Transforming the Intelligent Compaction Analyzer

Abstract

Methods, apparatus, and systems for providing an estimate of the compaction level of a pavement material layer in real time. In some embodiments, a Reconstructed Intelligent Compaction Analyzer (RICA) processor of the RICA device receives vibration energy data from a sensor module corresponding to an impact response of a roller of a roller during compaction of pavement material on a section of pavement. The RICA processor also receives temperature data from the sensor module, determines an estimated compaction level of the section of pavement in real time based on the vibration energy data, pavement material property data, and temperature data, and displays a density level percentage of the section of pavement on a display device for viewing by an operator of the roller.

Description

Technical Field

[0001] A method and apparatus for providing an estimate of the level of compaction during compaction of pavement materials. Specifically, a retrofit smart compaction analyzer apparatus that can be retrofitted to a vibrating compactor to provide an operator with an estimate of the level of compaction of pavement materials in real time. The compaction level estimate can provide density information in a format suitable for an operator of the compactor to understand and use to determine when adequate compaction has been achieved for a particular portion of a road during its construction. Background Art

[0002] Asphalt pavement is designed to carry traffic loads with minimal physical degradation, maximum safety and maximum driving comfort. Based on the design, asphalt pavement is expected to withstand traffic loads of up to 30 million equivalent single axle loads (ESAL) over a 20-year service life.

[0003] The finished asphalt pavement is the result of a multi-stage process: from pavement design according to specifications, to construction and quality assurance. The process starts with designing the pavement according to specifications based on the type of road, traffic volume, intended use, subgrade conditions, and seasonal changes that the road must withstand. The next steps include producing the hot mix asphalt according to the design, transporting the asphalt mix from the production facility to the construction site, placing the mix, and then compacting the mix using a vibratory roller to achieve the desired density.

[0004] Compaction is one of the most important steps in pavement construction because it significantly affects the quality of the constructed pavement. Compaction increases the interlocking between aggregates, thereby reducing the air void content between aggregates. Studies have shown that in order to achieve optimal performance of asphalt pavements, the air void content needs to be between three percent (3%) and five percent (5%). Inadequately compacted pavements will deteriorate prematurely due to increased fatigue. Experiments have shown that reducing the air void content of a given asphalt concrete mix from eight percent (8%) to five percent (5%) can increase the fatigue life of the pavement by one hundred percent (100%). Proper compaction can also reduce the permeability of the mix, increase load-bearing capacity, increase resistance to deformation (or rutting), and increase the durability of the pavement. Proper compaction can also reduce pavement degradation due to rutting, oxidation, moisture damage, deformation, and disintegration or fall apart of the pavement. Therefore, proper compaction of asphalt pavements is required to achieve their design properties and ensure their characteristics and service life.

[0005] In the process of paving asphalt for roads, a variety of graded aggregates may be used. The aggregates are typically mixed with asphalt cement (tar) and sand and then heated to between approximately 150 degrees Celsius (C°) and 169 degrees Celsius. A paver lays the hot asphalt mixture and then levels it using a series of augers and scrapers. When initially laid to form a road, the asphalt material is not dense enough to adequately support vehicle traffic due to voids that form in the asphalt mixture. Therefore, a roller is typically used to make multiple passes over a layer of asphalt material ("asphalt mat"), wherein an operator drives the roller back and forth over the asphalt material, or otherwise creates sufficient compaction to form asphalt (or to form a separate pavement layer) with the desired strength for a pavement.

[0006] A road roller achieves compaction by applying compaction energy to a material (e.g., soil, asphalt, etc.) as the vibratory compactor passes back and forth over the material. The compaction energy is typically applied by an eccentric weight that rotates within the drum of the vibratory compactor, or by a vibrating screed that also levels the road surface. In the United States, in order to meet state Department of Transportation (State DoT) material compaction requirements, it is typically necessary to compact the asphalt mat to a desired hardness level without overcompacting the mix. Furthermore, it is well known that overcompacting can cause irreversible damage to the pavement or roadway.

[0007] Currently, there is no accepted quality assurance method by State DoTs for evaluating the hardness of completed pavement. To assess the quality level of an asphalt mat, in many cases one or more pavement cores are extracted from a completed pavement project after the asphalt has cooled, and the cores are then tested to determine their bulk properties and density. The basic premise is that the density of the core is related to the hardness, and all other variables being constant, the hardness is directly affected by the density. Early deterioration of the pavement due to rutting, fatigue cracking, and other types of damage can be due to insufficient hardness achieved during the compaction process. Therefore, State DoTs typically specify a target density of approximately 94% to 96% of the theoretical maximum density of the asphalt mix (%TMD) as the metric for acceptance testing. In the case of a soil roadbed, acceptance tests are typically specified based on density and moisture content.

[0008] Conducting core measurements is expensive, time consuming, and may not be indicative of the overall compaction achieved unless such core measurements are conducted at a large number of points distributed in a grid fashion, which is difficult to achieve in the field and may be prohibitively expensive. In addition, different states and / or different counties and / or jurisdictions or municipalities in the United States may each have different compaction density requirements. Furthermore, since pavement density acceptance testing is typically conducted after road construction is complete, there is no opportunity to achieve additional compaction if necessary. Most state DOTs cannot accept failure to achieve target density requirements, so remedial measures are taken when necessary, which can result in significant cost overruns.

[0009] Vibratory compactor or roller manufacturers have recently introduced several intelligent compaction (IC) technologies that attempt to achieve uniform compaction of the soil and aggregate base by varying compactor parameters (e.g., vibration amplitude and frequency, thrust vectoring, etc.) during the compaction process. Dynamic control of roller parameters allows vibration energy to be applied only to undercompacted areas to prevent overcompaction in other areas, thereby achieving uniform compaction of the pavement layer. While these intelligent compaction (IC) technologies may have some future promise, their overall performance has not yet been fully evaluated in the field. In addition, many of these IC products require construction companies to purchase new vibratory compactors equipped with the technology, which is an expensive proposition.

[0010] Therefore, there is a need for tools and / or techniques that can be retrofitted to existing vibratory compactors or rollers that enable operators to estimate compaction levels in real time during road construction to determine if any corrective steps should be taken to achieve a desired level of compaction quality in the road construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features and advantages of some embodiments of the present disclosure, and the manner in which they are achieved, will become more apparent upon consideration of the following detailed description in conjunction with the accompanying drawings, which illustrate preferred and exemplary embodiments and are not necessarily drawn to scale, wherein:

[0012] Figure 1 is a block diagram of a vibratory compactor according to an embodiment of the present disclosure;

[0013] Figure 2 is a block diagram of different modules of an embodiment of a Retrofit Intelligent Compaction Analyzer (RICA) according to the present disclosure;

[0014] Figure 3A FIG. 1 is a diagram showing the compaction of an asphalt road surface during each pass over a portion of the road surface, such as during each pass over a portion of the road surface, according to some embodiments of the present disclosure. Figure 2 A diagram of the vibration of the drum of a road roller shown in;

[0015] Figure 3B is a diagram showing the compaction process according to some embodiments of the present disclosure Figure 3A A vibration spectrum diagram showing the frequency components (in Hertz) of the vibration shown in FIG.

[0016] Figures 4A-4F is a graph showing vibration of the drum at different frequencies during the compaction process;

[0017] Figure 5 4 is a graph showing the normalized power of each frequency band shown in FIG. 4 .

[0018] Figure 6is a graph showing vibrations of a roller during compaction of a pavement layer classified into clusters representing different compaction levels according to an embodiment of the present disclosure;

[0019] Fig. 7A , 7B and 7C are graphs showing estimated density according to an embodiment of the present disclosure;

[0020] Figure 8 A display screen showing a Retrofit Intelligent Compaction Analyzer (RICA) device that may be provided to an operator of a vibratory compactor or roller according to an embodiment of the present disclosure; and

[0021] Fig. 9 is a flow chart illustrating a method for providing an estimate of the compaction level of pavement material to an operator of a road roller in real time according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] Reference will now be made in detail to various novel embodiments, examples of which are shown in the accompanying drawings. The drawings and their description are not intended to limit the invention to any particular embodiment. On the contrary, the description provided herein is intended to cover its replacement, modification and equivalents. In the following description, many specific details are set forth in order to provide a thorough understanding of the various embodiments, but some or all embodiments may be practiced without some or all of the specific details. In other cases, well-known process operations are not described in detail to avoid unnecessarily obscuring novel aspects.

[0023] In general, and for the purpose of introducing the concepts of embodiments of the present disclosure, disclosed herein are methods and apparatus for providing an estimate of the compaction (or density) level of pavement material to an operator of a roller in real time during the compaction process. In one embodiment, a Retrofit Intelligent Compaction Analyzer (RICA) device is retrofitted to a roller or vibratory roller. The RICA device utilizes data from various sensors to generate a compaction level estimate in real time to an operator of a roller of pavement material being used to construct a road. In some embodiments, the compaction level estimate provides density and / or hardness information in a format suitable for the operator of the roller to understand and determine when sufficient compaction has been achieved for a particular portion of the road. It should be understood that although the present disclosure includes examples regarding compacting asphalt materials and / or pavement during road construction, the disclosed methods, apparatus, and systems can be used to estimate hardness information for any material layer, for example, soil that is being compacted.

[0024] The compactability of an asphalt mix depends on several factors related to the environment, mix properties, and construction process. These factors include the temperature of the asphalt mix when laid, the thickness of the layer, the temperature and compactness of the underlying layer, ambient temperature, air velocity and humidity, and solar radiation levels. For example, the minimum layer thickness must be three to four times the nominal maximum aggregate size to allow the aggregates to rearrange and interlock during compaction. The mix must also be above a certain temperature, called the abort temperature, to make it pliable. Unless these factors are addressed during construction, they can result in undercompacted and / or uneven compaction of the pavement.

[0025] Therefore, in order to obtain a high-quality and long-lasting asphalt pavement, a well-designed and controlled compaction process is essential. On the one hand, insufficient compaction can leave a high percentage of air pockets within the pavement, making it susceptible to moisture infiltration, oxidation and cracking. On the other hand, excessive compaction can result in very low air pockets, which can lead to asphalt seeping into the pavement during hot weather conditions. Excessive compaction can also cause aggregate fragmentation, thereby changing the mechanical properties of the pavement. As a result, poorly compacted pavements do not meet design specifications and are prone to premature degradation and deterioration. Non-durable paved roads are very costly to repair and maintain and can lead to traffic congestion, which in turn increases emissions from cars, buses and trucks that pollute the environment.

[0026] As mentioned above, conventional road compaction involves vibratory rollers that move at a constant speed and apply vibratory forces of constant amplitude and frequency. Vibratory rollers or compactors apply static and dynamic forces (weight and vibration) to increase interlocking between aggregates, thereby reducing air pockets in the compacted mix. In addition to mix and environmental conditions, the level of compaction achieved depends on the type of roller, the number of rollers, and the rolling pattern used during compaction.

[0027] One of the goals of mechanical design of asphalt pavements is to address the long-term performance of the pavement. The stiffness of the pavement is a critical design factor because it directly affects the load-bearing capacity of the road. In addition, early deterioration of the pavement due to rutting or fatigue cracking can be easily attributed to insufficient stiffness. The National Cooperative Highway Research Program (NCHRP) Project I-37A ("Development of the 2002 Guide for the Design of New and Rehabilitated Pavement Structures") recommends the use of dynamic modulus as a stiffness metric in mechanical design of pavements. While the dependence of pavement performance on stiffness is well known, this parameter is rarely measured during pavement construction. Instead, current field quality control during asphalt pavement construction focuses on measuring the density of the finished pavement at specific locations.

[0028] The methods and apparatus described herein provide a good quality control mechanism for use by a vibratory roller operator during the paving process, which provides a real-time representation of the quality of the entire pavement. In the disclosed embodiments, the vibratory roller operator utilizes the Reconstruction Intelligent Compaction Analyzer (RICA) device to identify and correct many of the problems mentioned above during the paving of the pavement, resulting in improved pavement quality so that the pavement can last its designed life. Such quality control operations during pavement construction not only advantageously improve the overall performance of the paving process, but also advantageously result in reduced construction and maintenance costs.

[0029] Figure 1 Schematic diagram 100 of a vibratory compactor or roller 110 retrofitted with a Retrofit Intelligent Compaction Analyzer (RICA) device 112 that can continuously measure the density of portions or sections of an asphalt pavement or road 114 in real time throughout the length of the pavement during its construction. In some embodiments, the RICA device 112 does not control any aspect of the behavior of the roller 110 and can be a stand-alone device that can be retrofitted to any type of existing vibratory compactor. In the embodiments described herein, the RICA device 112 obtains real-time measurements associated with the density of an asphalt mat at multiple locations on the pavement or road being constructed, determines an estimated compaction level, and then displays the estimated compaction level information to the operator of the roller 110 in a format that the operator can understand. The roller operator then uses the real-time measurement information to operate the roller in a manner that ensures uniform compaction, resolves undercompaction issues, and avoids overcompaction of the pavement or road.

[0030] Reference again Figure 1 In some embodiments, a vibratory compactor or roller 110 includes a front drum 120 and a rear drum 121. The front drum 120 includes an eccentric weight 126 mounted therein, and in some embodiments, both the front drum 120 and the rear drum 121 include an eccentric weight 126 mounted therein. The eccentric weight 126 is rotated by a motor (not shown) such that the rotation of the weight 126 within the drum 120 causes impacts at contact points between the drum 120 and the road surface 130. The road surface 130 may include hot mix asphalt (HMA), which may also be referred to as an asphalt pad. The spacing between impacts at the contact points is a function of the speed of the roller 110 and the speed of the eccentric weight 126 as the roller 110 moves along the road surface. For example, in some roller embodiments, there may be approximately ten to twelve (10-12) impulses or impacts per linear foot.

[0031] In some embodiments, the RICA device 112 is operably connected to a sensor module 122 mounted to a frame 128 of the vibratory roller 110. The sensor module 122 may be operably connected to a sensor module capable of measuring 10 g acceleration (or 98.07 meters per second squared; 98.07 m / s2 ) up to 10 kilohertz (kHz) frequency accelerometer 124, and may be operably connected to one or more infrared (IR) temperature sensors 125, which are shown here as being attached to the underside portion of the frame 128. The IR temperature sensors 125 measure the surface temperature of the road surface 130. Thus, in some embodiments during operation of the roller 110, the sensor module 122 measures the vibration of the vibratory compactor 110 and the IR temperature sensors 125 measure the surface temperature of the asphalt pad 130. Thus, the sensors 124, 125 associated with the sensor module 122 essentially comprise a real-time data acquisition system.

[0032] RICA device 112 may be a specially designed computer, or may be a modified or unmodified laptop or tablet computer, having a display screen 116 (which may be a touch screen) and a memory or storage device (not shown) containing computer executable instructions for providing a graphical user interface (GUI) (e.g., Figure 8 The GUI may be used to display a graphical user interface (shown in the figure) for viewing and use by an operator of the vibratory roller 110. The operator may use the GUI to, for example, specify and / or control the amplitude and frequency of the vibratory motor of the roller, and to input data such as asphalt pad characteristics, which may include, for example, mix type and paving thickness. The operator may also use the GUI to input data such as other initial input parameters, and may also view data such as sensor module output data.

[0033] In some embodiments, a global positioning system (GPS) 136 is mounted to the vibratory roller 110. The GPS 136 provides data indicating the location of the vibratory roller 110 as it moves during road construction, which location data may be used, for example, by the RICA device 112 so that the location of the generated density of one or more road segments AB, BC, CD, and / or DE of the road portion 132 will be recorded and / or known.

[0034] Figure 1 The RICA device 112 shown in FIG. 1 functions on the premise that the vibratory roller 110 and the underlying pavement material (e.g., hot mix asphalt (HMA)) of the road 114 form a coupled system. Therefore, the response of the vibratory roller 110 is determined by the frequency of its vibratory motor and the natural vibration modes of the coupled system. The compaction of the asphalt pad 130 increases its stiffness, and therefore, the vibration of the compactor can be varied as needed for different segments AB, BC, CD and / or DE to achieve a specified or desired compaction quality. Therefore, the characteristics of the pavement material and knowledge of the vibration spectrum of the compactor 110 can be used to estimate the compaction quality of the asphalt pad.

[0035] As discussed above, quality specifications for HMAs are typically specified as a percentage of air pockets, such that, for example, 100% density means that there are no air pockets, while 90% density means that there are 10% air pockets. Therefore, since quality specifications are typically specified as a percentage of air pocket content or a percentage of the theoretical maximum density (TMD) of the asphalt mat, in some embodiments, the RICA device 112 estimates the compacted density of the pavement for a particular portion of the road during construction and then displays the percentage on a display screen (see Figure 8 Item 806 in ), for the roller equipment operator to view. In the embodiment described herein, the estimate of the compaction density of the road surface is displayed in real time so that the operator of the roller 110 can decide whether a particular road segment requires additional compaction.

[0036] Figure 2 is a block diagram illustrating an example embodiment of a Retrofit Intelligent Compaction Analyzer (RICA) device 200 according to aspects of the present disclosure. The RICA device 200 may include standard components and / or custom designed and / or proprietary components in its hardware and / or architecture, and may be controlled by software and / or computer program instructions to operate as described herein. For example, the RICA device 200 may include server computer hardware.

[0037] like Figure 2 As shown, the RICA device 200 may include a RICA processor 202 operatively coupled to a communication device 204, an input device 206, an output device 208, and a storage device 210. The RICA processor 202, which may constitute one or more microprocessors, is also operatively coupled to a sensor module 212 and a global positioning system (GPS) device 214. In some embodiments, the sensor module 212 includes one or more accelerometers 216 and one or more infrared (IR) temperature sensors 218. The RICA processor 202 operates to execute the processor-executable steps contained in the program instructions described below, thereby controlling the RICA device 200 to provide the desired functions.

[0038] In some embodiments, the communication device 204 can be used to facilitate communication with, for example, other devices (e.g., server computers or handheld devices, such as tablet computers and / or smart phones that can be operated by construction personnel) and / or communication with one or more other rollers operated by different operators. For example, the communication device 204 may include multiple communication ports (not shown separately) to allow the RICA device 200 to communicate with multiple other computers and other devices simultaneously, including monitoring and / or recording compaction level data estimates related to the density and / or hardness of the soil, pavement, or road under the roller being driven by the operator and / or monitoring the communication required for the compaction level data estimates of the pavement or road under the second roller being operated by a different second operator. Such operation will ensure that two or more operators can work together to achieve the desired compaction level of a specific portion or multiple portions of the road. Therefore, the communication device can be configured for wireless communication and / or wired communication via various different types of networks (e.g., the Internet), and / or for communication via dedicated radio links, etc.

[0039] Input device 206 may include one or more of any type of peripheral devices commonly used to input data into a computer. For example, input device 206 may include components such as a keyboard, a mouse, and / or a microphone. Output device 208 may be, for example, a display component and / or a speaker and / or a printer. In some embodiments, input device 206 and output 208 include a touch screen.

[0040] The storage device 210 may include any suitable information storage device, including a combination of magnetic storage devices (e.g., hard drives), optical storage devices such as CDs and / or DVDs, and / or semiconductor storage devices such as random access memory (RAM) devices and read-only memory (ROM) devices, as well as flash memory and / or solid-state drives (SSDs), etc. Any one or more of such information storage devices may be considered to be a non-transitory computer-readable storage medium or computer-usable medium or memory.

[0041] The storage device 210 stores one or more computer programs for controlling the RICA device 200. The programs include program instructions (which may be referred to as computer readable program code means) comprising processor executable process steps of the RICA device 200, which are executed by the RICA processor 202 to cause the RICA device 200 to operate as described herein. For example, the programs may include one or more conventional operating systems (not shown) that control the RICA processor 202 to manage and coordinate activities and resource sharing in the RICA device 200 and act as a host for applications running on the RICA device 200. In addition, the storage device 210 may store a vibration energy application 220 that filters accelerometer data from one or more accelerometers 216 using fundamental frequency data and amplitude data obtained from sensors related to vibrations of a roller drum during compaction of a road surface as the roller drum moves in forward and backward directions on the road surface, and extracts average vibration energy data at each harmonic. In addition, the storage device may include a clustering application 222 that controls the RICA processor to normalize the average energy of harmonics in the accelerometer data and group the energy into a pre-specified or predetermined number of groups. In some embodiments, the storage device 210 may also store a percent theoretical maximum density (%TMD) application 224 that controls the RICA processor to correlate the estimated compaction level with one or more density measurements determined from cores that have been extracted from known locations and provide output data that can be used to display one or more output graphs (not shown) to an operator of the roller in real time while the roller is being compacted.

[0042] The storage device 210 may also store and the RICA device 200 may also execute other programs not shown. For example, such a program may include a compaction density estimation report application that controls the RICA processor 202 to transmit a density report about a predetermined length of road to a remote server computer (not shown) via the communication device 204. Other programs may also include, for example, one or more data communication programs, database management programs, device drivers, etc.

[0043] The storage device 210 may also store one or more databases 226 required for the operation of the RICA device 200. Such databases may include, for example, a database containing data regarding the grade of the mix, the estimated density at each location on the mat after each pass of the roller, the surface temperature of the mat during each pass of the roller, and / or the GPS coordinates of the roller and the corresponding time. In some embodiments, such data may be used, for example, to appropriately process sensor data from the sensor module and / or generate a compaction density estimate.

[0044] Reference again Figure 1, the roller 110 typically makes multiple passes over the asphalt mat 130 during road construction. The asphalt mat 130 may include a portion 132 of the road to be compacted having a defined length, for example, three hundred (300) feet. Thus, a location may be identified on the portion 132 of the road, represented here as Figure 1 132, each of which may be approximately seventy-five (75) feet long. These road locations may also be marked by the GPS device 136 during operation of the roller 110 and associated with the estimated density of the road portion 132 during compaction operations. In particular, as the drum 120 of the roller 110 makes multiple passes over the road section 132, the eccentric weights 122, 124 generate impacts and the responsive vibration signals of the drum 120 are sensed by the accelerometer 124 as the drum 120 moves along the road portion 132 and provided to the RICA processor 202. In addition to the temperature data obtained by the IR temperature sensor 124, this vibration data is also used to generate the compaction estimate as disclosed herein.

[0045] Figure 3A is a graph 300 depicting the vibration of the drum 120 of the roller 110 over time (here, from a starting point (zero; 0) to approximately 10 minutes) during each pass over a portion of the road surface to compact the asphalt road surface. Figure 3B is a spectrum diagram 350 of vibration, showing Figure 3A The frequency content (in Hertz) of the vibrations shown in . The graph shows sixteen (16) separate passes of the vibratory compactor over the asphalt mixture layer.

[0046] Figure 3B The fundamental frequency, which is the frequency of the rotating eccentric in the drum, is shown. The rotation of the eccentric mass results in an impulse force per revolution of the eccentric mass. Since the drum and the underlying pavement form a coupled system, both systems will exhibit a response to the input. The pavement layer undergoes viscoelastic-plastic deformation when the drum vibrates at the input frequency and its harmonics. An excitation frequency of 65 Hertz (Hz) will induce a response at 65 Hz and harmonics at 130 Hz, 195 Hz, 280 Hz, 325 Hz, and 390 Hz. Although the drum may exhibit a response at other frequencies, most of the vibration energy in response to the input is contained in the fundamental frequency and its harmonics. The power content of the vibration within a frequency band is related to the amplitude of the vibration and is expressed in decibels (db).

[0047] Figures 4A to 4F Graphs 410-460 are depicted which show the power contained in selected frequencies of drum vibration of a road roller. In particular, Figure 4A is a graph 410 showing the power of drum vibration at a frequency of 65 Hz (H); Figure 4Bis a graph 420 showing the power of drum vibration at a frequency of 130 Hz (H); Figure 4C is a graph 430 showing the power of drum vibration at a frequency of 195 Hz (H); Figure 4D is a graph 440 showing the power of drum vibration at a frequency of 280 Hz (H); Figure 4E is a graph 450 showing the power of drum vibration 450 at a frequency of 325 Hertz (Hz); and Figure 4F is a graph 460 showing the power of drum vibration at a frequency of 390 Hertz (H).

[0048] Figure 5 5 is a graph showing normalized power in fundamental frequency 500 according to an embodiment. For each frequency band, the vibration signal during compaction of the pavement layer test stretch is analyzed and the minimum (P min ) and maximum (P max ) power level. Given the instantaneous power P, the normalized power is calculated as 100*(PP min ) / (P max -P min ).

[0049] Figure 6 600 is a graph of the vibration response of a roller grouped into clusters according to some embodiments. The normalized power in each frequency band is grouped into clusters representing vibrations that reflect increasing levels of compaction. There are many algorithms that can be used to group these vectors representing the power in each frequency band, for example, k-means clustering, self-organizing maps, etc. The lowest power levels correspond to the situation where the roller is on an uncompacted asphalt mixture and therefore its response is attenuated. The highest power levels indicate that the material is well compacted and therefore the roller exhibits increased vibrations at all frequencies. The desired density estimate accuracy determines the number of clusters required. For example, 4 to 6 clusters are sufficient to achieve an accuracy within one percent (1%) of the actual density. Increasing the number of clusters increases the misclassification error, while too few clusters limits the accuracy achieved. In some embodiments, a low pass filter is used to interpolate between the density estimated from the clusters at each subsequent time step. In Figure 6 In the example shown, the vibration clusters include a first cluster 610 , a second cluster 620 , a third cluster 630 , a fourth cluster 640 , and a fifth cluster 650 .

[0050] Fig. 7A , 7B and 7C respectively illustrate the use of Figure 6Graphs 700, 710, and 720 of density estimates for three passes of a roller are provided for clustering information of the roller. In particular, in some embodiments, the RICA device 200 monitors the fundamental frequency of vibration of the roller during compaction as the roller moves in forward and backward directions over a road surface by filtering accelerometer data from one or more accelerometers using a set of filters and extracting the average vibration energy at each harmonic. Next, the RICA device 200 normalizes the average energy of the harmonics in the accelerometer data and groups the energy into a pre-specified or predetermined number of groups. In some embodiments, clustering techniques are used to group the energy data into five (5) different vibration groups, such as Figure 6 As shown. These five sets of vibrations can then be correlated to an estimated compaction level using a smoothing function. Next, the RICA device 200 correlates the estimated compaction level with one or more density measurements determined from cores that have been extracted from known locations so that the estimated compaction level can be expressed as a percent theoretical maximum density (%TMD).

[0051] Figure 8 Display screen output data 800 is shown that may be provided to a vibratory compactor 110 on a display screen 116 of a RICA device 112 retrofitted to a vibratory compactor according to the present disclosure (see FIG. Figure 1 ) operator. In some embodiments, the display screen data 800 includes a speedometer 802 or speed indicator indicating the speed of the vibratory compactor, a pad temperature gauge 804 indicating the pad temperature, and a density percentage readout 806 indicating the current density percentage. The operator can use control buttons 808 and 810 to switch between displaying data associated with the first roller and the second roller of the vibratory compactor, respectively. For a specific frequency of the eccentric, the roller speed determines the impact spacing on the asphalt pad. Speeds above the rated speed will increase the spacing between subsequent locations on the pad and will result in uneven compaction. Low speeds will reduce the spacing between subsequent impact locations and may result in over-compacting and damaging the pavement. Therefore, the speed indicator 802 and the pad temperature indicator 804 help the roller operator operate the roller within the desired operating range, which results in minimizing or reducing compaction differences caused by operator actions (or operator errors).

[0052] The thermometer 804 also includes the temperature ranges required for different roller operations. For example, the asphalt pad must be between 270-350 degrees Fahrenheit (or approximately 132-154.5 degrees Celsius) for breakdown (BD) rolling. Similarly, the asphalt pad must be between 200-250 degrees Fahrenheit (93-121 degrees Celsius) for intermediate (IR) rolling, and between 130-160 degrees Fahrenheit (54-71 degrees Celsius) for finishing rolling, respectively. These temperature ranges can be entered into the computer system for each job or compaction project to provide the operator of the vibratory roller with simple guidance as to when the asphalt pad is ready for compaction.

[0053] Graphs 812 and 814 display an indication of the compaction achieved in the roller passes. In some embodiments, the density estimates during each roller pass are displayed in the form of a color-coded graph. Each graph displays the path of the roller and the density estimated over the pass. The operator can study the coverage of the asphalt pad by stepping through previous passes to determine whether the roller has compacted each location on the pad and to view the level of compaction achieved. In addition, the graphs also provide a visual indication of the uniformity of compaction, as in some embodiments, locations with similar density estimates will be displayed in the same or identical colors. In addition, each of graphs 812 and 814 may also display the average density estimated over that particular pass and the uniformity of the compaction

[0054] [=(1 / (3*standard_deviation)*100].

[0055] In some embodiments, a first operator may use toggle buttons 808 and 810 to obtain pad temperature and density estimates for a second RICA-equipped roller operated by a second operator that may be operated in conjunction with a first roller (operated by the first operator). For example, a first roller equipped with a first RICA device operated by a first operator may be used to perform a crushing operation, or a first compaction pass of the roller on a newly placed hot asphalt pad. Next, a second operator operating a separate second roller equipped with a second RICA device may be required to perform compaction and finishing operations on the same portion of the road. In some embodiments, the second roller operator may utilize the second RICA device to obtain estimated compaction level data from the first RICA device regarding the operations performed by the first operator and the first roller. The obtained estimated compaction level data received from the first RICA device may then be used to display an estimated compaction level on a display screen of the second RICA device so that the second operator of the second roller can make a determination, for example, how fast the second roller should proceed and / or how much time the second roller should spend on a particular portion of the road to achieve the desired compaction results. Thus, the ability to view the compaction details of the second roller in real time along with the estimated compaction level from the first roller advantageously assists the second operator in coordinating the performance of the first and second rollers operating in conjunction to increase productivity.

[0056] Fig. 9 900 is a flow chart illustrating a method for providing an estimate of the compaction level of pavement material to an operator of a roller in real time according to some embodiments. In some embodiments, a retrofitted intelligent compaction analyzer (RICA) processor of a RICA device retrofitted to a roller receives 902 vibration energy data from a sensor module. The vibration energy data corresponds to an impact response of at least one roller of the roller during compaction of pavement material on a section of pavement. The RICA processor also receives 904 temperature data from the sensor module, which may be generated by at least one infrared temperature sensor on the section of pavement. The RICA processor then determines 906 an estimated compaction level of the section of pavement in real time based on the vibration energy data, the pavement material property data, and the temperature data, and then displays 908 a density level percentage of the section of pavement on a display device for viewing by the operator of the roller, wherein the density level percentage is based on the estimated compaction level. In some embodiments, the RICA processor also displays 910 on the display device an indication of the compaction uniformity achieved by the roller on the section of pavement.

[0057] In some embodiments, the RICA processor determines 906 an estimated compaction level by monitoring a fundamental frequency of vibration of a roller of a road roller as the roller moves in forward and rearward directions over a road surface during compaction, filtering accelerometer data from at least one accelerometer to extract average vibration energy at each harmonic, normalizing the average energy of the harmonics in the accelerometer data, and grouping the vibration energy into a predetermined number of vibration clusters. Additionally, in some embodiments, the RICA processor correlates data associated with the vibration clusters to an estimated compaction level by using a smoothing function. In some embodiments, the RICA processor correlates the estimated compaction level to one or more density measurements determined from cores that have been extracted from known locations, and then expresses the estimated compaction level as a percent theoretical maximum density (%TMD).

[0058] Reference again Fig. 9 In some embodiments, the process further includes at least one of the RICA processor storing 912 the estimated compaction level in a storage device and transmitting 914 the estimated compaction level to a remote server. In some embodiments, the RICA processor may also receive geospatial location data of the vibratory roller from a GPS device as the vibratory roller traverses the section of pavement, associate the geospatial location data with the estimated compaction level data, and then transmit the geospatial location data and the associated estimated compaction level data to the remote computer. Additionally, the RICA processor may then store the geospatial location data and the associated estimated compaction level data in the storage device.

[0059] Thus, the systems and methods disclosed herein advantageously provide a Retrofit Intelligent Compaction Analyzer (RICA) device that can be easily retrofitted to an existing roller, such as a vibratory compactor, and provide real-time compaction data to the operator of the roller. The roller operator can advantageously use the estimated compaction level information in real time during road construction and take corresponding actions. For example, if the compaction level information indicates that the required standard has not been achieved, the roller operator can take corrective measures that he or she deems necessary to achieve the desired compaction quality level during pavement construction, such as passing the roller's drum over a section of road again. Such actions advantageously save time and money compared to having to destroy a portion of the road that is later found to be defective.

[0060] As used herein, the term "computer" should be understood to include a single computer or two or more computers in communication with each other.

[0061] As used herein, the term "processor" should be understood to include a single processor or two or more processors in communication with each other.

[0062] As used herein, the term "memory" or "storage device" should be understood to encompass a single non-transitory memory or storage device or two or more memories or storage devices.

[0063] As used herein, a "server" includes a computer device or computer system that responds to a large number of service requests from other electronic devices.

[0064] The above description and illustration of the processes herein should not be construed as implying a fixed order for performing the process steps. Rather, the process steps may be performed in any feasible order, including performing at least some steps simultaneously and / or omitting elements or steps.

[0065] Although the present disclosure has been described in conjunction with specific exemplary embodiments, it should be understood that various changes, substitutions, and alterations apparent to those skilled in the art may be made to the disclosed embodiments without departing from the spirit and scope of the present disclosure.

Claims

1. A method for providing an estimate of the compaction level of a pavement material layer in real time, comprising: receiving vibration energy data from the sensor module by modifying the smart compaction analyzer processor, the vibration energy data corresponding to an impact response of at least one roller of the roller during compaction of pavement material on a section of pavement; receiving, by modifying the intelligent compaction analyzer processor, temperature data generated by at least one infrared temperature sensor above the section of pavement from the sensor module; By modifying the Intelligent Compaction Analyzer processor, the estimated compaction level of the pavement section is determined in real time by: monitoring a fundamental frequency of vibration of at least one roller of the roller during compaction as the at least one roller of the roller moves in a forward and backward direction over the section of road surface; extracting average vibration energy at each of harmonics of a fundamental frequency by filtering accelerometer data from at least one accelerometer; Normalize the average vibration energy of the harmonics in the accelerometer data; and grouping the average vibration energies at the fundamental frequency and harmonics into a predetermined number of vibration clusters representing frequency bands reflecting increasing levels of compaction, wherein a desired density estimate accuracy determines the predetermined number of vibration clusters; and The intelligent compaction analyzer processor is modified to display a density level percentage readout representing the estimated compaction level of the section of pavement on a display device for real-time viewing by the operator of the roller.

2. The method of claim 1 further comprising displaying on a display device an indication of the uniformity of compaction achieved by a roller passing over the section of pavement by modifying the intelligent compaction analyzer processor.

3. The method of claim 1 further comprising displaying an indication of the mat temperature on the section of pavement on a display device by modifying the intelligent compaction analyzer processor.

4. The method of claim 1 , further comprising correlating data associated with the vibration clusters to the estimated compaction level using a smoothing function by modifying the smart compaction analyzer processor.

5. The method according to claim 4, further comprising: correlating the estimated compaction level to one or more density measurements determined from cores extracted from known locations by modifying the intelligent compaction analyzer processor; and The Smart Compaction Analyzer processor was modified to express the estimated compaction level as percent theoretical maximum density (%TMD).

6. The method according to claim 1, further comprising at least one of the following: storing the estimated compression level in the storage device by modifying the intelligent compaction analyzer processor; and The estimated compression level is transmitted to a remote server computer by modifying the intelligent compaction analyzer processor.

7. The method according to claim 1, further comprising: By modifying the intelligent compaction analyzer processor to receive geospatial location data of the vibratory roller when it passes through the road section from the GPS device; Correlating geospatial location data with estimated compaction level data by modifying the Smart Compaction Analyzer processor; and The geospatial location data and associated estimated compaction level data are transmitted to a remote computer by modifying the intelligent compaction analyzer processor.

8. The method of claim 7, further comprising storing the geospatial location data and the associated estimated compaction level data in a storage device by modifying the smart compaction analyzer processor.

9. The method according to claim 1, further comprising: receiving, by the retrofitted intelligent compaction analyzer processor from a second retrofitted intelligent compaction analyzer processor of a second retrofitted intelligent compaction analyzer device associated with the second roller, a second estimated compaction level associated with operation of the second roller on the section of pavement; and The intelligent compaction analyzer processor is adapted to display a second density level percentage on a display device based on the second estimated compaction level for use by an operator of the roller to determine how to achieve a desired compaction level.

10. A retrofitted intelligent compaction analyzer apparatus for providing an estimate of the compaction level of a pavement material layer in real time, comprising: Modify the processor of the intelligent compaction analyzer; a communication device operably connected to the modified intelligent compaction analyzer processor; a display device operably connected to the modified intelligent compaction analyzer processor; a sensor module operably connected to a processor of the retrofitted intelligent compaction analyzer; and A storage device operably connected to a processor of the retrofitted smart compaction analyzer, wherein the storage device stores processor-executable instructions that, when executed, cause the processor of the retrofitted smart compaction analyzer to: receiving vibration energy data from the sensor module, the vibration energy data corresponding to an impact response of at least one roller of the roller during compaction of pavement material on a section of pavement; receiving temperature data from a sensor module, the temperature data generated by at least one infrared temperature sensor above the section of road surface; The estimated compaction level of the pavement section is determined in real time by: monitoring a fundamental frequency of vibration of at least one roller of the roller during compaction as the at least one roller of the roller moves in a forward and backward direction over the section of road surface; extracting average vibration energy at each of harmonics of a fundamental frequency by filtering accelerometer data from at least one accelerometer; Normalizing the average vibration energy of harmonics in the accelerometer data; and grouping the average vibration energies at the fundamental frequency and harmonics into a predetermined number of vibration clusters representing frequency bands reflecting increasing levels of compaction, wherein a desired density estimate accuracy determines the predetermined number of vibration clusters; and A density level percentage readout representing the estimated compaction level of the section of pavement is displayed on a display device for real-time viewing by the operator of the roller.

11. The modified intelligent compaction analyzer device according to claim 10, wherein: The storage device stores additional processor-executable instructions that, when executed, cause the retrofitted intelligent compaction analyzer processor to display on the display device an indication of compaction uniformity achieved by a rolling pass of the roller over the section of pavement.

12. The modified intelligent compaction analyzer device according to claim 10, wherein: The memory device stores additional processor-executable instructions that, when executed, cause the retrofit smart compaction analyzer processor to display an indication of the temperature of the mat on the section of pavement on the display device.

13. The modified intelligent compaction analyzer device according to claim 10, wherein: The storage device stores additional processor-executable instructions that, when executed, cause the processor of the retrofitted smart compaction analyzer to at least one of: storing the estimated compaction level in a storage device; and Transmits the estimated compression level to the remote server.

14. The retrofit smart compaction analyzer device of claim 10, further comprising a GPS device operably connected to the retrofit smart compaction analyzer processor, and wherein, The storage device stores additional processor-executable instructions that, when executed, cause the processor of the modified Smart Compaction Analyzer to: receiving geospatial location data of the vibratory roller as it traverses the section of road surface from a GPS device; associating geospatial location data with estimated compaction level data; and The geospatial location data and associated estimated compaction level data are transmitted to a remote server computer.

15. The modified intelligent compaction analyzer device according to claim 14, wherein: The storage device stores further processor-executable instructions that, when executed, cause the retrofit smart compaction analyzer processor to store the geospatial location data and the associated estimated compression level data in the storage device.

16. The modified intelligent compaction analyzer device according to claim 10, wherein: The storage device stores additional processor-executable instructions that, when executed, cause the processor of the modified Smart Compaction Analyzer to: receiving, from a second retrofitted intelligent compaction analyzer processor of a second retrofitted intelligent compaction analyzer device associated with a second roller, a second estimated compaction level associated with operation of the second roller on the section of pavement; and A second density level percentage is displayed on the display device based on the second estimated compaction level for use by an operator of the roller to determine how to achieve a desired compaction level.

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