameters
- Visua l inspection on the surface of sealants with coating material
(Dete rioration, crack cond ition)
- Hardness of sealants, tensile stress of sealants
Location Hokkaido, Tokyo, K obe, Kagawa
Pane l t ype
Building age: 10-years
Deep panel type: ALC panel with
100 mm-wall depth
- Structure: steel frame construction,
- Panel Fixing method: Ro cking panel fixing system
- Sealed joint: Two-sided adhesion j oint
Thin panel
type
ALC panel with
50 mm-wall depth
- Structure: steel or wood frame co nstruction,
- Panel Fixing method: s crew fastening s ystem
- Sealed joint: Three-sided adhesion joint
ALC panel with
35(37)mm wall
depth
- Structure: wo od frame construction,
- Panel Fixing me thod: Fastening syst em by screws
- Sealed joint: Three-sided adhesion joint
Researc h
me th od Sampling of sealants from actual external wall in 4 regions
Evaluation
parameters
- Visua l inspection on the surface of sealants with coating material
(Dete rioration, crack cond ition)
- Hardness of sealants, tensile stress of sealants
Table 1 Outline of investigation concerning ALC building
Two-sided adhesion joint Three-sided adhesion joint
Long side joint Short side joint Long side joint Short side joint
Two-sided adhesion joint Three-sided adhesion joint
Long side joint Short side joint Long side joint Short side joint
7
7
Sealant
Backup material
W8×D8mm W10×D10mm W 7×D7mm W7×D7mm
Table 2 Sealed joint types
ALC panel
Table 3 Sealant inspection results
Elapsed year Sealant
type*1
Depth of ALC wall panel
Total
100 mm 50 mm 35(37) mm
Two-sided adhesion joint Three-sided adhesion joint
*2 *2 ×*2 *2 *2 ×*2 *2 *2 ×*2
5-9 AC-11 0 0 2002005
PU-2500 5
10-14 AC-1 91062018
PU-2200100 3
15-19 AC-1 3 0 0 3 0 0100 016
PU-2300110 5
20-21 AC-1 50050010
PU-2 0
Total 14 0 0 212 0232 062
Elapsed year Sealant
type*1
Depth of ALC wall panel
Total
100 mm 50 mm 35(37) mm
Two-sided adhesion joint Three-sided adhesion joint
*2 *2 ×*2 *2 *2 ×*2 *2 *2 ×*2
5-9 AC-11 0 0 2002005
PU-2500 5
10-14 AC-1 91062018
PU-2200100 3
15-19 AC-1 3 0 0 3 0 0100 016
PU-2300110 5
20-21 AC-1 50050010
PU-2 0
Total 14 0 0 212 0232 062
*1 AC-1:1 component acrylic sealant , PU-2: 2 component urethane sealant
*2 : No d a mage on sea led jo i nt
: Slight (partial) damage on sealed joint
×: Damage on se aled joint in many places
Item Conditions
Test
specime n
Sealant Acrylic sealants (Type A, Type B, Type C)
Coating material With coating, Without coating
Joint type Two-sided adhesion joint, Three-sided adhesion joint
Curing time 4 weeks indoor environment room at 20±3
Exposure
test
Exposure
location
Rikubetsu Climate: Cold climate area
Place: Rikubetsu exposure testing site (October 17, 2001-)
Yokohama Climate: Warm climate area,
Place: Roof at Tokyo Institute of Technology (Nov. 6, 2001-)
Miyako
Island
Climate: Subtropical climate area
Place: Japan Weathering test center (Nov. 6, 2001-)
Indoor
room
Climate: No degradation,
Place: Room (Temp. 23±2℃)
(October 17, 2001-)
Evaluated
exposure periods No de terioration (Initial), 2 ye ars, 5 years
Item Conditions
Test
specime n
Sealant Acrylic sealants (Type A, Type B, Type C)
Coating material With coating, Without coating
Joint type Two-sided adhesion joint, Three-sided adhesion joint
Curing time 4 weeks indoor environment room at 20±3
Exposure
test
Exposure
location
Rikubetsu Climate: Cold climate area
Place: Rikubetsu exposure testing site (October 17, 2001-)
Yokohama Climate: Warm climate area,
Place: Roof at Tokyo Institute of Technology (Nov. 6, 2001-)
Miyako
Island
Climate: Subtropical climate area
Place: Japan Weathering test center (Nov. 6, 2001-)
Indoor
room
Climate: No degradation,
Place: Room (Temp. 23±2℃)
(October 17, 2001-)
Evaluated
exposure periods No de terioration (Initial), 2 ye ars, 5 years
Table 4 Test parameters
Table 5 Aging (staining) and crack condition from outdoor exposure testing
0
12345
None Severe
Aging (stain) degree
0
12345
None Severe
Aging (stain) degree
Se al an ts C oating Joint
type
Aging (Stain) Cracks
Rikubetu Yokohama Miyako Rikubetu Yokohama Miyako
0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y
Type A
Without 2 0 1
3 0 1 3 0 0 1 0 0 1 0 1 2 0 1 1
3 0 1 2 0 1 2 0 0 1 0 0 1 0 1 2 0 1 1
With 2 0 0 1 0 2 3 0 0 1 0 0 1 0 0 1 0 0 1
3 0 0 1 0 2 3 0 0 0 0 2 2 0 2 2 0 2 2
Type B
Without 2 0 1 2 0 3 3 0 1 1 0 0 0 0 0 0 0 0 0
3 0 1
3 0 3 3 0 1 1 0 0 0 0 0 0 0 0 0
With 2 0 0 2 0 2 4 0 1 1 0 0 0 0 1 0 0 1 1
3 0 0 2 0 2 3 0 1 1 0 2 2 0 1 1 0 2 2
Type C
Without 2 0 1 1 0 3 3 0 0 0 0 0 0 0 0 0 0 0 0
3 0 1 2 0 3 3 0 0 1 0 0 0 0 0 0 0 0 0
With 2 0 1
3 0 3 4 0 1 1 0 0 1 0 0 1 0 2 2
3 0 1 1 0 3 4 0 1 1 0 0 2 0 2 2 0 2 2
Se al an ts C oating Joint
type
Aging (Stain) Cracks
Rikubetu Yokohama Miyako Rikubetu Yokohama Miyako
0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y 0y 2y 5y
Type A
Without 2 0 1
3 0 1 3 0 0 1 0 0 1 0 1 2 0 1 1
3 0 1 2 0 1 2 0 0 1 0 0 1 0 1 2 0 1 1
With 2 0 0 1 0 2 3 0 0 1 0 0 1 0 0 1 0 0 1
3 0 0 1 0 2 3 0 0 0 0 2 2 0 2 2 0 2 2
Type B
Without 2 0 1 2 0 3 3 0 1 1 0 0 0 0 0 0 0 0 0
3 0 1
3 0 3 3 0 1 1 0 0 0 0 0 0 0 0 0
With 2 0 0 2 0 2 4 0 1 1 0 0 0 0 1 0 0 1 1
3 0 0 2 0 2 3 0 1 1 0 2 2 0 1 1 0 2 2
Type C
Without 2 0 1 1 0 3 3 0 0 0 0 0 0 0 0 0 0 0 0
3 0 1 2 0 3 3 0 0 1 0 0 0 0 0 0 0 0 0
With 2 0 1
3 0 3 4 0 1 1 0 0 1 0 0 1 0 2 2
3 0 1 1 0 3 4 0 1 1 0 0 2 0 2 2 0 2 2
Crack condition
0: No crack, 1: Slight cracking
2: Large crack, 3: Though crack
Table 6 Hardne ss of se alant for outdoor exposure testing
Sealants Coating Joint
type
Hardness
Rikubetu Yokohama Miyako Island
0y 2y 5y 0y 2y 5y 0y 2y 5y
Type A
Without 2
20
27 38
20
33 53
20
35 54
3 30 38 34 56 42 55
With 2 25 33 30 51 33 45
3 28 41 32 51 32 53
Type B
Without 2
11
22 45
11
35 63
11
33 59
3 29 45 33 47 39 60
With 2 25 34 33 46 32 40
3 30 38 36 47 35 49
Type C
Without 2
8
25 42
8
27 51
8
31 52
3 28 53 34 51 35 68
With 2 22 24 24 33 27 42
3 23 34 29 40 30 44
Average 13 26 39 13 32 49 13 34 52
Sealants Coating Joint
type
Hardness
Rikubetu Yokohama Miyako Island
0y 2y 5y 0y 2y 5y 0y 2y 5y
Type A
Without 2
20
27 38
20
33 53
20
35 54
3 30 38 34 56 42 55
With 2 25 33 30 51 33 45
3 28 41 32 51 32 53
Type B
Without 2
11
22 45
11
35 63
11
33 59
3 29 45 33 47 39 60
With 2 25 34 33 46 32 40
3 30 38 36 47 35 49
Type C
Without 2
8
25 42
8
27 51
8
31 52
3 28 53 34 51 35 68
With 2 22 24 24 33 27 42
3 23 34 29 40 30 44
Average 13 26 39 13 32 49 13 34 52
A list of figure captions
Fig.1 Crack condition of sealed joints
Fig.2 Tensile test and sample specimen
Fig.3 Test specimen
Fig.4 Location of outdoor exposure test
Fig.5 Temperature conditions at the three exposure site locations
Fig.6 Outdoor exposure test results after 5 years
Fig. 7 Maximum tensile stress of sealants with painting material in outdoor exposure test
Fig. 8 Maximum elongation of sealed joints with painting material in outdoor exposure test
Fig. 9 Type of Fracture of sealed joint
ResearchGate has not been able to resolve any citations for this publication.
Infrastructure, Transport and Tourism, The construction work supervision guideline
  • Ministry
  • Land
Ministry of Land, Infrastructure, Transport and Tourism, The construction work supervision guideline, p. 1780, 2010
Recommendation for Design of Joints and Jointing for Control of Water and Air Penetration in External Walls
  • Architectural Institute
  • Japan
Architectural Institute of Japan, Recommendation for Design of Joints and Jointing for Control of Water and Air Penetration in External Walls, p. 357, 2008
Public Construction Standard Specifications
  • Ministry
  • Land
Ministry of Land, Infrastructure, Public Construction Standard Specifications, p. 447, 2010
Rubber, vulcanized or thermoplastic -Determination of hardness
JIS K 6253-2006, Rubber, vulcanized or thermoplastic -Determination of hardness, Japanese Standards Association, Japanese Industrial Standards Committee, 2006