U.S. patent application number 15/323917 was filed with the patent office on 2017-05-18 for method for slope improvement.
This patent application is currently assigned to DYFLEX CORPORATION. The applicant listed for this patent is DYFLEX CORPORATION. Invention is credited to Katsuhiro HIGASHI, Kazuyuki HORIE, Takeyasu MASUDA.
Application Number | 20170138012 15/323917 |
Document ID | / |
Family ID | 55019491 |
Filed Date | 2017-05-18 |
United States Patent
Application |
20170138012 |
Kind Code |
A1 |
HORIE; Kazuyuki ; et
al. |
May 18, 2017 |
METHOD FOR SLOPE IMPROVEMENT
Abstract
A method for slope improvement including layering a
life-extending layer on the surface of a protective layer made from
mortar or concrete sprayed onto a slope in order to prevent rain
water or the like from entering cracks in the protective layer,
inhibit degradation of the protective layer, and prevent mortar
pieces or concrete pieces from spalling off the protective layer,
the method for slope improvement being characterized in that the
life-extending layer is formed by a coating layer that has a crack
conformability of 0.8 mm or larger and has salt-blocking properties
and neutralization-preventing properties.
Inventors: |
HORIE; Kazuyuki; (Tokyo,
JP) ; HIGASHI; Katsuhiro; (Tokyo, JP) ;
MASUDA; Takeyasu; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DYFLEX CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
DYFLEX CORPORATION
Tokyo
JP
|
Family ID: |
55019491 |
Appl. No.: |
15/323917 |
Filed: |
July 6, 2015 |
PCT Filed: |
July 6, 2015 |
PCT NO: |
PCT/JP2015/069432 |
371 Date: |
January 4, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E02D 2600/40 20130101;
E02D 2300/0021 20130101; E02D 2300/007 20130101; E02D 2300/002
20130101; E02D 17/20 20130101 |
International
Class: |
E02D 17/20 20060101
E02D017/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 4, 2014 |
JP |
2014-138999 |
Claims
1. A method for slope face improvement, in which a
lifespan-extending layer is layered on a surface of a protective
layer comprising mortar or concrete sprayed on a slope face,
whereby penetration of rainwater from cracks that form in the
protective layer is prevented, degradation of the protective layer
is restricted, and detachment of mortar pieces or concrete pieces
from the protective layer is prevented, wherein a coating layer
having crack-following properties of 0.8 mm or greater,
salt-blocking properties and neutralization-preventing properties
is formed as the lifespan-extending layer.
2. The method for slope face improvement as claimed in claim 1,
wherein the coating layer comprises a polymer compound.
3. The method for slope face improvement as claimed in claim 1,
wherein a primer layer is formed between the protective layer and
the lifespan-extending layer.
4. The method for slope face improvement as claimed in claim 1,
wherein a topcoat layer is formed on the lifespan-extending
layer.
5. The method for slope face improvement as claimed in claim 2,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
6. The method for slope face improvement as claimed in claim 2,
wherein a primer layer is formed between the protective layer and
the lifespan-extending layer.
7. The method for slope face improvement as claimed in claim 2,
wherein a topcoat layer is formed on the lifespan-extending
layer.
8. The method for slope face improvement as claimed in claim 3,
wherein a topcoat layer is formed on the lifespan-extending
layer.
9. The method for slope face improvement as claimed in claim 6,
wherein a topcoat layer is formed on the lifespan-extending
layer.
10. The method for slope face improvement as claimed in claim 3,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
11. The method for slope face improvement as claimed in claim 6,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
12. The method for slope face improvement as claimed in claim 4,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
13. The method for slope face improvement as claimed in claim 7,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
14. The method for slope face improvement as claimed in claim 8,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
15. The method for slope face improvement as claimed in claim 9,
wherein the polymer compound is at least one selected from the
group consisting of: polyurethane resin, polyurea resin, epoxy
resin and acrylic resin.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for slope face
improvement, which prevents penetration of rainwater and the like
from cracks that form in a protective layer comprising mortar or
concrete sprayed onto a slope face, restricts degradation such as
salt damage or neutralization of the protective layer, and also
prevents detachment of the protective layer.
[0002] This application claims priority on the basis of Japanese
Patent Application 2014-138999 filed in Japan on Jul. 4, 2014 the
content of which is cited herein.
PRIOR ART
[0003] Mortar or concrete (also referred to below as "mortar etc.")
is sprayed onto cliff faces and slope faces which have degraded due
to weathering and the like, in order to protect the cliff face or
the slope face and to prevent instability of the faces, and a
protective layer comprising mortar or concrete is provided on said
faces (e.g., see Patent Document 1). Forms of cliff face or slope
face instability which may be cited include slides caused by
erosion, surface-layer crumbling, and collapse. A protective layer
comprising mortar etc. is provided in order to prevent this kind of
instability from occurring. The construction method involving
providing this kind of protective layer is one of the methods most
often used because not only does it provide a strong blocking
effect with respect to weather, temperature changes and seepage
water, it also has excellent properties in terms of
construction
PRIOR ART DOCUMENT
Patent Document
[0004] Patent Document 1: JP 2013-1585 A
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0005] In this regard, Japan has a large number of cliff faces and
slope faces, and in recent years there have not only been collapses
of slope faces and oblique faces as a result of frequent intensive
rainfall and natural disasters, there has also been loss of human
life. The collapse of slope faces etc. impedes rescuing people and
disaster relief. One cause of the collapse of slope faces etc. that
may be cited is due to the fact that rainwater etc. penetrates into
cracks formed as a result of degradation over time of the
protective layer comprising mortar etc. sprayed onto said slope
faces etc., and the rainwater erodes the rear surface of the
protective layer. As a result, cavities are formed between the
foundation and the protective layer, and this may lead to crumbling
of the protective layer.
[0006] Examples of the causes of degradation of the protective
layer comprising mortar etc. which may be cited include: (1)
penetration of rainwater from cracks produced by degradation over
time; (2) frost damage; and (3) chemical erosion (salt damage
(calcium chloride) and neutralization (carbon dioxide) etc.).
[0007] When the protective layer degrades, adhesion between the
protective layer and the foundation (slope face) is lost over time
to produce a floating state, and this causes a phenomenon in which
cracks are further enlarged as the foundation becomes looser.
Furthermore, degradation of the protective layer over time is also
caused by a phenomenon in which vegetation enters surface-layer
areas of the protective layer where sedimentation has occurred, and
this pushes the cracks wider apart.
[0008] Frost damage to the protective layer is a phenomenon in
which free water in the protective layer comprising mortar etc. and
moisture in the aggregate which has high water absorption are
repeatedly subjected to a freezing and thawing action, whereby
cracks are formed in the protective layer, the surface layer
portion of the protective layer peels, and breakage occurs from the
area close to the surface, causing gradual degradation.
[0009] Salt damage in the protective layer constitutes the
following phenomenon. During the winter period, snow-melting agents
such as calcium chloride are scattered on road surfaces in
mountainous regions in order to prevent freezing of roads due to
snow. When a motor vehicle or the like travels on a road surface on
which a snow-melting agent has been scattered and when the wind
blows, the snow-melting agent is dispersed and may adhere to the
protective layer formed on a cliff face or a slope face. When the
snow-melting agent adheres to the protective layer, steel material
in the protective layer corrodes and cracks form from inside the
protective layer due to volume expansion, so the mortar etc.
becomes detached. The mortar etc. is likely to degrade in this way
because of the snow-melting agents, and therefore the protective
layer has a short lifespan in mountainous regions and the mortar
etc. has to be frequently sprayed, which increases the cost
entailed in stabilizing cliff faces and slope faces.
[0010] Neutralization of the protective layer is a phenomenon in
which carbon dioxide (CO.sub.2) in the atmosphere penetrates into
the mortar etc., causing a carbonation reaction which reduces the
pH of the mortar etc. which is essentially alkaline. When
neutralization progresses from the surface of the protective layer
and reaches the steel material present within the protective layer,
this damages the passivation film. As a result, the steel material
corrodes and cracks are formed in the protective layer due to
volume expansion of the corroded material formed, and the
protective layer becomes detached.
[0011] The present invention has been devised in light of the
situation described above, and the aim thereof lies in providing a
method for slope face improvement which prevents penetration of
rainwater and the like from cracks that form in a protective layer
comprising mortar or concrete sprayed onto a slope face, restricts
degradation such as salt damage or neutralization of the protective
layer, and also prevents detachment of the protective layer caused
by the degradation.
Means for Solving the Problem
[0012] A method for slope face improvement according to one mode of
the present invention (referred to below as "the method for slope
face improvement according to the invention of this application")
is a method in which a lifespan-extending layer is layered on a
surface of a protective layer comprising mortar or concrete sprayed
on a slope face, whereby penetration of rainwater etc. from cracks
that form in the protective layer is prevented, degradation of the
protective layer is restricted, and detachment of mortar pieces or
concrete pieces from the protective layer is prevented, said method
being characterized in that a coating layer having crack-following
properties of 0.8 mm or greater, salt-blocking properties and
neutralization-preventing properties is formed as the
lifespan-extending layer.
[0013] According to the method for slope face improvement of the
present invention, the coating layer preferably comprises a polymer
compound.
[0014] According to the method for slope face improvement of the
present invention, a primer layer is preferably formed between the
protective layer and the lifespan-extending layer.
[0015] According to the method for slope face improvement of the
present invention, a topcoat layer is preferably formed on the
lifespan-extending layer.
[0016] According to the method for slope face improvement of the
present invention, the polymer compound is preferably at least one
selected from the group consisting of: polyurethane resin, polyurea
resin, epoxy resin and acrylic resin.
Advantage of the Invention
[0017] According to the present invention, a coating layer having
crack-following properties of 0.8 mm or greater, salt-blocking
properties and neutralization-preventing properties is formed as a
lifespan-extending layer on the surface of a protective layer
comprising mortar or concrete sprayed on a slope face, and as a
result, it is possible to prevent penetration of rainwater and the
like from cracks that form in the protective layer, restrict
degradation such as salt damage or neutralization of the protective
layer, and also prevent detachment of the protective layer caused
by the degradation; it is thus possible to envision a longer
lifespan for the protective layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic diagram illustrating the method for
slope face improvement according to a mode of embodiment, and shows
a cross section parallel to the height direction of terrain having
a cliff face or a slope face;
[0019] FIG. 2 is a schematic diagram illustrating the method for
slope face improvement according to a mode of embodiment, shows a
cross section parallel to the height direction of terrain having a
cliff face or a slope face, and is an enlargement of part of FIG.
1; and
[0020] FIG. 3 is a front view illustrating an example of the method
for slope face improvement according to a mode of embodiment, in
which visual guidance serving as a safety measure is provided by a
topcoat layer.
MODE OF EMBODIMENT OF THE INVENTION
[0021] A mode of embodiment of the method for slope face
improvement according to the present invention will be
described.
[0022] It should be noted that this mode of embodiment is
specifically described in order to provide a better understanding
of the essential point of the present invention and does not limit
the present invention unless particularly indicated otherwise.
[0023] FIG. 1 is a schematic diagram illustrating the method for
slope face improvement according to this mode of embodiment, and
shows a cross section parallel to the height direction of terrain
having a slope face. FIG. 2 is a schematic diagram illustrating the
method for slope face improvement according to this mode of
embodiment, shows a cross section parallel to the height direction
of terrain having a slope face, and is an enlargement of part of
FIG. 1.
[0024] In FIG. 1 and FIG. 2, the reference symbol 1 denotes a
foundation, 1a denotes a slope face (cliff face), 2 denotes a
protective layer comprising mortar or concrete; 3 denotes a
lifespan-extending layer; 4 denotes a primer layer; and 5 denotes a
topcoat layer. It should be noted that the primer layer 4 and the
topcoat layer 5 may be used as required.
[0025] The method for slope face improvement according to this mode
of embodiment is a method in which the lifespan-extending layer 3
is layered on a surface 2a of the protective layer 2 comprising
mortar etc. sprayed on the slope face 1a of the foundation 1,
whereby penetration of rainwater etc. from cracks that form in the
protective layer 2 is prevented, degradation of the protective
layer 2 is restricted, and detachment of mortar pieces or concrete
pieces from the protective layer 2 is prevented, a coating layer
having crack-following properties of 0.8 mm or greater,
salt-blocking properties and neutralization-preventing properties
being formed as the lifespan-extending layer 3.
[0026] The lifespan-extending layer 3 sustains and reinforces the
protective layer 2 and thereby extends the lifespan (useful life)
thereof (prolongs the life thereof).
[0027] The protective layer 2 is a layer comprising conventional
mortar or concrete which is sprayed in order to protect the slope
face 1a of the foundation 1 and to prevent the slope face 1a from
become unstable.
[0028] It should be noted that the slope face 1a may equally be a
cliff face when the foundation 1 is a cliff.
[0029] The coating layer forming the lifespan-extending layer 3 has
crack-following properties of 0.8 mm or greater, as defined in
Structure Construction Management (July 2015 edition, 3-6:
Concrete, 3-6-2: Surface Protection Requirement Performance, Nippon
Expressway Research Institute Company Limited), and preferably 5 mm
or greater, more preferably between 1 mm and 10 mm.
[0030] If the crack-following properties have a value of less than
0.8 mm, the crack-following properties of the coating layer with
respect to changes caused by degradation over time of the
protective layer 2 comprising mortar etc. are inadequate, and it is
not possible to obtain an adequate effect in terms of the lifespan
of the protective layer 2 afforded by the lifespan-extending layer
3.
[0031] The coating layer forming the lifespan-extending layer has
salt-blocking properties of no greater than 3.7.times.10.sup.-5
mg/cm.sup.2day, as defined in the "Quality Standard Test Method JHS
417-1999 for Concrete Coating Materials" of Structure Construction
Management of the Japan Highway Public Corporation, and the coating
layer has excellent salt-blocking properties if the defined value
satisfies no greater than 5.0.times.10.sup.-3 mg/cm.sup.2day. That
is to say, the coating layer which is a reinforcing layer 3 has a
considerable effect in terms of blocking salts such as calcium
chloride used as a snow-melting agent, and can prevent corrosion of
the protective layer 2 caused by said salts.
[0032] The coating layer forming the lifespan-extending layer 3 is
such that the neutralization-preventing properties defined in
Structure Construction Management (July 2015 edition, 3-6:
Concrete, 3-6-2: Surface Protection Requirement Performance, Nippon
Expressway Research Institute Company Limited), are 1 mm or less in
terms of neutralization depth.
[0033] The thickness of the lifespan-extending layer 3 is
preferably 1 mm to 2 mm.
[0034] If the thickness of the lifespan-extending layer 3 is within
this range, it is possible to achieve salt-blocking properties in
the lifespan-extending layer 3 of no greater than
3.7.times.10.sup.-5 mg/cm.sup.2day.
[0035] The coating layer forming the lifespan-extending layer 3
preferably comprises a polymer compound able to satisfy the
abovementioned crack-following properties, salt-blocking properties
and neutralization-preventing properties.
[0036] Furthermore, the polymer compound is preferably at least one
selected from the group consisting of: acrylic resin, epoxy resin,
polyester resin, polyurethane resin, polyurea resin, acrylic
urethane resin, asphalt urethane resin and asphalt.
[0037] These polymer compounds may be used alone or two or more
types may be mixed for use.
[0038] For example, when a slope face 1 facing a road is
constructed, a preferred polymer material which may be used is an
ultra-fast-curing polyurethane resin or polyurea resin etc. which
constitutes a material that cures rapidly, in order to shorten
construction time and lift lane restrictions on a road caused by
one-way traffic.
[0039] The lifespan-extending layer 3 is constructed over a large
surface area with respect to the slope face 1a of the foundation 1,
and therefore it is necessary to form the lifespan-extending layer
3 efficiently. The curing time after spraying of mortar etc. is
between 4 and 28 days, so it is difficult to shorten the
construction time. In contrast to this, ultra-fast-curing
polyurethane resin or polyurea resin has a curing time after
coating of 1 day, and therefore it is possible to shorten the
construction time. It is therefore possible to efficiently
construct the lifespan-extending layer 3 on the slope face 1a of
the foundation 1 by using an ultra-fast-curing polyurethane resin
or polyurea resin.
[0040] There is no particular limitation as to the method for
applying the coating layer that forms the lifespan-extending layer
3 on the surface 2a of the protective layer 2 or on a surface
(referred to below as "the surface") 4a on the opposite side to the
face of the primer layer 4 in contact with the protective layer 2,
but according to an exemplary method which may be cited, a coating
composition comprising a polymer compound that forms the coating
layer is applied to the surface 2a of the protective layer 2 or to
the surface 4a of the primer layer 4 by means of a two-liquid
impact agitation/mixing-type spray gun or a static mixer-type spray
gun. In particular, when an ultra-fast-curing polyurethane resin is
applied by means of a spray gun, the coating film may be formed by
supplying to the spray gun a curable mixture obtained by mixing an
isocyanate component and a polyol component, and applying this to
the surface 2a of the protective layer or the surface 4a of the
primer layer 4, or the isocyanate component and the polyol
component may be separately supplied to the spray gun, and a
mixture obtained by mixing of said components inside the spray gun
may be applied to the surface 2a of the protective layer 2 or to
the surface 4a of the primer layer 4 in order to form the coating
layer.
[0041] The primer layer 4 preferably has affinity with the
lifespan-extending layer 3 and the protective layer 2 comprising
mortar etc., and there may also be cases in which the surface 2a of
the protective layer 2 is whetted, so said primer layer is
preferably able to bond to a wet surface. Specific examples of
primers forming the primer layer 4 which may be advantageously used
include primers comprising epoxy resin or urethane resin which
cures at normal temperature, and these primers may be single-liquid
curable primers or two-liquid curable primers.
[0042] Furthermore, the primer layer 4 may be omitted if there is
adequate bonding between the protective layer 2 and the
lifespan-extending layer 3.
[0043] The topcoat layer 5 is formed with the aim of protecting the
lifespan-extending layer 3 (improving the weatherability thereof),
harmonizing with the landscape and providing visual guidance
serving as a safety measure. Examples of the polymer compound
forming the topcoat layer 5 which may be used include a two-liquid
curable solvent-based acrylic urethane resin, a two-liquid curable
aqueous acrylic urethane resin, an aqueous acrylic resin, and an
organo-siloxane resin.
[0044] The topcoat layer 5 is normally formed with the aim of
protecting the lifespan-extending layer 3, but as shown in FIG. 3,
it may equally be provided as a different-colored region 6 having a
different color from the lifespan-extending layer 3, on the
opposite surface (referred to below as "the surface") 3a to the
surface of the lifespan-extending layer 3 facing the protective
layer 2. As shown in FIG. 3, the different-colored region 6 is
depicted as an arrow or the like for visual guidance indicating the
direction of travel on a road (see FIG. 1) running along the slope
face 1a. There is no particular limitation as to the shape, size
(area) or number of different-colored regions 6, and these may be
suitably adjusted in accordance with the information (travel
direction or warning about a slope failure, or landslide etc.)
represented by said different-colored regions 6.
[0045] Furthermore, when the different-colored region 6 is formed,
a mixture in which a colored pigment commensurate with the aim is
mixed with the polymer compound forming the topcoat layer 5 may be
used, and said mixture may be applied to the surface 3a of the
lifespan-extending layer 3 as a distinct color from the
lifespan-extending layer 3 in order to form the different-colored
region 6.
[0046] There is no particular limitation as to the method for
coating the polymer compound forming the topcoat layer 5 on the
surface 3a of the lifespan-extending layer 3, but examples of
methods which may be cited include applying the polymer compound to
the surface 3a of the lifespan-extending layer 3 by means of a
roller, a brush or a spray gun et cetera.
[0047] According to the method for slope face improvement of this
mode of embodiment, dirt and foreign material adhering to the
surface 2a of the protective layer 2 comprising mortar etc. are
first of all completely removed. Furthermore, if there are
protrusions or differences in level etc. on the surface 2a of the
protective layer 2, said surface 2a is preferably smoothed by
making combined use of power tools and manual tools.
[0048] In addition, after the whole of the region of the surface 2a
of the protective layer 2 on which the lifespan-extending layer 3
is formed (the forming surface) has been smoothed, the forming
surface is preferably cleaned by means of a brush or air blowing
etc. in order to completely remove dirt and foreign material.
[0049] The primer layer 4 is then formed by coating a primer on the
cleaned surface 2a of the protective layer 2.
[0050] It should be noted that this mode of embodiment illustrates
a case in which the primer layer 4 is provided, but this does not
limit the present invention and it is equally possible to omit the
primer layer 4 if adhesion between the protective layer 2 and the
lifespan-extending layer 3 is adequate by virtue of the surface
state of the surface 2a of the protective layer 2 etc.
[0051] A coating composition comprising the polymer compound
constituting the coating layer that forms the lifespan-extending
layer 3 is then coated on the surface 2a of the protective layer 2
or on the surface 4a of the primer layer 4, and said coating
composition is cured in order to form the lifespan-extending layer
3.
[0052] The coating composition comprising the polymer compound that
forms the topcoat layer 5 is coated on the surface 3a of the
lifespan-extending layer 3, and said coating composition is cured
in order to form the topcoat layer 5, whereby construction is
completed.
[0053] According to the method for slope face improvement of this
mode of embodiment, the coating layer having crack-following
properties of 0.8 mm or greater, salt-blocking properties and
neutralization-preventing properties is formed as the
lifespan-extending layer 3 on the surface 2a of the protective
layer 2 comprising mortar etc. sprayed on the slope face 1a of the
foundation 1, and as a result it is possible to prevent penetration
of rainwater and the like from cracks that form in the protective
layer 2, restrict degradation such as salt damage or neutralization
of the protective layer, and also prevent detachment of the
protective layer caused by the degradation. Furthermore, the
resulting lifespan-extending layer 3 makes it possible to prevent
penetration of rainwater etc. from cracks that form in the
protective layer 2, and also has a punching strength of 0.3 kN or
greater (Structure Construction Management (July 2015 edition, 3-6:
Concrete, 3-6-2: Surface Protection Requirement Performance, Nippon
Expressway Research Institute Company Limited)) which is able to
prevent detachment of the protective layer 2. Furthermore, the
lifespan-extending layer 3 has a large effect in terms of blocking
salts such as calcium chloride used as a snow-melting agent, so it
is possible to prevent degradation of the protective layer 2
comprising mortar etc. caused by said salts. As a result, it is
possible to prevent degradation of the protective layer 2 and
detachmant of the mortar etc., and thus it is possible to envision
a longer lifespan for the protective layer 2.
[0054] Furthermore, according to the method for slope face
improvement of this mode of embodiment, the different-colored
region 6 is formed on the surface 3a of the lifespan-extending
layer 3, and as a result it is possible to provide a notification
of information relating to the environment around the slope face 1a
(travel direction on the road 11 running along the slope face 1a,
warning about a slope failure or landslide etc.). Furthermore, by
forming the lifespan-extending layer 3, the protective layer 2
comprising mortar etc. is not directly exposed to wind and rain
(snow and rain), so it is possible to prevent staining of the
protective layer 2 and adhesion of contaminants, and therefore the
esthetic appearance of the slope face 1a can be maintained.
EXEMPLARY EMBODIMENT
[0055] The present invention will be described in more specific
terms below through an exemplary embodiment and comparative
examples, but the present invention is not limited to the following
exemplary embodiment.
Exemplary Embodiment
[0056] The surface of a protective layer comprising existing mortar
that had deteriorated was cleaned in order to remove dirt and
foreign material etc., after which a modified epoxy resin primer
(commercial name: Resi-Primer PW-F, produced by Diflex) was applied
over the protective layer in a coating amount of 0.2 kg/m.sup.2,
and a primer layer having a thickness of 65 .mu.m was formed.
[0057] A two-liquid ultra-fast-curing polyurethane resin
(commercial name: CV Spray, produced by Diflex) was then applied by
means of a spray gun over the primer layer in a coating amount of
1.0 kg/m.sup.2, and a lifespan-extending layer having a thickness
of 1000 .mu.m was formed.
[0058] A two-liquid solvent-based acrylic urethane resin
(commercial name: Resi-Top, produced by Diflex) was then applied by
means of a spray gun over the lifespan-extending layer in a coating
amount of 0.15 kg/m.sup.2, and a topcoat layer having a thickness
of 47 .mu.m was formed.
[0059] The features of the method for slope face improvement
according to the exemplary embodiment are shown in table 1.
Comparative Example 1
[0060] A protective layer comprising existing mortar that had
deteriorated was stripped away from a slope face on a foundation by
human power and by machine, after which mortar was sprayed on the
slope face in the same way as had been done with the existing
protective layer in order to form a protective layer comprising
mortar, whereby the slope face was repaired.
[0061] The features of the method for slope face improvement
according to Comparative Example 1 are shown in table 1.
Comparative Example 2
[0062] The surface of a protective layer comprising existing mortar
that had deteriorated was cleaned in order to remove dirt and
foreign material etc., after which a polymer cement (commercial
name: Bask, produced by Nichimaru Co.) was used to form a secondary
protective layer comprising the polymer cement having a thickness
of 2000 .mu.m, whereby the slope face was repaired.
[0063] The features of the method for slope face improvement
according to Comparative Example 2 are shown in table 1.
Comparative Example 3
[0064] Short fibers comprising steel fibers or organic fibers were
disposed on the surface of a protective layer comprising existing
mortar that had deteriorated, and mortar was sprayed in the same
way as had been done with the existing protective layer from above
said short fibers in order to form a protective layer comprising
mortar, whereby the slope face was repaired.
[0065] The features of the method for slope face improvement
according to Comparative Example 3 are shown in table 1.
TABLE-US-00001 Exemplary Comparative Comparative Comparative
Embodiment Example 1 Example 2 Example 3 Cost Low High Low Medium
Construction time Low High Low Medium Useful life (years) 20 20 20
20 Performance Crack-following High None Low None properties (1-10
mm) (0-0.5 mm) Salt-blocking High None Low None properties
Water-blocking High Low Low Low properties Neutralization- High
None Low None preventing properties Environment CO.sub.2 emission
Low High because Low because High because amount because of
treatment small of large small and machinery machinery machinery
transportation was used used was used of waste material from
removing existing mortar etc. Noise Low High Low High Road Small-
Large-scale Small-scale Large-scale restrictions scale traffic
traffic restrictions restrictions because of because of heavy heavy
machinery used machinery used Construction/ Management Few types
Many types of Few types Many types Management of work work of work
of work Construction Short Long Short Long period Ease of Simple
Complex Simple Complex construction Ease of Possible Difficult
Difficult Difficult construction (winter season) Construction Small
Large Small Medium restrictions
[0066] It is clear from table 1 that the lifespan-extending layer
formed by means of the method for slope face improvement according
to the exemplary embodiment on the surface of the protective layer
comprising existing mortar that had deteriorated was superior in
terms of crack-following properties, salt-blocking properties,
water-blocking properties and neutralization-preventing properties
in comparison with the protective layers formed by means of the
slope face improvement methods according to Comparative Examples
1-3 on the surface of protective layers comprising existing mortar
that had deteriorated. Furthermore, the method for slope face
improvement according to the exemplary embodiment not only made it
possible to repair the slope face in a shorter construction period
and at a lower cost than in the case of the methods for slope face
improvement according to Comparative Examples 1-3, the method
according to the exemplary embodiment was also clearly superior
from an environmental perspective in terms of lower carbon dioxide
emissions and less noise etc.
FIELD OF INDUSTRIAL APPLICATION
[0067] It is possible to improve safety and maintenance properties
by suppressing degradation of a protective layer on a cliff face or
slope face etc.
KEY TO SYMBOLS
[0068] 1 . . . Foundation [0069] 1a . . . Slope face [0070] 2 . . .
Protective layer [0071] 3 . . . Lifespan-extending layer [0072] 4 .
. . Primer layer [0073] 5 . . . Topcoat layer [0074] 6 . . .
Different-colored region [0075] 11 . . . Road
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