WO2003070456A1

WO2003070456A1 - Large high density foam glass tile

Info

Publication number: WO2003070456A1
Application number: PCT/US2003/004005
Authority: WO
Inventors: Pedro M. Buarque De Macedo; Hamid Hojaji
Original assignee: Macedo Pedro B
Priority date: 2002-02-15
Filing date: 2003-02-10
Publication date: 2003-08-28
Also published as: AU2003224611A1; US20060075704A1; JP5249269B2; CA2476299A1; CN1642730A; DE60319957D1; EP1474290A4; MXPA04007759A; JP2010174616A; EP1923210A2; EP1923210A3; US8197932B2; DE60319957T2; US20030145534A1; US6964809B2; JP2005521615A; US20040123535A1; EP1474290B1; ATE390275T1; AU2003224611B2

Abstract

A large, high density foam glass tile which can be used as a facade on both exterior and interior building walls. The foam glass tile can also be used with other materials to form a panel or a composite. The present invention may be used on the critical surfaces of buildings at high risk for terrorist attacks, in combination with cement, steel or other high strength building materials. The present invention may also be used in surfaces of typical buildings. The present invention has the advantage of absorbing a substantial portion of a shock wave caused by an explosion. The present invention also has the advantage of being more resistant to earthquakes.

Description

LARGE HIGH DENSITY FOAM GLASS TILE

FIELD OF THE INVENTION

[ OOOl] The present invention relates generally to a building material to be

used in building construction. More particularly, the present invention relates to

large high density foam glass tiles to be used on both interior and exterior facades

of buildings. Even more particularly, the present invention relates to large high

density foam glass tiles to be used on interior and exterior facades of buildings

which enable such buildings to have a greater resistance to explosions.

[ 0002] The present invention further relates to a composite of panels made

from such tiles, and more particularly, to a blast energy absorbing structural

laminate and a method of making the same by bonding layers of foamed glass or foamed siliceous materials with structural inorganic cementaceous materials,

polymeric materials, metals and fibers which can be optionally used in laminates.

BACKGROUND OF THE INVENTION

[ 0003] Over the past decades, there have been a significant number of

terrorists attacks on government buildings owned by the United States and other

countries both outside of the United States and within. For example, in 1993,

terrorists exploded a car bomb inside the garage of the World Trade Center located

in New York City, resulting in loss of life and significant property damage. Since then, in 1995, other extremists exploded a truck outside of the Federal Building located in Oklahoma City, Oklahoma also resulting in significant loss of life and

property damage. In 1998, the United States embassies in Nairobi and Dar Es

Salaam were also subject to terrorists attacks by car bombs, each of which resulted

in significant loss of life and property damages. Most recently, the tragic events at

the World Trade Center in New York City and the Pentagon in Virginia has further

emphasize the long felt need to develop and manufacture building materials which

are able to withstand the shock wave from car bomb explosions and other similar terrorist attacks.

[ 0004] While the concept of using foam glass as a construction material is

well known in the prior art, generally such foam glass has been used as a high

temperature insulator and thus seeks to minimize its density and weight and is not suitable for absorbing sufficient energy from a shock wave from unexpected

explosions or to resist an earthquake. The shortcomings in such conventional foam

glass as relevant to this long standing problem is now described.

[ 0005] For example, Pittsburgh Corning Corporation ("PCC") of Pittsburgh,

Pennsylvania has developed and marketed a product known as Foam Glas®

Insulation Systems, which is described in U.S. Patent Nos. 3,959,541, 4,119,422, 4,198,224, 4,571,321 and 4,623,585. Because the focus of these developments are

directed to making a foam insulating material, the Foam Glas® Insulation Systems tile commercially sold by PCC is relatively light, weighing 9.5 lbs. Furthermore,

since the purpose of this tile is to be used as thermal insulation, it lacks surface strength, and can be dented very easily. Because the Foam Glas® Insulation

Systems tile is of relatively low density, e.g., 9.5 lb./cu. ft., such tiles will easily

break when exerted to forces typically asserted on exterior walls to a building or

other structure. Thus, such tiles are not suitable to be used as tiling for an exterior

wall. Similarly, this foam, when exposed to a shock wave from an explosion will

absorb very little of the shock waves energy when it implodes. A shock wave is a measure associated with explosions which is easily understood by those skilled in

the art as being a pressure front resulting from an explosion.

[ 0006] Others have also attempted to use foam glass tiles as the outer skin-

surface of buildings. For example, U.S. Patent No. 5,069,960 discloses a thermally insulating foam glass tile that is coated with an outside surface to make a hard skin

to protect the outside of a building. The tiles disclosed are fabricated in extremely

small sizes, i.e., 18 cm x 18 cm x 6 cm, and the interior foam material which makes

up the bulk of the material is generally of a low density. Significantly, there is no

indication that the strength of the material disclosed is capable of absorbing

sufficient energy from an explosion, and indeed the size of the disclosed tiles would

not be ideally suitable for absorbing such energy.

[ 0007] Prior work by the inventors and others have developed methods for making foam glass tiles of a wide a variety of densities as described in U.S. Patent

No. 4,430,108 that can be used for building materials. While the techniques and

methods disclosed were useful to manufacture then-standard size tiles of 4.25 in. x 4.25 in. x .25 in., this disclosure does not teach how to manufacture tiles of a

larger size, for example 2 ft. x 2 ft. x 3 in. Likewise the tiles manufactured under

these methods were relatively light, e.g., less than 10 lbs., and were not

manufactured to withstand the effects of an explosion. To the contrary, these

methods sought to optimize the thermal insulation properties of the material, and

thus made smaller, lighter and weaker tiles.

[ 0008] While still others have worked on trying to make some large-size

porous shaped bodies, these have been smaller in critical dimensions and of lower

density than the present invention and not suitable to absorb a substantial amount of a shock wave which impacts the bodies associated with an explosion or

earthquake. For example, U.S. Patent No. 5,151,228 describes a process for

manufacturing large-size porous shaped bodies of low density by swelling, in order

to manufacture large-size cellular ceramic structural elements, e.g. , multi- story high

wall elements having a low weight. In the example, it discloses a tile 8.2 ft. x 1.64

ft. x 2 in., with a density of 26 lb./cu. ft. and a mass of 60 lbs. It also teaches to

obtain a low density in order to optimize thermal insulation. Thus, this foam when

exposed to a Shockwave from an explosion or earthquake will absorb very little of

the shock waves energy when it implodes.

[ 0009] Unlike the prior art discussed above, the tiles of the present invention

are designed and constructed of various materials so that such tiles have properties which are ideal for withstanding the shock wave associated with large explosions

or make a building or other structure resistant to earthquakes.

[ 0010] Thus, while the prior art is of interest, the known methods and

apparatus of the prior art present several limitations which the present invention

seeks to overcome.

In particular, it is an object of the present invention to provide a large, high density

foam glass tile which can be used as a facade on both exterior and interior building

walls.

[ 0011] It is another object of the present invention to increase from the

commercially recommended density of 9.5 lb./cu. ft. to have a higher density of between 30-100 lb./ cu. ft., and more particularly 40-60 lb./cu. ft.

[ 0012] It is a further object of the present invention to increase the weight

of the foam glass tile to be greater than 30 lbs., and more particularly over 65 lbs.

and even more particularly over 100 lbs.

[ 0013] It is a further object of the present invention to provide a large, high

density foam glass tile which can be used on the critical surfaces of buildings at

high risk for terrorist attacks, in combination with cement, steel or other high strength building materials. [ 0014] It is also an object of the present invention to provide a glass foam

tile that can be used in surfaces of typical buildings and has the advantage of

having a rigid structure that when exposed to shock waves having blast energy, the

tile can absorb a substantial portion of that blast energy. It also has the advantage

of being more resistant to earthquakes.

[ 0015] These and other objects will become apparent from the foregoing

description.

SUMMARY OF THE INVENTION

[ 0016] It has now been found that the above and related objects of the

present invention are obtained in the form of a large, high density foam glass tile

which can be used as a facade on both exterior and interior building walls. The

foam glass tile can also be used with other material to form a panel or a composite.

The present invention may be used on the critical surfaces of buildings at high risk

for terrorist attacks, in combination with cement, steel or other high strength building materials. The present invention may also be used in surfaces of typical

buildings. The present invention has the advantage of absorbing a substantial

portion of a shock wave caused by an explosion. The present invention also has the advantage of being more resistant to earthquakes. It must be noted that the

terms glass foam, foam glass, ceramic foam and foam ceramic are interchangable in the present invention. [ 0017] One embodiment of the present invention is a larger, higher density

foam glass tile with a closed pore outer skin that has an increased strength. These

heavy foam glass tiles will absorb more energy from an explosion, withstand higher

wind loading and other mechanical forces. The closed pore outer skin may either

be formed naturally or mechanically by bonding a secondary glass surface. The closed pore outer skin may have various color and texture variations which will

make the tile suitable for use as an exterior or interior facade of a building or other

structure. The density of the foam glass tile of the present invention is increased

from the commercially recommended density of 9.5 lb./cu. ft. to have a higher

density of between 30-100 lb./cu. ft., and more particularly 40-60 lb./ cu. ft. The weight of the foam glass tile of the present invention is greater than 30 lbs., and

more particularly over 65 lbs. and even more particularly over 100 lbs. And more

particularly, the tile will have a closed pore structure.

[ 0018] The large foam glass tile of the present invention which is capable of

being used as a building material for interior and exterior building surfaces and

having less seams than smaller tiles and which has a surface area of 2 ft. x 2 ft. or

greater, and more particularly has a surface area of 4 ft. x 4 ft. or greater. More

particularly, such tile may have a thickness of at least 2 in. and, more particularly, at least 3 in., and even more particularly at least 4 in.

[ 0019] Another embodiment of the high density foam glass tile of the pres ent

invention is capable of absorbing a substantial portion of a blast shock wave when subjected thereto. More particularly, such high density foam glass tile has a

density between 30-100 lbs./cu. ft. These high density foam glass tiles may be

backed to form a composite building material by a rigid structure, such as an

exterior concrete wall, building columns, structures located in or adjacent to

garages or other building structures located in the interior or exterior of a building

which are at risk of being exposed to potential blast shock waves. Even more

particularly, such tile may be backed by cementaceous materials having a

pozzolanic bond with the foam glass tile, or polymeric materials. Such tile may be

part of a larger panel and such panel may also have hanging hardware provided

therein, and may be mounted in a load bearing frame.

[ 0020] A further embodiment of the present invention is a ceramic-glass

foam composite made from a surface layer, at least one layer of rigid foam glass

and at least one backing layer. The surface layer may be made from materials

suitable for absorbing blast energy, and more particularly suitable for protecting

the composite from fragmentation, such as fibrous materials like graphite or Kevlar,

or polymeric materials. The surface layer may also be a foam glass glazed outer

surface of the rigid foam glass. More particularly, such tile has a density between

20-100 lb./cu. ft., and even more particularly between 30-80 lb./cu. ft. Such tile

has a closed pore structure. The surface finish layer may either be formed

naturally on the tile during the heating process or mechanically by bonding a

secondary surface. The closed pore outer skin may have various color and texture variations which will make the tile suitable for use as an exterior or interior facade of a building or other structure. More particularly, the surface finish layer may be

a non-foam layer, thus expanding upon the available color and texture variations

available for architectural appeal. The backing protective layer may be comprised

of one or more materials including, but not limited to, a fibrous composite, where

such fibers are made of high tensile strength materials, such as graphite, Kelvar

and/or fibreglass, or cementaceous materials, which may contain portland cement,

reinforced portland cement, lime, aluminous cement, plaster, polymeric material,

such as commercial thermosets and thermoplastics, concrete or reinforced

concrete. Such backing layer may also be reinforced by metal, Kevlar or other

supporting materials. A bonding promoter or adhesive may be applied between at

least one foam glass layer and the backing layer. The composite may also have

hanging hardware provided therein, and may be mounted in a load-bearing frame, and thus be capable of absorbing a substantial amount of shock waves and

vibration energy.

[ 0021] Another embodiment ofthe present invention is a ceramic-glass foam

composite comprising a foam glass tile and an inorganic cementaceous backing on

the foam glass tile, whereby the composite is capable of absorbing a substantial

portion of blast energy which it may be exposed to from a potential explosion.

Such foam glass tile may have a closed pore outer skin, which may either be

formed naturally or mechanically by bonding a secondary glass surface. The closed pore outer skin may have various colors and textures which will make the

tile suitable for use as an exterior or interior facade of a building or other structure. More particularly, such tile has a density between 20-100 lb./cu. ft., and more

preferably between 30-80 lb./cu. ft. Such tile may have a closed pore structure

which may either be formed naturally or mechanically by bonding a secondary

glass surface. Such inorganic cementaceous materials may contain portland

cement, reinforced portland cement, lime, aluminous cement, plaster, polymeric

material, concrete or reinforced concrete. The cementaceous backing may form a

pozzolanic bond with the foam glass tile. Alternatively, the cementaceous material

may bonded to the foam glass either by directly applying the cementaceous

material or by applying a layer of bonding promoter, such as Elmer's pro bond

concrete bonder adhesive-promoter. Even more particularly, hanging hardware may be installed in the cementaceous material either before the cementaceous

material is fully cured or after the cementaceous material is cured. The present

invention has the advantage of absorbing a substantial portion of a shock wave

caused by an explosion, in particular, when the tile is exposed in the direction of

the potential explosion.

[ 0022] An even further embodiment of the present invention is a foam glass

panel comprised of one or more large, high density foam glass tiles which can be

assembled into a lightweight building facade. Particularly, the closed pore structure is textured for architectural appeal, the tile has an interior portion and

the tile outer skin includes an additive to make its surface appear a different color

than the interior portion of the tile. More particularly, such panels can be used to make a building more resistant to earthquake damage than buildings made from

conventional concrete panels.

DETAILED DESCRIPTION OF THE INVENTION

[ 0023] The present invention relates to large, high density foam glass tiles

which can be used as a facade on both exterior and interior building walls. The

foam glass tile of the present invention can also be used with other materials to

form a panel or a composite. The present invention may be used on the critical

surfaces of buildings at high risk for terrorist attacks, in combination with cement, steel or other high strength building materials. The present invention may also be

used in surfaces of typical buildings. The present invention has the advantages of

being more resistant to earthquakes and/or wind loading.

[ 0024] Under one preferred embodiment of the present invention, the large,

high density foam glass tiles are capable of absorbing more energy from an

explosion than contemporary cement building materials, as well as withstand

higher wind loads and other mechanical abuse. Such large, high density foam glass

tiles may be fabricated in a variety of shapes, including but not limited to flat and/ or curved shapes. Further, the large, high density foam glass tiles of the

present invention are made from siliceous materials and gas forming foaming

agents, including but not limited to carbonaceous organics e.g., sugar and starch),

carbon black, silicon carbide, carbonates and sulfates. There are many possible methods to fabricate ceramic foam panels with various densities, sizes, and surface finishes. U.S. Pat. No. 4,430,108 describes various foam glass products fabricated

from fly ash and other additives with various densities, and surface finishes, the

disclosure of which is incorporated by reference herein. Foam glass with various

densities can be fabricated by varying the composition and type and concentration

of cellulating agents. Viscosity of glass is the dominating parameter during the

foaming process. In addition the pore structure, uniformity is dependent on the

distribution and particle size of the cellulating agent.

[ 0025] In the preferred embodiment for use in resisting explosions, the foam

glass tile of the present invention is larger and of a higher density than the

traditional foam glass tiles discussed herein. In particular, the preferred foam glass

tiles have a surface area of at least 2 ft. x 2 ft. and more particularly at least 4 ft. x 4 ft. in dimensions, and a depth of at least 2 in., and more preferably at least 3

in. and even more preferably at least 4 in.

[ 0026] Such large tiles are advantageous over conventional smaller tiles

because the larger size allows the composite of tiles to have less seams than

composites of smaller tiles conventionally used. Such seams can be detrimental to

the structural integrity since seams in a tile surface weaken due to thermal

expansion and contraction, and thus tend to crack. These seams are also a means

by which water can penetrate behind the tiles, resulting in damage from a variety of processes, such as molds, insects, and the freeze-thaw cycle. In the freeze-thaw

cycle, when water seeps into a tile and freezes it expands. When the water thaws, it contracts thereby causing the material to crack. When subjected to a shock wave

caused by an explosion, an improperly sealed seam will allow the wave to

penetrate behind the tiles, causing them to explode outward rather than absorbing

the desired energy. Thus, by reducing the number of seams, the risk of having

improperly sealed seams will be reduced. The larger tile surface also has the

further advantage of reducing labor at the labor site, by requiring less pieces to be

assembled, which in turn reduces labor costs.

[ 0027] Further, these foam glass tiles of the present invention are also

denser and heavier than conventional foam glass materials used in construction. Preferably, the density of the foam glass tile of the present invention is increased

from the commercially recommended density of 9.5 lb./cu. ft. to have a higher

density of between 20-100 lb./cu. ft., and more particularly 30-80 lb./cu. ft. The

weight of the foam glass tile of the present invention is greater than 30 lbs., and

more particularly over 65 lbs. and even more particularly over 100 lbs-.. Although

these densities and weights are higher than conventional foam glass, they still provide the advantage of being relatively less dense, and thus lighter than

traditional cement products used in construction.

[ 0028] The foam glass tile of the present invention preferably has a closed

pore outer skin, which thus provides the tile with increased strength and protects

the tile against water, and the freeze, thaw cycle. The closed pore outer skin may

either be formed naturally as taught in U.S. Pat. No. 4,430, 108 or mechanically by bonding a secondary glass surface as taught in U.S. Pat. No. 5,069,960, the

contents of which are incorporated by reference herein. Natural formation is

advantageous because it does not require additional labor and quality control, and

thus is more cost effective and less burdensome. Using a secondary glass surface

may also be advantageous because such techniques allow the closed pore outer

skin to have various color and texture variations which will make the tile

architecturally attractive for use as an exterior or interior facade of a building or

other structure. One way of making different color surfaces is by the use of

different color additives, as is generally well known to those skilled in the art.

[ 0029] Another advantage of the high density foam glass tile of the present

invention is that when it is exposed to a blast shock wave it is capable of absorbing

a substantial portion of the shock wave. Because these tiles are capable of

absorbing a substantial portion of a blast shock wave, they are particularly advantageous as building construction materials for interior and exterior surfaces

of buildings which are at risk of exposure to explosions, such as government

buildings, embassies and high visibility/famous buildings.

[ 0030] These high density foam glass tiles may be backed by a rigid

structure, such as an exterior concrete wall, building columns, structures located

in or adjacent to garages or other building structures located in the interior or

exterior of a building which are at risk of being exposed to potential blast shock waves. To provide for additional reinforcement to exterior walls, such tiles may be backed by cementaceous or polymeric materials. Examples of cementaceous

materials include, but are not limited to, concrete, reinforced concrete, portland

cement, reinforced portland cement, lime, aluminous cement, plaster. Examples

of polymeric materials include, but are not limited to, commercial thermos ets such

as polyesters, epoxies, polyurethane and silicones and commercial thermoplastic

such as PVC, polyethylene, polystyrene, nylons and polyesters and fibers of various

types, such as ceramic, carbon, glass, cellulose, graphite, Kevlar and polymer. The

composition of the foregoing materials have properties which facilitate and

improve the absorption of large forces. Such tile may also be part of a larger panel

and such panel may also have hanging hardware provided therein, and may be

mounted in a load bearing frame.

[ 0031] The foam glass tiles of the present invention are also thicker than

conventional foam glass tiles. In particular, the foam glass tiles of the present

invention are at least 2 in. thick, and are preferably at least 3 in. thick, and even

more preferably at least 4 in. thick. The increased thickness of the tile adds to the volume and therefore, to the weight of the tile. The increased thickness gives the

tile an increased stiffness, which reduces inadvertent fractures during handling,

whether from manufacturing, transporting or building. The increased thickness

will also permit the tiles to absorb more energy from explosions, exposures to

earthquakes or other shock waves. [ 0032] The selection of the particular size, thickness and density depends

upon the use to which the tile is intended to be made. For example, if the tile is

intended to be used to resist earthquakes, then the tiles should be optimized to be

the lowest weight that can withstand the wind pressure. By contrast, if the tile is

intended to protect a building or structure from shock waves associated with an

explosion, then the tile should be optimized to increase its density to be strong

enough to absorb such a shock wave. The desired thickness will depend upon the

proximity of the exposed tile to the location of the potential explosion. For

example, on the outside of a building, the thickness would have to take into

account the distance of the tile to the nearest location where an automobile or

truck with explosives may be parked. On the other hand, in an interior of a building, such as a support column, the proximity anticipated could be immediately

next to such a column, although the likely anticipated explosive load would be

substantially less.

[ 0033] For the purposes of resisting shock waves associated with an explosion, the tile of the present invention can be combined with a rigid backing

to form a composite panel. When the composite panel is exposed to the shock

wave, the exposed foam glass tile of the present invention will collapse or implode

and thereby absorb a substantial amount of the shock wave energy to which it is exposed, thus protecting the rigid backing, which in turn protects the building or

other structure. The rigid backing may be comprised of any one of the materials

discussed above with respect to the rigid structure. [ 0034] In the case of a tile to be used to make a structure resistant to

earthquakes, a slighter lighter tile may be used with a rigid backing. The load caused by wind pressure which needs to be resisted by these tiles is related to the

area between support columns. Thus, the greater the area between support

columns, the more resistance and greater strength will be required from the

composite tile with rigid backing. The thickness/density of the tiles to be used are

accordingly defined by these parameters . Thus, selection of these properties should

be optimized to provide the lightest system that can withstand the largest

anticipated wind pressure sought to be resisted with an appropriate safety factor

built in as is typically done in the construction industry. The tiles should be

supported by a metal frame, which in turn is supported by structural metal supports of the building or other structure.

[ 0035] For aesthetic purposes, the tiles with a finished layer can be used on

any surface subject to public view. Thus, if only one surface will be exposed to

public view, than only that surface needs to have the tiles with a finished layer. On the other hand, if both sides of a wall sought to be protected by the present

invention are subject to a public view, than a second tile with an appropriate

finished layer can be used on the second exposed side, such as the interior of the

building. Alternatively, other interior surfaces can also be used.

[ 0036] Another advantage of the tiles of the present invention is that such

tiles are also heat insulating as well as fire proof. Thus, these tiles have an added advantage of being able to be used to protect a support column from a terrorist fire

attack such as aMoltov cocktail, or other sources of fire. The use of the tiles of the

present invention can thereby either prevent and/or delay the destruction of such

support columns, thereby increasing the likelihood that occupants of an attacked

building will have sufficient time to evacuate.

[ 0037] Another embodiment of the tiles ofthe present invention can be used

to retrofit existing buildings or other structures. In particular, the tiles can be

mounted on the potentially exposed walls. If such walls are already sufficiently

rigid, then the tiles can be mounted directly thereon. If not, then the tiles can be

mounted on an appropriate rigid structure or backing protective layer to form a

panel, which in turn can be mounted on the exposed wall. Appropriate backing

protective layer may be a fibrous composite, where such fibers are made of high

tensile strength materials, such as graphite, Kelvar and/or fibreglass, or

cementaceous materials, which may contain portland cement, reinforced portland

cement, lime, aluminous cement, plaster, polymeric material, reinforced concrete.

Such backing layer may be reinforced by metal, Kevlar or other supporting materials. A bonding promoter or adhesive, such as Elmer's pro bond concrete bonder adhesive-promoter, may be applied between the at least one foam glass

layer and the backing layer. The composite may also have hanging hardware

provided therein, and may be mounted in a load-bearing frame, and thus be capable of absorbing a substantial amount of shock waves and vibration energy. [ 0038] In the preferred embodiment, the tile of the present invention can be

manufactured using raw materials which include (but are not necessarily limited

to) silica, fly ash, volcanic ash, diatomaceous earth, siliceous minerals, alkali

carbonates, calcium and magnesium minerals such as dolomite, and gypsum,

sodium silicate, borax, glass powders (such as cullet) and foaming agents. The

foaming agent can be selected from carbonaceous organics such as sugar and

starch, carbon black, silicon carbide, carbonates, sulfates and other like materials.

[ 0039] To make the tile of the present invention, various methods can be used. In one embodiment, the starting raw materials to make the tile are blended

together with water to form a homogenous slurry. It must be noted that even

though the preferred method of mixing is wet, nonetheless, dry blending may be

selected depending on type of raw materials used in foam glass formulation. For

instance, when glass powders (soda-lime glass cullet) is used as major raw

material, the gasifier can be dry blended in a conventional mixer, such as a ball mill. When wet blending is used, the solid content of the slurry is preferably

between 30-80 wt% , and more preferably between 50-70 wt%.

[ 0040] The slurry is then dried in a conventional dryer such as a spray dryer

to produce dry powders. If a static dryer is used, then the dried aggregates are ground to form dried powders. The resulting powdery product is then calcined to

a temperature at which the viscosity of the resulting foam glass is preferably

between 10⁷ to 10² poise, more preferably between 10⁵ to 10³ poise. Calcination may be carried out in a reducing environment to effectively pyrolize organic

gasifiers to microscopic carbon containing compounds. In the case of silicon

carbide as foaming agent, calcination may be carried out in a neutral air

atmosphere. When glass powders are used as major ingredients in the foam glass

formulations, calcination step is the same as the foaming step. Calcination can be

carried out in a rotary kiln, in stationary molds in a kiln, or in a fludizied bed

reactor heated primarily by a hot gas.

[ 0041] The calcined product may require pulverization if calcination for

instance is carried out in stationary molds. Calcination by fludization may not

require pulverization, if particles do not agglomerates in the fludized bed. The

calcined powders are screened preferably through 20 mesh screen, more preferably

through 40 mesh screen to remove the coarse particles. ,

[ 0042] The powders are then molded into desired shapes, in a metal mold. The preferred metals are stainless steel and chromium containing alloys such as

Inconel™ Inco Alloys. Inconel™ type alloys are preferred, since they can resist

thermal cycles, and oxidation better than stainless steels. Mold release agents are

preferably used to ease the de-molding process, and also minimize adhesion of the

foam glass to the metal which can cause unwanted cracking in the finished foam

glass product. The mold releasers should withstand the peak firing temperature, as a result inexpensive refractory oxides such as high silica minerals, high alumina

mineral powders such as diatomaceous earth, silica, and various clays can be used. Secondary oxide glazing or surface coating can be applied over the molded foam

glass powder precursor, to produce additional surface effect in the finish foam

product.

[ 0043] The molds are then transferred into either electric or gas fired kilns

that can accommodate the molds with a temperature uniformity better that 50 °C

across any dimension of the mold, more preferably better than 20 °C. The heating

rate is selected based on the foam glass thickness, and product loading inside the kiln. Normally the heating rate may fall between 2-10 °C/min., and preferredly

between 3-5 °C/min. At the peak foaming temperature the foam glass viscosity is

between 10⁵ to 10³ poise. The soak time at the peak firing temperature depends

on the foam glass dimensions. The soak time also effects the surface glazing

thickness. Longer soak time results in the formulation of thicker surface glaze or skin. The larger foams may require longer soak times to ensure temperature

equilibration throughout the foam body.

[ 0044] During cooling cycle to room temperature, thermal stresses across the

foam glass need to be minimized to ensure a strong product free of residual

thermal stresses. As a result the cooling rate around the annealing and strain

point temperatures which correspond to an approximate viscosity range of 10¹² to

10¹⁶ will be relatively slow, between 1-5 °C/min, preferably between 1-3 °C/min.

Above and below this temperature range, depending on the foam dimensions, the

average cooling rate is from 2-10 °C min., preferably 3-5 °C/min. [ 0045] The annealed foam glass will be de-molded, and trimmed on its sides

if needed. Trimming can be done by various means such as grinding and cutting.

Cutting with an abrasive resistant blade such as carbide blade is preferred, since

it produces less dust than grinding. It should be noted that the foam glass dust is

primarily composed of non- crystalline silica, which is much less harmful than crystalline silica dust, such as concrete dust.

[ 0046] The foam glass board produced can be used as a stand alone tile, or

be used in fabrication of foam glass composite panels. All the trimming and dust

collected during the final step will be ground and added to the starting raw materials. In addition, any product reject, such as broken tiles or panels will be

ground and recycled back into the starting raw materials.

[ 0047] It will be understood by those skilled in the art that the foregoing

method of making the tiles of the present invention could be modified or other

methods of fabrication can be used without departing from the spirit and scope of

the invention.

[ 0048] As discussed above, an aspect of the present invention is the inclusion of backing materials to the foam glass tile. Examples 1 and 2, below illustrate the

application of portland cement as backing material. These examples demonstrate

that pozzolanic bonding occur naturally at the interface of the foam glass tile and

the cement containing backing layer. [ 0049] Alternatively, other inorganic cementaceous backing materials can

be applied over the foam glass tile to a desired thickness, preferably initially as a

paste which will harden to a solid backing. The backing can be made into a

multilayer structure, where lime or portland cement will be the adjacent layer to

the foam to develop pozzolanic bond, followed by other cementaceous over layers .

The cement backing materials can be reinforced by addition of fibers of glass, graphite, ceramics, polymers such as cellulose, metals, Kevlar or alike.

[ 0050] It is also possible to join the foam glass tile with other solid layers via

a joining compound. For instance, appropriate contact adhesives can be applied between a sheet of metal and foam glass. One such adhesive that can be used with

aluminum sheets is a silicone based adhesive. Other examples are application of

a polymeric foam between the foam glass and another backing material to protect

the polymeric foam. Polyurethane foam and cement board are examples of this

type of multilayer backing. The advantage of polyurethane foam is that, it can be applied in place into a gap between a pre-positioned foam glass board and a

sheathing back layer. Polymeric backing are particularly useful to reduce

fragmentation of the brittle layers such as foam glass and more so of the

cementaceous layers. The backing layer may contain multiple layers of foam glass

bonded together with cement, polymeric foams or other contact adhesives.

[ 0051] The foam glass backing may be selected to have different density

than the main foam glass panel for maximum absorption of shock wave energy. The front face of the foam glass layer normally is glazed as discussed before.

However, a surface finish may be applied according to the present invention to

impart additional protection and aesthetic appearance to the composite foam glass

structure. The surface finish can be applied before or after the backing layers are

installed. The finish can be a textured cementaceous and/or polymeric overlayer

to display for instance a brick facing or marble type appearances. These finishes

can be molded in place over the foam layer or be adhered to the foam as a separate sheathing via a contact adhesive or a cement layer with pozzolanic activity. These

finishes would impart additional architectural appeal to the foam glass composite

structure. In addition, colorants can be used in surface finishes to impart desired

colors to the structure. Fibrous materials can be added to the surface finishes to

impart additional reinforcement and to reduce fragmentation upon shock wave reception. Various UV protecting compounds can be added to the surface finishes

if desired.

[ 0052] The thickness of both backing layers and the surface finishes can vary

upon design specifications, required energy absorption and strength. The application of a surface finish may be unnecessary since the natural glazing of the

foam glass panel as fired may be aesthetically sufficient. EXAMPLE 1

[ 0053] A foam glass tile was made by blending the raw materials set forth

in Table 1 below:

TABLE 1

[ 0054] The resulting slurry was dried, and the powder mixture was calcined

at 950 °C for about 45 minutes to react the raw materials, and decompose sugar

to finely, and evenly dispersed carbonaceous phase. The calcined product was ground to fine powders, placed in an Inconel™ mold, and was foamed by heating

to about 850 °C and soaked at that temperature for approximately 30 minutes. The

resulting foam glass was annealed to room temperature and de-molded. The

resulting foam glass had a density of about 25 lb./cu. ft., a dark greenish color, and a completely glazed surface. The pore structure was uniform with an average pore

size of about 2 mm. After trimming the edges the tile had a dimension of

approximately 16 in. x 12 in. x 3 in. [ 0055] The foam glass-concrete composite tile according to the present

invention was made by the following method. The foam was trimmed around its

sides and was framed with strips of plywood around its perimeter with the glazed

surface faced down, leaving a gap of about 1 in. above the tile to receive cement.

A portland cement sand mix (Quickrete sand mix) was prepared according to the

manufacturer instruction. The resulting paste placed over the exposed face of the foam which was in contact with the mold during firing, and was not trimmed to

expose the cell structure before making the composite tile. The concrete was

allowed to cure for about 28 hours, before being removed from the form. The

interface between the foam and concrete layers were completely sealed indicating

a strong cementaceous pozzolanic bond formation.

EXAMPLE 2

[ 0056] A foam glass tile was made by blending the raw materials set forth

in Table 2 below:

TABLE 2 [ 0057] The resulting slurry was dried, and the powder mixture was calcined

at 900 °C for about 30 minutes to react the raw materials, and decompose sugar

to finely, and evenly dispersed carbonaceous phase. The calcined product was

ground to fine form powders, was placed in an Inconel™ mold, and was foamed

by heating to about 860 °C with an average heating rate of about 3.5 °C/min. The

resulting foam was annealed to room temperature and de-molded. The foam glass

had a density of about 52 lb./cu. ft., a greenish color, and a completely glazed

surface. The pore structure was uniform with an average pore size of about 1-2 mm. After trimming the edges the tile had a dimension of approximately 17 in. x

12 in. x 1.4 in.

[ 0058] The foam glass-concrete composite tile according to the present

invention was made by the following method. The foam was trimmed around its

surface faced down, leaving a gap of about 1 inch above the tile to receive cement. A thin layer of Elmer's pro bond concrete bonder adhesive-promoter was applied

to the foam. A portland cement mortar mix (Sakrete mortar mix) was prepared

according to the manufacturer instruction. The resulting paste was placed over the

exposed face of the framed foam glass tile and leveled. This was the face in contact

with the firing mold, and was not trimmed to expose the cell structure before

making the composite tile. The concrete was allowed to cure for about 28 hours, before being removed from the form. The interface between the foam and concrete layers were completely sealed indicating a strong cementaceous pozzolanic bond

formation.

[ 0059] Now that the preferred embodiments of the present invention have

been shown and described in detail, various modifications and improvements

thereon will become readily apparent to those skilled in the art. Accordingly, the

spirit and scope of the present invention is to be construed broadly and limited

only by the appended claims and not by the foregoing specification.

Claims

What is claimed is:

1. A foam glass tile comprising a closed pore outer skin on at least one

side, having a density between 30 lb./cu. ft. and 100 lb./cu. ft., and having a

weight greater than 30 lb.

2. The foam glass tile according to claim 1, wherein the tile surface area

is at least 2 feet by 2 feet.

3. The foam glass tile according to claim 1, wherein the tile surface area

at least 4 feet by 4 feet.

4. The foam glass tile according to claim 1, wherein the tile has a

density greater than 40 lb./cu. ft.

5. The foam glass tile according to claim 1, wherein the tile has a

density greater than 50 lb./cu. ft.

6. The foam glass tile according to claim 1, wherein the tile has a

thickness of at least 3 inches.

7. The foam glass tile according to claim 1, wherein the tile has a

thickness of at least 4 inches.

8. The foam glass tile according to claim 1, wherein the tile has a weight of at least 65 lbs.

9. The foam glass tile according to claim 1, wherein the tile has a

weight of at least than 100 lbs.

10. The foam glass tile according to claim 1, wherein the tile is assembled

with at least one other tile of like construction to form a panel, said panel is used

as a lightweight building facade.

11. The foam glass tile according to claim 10, wherein said building

facade is assembled into at least a portion of a building so that said portion of said

building will be substantially resistant to earthquake damage.

12. The foam glass tile according to claim 1, wherein said tile has a

closed pore structure.

13. The foam glass tile according to claim 12, wherein said outer skin is

a glazed outer surface of said foam glass tile.

14. The foam glass tile according to claim 12, wherein said closed pore structure is textured for architectural appeal.

15. The foam glass tile according to claim 12, wherein the tile further

comprises an interior portion and said tile outer skin comprises an additive to make its surface appear a different color than said interior portion of said tile.

16. A composite building material comprising:

(a) a foam glass tile having a density between 20 lb./cu. ft. and 100

lb./cu. ft.; and

(b) a rigid structure, whereby said tile is backed by said rigid structure so that if subjected to

blast shock waves having blast energy, said tile can absorb a substantial

portion of said blast energy to which said tile is exposed.

17. The composite building material according to claim 16, wherein said

rigid structure is a building column.

18. The composite building material according to claim 16, wherein said

rigid structure is located in or adjacent to a garage.

19. The composite building material according to claim 16, wherein said rigid structure comprised of one or more cementaceous materials.

20. The composite building material according to claim 19, wherein said

cementaceous materials comprise portland cement.

21. The composite building material according to claim 19, wherein said cementaceous materials comprise lime.

22. The composite building material according to claim 19, wherein said

cementaceous materials comprise an aluminous cement.

23. The composite building material according to claim 19, wherein said

cementaceous materials comprise plaster.

24. The composite building material according to claim 16, wherein said

rigid structure comprises polymeric materials.

25. The composite building material according to claim 24, wherein said

polymeric material is comprised of fibrous materials and/or Kevlar.

26. A ceramic-glass foam composite comprising:

(a) a foam glass tile; and

(b) an inorganic cementaceous backing on said foam glass tile,

whereby said composite is capable of absorbing a substantial portion of

blast energy which it may be exposed to from a potential explosion.

27. The ceramic-glass foam composite according to claim 26, wherein

said foam glass tile is exposed in the direction of said potential explosion.

28. The ceramic-glass foam composite according to claim 26, wherein

said cementaceous backing forms a pozzolanic bond with said foam glass tile.

29. The ceramic-glass foam composite according to claim 26, wherein

said cementaceous backing is reinforced cement.

30. The ceramic-glass foam composite according to claim 26, wherein

said composite is mounted on a building column.

31. The ceramic-glass foam composite according to claim 26, wherein

said composite is mounted on a wall located in or adjacent to a garage.

32. A foam glass composite panel comprising:

(a) a surface finish layer;

(b) at least one layer of rigid foam glass; and

(c) at least one backing layer.

33. The foam glass composite panel according to claim 32, wherein said

rigid foam glass has closed pore structure.

34. The foam glass composite panel according to claim 32, wherein said

surface finish layer is a foam glass glazed outer surface of said at least one layer of

rigid foam glass.

35. The foam glass composite panel according to claim 32, wherein said

surface finish layer is textured for architectural appeal.

36. The foam glass composite panel according to claim 32, wherein said

surface finish layer includes an additive to make its surface appear a different color

than said at least one layer of rigid foam glass.

37. The foam glass composite panel according to claim 32, wherein said

surface finish layer contains fibrous materials.

38. The foam glass composite panel according to claim 37, wherein said

fibers are made from graphite and/or Kevlar.

39. The foam glass composite panel according to claim 32, wherein said

at least one backing layer contains fibrous materials.

40. The foam glass composite panel according to claim 39, wherein said

fibers are made from graphite and/or Kevlar.

41. The foam glass composite panel according to claim 32, wherein said surface finish layer comprises a polymeric material.

42. The foam glass composite panel according to claim 32, wherein said

at least one backing layer comprises a polymeric material.

43. The foam glass composite panel according to claim 32, wherein said

at least one backing layer comprises one or more cementaceous materials.

44. The foam glass composite panel according to claim 43, wherein said

cementaceous materials form a pozzolanic bond with a surface of said at least one

foam glass layer. ,

45. The foam glass composite panel according to claim 43, wherein said

cementaceous materials comprise portland cement.

46. The foam glass composite panel according to claim 43, wherein said

cementaceous materials comprise reinforced portland cement.

47. The foam glass composite panel according to claim 43, wherein said cementaceous materials comprise lime.

48. The foam glass composite panel according to claim 43, wherein said

cementaceous materials comprise an aluminous cement.

49. The foam glass composite panel according to claim 43, wherein said

cementaceous materials comprise plaster.

50. The foam glass composite panel according to claim 43, wherein a

layer of a bonding promoter or adhesive is applied between said at least one foam

glass layer and said backing layer.

51. The foam glass composite panel according to claim 32, wherein said

at least one backing layer comprises metal.

52. The foam glass composite panel according to claim 32, wherein

hanging hardware is installed in the backing layer.

53. The foam glass composite panel according to claim 32, wherein said panel is mounted on a load-bearing frame.

54. The foam glass composite panel according to claim 53, wherein said

panel is capable of absorbing a substantial amount of shock waves and vibration

energy.

55. The foam glass composite panel according to claim 32, wherein said surface finish layer is capable of containing fragments of said one or more glass

foam layers in the case of a shock wave.

56. The foam glass composite panel according to claim 32, wherein said one or more backing layer is capable of containing fragments of said one or more

foam layers in the case of a shock wave.

57. The foam glass composite panel according to claim 32, wherein said

panel is assembled into at least a portion of a building so that said portion of said

building will be substantially resistant to earthquake damage.