Download or read book Review of the New Mechanistic empirical Pavement Design Guide a Material Characterization Perspective written by and published by . This book was released on 2005 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of pavement materials in the three hierarchical design levels of the proposed mechanistic-empirical pavement design (MEPD) guide involves application of the dynamic modulus technique for asphalt concrete and the resilient modulus for unbound materials. This approach, if adequately implemented, is expected to improve the road design processes. The advance design level recommends using actual laboratory test data of the dynamic and resilient modulus determined under simulated environmental and traffic loading conditions. To circumvent the need for conducting the mechanical test in lower design levels, predictive equations and correlations established with physical properties are used to estimate the mechanistic properties needed as input to the design software. This paper examines the simplifications incorporated in the model using results of dynamic and resilient modulus tests performed at the National Research Council Canada (NRC). For the covering abstract of this conference see ITRD number E211426.

Download or read book Asphalt Materials Characterization in Support of Implementation of the Proposed Mechanistic empirical Pavement Design Guide written by and published by . This book was released on 2007 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proposed Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure is an improved methodology for pavement design and evaluation of paving materials. Since this new procedure depends heavily on the characterization of the fundamental engineering properties of paving materials, a thorough material characterization of mixes used in Virginia is needed to use the MEPDG to design new and rehabilitated flexible pavements. The primary objective of this project was to perform a full hot-mix asphalt (HMA) characterization in accordance with the procedure established by the proposed MEPDG to support its implementation in Virginia. This objective was achieved by testing a sample of surface, intermediate, and base mixes. The project examined the dynamic modulus, the main HMA material property required by the MEPDG, as well as creep compliance and tensile strength, which are needed to predict thermal cracking. In addition, resilient modulus tests, which are not required by the MEPDG, were also performed on the different mixes to investigate possible correlations between this test and the dynamic modulus. Loose samples for 11 mixes (4 base, 4 intermediate, and 3 surface mixes) were collected from different plants across Virginia. Representative samples underwent testing for maximum theoretical specific gravity, asphalt content using the ignition oven method, and gradation of the reclaimed aggregate. Specimens for the various tests were then prepared using the Superpave gyratory compactor with a target voids in total mix (VTM) of 7% ± 1% (after coring and/or cutting). The investigation confirmed that the dynamic modulus test is an effective test for determining the mechanical behavior of HMA at different temperatures and loading frequencies. The test results showed that the dynamic modulus is sensitive to the mix constituents (aggregate type, asphalt content, percentage of recycled asphalt pavement, etc.) and that even mixes of the same type (SM-9.5A, IM-19.0A, and BM 25.0) had different measured dynamic modulus values because they had different constituents. The level 2 dynamic modulus prediction equation reasonably estimated the measured dynamic modulus; however, it did not capture some of the differences between the mixes captured by the measured data. Unfortunately, the indirect tension strength and creep tests needed for the low-temperature cracking model did not produce very repeatable results; this could be due to the type of extensometers used for the test. Based on the results of the investigation, it is recommended that the Virginia Department of Transportation use level 1 input data to characterize the dynamic modulus of the HMA for projects of significant impact. The dynamic modulus test is easy to perform and gives a full characterization of the asphalt mixture. Level 2 data (based on the default prediction equation) could be used for smaller projects pending further investigation of the revised prediction equation incorporated in the new MEPDG software/guide. In addition, a sensitivity analysis is recommended to quantify the effect of changing the dynamic modulus on the asphalt pavement design. Since low-temperature cracking is not a widespread problem in Virginia, use of level 2 or 3 indirect tensile creep and strength data is recommended at this stage.

Download or read book Mechanistic empirical Pavement Design Guide written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 2008 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Unbound Materials for Mechanistic Empirical Pavement Design Guide MEPDG written by Jeyakaran Thavathurairaja and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Implementation Plan for the New Mechanistic empirical Pavement Design Guide written by Y. Richard Kim and published by . This book was released on 2007 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Unbound Pavement Materials from Virginia Sources for Use in the New Mechanistic empirical Pavement Design Procedure written by M. Shabbir Hossain and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The implementation of mechanistic-empirical pavement design requires mechanistic characterization of pavement layer materials. The subgrade and base materials are used as unbound, and their characterization for Virginia sources was considered in this study as a supplement to a previous study by the Virginia Transportation Research Council. Resilient modulus tests were performed in accordance with AASHTO T 307 on fine and coarse soils along with base aggregates used in Virginia. The degree of saturation as determined by moisture content and density has shown significant influence on the resilient behavior of these unbound materials. The resilient modulus values, or k-values, are presented as reference for use by the Virginia Department of Transportation (VDOT). The results of other tests were analyzed for correlation with the results of the resilient modulus test to determine their use in estimating resilient modulus values. The results of the triaxial compression test, referred to as the quick shear test in AASHTO T 307, correlated favorably with the resilient modulus. Although the complexity of such a test is similar to that of the resilient modulus test for cohesionless coarse soil and base aggregate, fine cohesive soil can be tested with a simpler triaxial test: the unconfined compression test. In this study, a model was developed to estimate the resilient modulus of fine soil from the initial tangent modulus produced on a stress-strain diagram from an unconfined compression test. The following recommendations are made to VDOT's Materials Division: (1) implement the use of the resilient modulus test for pavement design along with the implementation of the MEPDG; (2) use the universal constitutive model recommended by the MEPDG to generate the k-values needed as input to MEPDG Level 1 design/analysis for resilient modulus calculation; (3) develop a database of resilient modulus values (or k-values), which could be used in MEPDG design/analysis if a reasonable material match were to be found; (4) use the initial tangent modulus from an unconfined compression test to predict the resilient modulus values of fine soils for MEPDG Level 2 input and the 1993 AASHTO design; and (5) continue to collect data for the unconfined compression test and update the prediction model for fine soil in collaboration with the Virginia Transportation Research Council. Implementing these recommendations would support and expedite the implementation efforts under way by VDOT to initiate the statewide use of the MEPDG. The use of the MEPDG is expected to improve VDOT's pavement design capability and should allow VDOT to design pavements with a longer service life and fewer maintenance needs and to predict maintenance and rehabilitation needs more accurately over the life of the pavement.

Download or read book Analysis of the Mechanistic empirical Pavement Design Guide Performance Predictions written by Stacey D. Diefenderfer and published by . This book was released on 2010 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures (MEPDG) is an improved methodology for pavement design and the evaluation of paving materials. The Virginia Department of Transportation (VDOT) is expecting to transition to using the MEPDG methodology in the near future. The purpose of this research was to support this implementation effort. A catalog of mixture properties from 11 asphalt mixtures (3 surface mixtures, 4 intermediate mixtures, and 4 base mixtures) was compiled along with the associated asphalt binder properties to provide input values. The predicted fatigue and rutting distresses were used to evaluate the sensitivity of the MEPDG software to differences in the mixture properties and to assess the future needs for implementation of the MEPDG. Two pavement sections were modeled: one on a primary roadway and one on an interstate roadway. The MEPDG was used with the default calibration factors. Pavement distress data were compiled for the interstate and primary route corresponding to the modeled sections and were compared to the MEPDG-predicted distresses. Predicted distress quantities for fatigue cracking and rutting were compared to the calculated distress model predictive errors to determine if there were significant differences between material property input levels. There were differences between all rutting and fatigue predictions using Level 1, 2, and 3 asphalt material inputs, although not statistically significant. Various combinations of Level 3 inputs showed expected trends in rutting predictions when increased binder grades were used, but the differences were not statistically significant when the calibration model error was considered. Pavement condition data indicated that fatigue distress predictions were approximately comparable to the pavement condition data for the interstate pavement structure, but fatigue was over-predicted for the primary route structure. Fatigue model predictive errors were greater than the distress predictions for all predictions. Based on the findings of this study, further refinement or calibration of the predictive models is necessary before the benefits associated with their use can be realized. A local calibration process should be performed to provide calibration and verification of the predictive models so that they may accurately predict the conditions of Virginia roadways. Until then, implementation using Level 3 inputs is recommended. If the models are modified, additional evaluation will be necessary to determine if the other recommendations of this study are impacted. Further studies should be performed using Level 1 and Level 2 input properties of additional asphalt mixtures to validate the trends seen in the Level 3 input predictions and isolate the effects of binder grade changes on the predicted distresses. Further, additional asphalt mixture and binder properties should be collected to populate fully a catalog for VDOT's future implementation use. The implementation of these recommendations and use of the MEPDG are expected to provide VDOT with a more efficient and effective means for pavement design and analysis. The use of optimal pavement designs will provide economic benefits in terms of initial construction and lifetime maintenance costs.

Download or read book Characterization of Material Properties for Mechanistic empirical Pavement Design in Wyoming written by University of Wyoming. Department of Civil and Architectural Engineering and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Wyoming Department of Transportation (WYDOT) recently transitioned from the empirical AASHTO Design for Design of Pavement Structures to the Mechanistic Empirical Pavement Design Guide (MEPDG) as their standard pavement design procedure. A comprehensive field and laboratory test program was conducted in Wyoming to characterize the properties of unbound soil materials. The field test program included falling weight deflectometer (FWD), dynamic cone penetration (DCP), standard penetration test (SPT), soil sampling and pavement distress survey. The laboratory test program included standard soil classification tests, R-value test, standard Proctor compaction test, and resilient modulus (Mr) test in accordance with a protocol by modifying the AASHTO T-307 procedure. All test data was stored and managed by an electronic WYOming MEPDG Database (WYOMEP). Using the FWD data, in-place resilient modulus (MR) of each pavement layer was back-calculated using MODCOMP6 and EVERCALC. For MEPDD Level 2 input, correlation studies were performed to adjust back-calculated modulus to laboratory-derived modulus, calibrate constitutive models, develop relationships between resilient modulus and other soil properties, and develop Mr design tables. Furthermore, tables of unbound soil properties were established for MEPDG Level 3 input. Finally, seven pavement designs were evaluated and compared to achieve the target threshold values and reliability level. The design comparisons and resulting outcomes or predicted distresses for a range of new pavement and rehabilitation designs were presented. The outcomes of these trial examples were used to provide revisions to the 2012 WYDOT MEPDG User Guide.

Download or read book Case Study written by Elias Habib and published by . This book was released on 2016 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Guide for the Local Calibration of the Mechanistic empirical Pavement Design Guide written by and published by AASHTO. This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guide provides guidance to calibrate the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to local conditions, policies, and materials. It provides the highway community with a state-of-the-practice tool for the design of new and rehabilitated pavement structures, based on mechanistic-empirical (M-E) principles. The design procedure calculates pavement responses (stresses, strains, and deflections) and uses those responses to compute incremental damage over time. The procedure empirically relates the cumulative damage to observed pavement distresses.

Download or read book Local Calibration of Material Characterization Models for Performance based Flexible Pavement Design written by Alexander Afuberoh and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mechanistic Empirical Pavement Design Guide (MEPDG) method, currently known as Pavement ME, recommends using locally calibrated material characterization models developed from laboratory testing of local materials under specific environmental and traffic loading conditions. The Pavement ME design method offers a more realistic design procedure and reduces the uncertainty that arise from empirical design procedures. This thesis developed a locally calibrated indirect tensile (IDT) strength material model for low temperature cracking predictions of hot mix asphalt (HMA) in Manitoba, Canada. In addition, the research investigated the integration of locally calibrated HMA, and unbound granular material characterization models into the Pavement ME framework to improve the design of flexible pavements. Laboratory IDT testing was conducted on typical HMA mixtures containing extracted binders and varying percentages of reclaimed asphalt pavement (RAP). The laboratory measured IDT strengths were used to calibrate a local IDT strength predictive model for Manitoba. The predictions from the local Manitoba model were compared to the predictions from the global Pavement ME IDT model, and a Michigan calibrated IDT model, using a statistical analysis. It was found that the global Pavement ME IDT strength model, if used without local calibration, produced inaccurate predictions of the IDT strength for Manitoba mixtures. It was also found that binder characterization methods in Level 2 and Level 3 can significantly impact the accuracy of IDT strength predictions. A case study using developed local HMA, base, and subgrade material characterization models in Manitoba were compared to designs using default (Level 3) material input values in Pavement ME design software. The results of integrating the locally calibrated models for HMA, base and subgrade layers demonstrated that the locally calibrated materials model inputs produce lower pavement structural thicknesses with higher reliability in the predicted distresses when compared to the default materials inputs. The effect of using calibrated material inputs was more pronounced for higher traffic loadings. The results of the study demonstrate that the use of calibrated models can potentially produce optimized pavement thicknesses due to improved pavement designs.

Download or read book Extension of Stress based Finite Element Model Using Resilient Modulus Material Characterization to Develop a Theoretical Framework for Realistic Response Modeling of Flexible Pavements on Cohesive Subgrades written by Kadri Parris and published by . This book was released on 2015 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Pavement design methodologies have over the past decades seen philosophical evolutions and eventually practical implementation of new postulates. As more contributions are made by pavement researchers to the State-of-the-Art in pavement design, there exist a chasm between pavement engineers and state-of-the-art pavement research in terms of incorporation into pavement design guidelines. In developing countries such as Guyana in South America, as well as several departments of transportation, municipalities and townships in the United States, pavement engineers still use the American Association of State Highway and Transportation Officials (AASHTO) Pavement Design Guide (1993). This empirical pavement design guide and its previous iterations were based primarily on data that was collected and processed from the then American Association of State Highway Officials (AASHO) Road Test conducted between 1958 and 1960. The limitations with continued use of this method are obvious since the data was gathered under specific environmental conditions, a specific subgrade type, and with specific materials as well as specific pavement cross-sections. The continued use of this guide does not account for advances in material technology, different types and volumes of vehicular traffic, changing climatic conditions and also can be costly in expanding road networks. To solve this dilemma pavement researchers started working toward a more mechanistic approach for design and through the work of National Cooperative Highway Research Program (NCHRP), culminated in the publishing of the Mechanistic-Empirical Pavement Design Guide (MEPDG) in 2004. The finite element model used in the MEPDG is premised upon a displacement based theory. These theories are capable of making good predictions regarding global responses such as displacements and sometimes in-plane stresses but not the transverse stress distribution. To predict transverse stress distribution, stress based theories are more suitable for use in formulations. At The Ohio State University, Chyou (1989), Schoeppner (1991) and Butalia (1996) worked on different versions of the stress based model for composite laminates. This model was initially extended by Tu (2007) to good effect for analyzing the responses in pavement systems. In this research effort, this response model is being further extended to incorporate a material characterization model into the stiffness matrix for more accurate structural response predictions. The material characterization model (Kim 2004) allows the pavement designer to make predictions of Resilient Modulus, Mr, for cohesive subgrades without the need for conducting the test which can be both costly and complex. This approach renders a cost effective way of obtaining one of the most important parameters for employing a mechanistic approach which is also a major prohibition for many developing countries to move closer to the State-of-the-Art. This new synthesis allows for good predictions of global responses as well as transverse stress distribution which is critical for overcoming pavement layer debonding that can reduce pavement life significantly. Considering the results of the analysis compared to ABAQUS 3D Finite Element Models, this new synthesis forms the basis of a good pavement response model which can be used to further a more mechanistic approach for relatively small design agencies.

Download or read book Nchrp Synthesis 401 written by and published by Transportation Research Board. This book was released on with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Independent Review of the Mechanistic empirical Pavement Design Guide and Software written by Transportation Research Board. National Cooperative Highway Research Program and published by . This book was released on 2006 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Asphalt Material Design Inputs for Use with the Mechanistic empirical Pavement Design Guide in Virginia written by Alex K. Apeagyei and published by . This book was released on 2011 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Guide for the Mechanistic-Empirical Design of New & Rehabilitated Pavement Structures (MEPDG), developed under NCHRP Project 1-37A and recently adopted by the American Association of State Highway and Transportation Officials (AASHTO), offers an improved methodology for pavement design and evaluation. To achieve this improved prediction capability, the MEPDG procedure requires fundamental material properties in addition to certain empirically determined binder and mixture properties as design inputs. One of the key tasks identified by the Virginia Department of Transportation's (VDOT) Asphalt Concrete MEPDG Committee was the laboratory characterization of asphalt mixtures commonly used in Virginia to generate a catalog of the MEPDG-required design inputs. The purpose of this study was to evaluate, compile, and present asphalt material properties in a format that could be readily used in the MEPDG software and to develop a comprehensive catalog of MEPDG design input parameters for pavement design in Virginia. To achieve this objective, 18 asphalt concrete mixtures, sampled from seven of the nine VDOT districts, were tested using a battery of MEPDG-required tests including dynamic modulus (E*), flow number (FN), creep compliance, tensile strength, and beam fatigue tests. Testing involving binder and volumetric properties of the mixtures was also conducted. Finally, rut tests using the asphalt pavement analyzer (APA), a standard VDOT test protocol, were conducted to enable a direct comparison of the APA and FN test results. On the basis of these tests, suggestions for additional studies were made. The results of the study were presented in a form matching the MEPDG input format, and a catalog of design input parameters was developed for the 18 asphalt concrete mixtures. Included in the catalog were binder stiffness, mixture E*, mixture gradation, and mixture volumetric properties that would enable a designer the flexibility to select the desired input level (1, 2, or 3) depending on the pavement type. An illustrative example of how the developed inputs could be implemented using the MEPDG software was also provided. The results showed that E* master curves of asphalt mixtures obtained using the five standard testing temperatures described in AASHTO TP 62 could be obtained by testing at only three temperatures, which could result in a substantial reduction of testing time. The results also showed that the FN test was a sensitive test for evaluating rutting susceptibility of asphalt mixtures in the laboratory. The FN test was found to be sensitive to binder stiffness, mixture stiffness, mixture volumetric properties, aggregate gradation, and amount of recycled asphalt pavement (RAP) for the mixtures considered in this study. The study recommends that the catalog of input data for typical asphalt mixtures developed in this study be considered for pavement design in Virginia. The data followed expected trends and compared quite well with those reported in previous studies. Further studies should be conducted to evaluate the FN test as an additional tool for evaluating rutting in asphalt mixtures. Mixtures containing higher amounts of RAP (>20%) exhibited comparatively lower rutting resistance than those with 20% or less RAP. This phenomenon was unexpected since it is generally believed that adding more RAP should result in stiffer and hence more rut-resistant mixtures. Additional research should be conducted to investigate this phenomenon further.

Download or read book AASHTO Guide for Design of Pavement Structures 1993 written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 1993 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design related project level pavement management - Economic evaluation of alternative pavement design strategies - Reliability / - Pavement design procedures for new construction or reconstruction : Design requirements - Highway pavement structural design - Low-volume road design / - Pavement design procedures for rehabilitation of existing pavements : Rehabilitation concepts - Guides for field data collection - Rehabilitation methods other than overlay - Rehabilitation methods with overlays / - Mechanistic-empirical design procedures.

Download or read book Sensitivity Analysis of and Strategic Plan Development for the Implementation of the M E Design Guide in Texas Department of Transportation Operations written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this project, researchers conducted an extensive sensitivity analysis of the new Mechanistic-Empirical Pavement Design Guide, the development of default input files, and a review of current procedures to develop an implementation strategy and justification of the new pavement design guide. The sensitivity analysis was conducted for the primary design modules, for each level of input data (e.g., Level 1, 2, and 3). The objective of the sensitivity analysis was to determine to what degree the input parameters affect the performance of the initial design. In addition to the sensitivity analysis, the Texas Department of Transportation's (TxDOT's) current pavement design approach was reviewed and contrasted to the design guide to determine what additional tests or other changes will be needed for the implementation of the new design guide. Initial input materials parameters and regional calibration values were developed using available materials information and pavement performance data in TxDOT and research projects.