Browsing by Subject "Pavement"

Now showing 1 - 15 of 15
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    10th Annual Minnesota Pavement Conference: Session Summaries
    (Center for Transportation Studies University of Minnesota, 2006-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota roads
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    11th Annual Minnesota Pavement Conference: Session Summaries
    (Center for Transportation Studies University of Minnesota, 2007-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota roads
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    12th Annual Minnesota Pavement Conference: Session Summaries
    (Center for Transportation Studies University of Minnesota, 2008-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota roads.
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    13th Annual Minnesota Pavement Conference: Session Summaries
    (Center for Transportation Studies University of Minnesota, 2009-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota roads
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    15th Annual TERRA Pavement Conference: Session Summaries
    (Center for Transportation Studies, University of Minnesota, 2011-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota roads.
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    2010 TERRA Pavement Conference: Session Summaries
    (Center for Transportation Studies, University of Minnesota, 2010-02) Center for Transportation Studies
    This one-day conference provides information to practitioners and others in pavement design, construction, and maintenance. The emphasis of the conference is new materials and methods that can assist decision-makers in providing the most cost-effective strategies for building, repairing, and maintaining Minnesota road
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    Development Of A Comprehensive Backcalculation Procedure For Rigid Pavement Design Parameters Using Slab-Edge Deflection Basins
    (2016-06) Paitich, Samuel
    Backcalculation of structural parameters for rigid pavements is commonly conducted with falling weight deflectometer (FWD) deflection basins measured at the center of slabs. Although a number of established techniques exist to backcalculate pavement parameters for the slab-center location, a reliable technique to backcalculate such parameters at the neighboring slab-edge location does not exist. The slab-edge location is critical to the design and management of rigid, concrete pavements because high stress levels and early signs of degradation originate at the slab edge. An edge backcalculation procedure accounting for the load transfer efficiency (LTE) of inter-slab joints is developed in this study. The proposed procedure is based on finite element modeling and dimensional analysis. Testing and validation of the edge backcalculation procedure is performed using FWD basins measured at the slab-edge location of in-situ pavements, along with measured LTEs, via the Long Term Pavement Performance (LTPP) program. Some prospective applications of the new procedure, in conjunction with the LTPP database, are presented. It is shown that the new edge backcalculation procedure is robust and satisfactory, particularly for pavements in good structural condition.
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    Dynamic Analysis of Slab-on-Grade Systems: Forward and Backcalculation Analyses
    (2017-12) Booshehrian, Abbas
    The problem of calculating the response of a slab-on-grade is of interest for analysis and design of industrial floors, nuclear plants, mat and raft foundations, and pavement systems. These structures are often subjected to complicated external dynamic excitations such as earthquakes, impacts, and moving loads, resulting in a challenging load-structure system to simulate. For design and evaluation purposes, deflection-based non-destructive testing such as falling weight deflectometer (FWD) is often utilized to obtain the design properties of these structures. Typically, this is done in two stages: I) forward analysis in which a mathematical model is used to generate the response of the system to a known FWD load, given the structural properties, and II) inverse analysis (a.k.a. backcalculation) in which a numerical scheme is used to indicate the structural properties, given the response of the system to the known FWD load. The objective of this study was to develop a computational method based on the plate-ona-foundation approach to model and characterize the slab-on-grade structures subjected to a short-duration dynamic axisymmetric pressure induced by FWD. The advantage of this approach is that it is simple, efficient, and applicable to both elastic and viscoelastic slabs. Furthermore, this approach is compatible with the recently-developed analysis which estimates the excess vehicular fuel consumed due to the viscous deformation of the pavement under the moving load. Thereby, in addition to the applications for the design and analysis of structures, the backcalculated properties may be employed as inputs for realistic evaluation of the environmental impacts caused by the additional fuel use. To do so, an efficient numerical forward-solution in the time-domain was developed for the response of a thin and infinite viscoelastic Kirchhoff-Love plate resting on a foundation by making use of a Hankel transform in space and a finite difference method in time. Then, the shortcomings of the traditional foundation models, such as the Winkler, Pasternak, and Vlasov models, in capturing the dynamic behavior of the system were highlighted, and required modifications were made. Next, a gradient-based optimization scheme was employed in conjunction with the forward-solution to develop a fast and reliable dynamic backcalculation. To showcase the ability and applications of the developed analysis, multiple case studies were carried out using the data recorded by the FWDs tested on asphalt and concrete pavements. Finally, the traditional Vlasov foundation model was modified accordingly to accommodate the dynamics of the structure. This reinforced the analysis with the ability to characterize the foundation in addition to the top slab.
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    Effects of Seasonal Changes on Ride Quality at MnROAD
    (Minnesota Department of Transportation, 2008-07) Khazanovich, Lev; Bly, Peter; Shamin, Atika; Barnes, Randal J.
    This project studied frost heave as it relates to different pavement design parameters and ride quality deterioration. Elevations of frost pins embedded in MnROAD test sections were measured over four years. Pin elevation changes were analyzed to show the amount of frost heave and degree of frost heave uniformity within a cell. Various plots were made to show the elevation change and interquartile range of the pins over time. Statistical approaches such as visual analyses, Student-t hypothesis testing, and ANOVA analysis were used in this study to evaluate the effect of pavement design features on frost heave and roughness. Subgrade and base type, pavement thickness, and drainage capabilities are the major design factors that affect frost heave. The effects of frost heave on ride quality deterioration for flexible and rigid pavements could not be confirmed or statistically rejected in this study. No seasonal adjustment factor for IRI measurement is recommended for use in a pavement management system because no firm conclusions could be made from the data concerning a seasonal effect on IRI measurements.
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    Field And Laboratory Evaluation of Asphalt Crack Sealant Performance
    (2020-05) Munch, Jared
    Crack sealing on hot-mix asphalt (HMA) pavement roads is a pavement maintenance technique used to limit the intrusion of water into the pavement structure, and thereby, delay additional distresses. There are two commonly used methods of crack sealing in Minnesota: (i) clean-and-seal, and (ii) rout-and-seal. Since roads in Minnesota are extremely susceptible to cracking in the transverse direction, the goal of this study was to provide insight to the most effective method of crack sealing on asphalt pavements. Based on the field performance results, this study compared the abovementioned two methods for difference scenarios and developed a decision tree to identify the most effective crack sealing method for a given condition of pavement and traffic. As an additional component to the primary study, a new testing procedure for evaluating the adhesiveness between the sealant material and the HMA matrix was developed. This procedure tests sealant materials in tension to produce a stress/strain curve of the sealant as it fails.
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    Impact of asphalt mixture design parameters on transverse cracking performance and laboratory testing results
    (2015-04) Helmer, Benjamin William
    In cold climate regions, thermal cracking of asphalt pavements is a primary pavement distress. Cold climates cause thermal contraction within the pavement. When combined with the brittle behavior of asphalt at low temperatures, the thermally induced stresses are relieved by transverse cracks forming in the pavement. This cracking facilitates poor ride quality and premature failure of the pavement. There is currently no asphalt mixture performance test required by a majority of Department of Transportations (DOTs) in the United States to address the issue of thermal cracking. Previous research has indicated that fracture energy of asphalt mixtures is a reliable predictor of transverse cracking performance. This mechanistic property of asphalt mixtures can be found using the disk-shaped compact tension (DCT) test. On basis of previous research, a low-temperature cracking performance specification that uses DCT fracture energy has been developed. This project focused on eighteen highways containing twenty-six separate study sections. The projects encompassed different construction techniques, material compositions and climatic zones. The results from field studies, analysis of the mix parameters for each section and laboratory testing for sections are presented in this document. The results provide validation for previous research that suggests the use a performance test is vital to accurate projection of roadway transverse cracking performance. Other findings include reaffirmation of common knowledge about various mix parameters that suggest increasing or decreasing values will have positive and negative effects on both cracking amounts and performance testing. In nearly all instances, sections with an overlay construction type performed inferior to reclaimed construction types. For example, reclaimed sections exhibited roughly one-third the average transverse cracking amount of overlay sections. This phenomenon will be monitored in future studies.
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    Improvement of Asphalt Mixture Design for Cold Climatic Region
    (2024-02) Manickavasagan, Vishruth
    Asphalt material is widely used for roadways in the United States, underscoring its crucial role in the country's transportation infrastructure. In cold climatic regions such as Minnesota, the asphalt pavement undergoes significantly low-temperature cycles in winter resulting in shrinkage of the asphalt, which leads to thermal cracking, and subsequently potholes. The present study explores the behavior of asphalt mixes with an emphasis on improving the resistance of the mixes against low-temperature thermal cracking. The study included high and low-density mixes and considered the impact of polymer-modified asphalt binders. In the first phase of the study, seven asphalt mixes were designed and tested, with three using the conventional Superpave (Superpave-4) mix design method, three utilizing the Superpave-5 mix design method for high-density asphalt mixes and one using regressed air-void method for a reference. In the second phase, eight asphalt mixes were tested, with four using polymer-modified binder and four using non-polymer-modified binder. The Disc-Shaped Compact Tension (DCT) test, Indirect Tensile Strength (ITS), and Dynamic Modulus (DM) tests were conducted to study the performance of the mixtures. From the test results, it was found that the Superpave-5 mix design samples containing polymer-modified binders exhibited better fracture properties or higher resistance to low-temperature thermal cracking compared to the Superpave-4 mixes, with non-polymer modified binder. The study further explores other relevant behaviors of Superpave-4 and Superpave-5 mixes to recommend needed modifications of the asphalt mixes that will experience less environmentally driven distresses when used in cold climatic regions.
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    Pavement Rehabilitation Selection
    (Minnesota Department of Transportation, 2008-01) Dai, Shongtao; Skok, Eugene; Westover, Thomas; Labuz, Joseph; Lukanen, Erland
    The objective of the project was to outline best practices for the selection of asphalt pavement recycling techniques from the many choices that are available. The report specifically examines cold-in-place recycling (CIR), plain full depth reclamation (FDR), and mill & overlay (M&O). Interviews, surveys, and site visits were conducted at both Mn/DOT districts and counties, where relevant rehabilitation information was supplied on over 120 projects. A database was constructed to organize the details of these projects, and the parameters in the database included (1) cracking, (2) ride, (3) rutting, (4) age, and (5) traffic volume. From studying the existing rehabilitation projects in the State, Ride Quality Index (RQI) and Surface Rating (SR) were selected as the descriptors of pavement surface condition. A decision procedure based on the analysis of all available projects was developed. The decision procedure included (1) consideration of road geometrics; (2) pavement condition survey; and (3) structural adequacy evaluation. Furthermore, a step-by-step checklist was developed to provide local engineers with a simple and useful tool to follow the decision procedures. The procedure includes selection of rehabilitation method, pavement thickness design, materials mixture design, and construction.
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    Research Shows Benefits of Pavement Preservation Techniques
    (Transportation Engineering and Road Research Alliance (TERRA), 2014-01) Transportation Engineering and Road Research Alliance (TERRA)
    This 2-page fact sheet provides summaries of selected pavement preservation techniques implemented in a variety of research projects at MnROAD. Techniques include monitoring and distress surveys, microsurfacing, lane-shoulder sealing, asphalt longitudinal joint protection, thin warm-mix asphalt overlay, full-depth concrete joint repairs, partial-depth concrete repairs, diamond grinding, ultra-thin bonded wearing coarse with stabilized full-depth reclamation, and thin bonded concrete overlays of asphalt pavement.
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    Ultrasonic linear array evaluation of concrete pavements
    (2013-06) Hoegh, Kyle Edward
    Nondestructive evaluation is an important tool for assurance of proper construction practices and selection of rehabilitation procedures for civil infrastructure. Improvements in technology for testing of concrete structures, such as the introduction of dry point contact ultrasonic arrays, allow for collection of repeatable and spatially diverse shear wave impulse time-histories. This dissertation deals with development of methods that can be used for quantitative evaluation of concrete pavement structures using ultrasound linear array systems. The synthetic aperture focusing technique was adapted to handle spatially diverse measurement pairs. Kirchoff migration and the Hilbert transform were utilized to correlate high intensity portions of the instantaneous amplitude time history envelopes to the physical location of changes in acoustic impedance of the tested medium. To mitigate the effect of limited aperture, the interpretation methods were generalized to accommodate virtual array systems and implemented to create two- and three-dimensional reconstructions of the subsurface concrete structure. This reconstruction analysis was applied for practical pavement problems such as reinforcement and layer boundary location, as well as stochastic flaw detection. Comprehensive ground truth validation on several full-scale concrete pavements confirmed the high resolution of the analytical tools developed in this dissertation.