U.S. patent application number 12/325611 was filed with the patent office on 2009-08-13 for method of constructing an insulated shallow pier foundation building.
This patent application is currently assigned to NOVA CHEMICALS INC.. Invention is credited to Ginawati Au, Jeffrey Beaman, Frank Kovatch, Bret McLean, Leslie Molke, Justin Rubb, Robert Stoffa.
Application Number | 20090202307 12/325611 |
Document ID | / |
Family ID | 40939002 |
Filed Date | 2009-08-13 |
United States Patent
Application |
20090202307 |
Kind Code |
A1 |
Au; Ginawati ; et
al. |
August 13, 2009 |
METHOD OF CONSTRUCTING AN INSULATED SHALLOW PIER FOUNDATION
BUILDING
Abstract
A method of constructing a shallow pier foundation building that
includes a) placing a plurality of insulating pier forms along a
perimeter of the building; b) placing a plurality of insulating
concrete forms between the insulating piers to form a continuous
insulating surface to the surrounding soil and a continuous forming
surface to provide a slab form; c) placing a concrete composition
in the insulating piers and insulating concrete forms and allowing
the concrete composition to cure and harden; and d) placing a
concrete slab composition in the slab form and allowing the
concrete composition to cure and harden.
Inventors: |
Au; Ginawati; (Aliquippa,
PA) ; McLean; Bret; (Cortland, OH) ; Molke;
Leslie; (Copley, OH) ; Kovatch; Frank;
(Pittsburgh, PA) ; Beaman; Jeffrey; (Monaca,
PA) ; Stoffa; Robert; (Cranberry Township, PA)
; Rubb; Justin; (Coraopolis, PA) |
Correspondence
Address: |
NOVA Chemicals Inc.
Westpointe Center, 1550 Coraopolis Heights Road
Moon Township
PA
15108
US
|
Assignee: |
NOVA CHEMICALS INC.
Moon Township
PA
|
Family ID: |
40939002 |
Appl. No.: |
12/325611 |
Filed: |
December 1, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61027532 |
Feb 11, 2008 |
|
|
|
61074173 |
Jun 20, 2008 |
|
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Current U.S.
Class: |
405/233 |
Current CPC
Class: |
E02D 27/02 20130101 |
Class at
Publication: |
405/233 |
International
Class: |
E02D 5/00 20060101
E02D005/00 |
Claims
1. A method of constructing a shallow pier foundation building
comprising: a) placing a plurality of insulating pier forms along a
perimeter of the building; b) placing a plurality of insulating
concrete forms between the insulating piers to form a continuous
insulating surface to the surrounding soil and a continuous forming
surface to provide a slab form; c) placing a concrete composition
in the insulating piers and insulating concrete forms and allowing
the concrete composition to cure and harden; and d) placing a
concrete slab composition in the slab form and allowing the
concrete composition to cure and harden.
2. The method according to claim 1, wherein the insulating pier
form comprises (A) a first panel member comprising a first end and
a second end: (B) a second panel member comprising a first end and
a second end, wherein the first end is connected to the second end
of the first panel; (C) a third panel member comprising a first end
and a second end, wherein the first end is connected to the second
end of the second panel; and (D) a fourth panel member comprising a
first end and a second end, wherein the first end is connected to
the second end of the third panel and the second end is connected
to the first end of the first panel; wherein the first, second,
third and forth panels maintain a spatial distance therebetween for
defining a molding chamber generally having a rectangular cross
section.
3. The method according to claim 1, wherein the insulating concrete
form comprises (A) a first panel member comprising: (1) a first
outer panel side including a first wall surface area extending
generally vertically thereon; (2) a first inner panel side
positioned oppositely from said first outer panel side; and (3) at
least two first slots in the first inner panel side adapted to
accept a connecting member; (B) a second panel member comprising:
(1) a second outer panel side including a second wall surface area
extending generally vertically thereon and facing oppositely from
said first panel member; (2) a second inner panel side positioned
oppositely from said second outer panel side and facing said first
inner panel side of said first panel member; and (3) at least two
second slots in the second inner panel side adapted to accept a
connecting member; and (C) at least two connecting members
detachable and securable with respect to said first panel member
and said second panel member adapted to maintain a spatial distance
therebetween for defining a molding chamber therebetween, the
connecting members comprising: (1) a first flange detachably and
securably extending within said first slot of said first panel
member; (2) a second flange detachably and securably extending
within said second slot of said second panel member; and (3) a
mid-section portion.
4. The method according to claim 1, wherein the insulating pier
form and the insulating concrete form comprise an expanded polymer
matrix.
5. The method according to claim 4, wherein the expanded polymer
matrix comprises one or more polymers selected from the group
consisting of homopolymers of vinyl aromatic monomers; copolymers
of at least one vinyl aromatic monomer with one or more of
divinylbenzene, conjugated dienes, alkyl methacrylates, alkyl
acrylates, acrylonitrile, and/or maleic anhydride; polyolefins;
polycarbonates; an interpolymer of a polyolefin and in situ
polymerized vinyl aromatic monomers; and combinations thereof.
6. The method according to claim 4, wherein the polymer matrix
comprises carbon black, graphite or a combination thereof.
7. The method according to claim 3, wherein the first panel member
and the second panel member each have a male end comprising a
tongue edge and a female end comprising a female groove edge that
facilitates a tongue and groove union between corresponding
members.
8. The method according to claim 3, wherein the connecting member
comprises a material selected from the group consisting of
plastics, metal, construction grade plastics, composite materials,
ceramics, and the like.
9. The method according to claim 1, wherein the concrete comprises
one or more cements selected from the group consisting of Portland
cements, pozzolana cements, gypsum cements, aluminous cements,
magnesia cements, silica cements, and slag cements.
10. The method according to claim 1, wherein the concrete is light
weight concrete.
11. The method according to claim 9, wherein the concrete comprises
8-20 volume percent cement, 11-50 volume percent sand, 10-31 volume
percent expanded thermoplastic particles, 9-40 volume percent
coarse aggregate, and 10-22 volume percent water; wherein the
expanded thermoplastic particles have an average particle diameter
of from 0.2 mm to 8 mm, a bulk density of from 0.02 g/cc to 0.64
g/cc, an aspect ratio of from 1 to 3.
12. The method according to claim 2, wherein rebar is placed in the
molding chamber prior to placing the concrete.
13. The method according to claim 3, wherein rebar is placed in the
molding chamber prior to placing the concrete.
14. The method according to claim 11, wherein the expanded
thermoplastic particles comprise polymers containing polymerized
residues from one or more monomers selected from the group
consisting of styrene, ethylene, propylene, and
methyl(meth)acrylate; an interpolymer of a polyolefin and in situ
polymerized vinyl aromatic monomers; and combinations thereof.
15. The method according to claim 1, wherein a water impervious
fabric is placed over the outward facing continuous insulating
surface.
16. The method according to claim 15, wherein a top edge of the
water impervious fabric is above grade.
17. A building constructed according to the method of claim 1.
Description
REFERENCE TO RELATED APPLICATION
[0001] The present nonprovisional patent application is entitled to
and claims the right of priority under 35 U.S.C. .sctn.119(e) of
U.S. Provisional Patent Application Ser. Nos. 61/027,532, filed
Feb. 11, 2008 and 61/074,173, filed Jun. 20, 2008, which are hereby
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is directed to systems, methods and
articles for constructing a shallow pier foundation building and in
particular, to such systems and methods that utilize wall forming
systems and/or insulating concrete walls to construct
structures.
[0004] 2. Description of the Prior Art
[0005] In home and building construction, exterior grade beams, or
footings, are often utilized which are formed in ditches, or the
like, to support the exterior walls of the building. These concrete
grade beams are often poured in conjunction with a continuous slab,
which extends in the area between the grade beams and can be poured
simultaneously with, or separate from, the grade beams.
[0006] However, problems are encountered in connection with these
types of arrangements, especially when the building site contains
soil of varying compactness and plasticity. For example, in cases
when a building site is extensively graded to level it and soil is
moved from one portion of the lot to the other, the soil
immediately underneath the removed soil is relatively compact while
the soil that is moved to other portions of the building site is
relatively loose. This, of course, causes differential movements of
the foundation and the grade beams and potential problems with
regard to cracking, breaking, or the like.
[0007] In northern latitudes, such as, for example, in Canada,
northern Europe and the northern portions of the United States,
soils, and particularly fine grained water saturated soils, are
susceptible to the formation of ice lenses and frost heave. These
phenomena can greatly diminish the stability and integrity of
structures embedded in such soils. In many cases, footings are
placed at a depth of not less than the depth of normal frost
penetration. This prevents damage to the footing from the swelling
and shrinkage of the surrounding soil caused by freeze-thaw cycles
or displacement from frost heaving. However, while placing the
footing below the depth of frost penetration may protect the
footing from the effects of frost action, the pier that transfers
the loads from the supported structure to the footing remains above
the frost line and therefore remains vulnerable to frost and ice
action.
[0008] The mechanisms of frost heave and frost action are well
known to persons skilled in the art. The main phenomenon of concern
to the construction industry is the displacement, laterally and
vertically, of foundation members due to loads placed upon them
from frost action. Where surrounding soil is frozen to a pier
connecting a supported structure to a supporting footing, movement
of the soil frozen to the pier will displace the pier. This will
diminish the stability of the footing and structure to which it is
attached no matter the depth of the footing below the frost line.
In northern climates, a pier must be of a significant length to
connect a footing placed below the frost line to the structure on
the surface. Most of the entire length of the pier embedded in
frost susceptible soil will be vulnerable to frost action.
[0009] Several techniques have been suggested to combat these
problems. For example, a concrete pier system has been suggested in
which relatively deep holes are formed and concrete poured into the
holes to form a pier for the exterior grade beam. However, these
concrete piers have several disadvantages. For example, the depth
to which the beam is formed is often based on a single soil test at
one area, which is not necessarily representative of the entire
area. Thus the pier, although adequate in height for the particular
area tested, may be insufficient to adequately support the
foundation in other areas having a softer or more plastic soil
composition.
[0010] Also, the drills used to drill the pier holes do not
necessarily clean out the bottom of the holes which causes
difficulty in the stability of the beam once it has been poured.
Further, the pier drill may encounter soft rock strata or the like
which jams the drill and causes undue delays. Still further,
upheaval forces, i.e., forces in the upward direction often occur
due to the changes in the wetness or the dryness of the soil, which
causes a poured concrete pier to fail. Still further, in soils
having a large percentage of clay there is a certain practical
limit on the height of the pier, which does not necessarily support
the foundation adequately in this type of environment.
[0011] Other techniques for constructing an adequate exterior grade
beam support include a post tension technique in which cables are
passed through the forms for the grade beams and, after the
concrete is poured thereover, are placed in very high tensile
stress to increase the resistance of the foundation to cracking or
failing. However, these types of techniques require a great deal of
labor and are also subject to fail.
[0012] As indicated above, the above-described problems can be
exacerbated when freeze thaw cycles are introduced. If the piers
are not placed and spaced properly with adequate depth, upward
forces that can cause heaving are generated during freezing
conditions followed by downward forces during thawing conditions.
The resulting heaving and relaxation can lead to cracks and
eventual failure of a slab and pier foundation system.
[0013] U.S. Pat. No. 4,125,975 discloses a foundation on grade
support for manufactured housing that attempts to minimize vertical
or lateral shifting of the home, due to earth movements resulting
from mud or freeze-thaw induced shifting of the supporting soil.
The foundation arrangement includes a plurality of telescoping
stanchions which are adapted to be raised in order to be connected
to the underframe and lowered to a final position.
[0014] U.S. Pat. No. 4,754,588 discloses a foundation piling system
in which pilings are used to support a foundation system in soil
having a varied composition and moisture content. The pilings
extend into concrete grade beams forming a portion of a monolithic
system including a concrete slab. Flanges extend from the end
portions of the pilings that are disposed in the grade beam and a
plurality of horizontally extending reinforcing bars extend through
openings in the flanges.
[0015] U.S. Pat. No. 6,318,700 discloses a mold for a conical
concrete pier for use in constructing buildings in frost-prone
northern climates.
[0016] U.S. Patent Application Publication 2006/0257210 discloses a
residential flooring system for use with expansive soil. The system
includes a plurality of pre-cast slabs of hardened concrete with
structural members such as rebar and/or wire mesh. The system also
includes structural drilled pier members that contact the expansive
soil and extend upward away from the expansive soil. The pier
members have an upper contact surface that extends above the soil.
Weight bearing members are attached to the structural members and
include a bearing surface that is larger (e.g., has a greater area)
than the upper contact surface of the pier or other structural
member. The pre-cast slabs are positioned on the weight bearing
surfaces so that the slabs are supported by the structural members
via the weight bearing members.
[0017] U.S. Pat. No. 6,964,139 discloses a column for use in
post-frame construction having a two piece construction in which a
first or foundation column portion of the column is set into the
earth with a proximal end thereof protruding from the earth. The
proximal end of the foundation column includes a column bracket for
joining the foundation column to a wooden column comprising the
second portion of the two piece column. The foundation column of
the present invention includes a precast concrete column.
[0018] U.S. Patent Application Publication 2008/0016805 discloses
panelized building systems that include pre-manufactured floor and
stem wall panels that can be built according to site-specific
requirements. The floor panels can include height-adjustable
members to raise/lower portions of one or more panels to a desired
height relative to an underlying surface. The floor panels can be
leveled, locked together, and then remaining portions of a building
structure can be built around the floor panels in a top-down
process. The height-adjustable members can include a pier and jack
system that includes a jack screw, a sleeve, and a pier.
[0019] The systems described above and those presently known and in
use do not provide adequate resistance to frost heave in general or
to vertical and lateral movements of the soil, occurring as a
result of mud, frost, thawing, etc. in particular. These
deficiencies indicate a clear and present need in the art for
systems, methods and structures that provide more secure support in
an arrangement and/or system for pier and floating slab
foundations, which minimize and/or eliminate the deficiencies
described above.
SUMMARY OF THE INVENTION
[0020] The present invention provides a method of constructing a
shallow pier foundation building that includes a) placing a
plurality of insulating pier forms along a perimeter of the
building; b) placing a plurality of insulating concrete forms
between the insulating piers to form a continuous insulating
surface to the surrounding soil and a continuous forming surface to
provide a slab form; c) placing a concrete composition in the
insulating piers and insulating concrete forms and allowing the
concrete composition to cure and harden; and d) placing a concrete
slab composition in the slab form and allowing the concrete
composition to cure and harden.
DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective view of an insulating pier form that
can be used according to the invention;
[0022] FIG. 2 is a top plan view of an insulating pier form that
can be used according to the invention;
[0023] FIG. 3 is a perspective view of a partially constructed
insulating pier form that can be used according to the
invention;
[0024] FIG. 4 is a top plan view of a corner connection of an
insulating pier form that can be used according to the
invention;
[0025] FIG. 5 is a perspective view of an insulating concrete form
that can be used according to the invention;
[0026] FIG. 6 is a perspective view of an insulating concrete form
that can be used according to the invention;
[0027] FIG. 7 is a top plan view of an insulating concrete form
that can be used according to the invention;
[0028] FIG. 8 is a front elevation view of a connecting member that
can be used with the insulating concrete forms according to the
invention;
[0029] FIG. 9 is a top plan view of a connecting member that can be
used with the insulating concrete forms according to the
invention;
[0030] FIG. 10 is a front elevation view of a connecting member
that can be used with the insulating concrete forms according to
the invention;
[0031] FIG. 11 is a perspective view of an insulating concrete
footer form panel that can be used according to the invention;
[0032] FIG. 12 is a perspective view of an insulating concrete
footer form panel that can be used according to the invention;
[0033] FIG. 13 is a plan view of an arrangement of insulating pier
forms and insulating concrete forms according to embodiments of the
invention;
[0034] FIG. 14 is a cross-section elevation view of a corner
concrete pier and floating concrete slab according to embodiments
of the invention;
[0035] FIG. 15 is a cross-section elevation view of an insulating
concrete wall and floating concrete slab according to embodiments
of the invention; and
[0036] FIG. 16 is a cross section elevation view of a portion of a
frost wall according to embodiments of the invention; and
[0037] FIG. 17 is a cross section elevation view of a portion of a
frost wall according to embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0038] For the purpose of the description hereinafter, the terms
"upper", "lower", "inner", "outer", "right", "left", "vertical",
"horizontal", "top", "bottom" and derivatives thereof, shall relate
to the invention as oriented in the drawing Figures. However, it is
to be understood that the invention may assume alternate variations
and step sequences except where expressly specified to the
contrary. It is also to be understood that the specific devices and
processes, illustrated in the attached drawings and described in
the following specification, is an exemplary embodiment of the
present invention. Hence, specific dimensions and other physical
characteristics related to the embodiment disclosed herein are not
to be considered as limiting the invention. In describing the
embodiments of the present invention, reference will be made herein
to the drawings in which like numerals refer to like features of
the invention.
[0039] Other than where otherwise indicated, all numbers or
expressions referring to quantities, distances, or measurements,
etc. used in the specification and claims are to be understood as
modified in all instances by the term "about". Accordingly, unless
indicated to the contrary, the numerical parameters set forth in
the following specification and attached claims are approximations
that can vary depending upon the desired properties, which the
present invention desires to obtain. At the very least, and not as
an attempt to limit the application of the doctrine of equivalents
to the scope of the claims, each numerical parameter should at
least be construed in light of the number of reported significant
digits and by applying ordinary rounding techniques.
[0040] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical values, however,
inherently contain certain errors necessarily resulting from the
standard deviation found in their respective measurement
methods.
[0041] Also, it should be understood that any numerical range
recited herein is intended to include all sub-ranges subsumed
therein. For example, a range of "1 to 10" is intended to include
all sub-ranges between and including the recited minimum value of 1
and the recited maximum value of 10; that is, having a minimum
value equal to or greater than 1 and a maximum value of equal to or
less than 10. Because the disclosed numerical ranges are
continuous, they include every value between the minimum and
maximum values. Unless expressly indicated otherwise, the various
numerical ranges specified in this application are
approximations.
[0042] As used herein, the term "expandable polymer matrix" refers
to a polymeric material in particulate or bead form that is
impregnated with a blowing agent such that when the particulates
and/or beads are placed in a mold and heat is applied thereto,
evaporation of the blowing agent (as described below) effects the
formation of a cellular structure and/or an expanding cellular
structure in the particulates and/or beads and the outer surfaces
of the particulates and/or beads fuse together to form a continuous
mass of polymeric material conforming to the shape of the mold.
[0043] As used herein, the term "polymer" is meant to encompass,
without limitation, homopolymers, copolymers and graft
copolymers.
[0044] As used herein, the terms "(meth)acrylic" and
"(meth)acrylate" are meant to include both acrylic and methacrylic
acid derivatives, such as the corresponding alkyl esters often
referred to as acrylates and (meth)acrylates, which the term
"(meth)acrylate" is meant to encompass.
[0045] As used herein, the term "floating slab" refers to a
structural engineering practice whereby a concrete slab, that is to
serve as the bottom floor of a structure, is formed by setting a
mold into the ground and pouring concrete into the mold, leaving no
space between the ground and the structure.
[0046] As used herein, the terms "insulating concrete form" or
"ICF" refer to stay-in-place formwork for cast-in-place
reinforced-concrete walls. A typical ICF includes interlocking
modular units that can be dry-stacked and filled with concrete.
[0047] As used herein, the term "reinforced concrete" refers to
concrete into which reinforcement bars ("rebar") or fibers have
been cast to carry tensile loads in order to strengthen a structure
that would otherwise be brittle.
[0048] As used herein, the term "concrete pier" refers to a
cast-in-place reinforced-concrete structure typically constructed
with a stay-in-place, single-use form having a first end below
ground level and a second end protruding at or above ground
level.
[0049] The present invention is directed to shallow pier foundation
structures, pier and floating slab structures, and to methods of
constructing such structures.
[0050] Embodiments of the invention provide methods of constructing
a shallow pier foundation structure or building that includes
placing a combination of insulating pier forms and insulating
concrete forms along a planned perimeter of the structure or
building, placing a concrete composition in the insulating piers
and insulating concrete forms, and placing a concrete slab in the
space defined by the insulating pier forms and insulating concrete
forms.
[0051] In an exemplary embodiment of the invention shown in FIGS. 1
and 2, insulating pier form 10 includes footer portion 12 and post
portion 14. Post portion 14 includes first panel member 16 having
first end 18 and second end 20; second panel member 22 having first
end 24 and second end 26, where first end 24 is connected to second
end 20 of first panel 16 by way of connector 28; third panel member
30 having first end 32 and second end 34, where first end 32 is
connected to second end 26 of second panel 22 by way of connector
36; and fourth panel member 38 having first end 40 and second end
42, where first end 40 is connected to second end 34 of third panel
30 by way of connector 44 and second end 42 is connected to first
end 18 of first panel 16 by way of connector 46.
[0052] Footer portion 12 includes first panel member 50 having
first end 52 and second end 54; second panel member 56 having first
end 58 and second end 60, where first end 58 is connected to second
end 54 of first panel 50 by way of connector 62; third panel member
64 having first end 66 and a second end 68, where first end 66 is
connected to second end 60 of second panel 56 by way of connector
70; and fourth panel member 72 having first end 74 and second end
76, where first end 74 is connected to second end 68 of third panel
64 by way of connector 78 and second end 76 is connected to first
end 52 of first panel 50 by way of connector 80.
[0053] A bottom surface of panel 22 is attached to first post
support 82. First end 84 of post support 82 is attached to a top
surface of panel 50 and a second end 86 of post support 82 is
attached to a top surface of panel 64. A bottom surface of panel 38
is attached to second post support 88. First end 90 of post support
88 is attached to a top surface of panel 50 and a second end 90 of
post support 88 is attached to a top surface of panel 64.
[0054] In embodiments of the invention, water impervious fabric 85
is placed over the portion of the outward facing surface of
insulating pier form 10. As used herein, "outward facing surface"
refers to the portion of the surface of a form that will be exposed
to the earth and weather outside of the planned building.
Typically, top edge 87 of water impervious fabric 85 will extend
above grade when the building is completed.
[0055] Typically, water impervious fabric 85 is a layered fabric
that includes channels, capillaries, and/or dimples that provide
for seepage and/or drainage of moisture. The materials of
construction for water impervious fabric 85 are typically pressure
resistant, rot-proof, and resistant to saline solutions, inorganic
acids, alkalis, and liquids such as alcohols, organic acids,
esters, ketones, and similar substances and are typically not
damaged or affected by minerals, humic acid, or bacterial
decomposition in the earth and is resistant to bacteria, fungi
and/or microorganism. In many embodiments, water impervious fabric
85 is constructed using thermoplastics, non-limiting examples of
which include polyethylene and polypropylene.
[0056] In embodiments of the invention, shown in FIGS. 3 and 4,
post portion 14 can be constructed by combining connecting panels
94 using connecting braces 95 and connectors 28, 36, 44 and 46. As
a non-limiting example, connector 28 includes a first receiving
space defined by end plate 96, first flange 97 and common base 98
and a second receiving space defined by end plate 96, second flange
99 and common base 98. In this embodiment, end 24 fits securely
into the first receiving space and end 20 fits securely into the
second receiving space connecting first panel 16 to second panel
22.
[0057] As shown in FIG. 3, a plurality of connecting panels 94 can
be used to provide the height, surfaces and form of post portion
14. A top surface of connecting panels 94 includes a plurality of
slots 93, which are adapted to receive bottom portion 89 of
connectors 95. A similar plurality of slots (not shown) are
included along a bottom surface of connecting panels 94 and are
adapted to receive top portion 91 of connectors 95.
[0058] When used according to the present invention, rebar is
typically placed in footer portion 12 and post portion 14 prior to
placing concrete into insulating pier form 10. In many cases, the
rebar can extend from insulating pier form 10 to other insulating
pier forms and/or adjacent insulating concrete forms.
[0059] Various insulating concrete forms can be used in the
structures and methods of the present invention. As non-limiting
examples, the insulating concrete forms disclosed in U.S. Pat. Nos.
5,333,429; 5,390,459; 5,566,518; 5,568,710; 5,657,600; 5,709,060;
5,787,665; 5,822,940; 5,845,449; 5,887,401; 6,098,367; 6,167,624;
6,170,220; 6,235,367; 6,314,697; 6,318,040; 6,336,301; 6,363,683;
6,438,918; 6,526,713; 6,588,168; 6,647,686 and 6,820,384; U.S.
Patent Application Publication Nos. 2002/0116889 and 2003/0005659;
and copending U.S. Publication Application Nos. 2006/0251851;
2008/0066408; 2008/0104911; 2008/0104912; and 2008/0107852; the
relevant portions of which are incorporated herein by reference.
Commercially available insulating concrete forms that can be used
include, but are not limited to those available under the
tradenames GREENBLOCK.RTM. available from Greenblock Worldwide
Corp, Stuart, Fla.; ECO-Block available from ECO-Block, LLC,
Dallas, Tex.; and QUAD-LOCK.RTM. available from Quad-Lock Building
Systems Ltd., Surrey, BC, Canada.
[0060] In particular embodiments of the invention, the insulating
concrete forms can be those available under the SAFE Block.RTM.
trade name from SYNTHEON Inc., Pittsburgh, Pa. A non-limiting
example of this embodiment is shown in FIGS: 5-10. In this
exemplary embodiment, insulating concrete form assembly 100
includes footer section 102 and wall section 104, all held together
by connecting members 106.
[0061] Wall section 104 includes first panel member 108 having
first outer panel side 110 including a first wall surface area
extending generally vertically thereon; first inner panel side 112
positioned oppositely from first outer panel side 110; and at least
two first slots 114 in first inner panel side 112 adapted to accept
connecting members 106; second panel member 116 includes second
outer panel side 118 including a second wall surface area extending
generally vertically thereon and facing oppositely from first panel
member 108, second inner panel side 120 positioned oppositely from
second outer panel side 118 and facing first inner panel side 112
of first panel member 108; and at least two second slots 122 in
second inner panel side 120 adapted to accept connecting member
106. At least two connecting members 106 detachable and securable
with respect to first panel member 108 and second panel member 116
adapted to maintain a spatial distance therebetween for defining
molding chamber 124 therebetween.
[0062] In embodiments of the invention shown in FIG. 8, connecting
members 106 include first flange 126 adapted to be detachably and
securably extending within first slot 114 of first panel member
108; a second flange 128 adapted to be detachably and securably
extending within second slot 122 of second panel member 116; and
mid-section portion 130 adapted to span the distance between first
inner panel side 112 and second inner panel side 120. Connecting
member 106 can optionally include one or more rebar holders 132
adapted to secure a portion of a reinforcing bar against inner
surface 134.
[0063] In other embodiments of the invention shown in FIGS. 9 and
10, connecting members 106 can include first flange 126 adapted to
be detachably and securably extending within first slot 114 of
first panel member 108; second flange 128 adapted to be detachably
and securably extending within second slot 122 of second panel
member 116; and mid-section portion 130 adapted to span the
distance between first inner panel side 112 and second inner panel
side 120. Connecting member 106 can optionally include one or more
raised portions 129 adapted to hold a portion of a reinforcing bar
in place and in contact with a surface of mid-section portion
130.
[0064] A variety of connecting members are known in the art and the
panels used in the present exemplary embodiment can be adapted to
use them. Non-limiting examples of such connecting members are
disclosed in U.S. Pat. Nos. 7,032,357; 6,378,260; 5,809,728;
5,890,337; 5,701,710; 4,889,310; and 4,884,382; the relevant
portions of which are incorporated herein by reference.
[0065] In embodiments of the invention, connecting members 106 and
connectors 28, 36, 44 and 46 can be made of plastics, metal,
construction grade plastics, composite materials, ceramics, and the
like.
[0066] Suitable plastics include homopolymers and copolymers of
styrene, homopolymers and copolymers of C.sub.2 to C.sub.20
olefins, C.sub.4 to C.sub.20 dienes, polyesters, polyamides,
homopolymers and copolymers of C.sub.2 to C.sub.20 (meth)acrylate
esters, polyetherimides, polycarbonates, polyphenylethers,
polyvinylchlorides, polyurethanes, and combinations thereof.
[0067] Suitable construction grade plastics include, but are not
limited to reinforced thermoplastics, thermoset resins, and
reinforced thermoset resins. Suitable thermoplastics include
polymers and polymer foams made up of materials that can be
repeatedly softened by heating and hardened again on cooling.
Suitable thermoplastic polymers include, but are not limited to
homopolymers and copolymers of styrene, homopolymers and copolymers
of C.sub.2 to C.sub.20 olefins, C.sub.4 to C.sub.20 dienes,
polyesters, polyamides, homopolymers and copolymers of C.sub.2 to
C.sub.20 (meth)acrylate esters, polyetherimides, polycarbonates,
polyphenylethers, polyvinylchlorides, polyurethanes, and
combinations thereof.
[0068] Suitable thermoset resins are resins that when heated to
their cure point, undergo a chemical cross-linking reaction causing
them to solidify and hold their shape rigidly, even at elevated
temperatures. Suitable thermoset resins include, but are not
limited to alkyd resins, epoxy resins, diallyl phthalate resins,
melamine resins, phenolic resins, polyester resins, urethane
resins, and urea, which can be crosslinked by reaction, as
non-limiting examples, with diols, triols, polyols, and/or
formaldehyde.
[0069] Reinforcing materials and/or fillers that can be
incorporated into the thermoplastics and/or thermoset resins
include, but are not limited to carbon fibers, aramid fibers, glass
fibers, metal fibers, woven fabric or structures of the mentioned
fibers, fiberglass, carbon black, graphite, clays, calcium
carbonate, titanium dioxide, woven fabric or structures of the
above-referenced fibers, and combinations thereof.
[0070] A non-limiting example of construction grade plastics are
thermosetting polyester or vinyl ester resin systems reinforced
with fiberglass that meet the requirements of required test methods
known in the art, non-limiting examples being ASTM D790, ASTM D695,
ASTM D3039 and ASTM D638.
[0071] The thermoplastics and thermoset resins can optionally
include other additives, as a non-limiting example ultraviolet (UV)
stabilizers, heat stabilizers, flame retardants, structural
enhancements, biocides, and combinations thereof.
[0072] Suitable metals include, but are not limited to, aluminum,
steel, stainless steel, tungsten, molybdenum, iron and alloys and
combinations of such metals. In a particular embodiment of the
invention, the metal bars, studs, joists and/or members are made of
a light gauge metal.
[0073] First panel 108 can include a first slot 136 spanning the
vertical length of a first end of panel 108 and a first raised
tongue 138 spanning the vertical length of a second end of panel
108. Second panel 116 can include a second slot 140 spanning the
vertical length of a first end of panel 116 and a second raised
tongue 142 spanning the vertical length of a second end of panel
116.
[0074] Adjacent wall sections 104 are adapted to be joined together
by, for example inserting tongue 138 into slot 136 of an adjacent
wall section 104 and inserting tongue 142 of adjacent wall section
104 into slot 140.
[0075] First panel 108 can include a first raised portion 144
spanning the horizontal length of a top surface of panel 108 and a
first groove section 146 spanning the horizontal length of a bottom
surface of panel 108. Second panel 116 can include a second raised
portion 148 spanning the horizontal length of a top surface of
panel 116 and a second groove section 150 spanning the horizontal
length of a bottom surface of panel 116.
[0076] Top and bottom wall sections 104 are adapted to be joined
together by, for example inserting raised portion 144 of bottom
wall section 104 into groove 146 of top wall section 104 and raised
portion 148 of bottom wall section 104 into groove 150 of top wall
section 104. Lower portion 127 of connecting member 106 extends
into slots in bottom wall section 104 and upper portion 131 extends
into slots in top wall section 104 to hold the two sections firmly
together.
[0077] Footer section 102 includes first footer panel 160, second
footer panel 162 and two or more connecting members 106. First
footer panel 160 includes upper leg 164, mid leg section 166, lower
leg 168, first footer outer side 170, first inner footer side 172
positioned oppositely from outer side 170, and at least two first
footer slots 174 adapted to accept connecting member 106. Second
footer panel 162 includes upper leg 176, mid leg section 178, lower
leg 180, second footer outer side 182, second inner footer side 184
positioned oppositely from outer side 182, and at least two second
footer slots 186 adapted to accept connecting member 106.
[0078] Connecting members 106 are adapted to be detachably and
securably extending within first slot 174 of first footer panel 160
and within second slot 186 of second footer panel 162. Mid-section
portion 130 is adapted to span the distance between first inner
side 172 and second inner side 184. At least two connecting members
106 detachable and securable with respect to first footer panel 160
and second footer panel 162 adapted to maintain a spatial distance
therebetween for defining molding chamber 183 therebetween.
[0079] First panel 160 can include a first groove portion 190
spanning the horizontal length of a top surface of panel 160 and a
second groove portion 192 spanning the horizontal length of a
bottom surface of panel 160. Second panel 162 can include a first
groove portion 194 spanning the horizontal length of a top surface
of panel 162 and a second groove portion 196 spanning the
horizontal length of a bottom surface of panel 162.
[0080] First panel 108 can include a first slot 136 spanning the
vertical length of a first end of panel 108 and a first raised
tongue 138 spanning the vertical length of a second end of panel
108. Second panel 116 can include a second slot 140 spanning the
vertical length of a first end of panel 116 and a second raised
tongue 142 spanning the vertical length of a second end of panel
116.
[0081] Wall section 104 is adapted to be placed on top of footer
section 102, for example inserting first raised tongue 138 of wall
section 104 into first groove portion 190 of footer section 102 and
second raised tongue 142 of wall section 104 into first groove
portion 194 of footer section 102. Lower portion 127 of connecting
member 106 extends into slots 174 in footer section 102 and upper
portion 131 extends into slots in wall section 104 to hold footer
section 102 and wall section 104 firmly together as shown, for
example, in FIG. 6.
[0082] Adjacent footer sections 102 are adapted to be joined
together by, for example inserting first tongue 198 extending from
a first edge of footer section 102 into first slot 200 of a second
edge of an adjacent footer section 102 and inserting second tongue
202 of adjacent footer section 102 into second slot 204.
[0083] When used according to the present invention, rebar 181 is
typically placed in footer sections 102 and wall section 104 prior
to placing concrete into insulating concrete form assembly 100. In
many cases, the rebar can extend from insulating concrete form
assembly 100 to adjacent insulating concrete form assemblies 100
and/or adjacent insulating pier forms 10.
[0084] In embodiments of the invention, at least some of the rebar
is held in place using rebar holders 132 or raised portions 129 of
connecting members 106.
[0085] In embodiments of the invention, water impervious fabric 179
is placed over an outward facing surface of insulating concrete
form assembly 100. As shown in FIG. 6, water impervious fabric 179
covers outer surfaces 118 and 178 of insulating concrete form
assembly 100.
[0086] In an embodiment of the invention, as shown in FIG. 13,
insulating concrete form assemblies 100 and insulating pier forms
10 are adapted to fit together and form continuous wall unit 200.
In this embodiment, insulating pier forms 10 are placed at the
corners of the foundation perimeter and, optionally, spaced along
the perimeter and one or more insulating concrete form assemblies
100 bridge the distance between insulating pier forms 10. Further
to this embodiment, at least a portion of the outer facing surface
of one or more of first panel member 16, second panel member 22,
third panel member 30 and fourth panel member 38 of post portion
14; and first panel member 50, second panel member 56, third panel
member 64 and fourth panel member 72 of footer portion 12 of
insulating pier forms 10 serve to define a concrete mold cavity
further defined by molding chamber 124 of wall section 104 and/or
molding chamber 183 of footer section 102 of insulating concrete
form assemblies 100.
[0087] In typical embodiments of the invention, the distance from
first panel member 16 to third panel member 30 ("first length") can
be the same or different than the distance from second panel member
22 to fourth panel member 38 ("second length") of post portion 14
of insulating pier form 10. The first length and/or second length
can be at least about 12 inches (0.3 m), in some cases at least
about 16 inches (0.4 m) and in other cases at least about 20 inches
(0.5 m) and can be up to about 60 inches (1.5 m), in some cases up
to about 51 inches (1.3 m) and in other cases up to about 47 inches
(1.2 m). The first length and/or second length of the post portion
14 of insulating pier form 10 can independently be any of the
values or range between any of the values recited above.
[0088] Further to this embodiment, the distance from first panel
member 50 to third panel member 54 ("first length") can be the same
or different than the distance from second panel member 56 to
fourth panel member 72 ("second length") of footer portion 12 of
insulating pier form 10 is typically greater than the first length
and/or second length of the post portion 14 of insulating pier form
10. As such, the first length and/or second length of footer
portion 12 can be at least about 14 inches (0.35 m), in some cases
at least about 18 inches (0.45 m) and in other cases at least about
22 inches (0.55 m) and can be up to about 63 inches (1.6 m), in
some cases up to about 55 inches (1.4 m) and in other cases up to
about 51 inches (1.3 m). The first length and/or second length of
the footer portion 12 of insulating pier form 10 can independently
be any of the values or range between any of the values recited
above.
[0089] The length of insulating concrete form assemblies 100 can be
described in terms of the distance from the first end of panel 108
to the second end of panel 108 and/or the distance from the first
edge of footer section 102 to the second edge of footer section
102. As such, insulating concrete form assemblies 100 can have a
length of from at least about 2 feet (0.6 m), in some cases at
least about 2.5 feet (0.76 m) and in other cases at least about 3
feet (0.91 m) and can be up to about 10 feet (3 m), in some cases
up to about 8 feet (2.4 m) and in other cases up to about 6 feet
(1.8 m). The length of insulating concrete form assemblies 100 can
be any of the values or range between any of the values recited
above.
[0090] In many embodiments of the invention, the width of footer
section 102, as measured from inner footer side 172 of lower leg
168 of first footer panel 160 to inner footer side 184 of lower leg
180 of second footer panel 162 is greater than or equal to the
width of wall section 104 as measured from first inner panel side
112 of first panel member 108 to second inner panel side 120 of
second panel member 116.
[0091] As such, the width of wall section 104 can be at least about
3 in. (7.6 cm), in some cases at least about 4 in. (10.2 cm) and in
other cases at least about 5 inches (12.7 cm) and can be up to
about 24 inches (61 cm), in some cases up to about 20 inches (51
cm) and in other cases up to about 16 inches (41 cm). The width of
wall section 104 can be any of the values or range between any of
the values recited above.
[0092] The width of footer section 102 can be at least about 4 in.
(10.2 cm), in some cases at least about 5 in. (12.7 cm) and in
other cases at least about 6 inches (15.2 cm) and can be up to
about 36 inches (91 cm), in some cases up to about 30 inches (76
cm) and in other cases up to about 24 inches (61 cm). The width of
footer section 102 can be any of the values or range between any of
the values recited above.
[0093] The height of wall section 104 can be measured as the
vertical length of the first end of panel 108. The height of footer
section 102 can be measured as the vertical distance from the
bottom surface of panel 160 to the base of first raised portion 190
of panel 160. Wall section 104 and footer section 102 can have the
same or different heights. As such, the height of wall section 104
and/or footer section 102 can independently be at least about 3 in.
(7.6 cm), in some cases at least about 4 in. (10.2 cm) and in other
cases at least about 5 inches (12.7 cm) and can be up to about 24
inches (61 cm), in some cases up to about 20 inches (51 cm) and in
other cases up to about 16 inches (41 cm). The height of wall
section 104 and/or footer section 102 can be any value or range
between any of the values recited above.
[0094] The vertical height of insulating concrete form assembly 100
is determined by the intended number of courses of wall sections
104 and/or footer section 102 to be used in an overall insulating
concrete wall design and corresponds to the sum of those
heights.
[0095] In embodiments of the invention, prior to using the
insulating pier forms and insulating concrete forms according to
the invention a trench, ditch or other excavation is dug along the
perimeter of an intended building. Typically, the excavation is
wider than the width of the insulating pier forms and insulating
concrete forms and in many cases at least twice as wide as the
insulating pier forms and insulating concrete forms to allow space
for placing and otherwise working with the forms, rebar and
concrete required for a specific construction project.
[0096] After the excavation has been completed, the plurality of
insulating pier forms are placed along the proposed building
perimeter and the plurality of insulating concrete forms are placed
between the insulating piers to form a continuous insulating
surface to the surrounding soil. In some embodiments, the
insulating pier forms and insulating concrete forms are placed
sequentially proceeding around the perimeter of the excavation.
[0097] Once the plurality of insulating pier forms and insulating
concrete forms are placed, rebar is placed in the forms as required
and a concrete composition is placed in the insulating piers and
insulating concrete forms and allowed to cure and harden.
[0098] Fill can then be placed in the space between the excavation
and the outer and inner surfaces of the insulating concrete
structure formed with the insulating pier forms, insulating
concrete forms, rebar and concrete composition.
[0099] The insulating inner surface of the concrete structure
together with the dirt and fill surface therebetween provides a
continuous forming surface for a slab form. In many cases, gravel,
stone, utility lines, heating lines, expansion joints, or other
desirable under concrete material and/or items as are known in the
art are placed along the continuous forming surface. A concrete
composition is then placed to within the continuous forming surface
and allowed to cure and harden to form a concrete slab within the
concrete structure.
[0100] In embodiments of the invention shown in FIG. 14, insulating
pier form 301 is placed at a corner of concrete structure 300 and
has rebar 302 and concrete 304 placed in mold chamber 306. Water
impervious fabric 307 is placed over the outward facing surface of
insulating pier form 301. Outer fill 308 is placed in the excavated
space between insulating pier form 301 and undisturbed ground 310
and is in contact with water impervious fabric 307. Inner fill 312
is placed in the excavated space between insulating pier form 300
and undisturbed ground 314. Crushed stone 316 is placed as a
surface onto which slab 318 is placed. Slab 318 is reinforced with
rebar 320. Load bearing column 322 is placed on top of concrete 304
and attached by way of connectors 324, which can be embedded in,
anchored in or otherwise secured to concrete 304.
[0101] In other embodiments of the invention shown in FIG. 15,
insulating concrete form 352 is placed along an excavated perimeter
of concrete structure 350 and has rebar 354 and concrete 356 placed
in mold chamber 358. Water impervious fabric 359 is placed over the
outward facing surface of insulating concrete form 352. Outer fill
360 is placed in the excavated space between insulating concrete
form 352 and undisturbed ground 310 and is in contact with water
impervious fabric 359. Inner fill 364 is placed in the excavated
space between insulating concrete form 352 and undisturbed ground
366. Crushed stone 368 is placed as a surface onto which slab 370
is placed. Slab 370 is reinforced with rebar 372. Wall 322 is
placed on top of concrete 356 and attached by way of base channel
372, which can be embedded in, anchored in or otherwise secured to
concrete 356.
[0102] In embodiments of the invention as shown in FIG. 16, frost
wall 400 includes insulating pier form 402 with concrete 404 and
rebar 406 therein, first insulating concrete form 408 and second
insulating concrete form 410, the surface of each can optionally be
covered by a water impervious fabric. In this embodiment, footer
portion 412 of insulating pier form 402 extends further into
undisturbed ground 414 than first insulating concrete form 408 and
second insulating concrete form 410. A portion of bottom surface
416 of first insulating concrete form 408 rests on top surface 418
of footer portion 412 of insulating pier form 402 and the remainder
of bottom surface 416 of first insulating concrete form 408 rests
on undisturbed ground 414. Similarly, a portion of bottom surface
420 of second insulating concrete form 410 rests on top surface 422
of footer portion 412 of insulating pier form 402 and the remainder
of bottom surface 420 of second insulating concrete form 410 rests
on undisturbed ground 414.
[0103] In other embodiments of the invention as shown in FIG. 17,
frost wall 450 includes insulating pier form 452 with concrete 454
and rebar 456 therein, first insulating concrete form 458 and
second insulating concrete form 460 the surface of each can
optionally be covered by a water impervious fabric. In this
embodiment, footer portion 452 of insulating pier form 462 extends
to the same depth of undisturbed ground 454 as first insulating
concrete form 458 and second insulating concrete form 460. A
portion of bottom surface 466 of first insulating concrete form 458
is cut away to conform to the shape of footer portion 462 of
insulating pier form 452 and the remainder of bottom surface 466 of
first insulating concrete form 458 is at the same depth as the
bottom of insulating pier form 452. Similarly, a portion of bottom
surface 468 of second insulating concrete form 460 is cut away to
conform to the shape of footer portion 462 of insulating pier form
452 and the remainder of bottom surface 468 of second insulating
concrete form 460 is at the same depth as the bottom of insulating
pier form 452.
[0104] A particular advantage of using the systems, methods and
articles for constructing a shallow pier foundation or pier and
floating slab building according to the present invention is that
it provides improved resistance from frost heave in general and to
vertical and lateral movements of the soil, occurring as a result
of mud, frost, thawing, etc., in particular. Additionally, the
present structures and methods provide improved economy as the
construction process can be completed in a shorter period of time.
Thus, the present invention provides improved systems, methods and
structures allowing more secure support in an arrangement and/or
system for pier and floating slab foundations, and which minimize
and/or eliminate the deficiencies in the prior art.
[0105] The insulating pier forms and insulating concrete forms
described herein ("mold units") are made of a foamed plastic that
can be produced by expanding an expandable polymer matrix. The
expanded polymer matrix typically includes expandable thermoplastic
particles. These expandable thermoplastic particles are made from
any suitable thermoplastic homopolymer or copolymer. Particularly
suitable for use are homopolymers derived from vinyl aromatic
monomers including styrene, isopropylstyrene, alpha-methylstyrene,
nuclear methylstyrenes, chlorostyrene, tert-butylstyrene, and the
like, as well as copolymers prepared by the copolymerization of at
least one vinyl aromatic monomer as described above with one or
more other monomers, non-limiting examples being divinylbenzene,
conjugated dienes (non-limiting examples being butadiene, isoprene,
1,3- and 2,4-hexadiene), alkyl methacrylates, alkyl acrylates,
acrylonitrile, and maleic anhydride, wherein the vinyl aromatic
monomer is present in at least 50% by weight of the copolymer. In
an embodiment of the invention, styrenic polymers are used,
particularly polystyrene. However, other suitable polymers can be
used, such as polyolefins (e.g., polyethylene, polypropylene),
polycarbonates, polyphenylene oxides, and mixtures thereof.
[0106] In a particular embodiment of the invention, the expandable
thermoplastic particles are expandable polystyrene (EPS) particles.
These particles can be in the form of beads, granules, or other
particles convenient for the expansion and molding operations.
Particles polymerized in an aqueous suspension process are
essentially spherical and are useful for molding the mold units
and/or forms described herein below. These particles can be
screened so that their size ranges from about 0.008 inches (0.2 mm)
to about 0.16 inches (4 mm).
[0107] In an embodiment of the invention, resin beads (unexpanded)
containing any of the polymers or polymer compositions described
herein have a particle size of at least 0.2 mm, in some situations
at least 0.33 mm, in some cases at least 0.35 mm, in other cases at
least 0.4 mm, in some instances at least 0.45 mm and in other
instances at least 0.5 mm. Also, the resin beads can have a
particle size of up to about 4 mm, in some situations up to about
3.5 mm, in other situations up to about 3 mm, in some instances up
to 2 mm, in other instances up to 2.5 mm, in some cases up to 2.25
mm, in other cases up to 2 mm, in some situations up to 1.5 mm and
in other situations up to 1 mm. The resin beads used in this
embodiment can be any value or can range between any of the values
recited above.
[0108] The average particle size and size distribution of the
expandable resin beads or pre-expanded resin beads can be
determined using low angle light scattering, which can provide a
weight average value. As a non-limiting example, a Model LA-910
Laser Diffraction Particle Size Analyzer available from Horiba
Ltd., Kyoto, Japan can be used
[0109] As used herein, the terms "expandable thermoplastic
particles" or "expandable resin beads" refers to a polymeric
material in particulate or bead form that is impregnated with a
blowing agent such that when the particulates and/or beads are
placed in a mold or expansion device and heat is applied thereto,
evaporation of the blowing agent (as described below) effects the
formation of a cellular structure and/or an expanding cellular
structure in the particulates and/or beads. When expanded in a
mold, the outer surfaces of the particulates and/or beads fuse
together to form a continuous mass of polymeric material conforming
to the shape of the mold.
[0110] As used herein, the terms "pre-expanded thermoplastic
particles", "pre-expanded resin beads" or "prepuff" refers to
expandable resin beads that have been expanded, but not to their
maximum expansion factor and whose outer surfaces have not fused.
As used herein, the term "expansion factor" refers to the volume a
given weight of resin bead occupies, typically expressed as cc/g.
Pre-expanded resin beads can be further expanded in a mold where
the outer surfaces of the pre-expanded resin beads fuse together to
form a continuous mass of polymeric material conforming to the
shape of the mold.
[0111] The expandable thermoplastic particles can be impregnated
using any conventional method with a suitable blowing agent. As a
non-limiting example, the impregnation can be achieved by adding
the blowing agent to the aqueous suspension during the
polymerization of the polymer, or alternatively by re-suspending
the polymer particles in an aqueous medium and then incorporating
the blowing agent as taught in U.S. Pat. No. 2,983,692. Any gaseous
material or material which will produce gases on heating can be
used as the blowing agent. Conventional blowing agents include
aliphatic hydrocarbons containing 4 to 6 carbon atoms in the
molecule, such as butanes, pentanes, hexanes, and the halogenated
hydrocarbons, e.g., CFC's and HCFC's, which boil at a temperature
below the softening point of the polymer chosen. Mixtures of these
aliphatic hydrocarbon blowing agents can also be used.
[0112] Alternatively, water can be blended with these aliphatic
hydrocarbons blowing agents or water can be used as the sole
blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and
6,242,540 in these patents, water-retaining agents are used. The
weight percentage of water for use as the blowing agent can range
from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and
6,242,540 are incorporated herein by reference.
[0113] The impregnated thermoplastic particles are generally
pre-expanded to a density of at least 0.5 lb/ft.sup.3, in some
cases at least 0.75 lb/ft.sup.3, in other cases at least 1.0
lb/ft.sup.3, in some situations at least 1.25 lb/ft.sup.3, in other
situations at least 1.5 lb/ft.sup.3, and in some instances at least
about 1.75 lb/ft.sup.3. Also, the density of the impregnated
pre-expanded particles can be up to 12 lb/ft.sup.3, in some cases
up to 10 lb/ft.sup.3, and in other cases up to 5 lb/ft.sup.3. The
density of the impregnated pre-expanded particles can be any value
or range between any of the values recited above. The pre-expansion
step is conventionally carried out by heating the impregnated beads
via any conventional heating medium, such as steam, hot air, hot
water, or radiant heat. One generally accepted method for
accomplishing the pre-expansion of impregnated thermoplastic
particles is taught in U.S. Pat. No. 3,023,175.
[0114] The impregnated thermoplastic particles can be foamed
cellular polymer particles as taught in U.S. Publication
Application No. 2002/0117769, the teachings of which are
incorporated herein by reference. The foamed cellular particles can
be polystyrene that are pre-expanded and contain a volatile blowing
agent at a level of less than 14 wt. %, in some situations less
than 8 wt. %, in some cases ranging from about 2 wt. % to about 7
wt. %, and in other cases ranging from about 2.5 wt. % to about 6.5
wt. % based on the weight of the polymer.
[0115] The thermoplastic particles according to the invention can
include an interpolymer of a polyolefin and in situ polymerized
vinyl aromatic monomers. Non-limiting examples of such
interpolymers are disclosed in U.S. Pat. Nos. 4,303,756 and
4,303,757 and U.S. Application Publication 2004/0152795, the
relevant portions of which are herein incorporated by reference. A
non-limiting example of interpolymers that can be used in the
present invention include those available under the trade name
ARCEL.RTM., available from NOVA Chemicals Inc., Pittsburgh, Pa. and
PIOCELAN.RTM., available from Sekisui Plastics Co., Ltd., Tokyo,
Japan.
[0116] The expanded polymer matrix can include customary
ingredients and additives, such as pigments, dyes, colorants,
plasticizers, mold release agents, stabilizers, ultraviolet light
absorbers, mold prevention agents, antioxidants, and so on. Typical
pigments include, without limitation, inorganic pigments such as
carbon black, graphite, expandable graphite, zinc oxide, titanium
dioxide, and iron oxide, as well as organic pigments such as
quinacridone reds and violets and copper phthalocyanine blues and
greens.
[0117] In a particular embodiment of the invention, the pigment is
carbon black, a non-limiting example of such a material being EPS
SILVER.RTM., available from NOVA Chemicals Inc.
[0118] In another particular embodiment of the invention, the
pigment is graphite, a non-limiting example of such a material
being NEOPOR.RTM., available from BASF Aktiengesellschaft Corp.,
Ludwigshafen am Rhein, Germany.
[0119] The pre-expanded particles or "pre-puff" are usually heated
in a closed mold to form the present mold units.
[0120] Any suitable type of concrete composition can be used to
make the concrete piers, walls and concrete foundation systems
described herein. The specific type of concrete will depend on the
desired and designed properties of the concrete piers, walls and
foundation systems. In embodiments of the invention, the concrete
includes one or more hydraulic cement compositions selected from
Portland cements, pozzolana cements, gypsum cements, aluminous
cements, magnesia cements, silica cements, and slag cements.
[0121] In an embodiment of the invention, the cement includes a
hydraulic cement composition. The hydraulic cement composition can
be present at a level of at least 3, in certain situations at least
5, in some cases at least 7.5, and in other cases at least 9 volume
percent and can be present at levels up to 40, in some cases up to
35, in other cases up to 32.5, and in some instances up to 30
volume percent of the cement mixture. The cement mixture can
include the hydraulic cement composition at any of the above-stated
levels or at levels ranging between any of levels stated above.
[0122] In an embodiment of the invention, the concrete mixture can
optionally include other aggregates and adjuvants known in the art
including but not limited to sand, additional aggregate,
plasticizers and/or fibers. Suitable fibers include, but are not
limited to glass fibers, silicon carbide, aramid fibers, polyester,
carbon fibers, composite fibers, fiberglass, metal and combinations
thereof as well as fabric containing the above-mentioned fibers,
and fabric containing combinations of the above-mentioned
fibers.
[0123] Non-limiting examples of fibers that can be used in the
invention include MeC-GRID.RTM. and C-GRID.RTM. available from
TechFab, LLC, Anderson, S.C., KEVLAR.RTM. available from E.I. du
Pont de Nemours and Company, Wilmington, Del., TWARON.RTM.
available from Teijin Twaron B.V., Arnheim, the Netherlands,
SPECTRA.RTM. available from Honeywell International Inc.,
Morristown, N.J., DACRON.RTM. available from Invista North America
S.A.R.L. Corp. Wilmington, Del., and VECTRAN.RTM. available from
Hoechst Celanese Corp., New York, N.Y. The fibers can be used in a
mesh structure, intertwined, interwoven, and oriented in any
desirable direction.
[0124] In a particular embodiment of the invention, fibers can make
up at least 0.1, in some cases at least 0.5, in other cases at
least 1, and in some instances at least 2 volume percent of the
concrete composition. Further, fibers can provide up to 10, in some
cases up to 8, in other cases up to 7, and in some instances up to
5 volume percent of the concrete composition. The amount of fibers
is adjusted to provide desired properties to the concrete
composition. The amount of fibers can be any value or range between
any of the values recited above.
[0125] Further to this embodiment, the additional aggregate can
include, but is not limited to, one or more materials selected from
common aggregates such as sand, stone, and gravel. Common
lightweight aggregates can include ground granulated blast furnace
slag, fly ash, glass, silica, expanded slate and clay; insulating
aggregates such as pumice, perlite, vermiculite, scoria, and
diatomite; light-weight aggregate such as expanded shale, expanded
slate, expanded clay, expanded slag, fumed silica, pelletized
aggregate, extruded fly ash, tuff, and macrolite; and masonry
aggregate such as expanded shale, clay, slate, expanded blast
furnace slag, sintered fly ash, coal cinders, pumice, scoria, and
pelletized aggregate.
[0126] When included, the other aggregates and adjuvants are
present in the concrete mixture at a level of at least 0.5, in some
cases at least 1, in other cases at least 2.5, in some instances at
least 5 and in other instances at least 10 volume percent of the
concrete mixture. Also, the other aggregates and adjuvants can be
present at a level of up to 95, in some cases up to 90, in other
cases up to 85, in some instances up to 65 and in other instances
up to 60 volume percent of the concrete mixture. The other
aggregates and adjuvants can be present in the concrete mixture at
any of the levels indicated above or can range between any of the
levels indicated above.
[0127] In embodiments of the invention, the concrete compositions
can contain one or more additives, non-limiting examples of such
being anti-foam agents, water-proofing agents, dispersing agents,
set-accelerators, set-retarders, plasticizing agents,
superplasticizing agents, freezing point decreasing agents,
adhesiveness-improving agents, and colorants. The additives are
typically present at less than one percent by weight with respect
to total weight of the composition, but can be present at from 0.1
to 3 weight percent.
[0128] Suitable dispersing agents or plasticizers that can be used
in the invention include, but are not limited to hexametaphosphate,
tripolyphosphate, polynaphthalene sulphonate, sulphonated polyamine
and combinations thereof.
[0129] Suitable plasticizing agents that can be used in the
invention include, but are not limited to polyhydroxycarboxylic
acids or salts thereof, polycarboxylates or salts thereof;
lignosulfonates, polyethylene glycols, and combinations
thereof.
[0130] Suitable superplasticizing agents that can be used in the
invention include, but are not limited to alkaline or earth
alkaline metal salts of lignin sulfonates; lignosulfonates,
alkaline or earth alkaline metal salts of highly condensed
naphthalene sulfonic acid/formaldehyde condensates; polynaphthalene
sulfonates, alkaline or earth alkaline metal salts of one or more
polycarboxylates (such as poly(meth)acrylates and the
polycarboxylate comb copolymers described in U.S. Pat. No.
6,800,129, the relevant portions of which are herein incorporated
by reference); alkaline or earth alkaline metal salts of
melamine/formaldehyde/sulfite condensates; sulfonic acid esters;
carbohydrate esters; and combinations thereof.
[0131] Suitable set-accelerators that can be used in the invention
include, but are not limited to soluble chloride salts (such as
calcium chloride), triethanolamine, paraformaldehyde, soluble
formate salts (such as calcium formate), sodium hydroxide,
potassium hydroxide, sodium carbonate, sodium sulfate,
12CaO.7Al.sub.2O.sub.3, sodium sulfate, aluminum sulfate, iron
sulfate, the alkali metal nitrate/sulfonated aromatic hydrocarbon
aliphatic aldehyde condensates disclosed in U.S. Pat. No.
4,026,723, the water soluble surfactant accelerators disclosed in
U.S. Pat. No. 4,298,394, the methylol derivatives of amino acids
accelerators disclosed in U.S. Pat. No. 5,211,751, and the mixtures
of thiocyanic acid salts, alkanolamines, and nitric acid salts
disclosed in U.S. Pat. No. Re. 35,194, the relevant portions of
which are herein incorporated by reference, and combinations
thereof.
[0132] Suitable set-retarders that can be used in the invention
include, but are not limited to lignosulfonates, hydroxycarboxylic
acids (such as gluconic acid, citric acid, tartaric acid, maleic
acid, salicylic acid, glucoheptonic acid, arabonic acid, and
inorganic or organic salts thereof such as sodium, potassium,
calcium, magnesium, ammonium and triethanolamine salt), cardonic
acid, sugars, modified sugars, phosphates, borates,
silico-fluorides, calcium bromate, calcium sulfate, sodium sulfate,
monosaccharides such as glucose, fructose, galactose, saccharose,
xylose, apiose, ribose and invert sugar, oligosaccharides such as
disaccharides and trisaccharides, such oligosaccharides as dextrin,
polysaccharides such as dextran, and other saccharides such as
molasses containing these; sugar alcohols such as sorbitol;
magnesium silicofluoride; phosphoric acid and salts thereof, or
borate esters; aminocarboxylic acids and salts thereof;
alkali-soluble proteins; humic acid; tannic acid; phenols;
polyhydric alcohols such as glycerol; phosphonic acids and
derivatives thereof, such as aminotri(methylenephosphonic acid),
1-hydroxyethylidene-1,1-diphosphonic acid,
ethylenediaminetetra(methylene-phosphonic acid),
diethylenetriaminepenta(methylenephosphonic acid), and alkali metal
or alkaline earth metal salts thereof, and combinations of the
set-retarders indicated above.
[0133] Suitable defoaming agents that can be used in the invention
include, but are not limited to silicone-based defoaming agents
(such as dimethylpolysiloxane, dimethylsilicone oil, silicone
paste, silicone emulsions, organic group-modified polysiloxanes
(polyorganosiloxanes such as dimethylpolysiloxane), fluorosilicone
oils, etc.), alkyl phosphates (such as tributyl phosphate, sodium
octylphosphate, etc.), mineral oil-based defoaming agents (such as
kerosene, liquid paraffin, etc.), fat- or oil-based defoaming
agents (such as animal or vegetable oils, sesame oil, castor oil,
alkylene oxide adducts derived therefrom, etc.), fatty acid-based
defoaming agents (such as oleic acid, stearic acid, and alkylene
oxide adducts derived therefrom, etc.), fatty acid ester-based
defoaming agents (such as glycerol monoricinolate, alkenylsuccinic
acid derivatives, sorbitol monolaurate, sorbitol trioleate, natural
waxes, etc.), oxyalkylene type defoaming agents, alcohol-based
defoaming agents: octyl alcohol, hexadecyl alcohol, acetylene
alcohols, glycols, etc.), amide-based defoaming agents (such as
acrylate polyamines, etc.), metal salt-based defoaming agents (such
as aluminum stearate, calcium oleate, etc.) and combinations of the
above-described defoaming agents.
[0134] Suitable freezing point decreasing agents that can be used
in the invention include, but are not limited to ethyl alcohol,
calcium chloride, potassium chloride, and combinations thereof.
[0135] Suitable adhesiveness-improving agents that can be used in
the invention include, but are not limited to polyvinyl acetate,
styrene-butadiene, homopolymers and copolymers of (meth)acrylate
esters, and combinations thereof.
[0136] Suitable water-repellent or water-proofing agents that can
be used in the invention include, but are not limited to fatty
acids (such as stearic acid or oleic acid), lower alkyl fatty acid
esters (such as butyl stearate), fatty acid salts (such as calcium
or aluminum stearate), silicones, wax emulsions, hydrocarbon
resins, bitumen, fats and oils, silicones, paraffins, asphalt,
waxes, and combinations thereof. Although not used in many
embodiments of the invention, when used, suitable air-entraining
agents include, but are not limited to vinsol resins, sodium
abietate, fatty acids and salts thereof, tensides,
alkyl-aryl-sulfonates, phenol ethoxylates, lignosulfonates, and
mixtures thereof.
[0137] In some embodiments of the invention, the concrete is light
weight concrete. As used herein, the term "light weight concrete"
refers to concrete where light-weight aggregate is included in a
cementitous mixture. Exemplary light weight concrete compositions
that can be used in the present invention are disclosed in U.S.
Pat. Nos. 3,021,291, 3,214,393, 3,257,338, 3,272,765, 5,622,556,
5,725,652, 5,580,378, and 6,851,235, U.S. Patent Application
Publication No. 2007/0125275 as well as JP 9 071 449, WO 98 02 397,
WO 00/61519, and WO 01/66485 the relevant portions of which are
incorporated herein by reference.
[0138] In particular embodiments of the present invention, the
lightweight concrete (LWC) composition includes a concrete mixture
and polymer particles. In many instances, the size, composition,
structure, and physical properties of expanded polymer particles,
and in some instances their resin bead precursors, can greatly
affect the physical properties of LWC used in the invention. Of
particular note is the relationship between bead size and expanded
polymer particle density on the physical properties of the
resulting LWC wall.
[0139] The polymer particles, which can optionally be expanded
polymer particles, are present in the LWC composition at a level of
at least 10, in some instances at least 15, in other instances at
least 20, in particular situations up to 25, in some cases at least
30, and in other cases at least 35 volume percent and up to 90, in
some cases up to 85, in other cases up to 78, in some instances up
to 75, in other instance up to 65, in particular instances up to
60, in some cases up to 50, and in other cases up to 40 volume
percent based on the total volume of the LWC composition. The
amount of polymer particles will vary depending on the particular
physical properties desired in a finished LWC wall. The amount of
polymer particles in the LWC composition can be any value or can
range between any of the values recited above.
[0140] The polymer particles can include any particles derived from
any suitable expandable thermoplastic material. The actual polymer
particles are selected based on the particular physical properties
desired in a finished LWC wall. As a non-limiting example, the
polymer particles, which can optionally be expanded polymer
particles, can include one or more polymers selected from
homopolymers of vinyl aromatic monomers; copolymers of at least one
vinyl aromatic monomer with one or more of divinylbenzene,
conjugated dienes, alkyl methacrylates, alkyl acrylates,
acrylonitrile, and/or maleic anhydride; polyolefins;
polycarbonates; polyesters; polyamides; natural rubbers; synthetic
rubbers; and combinations thereof.
[0141] In an embodiment of the invention, the polymer particles
include thermoplastic homopolymers or copolymers selected from
homopolymers derived from vinyl aromatic monomers including
styrene, isopropylstyrene, alpha-methylstyrene, nuclear
methylstyrenes, chlorostyrene, tert-butylstyrene, and the like, as
well as copolymers prepared by the copolymerization of at least one
vinyl aromatic monomer as described above with one or more other
monomers, non-limiting examples being divinylbenzene, conjugated
dienes (non-limiting examples being butadiene, isoprene, 1,3- and
2,4-hexadiene), alkyl methacrylates, alkyl acrylates,
acrylonitrile, and maleic anhydride, wherein the vinyl aromatic
monomer is present in at least 50% by weight of the copolymer. In
an embodiment of the invention, styrenic polymers are used,
particularly polystyrene. However, other suitable polymers can be
used, such as polyolefins (e.g., polyethylene, polypropylene),
polyearbonates, polyphenylene oxides, and mixtures thereof.
[0142] In a particular embodiment of the invention, the polymer
particles are expandable polystyrene (EPS) particles. These
particles can be in the form of beads, granules, or other
particles.
[0143] In the present invention, particles polymerized in a
suspension process, which are essentially spherical resin beads,
are useful as polymer particles or for making expanded polymer
particles. However, polymers derived from solution and bulk
polymerization techniques that are extruded and cut into particle
sized resin bead sections can also be used.
[0144] In an embodiment of the invention, resin beads (unexpanded)
containing any of the polymers or polymer compositions described
herein have a particle size of at least 0.2 mm, in some situations
at least 0.33 mm, in some cases at least 0.35 mm, in other cases at
least 0.4 mm, in some instances at least 0.45 mm and in other
instances at least 0.5 mm. Also, the resin beads can have a
particle size of up to 3 mm, in some instances up to 2 mm, in other
instances up to 2.5 mm, in some cases up to 2.25 mm, in other cases
up to 2 mm, in some situations up to 1.5 mm and in other situations
up to 1 mm. In this embodiment, the physical properties of LWC
walls made according to the invention have inconsistent or
undesirable physical properties when resin beads having particle
sizes outside of the above described ranges are used to make the
expanded polymer particles. The resin beads used in this embodiment
can be any value or can range between any of the values recited
above.
[0145] The expandable thermoplastic particles or resin beads can
optionally be impregnated using any conventional method with a
suitable blowing agent. As a non-limiting example, the impregnation
can be achieved by adding the blowing agent to the aqueous
suspension during the polymerization of the polymer, or
alternatively by re-suspending the polymer particles in an aqueous
medium and then incorporating the blowing agent as taught in U.S.
Pat. No. 2,983,692. Any gaseous material or material which will
produce gases on heating can be used as the blowing agent.
Conventional blowing agents include aliphatic hydrocarbons
containing 4 to 6 carbon atoms in the molecule, such as butanes,
pentanes, hexanes, and the halogenated hydrocarbons, e.g., CFC's
and HCFC's, which boil at a temperature below the softening point
of the polymer chosen. Mixtures of these aliphatic hydrocarbon
blowing agents can also be used.
[0146] Alternatively, water can be blended with these aliphatic
hydrocarbons blowing agents or water can be used as the sole
blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and
6,242,540 in these patents, water-retaining agents are used. The
weight percentage of water for use as the blowing agent can range
from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and
6,242,540 are incorporated herein by reference.
[0147] The impregnated polymer particles or resin beads are
optionally expanded to a bulk density of at least 1.75 lb/ft.sup.3
(0.028 g/cc), in some circumstances at least 2 lb/ft.sup.3 (0.032
g/cc) in other circumstances at least 3 lb/ft.sup.3 (0.048 g/cc)
and in particular circumstances at least 3.25 lb/ft.sup.3 (0.052
g/cc) or 3.5 lb/ft.sup.3 (0.056 g/cc). When non-expanded resin
beads are used, higher bulk density beads can be used. As such, the
bulk density can be as high as 40 lb/ft.sup.3 (0.64 g/cc). In other
situations, the polymer particles are at least partially expanded
and the bulk density can be up to 35 lb/ft.sup.3 (0.56 g/cc), in
some cases up to 30 lb/ft.sup.3 (0.48 g/cc), in other cases up to
25 lb/ft.sup.3 (0.4 g/cc), in some instances up to 20 lb/ft.sup.3
(0.32 g/cc), in other instances up to 15 lb/ft.sup.3 (0.24 g/cc)
and in certain circumstances up to 10 lb/ft.sup.3 (0.16 g/cc). The
bulk density of the polymer particles can be any value or range
between any of the values recited above. The bulk density of the
polymer particles, resin beads and/or prepuff particles is
determined by weighing a known volume of polymer particles, beads
and/or prepuff particles (aged 24 hours at ambient conditions).
[0148] The expansion step is conventionally carried out by heating
the impregnated beads via any conventional heating medium, such as
steam, hot air, hot water, or radiant heat. One generally accepted
method for accomplishing the pre-expansion of impregnated
thermoplastic particles is taught in U.S. Pat. No. 3,023,175.
[0149] The impregnated polymer particles can be foamed cellular
polymer particles as taught in U.S. Publication Application No.
2002/0117769, the teachings of which are incorporated herein by
reference. The foamed cellular particles can be polystyrene that
are expanded and contain a volatile blowing agent at a level of
less than 14 wt. %, in some situations less than 8 wt. %, in some
cases ranging from about 2 wt. % to about 7 wt. %, and in other
cases ranging from about 2.5 wt. % to about 6.5 wt. % based on the
weight of the polymer.
[0150] An interpolymer of a polyolefin and in situ polymerized
vinyl aromatic monomers that can be included in the expanded
thermoplastic resin or polymer particles according to the invention
is disclosed in U.S. Pat. Nos. 4,303,756 and 4,303,757 and U.S.
Application Publication 2004/0152795, the relevant portions of
which are herein incorporated by reference.
[0151] The polymer particles can include customary ingredients and
additives, such as flame retardants, pigments, dyes, colorants,
plasticizers, mold release agents, stabilizers, ultraviolet light
absorbers, mold prevention agents, antioxidants, rodenticides,
insect repellants, and so on. Typical pigments include, without
limitation, inorganic pigments such as carbon black, graphite,
expandable graphite, zinc oxide, titanium dioxide, and iron oxide,
as well as organic pigments such as quinacridone reds and violets
and copper phthalocyanine blues and greens.
[0152] In a particular embodiment of the invention, the pigment is
carbon black, a non-limiting example of such a material being EPS
SILVER.RTM., available from NOVA Chemicals Inc.
[0153] In another particular embodiment of the invention, the
pigment is graphite, a non-limiting example of such a material
being NEOPOR.RTM., available from BASF Aktiengesellschaft Corp.,
Ludwigshafen am Rhein, Germany.
[0154] When materials such as carbon black and/or graphite are
included in the polymer particles, improved insulating properties,
as exemplified by higher R values for materials containing carbon
black or graphite (as determined using ASTM-C518), are provided. As
such, the R value of the expanded polymer particles containing
carbon black and/or graphite or materials made from such polymer
particles are at least 5% higher than observed for particles or
resulting walls that do not contain carbon black and/or
graphite.
[0155] The expanded polymers can have an average particle size of
at least 0.2, in some circumstances at least 0.3, in other
circumstances at least 0.5, in some cases at least 0.75, in other
cases at least 0.9 and in some instances at least 1 mm and can be
up to 8, in some circumstances up to 6, in other circumstances up
to 5, in some cases up to 4, in other cases up to 3, and in some
instances up to 2.5 mm. When the size of the expanded polymer
particles is too small or too large, the physical properties of LWC
walls made using the present LWC composition can be undesirable.
The average particle size of the expanded polymer particles can be
any value and can range between any of the values recited above.
The average particle size of the expanded polymer particles can be
determined using laser diffraction techniques or by screening
according to mesh size using mechanical separation methods well
known in the art.
[0156] In an embodiment of the invention, the polymer particles or
expanded polymer particles have a minimum average cell wall
thickness, which helps to provide desirable physical properties to
LWC walls made using the present LWC composition. The average cell
wall thickness and inner cellular dimensions can be determined
using scanning electron microscopy techniques known in the art. The
expanded polymer particles can have an average cell wall thickness
of at least 0.15 .mu.m, in some cases at least 0.2 .mu.m and in
other cases at least 0.25 .mu.m. Not wishing to be bound to any
particular theory, it is believed that a desirable average cell
wall thickness results when resin beads having the above-described
dimensions are expanded to the above-described densities.
[0157] In an embodiment of the invention, the polymer beads are
optionally expanded to form the expanded polymer particles such
that a desirable cell wall thickness as described above is
achieved. Though many variables can impact the wall thickness, it
is desirable, in this embodiment, to limit the expansion of the
polymer bead so as to achieve a desired wall thickness and
resulting expanded polymer particle strength. Optimizing processing
steps and blowing agents can expand the polymer beads to a minimum
of 1.75 lb/ft.sup.3 (0.028 g/cc). This property of the expanded
polymer bulk density, can be described by pcf (lb/ft.sup.3) or by
an expansion factor (cc/g).
[0158] As used herein, the term "expansion factor" refers to the
volume a given weight of expanded polymer bead occupies, typically
expressed as cc/g.
[0159] In order to provide expanded polymer particles with
desirable cell wall thickness and strength, the expanded polymer
particles are not expanded to their maximum expansion factor; as
such, an extreme expansion yields particles with undesirably thin
cell walls and insufficient strength. Further, the polymer beads
can be expanded at least 5%, in some cases at least 10%, and in
other cases at least 15% of their maximum expansion factor.
However, so as not to cause the cell wall thickness to be too thin,
the polymer beads are expanded up to 80%, in some cases up to 75%,
in other cases up to 70%, in some instances up to 65%, in other
instances up to 60%, in some circumstances up to 55%, and in other
circumstances up to 50% of their maximum expansion factor. The
polymer beads can be expanded to any degree indicated above or the
expansion can range between any of the values recited above.
Typically, the polymer beads or prepuff beads do not further expand
when formulated into the present concrete compositions and do not
further expand while the concrete compositions set, cure and/or
harden.
[0160] The prepuff or expanded polymer particles typically have a
cellular structure or honeycomb interior portion and a generally
smooth continuous polymeric surface as an outer surface, i.e., a
substantially continuous outer layer. The smooth continuous surface
can be observed using scanning electron microscope (SEM) techniques
at 1000.times. magnification. SEM observations do not indicate the
presence of holes in the outer surface of the prepuff or expanded
polymer particles. Cutting sections of the prepuff or expanded
polymer particles and taking SEM observations reveals the generally
honeycomb structure of the interior of the prepuff or expanded
polymer particles.
[0161] The polymer particles or expanded polymer particles can have
any cross-sectional shape that allows for providing desirable
physical properties in LWC walls. In an embodiment of the
invention, the expanded polymer particles have a circular, oval or
elliptical cross-section shape. In embodiments of the invention,
the prepuff or expanded polymer particles have an aspect ratio of
1, in some cases at least 1 and the aspect ratio can be up to 3, in
some cases up to 2 and in other cases up to 1.5. The aspect ratio
of the prepuff or expanded polymer particles can be any value or
range between any of the values recited above.
[0162] In particular embodiments of the invention, the light weight
concrete includes from 10 to 90 volume percent of a cement
composition, from 10 to 90 volume percent of particles having an
average particle diameter of from 0.2 mm to 8 mm, a bulk density of
from 0.028 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and
from 10 to 50 volume percent of sand and/or other fine aggregate,
where the sum of components used does not exceed 100 volume
percent.
[0163] Light weight concrete compositions that are particularly
useful in the present invention include those disclosed in
co-pending U.S. Publication Application No. 2002/0117769, the
relevant portions of the disclosure are incorporated herein by
reference.
[0164] The present invention has been described with reference to
specific details of particular embodiments thereof. It is not
intended that such details be regarded as limitations upon the
scope of the invention except insofar as and to the extent that
they are included in the accompanying claims.
* * * * *