U.S. patent application number 10/131056 was filed with the patent office on 2003-10-30 for high performance door.
Invention is credited to Barker, W. Kip, Kepler, Steven P., Minke, Ronald C., Pagryzinski, William V., Redding, David R., Sentel, David A., Templeton, G. Daniel, West, Kenneth J..
Application Number | 20030200714 10/131056 |
Document ID | / |
Family ID | 29248540 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030200714 |
Kind Code |
A1 |
Minke, Ronald C. ; et
al. |
October 30, 2003 |
High performance door
Abstract
A high performance door comprising a door shell having a
generally planar construction with marginal edges and at least one
door skin helping to define an interior door cavity and a door
member disposed within the interior door cavity is disclosed. The
door member is preferably constructed of a gas-entrained
cementitious material and has a compressive strength of at least
about 30 lbf/in.sup.2 when measured using ASTM C-39. A method for
forming a door member for use in construction with the door
generally comprising: providing a door shell, placing the door
shell in a fixture, filling the interior door cavity with a
gas-entrained cementitious material, green-strength curing the
gas-entrained cementitious material, and removing the door shell
from the fixture is disclosed. The cured gas-entrained cementitious
material provides a gas-entrained cementitious core for use in
conjunction with a door.
Inventors: |
Minke, Ronald C.;
(Leo-Cedarville, IN) ; Redding, David R.; (Fort
Wayne, IN) ; Templeton, G. Daniel; (Fort Wayne,
IN) ; Pagryzinski, William V.; (Fort Wayne, IN)
; Sentel, David A.; (Angola, IN) ; West, Kenneth
J.; (Grabill, IN) ; Barker, W. Kip; (Fort
Wayne, IN) ; Kepler, Steven P.; (Leo-Cedarville,
IN) |
Correspondence
Address: |
BROOKS & KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Family ID: |
29248540 |
Appl. No.: |
10/131056 |
Filed: |
April 24, 2002 |
Current U.S.
Class: |
52/423 |
Current CPC
Class: |
E06B 2003/703 20130101;
B28B 19/00 20130101; E06B 3/825 20130101; E06B 2003/7028 20130101;
E06B 5/16 20130101; B28B 1/14 20130101; E06B 2003/7063 20130101;
E06B 2003/7067 20130101 |
Class at
Publication: |
52/423 |
International
Class: |
E04B 002/00 |
Claims
What is claimed is:
1. A high performance door comprising: a door shell having a
generally planar construction with marginal edges and at least one
door skin helping to define an interior door cavity; and a door
member disposed within the interior door cavity, the door member
being constructed of a gas-entrained cementitious material.
2. The high performance door of claim 1, wherein the door member
has a compressive strength of at least about 30 lbf/in.sup.2 when
measured using ASTM C-39.
3. The high performance door of claim 1, wherein the door member
has a density greater than about 2.6 lb/ft.sup.3.
4. The high performance door of claim 1 wherein the door shell is
comprised of a door frame and a first door skin and a second door
skin.
5. The high performance door of claim 1 wherein the door shell is
comprised of pre-pigmented plastic.
6. The high performance door of claim 1, wherein the high
performance door is fire resistant for a 20 minute fire rating test
using ASTM 2074-00, UL 1.degree. C., or UBC 7-2-1997 testing
standards.
7. The high performance door of claim 1, wherein the high
performance door is fire resistant for a 30 minute fire rating test
using the BSI 476/22 testing standard.
8. The high performance door of claim 1, wherein the high
performance door has a security rating of grade 20 according to
ASTM F-476.
9. The high performance door of claim 1 wherein the door shell is
comprised of a casing and the casing is positioned over the door
member and is secured with a securing means.
10. The high performance door of claim 1 wherein the door shell is
comprised of metal and is secured to the door member with an
adhesive.
11. The high performance door of claim 1, wherein the door member
is a cured product of a foamed cement slurry.
12. The high performance door of claim 11, wherein the foamed
cement slurry is comprised of a hydraulic cement and water.
13. The high performance door of claim 12, wherein the foamed
cement slurry further comprises a foaming agent.
14. The high performance door of claim 13, wherein the foamed
cement slurry further comprises at least one ingredient selected
from the group consisting of a water reducer, a setting
accelerator, and reinforcement fibers.
15. The high performance door of claim 12, wherein the hydraulic
cement includes a pozzolanic additive.
16. The high performance door of claim 12, wherein the hydraulic
cement includes a cementitious additive.
17. The high performance door of claim 15, wherein the pozzolanic
additive is selected from the group consisting of Class C fly ash,
Class F fly ash, pulverized-fuel fly ash, condensed silica fume,
metakaolin, rubber ash, and glass cullet.
18. The high performance door of claim 1 wherein the door shell is
comprised of an aesthetic layer applied to the door member.
19. The high performance door of claim 18 wherein the aesthetic
layer is comprised of a wood-like aesthetic layer.
20. The high performance door of claim 18 wherein the aesthetic
layer is comprised of an aesthetic surface layer.
21. The high performance door of claim 18 wherein the aesthetic
layer is comprised of a pre-pigmented aesthetic layer.
22. The high performance door of claim 18 wherein the aesthetic
layer is selected from the group consisting of wood veneers,
decorative films, transcribed pigment layers, polyvinylidene
chloride coated wood and organic polymer coating.
23. A method for forming a door member for use in conjunction with
a door, the method comprising: providing a form having a generally
planar construction wherein the material used to construct the form
does not readily adhere to a gas-entrained cementitious material;
filling the form with the gas-entrained cementitious material;
green-strength curing the gas-entrained cementitious material; and
removing the cured gas-entrained cementitious material from the
form wherein the cured gas-entrained cementitious material provides
a gas-entrained cementitious core for use in conjunction with a
door.
24. The method of claim 23 wherein the gas-entrained cementitious
material is comprised of a foamed cement slurry.
25. The method of claim 23, wherein the Material used to construct
the form is selected from the group consisting of ultrahigh
molecular weight polyethylene, high density polyethylene,
polypropylene, polycarbonate, and polyvinylidene chloride.
26. A method for forming a door member for use in conjunction with
a door, the method comprising: selecting a gas-entrained
cementitious material that has flowability of between about 4.825
inches and about 18 inches when tested using the TT flowability
method; casting the gas-entrained cementitious material into a
form; allowing the gas-entrained cementitious material to achieve
green-strength cure; and removing the gas-entrained cementitious
material from the form wherein the cured gas-entrained cementitious
material provides a gas-entrained cementitious material core for
use in conjunction with a door.
27. A method for forming a high performance door, the method
comprising: providing a door shell having a generally planer
construction with marginal edges and at least one door skin helping
to define an interior door cavity; placing the door shell in a
fixture; filling the interior door cavity with a gas-entrained
cementitious material; green-strength curing the gas-entrained
cementitious material; and removing the door shell from the fixture
wherein the cured gas-entrained cementitious material provides a
gas-entrained cementitious core for use in conjunction with a
door.
28. The method of claim 27 further comprising inserting a flexible,
non-ceramic compound into the interior door cavity prior to filling
the interior door cavity.
29. The method of claim 27, wherein the fixture is comprised of a
platen press.
30. The method of claim 27, wherein the placing the door shell in
the fixture is comprised of the following steps: placing the door
shell in an orientation such that the at least one door skins is
generally parallel with the ground; and running an at least one
roller over one of the door skins wherein excess gas-entrained
cementitious material is removed from the interior door cavity.
31. The method of claim 27 further comprising agitating the
gas-entrained cementitious material with an air vibrator to inhibit
the formation of voids in the gas-entrained cementitious
material.
32. The method of claim 27, wherein the door shell is comprised of
a first door skin having a first exposed outer surface and an first
opposed inner surface, a second door skin having a second exposed
outer surface and a second opposed inner surface, and a door frame,
the door frame being attached to the first opposed inner surface
and the second opposed inner surface.
33. The method of claim 32, wherein the door frame is comprised of
stiles and rails, wherein the stiles are constructed of laminated
wood and the rails are constructed of high-density
polyethylene-wood fiber and wherein the first door skin and second
door skin are comprised of fiberglass.
34. The method of claim 33 further comprising inserting a plurality
of nails into an at least one interior edge of the stiles prior to
filling the interior door cavity with the gas-entrained
cementitious material; wherein the plurality of nails serve to
connect the door frame to the gas-entrained cementitious core.
35. The method of claim 32 further comprising fastening a
reinforcement mat to an at least one interior edge of the door
frame.
36. The method of claim 35 wherein the reinforcement mat is
comprised of a metal mesh sheet.
37. The method of claim 36 wherein the metal mesh sheet is selected
from the group consisting of chicken wire, grill cloth, aluminum
screen, chain-linked fencing and expanded metal.
38. The method of claim 35 wherein the reinforcement mat is
comprised of a polymer mesh sheet.
39. The method of claim 38 wherein the polymer mesh sheet is
selected from the group consisting of polyethylene mesh, aramid
fiber mat, carbon fiber mat, nylon screen, rubber-coated textiles,
and plastic laminated fiber mat.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to a high performance
door, and more specifically, a high performance door that has a
gas-entrained cementitious core.
[0003] 2. Background Art
[0004] Several applications for residential and commercial entry
way doors require high levels of performance. For example, rated
fire doors, security doors, high insulation doors, rated sound
transmission reduction doors, and rated weather-resistant doors
have been manufactured for many years. The typical high performance
door, as well as other types of doors, include face surfaces, edge
surfaces, core materials, and adhesives. The face surfaces function
as an aesthetic layer, a barrier to light in the infrared and
visible wavelengths, a barrier to rain and wind, a stiffening
member, and a barrier to fire. The edge surfaces, through the use
of adhesives, act as a connecting element between the face
surfaces. In addition, the edge surfaces act as a substrate for
lock and hinge hardware. In conjunction with the face surfaces, the
edge surfaces act as a sealing surface for weather stripping. The
edge surfaces also serve as a stiffening member, a door
reinforcement, and a mating substrate connector. The core material
serves as a stiffening member, a connecting element between the
face surfaces, a barrier to light in the infrared and visible
wavelengths, a provider of bulk mass, and a barrier to fire. The
elements of the high performance door may have one element that
serves multiple purposes.
[0005] Current designs of high performance doors are either
substantially more costly than conventional doors and/or have
limited efficacy. For example, steel doors are often used as rated
fire doors. However, steel doors rust when not maintained, dent
readily, and transmit heat readily during fire tests. When filled
with polyurethane or expanded polystyrene foam cores, the steel
doors cannot pass standard 20 or 30 minute positive pressure fire
rating tests (ASTM 2074-00, UL 1.degree. C., UBC 7-2-1997 test or
British Standard 476, Section 22, hereinafter referred to as BSI
476/22) without affixing expensive intumescent seals to the steel
door frame. In addition, decorative panels with sharp embossments,
a feature highly desired by customers, typically cannot be stamped
into steel door skins.
[0006] Wood fire doors are typically heavy since they typically
incorporate a fire retardant core. The wood door faces will split
or crack if not maintained, and are generally unsuitable for
weather exposure for extended times due to moisture variations and
damage from the sun's ultraviolet rays. Moreover, wood fire doors
typically do not act as sufficient thermal insulators.
[0007] Fiberglass fire doors have been made with polyurethane
foam/gypsum board cores, mineral cores, and phenolic foam. These
doors are typically resistant to rusting, denting, cracking, and
splitting and require relatively low maintenance. However,
fiberglass fire doors regularly fail positive pressure fire tests.
In addition, fiberglass fire doors are substantially more expensive
than existing steel fire doors.
[0008] High insulation doors have been manufactured for many years.
High insulation doors conserve energy in residences and save lives
during fires, especially in institutions serving the physically
handicapped. In designing high insulation doors, one of the major
considerations is the stiffness of the door. To enhance the
stiffness in many high insulation doors, foamed rigid polyurethane
is commonly used as a core material. Even though foamed rigid
polyurethane is typically used, it suffers from relatively low
compression strength (from about 16 lbf/ft.sup.2 to about 20
lbf/ft.sup.2), a relatively low Young's modulus of about 25,000
lbf/in.sup.2, and a relatively low sound transmission coefficient
of 28 or less for rigid polyurethane foams with densities of about
2.1 lb/ft.sup.3 to about 2.4 lb/ft.sup.3. Changing the formulation
of polyurethane foams to enhance stiffness and sound protection
typically results in higher costs due to added materials necessary
for fabrication, especially the use of expensive aromatic ring
compounds.
[0009] Conventional high insulation doors suffer from certain
performance limitations. Most high insulation doors used in
residences are filled with foams of thermoplastic or thermoset
organic polymers. These doors have a relatively low u-factor of
less than 0.50. In addition, these doors do not perform well during
extended exposure to fire.
[0010] Current designs of high insulation doors generally require
stiff skins of metal or fiberglass to provide the structural
strength that is typically necessary for residential applications.
Stiff skins are generally more expensive than other aesthetic
surfaces, therefore high insulation doors composed of stiff skins
typically cost more than other residential doors. Moreover, these
doors are lighter in weight than wood doors. Since consumers
correlate increased weight with increased quality and security,
consumers are not drawn to high insulation doors that are lighter
than wood doors. High insulation doors commonly provide
insufficient resistance to sound transmission for use in areas
requiring sound transmission coefficients that exceed about 28, for
example, in light commercial buildings near airports.
[0011] It would be desirable to provide a high performance door
with a gas-entrained cementitious core that is relatively
inexpensive to manufacture, passes positive pressure fire tests,
resists rusting, denting and cracking, and requires relatively low
maintenance. It would also be desirable to provide a method for
manufacturing a high performance door with the above-mentioned
attributes.
SUMMARY OF THE INVENTION
[0012] The high performance doors of the present invention provide
a gas-entrained cementitious core that is relatively inexpensive to
manufacture, passes positive pressure fire tests, resisting
rusting, denting, and cracking, and requires relatively low
maintenance. The methods of the present invention provide a means
of manufacturing the high performance doors of the present
invention with the above-mentioned attributes.
[0013] One aspect of the present invention is a high performance
door comprising a door shell having a generally planar construction
with marginal edges and at least one door skin helping to define an
interior door cavity and a door member disposed within the interior
door cavity. The door member is constructed of a gas-entrained
cementitious material. Preferably, the door member has a
compressive strength of at least 30 lbf/in.sup.2 when measured
using ASTM C-39.
[0014] Another aspect of the present invention is a method for
forming a door member for use in construction with a door. The
method generally comprises providing a form having a generally
planar construction, filling the form with a gas-entrained
cementitious material, green-strength curing the gas-entrained
cementitious material, and removing the cured gas-entrained
cementitious material from the form. The material used to construct
the form does not readily adhere to the gas-entrained cementitious
material. The cured gas-entrained cementitious material provides a
gas-entrained cementitious core for use in conjunction with the
door.
[0015] Yet another aspect of the current invention includes a
method for forming a door member for use in conjunction with a door
that comprises selecting a gas-entrained cementitious material,
casting the gas-entrained cementitious material into a form,
allowing the gas-entrained cementitious material to achieve
green-strength cure, and removing the gas-entrained cementitious
material from the form. The gas-entrained cementitious material
preferably has a flowability of between about 4.825 inches and
about 18 inches when tested using the TT flowability method. The
cured gas-entrained cementitious material provides a gas-entrained
cementitious core for use in conjunction with the door.
[0016] Another aspect of the present invention includes a method
for forming a high performance door. The method is generally
comprised of providing a door shell having a generally planar
construction with marginal edges and at least one door skin helping
to define an interior door cavity, placing the door shell in a
fixture, filling the interior door cavity with a gas-entrained
cementitious material, green-strength curing the gas-entrained
cementitious material, and removing the door shell from the
fixture. The cured gas-entrained cementitious material provides a
gas-entrained cementitious core for use in conjunction with the
door.
[0017] These and other objects of the present invention will become
more apparent from a reading of the specification in conjunction
with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a front elevational view of a high performance
door according to one embodiment of the present invention;
[0019] FIG. 2 illustrates a method for forming a gas-entrained
cementitious core according to one embodiment of the present
invention;
[0020] FIG. 3 illustrates a method for securing a casing over a
door member according to one embodiment of the present
invention;
[0021] FIG. 4 illustrates an aesthetic layer applied to a door
member according to one embodiment of the present invention;
[0022] FIG. 5 is a front elevational view of a high performance
door constructed with a pre-pigmented plastic shell showing a stile
insert for securing two hinge plates and a lock box insert for
engaging a lock box according to one embodiment of the present
invention;
[0023] FIG. 6 is a front elevational view of the high performance
door constructed with a pre-pigmented plastic shell showing two
sets of inserts for securing two hinge plates and the lock box
insert for engaging the lock box according to one embodiment of the
present invention;
[0024] FIG. 7 is an exploded view of a set of inserts for engaging
a hinge plate according to one embodiment of the present
invention;
[0025] FIG. 8 illustrates a method for filling high performance
doors with a gas-entrained cementitious core according to one
embodiment of the present invention; and
[0026] FIG. 9 illustrates a method for removing excess
gas-entrained cementitious material from an interior door cavity
according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0027] The present invention will now be described in detail with
reference being made to the accompanying drawings. Referring to
FIG. 1, door 10 is illustrated. According to the preferred
embodiment illustrated in FIG. 1, door 10 is a hinged entry way
door. It is understood that door 10 refers to, but is not limited
to, hinged patio doors, sliding patio doors, hinged interior doors,
residential fire doors (house-to-garage) with neutral or positive
pressure test ratings of up to 90 minutes, commercial fire doors
with ratings of up to 180 minutes, commercial fire doors with
restricted temperature rise in 30 minutes of less than 450.degree.
F., security-rated doors with ratings between grade 20 and 40
according to ASTM F-476, impact-resistant doors suitable for
meeting high wind velocity building codes, general commercial grade
doors, segmented and unsegmented garage doors and sound
transmission resistant doors. According to the preferred embodiment
illustrated in FIG. 1, door 10 includes door member 12 and door
shell 14. The door member 12 is preferably comprised of a
gas-entrained cementitious core. A gas-entrained cementitious
material is preferably used to construct the gas-entrained
cementitious core. The gas-entrained terms, as used as related
concepts, are discussed in greater detail below. The door shell 14
helps to define interior door cavity 16. The door shell 14 can be
comprised of fiberglass, for example, as disclosed and incorporated
by reference in U.S. Pat. Nos. 4,550,540 and RE 36,240.
[0028] As shown in FIG. 1, door shell 14 includes first door skin
18, second door skin 20, and door frame 22. Door frame 22 includes
a first stile 24 and a second stile 26. Stiles 24 and 26 are
parallel to one another. Stiles 24 and 26 are positioned in a
perpendicular relationship to first rail 28 and second rail 30.
Second rail 30 is parallel to and spaced apart from first rail 28.
First rail 28 and second rail 30 extend between and connect to
stiles 24 and 26. It is understood that first rail 28 may be
connected to stiles 24 and 26 after door member 12 is inserted into
interior door cavity 16. According to FIG. 1, door frame 22 has a
rectangular geometric configuration. However, it is understood that
door frame 22 can be arranged in a variety of geometric
configurations depending upon the desired application. For example,
door frame can have a radiused or arched top typical of "mission
style" architecture. Door 10 can have a thickness of between about
0.5 inches and about 3 inches. Preferably, door 10 has a thickness
of between about 1.25 inches and about 1.85 inches. Door 10 can
have a height of between about 48 inches and about 200 inches. Door
heights of about 150 inches to about 200 inches are preferred for
construction of custom arthitectural door panels. Preferably, door
10 has a height of between about 74 inches and about 96 inches.
Door 10 can have a width of between about 8 inches and about 48
inches. Preferably, door 10 has a width of between about 10 inches
and about 44 inches. Most preferably, door 10 has a width of
between about 30 inches and about 42 inches.
[0029] As shown in FIG. 1, stiles 24 and 26 and rails 28 and 30 are
made of laminated wood. Alternatively, untreated wood can be coated
with a sealant, preferably PERMAX 803, to restrict water efflux
through the wood which could possibly stain stiles 24 and 26 and
rails 28 and 30 and could possibly change the water to cement ratio
in the gas-entrained cementitious material. It is also understood
that unlaminated wood may be utilized to construct stiles 24 and 26
and rails 28 and 30. In addition, it is understood that stiles 24
and 26 and rails 28 and 30 can be made of any other material
capable of blocking the migration of the gas-entrained cementitious
material out of edge faces 32. Stiles 24 and 26 can also be a
hollow channel of pultruded or extruded reinforced plastic, a metal
hollow channel, a partially or totally metal reinforced channel
made of a material other than metal, or a compressed mineral stile.
Moreover, a plurality of nails 34 can be inserted into the interior
edges of the stiles prior to filling the interior door cavity with
the gas-entrained cementitious material. The nails 34 serve to
connect the door frame 22 to the gas-entrained cementitious
core.
[0030] As depicted in FIG. 1, first door skin 18 is secured to a
first side of door frame 22 and second door skin 20 is secured to a
second side of door frame 22. Preferably, first door skin 18 and
second door skin 20 are secured to door frame 22 with adhesive. In
one embodiment of the present invention, door skins 18 and 20 are
constructed of fiberglass and can be secured to door frame 22 with
adhesive or mating surfaces. However, it is understood that door
skins 18 and 20 can include interlocking edges that function to
secure door skins 18 and 20 to door frame 22. Alternatively, an
interlocking skin can be used, instead of first door skin 18 and
second door skin 20. The interlocking door skin fits over the door
frame 22 and the edges of the interlocking door skin mate together
through the use of snap-fits.
[0031] As shown in FIG. 1, reinforcement mat 36 can be placed
within the door frame 22 for additional strength. The reinforcement
mat 36 can be fastened to the inside edges of the door frame 22
using nails 38 or any other fastener means. However, it is
understood that the reinforcement mat 36 can be placed within the
door frame 22 without fasteners, and may be fastened to articles
other than the door frame such as interlocking edges of the skins
or purpose-designed holding fixtures. In this example, the
gas-entrained cementitious material is placed around the
reinforcement mat 36 and secures the reinforcement mat 36 within
the interior door cavity 16 upon curing. The material used to
construct the reinforcement mat 36 can vary depending on the
application. For example, reinforcement mat materials can include
metal mesh, such as chicken wire, grill cloth, aluminum screen,
expanded metal, or chain-link fence; polymeric mesh, such as
ultra-high weight molecular polyethylene; construction fencing;
aramid fiber mat; glass fiber mat (needled, woven, or non-woven);
carbon fiber mat; nylon screen; rubber-coated textiles; and plastic
laminated fibers. In addition, solid metal, textile or polymeric
sheets of smaller dimensions than the door frame 22 can be used as
reinforcement mat materials. The solid material has smaller
dimensions than the door frame 18 so that the gas-entrained
cementitious material is not segmented during pouring and
curing.
[0032] FIG. 1 illustrates that first hinge insert 40, second hinge
insert 42, and lock insert 44 can be inserted into the door shell
14 prior to pouring the gas-entrained cementitious material into
the interior door cavity 16. Hinge inserts 40 and 42 can be
fastened to second stile 26, adhered to either or both first door
skin 18 or second door skin 20, or inserted into pre-defined spaces
in either or both first door skin 18 or second door skin 20. Lock
insert 44 can be fastened to first stile 24, adhered to either or
both first door skin 18 or second door skin 20, or inserted into
pre-defined spaces in either or both first door skin 18 or second
door skin 20. Inserts 40, 42, and 44 can also be inserted after the
gas-entrained cementitious material has been poured, but before it
has cured. First hinge plate 46 and second hinge plate 48 can be
secured to first hinge insert 40 and second hinge insert 42 by
using a screw, nail, or similar fastener. Lock apparatus 50 can be
secured to lock insert 44 by using a screw, nail or similar
fastener.
[0033] The door member 12 can be made of a variety of materials
using a variety of processes depending on the application. For
example, the door member 12 can be constructed of the gas-entrained
cementitious material, preferably a controlled low strength
cementitious material, more preferably an air-modified controlled
low strength cementitious material, and most preferably a foamed
cement slurry.
[0034] Gas-entrained cementitious materials refer to inorganic
materials or mixtures of inorganic materials which sets and
develops strength by a chemical reaction with water by formation of
hydrates, and which entrains more than about 5 volume % gas,
preferably between about 10 and about 80 volume %, more preferably
between about 30 and about 60 volume %, and most preferably between
about 40 and about 55 volume %. It is understood that the gas can
come from a variety of sources including, but not limited to direct
gas injection, microspheres containing gases, porous particles
containing gases, and in-situ chemical reactions or changes in the
state of matter. It is further understood that materials entrained
may not always be in the gaseous phase, particularly when
environmental temperatures to which the article is exposed change
significantly. It is further understood that the gases may migrate
through time and be replaced by other gases or liquids.
[0035] Controlled low strength cementitious material (CLSM), a
subset of gas-entrained cementitious materials, refers to a generic
term for flowable cementitious materials having a self-compacting
property and a strength of less than 1,200 lbf/in.sup.2 (8.27 MPa),
preferably an unconfined ultimate compressive strength of 30-500
lbf/in.sup.2, and most preferably an unconfined compressive
strength of 50-250 lbf/in.sup.2. CLSMs are also commonly referred
to as flowable fill, flow fill, or controlled density fill.
[0036] Air-modified controlled low strength cementitious materials
refer to a CLSM which has entrained in it more than 5 volume % air,
preferably between about 10 to about 80 volume % air, more
preferably between about 30 to about 60 volume % air, and most
preferably about 40 to about 55 volume % air.
[0037] Foamed cement slurries refer to a type of air-modified
controlled low strength cementitious material in which the
cementitious material is any type of hydraulic cement, most
preferably Portland cement, in which air or other gases are
entrained at more than 5 volume % air or other gas, preferably
between about 10 to about 80 volume % air or other gas, more
preferably between about 30 to about 60 volume % air or other gas,
and most preferably between about 40 to about 55 volume % air or
other gas. Portland cement is defined in ASTM C-150 and is a
variety of blended hydraulic cement as defined in ASTM C-595.
[0038] Foamed cement slurries are most preferably utilized to
produce gas-entrained cementitious cores by transferring the foamed
cement slurry into the interior door cavity 16. The foamed cement
slurry is prepared by mixing hydraulic cement, water, and a foaming
agent. Typically, air and water are mixed with the foaming agent to
produce a foaming solution with entrained air. Once the foamed
cement slurry is cured, the entrained air inhibits freeze-thaw
spalling of the gas-entrained cementitious core. Once mixed, the
foamed cement slurry can be transferred into the interior door
cavity 16. Preferred methods for transferring the foamed cement
slurry into the interior door cavity are discussed in more detail
below. Preferably, the water to cement ratio in the foamed cement
slurry is greater than about 38 parts water to about 100 parts
cement by weight. If the ratio falls short of 0.38, the resulting
door member can be unacceptably weak. Additional additives, such as
water reducers, setting accelerators, superplasticizers,
reinforcement fibers, and expanded polystyrene beads, can be added
to the foamed cement slurry to enhance properties, such as flow
rate, curing rate, weight, or rigidity. It should be understood
that reinforcing fibers refer to a fiber or a bundle of fibers
having an aspect ratio greater than 4, which results in one or more
increased mechanical properties when present.
[0039] Water reducers, in general, improve the workability of
cement slurries and reduce the amount of mixing water for a given
workability. Typically this is about 5-15% reduction in water
usage. Water reducers are frequently drawn from the groups
consisting of condensed naphthalene sulfonic acids, salts of
lignosulfonic acids, salts of hydroxycarboxylic acids,
carbohydrates and blends thereof. Superplasticizers, also known as
superfluidizers, super water reducers, and high range water
reducers, are a class of water reducers capable of reducing the
water usage by at least about 30%. While not wanting to be bound by
any one theory, it is believed that superplasticizers break down
the large irregular agglomerates of cement particles by virtue of
deflocculation due to adsorption and electrostatic repulsion, as
well as some steric effects. Superplasticizers are typically drawn
from a group consisting of sulfonated melamine-formaldehyde
condensates, sulfonated naphthalene-formaldehyde condensates,
modified lignosulfonates, sulfonic acid esters, polyacrylates,
polystyrene sulfonates, and blends thereof.
[0040] Many cements that are suitable for use in the present
invention contain additives. These additives can include
cementitious and pozzolanic additives. Cementitious additives refer
to an inorganic material or mixture of inorganic materials which
forms or assists to form cementitious materials which develops
strength by chemical reaction with water by formation of hydrates.
Cementitious additives are generally rich in silica and alumina.
According to ASTM C-539-94, pozzolanic additives refer to siliceous
or alumino-siliceous material which in itself possesses little or
no cementitious value, but which when in finely divided form and in
the presence of moisture will chemically react with alkali and
alkaline earth hydroxides at ordinary temperatures to form or
assist in forming compounds possessing cementitious properties.
Examples of pozzolanic additives can include Class C fly ash from
burning lignite coal, Class F fly ash from burning bituminous coal,
pulverized-fuel fly ash, condensed silica fume, metakaolin, rubber
ash, and glass cullet. Additives found in cement are particularly
useful in increasing the mass of the resulting door member.
[0041] Insulating gases can replace entrained air to provide
greater insulation. These gases include molecules that generally
have a higher atomic mass than air. Possible examples include
halocarbons and hydrohalocarbons, such as HCFC-22, HFC-134a,
HFC-245fa, HFC-365mfc; noble gases, such as argon, xenon, and
krypton; sulfur hexafluoride; hydrocarbons, such as pentane; and
mixtures thereof. The process of introducing the insulating gas
into the foamed cement slurry is discussed below.
[0042] Door members 12 can be formed without the use of a door
shell 14. As shown in the embodiment depicted in FIG. 2, slabs of
concrete or cement that have relatively low slump values and
relatively low flow rates can be cast. Suitable foamed cement
slurries for this purpose include those that have a flowability of
about 4.825 inches to about 18 inches using the TT flowability
method. The TT flowability method includes preparing a close-ended
box from pressure-treated Southern Yellow Pine that includes a
reservoir. The box is treated with polyvinylidene chloride,
preferably PERMAX 803, for sealing purposes. The box is preferably
at least 26 inches long. The reservoir is preferably a 6
inches.times.6 inches.times.6 inches cube with a non-porous slide
gate leading to the flow channel. The box is placed on a level
surface. The foamed cement slurry to be tested for flowability is
poured into the reservoir, and screed off even with the 6 inch high
mark. The slide gate is opened with any adhering foamed cement
slurry scraped off into the reservoir. The foamed cement slurry is
allowed to flow into the channel. The furthest distance of flow
from the slide gate is measured after 1.0 minute.
[0043] The slabs are formed by pouring a suitable foamed cement
slurry 60 with a relatively low slump value and relatively low flow
rate through nozzle 62 into a form 64, preferably an open-faced
form. The open-faced form is preferably placed on a horizontal belt
66 before the foamed cement slurry 60 is poured. Mechanical
spreader 68 is preferably used to distribute the foamed cement
slurry in the open-faced form and to prepare the cured foamed
cement slurry for the door frame. Other suitable devices to
distribute and prepare the foamed cement slurry include screes and
embossment units. Once the foamed cement slurry is cured, the
resulting door member is released from the open-faced form. The
form can be constructed of ultrahigh molecular weight polyethylene,
high density polyethylene, polypropylene, polycarbonate,
polyvinylidene chloride or any other material that does not readily
adhere to the foamed cement slurry. The Hardie Plank machine,
available from James Hardie Company of Australia can be used to
form continuous casting slabs of polymer cement board. In addition,
the Cemplank machine or the Cembord machine, both available from
Cemplank, Inc. of Blandon Pa. can be used to form continuous
casting slabs of polymer cement board.
[0044] Door members that are cast in the open-faced form can be
secured to a door shell through adhesives. Securing means are
understood to include, but be limited to, fasteners, adhesives,
snap-fits, plastic or metal welding, interlocks, and pressure fit
devices.
[0045] For example, as illustrated in FIG. 3, casing 72 can be
secured over the door member 74. Casings are understood to mean
vessels for receiving core materials where marginal edges are
present or may be formed by temporary external means and the second
skin surface is either attached on at least once side to the
marginal edge or may be connected in a subsequent process step.
Casings are understood to include, but are not limited to,
multi-sided pans with lids, tubes, tubes that conform to temporary
external fixtures, bags, cassettes with multiple sides that fold,
fold-over or that are pre-folded and secured with a top flap that
is secured in a subsequent process step.
[0046] As illustrated in FIG. 4, an aesthetic layer 78 can be
applied to the door member 80. Examples of a specific type of
aesthetic layers, wood-like aesthetic surface layers, can include
wood veneers, decorative films that simulate wood finishes,
transcribed pigment layers, polyvinylidene chloride coated wood and
organic polymer coating. An example of a decorative film that
simulates a wood finish is an extruded sheet containing dyes that
liquefy at different temperatures, as disclosed in U.S. Pat. No.
5,866,054. An example of a transcribed pigment layer is FINAL
FINISH, a product available from Immersion Graphics, Inc. of
Columbus, Ga. It is understood that prior to applying the wood-like
aesthetic surface layer, a finish sanding or other smoothing
process can be utilized to minimize minor imperfection on the
surface of the door member. A wood-like texture can be molded into
the door member. Many processes exist to produce wood-like
textures. For example, a silicone rubber or polymer film master can
be constructed from a model door skin. In addition, the following
processes can be utilized: an acid-etched steel master can be
constructed from a photoresist, nickel chemical vapor deposition
can be utilized, and hand or machine engraved masters of wood,
metal, ceramic, or polymer can be used.
[0047] Moreover, a wood-grained decorative fiberglass tissue,
available from Lance Brown Import-Export can be molded into the
door member. Alternatively, the wood-like texture can be a
stainless steel foil bag, available from McMaster-Carr. The
stainless steel foil bag is properly shaped to have door-like
edges. In addition, an insertable door member can be CNC machined
and coated with a topcoat, primer or sealer.
[0048] Another embodiment of the present invention is illustrated
in FIG. 5 as having a pre-pigmented plastic door shell 84.
Preferably, the pre-pigmented plastic door shell 84 is fabricated
using a blow molding method. However, it is understood that other
fabrication processes can be used depending on the application.
These fabrication processes can include rotomolding, sheet
extruding, injection molding or thermoforming. A particularly
useful sheet extruding method includes forming a biaxially oriented
sheet, trimming and notching the biaxially oriented sheet, and
fastening a pre-formed door member to the biaxially oriented sheet
by using adhesives or ultrasonic welding. A particularly useful
injection molding process includes injection molding sections of
the door frame and fastening the sections together to form the door
frame. Examples of pre-pigmented plastics include polystyrene,
polyvinyl chloride, polyethylene terphthalate, polyolefins, nylon,
ABS, ABS-(ABS-glass fiber)-ABS composites, long fiber
thermoplastics, reinforced plastics, and blends of these plastics.
Preferably, ABS is used. Pre-pigmenting gives a uniform surface
color and painting is not necessary.
[0049] An elongated insert 86 can be placed along inner edge 88
through a hole 90, as illustrated in FIG. 5. Elongated insert 86
can be up to the height of the pre-pigmented plastic door shell 84.
First hinge plate 92 and second hinge plate 94 can be secured to
elongated insert 86 by using a screw, nail, or similar fastener.
Lock apparatus 96 can be secured to lock insert 98 by using a
screw, nail or similar fastener.
[0050] A first set of hollow inserts 102 and a second set of hollow
inserts 104, as illustrated in FIGS. 6 and 7, can be inserted into
pre-pigmented plastic door shell 84 after the door member is placed
within the interior door cavity or the foamed cement slurry cures
within the interior door cavity. As illustrated in FIG. 7, the
inserts 102 and 104 screw into the door member and are held in
place by screw threads 78. First hinge plate 92 and second hinge
plate 94 can be secured to inserts 102 and 104 by using a screw,
nail or similar fastener. Two inserts are shown for simplicity. The
number and spacing of the inserts will be dependent on the style of
the hinge plate to be affixed thereto.
[0051] FIG. 8 depicts a preferred method of filling the interior
door cavity with the foamed cement slurry and curing the foamed
cement slurry to produce the gas-entrained cementitious core. It is
understood that a flexible, non-ceramic compound can be introduced
into the interior door cavity before filling to enhance the
flexibility of the resulting high performance door. According to
FIG. 8, a bank 110 of door shells are placed on platform 112 with
an orientation such that the rails are parallel with the ground.
Preferably, the first rail includes a pour hole 114. It is
understood, however, that the door shells may be placed in any
orientation conducive to introducing the foamed cement slurry into
interior door cavity. These orientations include, but are not
limited to, having stiles parallel with the ground and having door
skins parallel with the ground. After being placed on platform 112,
the series 110 of door shells are clamped into fixture 116, using a
range of pressure between about 0.1 lbf/in.sup.2 and about 20
lbf/in.sup.2. Preferably, fixture 116 uses a range of pressure of
between about 0.5 lbf/in.sup.2 and about 2.0 lbf/in.sup.2. Suitable
fixtures for use with the present invention include a platen press,
a bladder press, a pod press, a lamination line, and an edge clamp.
Preferably, fixture 116 is comprised of a platen press that has a
platens 118 and 120. The temperature of the platens can be between
about -2.degree. C. and about 95.degree. C. Preferably, the
temperature of the platens is between about 20.degree. C. and about
30.degree. C.
[0052] Nozzle 122 is preferably inserted within the interior door
cavity through pour hole 114. Preferably a plurality of vent holes
and grooves are included in the bottom end rail to prevent
significant pressurization during pouring of the foamed cement
slurry. It is also understood that no end rail is required during
pouring and may be added later or not at all. Nozzle 122 delivers
the foamed cement slurry into interior door cavity. The foamed
cement slurry can be transferred into interior door cavity
incrementally, using between 1 and 5 increments. Preferably, 1 to 3
increments are used to fill interior door cavity 16 with the foamed
cement slurry. Most preferably, 1 increment is used to fill
interior door cavity 16.
[0053] Alternatively, as illustrated in FIG. 9, the filling process
can include placing door shell 128 such that the door skin(s) are
generally parallel to the ground. After the interior door cavity is
filled with the foamed cement slurry, a set of rollers 130 can be
run over one of the door skins 132 to remove excess gas-entrained
cementitious material 134 from the interior door cavity.
[0054] If the foamed cement slurry includes an insulating gas, the
following procedure is preferably utilized. The foaming agent is
pre-blended in an evacuated pressure vessel. The insulating gas is
introduced into the evacuated pressure vessel. The other
ingredients, which can include cement, water, setting accelerator,
and water reducer, are mixed in a colloidal mixer and a ribbon
mixer that are enclosed and evacuated to limit the presence of air.
Once the other ingredients are sufficiently mixed in the evacuated
ribbon mixer, the pre-blended foaming agent/insulating gas mixture
is introduced.
[0055] The door skins are preferably secured to the walls of a
holding fixture by evacuating the holding fixture. The door frame
preferably has a first rail with a pour hole. An air lock is placed
at the pour hole, and the interior door cavity is evacuated after
the holding fixture evacuation. The vacuum pressure between the
fixture vacuum holding the skin to the holding fixture walls is at
least about 1 mm Hg greater than the vacuum of the interior door
cavity. The foamed cement slurry, containing the entrained
insulating gas is then pumped into the interior door cavity through
the air lock, minimizing the contamination of the slurry with
ambient air.
[0056] The pore size of the entrained insulating gas or air can be
influenced. During curing, the fixture can be warmed in a
convective, dialectric, or microwave oven until the cementitious
reaction has allowed the cement to form a structurally stable cell
wall around entrained gas and/or air bubbles. The residence time in
the oven necessary to achieve a stable cell wall depends on the
formulation of the foamed cement slurry, including the cement and
setting accelerator used, and the oven temperature. For air, the
oven temperature can range from about 1.degree. C. to about
70.degree. C. above ambient, preferably about 10.degree. C. to
about 40.degree. C., and most preferably about 20.degree. C. to
about 35.degree. C. For other gases, the range can vary depending
on the mass and the molecular weight of the insulating gas.
[0057] During the curing process, a hydration reaction occurs
within the foamed cement slurry. This reaction increases the amount
of heat in the interior door cavity. In a typical bank 110 of 12
doors placed within the fixture, the foamed cement slurry
temperature in the interior door cavity may reach about 60.degree.
C. above ambient within about six hours of curing. After the
structurally stable cell wall is achieved, cooling may be added to
reduce excess pressure from the expanded entrained gas.
Conventional heat exchangers can be used to conserve energy during
this process.
[0058] Air vibrators 124 and 126 can be attached to fixture 116 to
induce improved flow and consolidation of the foamed cement slurry
so as to avoid voids caused by bridging of the foamed cement
slurry. Air vibrators 124 and 126 may also assist in decreasing the
viscosity of the flow in foamed cement slurries that include
thixotropic agents. Preferably, a US13 air vibrator, available from
Global Manufacturing of Little Rock, Ark. can be employed.
Preferably, the US13 air vibrator is employed for between about 2
seconds to about 30 seconds. Most preferably, the US13 air vibrator
is employed for between about 5 seconds to about 10 seconds, during
each incremental addition of the foamed cement slurry.
[0059] If the door skins are constructed of fiberglass and the
tensile strength of the skins is less than about
1.0.times.10.sup.6lbf/in.sup.2, it is preferable to apply a vacuum
from the fixture 116 to the outer surface of the door skin(s) in
order to hold the door skins flat during poring. The fixture draws
about 5 psi to about 20 psi vacuum. The fixture surfaces preferably
have grooves to allow air trapped in the vacuum ports to escape out
of the edges of the fixture.
[0060] Once interior door cavity is filled with the foamed cement
slurry, a cap can be secured to the first rail. The filled door
shell may be capped with a top rail of thermoplastic polymer,
thermoset polymer, or metal. Alternatively, the cap can be
constructed of trimmable wood, optionally coated with a waterproof
coating, preferably PERMAX 803, produced by Noveon, Inc.,
Cleveland, Ohio.
[0061] Once the interior door cavity is filled with the foamed
cement slurry, the foamed cement slurry is allowed to cure in
fixture 116. The foamed cement slurry reaches an initial set point
once it either resists slumping, or passes through an exothermic
maximum generated during the hydration reaction, whichever comes
first. After reaching the initial set point, the foamed cement
slurry further cures to reach a final set point in which the door
can be moved without damaging the door member. Depending on the
foamed cement slurry formulation, the initial set point and the
final set point vary. In Example 3 below, exothermic temperature
profiles are provided for two different formulations, showing the
variations in the initial and final set points. Using ASTM method
C-403, the door can be removed from the fixtures when the
penetrometer indicates the foamed cement slurry of Example 1
achieves a strength about 70 lbf/in.sup.2. It is also understood
that these compressive strengths are not identical with compressive
strength measurements obtained by ASTM C-39 (results described
later).
[0062] Depending on the formulation, the foamed cement slurry can
be cured in the fixture for a period of between about 1 minute and
about 48 hours. Preferably, the cure time in the fixture is between
about 5 minutes and about 24 hours. Most preferably, the cure time
in the fixture is between 10 minutes and about 24 hours. The
process of curing the slurry until the door can be removed from the
fixture without damage is referred to as green-strength curing.
[0063] To reduce curing time, a rapid-cure setting accelerator can
be added to the foamed cement slurry. The rapid-cure setting
accelerator is preferably injected into the stream of foamed cement
slurry at the end of nozzle 122 with a discharge tube. The
discharge tube preferably includes a check valve to minimize back
flow of the foamed cement slurry into the discharge tube. The
typical rapid-cure setting accelerator has a basic pH of between
about 11 and about 13. General examples include aluminum based
accelerators, modified sodium silicate based accelerators, liquid
alkali based accelerators, and alkali-free accelerators based on
calcium oxide. These accelerators are discussed in U.S. Pat. Nos.
6,221,151 and 6,025,404, which are incorporated by reference. The
cure time is reduced to between about 2 minutes to about 10 minutes
by using the rapid-cure setting accelerator.
[0064] After emerging from the fixture, the foamed cement slurry
can be further cured to achieve increased strength and final
setting. The cure time after emerging from the fixture can be from
about 0 days to about 100 days, preferably about 3 to about 28
days, and most preferably about 10 days to about 28 days. The
typical range of compressive strengths measured using ASTM C-39 of
a door member constructed of the foamed cement slurry is about 58
lbf/in.sup.2 to about 75 lbf/in.sup.2.
[0065] Having generally described the present invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only and are not intended to be limiting unless otherwise
specified.
EXAMPLE 1 AND COMPARATIVE CHART A
[0066] A preferred foamed cement slurry of the present invention
which is capable of being cured for use as a door member comprises
the following:
1 TABLE 1 Component As-Is/Dry Weight % Hydraulic cement 61.43%
Water 26.30% Foaming solution 9.22% Water reducer 0.01% Setting
Accelerator 0.04% Reinforcement fibers 0.18% Expanded polystyrene
beads 2.82%
[0067] The preferable hydraulic cement is Portland Cement Type III,
produced by Lone-Star Industries, Inc. of Indianapolis, Ind. The
preferable water is tap water. The foaming solution is preferably
comprised of 1 part foaming agent and 40 parts water. The
preferable foaming agent is MEARLCRETE foam liquid concentrate,
produced by Cellular Concrete LLC of Roselle Park, N.J. The
preferable water reducer is RHEOBUILD 100, produced by Master
Builders Technologies of Cleveland, Ohio. The preferable setting
accelerator is POZZOLITH NC574 of Master Builders Technologies of
Cleveland, Ohio. The preferable reinforcement fibers are STEALTH
{fraction (3/4)} inch long polypropylene fibers, produced by the
Fibermesh Division of Synthetic Industries of Chattanooga, Tenn.
The preferable nominal diameter of the expanded polystyrene beads
is {fraction (1/4)} inch and are available from the Cellofoam
Company of Conyers, Ga.
[0068] A preferred method of mixing the ingredients of the foamed
cement slurry comprises the following steps. The water, hydraulic
cement, setting accelerator, and reinforcement fibers are added to
a colloidal mixer supplied by Chem Grout of LaGrange Park, Ill.
Preferably, the four ingredients are added to the colloidal mixer
in that order. Upon mixing the ingredients for at least 45 seconds
(to ensure substantial mixing of the hydraulic cement and the
water), the water reducer is added to the colloidal mixer. By
waiting at least 45 seconds to add the water reducer, the
effectiveness of the water reducer is greatly enhanced. After
mixing the water reducer with the other four ingredients, the
contents of the colloidal mixer is transferred to a ribbon mixer
preferably supplied by Chem Grout of LaGrange Park, Ill. In a
foaming agent mixer, the foaming agent, water, and air are mixed to
form the foaming solution. Preferably, the foaming solution is
added to the ribbon mixer, with the addition of the expanded
polystyrene beads following. The ribbon mixer is preferably
modified to include t-bars to assist in blending the contents of
the ribbon mixer.
[0069] A preferred method of transferring and curing the foamed
cement slurry comprises the following steps. Before the interior
door cavity is filled with the foamed cement slurry, the door shell
is clamped into a platen press using a force of about 0.5
lbf/in.sup.2 to about 2.0 lbf/in.sup.2. The temperature of the
platens is in the range of about 20.degree. C. to about 30.degree.
C. Once the contents of the ribbon mixer are substantially blended,
a Moino pump is preferably used to pump the foamed cement slurry
into the interior door cavity. The Moino pump does not excessively
compress air bubbles entrained in the foamed cement slurry so as to
destroy the foaming action of the foaming solution. The foamed
cement slurry is transferred into the door shell in 1 to 5
increments, preferably 1 to 3 increments, and most preferably 1
increment until the interior door cavity is filled. The filled door
is allowed to cure in the platen press until the foamed cement
slurry does not slump. The cure time in the press fixture is
preferably from about 6 hours to about 10 hours.
[0070] It is also understood and preferable to transfer foamed
cement slurry and fill the interior door cavity by means of a
gravity feed system. In this system, the contents of the ribbon
blender are poured under the force of gravity into a hopper. The
hopper is mechanically positioned over the interior door cavity.
The foamed cement slurry is allowed to flow from the hopper into
the interior door cavity. The advantage of this system is cost
reduction by limiting the destruction of bubbles passing through
the compressive phase of the pump.
[0071] Various foaming agents were tested using the foamed cement
slurry of Example 1 and substituting various foaming agents. One
test included pouring the foamed cement slurry into an about 10
foot high by about 4.5 inch diameter column. The slurry was leveled
off flush with the top of the column. The most preferable foams
would allow the foamed cement slurry to avoid shrinking or
permanently expand by more than about 2 millimeters during setting
so that the cement column was actually higher than the top of the
column when observed after about 8 hours of curing.
[0072] Another test includes foaming various foaming agents with
air in a five gallon HDPE pail container. Preferably, a "Junior"
foam generator supplied by EAB Associates, Altrincham, United
Kingdom is used to foam the foaming agent. An 85 gram plate load
with a diameter of about 5.25 inches is placed on top of the foam.
If the load remains visible above the foam after about one hour,
otherwise referred to as persistence time, the foam is suitable for
the manufacture of at least about eight foot high doors.
[0073] The following table includes the test results for various
foaming agents:
2CHART A Foaming Column Persistence Foaming agent agent type
expansion time (hrs) EABASSOC Synthetic N/A 0.5 PS 1262
Protein-based Shrinkage 3 Mearlcrete Protein-based Expansion >3
AFTC101251 Synthetic Expansion >3 RHEOCELL 15 Synthetic N/A
0.2
[0074] It should be understood that the column expansion was not
measured for EABASSOC and RHEOCELL 15 since the persistence time
was too short to accommodate such a measurement.
[0075] EABASSOC is available from EAB Associates of Altrincham,
United Kingdom. PS 1262 foaming agent is available from Master
Builders Technologies of Cleveland, Ohio. Mearlcrete is available
from Cellular Concrete L.L.C. of Roselle Park, N.J. AFTC101251 is
available from Applied Foam Tech Corporation of Harleysville, Pa.
RHEOCELL 15 is available from Master Builders Tech.
[0076] The synthetic foaming agents are suitable for use with
superplasticizers to increase flowability of the foamed cement
slurry. A preferred combination of foaming agent and
superplasticizer is RHEOCELL 30 and RHEOBUILD HRWR 3000 FC.
EXAMPLE 2
[0077] Example 2 is a low cost variation of the foamed cement
slurry in Example 1. To reduce the cost of the foamed cement
slurry, a foaming solution is substituted for expanded polystyrene
beads. The foamed cement slurry of Example 2 comprises the
following:
3 TABLE 2 Component As-Is/Dry Weight % Hydraulic cement 59.20%
Water 25.33% Foaming solution 15.24% Water reducer 0.01% Setting
Accelerator 0.04% Reinforcement fibers 0.18%
[0078] The preferable ingredients are the same as the preferred
ingredients of Example 1. The preferred mixing process for the low
cost variation of the foamed cement slurry is similar to the mixing
process of Example 1, except that expanded polystyrene beads are
not added to the ribbon mixer. The preferred method of transferring
and curing the low cost variation of the foamed cement slurry is
similar to the transferring and curing process of Example 1, except
that the preferable curing time in the press fixture is between
about 16 hours and about 24 hours. This example passes both ASTM
2074-00 and BSI 476/22 fire tests. Comparative Chart B gives
density gradient data for examples 1 an 2.
4 CHART B Height From Bottom Of Density (lb/in.sup.3) Density
(lb/in.sup.3) Column Example 2 Example 1 0 ft 23.24 24.32 1 23.31
23.58 2 22.55 24.35 3 22.80 24.73 4 22.67 24.03 5 22.69 24.16 6
22.83 23.13 7 22.30 22.65 8 21.73 22.29 9 21.32 21.66
EXAMPLE 3 AND COMPARATIVE CHART C
[0079] A preferred foamed cement slurry of the present invention
includes Portland Cement Type I hydraulic cement. Portland Cement
Type I is a low cost alternative to Portland Cement Type III since
Type I is not as finely ground as Type III. The preferred cement
slurry of example 3 is comprised of:
5 TABLE 3 Component As-Is/Dry Weight % Hydraulic cement 62.04%
Water 26.88% Foaming agent 7.99% Water reducer 0.02% Accelerator
0.04% Polypropylene fibers 0.18% Expanded polystyrene beads
2.85%
[0080] The preferable ingredients are the same as the preferred
ingredients of Example 1, except that the preferred hydraulic
cement is Portland Cement Type I produced by Lone-Star Industries,
Inc. of Indianapolis, Ind. The preferred mixing process for the
foamed cement slurry of Example 3 is similar to the mixing process
of Example 1. The preferred method of transferring and curing the
foamed cement slurry of Example 3 is similar to the transferring
and curing process of Example 1, except that the preferable curing
time in the press fixture is between about 16 hours and about 24
hours. It is understood that this curing process can be quickened
by increasing the temperature of the cure above ambient. At a cure
temperature of about 30.degree. F. above ambient temperature, the
cure times are reduced by 50%.
[0081] Portland Cement Type III is a finer grained cement than Type
I. As a result, the foamed cement slurry using Type III, achieves
its final set point about two hours earlier than the foamed cement
slurry of this using Type I. The exothermic temperature profiles of
the two foamed cement slurries confirm these results:
6CHART C Example 1 Example 3 Time (min.) (using Type III) (.degree.
F.) (using Type I) (.degree. F.) 0 67.6 65 30 69.4 68 60 70.7 70.2
90 72.3 72.6 120 74.1 74.6 (Initial set) 150 76.6 78.2 (Initial
set) 180 79.8 82.2 210 84 87.4 240 89.6 94.8 270 98.6 103.2 (Final
set) 300 110.8 112.8 330 117.3 117.6 360 118.3 119.6 390 119.3
120.2 (Final set) 420 118.9 119.6 450 117.3 118.6
EXAMPLE 4
[0082] A preferred foamed cement slurry of the present invention
which is capable of being cured for use as an door member and is
particularly suitable as a fire resistant door comprises the
following:
7 TABLE 4 Component As-Is/Dry Weight % Hydraulic cement 65.59%
Water 28.67% Foaming solution 3.95% Water reducer 0.01% Accelerator
0.04% Polypropylene fibers 0.33% Expanded polystyrene beads
1.42%
[0083] The preferable ingredients are the same as the preferred
ingredients of Example 3, except that the preferable foaming agent
is RHEOCELL 15, available from Master Builders Technologies, of
Cleveland, Ohio and the preferable water reducer is RHEOBUILD HRWR
3000 FC, available from Master Builders Technologies, of Cleveland,
Ohio. The preferred mixing process for the foamed cement slurry of
Example 4 is similar to the mixing process of Example 1. The
preferred method of transferring and curing the foamed cement
slurry of Example 4 is similar to the transferring and curing
process of Example 1, except that the preferable curing time in the
press fixture is between about 16 hours and about 24 hours.
[0084] The fire resistant door using the preferred foamed cement
slurry of example 4 passes the 20 minute ASTM 2074-00 positive
pressure fire test and the 30 minute BSI 476/22 positive fire
test.
EXAMPLE 5
[0085] A preferred foamed cement slurry of the present invention
which is capable of being cured for use as an door member and has a
relatively low slump value and a relatively low flow rate:
8 TABLE 5 Component As-Is/Dry Weight % Hydraulic cement 61.43%
Water 26.30% Foaming solution 9.22% Water reducer 0.01% Setting
accelerator 0.04% Polypropylene fibers 0.18% Expanded polystyrene
beads 2.82%
[0086] The preferred ingredients are the same as the preferred
ingredients of Example 1. The preferred mixing process for the
foamed cement slurry of Example 5 is similar to the mixing process
for Example 1.
[0087] The foamed cement slurry is suitable for continuously
casting slabs on a horizontal belt into an open-faced form, using a
hydrostatic head pressure feed of at least about 6 feet. A
mechanical spreader, a scree, or an embossment unit is preferably
used to distribute the foamed cement slurry in the form and to
prepare the cured foamed cement slurry for the door frame. The
preferred curing time in the open-faced form is between about 8
hours and about 16 hours.
EXAMPLE 6
[0088] A preferred high performance door of the present invention
is constructed to inhibit the transfer of heat through the door
member during a fire. The preferred high performance door according
to this example limits the temperature of the door surface not
exposed to the fire to 250.degree. C. after 30 minutes, using the
ASTM E-152 standard. The door shell is constructed of SAE 1010
carbon steel or similar material.
[0089] The door member is comprised of a cured foamed cement
slurry. The foamed cement slurry is comprised of:
9 TABLE 6 Component As-Is/Dry Weight % Hydraulic cement 65.14%
Water 24.43% Foaming solution 10.07% Water reducer <0.01%
Setting accelerator 0.02% Polypropylene fibers 0.33%
[0090] The preferable ingredients are the same as the preferred
ingredients of Example 3. The preferred mixing process for the
foamed cement slurry of Example 6 is similar to the mixing process
of Example 2.
[0091] The foamed cement slurry is transferred into a form, which
is sized similar to the door shell. The form is preferably made of
an ultrahigh molecular weight polyethylene material. The form may
have embossment patterns to match patterns present on a door shell.
The foamed cement slurry is transferred into the form in 1 to 5
increments, preferably 1 to 3 increments, and most preferably 1
increment until the form is filled.
[0092] After curing the foamed cement slurry in the form from about
10 days to about 28 days, the cured foamed cement core, or door
member, is stripped from the form. An adhesive is applied to the
door member sufficient to hold the door member to the interior of
the steel door shell. Moreover, sufficient adhesive is applied to
the door so that it survives code-required slam durability tests
(ANSI/ISDI 105). A typical test requires that the door last for
1,000,000 slam cycles and the adhesive should be applied to at
least 70% of the surface area of the insulating core member.
Preferably, the adhesive is an elastomeric latex adhesive, such as
PPG TRIMBOND T7850, available from PPG Industries. Other adhesives
include hot melt polyurethane, epoxy, and structural silicon
caulk.
EXAMPLE 7
[0093] A preferred method of producing a high performance door of
the present invention includes transferring a rapid-cure setting
accelerator into the interior door cavity to greatly reduce the
curing time. The foamed cement slurries of Examples 1-6 can be used
in the rapid-cure method of Example 7 if the setting accelerator of
Examples 1-6 is substituted with the rapid-cure setting
accelerator. The preferable rapid-cure setting accelerator is
shotcrete, otherwise referred to as gunite, available from various
suppliers.
[0094] The preferred mixing process for the rapid-cure method is
similar to the mixing processes of Examples 1-6, except that the
setting accelerator is not added to the colloidal mixer.
[0095] A preferred method of transferring and curing the foamed
cement slurry comprises the following steps. Once the contents of
the ribbon mixer are substantially blended, a Moino pump is
preferably used to pump the foamed cement slurry into the interior
door cavity or the open-faced form. The Moino pump does not
excessively compress air bubbles entrained in the foamed cement
slurry so as to destroy the foaming action of the foaming solution.
The rapid-cure setting accelerator is preferably injected into the
foamed cement slurry as the slurry exits the Moino pump at a nozzle
head. Preferably, a discharge tube is used to inject the rapid-cure
setting accelerator. To avoid back flow of the foamed cement slurry
into the discharge tube, the end of the discharge tube preferably
includes a check valve. The set time is preferably from about 2
minutes to about 10 minutes. COMPARATIVE EXAMPLE 8
[0096] In foamed cement slurry formulations containing expanded
polystyrene beads, an optimum amount of foaming solution should be
added to reduce destruction of foam bubbles entrained in the foamed
cement slurry. The following table discloses a foamed cement slurry
containing 37 parts by volume expanded polystyrene beads to 63
parts by volume foaming solution:
10 TABLE 7 Component As-Is/Dry Weight % Hydraulic cement 61.43%
Water 26.29% Foaming solution 9.22% Water reducer 0.01% Setting
accelerator 0.04% Polypropylene fibers 0.18% Expanded polystyrene
beads 2.82%
[0097] If the formulation in Table 7 is used, an additional 22.8
parts by volume of foaming solution should be added relative to the
volume of expanded polystyrene beads to reach the optimum level of
foaming solution.
[0098] The following table discloses a foamed cement slurry
containing 18 parts by volume expanded polystyrene beads to 82
parts by volume foaming solution:
11 TABLE 8 Component As-Is/Dry Weight % Hydraulic cement 61.02%
Water 26.12% Foaming solution 11.26% Water reducer 0.01% Setting
accelerator 0.04% Polypropylene fibers 0.18% Expanded polystyrene
beads 1.37%
[0099] If the formulation in Table 8 is used, an additional 14
parts by volume of foaming solution should be added relative to the
volume of expanded polystyrene beads to reach the optimum level of
foaming solution.
[0100] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *