The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lev Khazanovich - One of the best experts on this subject based on the ideXlab platform.
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establishing the interlayer structural response for unbonded Concrete overlays of existing Concrete Pavements
Transportation Research Record, 2018Co-Authors: Steven G Sachs, Julie M Vandenbossche, Derek Tompkins, Lev KhazanovichAbstract:An improved mechanistic empirical design procedure for unbonded Concrete overlays of existing Concrete Pavements (UBOLs) should account for the effect of the interlayer on the structural response of the pavement. One approach is to use the Totsky model to characterize the interlayer. The Totsky model treats the interlayer as a bed of springs between two plates and is currently incorporated into the rigid pavement finite element software ISLAB. A difficulty encountered in implementing this model is that there are currently no guidelines as to what the interlayer k-value should be for different types of interlayers. The interlayer can be constructed of new or aged asphalt (open or dense graded) or a nonwoven geotextile fabric. To establish the k-values that accurately characterize each of these materials, an ISLAB model of a laboratory test was created so the k-values could be established by matching the measured and calculated difference between the deflections in the overlay and existing pavement. To supp...
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effects of interlayer systems on reflective cracking in unbonded overlays of existing Concrete Pavements
Transportation Research Record, 2016Co-Authors: Steven G Sachs, Julie M Vandenbossche, Kevin Alland, John W Desantis, Lev KhazanovichAbstract:Reflective cracking can be a concern in unbonded Concrete overlays of existing distressed Concrete Pavements. In these structures, an interlayer, commonly hot-mix asphalt (HMA) or a nonwoven geotextile fabric, is placed to isolate the overlay Concrete from the existing Concrete pavement. The interlayer minimizes interaction between the overlay and the existing Concrete pavement, which helps prevent distress in the existing pavement from propagating into the overlay. In this study, a laboratory investigation was used to examine the influence of HMA and geotextile fabric interlayer systems on the potential for development of reflective cracking. A laboratory test was conducted by using stacked beam specimens separated by an interlayer to evaluate the potential for a discrete crack in the lower beam reflecting up through the interlayer and into the overlay beam. The study revealed that reflective cracking was more likely when there was loss of support beneath the existing pavement. Reflective cracking did no...
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ultrasonic tomography for evaluation of Concrete Pavements
Transportation Research Record, 2011Co-Authors: Kyle Hoegh, Lev KhazanovichAbstract:Ultrasonic tomography is an emerging technology that shows promise for quality assurance/quality control (QA/QC) during construction or for rehabilitation decisions about Concrete Pavements. However, the benefits of this emerging technology have not yet been fully captured for widespread use in highway infrastructure management. Verification of a state-of-the-art ultrasonic tomography device, MIRA, is presented through multiple field trials involving typical pavement constructability and rehabilitation issues. Field trials indicate that although the device is a useful portable pavement diagnostic alternative capable of consistent thickness measurement, reinforcement location, and distress evaluation, significant efforts and user expertise are required for measurement and data interpretation of large-scale application. Software was developed for a more productive, objective signal interpretation method with automated analysis of reinforcement location in continuously reinforced Concrete pavement. This type of automation for multiple applications shows promise for the use of ultrasonic tomography to improve large-scale pavement QA/QC and rehabilitation projects in the future. Nevertheless, the research in the paper shows ultrasonic tomography to be an accurate, reliable, and convenient alternative or supplement to traditional techniques that can be used for a wide variety of small-scale pavement diagnostics applications.
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evaluation of dowel alignment constructability in portland cement Concrete Pavements
Transportation Research Record, 2009Co-Authors: Shreenath Rao, Kyle Hoegh, Lev KhazanovichAbstract:Although dowel bars are an essential design feature of jointed Concrete Pavements to prevent pumping and faulting, few studies dealing with the constructability of dowel alignment have been conducted. With the emergence of the Magnetic Imaging Tools (MIT) Scan-2 as a non-destructive, robust method of locating dowels, it is now possible to efficiently evaluate the construction quality of dowel bar placement without damaging the newly constructed pavement. A brief review is presented of the results of recent field studies aimed at examining the constructability of doweled joints in Concrete Pavements. The dowel bar alignment data collected in this study encompass a wide range of design and environmental conditions and show that alignment within reasonable levels—considering equipment, mix design, as well as workmanship and consistency—is achievable in the field. Distress and performance analyses show that within these levels of misalignment, the pavement performance is not significantly affected. However, m...
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adaptation of mechanistic empirical pavement design guide for design of minnesota low volume portland cement Concrete Pavements
Transportation Research Record, 2008Co-Authors: Lev Khazanovich, Iliya Yut, Shariq Husein, Carly Turgeon, Thomas R BurnhamAbstract:A new Mechanistic-Empirical Pavement Design Guide (MEPDG) was recently proposed in the United States. The performance prediction models in the MEPDG were calibrated using nationwide pavement performance data. This study examined the feasibility of adapting a recent version of the MEPDG for the design of low-volume Concrete Pavements in Minnesota. To achieve this, a comprehensive evaluation of the MEPDG Version 0.910 performance prediction models was conducted. It was found that the faulting model produced acceptable predictions, whereas the cracking model had to be adjusted. Although performance data from the Minnesota Road Research facility were actively used in calibration of the MEPDG, it is necessary to perform calibrations against a wider range of local variables to achieve a practical design procedure for Minnesota. The cracking model was recalibrated using the design and performance data for 65 pavement sections located in Minnesota, Iowa, Wisconsin, and Illinois. A prototype catalog of recommended...
Julie M Vandenbossche - One of the best experts on this subject based on the ideXlab platform.
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establishing the interlayer structural response for unbonded Concrete overlays of existing Concrete Pavements
Transportation Research Record, 2018Co-Authors: Steven G Sachs, Julie M Vandenbossche, Derek Tompkins, Lev KhazanovichAbstract:An improved mechanistic empirical design procedure for unbonded Concrete overlays of existing Concrete Pavements (UBOLs) should account for the effect of the interlayer on the structural response of the pavement. One approach is to use the Totsky model to characterize the interlayer. The Totsky model treats the interlayer as a bed of springs between two plates and is currently incorporated into the rigid pavement finite element software ISLAB. A difficulty encountered in implementing this model is that there are currently no guidelines as to what the interlayer k-value should be for different types of interlayers. The interlayer can be constructed of new or aged asphalt (open or dense graded) or a nonwoven geotextile fabric. To establish the k-values that accurately characterize each of these materials, an ISLAB model of a laboratory test was created so the k-values could be established by matching the measured and calculated difference between the deflections in the overlay and existing pavement. To supp...
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effects of interlayer systems on reflective cracking in unbonded overlays of existing Concrete Pavements
Transportation Research Record, 2016Co-Authors: Steven G Sachs, Julie M Vandenbossche, Kevin Alland, John W Desantis, Lev KhazanovichAbstract:Reflective cracking can be a concern in unbonded Concrete overlays of existing distressed Concrete Pavements. In these structures, an interlayer, commonly hot-mix asphalt (HMA) or a nonwoven geotextile fabric, is placed to isolate the overlay Concrete from the existing Concrete pavement. The interlayer minimizes interaction between the overlay and the existing Concrete pavement, which helps prevent distress in the existing pavement from propagating into the overlay. In this study, a laboratory investigation was used to examine the influence of HMA and geotextile fabric interlayer systems on the potential for development of reflective cracking. A laboratory test was conducted by using stacked beam specimens separated by an interlayer to evaluate the potential for a discrete crack in the lower beam reflecting up through the interlayer and into the overlay beam. The study revealed that reflective cracking was more likely when there was loss of support beneath the existing pavement. Reflective cracking did no...
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methodology for identifying zero stress time for jointed plain Concrete Pavements
Transportation Research Record, 2014Co-Authors: Somayeh Nassiri, Julie M Vandenbossche, Donald J JanssenAbstract:This study focused on identifying the zero-stress time (TZ) in jointed plain Concrete Pavements (JPCPs). TZ is the time when the Concrete slab is sufficiently strong to deform (thermally expand or contract and thus curl) despite the existing external restraints, including the friction at the base-slab interface. It is critical to be able to identify TZ so that the temperature gradient present in the slab at TZ, known as the built-in temperature gradient, can be characterized. In this study, TZ was established through the instrumentation of 36 Concrete slabs in four JPCP construction projects. Strain-temperature behavior in each slab was used to identify TZ. The slabs in each project were paved at different times of the day (morning, noon, early afternoon, and late afternoon) to investigate the effects of the ambient curing conditions on TZ. The degree of hydration at TZ (αTZ) was established for each slab. The field data were used in the development of a model for predicting αTZ as a function of the concr...
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comparison of measured vs predicted performance of jointed plain Concrete Pavements using the mechanistic empirical pavement design guideline
International Journal of Pavement Engineering, 2011Co-Authors: Julie M Vandenbossche, Feng Mu, T R BurnhamAbstract:This research evaluates the ability of the Mechanistic–Empirical Pavement Design Guide (MEPDG) to accurately predict the performance of jointed plain Concrete Pavements (JPCPs). This is accomplished by comparing predicted performances with observed performances for the in-service mainline test cells at Mn/ROAD. These comparisons indicate that MEPDG performance predictions for JPCP are most accurate when the default (constant) built-in equivalent temperature difference of − 5.5°C is used instead of a site-dependent value. It appears that significant portions of the error of estimation can be explained by the sensitivity of the performance models to variability in hardened Concrete properties (modulus of rupture, modulus of elasticity and coefficient of thermal expansion) and pavement structural features (slab thickness, joint spacing, subbase type and bond condition). Predictions of slab cracking were found to be highly sensitive to these parameters. In addition, the MEPDG cracking model seemed not to fit ...
Steven G Sachs - One of the best experts on this subject based on the ideXlab platform.
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establishing the interlayer structural response for unbonded Concrete overlays of existing Concrete Pavements
Transportation Research Record, 2018Co-Authors: Steven G Sachs, Julie M Vandenbossche, Derek Tompkins, Lev KhazanovichAbstract:An improved mechanistic empirical design procedure for unbonded Concrete overlays of existing Concrete Pavements (UBOLs) should account for the effect of the interlayer on the structural response of the pavement. One approach is to use the Totsky model to characterize the interlayer. The Totsky model treats the interlayer as a bed of springs between two plates and is currently incorporated into the rigid pavement finite element software ISLAB. A difficulty encountered in implementing this model is that there are currently no guidelines as to what the interlayer k-value should be for different types of interlayers. The interlayer can be constructed of new or aged asphalt (open or dense graded) or a nonwoven geotextile fabric. To establish the k-values that accurately characterize each of these materials, an ISLAB model of a laboratory test was created so the k-values could be established by matching the measured and calculated difference between the deflections in the overlay and existing pavement. To supp...
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effects of interlayer systems on reflective cracking in unbonded overlays of existing Concrete Pavements
Transportation Research Record, 2016Co-Authors: Steven G Sachs, Julie M Vandenbossche, Kevin Alland, John W Desantis, Lev KhazanovichAbstract:Reflective cracking can be a concern in unbonded Concrete overlays of existing distressed Concrete Pavements. In these structures, an interlayer, commonly hot-mix asphalt (HMA) or a nonwoven geotextile fabric, is placed to isolate the overlay Concrete from the existing Concrete pavement. The interlayer minimizes interaction between the overlay and the existing Concrete pavement, which helps prevent distress in the existing pavement from propagating into the overlay. In this study, a laboratory investigation was used to examine the influence of HMA and geotextile fabric interlayer systems on the potential for development of reflective cracking. A laboratory test was conducted by using stacked beam specimens separated by an interlayer to evaluate the potential for a discrete crack in the lower beam reflecting up through the interlayer and into the overlay beam. The study revealed that reflective cracking was more likely when there was loss of support beneath the existing pavement. Reflective cracking did no...
Jun Zhang - One of the best experts on this subject based on the ideXlab platform.
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calculation of shrinkage stress in early age Concrete Pavements i calculation of shrinkage strain
Journal of Transportation Engineering-asce, 2013Co-Authors: Jun Zhang, Dongwei Hou, Yuan GaoAbstract:AbstractThis paper focuses on modeling of the distribution of shrinkage strain in early-age Concrete Pavements. In the modeling, an integrative model for autogenous and drying shrinkage predictions of Concrete at an early age is introduced first. Second, a model taking both cement hydration and moisture diffusion into account synchronously is used to calculate the distribution of the interior humidity in Concrete. The previous two models are experimentally verified independently by a series of shrinkage and interior humidity tests on three types of Concretes with different compressive strengths. Using the models, the distribution of shrinkage strain in early-age Concrete pavement (with respect to drying of the pavement surface) is calculated. The model results show the development of interior humidity inside of the pavement because the Concrete cast obeys a two-stage mode, i.e., a vapor-saturated stage with 100% relative humidity (Stage 1) and a stage with the relative humidity gradually decreasing (Stage...
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application of ductile fiber reinforced cementitious composite in jointless Concrete Pavements
Composites Part B-engineering, 2013Co-Authors: Jun Zhang, Zhenbo WangAbstract:Abstract This paper presents an experimental study on the potential applications of the fiber reinforced engineered cementitious composite with characteristic of low drying shrinkage (LSECC) in Concrete Pavements for the purpose of eliminating joints that are normally used to accommodate temperature and shrinkage deformation. It is found that a composite slab containing both plain Concrete and LSECC, with steel bars at the LSECC/Concrete interface, and designed construction procedures, it is possible to localize the tensile cracks into the LSECC strip instead of cracking in adjacent Concrete slab. The crucial problem that interfacial failure in composite slab was prevented by using reinforcing bars across the interfaces. Due to the strain-hardening and high strain capacity of the LSECC, the overall strain capacity and the integrity of the composite slab can be significantly improved. The temperature and shrinkage deformations can be accommodated by adequate selection on the length ratio of LSECC strip and Concrete slab.
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influence of supporting base characteristics on shrinkage induced stresses in Concrete Pavements
Journal of Transportation Engineering-asce, 2001Co-Authors: Jun ZhangAbstract:This paper presents an analytical model for prediction of shrinkage-induced stresses and displacements in Concrete Pavements due to the restraint of the supporting base. The model relies upon the interfacial friction stress transmitted between the slab and base as the fundamental mechanism of restrain provided by the base when Concrete shrinks. By analyzing experimental results reported in the literatures, a bilinear relation describing the friction stress-slippage behavior of the slab/base interface is adopted in the model. Closed-form expressions of shrinkage stresses and displacements in the Concrete slab are obtained. The model quantifies the effects of Concrete properties and the interfacial characteristics of the Concrete slab and base on the shrinkage stresses and displacements. By applying the slab/base frictional stress-slippage relation of seven typical supporting bases in the model, the influences of the supporting base on the development of shrinkage stresses and displacements in the Concrete slab are invetigated. In addition, the effect of “bond breaker” layers on the shrinkage stresses in the Concrete slab lying on a hot mix asphalt Concrete base is studied with the model.
Dan G Zollinger - One of the best experts on this subject based on the ideXlab platform.
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investigating the effects of curing quality on key Concrete pavement surface properties
Transportation Research Record, 2019Co-Authors: Alireza Joshaghani, Richa Bhardwaj, Dan G Zollinger, Anol MukhopadhyayAbstract:The large surface-area-to-volume ratio of Concrete Pavements increases moisture loss through evaporation during placement and hydration. Moreover, ambient conditions might expedite water evaporatio...
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finite element modeling and calibration of temperature prediction of hydrating portland cement Concrete Pavements
Journal of Materials in Civil Engineering, 2006Co-Authors: Dan G Zollinger, Jinhoon JeongAbstract:The temperature profiles in a hydrating Concrete slab are produced by a two-dimensional finite-element method software tool, TMAC 2 temperature and moisture analysis for curing Concrete, as a function of time and ambient boundary conditions described in this paper. To include the effect of the heat of vaporization, heat flux due to evaporation is included in the boundary condition of heat transfer at the slab surface in addition to the effects of surface humidity, effective curing thickness, and surface moisture emissivity on the rate of evaporation. Thermal conductivity is back-calculated using the data collected from laboratory measurements toward the improvement of the modeling of thermal conductivity. Theoretically, the material properties determined in this manner should facilitate accurate tempera- ture prediction. Thus, temperature prediction in hardening Concrete Pavements under various conditions can be effectively calibrated by improved material characterization. To this end, this paper provides the basis of a calibration protocol.
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environmental effects on the behavior of jointed plain Concrete Pavements
Journal of Transportation Engineering-asce, 2005Co-Authors: Jinhoon Jeong, Dan G ZollingerAbstract:A Concrete slab was constructed at Texas A&M University to investigate environmental effects in terms of temperature and moisture effects on the behavior of jointed plain Concrete Pavements. The slab behavior was delineated relative to equivalent linear temperature and humidity differences as a function of time. As expected, the trends of these differences were found to relate with the trends of ambient temperature and relative humidity. The slab had daily periods of tensile and compressive strain corresponding to the daily changes in the ambient temperature and relative humidity. Furthermore, the trends in the slab displacements were clearly dependent upon the changes in ambient temperature and slab temperature gradients. Drying shrinkage and creep strains primarily in the vicinity of the top surface appeared to cause an overall shift in the slab movements. This shift manifest in both the strain and vertical displacement of the slab was determined from data collected up to 2 years after placement of the Concrete.
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development of a mechanistic empirical structural design procedure for continuously reinforced Concrete Pavements
Transportation Research Record, 2004Co-Authors: Olga Selezneva, Dan G Zollinger, Michael I Darter, Lev KhazanovichAbstract:The concepts and approach used to develop a mechanistic-empirical structural design procedure for continuously reinforced Concrete Pavements (CRCP) are presented. Key aspects of the CRCP design procedure— including design overview, design inputs, structural response model, incremental damage analysis, and prediction of CRCP deterioration— are addressed. The mechanism of punch-out development is the foundation of the structural design procedure. Punch-out development is modeled by using mechanistic principles and damage accumulation over the design life. The incremental damage is used to account for changes in many factors throughout the entire design period, including material properties (portland cement Concrete strength and modulus, erosion of base), seasonal climatic conditions, traffic loadings, crack load transfer, subgrade support, and others. Each analysis increment represents a specific combination of these factors during a selected period of time. Finally, accumulated damage is correlated with CR...