The Coal Ash scientist and Coal Ash marketing company we cite initially herein have appeared previously in our reports, as in:
West Virginia Coal Association | Texas Converts Coal Ash to Cash | Research & Development;
which concerned "Boral Material Technologies Incorporated", of Texas, themselves a subsidiary of a larger Australian construction materials company, and several of their Coal Ash utilization technologies:
"United States Patent: 6916863 - Filler Comprising Fly Ash for Use in Polymer Composites; 2005; Assignee: Boral Material Technologies; Abstract: The present invention is a fly ash filler or filler blend ... that can be combined with a polymer at higher filler loadings to produce a filled polymer for polymer composites that, in many cases, can produce improved mechanical properties for the polymer composites over polymer composites using conventional fillers"; and:
"United States Patent: 7241818 - Filler Comprising Fly Ash for Use in Composites; 2007; Assignee: Boral Material Technologies; Abstract: The present invention is a fly ash filler or filler blend having a particle size distribution with at least three modes that can be combined with a polymer or bitumen at higher filler loadings to produce a filled polymer or bitumen for composites that, in many cases, can produce improved mechanical properties for the composites over composites using conventional fillers"; and:
"United States Patent: 7879144 - Filler Comprising Fly Ash for Use in Polymer Composites; 2011; Assignee: Boral Material Technologies; Abstract: The present invention is a fly ash filler or filler blend ... that, in many cases, can produce improved mechanical properties for the polymer composites over polymer composites using conventional fillers. As a result, superior polymer composites (e.g. those used in carpet backing) can be produced at a lower cost than conventional polymer composites".
Those several technologies were developed by a team of collaborating scientists working in a number of different places under the supervision, or at least the coordination, apparently, of their team leader, one Raymond Hemmings, of Kennesaw, Georgia.
And, herein we learn that those Coal Ash utilization technologies and processes evolved from earlier work by Hemmings and friends, wherein they had developed a productive use for Coal Ash that, like mixing Coal Ash into concrete, perhaps should have been obvious, but might just be over most of our heads.
Any old semi-country boy who worked every summer between school terms might well have found himself, as did one among our number here, employed in the somewhat seasonal trade of roofing: installing roof coverings of one sort or another on newly-constructed houses and buildings, or replacing roofs on older homes.
There are, in fact, a number of different types of roof coverings, i.e., the final finish intended to, basically, waterproof the structure; but, the one most people are aware of and familiar with is shingles.
And, although shingles started out in the olden times being made from thin slats of wood or slate, almost all of them nowadays, as they have been for quite a while, are what as known as "asphalt" shingles, and are all manufactured pretty much as described in:
Asphalt shingle - Wikipedia, the free encyclopedia; "Two types of asphalt shingles are used: 'organic', and 'fiberglass' or 'glass fiber'. Organic shingles are generally paper (waste paper) saturated with asphalt to make it waterproof, then a top coating of adhesive asphalt is applied and ceramic granules are then embedded. Fiberglass shingles have a base layer of glass fiber reinforcing mat. The mat is made from wet, random-laid fiberglass bonded with urea-formaldehyde resin. The mat is then coated with asphalt which contains mineral fillers and makes the fiberglass shingle waterproof".
And, it's that "mineral fillers" part that is of interest to us herein.
The better part of a decade ago, the crew from Boral Material Technologies figured out that Coal Ash would serve in that function just fine, as seen in excerpts from the initial link in this dispatch to:
"United States Patent 6,695,902 - Asphalt Composites Including Fly Ash Fillers or Filler Blends
Date: February, 2004
Inventors: Raymond Hemmings, GA, et. al.
Assignee: Boral Material Technologies, TX
Abstract: The present invention is a fly ash filler or filler blend having a particle size distribution with at least three modes that when combined with asphalt produces asphalt composites such as roofing shingles with improved mechanical properties at a lower cost than asphalt shingles produced using conventional calcium carbonate fillers. The present invention also includes a method for producing an asphalt composite, comprising the steps of combining asphalt with a fly ash filler or a filler blend ... and producing an asphalt composite with the resulting filled asphalt. The present invention further includes a method of determining what fly ashes can be used as fillers for asphalt composites such as roofing shingles. The fly ash filler or filler blend can be used in amounts of greater than 45% by volume or greater than 70% by weight to increase the mechanical properties of the asphalt composites such as the pliability, tensile strength and tear strength while decreasing the cost to produce the asphalt composites.
(Note that the Ash is replacing "calcium carbonate fillers", that is, basically, ground up limestone, with all of the quarrying and processing costs, and environmental disruption, that entails.)
Claims: An asphalt composite comprising asphalt and a filler, said filler comprising a blend of a fly ash and at least one other filler wherein the filler blend has a particle size distribution having at least three modes.
The asphalt composite ... wherein the particle size distribution includes a first mode having a median particle diameter (as specified, and) wherein the at least one additional filler in the filler blend is a second fly ash.
The asphalt composite ... wherein the filler blend comprises a high fine particle content fly ash filler and a low fine particle content fly ash filler.
An asphalt composite comprising asphalt and a subbituminous coal fly ash filler (and) wherein the subbituminous fly ash is a Class C fly ash.
An asphalt composite comprising asphalt and a filler having a particle size distribution with at least three modes, the filler comprising fly ash and having a loading of greater than 70% by weight."
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We close our excerpts from "United States Patent 6,695,902" there, so that we can emphasize a few things, the main thing being that we can make roofing shingles that consist, by weight, mostly of Coal Ash.
But, if you read the full Disclosure carefully, you'll see that it specifies only "subbituminous fly ash ... a Class C fly ash", which is pretty much what they get by burning the Coal they mine down in Texas, where Boral Mineral Technologies is headquartered.
However, also note that the "filler blend" can also contain "one additional filler" which can be "a second fly ash", although the traditional ground up limestone, as Hemmings, et. al., stipulate, can also be used.
The reason, it seems apparent to us, that it was written that way is so that they could lock up some rights to using Coal Ash in roofing shingles, without infringing on the rights to another, closely-similar patented technology, wherein Class F Fly Ash, as we get by burning our eastern bituminous Coal, is specified as the material of choice to "fill" asphalt-based roofing compositions, as seen in:
"United States Patent: 5565239 - Asphaltic Roofing Material Containing Class F Fly Ash Filler
Date: October, 1996
Inventor: Clinton Pike, GA
Assignee: JTM Industries, GA
Abstract: Asphaltic roofing material, such as roll or shingle roofing, employs Class F fly ash as the filler to the asphaltic base material. The fly ash is readily heated and promotes a more rapid cooling of the composite asphaltic web prior to rolling or cutting into shingles. The Class F fly ash comprises between 40% and 70% of the hot asphaltic mixture, by weight. It may be delivered to the roofing plant in a state of elevated temperature from the fly ash source to reduce the requirement for preheating the fly ash or eliminating the preheating step altogether. The slightly acidic content of fly ash discourages the growth of fungus and mold on the roofing material in hot and humid climates, and the resulting shingle has enhanced overall flexibility and resistance to cracking at low temperatures.
(There are, it seems, a lot of benefits to using our Class F Coal Ash in asphaltic roofing products.)
Claims: The method of making an asphaltic roofing material in the form of a shingle or a roll in which a heated asphaltic mix is applied to a substrate web, and in which the heated asphaltic mix includes an asphaltic base and a filler, comprising the steps of: heating said asphaltic base to permit application to the substrate web, blending with said heated asphaltic base a heated filler consisting essentially of Class F fly ash and forming a heated mixture of asphaltic base and Class F fly ash, applying said heated mixture to said substrate web to form a coated composite, applying roofing granules to said coated composite, and cooling said coated composite with said applied granules to form said roofing material.
The method ... in which said Class F fly ash comprises about 40% to 75% of weight of said heated mixture.
The method ... comprising the further steps of collecting said Class F fly ash in a heated condition from a fly ash storage facility of a pulverized coal burning power plant and delivering said fly ash while still heated for blending with said heated asphaltic base to form said heated mixture.
(The point of the above being, that, since the asphalt and fly ash blend has to be heated to a certain temperature, in any case, for the shingle manufacturing process, if we get the Fly Ash while it's still hot, fresh out of the boiler furnaces, and use it straightaway, then we could conserve energy in the overall shingle making process.)
Background: This invention relates to asphaltic or bituminous roofing materials and methods, and more particularly to the manufacture of such roofing materials in which fly ash comprises the major part of the inert filler in the asphalt mix.
In the manufacture of roofing shingles or rolls, a heated asphaltic/filler blend is applied to a substrate web, such as a glass fiber mat or a felt. After the mat or web is impregnated with the asphaltic mix, a granular surface treatment may be applied to the hot asphaltic surface and rolled or pressed into place. The coated web composite is then cooled so that it may be cut and bundled as shingles, or formed into rolls.
Prior to application to the substrate or base web, the asphalt is heated in an asphalt heater to a temperature of around 500F. The heated asphalt is then blended with an inert filler which has also been preheated to a temperature necessary so as not to chill the mix and to facilitate blending of the filler with the asphalt.
The choice of filler has traditionally been based on considerations of availability, compatibility, and cost. An inert filler material which has been preferred and used by many roofing plants is that of powdered limestone (calcium carbonate), usually at a rate of about 40% to 70% by weight of the mix.
The rate at which an asphaltic roofing material plant can effectively operate is limited by a number of factors. One such factor is that the rate of production must allow for sufficient cool-down time to permit correct cutting and bundling of the shingles. At some production facilities, high ambient temperatures impede satisfactory chilling of the asphaltic composite felt or web. In spite of the use of water cooled chill rolls, high temperatures require a slowing down of production during periods of high ambient temperature. Little attention seems to have been paid to the use of materials, such as the selection of a filler, which would enhance, rather than impede, the cooling of the hot composite.
Powdered limestone often has been a filler of choice as it is widely available at a relatively low cost, and is compatible with the asphalt mix. However, it is a poor conductor of heat when compared to fly ash. It is relatively slow to heat, and thereafter, in the mix, tends to insulate the asphalt and retard the cooling of the composite web.
Calcium carbonate (limestone) is an active base material, and it therefore tends to be acted upon by the weak acid in the precipitation (acid rain) and is believed to contribute to a shortened life of the roofing material. More importantly, the limestone filler has been documented as the cause of algae growth and discoloration in asphaltic shingled roofs. The principle, if not the only alga which attacks roofs is of the genus gloeacapsa, an organism which grows naturally in harsh environments on limestone cliffs, cement or limestone walls, and roofs formed with a limestone filler. The limestone filler material is thought to give the alga a competitive advantage over other microorganisms, since limestone is a sedimentary rock derived from marine organisms and is rich in nutrients. The carbonate released from the limestone is believed to provide a moderately alkaline environment that favors algal growth. Besides nourishment, the porosity of the limestone filler retains moisture and provides a growth surface for the alga.
Summary: This invention relates to the manufacture of asphaltic roofing material in which the asphaltic filler is substantially or exclusively fly ash.
While (others have noted) fly ash as one of a large number of possible inert fillers for asphaltic mixes, its particular properties and advantages are not believed to have been recognized as a substitute for calcium carbonate in the manufacture of roofing rolls and shingles. Also, the references in which fly ash has been mentioned have not identified fly ash by its particular type or by its characteristics which enhance the manufacture and improve the quality of the final product. In particular, the art has failed to recognize the role played by the filler in the cooling of the hot laminate during manufacture, or its role in the resistance to weathering caused by the weakly acidic content of certain precipitation or the resistance which it imparts to the growth of mold.
It has been discovered that asphaltic roofing materials, such as "felted" roll and shingle materials, can be manufactured with less heat energy expended and with a shortened cooling time, by the use of a filler comprising Class F type fly ash ... . Generally, this fly ash is a waste byproduct of burning pulverized bituminous (eastern) coal which is collected by electrostatic precipitators at coal burning power plants."
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The full Disclosure goes on to describe some other benefits of using bituminous Coal Ash as a filler in asphalt roofing material, such as an improved resistance to cracking during processing and handling; but, the advantages should be apparent:
Asphalt roofing products containing Coal Ash filler are more economical to make, and, they're more resistant to temperature fluctuations and to chemical and microbial deterioration.
They are, simply, better and cheaper.