Patent Application
20250012019
In some aspects, the present technology relates to a systems, mixtures and methods for use in connection with producing paying products from recycled material. In some other aspects, the present technology relates to systems or methods associated with preparing paving blocks comprising a mixture of recycled asphalt shingles (RAS) and recycled asphalt pavement (RAP) particles.
Without limiting the scope of the present technology, its background is described in connection with materials and methods for producing paving blocks. More particularly, the present technology describes mixtures and methods for using thereof to mold various paving blocks.
Up to 11 million tons of post-consumer asphalt shingle waste is generated annually in North America. A portion of this is processed into RAS (recycled asphalt shingle, which is a powder-like substance resulting from decontamination and grinding of shingles) and diverted successfully into use as a dust suppressant on gravel roads and parking lots, and as an additive in hot mix asphalt. But these uses have significant limitations (low value in the case of dust suppressant, and road specifications issues in the case of hot mix asphalt), and much of the post-consumer asphalt shingle waste ends up being land-filled. Further, up to 4 million tons of post-consumer asphalt flat roofing is generated annually in North America, and most or all of this is currently landfilled. An alternative market as a material for use in forming paving blocks could raise the value of RAS and lead toward greater diversion of post-consumer asphalt shingle waste from landfills; similarly, this same market could lead toward the diversion of post-consumer asphalt flat roofing waste from landfills.
A close analog of RAS is RAP (recycled asphalt pavement, which is a gravel-like substance resulting from the milling of road surfaces or the crushing of broken asphalt pavement). Like RAS, RAP is used as an additive in hot mix asphalt, and in fact, is used much more extensively than RAS there. The proportion of RAP that is not used in hot mix asphalt has a lower value use as a gravel substitute, and so waste asphalt pavement is seldom land-filled. However, an alternative market as a material for use in forming paving blocks could raise the value of RAP and lead to a greater proportion of it being used in a higher value use than as a gravel substitute.
Asphalt cement (a form of bitumen) is present in both RAS and RAP. It is the binder still present in both materials. RAS typically has a range of 18-24% asphalt cement, whereas RAP has a much lower asphalt cement content, in the range of 5-6%. Asphalt cement is normally the most expensive material in the manufacture of roofing materials or hot mix asphalt, even at the low percentage of 5-6%, and so a recycling use that is able to harness the binder quality of post-consumer asphalt cement may be optimal with relation to material value.
The prior art fails to disclose the use of RAS and RAP, along with heat and pressure, as a basis for producing paving blocks. The need exists, therefore, for an improved method and improved components to be used for producing more durable paving blocks.
Accordingly, it is an object of the present technology to overcome these and other drawbacks of the prior art by providing a novel mixture for producing paving blocks.
It is another object of the present technology to provide a novel method of forming paving blocks using the mixture of the present technology.
It is a further object of the present technology to provide methods of increasing the use of recycled materials in preparing paving blocks.
The present technology provides a mixture for producing paving products comprising recycled asphalt shingles (RAS) and recycled asphalt pavement (RAP) particles. The use of these components to form a resulting composite material provides a material that has considerable strength and durability, and absorbs a minimal amount of water, therefore making it nearly impervious to damage caused by the freeze/thaw cycle.
Further, the present technology provides a molded paving block using a mixture for producing paving products comprising RAP and RAS particles that are to be used to construct roads, parking lots, driveways, floors, and the like. The molded paving blocks of the present technology are to be used substantially in the same manner as presently available interlocking blocks.
The materials used are preferably recycled materials such as RAS and RAP. However, aggregate, whether virgin aggregate or recycled rock-like materials such as crushed glass, crushed concrete, crushed rubble, crushed seashells, sand tailings, et cetera, may be substituted or partially substituted for the RAP. There are many advantages to using recycled materials, such as the reduction of waste and lower cost of raw materials.
In some embodiments, proportional amounts of materials in the composite material include RAP in a proportion of about 35% by mass, RAS in a proportion of about 30% by mass, rock-like material that is not RAP in a proportion of about 25% by mass, and hard surfacing material in a proportion of about 10% by mass.
In some embodiments, proportional amounts of materials in the composite material include RAP in a proportion of about 60% by mass, RAS in a proportion of about 25% by mass, rock-like material that is not RAP in a proportion of about 10% by mass, and hard surfacing material in a proportion of about 5% by mass.
The RAP should generally be the main or prevalent constituent of the composite material that forms the composite block of the present technology. However, the RAS, although generally a secondary constituent of the composite material, is of equal importance to the RAP because it contains a much higher percentage of the binder, asphalt cement, than does the RAP. The RAP (and other aggregates) provides the compressive strength and abrasion resistance of the composite material, whereas the RAS provides most of its cleavage strength and resistance to water absorption. The two together make a far superior paver than could be made with either alone.
Further, the present technology provides a process for manufacturing molded paving blocks, comprising the steps of heating and molding RAS and RAP into a molded paving block.
According to one aspect, the present technology relates to a method of manufacturing one or more paving blocks using a mixture. The method can include the following steps:
According to another aspect, the present technology relates to a method of manufacturing one or more paving blocks using a mixture. The method can include the following steps:
In some embodiments, the pressure can be at or above 800 pounds per square inch.
Some embodiments of the present technology can include a step of mixing rock-like material that is not recycled asphalt pavement in with the recycled asphalt shingle particles and recycled asphalt pavement particles to produce a homogenous mixture in step (a).
Some embodiments of the present technology can include a step of placing hard surfacing material into the molding system prior to the step of distributing the heated mixture into a molding system.
In some embodiments, the heating of the homogenous mixture can be conducted in a transfer device that performs the step of distributing the heated mixture or transferring the homogenous mixture to the molding system.
In some embodiments, the transfer device can be an auger system configured to heat the mixture traveling therethrough.
In some embodiments, the auger system can include:
In some embodiments, the auger system can include an auger rotatably received in the inner chamber and configured to advance the homogenous mixture along a longitudinal length of the auger system.
In some embodiments, the auger system can include one or more vents extending through the outer chamber to fluidly communicate the inner chamber with an outside of the outer body.
In some embodiments, the outer chamber can be configured to receive a heated fluid to heat the homogenous mixture traveling through the inner chamber.
In some embodiments, the outer chamber can include a helical baffle located between the outer body and the inner body. The helical baffle can be configured to circulate the heated fluid as it travels through the outer chamber.
In some embodiments, the outer chamber can be separated into a first outer chamber and a second outer chamber. The first outer chamber can receive a first heated fluid at a first temperature, and the second outer chamber can receive a second heated fluid at a second temperature greater than the first temperature.
Some embodiments of the present technology can include a step of distributing the heated mixture into compartments of the molding system.
In some embodiments, the molding system can include an actuator configured to move the paving blocks out from the molding system.
In some embodiments, the molding system can be an extruder configured to produce a continuous paving block.
Some embodiments of the present technology can include a step of cutting the continuous paving block into the paving blocks.
According to another aspect, the present technology can include a mixture for producing paving products comprising recycled asphalt pavement particles in the amount of 20 to 90 percent of the mixture by weight, and recycled asphalt shingle particles.
According to still another aspect, the present technology can include a paving block produced using a mixture comprising recycled asphalt pavement particles in the amount of 20 to 80 percent of the mixture by weight, and recycled asphalt shingle particles.
According to yet another aspect, the present technology can include a method of manufacturing a paving block using a mixture comprising recycled asphalt pavement particles in the amount of 20 to 90 percent of the mixture by weight, and recycled asphalt shingle particles. The method can include the steps of:
In some embodiments, the amount of recycled asphalt shingle particles can be from 5 to 80 percent of the mixture by weight, or can be from 10 to 40 percent of the mixture by weight.
Some embodiments of the present technology can include a rock-like material that is not recycled asphalt pavement.
In some embodiments, the amount of rock-like material that is not recycled asphalt pavement can be from 5 to 50 percent of the mixture by weight.
In some embodiments, the rock-like material that is not recycled asphalt pavement can be selected from a group consisting of virgin rock such as sand and gravel or recycled rock-like materials such as crushed glass, crushed concrete, crushed rubble, crushed seashells et cetera.
Some embodiments of the present technology can include a hard surfacing material.
In some embodiments, an amount of hard surfacing can be from 2 to 15 percent of the mixture by weight.
In some embodiments, the hard surfacing material can be selected from a group consisting of rocks, pieces of metal, synthetic rocks, or a mix thereof.
In some embodiments, the mixture can contain at least 20 percent by weight of the recycled asphalt shingle particles, at least 25 percent by weight of the recycled asphalt pavement particles, at least 15 percent by weight of the rock-like material that is not recycled asphalt pavement, and at least 2 percent by weight of the hard surfacing material.
In some embodiments, no recycled asphalt pavement particle or recycled asphalt shingle particle or rock-like material particle that is not recycled asphalt pavement is larger than 1 inch, and no hard surfacing material particle is larger than ⅜ of an inch.
In some embodiments, the paver can be characterized by being able to withstand a compressive force of at least 800 pounds per square inch and allowing no more than 4% water absorption.
In some embodiments, the first pressure can be at or above 800 pounds per square inch.
In some embodiments, the second pressure can be at or above 800 pounds per square inch.
In some embodiments, the method step (d) can be accomplished using a continuous feed oven with a traveling belt.
Some embodiments of the present technology can include a step of mixing rock-like material that is not recycled asphalt pavement in with the recycled asphalt shingle particles and recycled asphalt pavement particles to produce a homogenous mixture in step (a).
Some embodiments of the present technology can include a step of positioning a hard surfacing material into the primary molding system prior to performing step (b).
Some embodiments of the present technology can include a step of positioning a hard surfacing material into the secondary molding system prior to performing step (e).
According to still another aspect, the present technology can include a method of manufacturing paving blocks using a mixture comprising recycled asphalt pavement particles in the amount of 20 to 80 percent of the mixture by weight, and recycled asphalt shingle particles. The method can include the steps of:
In some embodiments, the pressure in step (d) can be at or above 800 pounds per square inch.
Some embodiments of the present technology can include a step of mixing rock-like material that is not recycled asphalt pavement in with the recycled asphalt shingle particles and recycled asphalt pavement particles to produce a homogenous mixture in step (a).
Some embodiments of the present technology can include a step of placing hard surfacing material into the compartments of the molding system prior to step (c).
According to still yet another aspect, the present technology can include a method of manufacturing paving blocks using a mixture comprising recycled asphalt pavement particles in the amount of 20 to 80 percent of the mixture by weight, and recycled asphalt shingle particles. The method can include the steps of:
In some embodiments, the pressure in step (c) can be at or above 800 pounds per square inch.
Some embodiments of the present technology can include a step of filling compartments of a molding system with recycled asphalt shingle particles and recycled asphalt pavement particles and rock-like material that is not recycled asphalt pavement in a manner that causes a homogenous mixture thereof to be formed in each compartment thereof in step (a).
Some embodiments of the present technology can include a step of placing hard surfacing material into the compartments of the molding system prior to step (a).
According to yet still another aspect, the present technology can include a method of manufacturing paving blocks using a mixture comprising recycled asphalt pavement particles in the amount of 20 to 80 percent of the mixture by weight, and recycled asphalt shingle particles. The method can include the steps of:
In some embodiments, the pressure in step (b) can be at or above 800 pounds per square inch.
In some embodiments, the pressure in step (e) can be at or above 800 pounds per square inch.
Some embodiments of the present technology can include a step of filling compartments of a primary molding system with recycled asphalt shingle particles and recycled asphalt pavement particles and rock-like material that is not recycled asphalt pavement in a manner that causes a homogenous mixture thereof to be formed in each compartment thereof in step (a).
Some embodiments of the present technology can include a step of placing hard surfacing material into the compartments of the primary molding system prior to step (a).
Some embodiments of the present technology can include a step of placing hard surfacing material into the compartments of the secondary molding system prior to step (d).
In some embodiments, step (c) can be accomplished using a continuous feed oven with a traveling belt.
In one embodiment of the present technology, the RAS and RAP are placed into a pugmill to be blended into a composite material; this composite material is molded in a press into a preform, and the preform is then heated in a conveyor oven to about 400 degrees Fahrenheit (F) and afterward, the heated preform is molded into a molded paving block in a second press.
In another embodiment of the present technology, the RAS and RAP are placed into a pugmill to be blended into a composite material, and the composite material is conveyed in a heated auger that heats the composite material to about 400 degrees F. and deposits the heated composite material into a press where it is molded into a molded paving block.
In another embodiment of the present technology, the RAS and RAP are molded in a press heated to about 400 degrees F. into a molded paving block.
In yet another embodiment of the present technology, the RAS and RAP are molded in a press into a preform, the preform is heated in a conveyor oven to about 400 degrees F., and then the heated preform is molded into a molded paving block in a second press.
There has thus been outlined, rather broadly, features of the present technology in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
Numerous objects, features and advantages of the present technology will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of the present technology, but nonetheless illustrative, embodiments of the present technology when taken in conjunction with the accompanying drawings.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present technology. It is, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present technology.
It is therefore an object of the present technology to provide new and novel mixtures and methods for producing paying products that has all of the advantages of the prior art mixtures and methods and none of the disadvantages.
It is another object of the present technology to provide a new and novel mixtures and methods for producing paying products that may be easily and efficiently manufactured and marketed.
An even further object of the present technology is to provide a new and novel mixtures and methods for producing paying products that has a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such mixtures and methods for producing paying products economically available to the buying public.
Still another object of the present technology is to provide a new mixtures and methods for producing paying products that provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
These together with other objects of the present technology, along with the various features of novelty that characterize the present technology, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the present technology, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated embodiments of the present technology. Whilst multiple objects of the present technology have been identified herein, it will be understood that the claimed present technology is not limited to meeting most or all of the objects identified and that some embodiments of the present technology may meet only one such object or none at all.
Subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through the use of the accompanying drawings, in which:
The same reference numerals refer to the same parts throughout the various figures.
While the known methods and devices fulfill their respective, particular objectives and requirements, the aforementioned devices or systems do not describe mixtures and methods that allows for producing paving products from recycled asphalt shingles (RAS) and recycled asphalt pavement (RAP) particles.
A need exists for a new and novel mixtures and methods that can be used for producing paving products from recycled asphalt shingles (RAS) and recycled asphalt pavement (RAP) particles. In this regard, the present technology substantially fulfills this need. In this respect, the mixtures and methods according to the present technology substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of producing paving products from recycled asphalt shingles (RAS) and recycled asphalt pavement (RAP) particles.
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular embodiments, procedures, techniques, etc. in order to provide a thorough understanding of the present technology. However, it will be apparent to one skilled in the art that the present technology may be practiced in other embodiments that depart from these specific details.
The following description sets forth various examples along with specific details to provide a thorough understanding of claimed subject matter. It will be understood by those skilled in the art, however, that claimed subject matter may be practiced without one or more of the specific details disclosed herein. Further, in some circumstances, well-known methods, procedures, systems, components and/or circuits have not been described in detail in order to avoid unnecessarily obscuring claimed subject matter. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
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Pug mill mix augers or blades 506 blend the RAS, RAP, and rock-like material that is not RAP together into the composite material, which can then be discharged through pug mill metered discharge hopper 508. The composite material is metered proportionally by mass from hopper 508 into heated auger 116 below. Heated auger 116 heats the composite material to about 400 degrees F. as it draws it toward chute 128.
In some embodiments, the hopper 508 can be omitted and the auger 116 can receive the composite material directly or can be integrally associated with a bottom section of the pug mill 502.
The heated auger 116 deposits the heated composite material onto chute 128, while a mold press ram 516 is in a raised position, and the heated composite material slides down chute 128 into a mold press 510. Mold press ram 516 applies pressure to the material in mold press mold 512 to effect the compaction of the material into a molded paving block 10. An actuator 514 located near a bottom of the mold press mold 512 is operated to push the molded paving block 10 out from the mold press mold 512 and onto a conveyor 119. The actuator 514 can be operated while the mold press ram 516 is in the raised or lowered position. Conveyor 119 conveys the molded paving block 10 some distance for cooling.
In some embodiments, the mold press 510 can include the mold press floor 162 and actuator in place of the actuator 514 to move the mold press floor 162 out of the way to allow mold press ram 516 to press the molded paving block 10 down onto conveyor 119 below.
In one or more embodiments, there can be a fourth metered load hopper 105, which is for the hard surface material. Metered load hopper 105 is loaded with a machine such as a front-end loader or a skid steer. If hard surface material is being used, then mold press mold 512 is loaded first with the hard surface material, which is metered proportionally by mass from hopper 105 onto chute 125 and from there slides into mold press mold 512, then the material is deposited into the mold press mold 512 by chute 128 so the material is on top of the hard surface material.
Reference will now be made to
Pug mill mix augers or blades 506 blend the RAS, RAP, and rock-like material that is not RAP together into the composite material, which can then be discharged through pug mill metered discharge hopper 508. The composite material is metered proportionally by mass from hopper 508 into heated auger 116 below. Heated auger 116 heats the composite material to about 400 degrees F. as it draws it toward chute 128.
The heated auger 116 transfers the heated composite material to an extruder 602 that compresses the composite material and forces it through an extruder die 604 having a paving block shape. The extruder 602 creates a continuous flow of the composite material through the extruder die 604 to form a continuous paving block 12 that exits the extruder 602 and onto to a conveyor 119. The extruder die 604 can be removable and interchangeable with other dies of different configurations, allowing different continuous paving blocks 12 to be formed.
A slicing or cutting mechanism 606 can be utilized with the extruder die 604 or the conveyor 119 to cut the continuous paving block 12 into separate paving blocks 10. Conveyor 119 conveys the cut paving blocks 10 some distance for cooling.
Referring to
A spiral or helical baffle 624 can be located in the outer chamber 622 allow for optimal heat transfer from the heated fluid traveling through the outer chamber 622 to the inner chamber 634.
A heater 650 can be utilized to heat the fluid in a controllable manner, and to circulate the fluid to and from the outer chamber 622. It can be appreciated that the heater 650 includes any and all appropriate components to provide heat to the fluid, to receive the fluid, to output the fluid and to circulate the fluid. The heater 650 can include a computer control system, along with any required sensors and/or communication components.
The heated fluid can be, but is not limited to, an oil, water or any liquid capable of transferring heat to the inner chamber 634. In some embodiments, an oil can be used as the heated fluid as it has a delta T (ΔT) than other heating systems such as a furnace burning natural gas. The greater delta T of the furnace may overheat the composite material traveling through the auger 116, and this overheating can release volatiles which is required for binding of the composite material during the pressing process in making the paver block. Accordingly, the use the heater 650 to controllably heat the oil allows for an optimum heat transfer to the composite material traveling through the inner chamber 634, while not overheating the composite material and thereby retaining the volatiles in the composite material for assisting in the binding processes.
In some embodiments, other mechanisms to heat the inner chamber 634 can be utilized in place of or in combination with the heated fluid such as, but not limited to, recovered flue exhaust gas, a furnace, geothermal, solar, an electrical heater, electromagnetic heating, radio-frequency (RF) heating, and the like.
An input 626 can be associated with a discharge end of the outer cylindrical body 620 for providing the heated fluid from the heater 650 to the outer chamber 622. An output 628 can be associated with a receiving end of the outer cylindrical body 620 for exiting the now cooler heated fluid from the outer chamber 622 for transfer back to the heater 650.
A receiving and output section of the heater 650 that receives the cooled heated fluid from and outputs the heated fluid to the outer cylindrical body 620 can be at a height greater than a height of the input 626 and the output 628. This elevated height of the heater 650 can be utilized to control a level of the fluid, to remove any air in the fluid, and/or to prevent flooding of the heater 650.
One or more vents 630 can pass through the outer cylindrical body 620, through the outer chamber 622, and through the inner cylindrical body 632 so as to be in communication with the inner chamber 634. The vents 630 can be configured to allow steam or other gases to escape the inner chamber 632, which may have been released from the composite material heated by the heated fluid. The vents 630 can include a screen, mesh or collection system for filtering and/or capturing the escaping steam and/or gases.
An auger device 636 is rotatably received in the inner chamber 634, and in the exemplary can be operatively associated with a gear/pulley 638 that can be driven by a chain, belt or gear 640, which be driven by a motor 642.
The pug mill 502 or any other mixing hopper can be positioned near the receiving end of the outer cylindrical body 620 to deliver the mixed composite material into the inner chamber 632 for transfer therethrough by the auger device 636.
A discharge nozzle or fitting 642 can be removably attached to the discharge end of the outer cylindrical body 620. This can be accomplished by a flange 644 that can be fastened to the discharge end. The discharge fitting 642 including a hollow interior in communication with the inner chamber 634, and configured to receive the heated composite material exiting the inner chamber 634 and the auger device 636. The discharge fitting 642 can be configured to guide the exiting heated composite material into any one of or any combination of the preform press 140, the mold press 160, the mold press 510, and the extruder 602.
The auger 116 can be supported on a base 654 by one or more support arms 656, thereby making the auger 116 transportable.
Referring to
The output 628 can be associated with the receiving end of the outer cylindrical body 620 for exiting the now cooler first heated fluid from the outer chamber 622 for transfer back to the heater 650.
The second stage heating section can be between the first stage heating section and the discharge end of the outer cylindrical body 620 including the discharge fitting 642. The second stage heating section can be defined by a baffle or stop wall 650 located between the outer cylindrical body 620 and the inner cylindrical body 632, thereby sealing and separating the outer chamber 622 and a second stage outer chamber 652 of the second stage heating section.
A second stage input 656 can be associated with the discharge end of the outer cylindrical body 620 that defines the second stage outer chamber 652 for providing the second heated fluid from the heater 650 to the second stage outer chamber 652. A second stage output 654 can be associated with an end of the second stage outer chamber 652 adjacent to the stop wall 650 for exiting the now cooler second heated fluid from the second stage outer chamber 652 for transfer back to the heater 650.
A second stage helical baffle 654 can be utilized in the second stage outer chamber 652 to provide optimum heat transfer of the second heated fluid to the composite material flowing past the second stage heating section of the alternate auger 116′.
The heater 650 can be configured to separately and independently heat the first and second fluids, and to provide separate and independent circulation of the first and second fluids to and from their corresponding outer chambers 622, 652.
Referring to
A second discharge nozzle or fitting 672 can be removably attached to the discharge end of the second heating section 660. The second discharge fitting 672 can include a hollow interior in communication with the second stage inner chamber 666, and configured to receive the heated composite material exiting the second stage inner chamber 666 and the auger device 636. The second discharge fitting 672 can be configured to guide the exiting heated composite material into any one of or any combination of the preform press 140, the mold press 160, the mold press 510, and the extruder 602.
In some embodiments, the extruder 602 and the auger 636 can be combined into a single unit. The auger 636 section can include an end section that has an auger blade compressing section that is configured to compress the heated composite material against the discharge end. The discharge fitting 642 can include or can be replaced with an extruder die. In operation, a first section of the auger 636 can be configured to transfer the composite material through the heated section of the auger system 116. While a compressing section of the auger 636 can be configured to increasingly compress the heated composite material at or above 800 pounds per square inch, while still transfer it toward the discharge end and thus against the extruder die. The compressed and heated composite material would then be pressed against the extruder die for shaping the composited material into a desired continuous shaped paving block, which can then be cut into preferred length blocks.
In some embodiments, the RAP material of the present technology can be or can include sand tailings, which is a byproduct from oil sands extraction process—a byproduct of separating bitumen from clay, sand and silt using high volumes of water and chemicals. Sand tailings can be a mixture of water, sand, fine silts, clay, residual bitumen and lighter hydrocarbons, inorganic salts and water-soluble organic compounds. Tailings are typically stored in basins called tailings ponds, which allow the solids in tailings to settle, or they can be recovered from ponds and piled. The present technology can first dry the sand tailings RAP to a moisture content of no more than 10%, and preferable no more than 5%. In some embodiments, already dried sand tailings can be obtained and processed into RAP with subsequent drying if required. Then the sand tailings RAP can be added to the mill or mixing hopper prior to entry into the heated auger. The use of sand tailings as RAP solves an ecological problem associated with tailing ponds and large piles of sand tailings that release hazardous chemicals into the atmosphere and/or into surrounding bodies of water. The bitumen content of the sand tailings RAP could also increase the binding properties of the composite material when pressed into the paving blocks.
With regard to all of the processes shown, although the drawings show only a single compartment in the molding systems depicted, all of the molding systems may comprise a single compartment or multiple compartments; and likewise with the support apparatus for each molding system.
With regard to certain of the processes shown, there are various ways of loading the heated preform from the continuous feed oven into the mold press, including, among others, manual loading, loading via the robotic arm, and loading via mechanically guided dropping. Mold press side door 161 and chute 129 are shown for simplicity.
With regard to certain of the processes shown, the heated preform should be appreciably shorter and thinner than mold press mold 163 so as to ease loading into mold press mold 163.
With regard to all processes shown, it is possible to preheat the RAS and RAP prior to depositing them into hoppers 101 and 102, respectively. Working with the RAS while it is below the temperature of 100 degrees F. and RAP while it is below the temperature of 140 degrees F. is advantageous for two reasons. The first reason is that these materials do not adhere badly to the equipment when they are below these temperatures, whereas they do adhere once they are warmed above these temperatures. Such adherence causes ongoing maintenance issues with the equipment, including the need for frequent cleaning and the need to shutdown to clear out components to avoid the risk of them requiring intensive de-gumming. The other reason is that heating RAS and RAP releases volatile organic compounds from any heated surface area. The release of these volatile organic compounds causes noxious odors that must be controlled and also reduces the binder quality of the asphalt cement in the RAS and RAP. So keeping the RAS and RAP below these threshold temperatures prior to the molding of the preform, at which point the surface area of the RAS and RAP is minimized to the surface area of the preform, is far better than heating the RAS and RAP appreciably prior to molding the preform.
With regard to certain of the processes shown, although a pug mill is shown as the blending device, there are many other adequate types of blending devices that can be used instead of a pug mill.
With regard to all processes shown, the RAS, RAP, and rock-like material that is not RAP have preferably been screened such that all pieces are of a size under 1″ in any dimension.
With regard to all processes shown, the hard surface material has preferably been screened such that all pieces are of a size under ⅜″ in any dimension.
With regard to all processes shown, it has been found that a temperature of about 250 degrees F. to about 425 degrees F., and particularly a temperature of about 350 degrees F. to about 400 degrees F., is useful in providing the proper heat for producing a molded paving block with the desired level of compressive strength and resistance to water absorption.
With regard to all processes shown, the proportional mix of RAS and RAP is important. The RAP (or rock-like material that is not RAP) provides the compressive strength and abrasion resistance of the composite material, whereas the RAS provides most of its cleavage strength and resistance to water absorption. The two together make a far superior paver than could be made with either alone. However, in an instance where the objective is to use as much RAS as possible, the proportion of RAP can be reduced. Although such RAP reduction could be taken even to the point of elimination, the loss of compressive strength becomes significant enough that the molded paving blocks produced would be unsuitable for anything other than walking paths. If the RAS component exceeds 50% then the compressive strength is essentially provided by the binder, and the aggregate is superfluous.
With regard to all processes shown, although rock-like material that is not RAP can replace RAP entirely, there is good reason to use some portion of RAP. This is because RAP is already coated with asphalt cement, whereas rock-like material that is not RAP is not coated with asphalt cement; this results in the RAS binding more easily with RAP than with rock-like material that is not RAP. When rock-like material that is not RAP is used, the asphalt cement in the RAS is absorbed to a greater degree into the rock-like material that is not RAP, thus requiring one or more of a higher percentage of RAS, higher pressure, or more dwell time in the oven.
It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method of the present technology, and vice versa. It will be also understood that particular embodiments described herein are shown by way of illustration and not as limitations of the present technology. The principal features of this present technology can be employed in various embodiments without departing from the scope of the present technology. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this present technology and are covered by the claims.
All publications and patent applications mentioned in the specification are indicative of the level of skill of those skilled in the art to which this present technology pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Incorporation by reference is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein, no claims included in the documents are incorporated by reference herein, and any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.
The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.
As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. In embodiments of any of the compositions and methods provided herein, “comprising” may be replaced with “consisting essentially of” or “consisting of”. As used herein, the phrase “consisting essentially of” requires the specified integer(s) or steps as well as those that do not materially affect the character or function of the claimed present technology. As used herein, the term “consisting” is used to indicate the presence of the recited integer (e.g., a feature, an element, a characteristic, a property, a method/process step or a limitation) or group of integers (e.g., feature(s), element(s), characteristic(s), properties(s), method/process steps or limitation(s)) only.
The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.
As used herein, words of approximation such as, without limitation, “about”, “substantial” or “substantially” refers to a condition that when so modified is understood to not necessarily be absolute or perfect but would be considered close enough to those of ordinary skill in the art to warrant designating the condition as being present. The extent to which the description may vary will depend on how great a change can be instituted and still have one of ordinary skilled in the art recognize the modified feature as still having the required characteristics and capabilities of the unmodified feature. In general, but subject to the preceding discussion, a numerical value herein that is modified by a word of approximation such as “about” may vary from the stated value by at least ±1, 2, 3, 4, 5, 6, 7, 10, 12, 15, 20 or 25%.
All of the devices and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the devices and methods of this present technology have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the devices and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the present technology. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the present technology as defined by the appended claims.
This application is a continuation-in-part under 35 U.S.C. § 120 based upon co-pending U.S. patent application Ser. No. 18/120,327 filed on Mar. 10, 2023, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18120327 | Mar 2023 | US |
| Child | 18828049 | US |
