Abstract:
A facility for manufacturing concrete and a method of operation thereof which allow for the benefits of alkali metal activated fly ash hydraulic cement to be realized, which allow the disadvantages associated therewith to be avoided, which allows widespread implementation of alkali metal activated fly ash hydraulic cement as a low-cost and environmentally-friendly substitute for Portland cement, in whole or in part, in traditional applications, and which enables new applications taking advantage of the superior characteristics of alkali metal activated fly ash cement.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to building materials, and more specifically, to a concrete manufacturing facility and a method of operation thereof. 
       BACKGROUND OF THE INVENTION 
       [0002]    For centuries, cementitious compounds have been used to form solid structures, primarily in construction of buildings, temples, bridges, roads, dams, and the like. The ability of cementitious compounds to form building materials having high strength and durability has led to widespread use of such cementitious building materials, from structures formed on site, such as poured concrete slabs, pads, pillars, beams, walls, and the like, to pre-fabricated modular building materials such as concrete blocks, tiles, and modular wall sections. 
         [0003]    Over time, numerous recipes or formulations for cementitious compounds have been developed. Portland cement is one cementitious compound that has numerous advantages for many applications. Specifically, Portland cement is a hydraulic cement that has an acceptable working time and cures quickly, to a high compressive strength. Portland cement is not, however, without its problems. Portland cement is difficult and costly to manufacture. 
         [0004]    An alternative cement composition uses fly ash, a byproduct of combustion processes, such as those found in power generation. Fly ash alone is a suitable cementitious compound for certain applications, but is not a suitable substitute for Portland cement because it has substantially dissimilar characteristics, such as a much lower compressive strength. In order to produce a hydraulic cement with characteristics similar to Portland cement, alkali metal activators have been utilized, in small amounts, in combination with fly ash to form a much stronger hydraulic cement. When activated in this way, fly ash cements exhibit similar characteristics to a Portland cement, and offer certain other advantages over Portland cement. Specifically, fly ash is an inexpensive material compared to Portland cement, is readily available from local sources, and requires little or no processing. Furthermore, alkali metal activated fly ash hydraulic cement, when cured, can obtain compressive strengths higher than those easily obtainable with Portland cement. 
         [0005]    Despite these advantages of alkali metal activated fly ash hydraulic cement, Portland cement has emerged as the most popular cement for nearly all modern applications. One reason for the widespread use of Portland cement is its ability to be stored in dry form, typically as a powder, and may effectively be stored with aggregate materials intermixed therewith. As a hydraulic cement, all that is required to use the powdered Portland cement, with or without aggregate materials, is the addition of an appropriate amount of water. Alkali metal activated fly ash cement, however, suffers from the disadvantage of degrading over time when stored as a hydraulic cement. 
         [0006]    When alkali metal activated fly ash hydraulic cements are stored in a powdered form, moisture, such as humidity in the ambient air, causes hard prills or granules to form throughout the powder, such as around the alkali metal activator, thereby reducing or negating the beneficial effects of the alkali metal activator on the fly ash material. Specifically, the degradation of alkali metal activated fly ash hydraulic cement due to absorption of moisture causes the compressive strength of the cured cement to fall below acceptable levels, approaching those of fly ash alone, as well as causes other important characteristics to change, such as the working time. Thus, alkali metal activated fly ash hydraulic cements have been unsuccessful in the marketplace due to these shelf-life problems when utilized according to methods of use of Portland cement, as a substitute therefor. 
         [0007]    For various applications, different methods of manufacturing concrete, and thus using the Portland cement contained therein, have been developed for various applications. One such method, typically used for mixing smaller batches of concrete, involves bagging pre-measured amounts of Portland cement and aggregate materials, such as sand and/or stones. The bags may then be stored, shipped, and sold, as necessary, as individual units. A consumer may purchase one of more of the bags, empty the contents thereof into a suitable mixing container, such as a bucket or a wheel barrow, add an appropriate amount of water to the Portland cement, mix to the appropriate consistency and/or homogeneity, and use the mixed concrete product as desired. Such bagged concrete products are well suited for forming small footers or other subterranean foundations, such as for supporting a porch, deck, pole, post, or the like, as well as for patching larger cement structures, such as a driveway, a wall, or the like, and for use in construction of larger structures as a bonding agent, such as a mortar application or the like. 
         [0008]    An alternative method is typically used in ready-mix concrete plants and is more efficient for making larger batches of concrete for larger structures, such as sidewalks or driveways, larger foundations, for walls, or the like. The method involves adding pre-measured amounts of Portland cement, various aggregate materials, and water to a drum of a cement-mixing truck. The drum is rotated to mix the various components of the concrete batch, at least during transportation, and the truck is used to deliver the wet concrete from the ready-mix plant to a remote location for subsequent use during the working time of the cement. 
         [0009]    Another similar alternative method, typically used for manufacturing pre-fabricated and/or modular building materials, such as traditional concrete blocks, aerated concrete blocks, or the like, or for forming prefabricated structure sections for subsequent assembly, is used in a facility similar to a ready-mix plant. The method involves adding pre-measured amounts of Portland cement, various aggregate materials, and water to a large mixer and mixing the material to the desired consistency and/or homogeneity. The mixed concrete is then molded into the finished products, i.e. blocks, pillars, beams, decorative elements, wall-sections, or the like. When the concrete is cured, the production is complete, and the finished products are ready for distribution and use. 
         [0010]    These common methods of using concrete, and the Portland cement contained therein, illustrate why alkali metal activated fly ash hydraulic cements have not heretofore been widely adopted. Specifically, bagged cement products are typically manufactured in a first mixing and bagging facility, and stored there until shipped to a warehouse or other distribution facility. The bags of concrete are again stored until being shipped to a retail facility. Finally, the bags are stored at the retail facility until purchased. Thus, the time between the manufacture of the bagged concrete products and the time when they are purchased and/or used is typically at least a few weeks, and can be as long as a year or more. An alkali metal activated fly ash hydraulic cement based bagged concrete product will degrade more than an acceptable amount in a period of time as short as a few weeks or even a few days. Thus, alkali metal activated fly ash hydraulic cement is not suitable for use in conventional bagged concrete products manufactured and/or used according to conventional methods designed for Portland cement. 
         [0011]    Similarly, concrete manufacture at traditional ready-mix plants, as well as at pre-fabricated concrete product manufacturing facilities, involves storage of the hydraulic cement used therein for long periods of time. Such storage poses no problems when using Portland cement, but alkali metal activated fly ash hydraulic cements will degrade, as discussed above, before they could typically be used. Thus, alkali metal activated fly ash hydraulic cements are unsuitable for use according to conventional methods as a substitute for Portland cement in traditional ready-mix plants, or the like, because of the degradation of the cement during storage. 
         [0012]    Thus, what is needed is a facility for manufacturing concrete that is capable of utilizing alkali metal activated fly ash hydraulic cement, and a method of operation thereof, through which the benefits of alkali metal activated fly ash hydraulic cement may be realized, and through which the disadvantages associated therewith may be avoided. Such a facility and method of operation will allow widespread implementation of alkali metal activated fly ash hydraulic cement as a low-cost and environmentally-friendly substitute, in whole or in part, for Portland cement in traditional applications, and will enable new applications taking advantage of the superior characteristics of alkali metal activated fly ash cement. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    Briefly described, in a preferred embodiment, the present invention overcomes the above-mentioned disadvantages and meets the recognized need for such a facility and method by providing storage means for storing fly ash separate from an alkali metal activator. The fly ash and alkali metal activator are preferably combined after separate storage and/or separate shipment thereof to form an alkali metal activated fly ash hydraulic cement. The storage means may preferably store pre-measured amounts of fly ash separate from pre-measured amounts of one or more alkali metal activators such that combination of the pre-measured amount of fly ash and the pre-measured amount of one or more alkali metal activators forms a hydraulic cement according to a predetermined formulation. One or more aggregate material and/or admixture material, preferably pre-measured, may also be stored, preferably in a pre-mixed concrete mixture with the pre-measured amount of fly ash. 
         [0014]    A ready-mix concrete manufacturing facility preferably includes means for storing fly ash, means for storing an alkali metal activator separate from the fly ash, means for storing a hydraulic cement in dry form separate from the fly ash and separate from the alkali metal activator, means for storing at least one aggregate material, means for conveying a predetermined amount of the fly ash to a mixing means, means for conveying a predetermined amount of the alkali metal activator to the mixing means, means for conveying a predetermined amount of the hydraulic cement to the mixing means, means for conveying a predetermined amount of the at least one aggregate material to the mixing means, and means for conveying a predetermined amount of water to the mixing means. 
         [0015]    A method of operating the ready-mix concrete facility preferably comprises the steps of storing fly ash in a means for storing fly ash, storing an alkali metal activator separate from the fly ash in a means for storing alkali metal activator separate from the fly ash, combining a predetermined amount of the fly ash, a predetermined amount of the alkali metal activator, and a predetermined amount of water, and mixing the predetermined amount of the fly ash, the predetermined amount of the alkali metal activator, and the predetermined amount of the water to form an alkali metal activated fly ash cement. 
         [0016]    A pre-fabricated concrete product manufacturing facility preferably includes means for storing fly ash, means for storing an alkali metal activator separate from the fly ash, means for storing a hydraulic cement in dry form separate from the fly ash and separate from the alkali metal activator, means for storing at least one aggregate material, means for conveying a predetermined amount of the fly ash to a mixing means, means for conveying a predetermined amount of the alkali metal activator to the mixing means, means for conveying a predetermined amount of the hydraulic cement to the mixing means, means for conveying a predetermined amount of the at least one aggregate material to the mixing means, means for conveying a predetermined amount of water to the mixing means, and means for dispensing a concrete mixture mixed in the mixing means. 
         [0017]    A method of operating the pre-fabricated concrete product manufacturing facility preferably comprises the steps of storing fly ash in a means for storing fly ash, storing an alkali metal activator separate from the fly ash in a means for storing alkali metal activator separate from the fly ash, combining a predetermined amount of the fly ash, a predetermined amount of the alkali metal activator, and a predetermined amount of water, mixing the predetermined amount of the fly ash, the predetermined amount of the alkali metal activator, and the predetermined amount of the water to form an alkali metal activated fly ash cement to form a concrete mixture, and dispensing the concrete mixture into a mold. 
         [0018]    A bagging facility preferably includes means for storing fly ash, means for conveying the fly ash to a means for bagging the fly ash, means for storing a hydraulic cement in dry form separate from the fly ash, means for storing at least one aggregate material, means for conveying a predetermined amount of the fly ash to a mixing means, means for conveying a predetermined amount of the hydraulic cement to the mixing means, means for conveying a predetermined amount of the at least one aggregate material to the mixing means, means for dispensing a concrete mixture mixed in the mixing means to a means for bagging the concrete mixture. 
         [0019]    An alkali metal activated fly ash cement product preferably comprises means for storing fly ash, means for storing an alkali metal activator, means for storing a hydraulic cement, and means for storing an aggregate material, wherein the means for storing the alkali metal activator prevents the alkali metal activator from contacting at least one of a humid gas, water, and the fly ash. 
         [0020]    According to its major aspects and broadly stated, the present invention in its preferred form is a means for storing fly ash separate from one or more alkali metal activator to prevent degradation thereof and a method of use of an alkali metal activated fly ash hydraulic cement that prevents degradation thereof. 
         [0021]    According to another aspect of the preferred embodiment, the storage means are incorporated in a ready-mix concrete manufacturing facility to allow the manufacture of an alkali metal activated fly ash hydraulic cement at the ready-mix concrete manufacturing facility; thereby, allowing substitution of some or all Portland cement with alkali metal activated fly ash hydraulic cement in ready-mix concrete applications. 
         [0022]    According to another aspect of the preferred embodiment, the storage means are incorporated in a pre-fabricated concrete product manufacturing facility to allow the manufacture of an alkali metal activated fly ash hydraulic cement at the pre-fabricated concrete product manufacturing facility: thereby, allowing substitution of some or all Portland cement with alkali metal activated fly ash hydraulic cement in pre-fabricated concrete products. 
         [0023]    According to another aspect of the preferred embodiment, the storage means are incorporated in a bagged concrete or bagged cement product to allow the manufacture of an alkali metal activated fly ash hydraulic cement at or near the location where the alkali metal activated fly ash cement is to be used; thereby, allowing substitution of some or all Portland cement in bagged cement or bagged concrete products. 
         [0024]    According to another aspect of the preferred embodiment, the storage means stores the fly ash separate from the alkali metal activator until a time sufficiently close to the time when water is added to avoid substantial degradation of the alkali metal activated fly ash hydraulic cement. 
         [0025]    According to another aspect of the preferred embodiment, the fly ash is mixed with the alkali metal activator to create an alkali metal activated fly ash hydraulic cement no more than approximately 24 hours before water is added to the alkali metal activated fly ash hydraulic cement; more preferably, the fly ash is mixed with the alkali metal activator no more than approximately 12 hours before water is added to the alkali metal activated fly ash hydraulic cement, and most preferably the fly ash is mixed with the alkali metal activator no more than approximately 1 hour before water is added to the alkali metal activated fly ash hydraulic cement, although water may be added as much as approximately 48 hours after the alkali metal activated fly ash hydraulic cement is created. 
         [0026]    According to another aspect of the preferred embodiment, fly ash is mixed with the alkali metal activator no later than approximately 5 hours after water is added to the fly ash; more preferably, the fly ash is mixed with the alkali metal activator no later than approximately 2 hours after water is added to the fly ash, and, most preferably, the fly ash is mixed with the alkali metal activator no later than approximately 1 hour after water is added to the fly ash. 
         [0027]    According to another aspect of the preferred embodiment, the ready-mix manufacturing facility may be integrated into a vehicle to enable manufacture of large batches of alkali metal activated fly ash hydraulic cement on site. 
         [0028]    These and other features, and advantages of the present invention will become more apparent to those ordinarily skilled in the art after reading the following Detailed Description and Claims in light of the accompanying drawing Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    Accordingly, the present invention will be understood best through consideration of, and reference to, the following Figures, viewed in conjunction with the Detailed Description of the Preferred Embodiment referring thereto, in which like reference numbers throughout the various Figures designate like structure and in which: 
           [0030]      FIG. 1  is a perspective view of a ready-mix concrete manufacturing facility according to the present invention; 
           [0031]      FIG. 2  is a flow chart illustrating a method of operation of the ready-mix concrete manufacturing facility of  FIG. 1 ; 
           [0032]      FIG. 3  is a perspective view of a pre-fabricated concrete product manufacturing facility according to the present invention; 
           [0033]      FIG. 4  is a flow chart illustrating a method of operation of the pre-fabricated concrete product manufacturing facility of  FIG. 3 ; 
           [0034]      FIG. 5  is a perspective view of a bagging facility according to the present invention; 
           [0035]      FIG. 6  is a perspective view of a bag according to the present invention; and 
           [0036]      FIG. 7  is a flow chart illustrating a method of operation of the cement bagging facility of  FIG. 5 . 
       
    
    
       [0037]    It is to be noted that the drawings presented are intended solely for the purpose of illustration and that they are, therefore, neither desired nor intended to limit the invention to any or all of the exact details of construction shown, except insofar as they may be deemed essential to the claimed invention. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0038]    In describing preferred embodiments of the present invention illustrated in the Figures, specific terminology is employed for the sake of clarity. The invention, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
         [0039]    In that form of the preferred embodiment of the present invention chosen for purposes of illustration,  FIGS. 1-2  show ready-mix concrete manufacturing facility  100 , including storage means  111 - 119 , conveyor means  121 - 129 , control means  130 , mixing means  140 , scale  150 , and water supply  160 . Storage means  111 , such as in the form of a silo, preferably stores fly ash, such as class C fly ash, class F fly ash, or a combination thereof, and is preferably selectively operable to dispense the fly ash to conveyor means  121  associated therewith, such as a conveyor belt, an auger, a hose, a pipe, or the like, according to control signals from control means  130 . Conveyor means  121  preferably selectively conveys fly ash from storage means  111  to mixing means  140  according to control signals from control means  130 . Scale  150  is preferably operably associated with mixing means  140  so that a weight of the contents of mixing means  140  can be determined. Scale  150  is preferably further operably associated with control means  130  such that an indication of the weight can be sent to control means  130  for use in selectively controlling the dispensing of the fly ash from storage means  111 ; thereby, allowing the desired amount of fly ash to be added to mixing means  140 . Scale  150  preferably likewise indicates amounts of each additional ingredient of a batch added to mixing means  140  such that control means  130  may selectively control the dispensing of such additional ingredients; thereby, allowing the proper formulation of concrete to be attained. 
         [0040]    Storage means  112  preferably stores a first alkali metal activator, such as potassium carbonate, and is preferably selectively operable, according to control signals from control means  130  based on indications from scale  350 , to selectively dispense the first alkali metal activator to conveyor means  122 , operably associated therewith. Conveyor means  122  preferably selectively conveys the first alkali metal activator to mixing means  140  according to control signals from control means  130  based on indications from scale  150 . Storage means  113  preferably stores a second alkali metal activator, such as lithium carbonate, and is preferably selectively operable, according to control signals from control means  130 , to dispense the second alkali metal activator to conveyor means  123 , operably associated therewith. Conveyor means  123  preferably selectively conveys the second alkali metal activator to mixing means  140  according to control signals from control means  130  based on indications from scale  150 . Storage means  114  preferably stores citric acid, and is preferably selectively operable, according to control signals from control means  130 , based on indications from scale  150 , to selectively dispense the citric acid to conveyor means  124 , operably associated therewith. Conveyor means  124  preferably selectively conveys the citric acid to mixing means  140  according to control signals from control means  130  based on indications from scale  150 . 
         [0041]    Storage means  115 - 118  preferably store a hydraulic cement, such as Portland cement, a first aggregate material, such as sand, a second aggregate material, such as gravel, and a third aggregate material, such as stones, respectively. Each of storage means  115 - 118  is preferably operably connected to conveyor means  125 - 128 , respectively, and is preferably selectively operable for dispensing the respective contents thereof to the respective conveyor means  125 - 128  associated therewith according to control signals from control means  130  based on indications from scale  150 . Each of storage means  119   a - 119   e  preferably stores a respective admixture material, such as a plasticizer, a retarder, an accelerator, a water-reducer, a foaming or air-entraining agent, a tint or dye, boric acid, slag, silica, borax, gypsum, sawdust, straw, woodchips, structural fibers, or the like, for selective addition to mixing means  140  according to control signals from control means  130 . 
         [0042]    Thus, control means  130  may preferably control each of storage means  111 - 119  and conveyor means  121 - 129  to deliver predetermined amounts of the contents of storage means  111 - 119  to mixing means  140  to create a batch of material, such as concrete, mortar, or the like, of a desired size, having a desired formulation. Preferably, mixing means  140  substantially homogenizes the dry ingredients of the concrete formulation, and dispenses such substantially homogenous mixture to drum D of mixing truck MT via dispensing means  170 . A predetermined amount of water, based on the selected concrete formulation, is preferably added to drum D via water supply  160 . 
         [0043]    As will be understood by those skilled in the art, storage means  111 - 119  and conveyor means  121 - 129  may be formed from any suitable materials, and may be arranged according to numerous various possible arrangements as needed or desired for any particular implementation or site. Furthermore, storage means  111 - 119  may include additional components as needed or desired, such as vibrators, grinders, aerators, fluidizers, pumps, sprayers, valves, sensors, monitors, scales, metering means, or other like. Additionally, conveyor means  121 - 129  may include additional components as needed or desired, such as covers, valves, sensors, monitors, metering means, or the like. In particular, such additional components may enhance or substitute for the function of one or more elements of ready-mix manufacturing plant  100 . For example, scale  150  may be replaced with alternative or additional scales, flow meters, or other metering means operably associated with each of storage means  111 - 119  or conveyor means  121 - 129  and capable of outputting indications corresponding to an amount of material dispensed to an associated conveyor means or mixing means such that control means  130  is capable of controlling an amount of the respective contents of each storage means added to a particular batch of material. Finally, one or more additional or further storage means may be included, with associated conveyor means, in order to allow additional ingredients to be included in a particular batch of material. Similarly, mixing means  140  may be eliminated and the ingredients of the batch of material may be mixed entirely by drum D of mixing truck MT. Likewise, one or more of conveyor means  121 - 129  may be replaced, eliminated, or modified to convey ingredients from a plurality, or even all, of storage means  111 - 119 . 
         [0044]    In use, ready-mix manufacturing facility  100  is preferably operated according to method  200 . Method  200  preferably begins with step  201 , where batch information, including predetermined information regarding batch size and a specific batch formulation, is preferably entered into control software of control means  130 . The control software preferably determines, at step  203 , whether an ingredient is required according to the batch information. For the necessary ingredient, the control software preferably determines an appropriate amount of the necessary ingredient to be dispensed at step  205 . The control software, at step  207 , preferably activates control means  130  to send appropriate control signals to a corresponding one of storage means  111 - 119  containing the necessary ingredient and to a corresponding one of conveyor means  121 - 129  associated therewith, or to water supply  160 , to automatically dispense an amount of the necessary ingredient substantially equal to the appropriate amount (determined in step  205 ) and to convey the ingredient to mixing means  140  or drum D of mixing truck MT to produce a batch of material according to the batch information. At step  209 , the amount of the necessary ingredient is measured. At step  211 , the measured amount is compared to the appropriate amount. If the measured amount is less than the appropriate amount, the method returns to step  207 . If the measure amount is greater than or equal to the appropriate amount, the software preferably sends a control signal to dispense the measured amount of the ingredient to a mixer, such as mixing means  140  or drum D of mixing truck MT, at step  213 . The method then returns to step  203  and repeats steps  205 - 213  until it is determined at step  203  that no ingredient is required according to the batch information. The process then returns to step  201  and awaits the input of new batch information for a new batch. Thus, ready-mix concrete manufacturing facility  100 , and method  200  of operation thereof, allows for the manufacture of a batch of material, such as concrete, mortar, or the like, according to virtually any formulation, including those calling for alkali metal activated fly ash cement. 
         [0045]    As will be understood by one ordinarily skilled in the art, additional or alternative steps may be included in method  200  without departing from the scope of the invention, so long as fly ash, one or more alkali metal activator, and any other necessary or desired ingredients may be stored such that degradation thereof is prevented. For example, method  200  may include the steps of providing batch information including instructions regarding the formulation of a batch of concrete, cement, mortar, or the like, or information including required or desired performance characteristics of a formulated concrete, cement, mortar, or the like; determining an amount of Portland, or other, hydraulic cement to be substituted with alkali metal activated fly ash cement; and determining an amount of alkali metal activated fly ash cement to be used as a substitute for the Portland, or other, hydraulic cement that will yield a product having substantially similar performance characteristics as a product formulated according to the batch information without any substitutions. Likewise, alternative methods of selecting and metering desired ingredients may be used to combine fly ash, one or more alkali metal activator, and any other necessary or desired ingredient for use as a hydraulic cement at ready-mix concrete manufacturing facility  100 , especially as a substitute, in whole or in part, for Portland cement. 
         [0046]    Now referring to  FIGS. 3-4 , pre-fabricated concrete product manufacturing facility  300  preferably includes storage means  311 - 319 , conveyors  321 - 329 , control means  330 , mixing means  340 , scale  350 , water supply  360 , and dispensing means  370 . Storage means  311 , such as in the form of a silo, preferably stores fly ash, and is preferably selectively operable to dispense the fly ash to conveyor means  321  associated therewith, such as a conveyor belt, an auger, a hose, a pipe, or the like, according to control signals from control means  330 . Conveyor means  321  preferably selectively conveys fly ash from storage means  311  to mixing means  340  according to control signals from control means  330 . Scale  350  is preferably operably associated with mixing means  340  so that a weight of the contents of mixing means  340  can be determined. Scale  350  is preferably further operably associated with control means  330  such that an indication of the weight can be sent to control means  330  for use in selectively controlling the dispensing of the fly ash from storage means  311 , thereby allowing the desired amount of fly ash to be added to mixing means  340 . Scale  350  preferably likewise indicates amounts of each additional ingredient of a batch added to mixing means  340  such that control means  330  may selectively control the dispensing of such additional ingredients, thereby allowing the proper formulation of concrete to be attained. 
         [0047]    Storage means  312  preferably stores a first alkali metal activator, such as potassium carbonate, and is preferably selectively operable, according to control signals from control means  330  based on indications from scale  350 , to selectively dispense the first alkali metal activator to conveyor means  322 , operably associated therewith. Conveyor means  322  preferably selectively conveys the first alkali metal activator to mixing means  340  according to control signals from control means  330  based on indications from scale  350 . Storage means  313  preferably stores a second alkali metal activator, such as lithium carbonate, and is preferably selectively operable, according to control signals from control means  330  based on indications from scale  350 , to dispense the second alkali metal activator to conveyor means  323 , operably associated therewith. Conveyor means  323  preferably selectively conveys the second alkali metal activator to mixing means  340  according to control signals from control means  330  based on indications from scale  350 . Storage means  314  preferably stores citric acid, and is preferably selectively operable, according to control signals from control means  330 , based on indications from scale  350 , to selectively dispense the citric acid to conveyor means  324 , operably associated therewith. Conveyor means  324  preferably selectively conveys the citric acid to mixing means  340  according to control signals from control means  330  based on indications from scale  350 . 
         [0048]    Storage means  315 - 318  preferably store a hydraulic cement, such as Portland cement, a first aggregate material, such as sand, a second aggregate material, such as gravel, and a third aggregate material, such as stones, respectively. Each of storage means  315 - 318  is preferably operably connected to conveyor means  325 - 328 , respectively, and is preferably selectively operable for dispensing the respective contents thereof to the respective conveyor means  325 - 328  associated therewith according to control signals from control means  330  based on indications from scale  350 . Each of storage means  319   a - 319   e  preferably stores a respective admixture material, such as a plasticizer, a retarder, an accelerator, a water-reducer, a foaming or air-entraining agent, a tint or dye, boric acid, slag, silica, borax, gypsum, sawdust, straw, woodchips, structural fibers, or the like, for selective addition to mixing means  340  according to control signals from control means  330 . A predetermined amount of water, based on the selected concrete formulation, is preferably added to mixing means  340  via water supply  360  and is preferably mixed to create a concrete mixture with the desired consistency and homogeneity. 
         [0049]    Thus, control means  330  may preferably control each of storage means  311 - 319  and conveyor means  321 - 329  to deliver predetermined amounts of the contents of storage means  311 - 319  to mixing means  340  to create a desired amount of a concrete material having a desired formulation. Preferably, mixing means  340  substantially homogenizes the dry ingredients of the concrete formulation, the water, and any liquid ingredients (typically the admixtures may be liquid, although other ingredients, such as one or more alkali metal activator and/or the citric acid may be liquid), and dispenses such substantially homogenous mixture to mold M, or other container, for use in manufacturing a pre-fabricated concrete structure or building material via dispensing means  370 . 
         [0050]    As will be understood by those skilled in the art, storage means  311 - 319  and conveyor means  321 - 329  may be formed from any suitable materials, and may be arranged according to numerous various possible arrangements as needed or desired for any particular implementation or site. Furthermore, storage means  311 - 319  may include additional components as needed or desired, such as vibrators, grinders, aerators, fluidizers, pumps, sprayers, valves, sensors, monitors, scales, metering means, or other like. Additionally, conveyor means  321 - 329  may include additional components as needed or desired, such as covers, valves, sensors, monitors, metering means, or the like. In particular, such additional components may enhance or substitute for the function of one or more elements of pre-fabricated concrete product manufacturing facility  300 . For example, scale  350  may be replaced with alternative or additional scales, flow meters, or other metering means operably associated with each of storage means  311 - 319  and conveyor means  321 - 329  and capable of outputting indications of an amount of material dispensed to an associated conveyor means or mixing means such that control means  330  is capable of controlling an amount of the respective contents of each of storage means  311 - 319  added to a particular batch of concrete. Finally, one or more additional or further storage means may be included, with associated conveyor means, in order to allow additional ingredients to be included in a particular batch of concrete. Similarly, one or more of conveyor means  321 - 329  may be replaced, eliminated, or modified to convey ingredients from a plurality, or even all, of storage means  311 - 319 . 
         [0051]    In use, pre-fabricated concrete product manufacturing facility  300  is preferably operated according to method  400 . Method  400  preferably begins with step  401 , where batch information, including predetermined information regarding batch size and a specific formulation of the concrete batch, is preferably entered into control software of control means  330 . The control software preferably determines, at step  403 , whether an ingredient is required according to the batch information. For the necessary ingredient, the control software preferably determines an appropriate amount of the necessary ingredient to be dispensed at step  405 . The control software, at step  407 , preferably activates control means  330  to send appropriate control signals to a corresponding one of storage means  311 - 319  containing the necessary ingredient and to a corresponding one of conveyor means  321 - 329  associated therewith, or to water supply  360 , to automatically dispense an amount of the necessary ingredient substantially equal to the appropriate amount (determined in step  405 ) and to convey the ingredient to mixing means  340  to produce a batch of concrete according to the batch information. At step  409 , the amount of the necessary ingredient is measured. At step  411 , the measured amount is compared to the appropriate amount. If the measured amount is less than the appropriate amount, the method returns to step  407 . If the measure amount is greater than or equal to the appropriate amount, the software preferably sends a control signal to dispense the measured amount of the ingredient to a mixer, such as mixing means  340 , at step  413 . The method then returns to step  403  and repeats steps  405 - 413  until it is determined at step  403  that no ingredient is required according to the batch information. The process then returns to step  401  and awaits the input of new batch information for a new batch. Thus, pre-fabricated concrete product manufacturing facility  300 , and method  400  of operation thereof, allows for the manufacture of a batch of concrete according to virtually any formulation, including those calling for alkali metal activated fly ash cement. 
         [0052]    As will be understood by one ordinarily skilled in the art, additional or alternative steps may be included in method  400  without departing from the scope of the invention, so long as fly ash, one or more alkali metal activator, and any other necessary or desired ingredients may be stored such that degradation thereof is prevented. Likewise, alternative methods of selecting and metering desired ingredients may be used to combine fly ash, one or more alkali metal activator, and any other necessary or desired ingredient for use as a hydraulic cement at pre-fabricated concrete product manufacturing facility  300 , especially as a substitute, in whole or in part, for Portland cement. 
         [0053]    Now referring to  FIGS. 5-7 , bagging facility  500  preferably includes storage means  511 - 517 , conveyors  521 - 527 , control means  530 , mixing means  540 , scale  550 , dispensing means  570 , and bagging means  580 . Storage means  511  such as in the form of a silo, preferably stores fly ash, and is preferably selectively operable to dispense the fly ash to conveyor means  521  associated therewith, such as a conveyor belt, an auger, a hose, a pipe, or the like, according to control signals from control means  530 . Conveyor means  521  preferably selectively conveys fly ash from storage means  511  to mixing means  540  according to control signals from control means  530 . Scale  550  is preferably operably associated with mixing means  540  so that a weight of the contents of mixing means  540  can be determined. Scale  550  is preferably further operably associated with control means  530  such that an indication of the weight can be sent to control means  530  for use in selectively controlling the dispensing of the fly ash from storage means  511 , thereby allowing the desired amount of fly ash to be added to mixing means  540 . Scale  550  preferably likewise indicates amounts of each additional ingredient of a batch of material added to mixing means  540  such that control means  530  may selectively control the dispensing of such additional ingredients, thereby allowing the proper formulation of material to be attained. 
         [0054]    Storage means  512  preferably stores citric acid, and is preferably selectively operable, according to control signals from control means  530 , based on indications from scale  550 , to selectively dispense the citric acid to conveyor means  522 , operably associated therewith. Conveyor means  522  preferably selectively conveys the citric acid to mixing means  540  according to control signals from control means  530  based on indications from scale  550 . 
         [0055]    Storage means  513 - 516  preferably store a hydraulic cement, such as Portland cement, a first aggregate material, such as sand, a second aggregate material, such as gravel, and a third aggregate material, such as stones, respectively. Each of storage means  513 - 516  is preferably operably connected to conveyor means  523 - 526 , respectively, and is preferably selectively operable for dispensing the respective contents thereof to the respective conveyor means  523 - 526  associated therewith according to control signals from control means  530  based on indications from scale  550 . Each of storage means  517   a - 517   e  preferably stores a respective admixture material, such as a plasticizer, a retarder, an accelerator, a water-reducer, a foaming or air-entraining agent, a tint or dye, boric acid, slag, silica, borax, gypsum, sawdust, straw, woodchips, structural fibers, or the like, for selective addition to mixing means  540  according to control signals from control means  530 . 
         [0056]    Thus, control means  530  may preferably control each of storage means  511 - 517  and conveyor means  511 - 517  to deliver predetermined amounts of the contents of storage means  511 - 517  to mixing means  540  to create a desired amount of a material mixture having a desired formulation. Preferably, mixing means  540  substantially homogenizes the fly ash, citric acid, one or more aggregate materials, and any other ingredients, and dispenses such substantially homogenous material mixture to bagging means  580  via dispensing means  570 . Bagging means  580  preferably produces bagged cement product B comprising bag  600  and concrete mixture contained therein. Bag  600  is preferably sealed, such as at top edge  601 , and preferably contains a pre-determined amount, typically by weight, of the concrete mixture. Since bag  600  does not contain any alkali metal activator, bag.  600  prevents degradation of the concrete mixture, and allows bagged cement product B to be stored and/or shipped as needed. 
         [0057]    Sealed container  650  containing one or more alkali metal activator, either in liquid or powder form, is preferably included with bag  600 , sealed thereinside during the bagging process, such as in interior compartment  640 . Sealed container  650  may alternatively be attached to exterior  610  of bag  600 , such as in external compartment  620 , or included at the point of retail sale of bagged cement product B. Sealed container  650  preferably includes a predetermined amount of alkali metal activator appropriate to activate the quantity of fly ash contained in bag  600 . Thus, different sealed containers  650  may contain different amounts and/or formulations of alkali metal activator appropriate for different concrete formulations. Sealed container  650  may additionally contain one or more liquid or powder admixtures, if it is desirable to maintain such admixtures separate from the contents of bag  600 . Furthermore, sealed container  650  may include separate compartments  651  and  652  therewithin for maintaining the alkali metal activator separate from any admixtures, if such separation is necessary to prevent degradation of either. 
         [0058]    As will be understood by those skilled in the art, storage means  511 - 517  and conveyor means  521 - 527  may be formed from any suitable materials, and may be arranged according to numerous various possible arrangements as needed or desired for any particular implementation or site. Furthermore, storage means  511 - 517  may include additional components as needed or desired, such as vibrators, grinders, aerators, fluidizers, pumps, sprayers, valves, sensors, monitors, scales, metering means, or other like. Additionally, conveyor means  521 - 527  may include additional components as needed or desired, such as covers, valves, sensors, monitors, metering means, or the like. In particular, such additional components may enhance or substitute for the function of one or more elements of bagging facility  500 . For example, scale  550  may be replaced with alternative or additional scales, flow meters, or other metering means operably associated with each of storage means  511 - 517  and capable of outputting indications corresponding to an amount of material dispensed to an associated conveyor means or mixing means such that control means  530  is capable of controlling an amount of the respective contents of each of storage means  511 - 517  added to a particular batch of material. Finally, one or more additional or further storage means may be included, with associated conveyor means, in order to allow additional ingredients to be included in a particular batch of material. Similarly, one or more of conveyor means  521 - 527  may be replaced, eliminated, or modified to convey ingredients from a plurality, or even all, of storage means  511 - 517 . 
         [0059]    In use, bagging facility  500  is preferably operated according to method  700 . Method  700  preferably begins with step  701 , where batch information, including predetermined regarding batch size and formulation, is preferably entered into control software of control means  530 . The control software preferably determines, at step  703 , whether an ingredient is required according to the batch information. For the necessary ingredient, the control software preferably determines an appropriate amount of the necessary ingredient to be dispensed at step  705 . The control software, at step  707 , preferably activates control means  530  to send appropriate control signals to a corresponding one of storage means  511 - 517  containing the necessary ingredient and to a corresponding one of conveyor means  521 - 527  associated therewith to automatically dispense an amount of the necessary ingredient substantially equal to the appropriate amount (determined in step  705 ) and convey the ingredient to mixing means  540  to produce a batch of material according to the batch information. At step  709 , the amount of the necessary ingredient is measured. At step  711 , the measured amount is compared to the appropriate amount. If the measured amount is less than the appropriate amount, the method returns to step  707 . If the measure amount is greater than or equal to the appropriate amount, the software preferably sends a control signal to dispense the measured amount of the ingredient to a mixer, such as mixing means  540 , at step  713 . The method then returns to step  703  and repeats steps  705 - 713  until it is determined at step  703  that no ingredient is required according to the batch information. The process then returns to step  701  and awaits the input of new batch information for a new batch. Thus, bagging facility  500 , bag  600 , and method  700  of operation thereof, allows for the manufacture of a pre-mixed and pre-measured cement product according to virtually any formulation, including those calling for alkali metal activated fly ash cement. 
         [0060]    As will be understood by one ordinarily skilled in the art, additional or alternative steps may be included in method  700  without departing from the scope of the invention, so long as fly ash, one or more alkali metal activator, and any other necessary or desired ingredients may be stored such that degradation thereof is prevented. Likewise, alternative methods of selecting and metering desired ingredients may be used to combine fly ash and any other necessary or desired ingredient and a separately stored alkali metal activator for subsequent storage and/or shipment thereof as a substitute, in whole or in part, for bagged Portland cement products by combining the separate alkali metal activator and the bagged material mixture to form a hydraulic cement and adding an appropriate amount of water thereto. 
         [0061]    While nearly any formulation of cement, concrete, mortar, or the like may be manufactured according to the present invention, the preferred formulation comprises fly ash and an alkali metal activator. Additionally, the formulation may further comprise one or more additional hydraulic cement, such as Portland cement, one or more aggregate material, and/or one or more admixture material. The formulation may be selected to include, by weight, 15% to 89.9% Class C fly ash, 0.1% to 4.2% Potassium Carbonate, 0% to 5% Citric Acid, and 10% to 84.9% type I Portland cement. An alternative formulation may be selected to include, by weight, 35% to 89.9% Class C fly ash, 0.1% to 4.2% Potassium Carbonate, 0% to 3% Lithium Carbonate, 0% to 5% Citric Acid, and 10% to 64.4% type I Portland cement. Exemplary formulations include the following formulations. 
       EXAMPLE 1 
     EXAMPLE 2 
     EXAMPLE 3 
     EXAMPLE 4 
       [0062]    Although the storage means of the present invention have been illustrated, for exemplary purposes, in the form of one or more silos, it will be understood that such storage means may take other forms, such as bins, boxes, bottles, tanks, bags, hoppers, piles, trucks, containers, combinations thereof, or the like, without departing from the scope of the present invention. Similarly, the conveyor means of the present invention may take the form of belts, tubes, pipes, shafts, augers, pumps, blowers, gears, scoops, sprayers, shovels, combinations thereof, or the like, without departing from the scope of the present invention. Likewise, the mixing means of the present invention may take the form of vibrators, agitators, augers, gears, paddles, tumblers, drums, sifters, grinders, blenders, buckets, wheel barrows, combinations thereof, or the like, without departing from the scope of the present invention. 
         [0063]    Having, thus, described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifications may be made within the scope and spirit of the present invention. Accordingly, the present invention is not limited to the specific embodiments as illustrated herein, but is only limited by the following claims.