Browsing by Author "Katicha, Samer W."

Now showing 1 - 11 of 11
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    Analysis of Repeated Network-Level Testing by the Falling Weight Deflectometer on I-81 in the Virginia Department of Transportation's Bristol District
    Bryce, James M.; Katicha, Samer W.; Diefenderfer, Brian K.; Flintsch, Gerardo W. (Virginia Transportation Research Council, 2016-11)
    This study was undertaken in an effort to determine the required time between subsequent rounds of network-level pavement deflection testing using a falling weight deflectometer (FWD) on the Virginia Department of Transportation’s (VDOT’s) interstate system. Network-level deflection testing was conducted in two separate years (2006 and 2011) on Interstate 81 in VDOT’s Bristol District. The testing was conducted using the FWD at an interval of 0.2 miles in the right-hand lane (travel lane) of the interstate. The objective of this study was to analyze the results from the 2011 testing and compare them to the results obtained from the 2006 study to determine if the previously completed FWD survey of VDOT’s entire interstate network needed to be repeated. First, deflection values that were obtained from pavement segments that received treatments between the two sets of tests were identified and omitted from any comparison. Second, the two datasets were compared directly (i.e., without accounting for errors) and were modeled to account for the expected errors in the data defined as the root mean square of the difference between 2006 and 2011 measurements. The results of the 2011 testing showed lesser deflection and greater structural number values when compared to the data collected in 2006. A characterization of the errors implicit in each set of measurement showed that the errors outweigh the changes in deflection values from the two datasets. Therefore, it was not possible to quantify a recommended time between subsequent rounds of deflection testing on the pavement network. Since the literature shows significant benefits to conducting pavement deflection testing on the network, VDOT will continue this practice based on local needs and as budgetary constraints allow.
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    Continuous Friction Measurement Equipment As a Tool for Improving Crash Rate Prediction: A Pilot Study
    de León Izeppi, Edgar; Katicha, Samer W.; Flintsch, Gerardo W.; McCarthy, Ross; McGhee, Kevin K. (Virginia Transportation Research Council, 2016-01)
    A comprehensive pavement management system includes a Pavement Friction Management Program (PFMP) to ensure pavement surfaces are designed, constructed, and maintained to minimize friction-related crashes in a costeffective manner. The Federal Highway Administration’s (FHWA) Technical Advisory 5040.38 on Pavement Friction Management supersedes a previous advisory that focused on skid crash reduction. In addition to traditional locked-wheel friction-testing devices, this new advisory recommends continuous friction measuring equipment (CFME) as an appropriate method for evaluating pavements. The study described in this report developed a pavement friction inventory for a single construction district in Virginia using the Grip Tester, a low-cost CFME. The continuous friction data were then coupled with crash records to develop a strategy for network analysis that could use friction to improve the ability to predict crash rates. The crash rate analysis applied the well-established methodology suggested by the FHWA for the identification of high crash risk areas using safety performance functions (SPFs), which include empirical Bayes rate estimation from observed crashes. The current Virginia Department of Transportation SPF models were modified to include skid resistance and radius of curvature (interstate and primary system only) to improve the predictive power of the models. A variation of the same methodology was also used to contrast the effect of two different friction repair treatments, i.e., conventional asphalt overlay and high friction surface treatments, to explore how their strategic use can impact network level crash rates. The result suggests significant crash reductions with comprehensive economic savings of $100 million or more when applied to a single relatively rural district. These findings easily justify an aggressive state-level PFMP and further support continued research to quantify the influence of other pavement-related characteristics such as macrotexture, grade, and cross-slope.
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    Developing a Network-Level Structural Capacity Index for Structural Evaluation of Pavements
    Bryce, James M.; Flintsch, Gerardo W.; Katicha, Samer W.; Diefenderfer, Brian K. (Virginia Center for Transportation Innovation and Research, 2013-03-01)
    The objective of this project was to develop a structural index for use in network-level pavement evaluation to facilitate the inclusion of the pavement's structural condition in pavement management applications. The primary goal of network-level pavement management is to provide the best service to the users for the available, often limited, resources. Pavement condition can be described in terms of functional and structural condition. The current widespread practice of network-level pavement evaluation is to consider only the functional pavement condition. This practice results in suggested treatments that are often under-designed or over-designed when considered in more detail at the project level. The disagreement can be reduced by considering the structural capacity of the pavements as part of a network-level decision process. This study developed a flexible pavement structural index to use for network-level pavement applications. Available pavement condition data were used to conduct a sensitivity analysis of the index, and example applications were tested. The results indicated that including the structural index developed, named the Modified Structural Index (MSI), into the network-level decision process minimized the discrepancy between network-level predictions and project-level decisions when compared to the current network-level decision-making process. A pilot implementation of the MSI showed that it can be used to support various pavement management decision processes, such as network-level structural screening, deterioration modeling, and development of structural performance measures. The pilot test also indicated that the impact of the structural condition of the pavement on the performance of a maintenance treatment and its impact on life-cycle costs can be quantified.
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    Development of structural condition thresholds for TSD measurements
    Shrestha, Shivesh (Virginia Tech, 2017)
    This thesis presents (a) results of a field evaluation of the Traffic Speed Deflectometer (TSD) in the United States (b) deflection thresholds to classify the pavement structural condition obtained from the TSD for a small subset of the Pennsylvania secondary road network. The results of the field evaluation included: (1) repeatability of the TSD, (2) ability of the TSD to identify pavement sections with varying structural conditions, and (3) consistency between the structural number (SNeff) calculated from the TSD and SNeff calculated by the Pennsylvania Department of Transportation (PennDOT). The results showed consistent error standard deviation in the TSD measurements and that the TSD was able to identify pavement sections that varied in structural condition. Comparison of the SNeff calculated with TSD measurements, using an empirically developed equation by Rohde, with the SNeff calculated by PennDOT’s Pavement Management System based on construction history showed similar trends, although the TSD-calculated SNeff was higher. In order to develop deflection thresholds, a model that related the pavement surface condition to pavement surface age and structural condition was developed. Structural condition thresholds were then selected so that the pavement surface condition predicted from the model for a 10-year-old pavement surface fell within one of the three condition categories (Good, Fair, and Poor), to identify pavements in good, fair and poor condition. With Overall Pavement Index(OPI) characterizing the surface condition and Deflection Slope Index(DSI) characterizing the structural condition, the DSI threshold that separates structurally good from structurally fair pavements was determined as follows: (1) the OPI threshold that separates pavements with good surface condition from those with fair surface condition was obtained from the Pennsylvania Pavement Management System (PMS) and (2) the DSI thresholds were calculated using the determined OPI value and the model equation.
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    Instrumented Response and Multilayer Modeling of Cold-Central Plant Recycled Pavement Section
    Benavides Ruiz, Carolina (Virginia Tech, 2021)
    During the last two decades, environmental awareness and climate change concerns have encouraged and supported the implementation of recycled techniques in the Transportation Infrastructure Industry for rehabilitating and constructing pavements in the United States. Besides that, pavement roads are public goods that bring economic and social benefits to all countries. Therefore, assessing the pavement structural condition is essential to understand the performance of new materials and determine actions for conservation, maintenance, or rehabilitation. In-situ Pavement monitoring through embedded instrumentation is a type of monitoring technique, which uses several sensors installed within the pavement to obtain the structural responses used in Mechanical-Empirical design to control the performance and define asset management plans. This thesis presents the instrumented response of a Recycled Pavement Section on the Interstate 64 (located in Virginia, USA) to analyze the actual pavement responses (strain and stress) under real traffic and environmental conditions. Several sensors were installed during the construction (including strain gauges, pressure cells, thermocouples, and TDR probes), and two recycling techniques were used (CCPR and Full Depth Reclamation (FDR)) in this project. The Instrumented Recycled Pavement Section analyzed in this research was tested during five months in 2019 to evaluate the effect of temperature, sensor location, and load configuration on the pavement responses collected in the field. During the tests, three loaded trucks ran over the instrumented section. The results showed that the pavement structure is working properly, the stress responses decreased with depth, the maximum strain over the months was compared, and the temperature effect was addressed. Nevertheless, the stress and strain data obtained in each test presented a large variability because it is difficult to control the position where the trucks are passing during this type of experiment. Furthermore, the measured strains were useful to develop a calibrated pavement structural model, which showed that the pavement is expected to have a long structural service life.
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    Latest Development in the Processing of Pavement Macrotexture Measurements of High Speed Laser Devices
    Katicha, Samer W.; Mogrovejo, Daniel E.; Flintsch, Gerardo W.; de León Izeppi, Edgar; Carrasco, Daniel M. (2015-06-04)
    Pavement macrotexture is an important property that affects tire-pavement interactions like friction, tire pavement noise, splash and spray, and rolling resistance. Macrotexture measurement is generally divided into two classes: static measurements and dynamic measurements. Dynamic measurements are performed with vehicle mounted lasers that measure macrotexture at traffic speed. One drawback of these laser devices is the presence of "spikes" in the collected data which causes erroneous texture measurements. In this paper, we develop a data driven adaptive method that detects and removes the spikes from high speed laser texture measurements. The method is based on the discrete wavelet transform and can be summarized in the following three steps: (1) calculate the discrete wavelet transform of texture measurements, (2) detect and remove the "spikes" from the obtained wavelet coefficients, and (3) calculate the inverse discrete wavelet transform with the processed wavelet coefficients to obtain Mean Profile Depth (MPD) measurements with the "spikes" removed. The crucial step in the proposed method is step 2 which we detail in this paper. We compare the results of calculated MPD obtained by removing the "spikes" with the proposed method with the results obtained without removing the "spikes", and validate the proposed method with MPD measurements obtained with a Circular Texture Meter (CTMeter).
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    Multivariate Volumetric Specifications and Dynamic Modulus as a Quality Measure for Asphalt Concrete Materials
    Katicha, Samer W.; de León Izeppi, Edgar; Flintsch, Gerardo W. (Virginia Center for Transportation Innovation and Research, 2010-06-01)
    The Virginia Department of Transportation (VDOT) has worked toward end-result specifications (ERSs) in asphalt concrete since the mid-1960s. As stated by Hughes et al. (2007), true ERSs can lead to a reduction in VDOT's overall inspection force resulting in considerable savings and allow for the reallocation of inspection resources to key construction and placement processes that cannot be measured upon delivery (e.g., joint tacking and construction platform preparation). The latest efforts toward this end were conducted by Hughes et al. (2007) who suggested expanding the quality measures for asphalt concrete acceptance to include the asphalt concrete volumetric properties of voids in total mix (VTM) and voids in mineral aggregates (VMA), along with the already used asphalt content (AC) and gradation. This report builds on that and further investigates, through the use of the asphalt concrete dynamic modulus, how performance-related ERSs can be introduced into a quality assurance (QA) plan. Specifically, the report 1) documents the current variability of VTM, VMA, and AC; 2) explores different QA specification plans; and 3) develops and applies a method to predict asphalt concrete rutting performance from asphalt concrete dynamic modulus test results using the mechanistic-empirical pavement design guide (MEPDG). Contractor volumetric test results (for the years 2006 through 2008) for VTM, VMA, and AC were obtained from VDOT's central database for production asphalt concrete. Statistical measures of mean, variance and covariance were calculated. The experimental distribution of test results for each of the three volumetric measures was obtained and compared to the normal (Gaussian) distribution. This research used these data and exploratory analysis to present alternative QA plans, which ranged from a simple univariate plan to a multivariate percent within limits (PWL) plan. The choice of a specific plan to implement depends, among other criteria, on the variable-more specifically on the correlation between these variables-that are included as part of this plan. The PWL method for uncorrelated variables (in this case VTM and AC) is recommended as it presents a sound statistical approach that avoids the complexities that result from incorporating correlated variables. With advances in mechanistic-empirical pavement design methods (specifically the new MEPDG), a framework for performance-related ERSs is now available. The dynamic modulus as a function of temperature and frequency is the main asphalt concrete material input property in the MEPDG. It has significant influence on distress prediction, which makes it a quality candidate test for performance-related ERSs. A principal technical barrier to using the dynamic modulus test is the time required to perform the test temperature sweep. To address this obstacle, this report presents a method to reduce the required number of tests to characterize asphalt concrete rutting characteristics. It demonstrates that a single dynamic modulus test is sufficient to estimate asphalt concrete rutting potential as calculated by the MEPDG. This is an initial step towards using the dynamic modulus in performance-related ERSs. However, actual implementation still depends on broader acceptance and use of the dynamic modulus testing equipment and procedures, as well as the proper calibration of the MEPDG distress models to reflect observed field performance. If and when this is accomplished, the method can be extended to fatigue cracking.
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    Network Level Structural Evaluation with the TSD device
    Katicha, Samer W. (2014-09-17)
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    Ride Quality Assessment Using Probe Vehicle Acceleration Measurements
    Katicha, Samer W.; Flintsch, Gerardo W.; Valeri, Stephen M. (2012)
    New vehicle technology is leading to efficient methods for assessing the condition of the national highway system. Utilizing simple sensors installed in vehicles, such as accelerometers, could provide a cost effective way to assess ride quality for pavement management. This paper builds on a pilot study that compared data gathered from accelerometers to the current state of the art practices for measuring ride quality. After promising results with preliminary acceleration data, robust data collection was performed on the Virginia Smart Road under various operational conditions and using two vehicles: a Volvo truck and a Ford Fusion using the DAS system developed by the Virginia Tech Transportation Institute. Profile measurements were also obtained for comparison using an inertial laser profiler. Tests were performed at 40, 50, and 65 mph (65, 80, and 105 km/h). A GPS device was used to accurately calculate vehicle position and speed. Repeatability of acceleration and profile measurements were calculated. Effect of vehicle type and testing speed on the acceleration profile was estimated. Results show that under controlled testing conditions, roadway roughness can be accurately estimated using probe vehicle acceleration data. This suggests that instrumented probe vehicles might be a viable and effective way of implementing a pavement condition assessment program in the near future.
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    Splash and Spray Assessment Tool Development Program: Final Report
    Flintsch, Gerardo W.; Tang, Lijie; Katicha, Samer W.; de León Izeppi, Edgar; Viner, Helen; Dunford, Alan; Nesnas, Kamal; Coyle, Fiona; Sanders, Peter; Gibbons, Ronald B.; Williams, Brian M.; Hargreaves, David; Parry, Tony; McGhee, Kevin K.; Larson, Roger M.; Smith, Kelly L. (Virginia Tech. Virginia Tech Transportation Institute, 2014-10-07)
    The effects of vehicle splash and spray are well known to motorists who have driven in wet weather conditions. Research suggests that splash and spray contribute to a small but measurable portion of road traffic accidents and are the source of considerable nuisance to motorists. Splash and spray from highway pavements also can carry a number of pollutants and contaminants. When deposited, these contaminants can be poisonous to plant life and accelerate the corrosion of roadway appurtenances. Splash and spray are individually definable processes that are the product of a number of different factors. Many parties have gone to great lengths to reduce the splash and spray created by motor vehicles, especially that from heavy vehicles, by retrofitting devices that alter the vehicle’s aerodynamics. Another possible solution to the problem is to change the characteristics of the highway pavement. Previous research shows that pavement geometry, drainage, texture, and porosity all contribute to splash and spray generation, but the exact mechanisms are largely unknown. A model capable of predicting the splash and spray propensity of pavements can be used by highway engineers to support decisions in highway maintenance and design. The project objective was to develop a simple and practical assessment tool to characterize the propensity of highway sections to generate splash and spray during rainfall and the impact of splash and spray on road users. This report summarizes the development of the splash and spray model and its implementation in an easy-to-use, practical tool.