Patent Publication Number: US-9834895-B2

Title: Systems and methods for mixing an asphalt composition

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/474,634, filed May 17, 2012, which is based on and claims priority to U.S. Provisional Application Ser. No. 61/486,801 filed May 17, 2011, the entire contents of which are herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     Aspects of the systems and methods disclosed herein relate to a real-time monitoring and metering of at least one component in a constant flow process for manufacturing asphalt. 
     BACKGROUND 
     In order to minimize costs and the resources necessary to produce new asphalt, recycled asphalt pavement (RAP) may be processed to retrieve aggregate material and asphalt cement or asphalt oil contained therein. In addition, asphalt shingles that make up a significant portion of residential roofing materials may also be recycled to produce new asphalt. During the recycling process, some portion of the RAP and the recycled shingles may be recovered as an aggregate material or as asphalt oil. 
     During the recycling process, the oil content retrieved from the recycled material is not always uniform; therefore, additional virgin oil must be incorporated into the new asphalt. As the oil content of new asphalt is regulated and required to fall within specific ranges, the oil content of the new asphalt is sometimes examined after it is manufactured to determine its conformity to the specified ranges. The lack of uniformity in the amount of oil recovered from recycled materials may result in inadequate new asphalt that may bring about excessive fines and penalties for asphalt producers. Therefore, a need exists for a system to monitor the oil content provided by recycled materials and to adjust, automatically, the incorporation of virgin oil as necessary, in real time. 
     SUMMARY 
     Systems and methods are provided for monitoring and adjusting the addition of various asphalt components in near real-time. According to one aspect, a system for monitoring and adjusting an asphalt mixture includes at least one processor and a database to store component amount data for a total oil amount and a total aggregate amount for an asphalt mixture. The total oil amount includes a first oil component and a second oil component. The system also includes an asphalt mixture application executable by the at least one processor to receive measurement data of the first oil component added to the asphalt mixture from a sensor. The measurement data identifies a first amount of the first oil component. The application also compares the measurement data to the component parameter data for the asphalt mixture, determines the second amount of a second oil component based upon the measurement data, and transmits an output signal to a metering device in fluid communication with a vessel containing the second oil component, wherein the second amount of the second oil component is added to the asphalt mixture in near real-time. 
     In another aspect, a system for monitoring and adjusting an asphalt mixture includes at least one processor and a database to store component amount data for a total aggregate amount and a total oil amount for an asphalt mixture. The total aggregate amount includes a first aggregate component and a second aggregate component. The system also includes an asphalt mixture application executable by the at least one processor to receive measurement data of the first aggregate component added to the asphalt mixture from a sensor. The measurement data identifies a first amount of the first aggregate component. The application also compares the measurement data to the component parameter data for the asphalt mixture, determines the second amount of a second aggregate component based upon the measurement data, and transmits an output signal to a metering device in fluid communication with a vessel containing the second aggregate component, wherein the second amount of the second aggregate component is added to the asphalt mixture in near real-time. 
     In yet another aspect, a method for monitoring and adjusting an asphalt mixture includes, at at least one processor, receiving measurement data of a first oil component of an asphalt mixture from a sensor. The measurement data identifies a first amount of the first oil component. The method also includes comparing the measurement data to a desired total oil amount, where the desired total oil amount includes the first oil component and a second oil component. Further, the method includes determining a second amount of the second oil component based upon the measurement data and transmitting an output signal to a metering device in communication with a vessel containing the second oil component, wherein the output signal adjusts an output of the second oil component in near real time. 
     In one aspect, a method for monitoring and adjusting an asphalt mixture includes, at at least one processor, receiving measurement data of a recycled oil component of an asphalt mixture from a sensor. The measurement data identifies a first amount of the recycled oil component. The method also includes comparing the measurement data to a desired total oil amount, where the total oil amount includes the recycled oil component and a virgin oil component. If the first amount of the recycled oil component is less than the total oil amount, the method includes determining a second amount of the virgin oil component based upon the measurement data, wherein the total amount of the total oil component equals the sum of the first amount and the second amount, and transmitting a first signal to a metering device in fluid communication with a vessel containing the virgin oil component. The first signal causes the second amount of the virgin oil component to be added to the asphalt mixture in near real time. Alternately, if the first amount of the recycled oil component is equal to the total oil amount, the method includes transmitting a second signal to the metering device in communication with the vessel containing the virgin oil component, the second signal stopping the addition of the virgin oil component. 
     In yet another aspect, a system for monitoring and adjusting an asphalt mixture includes at least one processor and a database to store asphalt mixture amount data for a total oil amount and a total aggregate amount for an asphalt mixture. The total oil amount includes a recycled oil amount and a virgin oil amount and the total aggregate amount includes a recycled aggregate amount and a virgin aggregate amount. 
     The system also includes a asphalt mixture application executable by the at least one processor to: receive first measurement data of the recycled oil amount added to the asphalt mixture from a first sensor, receive second measurement data of the recycled aggregate amount added to the asphalt mixture from a second sensor, compare the first measurement data to the total oil amount, and compare the second measurement data to the total aggregate amount. The asphalt mixture application also determines a virgin oil amount to be added to the asphalt mixture based on the first measurement data and determines a virgin aggregate amount to be added to the asphalt mixture based on the second measurement data. The asphalt mixture application transmits a virgin oil output signal to a first metering device in communication with a first vessel containing virgin oil, where the virgin oil amount is added to the asphalt mixture in near real-time, and transmits a virgin aggregate output signal to a second metering device in communication with a second vessel containing virgin aggregate, where the virgin aggregate amount is added to the asphalt mixture in near real-time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a block diagram of an automated asphalt component mixing system according to one aspect. 
         FIG. 1B  is a block diagram of an automated asphalt component mixing system according to another aspect. 
         FIG. 2  is a plan view layout of an asphalt manufacturing facility incorporating the asphalt component mixing system according to one aspect. 
         FIG. 3  is a plan view layout of an asphalt manufacturing facility incorporating the asphalt component mixing system according to another aspect. 
     
    
    
     DETAILED DESCRIPTION 
     The asphalt component mixing systems and methods generally relate to the preparation and mixing of an asphalt composition. An asphalt composition may be produced from a mixture of a number of components, including but not limited to an aggregate and asphalt oil. Different compositions may include different numbers and ratios of the constituent components. For example, one asphalt composition may be a particular ratio of aggregate to oil (e.g. 60% aggregate to 40% oil), while another asphalt composition may have a ratio of 75% aggregate to 25% oil. Other asphalt compositions may include additional components, such as one or more additives, and may have different ratios for each component. The oil portion may be divided between virgin oil and recycled oil material such that a portion of the total oil is from virgin oil and another portion of the total oil is from recycled oil material. 
     In particular, the system may be used in a constant-flow manufacturing process where the amount of various components within an asphalt mixture that will become an asphalt composition, may be adjusted in real-time. For example, the system may be used to monitor and manipulate the addition of recycled asphalt shingle (RAS) material derived from recycled roofing shingles or other sources to the mixture, as well as providing real-time monitoring and metering of new or virgin asphalt oil (VAO) to the mixture. 
     In one aspect, the amount of VAO added to the mixture is calculated and metered based, at least in part, on the amount of recycled oil derived from the RAS material, or recycled asphalt pavement (RAP) material, and/or another recycled oil material. In addition, the system and process may also provide real-time monitoring and metering of RAS material and/or RAP material derived from previously manufactured asphalt shingles, or pavement to the mixture, as well as monitoring and metering virgin aggregate additions to the mixture. In one aspect, RAP material may be recycled to reclaim oil and aggregate materials. As such, the RAP materials may be included in new asphalt mixtures as only a reclaimed oil source, only a recycled aggregate source, or both. 
     As the actual amount of recycled oil, and in one optional embodiment, recycled aggregate, that may be reclaimed from the RAS material, the RAP material, and/or another recycled oil material is not uniform and may vary at any given moment in the constant-flow process of manufacturing new asphalt, the system and process allows for the automatic addition of precise quantities of VAO to the asphalt mixture. In one aspect, the addition of VAO to an asphalt mixture composition is achieved using programmable logic controllers (PLC) or other computing devices to control the operation of one or more pumps in fluid communication with one or more vessels containing VAO based on sensor data identifying the amount of recycled oil material delivered for the asphalt mixture composition. In various other aspects, the system may be incorporated into new or existing asphalt manufacturing facilities. 
     In one aspect, as shown in  FIG. 1A , the asphalt mixing system  100 A includes a aggregate source  102 , a reclaimed oil (RO) source  104  in communication with an reclaimed oil (RO) sensor  106 , a VAO source  108  in communication with a VAO pump  110 , a mixing drum  112 , various delivery systems  114 A- 114 C, and a computing device  116 . 
     The aggregate source  102  includes aggregate material. Aggregate generally refers to a broad category of coarse particulate material as understood by one having ordinary skill in the art. The aggregate may include sand, gravel, crushed stone, slag, recycled concrete, and/or geosynthetic aggregates, among others. The asphalt mixing system  100  may be used with any suitable aggregate material. Although shown as a single source, the aggregate source  102  may be a single source or distributed sources, such as one or more cold-feed bins, storage bins, storage drums, and/or storage silos. The aggregate source  102  may also include aggregate obtained directly from a primary aggregate source, such as a quarry or an off-site recycling facility. In one embodiment, the aggregate includes recycled aggregate separated from RAP or other recycled material 
     The RO source  104  includes asphalt oil and/or asphalt oil material recovered from RAP, the RAS material, and/or another recycled or reclaimed oil material. The RO material is some portion (including from zero to 100%) of the total asphalt oil delivered to the mixing drum  112 . An amount of RO and an amount of VAO make up a total amount of asphalt oil delivered to the mixing drum. For example, asphalt oil may be extracted from the RAP and separated from the recycled aggregate. Similarly, asphalt oil may be derived or extracted from ground asphalt shingles. Although shown as a single source, the RO source  104  material may be a single source or distributed sources, such as one or more cold-feed bins, storage bins, storage drums, and/or storage silos. The RO source  104  may also refer to any of the various tools and machinery used for recycling pavement, shingles, and/or another asphalt oil material. 
     The RO source  104  is in communication with the RO sensor  106  that measures the amount of RO that is being delivered to the asphalt mixture. The RO sensor  106  may be, for example, a weight-determining sensor, such as a load cell, a weigh depletion sensor, a volume-determining sensor, or another sensor to determine the amount of reclaimed oil material delivered to the mixing drum  112 . In one aspect, the RO sensor  106  measures the weight of the reclaimed oil material from the RO source delivered to the mixing drum  112 . In another aspect, the RO sensor  106  measures the volume of liquid reclaimed oil material delivered to the mixing drum  112 . In another aspect, the RO sensor  106  determines the volume, weight, or other parameter of the reclaimed oil material blown, pumped, or otherwise delivered to the mixing drum  112 . 
     In one aspect, the delivery systems  114 A and  114 B include at least one sensor or device to weigh the material transported by the delivery systems. For example, one or more transducers, such as load cells, may be incorporated into or at least in communication with the delivery systems  114 A and  114 B. As such, the load cells, can measure the weight of the materials transported by the delivery systems  114 A and  114 B. One or more load cells may be placed along the entire length of the delivery systems  114 A- 114 B, or alternately, the one or more load cells may be positioned at particular locations along the delivery systems. 
     In other aspects, the RO may not be completely separate from recycled aggregate material. For example, asphalt oil may not be completely separated from aggregate or other material, including dust, derived from recycled shingles. As the oil content of the roofing shingles may be known or determined prior to recycling, the RO sensor  106  may determine the weight of the oil-containing RAS material that is being delivered to the mixing drum  112 . In various other aspects, the RO sensor may capture other parameters of the RO material. As such, the RO sensor  106  captures data relevant to determining the amount of RO provided to the mixing drum  112 . 
     The VAO source  108  is a source of virgin asphalt oil used in the manufacture of new asphalt. The VAO is some portion (including from zero to 100%) of the total asphalt oil delivered to the mixing drum  112 . An amount of VAO and an amount of RO make up a total amount of asphalt oil delivered to the mixing drum. In one example, the VAO is used to supplement and/or augment the volume of RO material delivered to mixing drum  112 . 
     The VAO pump  110  controls the amount of VAO delivered to the mixing drum  112  from the VAO source  108 . The VAO pump  110  can increase or decrease the amount of VAO delivered to the mixing drum  112  in real-time. For example, an asphalt mixture having an oil content of approximately 20% may be composed of 80% aggregate, 10% RO, and 10% virgin oil. The virgin oil may used or the amount of virgin oil may be increased, if the oil content of the recycled oil material is non-uniform, unknown, insufficient, or if is determined the actual amount of RO being delivered to the mixing drum  112  is less than the calculated amount of RO that was initially to be delivered to the mixing drum. The actual ratio of RO to VAO can be varied in real time by the asphalt mixing system  100 A. 
     The various input components used in an asphalt mixture are delivered to the mixing drum  112  by delivery systems  114 A-C. The delivery systems  114 A-C may be any mechanism suitable for transporting the materials from the respective sources  102 ,  104 , and  108  to the mixing drum  112 , such as one or more of an auger conveyor, a pneumatic conveyor system, a conveyor belt, a pump, one or more pipes, or one or more other delivery mechanisms. For example, the delivery systems  114 A and  114 B may include one or more conveyor belts and/or one or more auger conveyors. Similarly, the delivery system  114 C may be any delivery system suitable for transporting the VAO, including but not limited to various lengths of piping. For example, the delivery system for the VAO may be configured for transferring liquids. Other delivery systems for transporting materials and systems for holding and/or storing materials may be used, including but not limited to hoppers. 
     In one embodiment, the operation of the VAO pump  110 , and therefore the amount of VAO provided to the asphalt mixture, is controlled by the computing device  116  or another control system. In operation, the computing device  116  receives data from various components, such as the RO sensor  106 , to continuously monitor the amounts of materials delivered to and/or added to the mixing drum  112 . In response to changes in the amount of materials delivered to and/or added to the mixing drum  112 , the computing device  116  recalculates the amount of the other materials, in real-time, to be delivered to and/or added to the mixing drum to achieve a particular product mixture. 
     For example, the computing device  116 , may receive input from the RO sensor  106  to determine the actual amount of RAS material or other RO material being delivered to and/or added to the mixing drum  112 . As the computing device  116  determines the amount of the RAS material that is delivered to the mixing drum  112 , it simultaneously adjusts the pump  110  to modify and meter the flow of VAO delivered from the VAO source  108  to the mixing drum  112 . The computing device  116  therefore, causes the amount of VAO pumped in to the mixing drum  112  to increase or decrease depending on the actual, measured amount of RAS material or other RO material that is delivered to and added to the mixing drum  112 . 
     Thus, the computing device  116  retrieves data identifying the desired amount of the components (aggregate, RO material, and/or VAO) to be delivered to the mixing drum  112  for a particular asphalt mixture from a database or other data storage location, including the memory  120 , and receives data from one or more sensors, including the RO sensor  106 , indicating the actual amount of the components (aggregate, RO material, and/or VAO) delivered to the mixing drum. The desired amounts of RO material, VAO, and aggregate may be, for example, pre-determined or pre-defined amounts for an asphalt mixture or amounts stored in a database or calculated by the computing device  116  for an asphalt mixture. The computing device  116  also determines modifications to one or more delivery systems  114 A-C to meter (adjust) the amount of material from one or more sources, including at least the VAO pump  110  to pump VAO from the VAO source  108 , and transmits one or more signals to the one or more delivery systems or sources  102 ,  104 ,  108 , including the VAO pump, to meter the amount of material, including at least VAO, delivered to the mixing drum  112 . In response to receiving one or more signals from the computing device  116 , the receiving delivery system  114 A-C or source  102 ,  104 , and  108 , including at least the VAO pump  110 , meters (adjusts) the amount of material delivered by the delivery system to the mixing drum  112 . 
     By way of example and not limitation, the computing device  116  may retrieve data for a particular asphalt composition that requires 60% aggregate by weight and 40% oil by weight. The computing device  116  also may retrieve or calculate the optimal delivery or flow rate for the aggregate and oil to achieve the desired composition. During the manufacturing process, the computing device  116  receives data from the RO sensor  106  indicating that the delivery or flow of RO material and therefore RO is insufficient to produce an asphalt composition that is 40% weight by volume. For example, the delivery of the RO material may be decreased or stopped. In response, the computing device  116  generates and transmits a signal to the VAO pump  110  to initiate or increase the delivery of VAO to the mixing drum  112  to compensate for the insufficiently delivered RO material. The VAO pump  110  receives the signal and initiates or increases the output of VAO from the VAO source  108  to be delivered to the mixing drum  112 . 
     In another example, the computing device  116  may receive data from the RO sensor  106  indicating that the flow of RO material is increasing or is otherwise sufficient to deliver the necessary amount of RO to the mixing drum. In response, the computing device  116  generates and transmits a signal to the VAO pump  110  to decrease or halt the delivery of VAO to the mixing drum  112 . The VAO pump  110  receives the signal and decreases or halts output of VAO from the VAO source  108  to be delivered to the mixing drum. 
     In other examples, the computing device  116  may receive data from the aggregate sensor  126  regarding the delivery or flow of recycled aggregate material from an aggregate source  102  to the mixing drum  112  and generate signals that are received at the aggregate source or delivery system  114 A to increase or decrease the amount of virgin aggregate provided to the mixing drum. In response, the aggregate source  102  or delivery system  114 A increases or decreases the amount of aggregate delivered to the mixing drum  112 . The computing device  116  may receive data from one or more sensors and adjust the flow of one or more components in real-time, during the manufacturing process. 
     In one aspect, the computing device  116  includes at least one processor  118  and memory  120 . For example, the computing device  116  may be a programmable logic controller (PLC), a personal computer, workstation, server, or mobile device. The processor  118  is a hardware device that processes software, other machine-readable instructions, retrieved data, and/or received data. The memory  120  may store the software or other machine-readable instructions and data. The memory  120  may include volatile and/or non-volatile memory. The memory  120  may comprise a database to store data identifying the desired amounts of RO material, VAO, and aggregate for an asphalt mixture, such as in pre-determined or pre-defined amounts, and a total amount of oil comprised of one or more of virgin oil and recycled oil material. The computing device  116  may further include various hardware and accompanying software components that may be configured for receiving data from one or more of the asphalt component sources  102 ,  104 ,  108 , and/or one or more sensors, such as the RO sensor  106 . 
     Additionally, the computing device  116  may also include a communication system to communicate with one or more components of the asphalt mixing system  100 A, such as the RO sensor  106  and optionally other sensors, sources, and/or delivery systems, over a communication network via wireline and/or wireless communications, such as through the Internet, an intranet, and Ethernet network, a wireline network, a wireless network, and/or another communication network of the asphalt mixing system. The computing device  116  may further include a display (not shown) for viewing data or one or more user interfaces (UI), such as a computer monitor, and an input device (not shown), such as a keyboard or a pointing device (e.g., a mouse, trackball, pen, touch pad, or other device) for entering data and navigating through data, including images, documents, structured data, unstructured data, HTML pages, other web pages, and other data. 
     The computing device  116  may include a database (not shown) and/or is configured to access the database. The database may be a general repository of data including, but not limited to, user data, asphalt composition mixture data, or any other data related to asphalt production, including data regarding the type and amount of components (aggregate, RO material, and/or VAO) in various asphalt compositions, operating parameters of the various components at an asphalt manufacturing plant, such as processing capacities and rates and delivery system capacities and rates. For example, the database stores data identifying the desired amounts of RO material, VAO, and aggregate for an asphalt mixture, such as in pre-determined or pre-defined amounts. The database may include memory and one or more processors or processing systems to receive, process, query and transmit communications and store and retrieve such data. In another aspect, the database may be a database server. 
     According to one aspect, the computing device  116  includes a computer readable medium (“CRM”)  122 , which may include computer storage media, communication media, and/or another available media medium that can be accessed by the processor  118 . For example, CRM  122  may include non-transient computer storage media and communication media. By way of example and not limitation, computer storage media includes memory, volatile media, nonvolatile media, removable media, and/or non-removable media implemented in a method or technology for storage of information, such as machine/computer readable/executable instructions, data structures, program modules, or other data. Communication media includes machine/computer readable/executable instructions, data structures, program modules, or other data and includes an information delivery media or system. The CRM  122  may store executable instructions to implement an asphalt constituent mixture application  124  to implement the sensor monitoring and VAO pump operation to meter the VAO. For example, the asphalt constituent mixture application  124  is loaded or stored on the CRM in one example. Generally, program modules include routines, programs, instructions, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. 
     The asphalt mixture application  124  receives sensor data from one or more of the sensors, including the RO sensor  106 . The sensor data identifies measured amounts of material. The asphalt mixture application  124  compares the sensor data to pre-defined or calculated data identifying desired amounts of material, determines adjustment amounts (increases, decreases, initiations, or halts) for the VOA to be added to the asphalt mixture, and controls sending one or more signals to the VOA pump  110  to adjust the output of the amount of VOA delivered from the VOA source  108  to the mixing drum  112 . For example, one or more of the desired amounts are stored as parameters identifying pre-defined or pre-determined amounts of RO material and/or VOA and/or aggregate to be delivered to the mixing drum  112  for the asphalt mixture. 
     In one example, the asphalt mixture application  124  retrieves the pre-defined component amount data from the database. The pre-defined component amount data identifies pre-defined or pre-determined amounts of RO material and/or VOA and/or aggregate to be delivered to the mixing drum  112  for the asphalt mixture. The asphalt mixture application  124  receives the measured amount of RO material from the RO sensor and compares the measured amount of RO material to the pre-defined amount of RO material. The asphalt mixture application  124  determines an amount of the VOA needed for the asphalt mixture based upon the comparison of the measured amount of RO material to the pre-defined amount of RO material, such as more, less, none, or at least some. The asphalt mixture application  124  transmits a signal to the VO pump  110  to adjust (initiate, increase, halt, or decrease) a pumped amount of the VOA pumped from the VAO source  108  to be the determined amount. 
     In another example, the asphalt mixture application  124  receives measurement data of a first oil component added to the asphalt mixture from a sensor. The measurement data identifies a first amount of the first oil component. The application also compares the measurement data to the component parameter data for the asphalt mixture, determines the second amount of a second oil component based upon the measurement data, and transmits an output signal to a metering device in fluid communication with a vessel containing the second oil component, wherein the second amount of the second oil component is added to the asphalt mixture in near real-time. 
     In one aspect, the computing device  116  with a database, a processor  118 , and an asphalt mixture application  124  collectively are referred to as a control system. 
     The VAO pump  110  has circuitry, hardware, and/or software to receive one or more signals from the computing device  116  and increase, decrease, initiate, or halt the delivery or flow of VAO from the VAO source  108  in response to the one or more signals. Optionally, the aggregate source  102 , RO source  104 , delivery system  114 A, and/or delivery system  114 B optionally each have circuitry, hardware, and/or software to receive one or more signals from the computing device  116  and increase, decrease, initiate, or halt the delivery or flow of material from respective sources to the mixing drum in response to the one or more signals. 
       FIG. 1B  depicts another embodiment of the asphalt mixing system, indicated as  100 B. In this embodiment, the computing device also receives data regarding the amount of aggregate and VAO actually delivered to the mixing drum  112 , from an aggregate sensor  126  and a virgin asphalt oil (VAO) sensor  128 . For example, the aggregate sensor  126  may be one or more load cells, weigh depletion sensors, other weight determining sensors, or another type of sensor. The VAO pump  110  may be used to meter the VAO transported by the delivery system  114 C, and the VAO sensor  128  may be incorporated along the delivery system  114 C to provide additional data regarding the VAO pumped to the mixing drum  112 . The VAO sensor  106  may be any suitable sensor or meter, including but not limited to a flow meter, to precisely measure the volume of VAO delivered to the mixing drum  112 . 
     By also monitoring the aggregate and VAO delivered to the mixing drum  112 , a user of the asphalt mixing system  100  may ensure that the desired ratios of aggregate-to-oil delivered to the mixing drum  112  are maintained. The user may also be able to identify any deficiencies in the materials provided to the mixing drum  112 , which may indicate a blockage or broken machinery in the asphalt plant. 
     In addition, by monitoring all of the materials intended to enter the mixing drum  112 , the user may further change the composition of the asphalt mixture, in real time, to increase or decrease the aggregate-to-oil ratio of the mixture delivered to the mixing drum  112 . 
     Referring now to  FIG. 2 , a plan view layout of an asphalt manufacturing facility  200  incorporating the asphalt mixing system  100  is shown. An aggregate source  102  is in communication with a delivery system  202 , such as a conveyor belt, that transports aggregate material to a dryer  204 , such as a drying drum. Similarly, aggregate obtained from a RAP source  206 , optionally is transported by another delivery system  208 , such as a conveyor belt or auger conveyor, to the dryer  204 . In one aspect, the virgin aggregate and recycled aggregate derived from RAP may be transported by the same delivery system. The aggregate source  102  and the RAP source  206  each may include one or more cold feed bins or other storage or holding structures containing the respective aggregate material. The cold feed bins are configured to drop quantities of the aggregate and the RAP material onto the respective delivery systems  202  and  208 . In one aspect, each delivery system  202  and  208  includes at least one load cell, weigh depletion sensor, or other sensors  210  and  212 , respectively to measure the amount of aggregate and RAP material provided to the dryer  204 . The RAP source  206 , the delivery system  208 , and the sensor  212  are optional in some embodiments. 
     The dryer  204  heats the aggregate material to remove moisture and improve subsequent bonding between the aggregate and the asphalt oil in the mixing drum  112 . The dryer  204  may be any dryer or drying drum suitable for heating and drying the aggregate material. 
     While drying, heated air blown into the dryer  204  extracts large amounts of dust and sand from the heated aggregate mix and carries it to a receiver/blower  214 , such as a baghouse, where the air is filtered and the fine particles are collected. These particles are fed back into the mixing drum  112 , as generally indicated by  216 , to become part of the new asphalt mix. Any suitable configuration for the receiver/blower  214  may be used. The aggregate material remaining in dryer  204  is transferred to the mixing drum  112  via another delivery system  218 . 
     One source of asphalt oil for the asphalt mixture is oil reclaimed from RAS material. In one aspect, roofing shingles are shredded or ground in a shredder or grinder  220 . The RAS material is passed through the shredder or grinder  220  in one or more passes. In one example, during a first pass, the RAS material is reduced to pieces approximately ¼″ by ¼″. In a second pass, the RAS material is further reduced to approximately ⅛″ by ⅛″. Though in other instances, the RAS material may be ground or shredded in a single pass. In one example, the ground or shredded RAS material is less than approximately ⅛″. In another example, the ground or shredded RAS material is between approximately 1/16″ to ½″. 
     Similar to the aggregate material, the shredded or ground RAS material is carried to a receiver/blower  222 , such as a baghouse, where the dust is filtered and collected. In one aspect, the entirety of the RAS material is filtered though the receiver/blower  222 , before being carried to the mixing drum  112 . In another aspect, a cyclone separator  224  is used is used to remove larger pieces of the RAS material by cyclonic separation, before the fine dust particles are carried to the receiver/blower  222 . The larger pieces are carried by a delivery system  226  to the mixing drum  112 . The delivery system  226  may be configured as a conveyor belt, a hopper-belt conveyor, an auger conveyor, or a pneumatic conveyor, among others. 
     Due to the small particle size of the pulverized (e.g. ground or shredded) RAS material, there is a potential for the RAS material to clump, thereby by causing intermittent or partial blockages of the delivery system  226 . For example, the RAS material may clog an auger-based delivery system. Therefore, despite weighing the RAS material after grinding or shredding, the amount of RAS material actually delivered to or being fed into the mixing drum  112  may not be a constant value and may vary from the calculated or pre-determined or pre-defined value. As such, the amount of RO delivered to the mixing drum  112  may vary. 
     To account for variance in the amount of RAS material delivered to the mixing drum  112 , the amount of RAS material is measured by one or more sensors, such as the RO sensor  106 . In one embodiment, the RO sensor  106  is a weigh depletion sensor or load cell that determines the weight of the RO material delivered to the mixing drum  112  For example, a weigh depletion sensor, such as one or more load cells, measures or determines weights of a storage or holding bin or device in which material is stored or held and determines the amount of material dispersed from the bin or device by measuring or determining the change in weight or mass of the bin or device. In this embodiment, the weight and oil content of the RAS material is known or at least determined prior to processing the shingles. Subsequent measurements of the weight of the RAS material may be used to determine the actual amount of RAS material delivered to the mixing drum, and therefore determine the amount of RO delivered to the mixing drum  112 . While it is believed that weight depletion is one method of determining the amount of RAS delivered to the mixing drum, other methods may be used, including but not limited to, monitoring the depletion level within a pulverized RAS cold-feed storage bin, weighing material on or passing over or through the delivery system, etc. 
     In one aspect, the data from the RO sensor  106  is transmitted to the computing device  116 , located in a control area  228 , such as a building. Although shown in a detached control area  228 , the computing device  116  may be located in any suitable location. The computing device may be configured to receive and transmit data by a wired connection or by a wireless connection to the one or more sensors, such as the RO sensor  106 . 
     In one embodiment, the computing device  116  is a programmable logic controller (PLC)  230  that has been specially programmed to adjust the output of the VAO pump  110 , in real-time, in response to the data received from the RO sensor  106 . For example, when the PLC  230  determines the weight and therefore amount of the RAS material delivered to and entering the mixing drum  112  decreases or is otherwise insufficient to provide the desired amount of RO, the PLC automatically and simultaneously adjusts the output of the VAO pump  110  to increase the flow of VAO from the VAO storage tank(s)  232  or other VAO source through the delivery system  234  and into the mixing drum  112 . Conversely, when the PLC  230  determines that the weight and therefore amount of the RAS material delivered to and entering the mixing drum  112  is increasing or is otherwise sufficient to provide the desired amount of RO, the PLC automatically and simultaneously adjusts the output of the VAO pump  110  to decrease, maintain, or stop the flow, as needed, of VAO from the VAO storage tank(s)  232  or other VAO source into the mixing drum  112 . Therefore, to maintain the desired oil content in the mixing drum  112 , the amount of VAO is automatically varied, in real-time, to account for variance in the amount of RO delivered to and entering the asphalt mixture in the mixing drum  112 . The desired amounts of RO, VAO, and aggregate may be, for example, pre-determined or pre-defined amounts for an asphalt mixture or amounts calculated by the PLC  230  for an asphalt mixture. 
     Thus, the PLC  230  retrieves data identifying the desired amounts of the components (aggregate, RO material, and/or VAO), such as from a database, to be delivered to the mixing drum  112  for a particular asphalt mixture from a database or other data storage location, including memory of to the PLC and receives data from one or more sensors, including the RO sensor  106 , indicating the actual amounts of the components (aggregate, RO material, and/or VAO) delivered to the mixing drum. The PLC  230  also determines modifications to one or more delivery systems  202 ,  208 ,  218 ,  226 , and  234  to meter (adjust) the amount of material from one or more sources, including at least the VAO pump  110  to pump VAO from the VAO source  232 , and transmits one or more signals to the one or more delivery systems or sources  102 ,  104 ,  108 , including at least the VAO pump  110  to meter the amount of VAO material delivered to the mixing drum  112 . In response to receiving the signal from the PLC  230 , the receiving delivery system  202 ,  208 ,  218 ,  226 ,  234  or source  102 ,  206 ,  220 , and  232 , including at least the VAO pump  110 , meters (adjusts) the amount of material delivered by the delivery system to the mixing drum  112 . 
     By way of example and not limitation, the PLC  230  may retrieve pre-defined or pre-determined or pre-defined data identifying amounts for a specific asphalt composition (mixture) that requires 75% aggregate by weight and 25% oil by weight. The PLC  230  also may retrieve or calculate the optimal flow or delivery rate for the aggregate and oil to achieve the desired composition. During the manufacturing process, the PLC  230  receives data from the RO sensor  106  indicating that the flow of RO material and therefore the amount of RO is decreasing or is insufficient to produce an asphalt composition that is 25% weight by volume. In response, the PLC  230  generates and transmits a signal to the VAO pump  110  to initiate or increase the delivery of VAO to the mixing drum  112 . For example, the signal may indicate the VAO pump  110  must increase output by 50%. The VAO pump  110  receives the signal and initiates or increases the output of VAO accordingly. 
     In another example, the PLC  230  may receive data from the RO sensor  106  indicating that the flow of RO material is increasing or is otherwise sufficient to deliver the necessary amount of RO to the mixing drum. In response, the PLC  230  generates and transmits a signal to the VAO pump  110  to decrease or halt the delivery of VAO to the mixing drum  112 . For example, the signal may indicate the VAO pump  110  must decrease the output of VAO by 50%. The VAO pump  110  receives the signal and decreases the output of VAO accordingly. 
     In other examples, the PLC  230  may receive data from the sensor  212  regarding the flow of recycled aggregate material from the RAP source  206  to the mixing drum  112  and generate signals that are received at the aggregate source  102  or delivery system  202  to increase or decrease the amount of virgin aggregate provided to the mixing drum. The aggregate source  102  or delivery system  202  receives the signal and adjusts the amount of aggregate delivered to the mixing drum  112  accordingly. The PLC  230  may receive data from one or more sensors and adjust the flow of one or more components in real-time, during the manufacturing process. 
     In other embodiments, the PLC  230  may receive data from additional sensors such as the aggregate sensor  126 , the VAO sensor  128 , and a RAP sensor  212 . For example, the aggregate sensor  126  or the RAP sensor  212  may be load cells or weigh depletion sensors to weigh the respective aggregate materials delivered to the asphalt mixture or other sensor types to determine an amount of material delivered to the asphalt mixture. Moreover, although RAP may be used as an aggregate constituent to reduce the amount of virgin aggregate in the asphalt mixture, RAP may contain a significant amount of RO, which may impact the oil content of the asphalt mixture. Therefore, in one aspect, the computing device  116  may rely upon input from the RAP sensor  212  to adjust the input of virgin aggregate and/or VAO due to the aggregate and/or RO contributions, respectively, of the RAP. 
     By way of example and not limitation, the weight of the RAP may be determined as it passes the RAP sensor  212  before it is ultimately delivered to the mixing drum  112 . The RAP sensor  212  measures the weight of the RAP delivered by the delivery system  208  and transmits the data to PLC  230 , where the amount of virgin aggregate from the aggregate source  102  is adjusted accordingly. In one example, RAP is fed into the dryer  204  by the delivery system  208 . In another example, RAP is delivered directly to the mixing drum  112  by the delivery system  208  and is not fed into the dryer  204 . 
     In an embodiment, the PLC  230  therefore monitors and adjusts, in real-time, the combined aggregate input consisting of virgin aggregate and optionally recycled aggregate from the RAP, as well as the combined asphalt oil input consisting of oil contained in the RAS material and the VAO to produce a new asphalt mixture composition. As a result, the new asphalt mixture composition has maximized quantities of recycled material from the RAS and optionally RAP, while minimizing the amount of higher-cost virgin materials, such as the VAO and virgin aggregate. Moreover, the PLC  230  may be reprogrammed quickly and efficiently to modify the aggregate-to-oil ratio of the asphalt mixture, in response to legislative, industry, or specific application demands. For example, in one embodiment where the RAP material is reclaimed only as an aggregate source, the amount of VAO delivered to the mixing drum  112  is based on the availability of RO from the RAS. Conversely, in an embodiment where oil is reclaimed from the RAP material, the amount of VAO delivered to the mixing drum  112  is based on the total amount of recycled oil reclaimed from the RAS and RAP materials. 
     After the desired quantities of aggregate and oil have been delivered to the mixing drum  112 , new asphalt is produced and transferred to one or more storage silos  236 A-C by the delivery system  238  for storage. The asphalt mixing system  100  may be configured to vary the aggregate-to-oil ratio of the new asphalt during production, such that multiple and varied compositions of asphalt may be produced in rapid succession and stored in the one or more storage silos  236 A-C. 
       FIG. 3  depicts another asphalt manufacturing facility  300  incorporating the asphalt mixing system  100 . In this embodiment, the pulverized (e.g. ground or shredded) RAS material is transported predominately by a pneumatic system, indicated generally as  302 . The pneumatic system  302  is configured to maximize the RAS material provided to the mixing drum  112  and minimize the potential for clogging. Regardless of the manner in which the RAS material is transported, the amount of RAS material delivered to the mixing drum  112  is monitored in real-time. 
     It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. 
     While the present disclosure has been described with reference to various embodiments, it will be understood that these embodiments are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, embodiments in accordance with the present disclosure have been described in the context of particular implementations. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow. 
     Those skilled in the art will appreciate that variations from the specific embodiments disclosed above are contemplated by the invention. The following invention should not be restricted to the above embodiments, but should be measured by the following claims.