United States Patent Application: 0120024196
We've documented for you a number of times, most recently in our report of:
West Virginia Coal Association | Drexel University Formulates Coal Ash "Geopolymer" | Research & Development; concerning: "United States Patent 5,601,643 - Fly Ash Cementitious Material and Method of Making a Product; 1997; Assignees: Drexel University, Philadelphia, and By-Products Development Company, PA; Abstract: Rapid curing, high strength cementitious binder mixtures are provided containing fly ash and an alkali metal or alkaline earth metal silicate binder ... . Any of the binder, mortar and concrete mixtures can be cured under elevated temperatures to yield high strength products";
that, Coal Ash can be very productively utilized and consumed in the manufacture of what are becoming known as "Geopolymers", that is, a special type of cement and/or concrete wherein the element silicon participates in the formation of what can be considered as inorganic polymers; materials that are considerably stronger, and much more resistant to chemical attack and corrosion, than conventional Portland-type cement and concrete.
So much stronger and durable are such Coal Ash based cements and concretes, in fact, that, as seen in our report of:
West Virginia Coal Association | Coal Ash in Concrete Saves $100 Billion | Research & Development; concerning, in part, the report: "The Economic Impacts of Prohibiting Coal Fly Ash Use in Transportation Infrastructure Construction; 2011; American Road & Transportation Builders Association; Coal fly ash ... is a naturally-occurring product of the coal combustion process. It is nearly identical in composition to volcanic ash. When mixed with calcium hydroxide, it has many of the same properties as cement. Replacing a portion of the cement with fly ash creates a cementitious material that, when used as an input with aggregates, water and other compounds, produces a concrete mix that is well-suited to road, airport runway and bridge construction. Fly ash concrete has a number of very significant, well-documented benefits ... . It is more durable, yet less expensive than other traditional portland cement blends. Our analysis has found that such an action would increase the average annual cost of building roads, runways and bridges in the United States by nearly $5.23 billion. This includes a $2.5 billion increase in the annual price of materials and an additional $930 million each year in pavement repair work and $1.8 billion in bridge work due to the shorter pavement life of portland cement concrete without fly ash.Over 20 years, the additional cost would be $104.6 billion. Fly ash is a key component of high performance concrete pavement designed for a lifespan of 30 to 60 years for concrete roads, compared to the current average of 20 to 25 years";
using them to replace conventional cement and concrete in the building of our transportation infrastructure could, due to the longer service life of such Coal Ash cements and concretes, save us a ton of money.
More about Coal Ash geopolymers, and why and how they work so well as replacements for Portland-type cement and concrete, can be learned via secondary reference links included in our report of:
West Virginia Coal Association | Coal Ash Polymer Reduces CO2, Gives Concrete Longer Life | Research & Development; which centered on: "United States Patent 8,512,468 - Geopolymer Mortar and Method; 2013; Assignee: Louisiana Tech University Research Foundation; Abstract: A geopolymer mortar formed by mixing about 35% to about 45% by weight pozzolanic material, about 35% to about 45% by weight silicon oxide source, about 15% to about 20% by weight alkaline activator solution, and about 0.3% to about 2.5% by weight copper ion source. The pozzolanic material may be fly ash ... . The geopolymer mortar may be applied as a protective coating on a surface of a structure".
And, herein we learn that yet another United States institution of higher learning has established technology for so utilizing Coal Ash in the formulation of such valuable, high-performance Geopolymers. As disclosed in excerpts from the initial, and one following, link in this dispatch to:
"United States Patent Application 20120024196 - Tailored Geopolymer Composite Binders for Cement and Concrete Applications
Date: February 2, 2012
Inventors: Weilang Gong, et. al., MD and VA
Assignee: The Catholic University of America
(The Catholic University of America - Homepage - News, Events, Experts
The Catholic University of America - Wikipedia, the free encyclopedia; "The Catholic University of America (CUA) is a private university located in Washington, DC in the United States. It is a pontifical university of the Catholic Church in the United States and the only institution of higher education founded by the U.S. Catholic bishops. Established in 1887 as a graduate and research center following approval by Pope Leo XIII on Easter Sunday, the university began offering undergraduate education in 1904. It has been called one of the 25 most underrated colleges in America, one of the nation's best colleges by the Princeton Review (and) "one of the most eco-friendly universities in the country".)
Abstract: A geopolymer composite binder is provided herein, the composite binder including (i) at least one fly ash material having less than or equal to 15 wt % of calcium oxide; (ii) at least one gelation enhancer; and (iii) at least one hardening enhancer having a different composition from a composition of the at least one fly ash material.
Claims: A dry mixture for a geopolymer binder, comprising: (i) at least one fly ash material comprising less than or equal to 15 wt % of calcium oxide; (ii) at least one gelation enhancer; and (iii) at least one hardening enhancer having a different composition from a composition of the at least one fly ash material (and) wherein the at least one fly ash material is a Class F fly ash material (and)wherein the at least one hardening enhancer comprises blast furnace slag, Class F fly ash having more than 8 wt % calcium oxide, Class C fly ash, gypsum, an alkali-earth compound, a calcium rich pozzolanic material, a calcium rich zeolite, calcium hydroxide, aluminum hydroxide or combinations thereof.
(There are a number of different ways and amounts, as per the above excerpt, in which Coal Fly Ash, both Class F and Class C, can be used in the composition. Our excerpts are perhaps a little too-abbreviated, and, much more can be learned via the full Disclosure.).
The dry mixture ... wherein ... the at least one fly ash material comprises at least about 60 wt % of the dry mixture.
(A range of blending proportions is defined; but, the above "60 wt %" appears to be the average, or mean, amount of Coal Ash in the "dry mixture".)
A geopolymer composite binder, made by combining the dry mixture ... and an activator (and) wherein the activator comprises an activator alkaline solution comprising a metal hydroxide and a metal silicate (as specified).
A concrete or mortar geopolymer composition made by combining the binder ... with at least one aggregate (and) wherein the composition has a seven day compressive strength of at least about 10000 psi and a room temperature setting time of 30 minutes to 3 hours.
(The "seven day compressive strength of ... 10000 psi" is impressive. More clearly, it is 10,000 pounds per square inch, and, as can be learned via:
Concrete Properties; a compressive strength of between 3,000 to 6,000 pounds per square inch, psi, would be typical of "normal strength" Portland-type cement concrete. This is high-performance stuff.)
A concrete or mortar geopolymer composition which has a seven day compressive strength of ... 10000 psi to 12530 psi and a setting time of 1 to 3 hours at room temperature.
The method ... wherein the composition comprises a mortar composition (or) wherein the composition comprises a concrete composition (with) a Class F fly ash material comprising at least 60 wt % of the dry mixture ... .
(Various blends are specified and provided for illustration. "Class F fly ash" is what we get from burning our high-grade eastern bituminous Coal. Class C ash, as obtained from lignite Coal, can also be used, as per the more complete Disclosure.)
A method of making a concrete or mortar composition, comprising: forming a composition by mixing at least one activator and at least one aggregate with a dry mixture comprising: (i) a Class F fly ash material comprising at least 60 wt % of the dry mixture; (ii) a metakaolin gelation enhancer comprising greater than zero and less than 25 wt % of the dry mixture; and (iii) a blast furnace slag or Class C fly ash hardening enhancer comprising greater than zero and less than 25 wt % of the dry mixture; and setting the composition in 30 minutes to 3 hours at setting temperature between 20 and 75 C, and curing the composition for at least 24 hours at a curing temperature between 20 and 75 C to form the concrete or mortar composition having seven day compressive strength of at least about 10000 psi.
Background: The present invention relates to geopolymer composite binders for cement and concrete and methods of making and using thereof. Geopolymers comprise of silicon and aluminum atoms bonded via oxygen atoms into a polymer network. Geopolymers are prepared by dissolution and poly-condensation reactions between a reactive aluminosilicate material and an alkaline silicate solution, such as a mixture of an alkali metal silicate and metal hydroxide. Examples of a reactive aluminosilicate material are Class F fly ash (FFA) and Class C fly ash (CFA).
Fly ash is a fine powder byproduct formed from the combustion of coal. Electric power plant utility furnaces burning pulverized coal produce most of the commercially available fly ashes. These fly ashes comprise mainly of glassy spherical particles, as well as hematite and magnetite, unburned carbon, and some crystalline phases formed during cooling. The structure, composition and properties of fly ash particles depend upon the composition of the coal and the combustion process by which fly ash is formed. American Society for Testing and Materials (ASTM) C618 standard recognizes two major classes of fly ashes for use in concrete: Class C and Class F. All ASTM standards and their specifications described in this disclosure are incorporated by reference in their entirety. Class F fly ash is normally produced from burning anthracite or bituminous coal, whereas Class C fly ash is normally produced from lignite or sub-bituminous coal. The ASTM C618 standard differentiates Class F and Class C fly ashes primarily according to their pozzolanic properties. Accordingly, in the ASTM C618 standard, one major specification difference between the Class F fly ash and Class C fly ash is the lower limit of (SiO2+Al2O3+Fe2O3) in the composition. The lower limit of (SiO2Al2O3+Fe2O3) for Class F fly ash is 70% and that for Class C fly ash it is 50%. Accordingly, Class F fly ashes generally have a calcium oxide content of about 15 wt % or less, whereas Class C fly ashes generally have a higher calcium oxide content (e.g., higher than 15 wt %, such as 20 to 40 wt %). A high calcium oxide content makes Class C fly ashes possess cementitious properties leading to the formation of calcium silicate and calcium aluminate hydrates when mixed with water.
Summary: In contrast to the concrete formed from Ordinary Portland Cement (OPC), a geopolymer concrete can exhibit greater heat-, fire- and acid-resistance."
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We'll leave our excerpts from "United States Patent Application 20120024196 - Tailored Geopolymer Composite Binders for Cement and Concrete Applications" at that, although there is a great deal of detailed info concerning the chemistry of it all in the full Disclosure. The point is, Coal Ash can be used in significant proportions in the blending of a substitute for Portland Cement Concrete (PCC), which concrete substitute, a "geopolymer", is significantly stronger and "can exhibit greater heat-, fire- and acid-resistance" than PCC "formed from Ordinary Portland Cement (OPC)".
Scientists at the Catholic University of America again confirmed those essential facts a few months subsequent, through their additional:
"United States Patent Application: 0120152153 - Geopolymer ... for Ultra High Performance Concrete
Patent US20120152153 - Geopolymer composite for ultra high performance concrete - Google Patents
GEOPOLYMER COMPOSITE FOR ULTRA HIGH PERFORMANCE CONCRETE - The Catholic University of America
Date: June 21, 2012
Inventors: Weilang Gong, et. al., MD and VA
Assignee: The Catholic University of America
Abstract: A geopolymer composite ultra high performance concrete (GUHPC), and methods of making the same, are provided herein, the GUHPC comprising: (a) a binder comprising one or more selected from the group consisting of reactive aluminosilicate and reactive alkali-earth aluminosilicate; (b) an alkali activator comprising an aqueous solution of metal hydroxide and metal silicate; and (c) one or more aggregate.
Claims: A geopolymeric composite ultra high performance concrete (GUHPC) mix, comprising:
(a) a binder comprising one or more selected from the group consisting of reactive aluminosilicate and reactive alkali-earth aluminosilicate;
(b) an alkali activator comprising an aqueous solution of metal hydroxide and metal silicate; and (c) one or more aggregate.
GUHPC mix ... wherein the binder comprises about 10 to 50 wt % of the GUHPC mix; (and) wherein the binder comprises one or more reactive aluminosilicate comprising about 0 to 30 wt % of the GUHPC mix (and) wherein the ... reactive aluminosilicate is ... ultrafine Class F fly ash.
The GUHPC mix ... wherein the GUHPC mix results in a product with a 28-day compressive strength of at least about 10,000 psi.
Background and Field: The present invention relates to geopolymer composite binders for ultra high performance concrete and methods of making and using thereof.
During the last ten years, considerable advances have been made in the development of high-performance, or more recently ultra-high-performance, concretes with Portland cement. Ultra high performance concrete (UHPC) represents a major development step over high performance concrete (HPC), through the achievement of very high strength and very low permeability.
UHPC benefits from being a "minimum defect" material--a material with a minimum amount of defects such as micro-cracks and interconnected pores with a maximum packing density.
Despite performance advantages offered by UHPC, deployment has been slow. There are several possible reasons for this, including lack of a clear financial benefit to manufacturers. As would be expected, the costs of fabricating UHPC components are significantly higher than the costs of manufacturing conventional concrete components. Additionally, the higher cost of constituent materials in UHPC necessarily means that UHPC has a higher per-unit volume cost than conventional and high-performance concretes. Much of the cost of UHPC comes from its steel fiber, superplasticizer, and high purity fumed silica. Ultra-high performance fiber reinforced concrete is generally cured with heat and/or pressure to enhance its properties and to accelerate the hydration reaction of the binder, which also increases manufacturing cost.
The present invention relates to use of geopolymer composite (GC) binders, rather than Portland cement, for Ultra High Performance Concrete (GUHPC) applications.
Summary: One aspect of the present invention provides geopolymeric composite ultra high performance concrete (GUHPC) mix, comprising: (a) a binder comprising one or more selected from the group consisting of reactive aluminosilicate and reactive alkali-earth aluminosilicate; and (b) an alkali activator comprising an aqueous solution of metal hydroxide and metal silicate, and (c) one or more aggregate.
In some embodiments, the binder comprises about 10 to 50 wt % of the GUHPC mix (and) the binder comprises one or more reactive aluminosilicate comprising about 0 to 30 wt % of the GUHPC mix. In some related embodiments, the one or more reactive aluminosilicate is ... ultrafine Class F fly ash."
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Our excerpts, we know, have been overlong, even though we haven't reproduced many of the details included in the full Disclosures concerning blending ratios, additives, aggregate additions, etc.
So, let us briefly, even tersely, summarize:
We can manufacture a Geopolymer Ultra High Performance Concrete - - a stronger, better-performing, more chemically-resistant substitute for Ordinary Portland Cement Concrete - - that contains in it's composition a significant proportion of "Class F fly ash", as we obtain as a byproduct from the use of our abundant, eastern United States, high-quality bituminous Coal in the generation of reliable and affordable electric power.