U.S. patent application number 12/537927 was filed with the patent office on 2010-06-17 for inorganic matrix-fabric system and method.
This patent application is currently assigned to Saint-Gobain Technical Fabrics Canada, LTD.. Invention is credited to Corina-Maria Aldea, David Geraint Roberts.
Application Number | 20100147449 12/537927 |
Document ID | / |
Family ID | 31187058 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100147449 |
Kind Code |
A1 |
Aldea; Corina-Maria ; et
al. |
June 17, 2010 |
INORGANIC MATRIX-FABRIC SYSTEM AND METHOD
Abstract
A method of reinforcing a structural support, includes applying
a reinforcement system comprising an AR-glass fibrous layer
embedded in an inorganic matrix to the structural support. The
AR-glass fibrous layer has a sizing applied thereon, and a resinous
coating applied is applied over the sizing. The inorganic matrix is
adherent to the resinous coating and the resinous coating is
adherent to the sizing.
Inventors: |
Aldea; Corina-Maria;
(Ontario, CA) ; Roberts; David Geraint;
(Youngstown, NY) |
Correspondence
Address: |
DUANE MORRIS LLP - Philadelphia;IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103-4196
US
|
Assignee: |
Saint-Gobain Technical Fabrics
Canada, LTD.
Ontario
CA
|
Family ID: |
31187058 |
Appl. No.: |
12/537927 |
Filed: |
August 7, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11071126 |
Mar 3, 2005 |
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12537927 |
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10209471 |
Jul 30, 2002 |
7311964 |
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11071126 |
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Current U.S.
Class: |
156/242 ;
156/280; 156/60 |
Current CPC
Class: |
E04G 2023/0251 20130101;
Y10T 29/49618 20150115; Y10T 428/249928 20150401; Y10T 428/249946
20150401; Y10T 428/249948 20150401; Y10T 428/24994 20150401; Y10T
428/249924 20150401; C04B 14/42 20130101; C04B 32/02 20130101; Y10T
428/249932 20150401; C04B 20/023 20130101; E04G 23/0218 20130101;
B32B 17/04 20130101; Y10T 156/10 20150115; C04B 28/02 20130101;
C03C 25/103 20130101; C04B 28/02 20130101; C03C 25/1095 20130101;
Y10T 428/249929 20150401 |
Class at
Publication: |
156/242 ; 156/60;
156/280 |
International
Class: |
B32B 38/00 20060101
B32B038/00 |
Claims
1. A method of reinforcing a structural support, comprising
applying a reinforcement system comprising an AR-glass fibrous
layer embedded in an inorganic matrix to the structural support,
wherein said AR glass fibrous layer has a sizing applied thereon,
and a resinous PVC plastisol coating applied over said sizing, said
inorganic matrix being adherent to said resinous coating, and said
resinous coating being adherent to said sizing.
2. The method of claim 1, wherein the fibrous layer is a
bi-directional open fibrous layer having two rovings per inch in a
weft direction and one roving per inch in a warp direction
3. The method of claim 1, wherein the fibrous layer is a
bi-directional open fibrous layer having one roving in a weft
direction and one roving in a warp direction.
4. The method of claim 1, wherein the fibrous layer is comprised of
AR-glass yarns.
5. The method of claim 1, wherein the fibrous layer is formed by
needling, weaving, knitting, or adhesive bonding of cross laid
mesh.
6. The method of claim 1, wherein the fibrous layer is formed from
continuous or discontinuous fibers randomly oriented in a non-woven
mat.
7. The method of claim 1, wherein the inorganic matrix comprises a
cementitious material.
8. The method of claim 7, wherein in the inorganic matrix includes
a resin which forms an adhesive bond with said resinous
coating.
9. The method of claim 1, wherein the cementitious material
includes chopped alkali-resistant glass fibers.
10. The method of claim 1, wherein the coating comprises at least
one polymer containing one or more of an acrylate and a vinyl
chloride.
11. The method of claim 1, wherein the structural support is
comprised of an unreinforced masonry.
12. The method of claim 1, wherein the structural support is
comprised of concrete.
13. The method of claim 1, wherein the structural support is
comprised of bricks.
14. The method of claim 1, wherein the inorganic matrix is applied
in two or more layers.
15. The method of claim 1, wherein the sizing comprises a blend of
anhydrous polymerized epoxy amine, vinyl and amine coupling agents
and a non-ionic surfactant
16. A method of reinforcing a structural support, comprising:
applying a first layer of an inorganic matrix to the structural
support; embedding a first AR-glass open fibrous layer into the
matrix, said AR-glass fibrous layer having a sizing applied
thereon, and a resinous coating applied over said sizing, said
inorganic matrix being adherent to said resinous PVC plastisol
coating, and said resinous coating being adherent to said sizing;
and applying a second layer of the inorganic matrix to the first
AR-glass open fibrous layer.
17. The method of claim 16, wherein the steps of applying a first
and second layer of the inorganic matrix includes trowelling the
matrix.
18. The method of claim 16, wherein the fibrous layer is embedded
into the matrix by hand.
19. The method of claim 16, further comprising: embedding a second
AR-glass fibrous layer into the second layer of matrix; and
applying a third layer of the inorganic matrix to the second
AR-glass fibrous layer.
20. The method of claim 16, further comprising: embedding a third
AR-glass fibrous layer into the third layer of the inorganic
matrix, and applying a fourth layer of the inorganic matrix to the
third AR-glass fibrous layer.
21. The method of claim 19, wherein the first and second fibrous
layer is a bi-directional fibrous layer comprising two rovings of
fibers per inch in the weft direction and one roving of fibers per
inch in the warp direction.
22. The method of claim 21, wherein one of the first or second
fibrous layers is orientated so that the weft direction is parallel
to the bottom of the support structure and the other of the first
or second fibrous layers is orientated so that the weft direction
is perpendicular to the bottom of the support structure.
23. The method of claim 21, wherein one of the first or second
fibrous layers is oriented at a clockwise 45.degree. angle to the
bottom of the structural support and the other of the first or
second fibrous layers is oriented at a counterclockwise 45.degree.
to the bottom of the structural support.
24. The method of claim 20, wherein each of the first, second and
third fibrous layer is a bi-directional fibrous layer comprising
two rovings of fibers in the weft direction and one roving of
fibers in the warp direction, and wherein one of the fibrous layers
is oriented at a clockwise 45.degree. angle to the bottom of the
structural support, one of the fibrous layers is oriented at a
counterclockwise 45.degree. angle to the bottom of the structural
support, and one of the fibrous layers is oriented so that the weft
direction of the fibrous layer is parallel to the bottom of the
structural support.
25. The method of claim 16, wherein the layers of inorganic matrix
are approximately 1/8 inch thick.
26. The method of claim 16, wherein the wetting step comprises
spraying the structural support with water.
27. The method of claim 16, further comprising wetting the
structural support, and wherein the step of wetting the structural
support is performed prior to applying the first layer of inorganic
matrix.
28. The method of claim 16, wherein the sizing comprises a blend of
anhydrous polymerized epoxy amine, vinyl and amine coupling agents
and a non-ionic surfactant.
29. A method of reinforcing a structural support, comprising:
applying a first layer of an inorganic matrix to the structural
support; embedding a first AR-glass open fibrous layer into the
matrix, said AR-glass fibrous layer having a resinous PVC plastisol
coating applied thereon, said inorganic matrix being adherent to
said resinous PVC plastisol coating; applying a second layer of the
inorganic matrix to the first AR-glass open fibrous layer;
embedding a second AR-glass fibrous layer into the second layer of
matrix; and applying a third layer of the inorganic matrix to the
second AR-glass fibrous layer; wherein the first and second fibrous
layer is a bi-directional fibrous layer, and wherein one of the
first or second fibrous layers is orientated so that the weft
direction is parallel to the bottom of the support structure and
the other of the first or second fibrous layers is orientated so
that the weft direction is perpendicular to the bottom of the
support structure.
30. The method of claim 1, wherein the AR-glass fibrous layer has
AR glass fibers comprising about 25% of Zirconia.
31. The method of claim 1, wherein said AR-glass fibrous layer is
formed by the steps of: applying the sizing on AR glass fibers
before forming the AR glass fibers into the fibrous layer, and
applying the resinous coating over the fibrous layer forming the AR
glass fibers into the fibrous layer.
32. The method of claim 29, wherein the AR glass fibrous layer is
formed from AR glass fibers having a sizing applied thereon before
forming the AR glass fibers into the fibrous layer, the sizing
comprising a blend of anhydrous polymerized epoxy amine, vinyl and
amine coupling agents and a non-ionic surfactant.
33. The method of claim 1, wherein the coating further comprises a
water resistant additive, from the group consisting of paraffin, a
combination of paraffin and ammonium salt, fluoro chemicals,
organohydrognpolysiloxanes, wax asphalt emulsions and polyvinyl
alcohol, and polyvinyl acetate.
34. The method of claim 33, wherein the coating further comprises
one of the group consisting of bromated phosphorous complex,
halogenated paraffin, colloidal antimony pentoxide, borax,
unexpanded vermiculate, clay, colloidal silica and colloidal
aluminum.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/071,126, filed Mar. 3, 2005, which is a
division of U.S. patent application Ser. No. 10/209,471, filed Jul.
30, 2002, now U.S. Pat. No. 7,311,964, the entire disclosures of
which are incorporated by reference herein in their entireties.
FIELD OF THE INVENTION
[0002] This invention relates to structural supports, and more
particularly to a method and reinforcement system for strengthening
of such structural supports.
BACKGROUND OF THE INVENTION
[0003] Walls, columns and other structures constructed of materials
such as concrete or cement paste, brick or masonry units, and the
like are widely used as support structures. Tunnels, building
structural supports, bridge supports, freeway overpass supports and
parking structure supports are just a few of the many uses for
these cementitious structural supports. These supports may exist in
a wide variety of shapes with circular, square and rectangular
cross-sections being the most common. However, numerous other
cross-sectional shapes have been used, including regular polygonal
shapes and irregular cross-sections. The size of structural
supports also varies greatly depending upon the intended use.
Structural supports having heights and lengths exceeding 50 feet
are commonly used in various applications.
[0004] It is common practice to reinforce concrete structural
supports with steel rods, mesh, or bars. The steel reinforcement
provides a great deal of added structural strength (e.g.,
compression, tensile, flexural and/or shear-resistance) to the
support, but there have been numerous incidents of structural
failure of these supports when subjected to asymmetric loads and
horizontal displacement generated during earthquakes or explosions.
Concrete structures, while adequate in compression, are subject to
cracking, collapse, and partial loss due to stresses associated
with earthquakes, explosions, land subsidence and overloading.
Structural failure of such structures can have devastating
consequences. Accordingly, there is a continuing need to enhance
the ability of reinforced and unreinforced concrete and cement
structural supports to withstand the asymmetric loads and
horizontal displacements which are applied during an earthquake or
explosion.
[0005] One way of increasing the structural integrity of support
structures is to include additional metal reinforcement prior to
forming the structural support. Other design features may be
incorporated into the support structure fabrication in order to
increase its resistance to asymmetric loading or horizontal
displacement. However, there are hundreds of thousands of existing
structural supports located in earthquake prone areas, which do not
have adequate metal reinforcement or structural design to withstand
high degrees of asymmetric loading or horizontal displacement.
Accordingly, there is a need to provide a simple, efficient and
relatively inexpensive system for reinforcing such existing
structural supports to prevent or reduce the likelihood of failure
during an earthquake or explosion.
[0006] One approach to reinforcing cementitious structures, such as
concrete columns, is to wrap the exterior surface of the structure
with a composite reinforcement layer, or fabric reinforced plastic
(FRP). In U.S. Pat. No. 5,607,527 to Isley, Jr., a composite
reinforcement layer having at least one fabric layer located within
a resin matrix is wrapped around the exterior surface of a concrete
column. The fabric layer has first and second parallel selvedges
that extend around the circumferential outer surface of the column
in a direction substantially perpendicular to the column axis.
Preferred fibers disclosed by Isley include ones made from glass,
polyaramid, graphite, silica, quartz, carbon, ceramic and
polyethylene. Suitable resins suggested by this patent include
polyester, epoxy, polyamide, bismaleimide, vinylester, urethanes,
and polyurea, with epoxy-based resins being preferred.
[0007] Another approach to reinforcing a cementitious structural
support is disclosed in U.S. Pat. No. 6,017,588 to Watanabe, et al.
This patent discloses using an FRP to reinforce a structural
support by forming a primer layer on the surface of the support
structure, forming, if necessary, a putty layer on the primer
layer, applying an impregnating resin on the primer layer (or putty
layer) before, after or, before and after, cladding with fiber
sheets to allow the resin to penetrate into the spaces in the fiber
sheets, followed by curing the resin, the primer, putty and
impregnating resin. The primer, putty and impregnating resin of
this reference all include a resin composition. The disclosed fiber
sheets may include carbon, aramid or glass fibers. The asserted
advantage of the reinforcement structure of this patent is
increased adherence of the reinforcement to the surface of the
structural support.
[0008] Reinforcing FRP systems such as those described above can
often be flammable, toxic and difficult to handle during
application. They also provide, after curing, poor fire resistance,
poor bonding to the concrete or brick being reinforced, and poor
water/air permeability, resulting in the creation of moisture
accumulation. Additionally, they are fairly expensive and tend to
delaminate upon failure.
[0009] A repair or reinforcement system for existing support
structures or for new construction support structures is
needed.
SUMMARY OF THE INVENTION
[0010] In accordance with a first preferred embodiment of the
present invention, a method for reinforcing a structural support is
provided. This method comprises applying a reinforcement system
having an alkali-resistant fibrous layer embedded in an inorganic
matrix to a structural support.
[0011] The preferred alkali-resistant fibrous layer is comprised of
AR-glass having a sizing applied thereon, and a resinous coating
applied over the sizing, the inorganic matrix being adherent to the
resinous coating and the resinous coating being adherent to the
sizing. Unlike other types of glass fibers, such as E-glass,
AR-glass has a high degree of resistance to alkali attack and
higher strength retention over time. This is due to the presence of
an optimum level of Zirconia (ZrO.sub.2) in the glass fibers. This
type of glass exhibits a high degree of chemical resistance,
resisting the very high alkalinity produced by the hydration of
conventional cementitious materials such as ordinary Portland
cement.
[0012] The preferred inorganic matrix is comprised of cementitious
material such as cement, concrete or mortar. More preferably the
inorganic matrix comprises ordinary Portland cement having chopped
reinforcing fibers dispersed throughout the cement. Such fibers may
include those made from carbon, AR-glass, cellulose, rayon or
polymeric materials, such as aramids, polyolefins, polyester, or
hybrids thereof, for example.
[0013] According to another embodiment of the present invention, a
method of reinforcing a structural support comprises a) applying a
first layer of an inorganic matrix to the structural support, b)
embedding a first AR-glass open fibrous layer into the matrix, said
AR-glass fibrous layer having a sizing applied thereon, and a
resinous coating applied over the sizing, the inorganic matrix
being adherent to the resinous coating, and the resinous coating
being adherent to the sizing, and c) applying a second layer of the
inorganic matrix to the first AR-glass open fibrous layer.
Additional fibrous layers and layers of inorganic matrix may also
be added.
[0014] According to another embodiment of the present invention, a
structural support system is provided including a structural
support, and a reinforcement system adhered to the structural
support, the reinforcement system comprising an AR-glass fibrous
layer embedded in an inorganic matrix, wherein the AR-glass fibrous
layer has a sizing applied thereon, and a resinous coating applied
over the sizing, the inorganic matrix being adherent to the
resinous coating, and the resinous coating being adherent to the
sizing.
[0015] According to a further embodiment of the present invention,
a method of reinforcing a structural support is provided comprising
applying a reinforcement system having a fibrous layer embedded in
an inorganic matrix to the structural support. The fibrous layer
comprises PVA fibers, carbon fibers, aramid fibers, or a
combination thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective cross-sectional view of a support
structure having an exemplary reinforcement system according to the
present invention.
[0017] FIG. 2 is a partial cross-sectional view of a support
structure having one embodiment of the reinforcement system of the
present invention.
[0018] FIG. 3 is a front view of a concrete masonry unit (CMU) wall
sample used in testing alternative embodiments of the reinforcement
system of the present invention.
[0019] FIG. 4 is a front view of a wall sample mounted in a test
frame.
[0020] FIG. 5 is a diagram of a wall sample and test frame showing
locations of displacement measurements and directions of horizontal
and vertical forces.
[0021] FIG. 6 is a front view of wall sample 1 showing crack growth
during in-plane shear testing.
[0022] FIG. 7 is a graph showing a backbone curve of load versus
displacement for the wall sample 1 and the backbone curve for the
control sample.
[0023] FIG. 8 is a front view of wall sample 2 showing crack growth
during in-plane shear testing.
[0024] FIG. 9 is a graph showing a backbone curve of load versus
displacement for the wall sample 2 and the backbone curve for the
control sample.
[0025] FIG. 10 is a front view of wall sample 3 showing crack
growth during in-plane shear testing.
[0026] FIG. 11 is a graph showing a backbone curve of load versus
displacement for the wall sample 3 and the backbone curve for the
control sample.
[0027] FIG. 12 is a perspective view of a triplet sample having an
exemplary reinforcement system according to the present
invention.
[0028] FIG. 13 is a graph showing a plot of load versus crosshead
displacement for the triplet tests.
[0029] FIG. 14 illustrates different configurations of
fiber-reinforced-polymer (FRP) reinforcement systems applied to
wall samples tested under conditions similar to those employed in
testing Walls 1-3.
[0030] FIG. 15 is a graph comparing the engineering load increases
for wall samples 1-3 to wall samples having FRP reinforcement
systems applied in the different configurations shown in FIG. 14,
versus the control sample having no reinforcement.
[0031] FIG. 16 is a graph comparing the wall displacements for wall
samples 1-3 with each other and also to previously tested FRP
reinforced wall samples.
DETAILED DESCRIPTION
[0032] A reinforcement system and a method of reinforcing a
structural support using the reinforcement system of the present
invention are provided. The reinforcement system has improved
bonding with a cementitious support structure and is less likely to
delaminate from the structural support than existing reinforcement
systems.
[0033] In accordance with the present invention, the following
terms are defined:
[0034] Adhesive bonded crossed laid fibers/mesh. Woven fabrics
consisting of layers of parallel textile yarns superimposed on each
other at acute or right angles. These layers are bonded at the
intersections of the yarns by an adhesive, glue or by thermal
bonding.
[0035] Cementitious material/composite. An inorganic hydraulically
setting material, such as those containing portland cement, mortar,
plaster, fly ash, slag, silica fume, metakaolin, gypsum, geopolymer
and/or other ingredients, such as aggregate, including sand or
gravel, additives or admixtures, such as foaming agents, resins,
including acrylic fortifiers, moisture resistant additives,
shrinkage reducing admixtures (SRA), air-entraining (AE)
admixtures, fire retardants, and chopped fibers, including glass,
PVA, polypropylene, cellulose, graphite, or hybrids thereof.
[0036] Coatings/binders/finishes. Compounds, generally organic,
applied to fabrics after processing (e.g., weaving or knitting) to
protect the fibers and give the fabric stability.
[0037] Fiber. A general term used to refer to filamentary
materials. Often, fiber is used synonymously with filament. It is
generally accepted that a filament routinely has a finite length
that is at least 100 times its diameter. In most cases, it is
prepared by drawing from a molten bath, spinning, or by deposition
on a substrate.
[0038] Filament. The smallest unit of a fibrous material. The basic
units formed during drawing and spinning, which are gathered into
strands of fiber for use in composites. Filaments usually are of
extreme length and very small diameter. Some textile filaments can
function as a yarn when they are of sufficient strength and
flexibility.
[0039] Glass fiber. A fiber spun from an inorganic product of
fusion that has cooled to a rigid condition without
crystallizing.
[0040] Glass Filament. A form of glass that has been drawn to a
small diameter and long lengths.
[0041] Inorganic Matrix. A matrix material comprising mostly
inorganic ingredients, such as ceramics, glasses, cementitious
materials, and geopolymers (inorganic resins), for example.
[0042] Knitted fabrics. Fabrics produced by interlooping chains of
filaments, roving or yarn.
[0043] Mat. A fibrous material consisting of randomly oriented
chopped filaments, short fibers, or swirled filaments loosely held
together with a binder.
[0044] Roving. A number of continuous filaments, strands, or
collected into a parallel bundle.
[0045] Sizing. Compounds, generally organic, applied as a fine
coating to rovings after drawing of glass filaments in order to
bind the individual filaments together and stiffen them to provide
abrasion resistance during processing (e.g., weaving or
knitting).
[0046] Tensile strength. The maximum load or force per unit
cross-sectional area, within the gage length, of the specimen. The
pulling stress required to break a given specimen.
[0047] Tex. A unit for expressing linear density (or gauge) equal
to the weight in grams of 1 kilometer of yarn, filament, fiber or
other textile strand.
[0048] Warp. The yarn, fiber or roving running lengthwise in a
woven fabric. A group of yarns, fibers or roving in long lengths
and approximately parallel.
[0049] Warp knit. Warp knitting is a type of knitting in which the
yarns generally run lengthwise in the fabric.
[0050] Weave. The particular manner in which a fabric is formed by
interlacing yarns, fibers or roving. Weave can be further defined
by "type of weave", such as leno weave, for example.
[0051] Weft. The transverse threads or fibers in a woven fabric.
Those fibers running perpendicular to the warp. Also called fill,
filling yarn or woof.
[0052] Woven fabric. A material (usually a planar structure)
constructed by interlacing yarns, fibers, roving or filaments, to
form such fabric patterns as plain, harness satin, or leno
weaves.
[0053] Yarn. An assemblage of filaments, fibers, or strands, either
natural or manufactured, to form a continuous length that is
suitable for use in knitting, weaving or interweaving into textile
materials. The assemblage of filaments, fibers or strands may have
some or no twist.
[0054] Referring to FIG. 1, a reinforcement system 10 is shown
reinforcing a support structure 20. The present invention may be
used to reinforce a wide variety of support structures. Such
support structures may include, for example, walls, beams, exterior
insulation fabric systems ("EIFS") slabs, chimneys, stacks, tanks,
columns, silos, shafts, pipes, conduits, tunnels and the like. The
support structure may be planar, circular, or any other shape. The
invention is especially well suited for reinforcing support
structures comprised of cementitious or masonry materials such as
cement, concrete, brick, and cinder block, which may be reinforced
or unreinforced. One structural support especially suited for the
reinforcement system of the present invention is unreinforced
masonry (URM) walls.
[0055] The reinforcement system 10 comprises at least one
alkali-resistant open fibrous layer 12 (two fibrous layers are
shown in FIG. 1) and an inorganic matrix 14. The fibrous layers 12
are embedded within the matrix 14. The system 10 is applied to a
surface of the support structure 20.
[0056] The following detailed description and examples describe use
of the present invention to support a structure through application
to one surface of the structure; however, it will be understood by
those skilled in the art that the present invention is not limited
thereto, but may be applied to any number of surfaces depending on
the shape or type of support structure. Thus, for example, the
reinforcement system of the present invention may be applied to an
outside surface and an inside surface of a wall of a building,
pipe, wall or other structure.
[0057] The inorganic matrix 14 preferably comprises a cementitious
material, such as cement paste, mortar or concrete, and/or other
types of materials such as gypsum and geopolymers (inorganic
resins). More preferably the inorganic matrix comprises Portland
cement having chopped fibers dispersed throughout the cement.
Preferably the fibers are AR-glass fibers but may also include, for
example, other types of glass fibers, aramids, polyolefins, carbon,
graphite, polyester, PVA, polypropylene, natural fibers, cellulosic
fibers, rayon, and hybrids thereof. The inorganic matrix may
include other ingredients or additives such as fly ash, latex, slag
and metakaolin, resins, such as acrylics, polyvinyl acetate, or the
like, ceramics, including silicon oxide, titanium oxide, and
silicon nitrite, setting accelerators, water and/or fire resistant
additives, such as silioxane, borax, fillers, setting retardants,
dispersing agents, dyes and colorants, light stabilizers and heat
stabilizers, shrinkage reducing admixtures, air entraining agents,
or combinations thereof, for example. In a preferred embodiment,
the inorganic matrix includes a resin that may form an adhesive
bond with a resinous coating applied to the alkali-resistant open
fibrous layer.
[0058] Preferably the inorganic matrix has good bonding with the
support structure. Portland cement, for example, has excellent
bonding to concrete, bricks and concrete masonry units (CMUs). The
inorganic matrix may contain curing agents or other additives such
as coloring agents, light stabilizers and heat stabilizers, for
example.
[0059] One inner surface 16 of the inorganic matrix is preferably
in direct contact with a surface 22 of the support structure. Due
to the preferred compatibility of the inorganic matrix 14 with the
support structure 20, there is no requirement that any adhesive
material be applied between the two materials, however the addition
of an adhesive between, or among, the inorganic matrix and the
support structure is not precluded.
[0060] The alkali-resistant fibrous layers 12 are a reinforcement
material for the inorganic matrix 14. The fibrous layers 12
preferably provide long term durability to the reinforcement system
10 in the highly alkaline environment of the inorganic matrix where
the matrix is comprised of materials such as cement paste, mortar,
or concrete or geopolymers. The fibrous layers may be comprised of
glass fibers, PVA fibers, carbon fibers or aramid fibers, for
example, or any combination thereof. Most preferably, the fibrous
layers are comprised of AR-glass (alkali-resistant glass), such as
that manufactured by Saint Gobain Vetrotex under the trademark
Cem-FIL.RTM.. Unlike other types of glass fibers, such as E-glass,
AR-glass has a high degree of resistance to alkali attack and a
higher strength retention over time. This is due to the presence of
an optimum level of Zirconia (ZrO.sub.2), e.g. preferably about 10%
to about 25% ZrO.sub.2, in the glass fibers. This type of glass
exhibits a high degree of chemical resistance, resisting the very
high alkalinity produced by the hydration of cementitious materials
such as ordinary Portland cement. In addition, AR-glass has
superior strengthening properties necessary for use in earthquake
and explosion-resistant applications. It has high tensile strength
and modulus and does not rust. Although less preferred, other glass
fibers may be employed, such as E-glass, ECR-glass, C-glass,
S-glass and A-glass, which are not inherently alkali-resistant,
when such fibers are coated with an alkali-resistant material, such
as polyvinyl chloride resinous coating.
[0061] The preferred AR-glass fibers are preferably produced as
rovings or yarns. The linear density of the AR-glass fibers
preferably ranges from about 76 Tex where yarns are employed to
2,500 tex where rovings are employed. Where carbon fibers are used,
they are preferably provided as tows, with the filament count
preferably ranging from about 3,000 to 24,000. Preferred properties
of the AR-glass include a virgin filament tensile strength of at
least about 185,000 psi or higher, Young's modulus of elasticity of
about 10-12 million psi, strain at breaking point of at least about
1.5% or higher, water uptake at less than about 0.1%, and softening
temperature of about 860.degree. C.
[0062] The fibrous layers 12 may be formed, for example, by various
methods of weaving, such as plain or leno weave, or by knitting or
laying of continuous fibers. The fibrous layers may also be laid
scrim or be formed from discontinuous or continuous fibers randomly
oriented in a non-woven mat. Referring to FIG. 2, in one preferred
embodiment, the fibrous layers 12a and 12b are glass fiber
bi-directional fibrous layers having two rovings per inch of fibers
in one direction (e.g., the weft or fill direction) and one roving
per inch of fiber in a direction 90 degrees from the other
direction (e.g., the warp direction). (In another preferred
embodiment, the glass fiber bi-directional fibrous layers have one
roving per inch in each direction.) Varying fiber orientation,
concentration, and fiber type permits tailoring of strength to a
specific application. Using different methods of knitting, braiding
or weaving of the fabric may also be employed to produce a stronger
reinforcement. The openings 18 in the fibrous layer 12 (see FIG. 1)
should be sufficient to allow interfacing between the layers 14a-c
of the inorganic matrix 14 disposed on each side of the fibrous
layers 12a and 12b.
[0063] The fibrous layer also preferably includes a sizing.
Preferred sizings for use with a fibrous layer comprised of
AR-glass include aqueous sizings comprising one of the following
blends: 1) an epoxy polymer, vinyl and amine coupling agents and a
non-ionic surfactant; 2) an epoxy polymer, amine coupling agent and
a non-ionic surfactant; 3) an epoxy polymer, metacrylic and epoxy
coupling agents, and cationic and non-ionic surfactants (paraffin
lubricants); 4) anhydrous polymerized acrylate amine (for example,
the substance disclosed in PCT Patent Application No. WO 99/31025,
which is incorporated herein by reference), metacrylic and epoxy
coupling agents and a non-ionic surfactant; and 5) anhydrous
polymerized epoxy amine (for example, as disclosed in U.S. Pat. No.
5,961,684 to Moireau et al., which is incorporated herein by
reference), vinyl and amine coupling agents, and a non-ionic
surfactant, each of the above blends being produced by Cem FIL
Reinforcements of Saint Gobain Vetrotex Cem-FIL.RTM. S.L., a Saint
Gobain Vertrotex company. Preferably, the non-ionic surfactant
comprises an organo-silane. These sizings are compatible with the
preferred coatings for the AR-glass fibrous layer as described
below and the cementitious matrices, and improve initial glass
strength and ease of fabric forming. The sizings preferably
comprise not more than 2.5% by weight, and most preferably less
than 1.5% by weight of the fibrous layer.
[0064] The fibrous layers may also include an optional coating 24.
Coatings are preferred where the fibrous layer is comprised of
glass; however, coatings are not necessary where the fibrous layer
is comprised of AR-glass, PVA, carbon or aramid fibers. The coating
24 provides mechanical and chemical protection to the glass fibrous
layers 12. The coating is preferably an acrylate and/or vinyl
chloride containing a polymer or polymers. Coating 24 is preferably
acrylic or PVC plastisol, but may be poly vinyl alcohol (PVA),
styrene-butadiene rubber (SBR), polyolefin, acrylic acid,
unsaturated polyesters, vinyl ester, epoxies, polyacrylates,
polyurethanes, polyolefins, phenolics, and the like. Examples of
preferred coatings include an acrylic coating manufactured by
Saint-Gobain Technical Fabrics, a Saint-Gobain company, under the
label number 534 and a PVC plastisol coating manufactured by
Saint-Gobain Technical Fabrics under the label number V38. The use
of PVC plastisol as a coating further improves the alkali
resistance of the fibrous layer in the inorganic matrix. The use of
acrylic as a coating promotes adherence of the fibrous layer to
inorganic matrix, especially where the matrix includes acrylic.
[0065] The coating can further contain a water resistant additives,
such as, paraffin, and combination of paraffin and ammonium salt,
fluoro chemicals designed to impart alcohol and water repellency,
such as FC-824 from 3M Co., organohydrogenpolysiloxanes, silicone
oil, wax-asphalt emulsions and poly(vinyl alcohol) with or without
a minor amount of poly(vinyl acetate). In addition, the flame
retardants, such as bromated phosphorous complex, halogenated
paraffin, colloidal antimony pentoxide, borax, unexpanded
vermiculate, clay, colloidal silica and colloidal aluminum can be
added to the coating. Further, optional ingredients, such as
pigments, preservatives, dispersants, catalysts, fillers and the
like may be added to the coating.
[0066] The coating is preferably applied by dip-coating the fibrous
layer into the coating, but may applied by any other technique
known in the art, such as spraying, roll coating, and the like. The
wt % of the coating will depend on the type of coating, preferably
ranging from 10 to 200 wt % of the total weight of the coating and
fiber. The coating can be applied in various thicknesses.
Preferably the coating is applied so that no fibers of the fibrous
layer protrude from the coating, however, the coating may
alternatively be intermittently applied. After application of the
coating 24, the openings 18 in the fibrous layers 12a and 12b
should be sufficient to allow interfacing between the layers 14a-c
of the inorganic matrix 14 disposed on each side of the fibrous
layers.
[0067] According to a preferred embodiment of the present
invention, the sizing and coating of an AR-glass fibrous layer are
combined to optimize tensile performance and retention of tensile
strength after aging, and to improve compatibility between the
AR-glass, sizing, coating and cementitious matrix. Preferably the
coating 24 is adherent to the sizing and the inorganic matrix 14 is
adherent to the coating 24. A preferred combination includes a
sizing selected from the group consisting of 1) an epoxy polymer,
vinyl and amine coupling agents and a non-ionic surfactant; 2) an
epoxy polymer, amine coupling agent and a non-ionic surfactant; 3)
an epoxy polymer, metacrylic and epoxy coupling agents, and
cationic and non-ionic surfactants (paraffin lubricants); 4)
anhydrous polymerized acrylate amine, metacrylic and epoxy coupling
agents and a non-ionic surfactant; and 5) anhydrous polymerized
epoxy amine, vinyl and amine coupling agents, and a non-ionic
surfactant, and a polymeric coating selected from the group
consisting of acrylic and PVC plastisol. Table 1 shows the results
of tensile strength and tensile retention testing following a 5%
NaOH accelerated aging test, a Tri-alkali test (TAT) and a strand
in cement (SIC) test using various coating/sizing combinations, as
compared with uncoated AR-glass and E-glass.
TABLE-US-00001 TABLE 1 TENSILE PROPERTIES OF COATED AND UNCOATED
GLASS FIBERS Tensile Strength (g/tex) Tensile Retention (%) Aged
Aged Aged Retention Retention Retention Sizing Coating Unaged TAT
NaOH SIC TAT NaOH SIC Material type Label Type Label Type Initial
TAT NaOH SIC TAT NaOH SIC Cem-FIL 5197 5197.sup.1 aqueous none none
40.65 greige resin Cem-FIL 5197 V38 5197 aqueous V38.sup.2 PVC
60.14 61.24 57.05 101.83 94.86 resin plastisol Cem-FIL 5197 534
5197 aqueous 534.sup.3 acrylic 62.40 39.89 37.97 63.93 60.85 resin
Cem-FIL 019/2 V38 019/2.sup.4 aqueous V38 PVC 71.97 74.15 64.90
103.03 90.18 resin plastisol Cem-FIL 019/3 A15 019/3.sup.5 aqueous
A15.sup.6 PVA 57.75 39.58 68.54 resin Cem-FIL 020/2 K29 020/2.sup.7
anhydrous K29.sup.8 acrylic 88.2 89.93 45.04 31.5 101.96 51.07
35.71 resin Cem-FIL 020/2 P3 020/2 anhydrous P3.sup.9 EEA/SA 86.69
88.85 53.1 32.7 102.49 61.25 37.72 resin Cem-FIL 020/2 V38 020/2
anhydrous V38 PVC 84.28 89.17 63.47 54.2 105.80 75.31 64.31 resin
plastisol Cem-FIL 5197 K29 5197 aqueous K29 acrylic 64.64 83.85 0
26 129.72 0.00 40.22 resin Cem-FIL 5197 P3 5197 aqueous P3 EEA/SA
66.06 73.09 0 26.4 110.64 0.00 39.96 resin Cem-FIL 020/1 A15
020/1.sup.10 anhydrous A15 PVA 73.93 47.61 64.40 resin E-glass K29
aqueous K29 acrylic 83.97 56 33.16 14.1 66.69 39.49 16.79 resin
E-glass P3 aqueous P3 EEA/SA 89.09 68.04 0 14.4 76.37 0.00 16.16
resin .sup.1A blend of an epoxy polymer, vinyl and amine coupling
agents and a non-ionic surfactant produced by Cem FIL
Reinforcements. .sup.2Produced by Cem FIL Reinforcements.
.sup.3Produced by Cem FIL Reinforcements. .sup.4A blend of an epoxy
polymer, vinyl and amine coupling agents and a non-ionic surfactant
produced by Cem FIL Reinforcements. .sup.5A blend of an epoxy
polymer, metacrylic and epoxy coupling agents and non-ionic and
cationic surfactants produced by Cem FIL Reinforcements.
.sup.6Produced by Cem FIL Reinforcements. .sup.7A blend of
anhydrous polymerized epoxy amine, vinyl and amine coupling agents
and a non-ionic surfactant produced by Cem FIL Reinforcements.
.sup.8Produced by Cem FIL Reinforcements. .sup.9Produced by Cem FIL
Reinforcements. .sup.10A blend of anhydrous polymerized acrylate
amine, metacrylic and epoxy coupling agents and a non-ionic
surfactant produced by Cem FIL Reinforcements.
[0068] In performing the 5% NaOH accelerated aging test, glass
fiber specimens were collected from good quality, undamaged fabric.
Specimens from both the machine and cross-machine direction were
tested, each specimen having a length of 330 mm and a width of 50
mm. The specimens were freely submerged in an alkali bath of 5%
NaOH (sodium hydroxide) in distilled water for 28 days, with the
bath being replaced after each test. Following conditioning in the
alkali bath, the specimens were washed with at least 1 liter of
distilled water at least ten times. Following the washing, the
fabric specimens were dried for seven days at room temperature.
Following drying, the fabric specimens were tested in tension at a
rate of 2 in/min using a 5 in. jaw span.
[0069] The TAT test was performed in accordance with the draft
European Standard (Copyright 1997, CEN Members) prepared by the
Technical Committee for the European Committee for Standardization
(CEN) and submitted to CEN members. Coated single end samples were
placed in a tri-alkali solution consisting of 1 g of NaOH, 0.5 g of
Ca(OH).sub.2, and 4 g of KOH in 1 liter of distilled water at
60.degree. C. After twenty-four hours, they were taken out and
rinsed in tap water until a pH of 9 was reached. The samples were
then placed in an acid solution of 0.5% HCL for one hour, taken out
and rinsed in tap water until a pH of 7 was reached. The samples
were then dried for one hour in a 60.degree. C. oven. Following
drying in the oven, the samples were allowed to dry at room
temperature for twenty-four hours and then tested in tension.
[0070] SIC tests evaluate the alkali-resistance of glass strand or
filaments in cement, by measuring the tensile strength of a strand
set in a block of cement mortar. Well-stretched strands are
installed in a metallic mold frame with the free ends coated with a
coating mixture to protect the parts of the fibers that will not be
in contact with the cement. After mixing the cement paste, having a
water-to-cement ratio of 1:0.43 and a cement-to-sand ratio of
1:0.34, the mold is filled with the cement paste and vibrated to
avoid formation of air bubbles near the strands. The cement is
allowed to set for one hour at room temperature, then for
twenty-three hours in cold water, after which the mold frame is
removed.
[0071] The samples containing the cement block and strands are
subsequently aged by soaking in water at 80.degree. C. for four
days. The samples are then immersed in cold water. The samples are
then tested for tensile strength using a dynamometer.
[0072] The results of the TAT, NaOH accelerated aging, and SIC
tests reveal that certain coated AR-glass fibers have improved
tensile performance over uncoated AR-glass and E-glass. The test
results also indicate that the combination of sizing and coating
affects the tensile performance. Anhydrous sizings outperform
aqueous sizings. Further, the results reveal that a sizing/coating
combination of Cem-FIL anhydrous sizing 020 with the Cem-FIL PVC
plastisol V38 coating provides the best tensile performance.
[0073] The reinforcement system 10 can be applied to an existing
structural support 20 in the following exemplary manner. An outside
surface 22 of the structural support 20 is wetted, preferably with
water. (Prior to wetting the outside surface of the structural
support, it is preferred that the surface be cleared of extraneous
matter and cleaned with a mild soap, if necessary.) A first layer
14c of inorganic matrix is then applied by trowelling or similar
coating technique to the wetted surface 22 of the structural
support 20. It should be understood that the matrix is in a wet or
uncured state when it is applied to the support 20. Preferably, the
thickness of the matrix layers ranges from 1/16 to 1/4 inch, and
more preferably the thickness is approximately 1/8 inch. If the
thickness is too large, the matrix may exhibit shrinkage
cracking.
[0074] Once the first layer 14c of inorganic matrix has been
applied, an alkali-resistant fibrous layer 12b is embedded into the
first layer 14c of the matrix. This may be performed by hand or by
any automated method. Generally, the fibrous layers will be
provided in roll form and will be cut from the roll to the desired
shape and length. The fibrous layers may be oriented in a variety
of ways both with respect to the orientation of the support
structure and with respect to the orientation of the other fibrous
layers employed in the reinforcement system. Varying the
orientation of the fibrous layers in these ways can improve the
strengthening and ductility characteristics of the reinforcement
system.
[0075] After embedding a fibrous layer 12b into the first layer 14c
of matrix, a second layer 14b of inorganic matrix is applied over
the fibrous layer 12b. Again, this layer preferably has a thickness
between 1/16 and 1/4 inch, and more preferably is approximately 1/8
inch. After each layer 14a-c of inorganic matrix is applied, the
matrix may be trowelled to provide a substantially smooth
surface.
[0076] As shown in the exemplary embodiment in FIGS. 1 and 2, after
the second layer 14b of inorganic matrix has been applied, a second
fibrous layer 12a may be embedded in the second layer 14b of matrix
and a third layer 14a of inorganic matrix applied on top of the
second fibrous layer 12a. If desired, a third fibrous layer may be
embedded in the third matrix layer 14a and a fourth layer of
inorganic matrix applied on top of the third fibrous layer.
Although it is preferred that the reinforcement system include
between 1 and 3 fibrous layers and between two and four inorganic
matrix layers, additional fibrous layers and inorganic layers may
be employed. The additional fibrous layers and layers of inorganic
matrix will be applied in the same manner as described above. Once
all the desired layers of the system have been applied, the system
may be allowed to dry or cure on its own or may be cured or set by
any known means.
[0077] It is preferred that the reinforcement system 10 be applied
to the surface 22 of the support structure 20 so that substantially
the entire surface is covered. However, in certain applications, it
may be beneficial to apply the reinforcement system only to those
portions of the support structure which are most likely to fail, or
experience the highest load in shear or bending, for example.
[0078] The reinforcement system increases the overall performance
of the structural supports by increasing the load to failure and by
increasing the deflection limits or ductility of the structural
support system. Unlike the conventional fiber-reinforced polymer
systems which may be toxic, difficult to handle, costly, subject to
delamination, and have poor fire resistance and water/air
permeability, the reinforcement system of the present invention is
easy to install, and has improved fire resistance and improved
bonding to concrete, concrete masonry units (CMU) and brick.
Additionally the reinforcement system is less likely to delaminate
from the structural support, allows the concrete or CMUs to breathe
due to similar air and water permeability, has a pleasant aesthetic
appearance (can be blended into the concrete finish) and is lower
in cost.
SPECIFIC EXAMPLES
[0079] This invention and its advantages are further described with
reference to the following specific examples. The examples are
merely intended to be illustrative and not to be construed as
limiting the scope of the invention. In the following examples the
method as described above was employed and tested on masonry wall
and triplet samples. Results were obtained which indicate
significantly improved seismic strengthening for the overall
support system.
Example 1
[0080] Referring to FIG. 3, a lightly reinforced sample CMU block
wall 100 (wall 1) was constructed from standard 8.times.8.times.16
in. CMUs 110. The CMUs were constructed of a type N mortar,
consisting of 1 part sand, 3 parts Type I Portland cement, 1 part
hydrated lime, and water in sufficient quantity to make the mortar
mix workable by the technician. The wall was ten courses high with
the top two and bottom two courses 16 in. wider than the central
six courses forming an "I" shape. All of the blocks in the top two
and bottom two courses were fully grouted to get better load
transfer from a load frame (see FIG. 4) during testing and increase
the probability of wall failure not occurring within the wide top
and bottom sections of the wall. A #4 steel reinforcing bar 120 was
placed in the cells surrounding the central pier. All blocks
containing steel reinforcing bars were fully grouted. Three-eighth
inch face shell mortar bedding was used on the CMU blocks with the
cross webs of units adjacent to grouted blocks fully bedded to
prevent grout from flowing into adjacent cells. Dur-o-wal joint
reinforcement 130 was placed in the bed joints between the top two
and bottom two courses.
[0081] The reinforcement system of the present invention in this
example was comprised of an alkali-resistant glass fibrous layer
comprising AR-glass manufactured by Saint Gobain Corp. of St.
Catherines, Ontario, Canada, under the trademark Cem-FIL.RTM.
having a sizing comprised of a blend of epoxy polymers, vinyl and
amine coupling agents, and non-ionic surfactants produced by Cem
FIL Reinforcements under the product label number 5197, and a
coating comprised of an acrylic, and a cementitious inorganic
matrix manufactured by Quickrete Companies of Atlanta, Ga. under
the trademark QuickWall.RTM.. The QuickWall.RTM. matrix was mixed
in an electric mortar mixer with water and an acrylic
fortifier.
[0082] The AR-glass fibrous layer was a coated bi-directional
fibrous layer comprising a warp knit weft inserted opened meshed
grid, with two rovings per inch in the weft direction and one
roving per inch in the warp direction (see FIG. 2), and having
polyester stitch yarns. The coating was comprised of an acrylic
applied to the fibrous layer in a wt % of approximately 25-28% DPU.
The rovings were approximately 1200 Tex. The AR-glass fibrous layer
was cut from a 30-inch wide roll to the corresponding dimensions of
the sample CMU block wall 100.
[0083] A first layer of QuickWall.RTM. matrix was trowelled onto
the sample wall at approximately 1/8 inch thick. A first AR-glass
fibrous layer was then pressed by hand into the wet matrix. The
first AR-glass fibrous layer was oriented so that the weft
direction of the fibrous layer having two rovings was aligned
horizontal to the bottom of the sample wall. Next a second layer of
matrix approximately 1/8 inch in thickness was applied by
trowelling. A second AR-glass fibrous layer was then embedded by
hand into the second layer of matrix. The second AR-glass fibrous
layer was oriented so that the weft direction of the fibrous layer
was aligned perpendicular to the bottom of the sample wall.
Finally, a third layer of matrix approximately 1/8 inch in
thickness was applied by trowelling onto the second fibrous layer
to form a relatively smooth surface.
[0084] Before conducting the testing described below, the wall
sample reinforced with the reinforcement system was allowed to cure
for 30 days.
[0085] The sample wall reinforced with the exemplary reinforcement
system of the present invention according to the exemplary method
of the present invention was tested for in-plane shearing at the
U.S. Army Engineer Research and Development Center, Construction
Engineering Research Laboratory. Referring to FIGS. 3-5, the wall
sample 100 with the reinforcement system 150 applied to it was set
in a load test frame 160 and clamped in place using bolted steel
tubing 162 over the upper and lower specimen ears 102 and steel
channels and rods 164 attached to the load frame 160 using eye
bolts 166. The load floor test frame 160 was comprised of a
post-tensioned reinforced concrete reaction strong wall and a steel
frame. A 110-kip hydraulic actuator (not shown) with a .+-.20 in.
stroke was attached to the strong wall to provide horizontal forces
(HF) to the sample wall 100 through a steel tube 170 bolted to the
upper concrete beam 168. Two 50-kip actuators (North and South)
(not shown) with a .+-.3 in. stroke were attached to the steel
frame and the horizontal steel tube 170 to provide axial (vertical)
load (FVS and FVN) to simulate dead load above the wall specimen.
The hydraulics for the actuator were computer-controlled.
[0086] The wall sample 100 was instrumented using two linear
variable differential transducers and eight linear deflection
(yo-yo) gages to monitor wall sample movements (D1-D10) (See FIG.
5). For the in-plane shear testing, the South actuator was set in
load control and the North in stroke control; an initial 27 kip
load was applied to each. The North actuator (applying force FVN)
that was under stroke control was also slaved to the stroke signal
of the South vertical actuator (applying force FVS). Loading in
this manner allowed the force in the vertical actuators to vary
with respect to each other while maintaining a constant 54 kip
total axial load, thus forcing the top concrete beam of the test
frame 160 to remain horizontal and parallel to the bottom concrete
beam of the test frame 160. This configuration put an in-plane
shear load in the wall sample. Cyclic horizontal forces (HF) were
applied to the wall sample using the horizontal actuator. Table 2
shows the input time (sec) and displacement (in.) that the wall was
subjected to during the test. Displacement forces were terminated
upon wall sample failure.
TABLE-US-00002 TABLE 2 Time Displacement (Sec) (in.) 0 0 12.5 0.02
25 0 37.5 -0.02 50 0 62.5 0.02 75 0 87.5 -0.02 100 0 112.5 0.04 125
0 137.5 -0.04 150 0 162.5 0.04 175 0 187.5 -0.04 200 0 212.5 0.06
225 0 237.5 -0.06 250 0 262.5 0.06 275 0 287.5 -0.06 300 0 312.5
0.08 325 0 337.5 -0.08 350 0 362.5 0.08 375 0 387.5 -0.08 400 0
412.5 0.1 425 0 437.5 -0.1 450 0 462.5 0.1 475 0 487.5 -0.1 500 0
512.5 0.2 525 0 537.5 -0.2 550 0 562.5 0.2 575 0 587.5 -0.2 600 0
612.5 0.3 625 0 637.5 -0.3 650 0 662.5 0.3 675 0 687.5 -0.3 700 0
712.5 0.4 725 0 737.5 -0.4 750 0 762.5 0.4 775 0 787.5 -0.4 800 0
812.5 0.6 825 0 837.5 -0.6 850 0 862.5 0.6 875 0 887.5 -0.6 900 0
912.5 0.8 925 0 937.5 -0.8 950 0 962.5 0.8 975 0 987.5 -0.8 1000 0
1012.5 1 1025 0 1037.5 -1 1050 0 1062.5 1 1075 0 1087.5 -1 1100 0
1112.5 1.2 1125 0 1137.5 -1.2 1150 0 1162.5 1.2
[0087] Referring to FIG. 6, during the course of the wall test for
wall 1, cracking of the reinforcement began during the 0.2 inch
horizontal displacement cycles at the lower corners (LS and LN) of
the sample and then began to propagate downward as a typical
concrete shear crack at around 45 degrees. At 0.6 and 0.8 inch
horizontal displacements, cracking began to appear intermittently
in the middle of the central pier starting the formation of an
X-crack. At 1.0 inch displacement, significantly more cracks
appeared diagonally from the upper north reentrant corner (UN)
downward. At the same time cracking began growing upward and at a
45-degree angle from that corner. Finally, at 1.2 inch
displacement, the reinforcement cracked from the upper north
reentrant corner (UN) diagonally across the entire sample to the
south reentrant corner (LS), and the back face of the pier CMU
blocks sheared off and fell to the floor ending the test.
[0088] FIG. 7 shows a backbone curve of load versus displacement
(at D4 and D7) for the wall 1 sample as well as the backbone curve
for the control sample. The control sample was a CMU wall as
described above without the application of the reinforcement
system.
Example 2
[0089] A second wall sample 200 (wall 2) having a reinforcement
system applied was tested using the same testing method as
described above with respect to wall sample 1. Wall 2 was made in
accordance with the materials and procedure described in Example 1
and the reinforcement system applied to wall 2 was made with the
materials described in Example 1. The only difference between
Examples 1 and 2 is with respect to the method of reinforcement
application. In applying the reinforcement system of wall 2, the
first glass fibrous layer was oriented so that the weft direction
of the fabric having two rovings was at a 45.degree. angle to the
bottom of the wall running from the top left corner (US) to the
bottom right corner (LN). The second glass fibrous layer was
oriented so that the weft direction of the fibrous layer was
aligned perpendicular to the bottom of the sample wall 200.
[0090] Referring to FIG. 8, the reinforcement of wall 2 began to
show cracking at 0.3 inch horizontal displacement in the same way
as wall 1. Cracks appeared at the lower reentrant corners (LS and
LN) and propagated downward, as is typical with concrete shear
crack growth. At 0.6 inch horizontal displacement, an X-crack began
to appear across the central pier section of the wall. Then at 0.8
inch displacement the reinforcement developed a horizontal crack
near the second pier bed joint. The back face of the CMU blocks
sheared off and the wall began to buckle ending the test.
[0091] FIG. 9 shows a backbone curve of load versus displacement
(at D4 and D7) for the wall 2 sample as well as the backbone curve
for the control sample. Again, the control sample was a CMU wall
without the application of the reinforcement system.
Example 3
[0092] A third wall sample 300 (wall 3) having a reinforcement
system applied was tested using the same testing method as
described above with respect to wall samples 1 and 2. Wall 3 was
made in accordance with the materials and procedure described in
Example 1. The reinforcement system applied to wall 3 was made with
the material compositions described in Example 1, except that the
final layer of matrix applied to the reinforcement was comprised of
QuickWall Sanded.RTM. material from QuickCrete having more sand
than the regular QuickWall.RTM. product.
[0093] The reinforcement system applied to wall 3 included a third
glass fibrous layer embedded in the third layer of matrix and a
fourth layer of matrix (the QuickWall Sanded.RTM. material) applied
as the top coat. In applying the reinforcement system of wall 3,
the first glass fibrous layer was oriented so that the weft
direction of the fabric having two rovings was at a 45.degree.
angle to the bottom of the wall running from the top left corner
(US) to the bottom right corner (LN). The second glass fibrous
layer was oriented so that the weft direction of the fibrous layer
was at a 45.degree. angle to the bottom of the wall running from
the top right (UN) to the bottom left corner (LS). The third glass
fibrous layer was oriented so that the weft direction of the
fibrous layer was aligned perpendicular to the bottom of wall
3.
[0094] Referring to FIG. 10, cracking in the reinforcement
initiated at 0.2 inch horizontal deflection in the lower north
reentrant corner (LN). From 0.3 inch to 1.0 inch displacement, the
crack grew along the bed joint at that location to a length of 7
inches. At 0.4 inch horizontal displacement a crack began in the
other lower reentrant corner (LS), angling downward. It continued
on the next amplitude of horizontal displacement. At 0.8 inch
displacement, a new crack started there and followed the bed joint
approximately 8 inches. A diagonal crack along the same line as the
wall 1 failure initiated at 0.5 inch horizontal displacement and
grew during the 0.8 displacement cycles. At 0.8 inch displacement,
a crack initiated in the upper north reentrant corner (UN) angling
upward. Then at 1.0 inch horizontal displacement, several more
cracks initiated at that corner and all grew upward at varying
angles. During the 1.0 inch horizontal displacement cycles the CMU
blocks began to shear, and since the wall was in imminent danger of
collapse, the test was halted. Examination of the ends and rear of
the wall revealed that the back face had a well-developed X-crack
and the front face was beginning to shear off just behind the
reinforcement. The reinforcement did not fail during this test.
[0095] FIG. 11 shows a backbone curve of load versus displacement
(at D4 and D7) for the wall 3 sample as well as the backbone curve
for the control sample. Again, the control sample was a CMU wall
without the application of the reinforcement system.
Example 4
[0096] Referring to FIG. 12, three triplet samples 400 were
constructed using standard 8.times.8.times.16 inch CMUs. The
triplet samples 400 were constructed from three blocks 402, 404 and
406, placed in a stack-bond with the center block 404 offset by 3/4
inch. The reinforcement system 410 applied to the three triplet
samples was made with the material compositions described in the
above Examples, except that the matrix layers were comprised of
QuickWall.RTM. Sanded material as opposed to the regular
QuickWall.RTM. product.
[0097] The application process of the reinforcement system for the
three triplet samples 400 was identical to the application process
for the three wall samples described above. The first triplet
sample (triplet 1) received two glass fibrous layers. The first
glass fibrous layer of the first triplet was oriented so that the
weft direction of the fibrous layer having two rovings was aligned
horizontal to the bottom of the triplet standing on end (as shown
in FIG. 2). The second glass fibrous layer was oriented so that the
weft direction of the fibrous layer was aligned perpendicular to
the bottom of the triplet. The second triplet sample (triplet 2)
also received two glass fibrous layers. The first glass fibrous
layer of the second sample was oriented so that the weft direction
of the fabric was at a 45.degree. angle to the bottom of the
triplet running from the top left corner to the bottom right
corner. The second glass fibrous layer was oriented so that the
weft direction of the fibrous layer was aligned perpendicular to
the bottom of the triplet sample. The third triplet sample (triplet
3) received three glass fibrous layers. The first glass fibrous
layer of the third triplet sample was oriented so that the weft
direction of the fabric was at a 45.degree. angle to the bottom of
the triplet running from the top left corner to the bottom right
corner. The second glass fibrous layer was oriented so that the
weft direction of the fibrous layer was at a 45.degree. angle to
the bottom of the triplet running from the top right to the bottom
left corner. The third glass fibrous layer was oriented so that the
weft direction of the fibrous layer was aligned perpendicular to
the bottom of the triplet. As with the wall samples, the triplets
were allowed to cure for thirty days before testing.
[0098] The triplets 400 were tested in a million-pound test frame.
The samples were placed on the load platen of the test frame so
that the center, offset block was up. Steel plates were bolted to
the ends of the triplet samples and tightened to apply a 4800-pound
clamping force on the triplets. This force corresponds to the
150-psi axial load applied to the wall samples. The triplets were
then loaded in compression at a constant load rate of 0.0027
in./sec. Table 3 lists the maximum loads for each of the triplet
samples.
TABLE-US-00003 TABLE 3 MAXIMUM LOADS FOR TRIPLET TESTS Triplet ID
Maximum Load (lb) 1 43,175 2 47,350 3 48,031
[0099] Since the reinforcement system was applied to only one face
of the triplet samples, there was less resistance to the load on
the face with no reinforcement applied. This resulted in a shearing
of the rear face shell and compression of the center face on the
back to a point level with the adjoining block faces. In all
instances, the face with the reinforcement applied resisted the
compression. FIG. 13 is a plot of load versus crosshead
displacement for the triplet test
[0100] Triplet 1 had the least damage to the reinforcement system.
There were a few hairline cracks approximately 1 inch long
distributed along the mortar joints at about a 30 degree angle from
the horizontal.
[0101] Triplet 2 showed the most damaged to the reinforcement.
Cracks developed at the reentrant corners on the triplet. A large
one developed at the bottom and smaller ones developed at the top.
Examination of the reinforcement revealed initiation of some
delamination. After removing the triplet from the test machine, the
CMU face of the center block was pulled free of the reinforcement,
which remained intact.
[0102] Triplet 3 yielded small hairline cracks at the top reentrant
corners of the reinforcement, which was the only visible damage to
the reinforcement side of the specimen.
RESULTS
[0103] The benefit of applying the AR-glass fabric reinforced
inorganic matrix to support structures such as the walls described
above is to add strength to the support structure and to improve
structure performance by increasing deflection limits. These
benefits result in improved earthquake and explosion resistance.
The backbone curves, as shown in FIGS. 7, 9, and 11 indicate the
engineering strength of the support structure under consideration.
The engineering strength is defined as the peak load transcribed by
the back bone curve. For engineering purposes, the engineering
strength is a better indicator of the system performance than the
measured peak load because it incorporates a factor of safety that
may or may not be present when considering the peak load value.
[0104] For each reinforced wall sample tested, the engineering load
improved over a control sample having no reinforcement. Wall 1,
exhibiting a 57% strength increase over the control, performed the
best, followed by Wall 3 having a 42% increase and Wall 2 having a
38% increase. FIG. 14 illustrates different configurations of
fiber-reinforced-polymer (FRP) reinforcement systems applied to
wall samples tested in prior tests at the U.S. Army Engineer
Research and Development Center, Construction Engineering Research
Laboratory under similar conditions. The FRP reinforced samples
were loaded in in-plane shear with 54 kips axial load applied to
them. FIG. 15 compares the engineering load increases for sample
Walls 1-3 to sample walls having FRP reinforcement systems applied
in the different configurations shown in FIG. 14, over the control
sample having no reinforcement.
[0105] The maximum horizontal load each wall resisted, along with
the engineering load and their comparisons to the control walls are
listed in Table 4. The order of maximum horizontal load resistance
for each wall is the same as the engineering load order. In
addition to providing the maximum strength increase, Wall 1 also
exhibited the best displacement prior to failure. FIG. 16 compares
the wall displacements with each other and also to FRP reinforced
wall samples tested in prior tests. Table 5 lists the maximum
displacement between gages D7 and D4 (See FIG. 5) for Walls 1-3,
and compares those values to the with the control having no
reinforcement applied. The walls tested showed improvements ranging
from 29% for Wall 2 to 44% for Wall 1.
TABLE-US-00004 TABLE 4 WALL LOAD COMPARISONS SHOWING MAXIMUM
ENGINEERING LOAD Max Load (L) (EL) .DELTA..sub.L .DELTA..sub.EL
.DELTA..sub.L .DELTA..sub.EL Wall No. (kips) (kips) (kips) (kips)
(%) (%) 1 55.7 53.28 17.68 19.37 46.50 57.12 2 49.96 46.81 11.94
12.9 31.40 38.04 3 53.25 48.26 15.23 14.35 40.06 42.32 Control
38.02 33.91
TABLE-US-00005 TABLE 5 WALL DISPLACEMENT COMPARISONS SHOWING
MAXIMUM DISPLACEMENT Max Displacement .DELTA..sub.S .DELTA..sub.S
Wall No. (inches) (inches) (%) 1 1.224 0.876 43.97 2 0.577 0.229
29.13 3 0.631 0.283 37.64 Control 0.348
[0106] To summarize the results of the testing of Wall Samples 1-3,
the AR-glass reinforced inorganic matrix reinforcing system of the
present system added 47-53 kips of horizontal resistance, or
38%-57% to the engineering strength of the wall samples in in-plane
shear. The material added 0.58-1.22 inches of horizontal
displacement, or 29%-44% to the wall samples in in-plane shear.
Wall 1, having two fibrous layers of fabric applied at 0.degree.
and 90.degree. to each other and the wall performed better than the
other configurations. Three glass fibrous layers, two aligned at
.+-.45.degree. and the third at 0.degree. and 90.degree. to the
wall sample, performed better than two glass fibrous layers aligned
at 0.degree. and 90.degree. to each other but .+-.45.degree. to the
wall sample. All wall failures were due to shear between the front
and rear faces of the blocks. There were no delaminations of the
reinforcement system of Walls 1-3 from the CMU walls.
* * * * *