WorldWideScience

Sample records for design pavement failure

  1. Study on Flexible Pavement Failures in Soft Soil Tropical Regions

    Science.gov (United States)

    Jayakumar, M.; Chee Soon, Lee

    2015-04-01

    Road network system experienced rapid upgrowth since ages ago and it started developing in Malaysia during the colonization of British due to its significant impacts in transportation field. Flexible pavement, the major road network in Malaysia, has been deteriorating by various types of distresses which cause descending serviceability of the pavement structure. This paper discusses the pavement condition assessment carried out in Sarawak and Sabah, Malaysia to have design solutions for flexible pavement failures. Field tests were conducted to examine the subgrade strength of existing roads in Sarawak at various failure locations, to assess the impact of subgrade strength on pavement failures. Research outcomes from field condition assessment and subgrade testing showed that the critical causes of pavement failures are inadequate design and maintenance of drainage system and shoulder cross fall, along with inadequate pavement thickness provided by may be assuming the conservative value of soil strength at optimum moisture content, whereas the exiting and expected subgrade strengths at equilibrium moisture content are far below. Our further research shows that stabilized existing recycled asphalt and base materials to use as a sub-base along with bitumen stabilized open graded base in the pavement composition may be a viable solution for pavement failures.

  2. Agency and Design: Pavement Failure in the Transmilenio Project, Bogotá, Colombia

    DEFF Research Database (Denmark)

    Pineda, Andres Felipe Valderrama

    paper is a post mortem analysis of the failure of the slabs in Bogotá. The main interest in this case is to devise the ways in which design decisions are taken and performed in a complex relation of actors among city authorities, academic experts, design consultants, inspectors and users. STS literature...

  3. Relationship between road pavement failures, engineering indices ...

    African Journals Online (AJOL)

    This article presents the results of a study carried out to relate the frequency of pavement failures, the engineering indices of the subgrade materials and the underlying geology. The results show a high variability in the indices such as the liquid limit, LL, the plasticity index, PI, the maximum dry density, MDD, the optimum ...

  4. Toward using tire-road contact stresses in pavement design and analysis

    CSIR Research Space (South Africa)

    De Beer, Morris

    2012-10-01

    Full Text Available Optimization of road pavement design, especially towards the surface of the pavement, requires a more rational approach to modeling of truck tire-road contact stresses. Various road surfacing failures are given in this paper as examples...

  5. Towards using tire-road contact stresses in pavement design and analysis

    CSIR Research Space (South Africa)

    De Beer, Morris

    2011-09-01

    Full Text Available Optimization of road pavement design, especially towards the surface of the pavement, requires a more rational approach to modeling of truck tire-road contact stresses. Various road surfacing failures are given in this paper as examples...

  6. Highway pavement failure induced by poor soil geotechnical ...

    African Journals Online (AJOL)

    X-ray diffraction studies showed the presence of abundant kaolinite peaks and a subdued goethite peak without any trace of montmorrilonite. The presence of excess fines in the pavement construction materials (soils) contributed to the failure of the highway pavement at this locality. The low CBR value is also a noted cause ...

  7. Forensic analysis of asphaltic pavement failures in Ghana: case histories

    CSIR Research Space (South Africa)

    Ampadu, SIK

    2015-08-01

    Full Text Available Many newly constructed asphaltic pavements in Ghana have suffered premature failures shortly after opening to traffic. In all cases, available records from the road agencies appeared to show that the roads were constructed in accordance...

  8. Mechanistic flexible pavement overlay design program.

    Science.gov (United States)

    2009-07-01

    The current Louisiana Department of Transportation and Development (LADOTD) overlay thickness design method follows the Component : Analysis procedure provided in the 1993 AASHTO pavement design guide. Since neither field nor laboratory tests a...

  9. Fracture mechanics in pavement design

    CSIR Research Space (South Africa)

    Denneman, E

    2009-07-01

    Full Text Available MODELLING FRACTURE IN PAVEMENT MATERIALS The cohesive crack approach can be incorporated in finite element method (FEM) to simulate fracture in pavement materials. In this paper an embedded discontinuity method (EDM) based on the work by Sancho et al... through elements, in other words, independent of nodal positions and element boundaries. The EDM was used for the numerical simulation of two examples of fracture tests on road materials from the literature. The model is applied to reproduce...

  10. Precision and accuracy of mechanistic-empirical pavement design

    CSIR Research Space (South Africa)

    Theyse, HL

    2006-09-01

    Full Text Available The availability of mechanistic-empirical pavement design methods is increasing internationally. Although mechanistic-empirical design does offer some insight into pavement behaviour and performance, at least more so than empirical design methods...

  11. Mechanistic flexible pavement overlay design program : tech summary.

    Science.gov (United States)

    2009-07-01

    The Louisiana Department of Transportation and Development (LADOTD) currently follows the 1993 : AASHTO pavement design guides component analysis method in its fl exible pavement overlay thickness : design. Such an overlay design method, how...

  12. AASHTO mechanistic-empirical pavement design guide parametric study.

    Science.gov (United States)

    2012-03-01

    This study focuses on assessing the robustness of the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG v 1.1) for rigid pavement : design projects in Wisconsin. The primary tasks conducted in this study included performing sensitivity analys...

  13. Development of New Bituminous Pavement Design Method

    DEFF Research Database (Denmark)

    Ullidtz, Per

    The report and work of COST Action 333 sets in place the foundation for a coherent, cost-effective and harmonised European pavement design method. In order to do this, the work programme focused on information gathering, identification of requirements and the selection of the necessary design...

  14. Overlay design method based on visual pavement distress.

    Science.gov (United States)

    1978-01-01

    A method for designing the thickness of overlays for bituminous concrete pavements in Virginia is described. In this method the thickness is calculated by rating the amount and severity of observed pavement distress and determining the total accumula...

  15. Overview of the South African mechanistic pavement design analysis method

    CSIR Research Space (South Africa)

    Theyse, HL

    1996-01-01

    Full Text Available A historical overview of the South African mechanistic pavement design method, from its development in the early 1970s to the present, is presented. Material characterization, structural analysis, and pavement life prediction are discussed...

  16. Future design of perpetual pavements for New Mexico.

    Science.gov (United States)

    2009-12-29

    This study provides guidance for future designs of perpetual pavements in New Mexico. The perpetual pavement in this study refers to only hot mix asphalt (HMA) pavement sections designed for a useful life of 50 years or more without having major dist...

  17. Texas perpetual pavements : new design guidelines.

    Science.gov (United States)

    2010-06-01

    Since 2001, the State of Texas has been designing and constructing perpetual pavements : on some of its heavily trafficked highways where the expected 20-year truck-traffic estimate of : 18 kip ESALs is in excess of 30 million (TxDOT, 2001). To date,...

  18. Design and construction of PCC pavements. Volume 2, design features and practices that influence performance of pavements

    Science.gov (United States)

    1998-10-01

    A study has been conducted to evaluate and analyze Portland cement concrete (PCC) pavements in order to develop recommendations for the design and construction of long-lived concrete pavements. In involved a detailed evaluation and analysis of the PC...

  19. Design and construction of PCC pavements, volume 2 : design features and practices that influence performance of pavements.

    Science.gov (United States)

    1998-10-01

    A study has been conducted to evaluate and analyze portland cement concrete (PCC) pavements in order to : develop recommendations for the design and construction of long-lived concrete pavements. It involved a : detailed evaluation and analysis of th...

  20. Design and construction of PCC pavements. Volume 1, summary of design features and construction practices that influence performance of pavements

    Science.gov (United States)

    1998-04-01

    A study has been conducted to evaluate and analyze Portland cement concrete (PCC) pavements in order to develop recommendations for the design and construction of long-lived concrete pavements. In involved a detailed evaluation and analysis of the PC...

  1. Determination of coefficient of thermal expansion effects on Louisiana's PCC pavement design.

    Science.gov (United States)

    2011-12-01

    With the development of the Mechanistic Empirical Pavement Design Guide (MEPDG) as a new pavement design tool, the : coefficient of thermal expansion (CTE) is now considered a more important design parameter in estimating pavement : performance inclu...

  2. Evaluation of current Louisiana flexible pavement structures using PMS data and new mechanistic-empirical pavement design guide : tech summary.

    Science.gov (United States)

    2012-04-01

    The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Cooperative Highway : Research Program (NCHRP) Project 1-37A represents a major change as compared to the 1993 AASHTO Pavement : Design Guide. MEPDG provides a r...

  3. Airport Pavement Design For The Boeing 777 Airplane

    Science.gov (United States)

    1995-10-22

    The purpose of this advisory circular is to provide thickness design standards : for pavements intended to serve the Boeing 777 airplane. A new method of design : based on layered elastic analysis has been developed to calculate design : thickness fo...

  4. Inclusion of LCCA in Alaska flexible pavement design software manual.

    Science.gov (United States)

    2012-10-01

    Life cycle cost analysis is a key part for selecting materials and techniques that optimize the service life of a pavement in terms of cost and performance. While the Alaska : Flexible Pavement Design software has been in use since 2004, there is no ...

  5. Application of WIM to pavement design. Effect of WIM accuracy

    Directory of Open Access Journals (Sweden)

    J. Leal Bermejo

    2017-03-01

    Full Text Available Weigh-in-motion (WIM techniques can provide data on vehicle and axle weights when they are travelling at full highway speeds. In this paper, the application of WIM data to the design of road pavements is described and the effect of WIM load data accuracy on the estimate of pavement service life is analysed. Thus, the main factors affecting WIM accuracy are explained, especially those related to vehicle-pavement interaction. Afterwards, a trial that has been conducted to evaluate the effect of WIM load data accuracy on pavement life prediction will be presented. The results obtained show that the errors in axle load measurements can lead to higher errors in pavement life estimates.

  6. Predictive design procedures, VESYS users manual : an interim design method for flexible pavements using the VESYS structural subsystem

    Science.gov (United States)

    1978-01-01

    This manual has been written to provide the pavement manager and design engineer with a ready reference of procedures to predict the structural responses and hence the integrity of flexible pavements. A pavement section of known geometry is chosen, a...

  7. Rehabilitation design of flexible pavements in South Africa.

    CSIR Research Space (South Africa)

    De Beer

    1997-01-01

    Full Text Available This report contains a set of practical course notes on the Rehabilitation Design of flexible pavements in southern Africa based on extensive research by various researchers and / or practitioners in South Africa. The course is intended...

  8. Pavement subgrade MR design values for Michigan's seasonal changes : appendices.

    Science.gov (United States)

    2009-07-22

    The resilient modulus (MR) of roadbed soil plays an integral role in the design of pavement systems. Currently, the various regions of the Michigan Department of Transportation (MDOT) use different procedures to determine the MR values. Most of these...

  9. Revision of South African pavement design method

    CSIR Research Space (South Africa)

    Kannemeyer, L

    2015-08-01

    Full Text Available South Africa has a long pavement engineering history in terms of developing methodologies and solutions for supporting the local economy using available materials under specific environmental and socio-economic conditions. Over the past 10 years...

  10. A User Friendly Software for Rigid Pavement Design

    Directory of Open Access Journals (Sweden)

    Aydın Kıcı

    2017-12-01

    Full Text Available Concrete pavements as concrete road slab, appear as a strong alternative for flexible superstructures especially because of their low cost for maintenance and repair and the high performance they show under heavy axle loads. The design of these concrete road slabs is quite different from the traditional concrete and reinforced concrete structures’ design. In the design for this kind of pavements, traffic conditions should be defined properly and considered an addition to the concrete and platform properties. There have been designing methods developed based on both experimental and mechanic foundations for concrete pavements. The most important ones of these methods are AASHTO (1993 and PCA (1984. In both design methods, it’s significant to know the maximum deflections and maximum strains the vehicles’ loads cause on the pavement. The calculation of this maximum deflections and maximum strains can be done via the finite element method or the closed formulas which have been developed by Westergaard. In this study, a user-friendly software has been developed based on AASHTO 1993, PCA 1984 design methods and Westergaard formulas. Thanks to this software, the user who wants to design the concrete pavement as concrete road slab can obtain the essential parameters automatically by entering the required data for the design.

  11. Evaluation of current Louisiana flexible pavement structures using PMS data and new mechanistic-empirical pavement design guide.

    Science.gov (United States)

    2012-04-01

    The new Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under the National Cooperative Highway Research Program (NCHRP) Project 1-37A represents a major change as compared to the 1993 AASHTO Pavement Design Guide. The MEPDG provides a r...

  12. Laboratory data to determine impact of coarse aggregate type and cementitious materials on design thickness of PCC pavements.

    Science.gov (United States)

    2016-12-01

    The Mississippi Department of Transportation (MDOT) needed mechanical and volume change properties of portland cement concrete (PCC) pavement in order to implement pavement thickness design procedures of the Mechanistic-Empirical Pavement Design Guid...

  13. Mechanistic-empirical design concepts for continuously reinforced concrete pavements in Illinois.

    Science.gov (United States)

    2009-04-01

    The Illinois Department of Transportation (IDOT) currently has an existing jointed plain concrete pavement : (JPCP) design based on mechanistic-empirical (M-E) principles. However, their continuously reinforced concrete : pavement (CRCP) design proce...

  14. Flexible and composite structures for premium pavements. Volume 2, Design manual

    Science.gov (United States)

    1980-11-01

    This design manual presents the results of a detailed study to identify and design flexible and composite pavement configurations which will perform as premium or "zero-maintenance" pavements. This manual includes identification and classification of...

  15. Engineering properties of stabilized subgrade soils for implementation of the AASHTO 2002 pavement design guide.

    Science.gov (United States)

    2009-06-01

    A comprehensive laboratory study was undertaken to determine engineering properties of cementitiously stabilized common subgrade soils in Oklahoma for the design of roadway pavements in accordance with the AASHTO 2002 Mechanistic-Empirical Pavement D...

  16. Determination of coefficient of thermal expansion effects on Louisiana's PCC pavement design : technical summary report.

    Science.gov (United States)

    2011-12-01

    The coefficient of thermal expansion (CTE) has been widely considered as a fundamental property of : Portland cement concrete (PCC) pavement but has never played an important role in the thickness design : procedure for PCC pavement until recently. I...

  17. Forensic Investigation of Premature Failure of a Roadway Pavement ...

    African Journals Online (AJOL)

    Tests conducted on the pavement layers of the failed road included moisture content, particle size distribution of soil samples, Atterberg limit tests, in-situ density and dynamic cone penetrometer (DCP) tests. An empirical equation from published literature was used to compute the California bearing ratio (CBR) of various ...

  18. Investigation of causes of failures of flexible pavements: a case ...

    African Journals Online (AJOL)

    The visual inspection of the pavement showed that due to the hardening of the bitumen and overloading, cracks and potholes were very common for the whole stretch of the road. Axle load data revealed that, there has been a tendency to exceed the maximum allowed axle load limits, especially until 19th august, 1999, after ...

  19. ANALYSES OF THE INFLUENCE OF MATERIAL CHARACTERISTICS ON PAVEMENT DESIGN

    Directory of Open Access Journals (Sweden)

    Nino Vukobratović

    2017-01-01

    Full Text Available Currently, only empirical design methods are used in the application of well-known standards for pavement structure design. Given this fact, it is assumed that material characteristics correspond to average quality materials. Thus, the aim of this study included examining the influence of material characteristics on pavement design analyzing changes in the cement bound base layer (CBL characteristics with respect to the occurrence of cracks and changes in the asphalt layer given typical seasonal changes. The study involved varying CBL modulus as 15 GPa, 10 GPa, and 5 GPa. Additionally, the moduli of asphalt layers were varied from 6 MPa to 2 MPa to simulate real conditions in pavement structure life. The analyses indicated that there was a significant difference in pavement behavior with respect to changes in material characteristics. Given these significant differences, it is extremely important to properly define material characteristics while using empirical design methods. Proper material characterization combined with the utilization of empirical and analytical methods increases the possibility of reducing layers thickness to design cost-effective structures.

  20. Road Materials and Pavement Design, volume 18, issue 1

    CSIR Research Space (South Africa)

    De Beer, Morris

    2017-01-01

    Full Text Available and Pavement Design Volume 18, 2017 - Issue 1 Editorial Board Page ebi | Published online: 03 Oct 2016 http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France Andrew Charles...

  1. Road Materials and Pavement Design, volume 18, issue 2

    CSIR Research Space (South Africa)

    De Beer, Morris

    2017-03-01

    Full Text Available and Pavement Design Volume 18, 2017 - Issue 2 Editorial Board Page ebi | Published online: 03 Oct 2016 http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France Andrew Charles...

  2. Fatigue and rutting strain analysis of flexible pavements designed ...

    African Journals Online (AJOL)

    The layered elastic analysis of pavements designed using three known CBR methods; the Asphalt Institute, the National Crushed Stone Association and the Nigerian CBR methods were carried out to evaluate their fatigue strain and rutting deformation characteristics. The elastic properties of the materials were determined.

  3. Road Materials and Pavement Design, 30 May 2017

    CSIR Research Space (South Africa)

    De Beer, Morris

    2017-01-01

    Full Text Available and Pavement Design Vol. 18, Issue 1 2017 http://www.tandfonline.com/toc/trmp20/18/1?nav=tocList Editorial board EDITORS-IN-CHIEF Hervé Di Benedetto - University of Lyon / ENTPE, Vaulx-en-Velin, France Andrew Charles Collop - De Montfort University...

  4. Appraisal of the Causes of Pavement

    African Journals Online (AJOL)

    INTRODUCTION. Pavement failures are very common features on. Nigeria in roads after few years of performance and often before attaining the design age. These roads are continuously reconstructed or rehabilitated without any effort made to identify factor(s) responsible for their perpetual failure. Pavement failures can ...

  5. Appraisal of the causes of pavement failure along the Ilesa - Akure ...

    African Journals Online (AJOL)

    Remotely sensed and geotechnical data have been used to establish some of the causes of perpetual pavement failure along the Ilesa Akure highway in the southwestern part of Nigeria. Four failed segments and two control stable segments were selected for the geotechnical study. The remote sensing investigation ...

  6. Advanced Pavement Design: Finite Element Modeling for Rigid Pavement Joints, Report II: Model Development

    National Research Council Canada - National Science Library

    Hammons, Michael

    1998-01-01

    .... The objective of this research was to obtain data on the response of the ng'id pavement slab-joint-foundation system by conducting laboratory-scale experiments on jointed rigid pavement models...

  7. Vehicle classes for pavement design and capacity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kubala, J.; Asce, M.; Lalani, N.; O' Connell, R.; Petersen, C.

    1986-11-01

    Transportation engineers working in Colorado were aware of a lack of published data at both the local and national level for vehicle classes on urban streets. Such vehicle class breakdowns are necessary for calculating equivalent daily loaded axle (EDLA) values for pavement design and conducting capacity analyses. A technical committee was formed to collect and analyze weekday vehicle class data on urban streets of various types. The major vehicle classes are passenger cars (70-75%), pickups (15-20%), single unit trucks (5-7%); tractor-trailers, buses, and recreational vehicles account for less than 1%. Using these data, a microcomputer spread sheet was set up to calculate EDLA values for pavement design for a range of design year volumes. This vehicle class data is also very useful in highway capacity calculations.

  8. Design Basis for Fibre Reinforced Concrete (FRC) Pavements

    DEFF Research Database (Denmark)

    Bendixen, Søren; Stang, Henrik

    1996-01-01

    opening relationship can beused to descibe the properties of fibre reinforced concrete (FRC) intension and how the stress-crack opening relationship can beapplied in a simple design scheme for pavements. The projectincludes development of design tools, experiments to determine thestress-crack opening......The paper summarises a Ph.D. project on development of a new design basis for fibre reinforced concrete ground slabs. The stress-crack openingrelationship is a well know basic material property of theso-called fictitious crack model for concrete. In the presentstudy it is shown how the stress-crack...

  9. Accelerated testing for studying pavement design and performance (FY 2004) : research summary.

    Science.gov (United States)

    2009-03-01

    The thirteenth full-scale Accelerated Pavement Test (APT) experiment at the Civil Infrastructure Laboratory (CISL) of Kansas State University aimed to determine the response and the failure mode of thin concrete overlays.

  10. Road Materials and Pavement Design volume 17(4).

    CSIR Research Space (South Africa)

    De Beer, Morris

    2016-03-01

    Full Text Available Materials and Pavement Design Volume 17, 2016 - Issue 4 Editorial Board Page ebi | Published online: 03 Oct 2016  http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France... Andrew Charles COLLOP - De Montfort University, Leicester, UK William G. BUTTLAR - University of Missouri, Urbana-Champaign, USA Editor-in-Chief at Large Jorge B. Sousa - Consulpav, Oeiras, Portugal Associate Editors Morris de Beer - CSIR Built...

  11. Road Materials and Pavement Design volume 17(2)

    CSIR Research Space (South Africa)

    De Beer, Morris

    2016-03-01

    Full Text Available Materials and Pavement Design Volume 17, 2016 - Issue 2 Editorial Board Page ebi | Published online: 03 Oct 2016  http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France... Andrew Charles COLLOP - De Montfort University, Leicester, UK William G. BUTTLAR - University of Missouri, Urbana-Champaign, USA Editor-in-Chief at Large Jorge B. Sousa - Consulpav, Oeiras, Portugal Associate Editors Morris de Beer - CSIR Built...

  12. Road Materials and Pavement Design Volume 17(1)

    CSIR Research Space (South Africa)

    De Beer, Morris

    2016-03-01

    Full Text Available Materials and Pavement Design Volume 17, 2016 - Issue 1 Editorial Board Page ebi | Published online: 03 Oct 2016  http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France... Andrew Charles COLLOP - De Montfort University, Leicester, UK William G. BUTTLAR - University of Missouri, Urbana-Champaign, USA Editor-in-Chief at Large Jorge B. Sousa - Consulpav, Oeiras, Portugal Associate Editors Morris de Beer - CSIR Built...

  13. Road Materials and Pavement Design, Volume 17(3)

    CSIR Research Space (South Africa)

    De Beer, Morris

    2016-03-01

    Full Text Available Materials and Pavement Design Volume 17, 2016 - Issue 3 Editorial Board Page ebi | Published online: 03 Oct 2016  http://dx.doi.org/10.1080/14680629.2016.1244475 Editors-in-Chief Hervé DI BENEDETTO - University of Lyon/ENTPE, Vaulx-en-Velin, France... Andrew Charles COLLOP - De Montfort University, Leicester, UK William G. BUTTLAR - University of Missouri, Urbana-Champaign, USA Editor-in-Chief at Large Jorge B. Sousa - Consulpav, Oeiras, Portugal Associate Editors Morris de Beer - CSIR Built...

  14. Interim revision of the South African Mechanistic-Empirical pavement design method for flexible pavements

    CSIR Research Space (South Africa)

    Theyse, HL

    2011-09-01

    Full Text Available an interim revision of the SAMDM recommending increased contact stress values at the tyre-pavement interface; updated unbound material characterisation parameters; effective stress analysis for unbound material; and revised damage models for estimating...

  15. Mechanistic-Empirical Pavement Design Guide Flexible Pavement Performance Prediction Models Volume I Executive Research Summary

    Science.gov (United States)

    2007-08-01

    The objective of this research study was to develop performance characteristics or variables (e.g., ride quality, rutting, : fatigue cracking, transverse cracking) of flexible pavements in Montana, and to use these characteristics in the : implementa...

  16. Mechanistic-Empirical Pavement Design Guide Flexible Pavement Performance Prediction Models Volume II Reference Manual

    Science.gov (United States)

    2007-08-01

    The objective of this research study was to develop performance characteristics or variables (e.g., ride quality, rutting, : fatigue cracking, transverse cracking) of flexible pavements in Montana, and to use these characteristics in the : implementa...

  17. Evaluation of the fatigue and toughness of fiber reinforced concrete for use as a new highway pavement design.

    Science.gov (United States)

    2016-04-01

    Concrete pavement design is currently centered on steel reinforcement, whether that reinforcement be in the : form of dowel bars, as is the case in jointed plain concrete pavement (JPCP), or in the form of continuous rebar : reinforcement, continuous...

  18. Incorporating moving dynamic tyre loads in pavement design and analysis

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2000-07-01

    Full Text Available at the University of Pretoria. 4 REAL LIFE TYRE LOADS Characterisation Pavement loading has been shown by various authors to be a dynamic (time-dependent) phenomenon (Divine, 1997; Cebon, 1999). A pavement experiences a vehicle as a moving, time-varying set... is that caused by the pavement roughness-induced movement of the vehicle. This is traditionally termed dynamic pavement loading (Divine, 1997). Tyre load definitions Four types of tyre loading can be identified: 1. A load that is independent of time...

  19. Design of the First Italian Roundabout with Jointed Plain Concrete Pavement

    Directory of Open Access Journals (Sweden)

    Paola Di Mascio

    2018-02-01

    Full Text Available This work presents the results of the overall design of the first Italian roundabout with jointed plain concrete pavement. The examined case study complies with current international standards and practices for geometry of roundabouts and road pavements. The construction of a concrete pavement in an urban roundabout will better manage and slow down fast vehicular flows, and increase traffic fluidity in an important junction, trafficked by heavy vehicles, where maintenance works should be reduced to avoid queues. The design of the roundabout involved several competences for: defining the geometry of the four-arm junction, designing the thickness of the jointed plain concrete pavement both on the circular crown and the arms, studying the mix design of a high resistance concrete. As regard to the pavement, the result of the study was an un-dowelled concrete pavement composed of square slabs laid on a cement concrete subbase and a granular layer. The shape of the slabs has been designed to optimize the structural performance of their material, which is a high strength concrete mix derived from an extensive laboratory test work. In general, the results summarized approaches typical of different design conditions: urban ones for traffic flow and safety needs; high-traffic ones for the chosen pavement type; airport ones for the absence of dowel and tie bars at the joints. Indeed, the article has highlighted that the design process of a concrete roundabout requires multiple analyses to consider various features and correctly re-design an existing urban junction. Its geometrical design, the structural design of the concrete pavement and the theoretical and experimental design of the concrete mix were the main phases of this process and they needed different competences to conduct comprehensive and appropriate analyses.

  20. An Optimization Model for Design of Asphalt Pavements Based on IHAP Code Number 234

    Directory of Open Access Journals (Sweden)

    Ali Reza Ghanizadeh

    2016-01-01

    Full Text Available Pavement construction is one of the most costly parts of transportation infrastructures. Incommensurate design and construction of pavements, in addition to the loss of the initial investment, would impose indirect costs to the road users and reduce road safety. This paper aims to propose an optimization model to determine the optimal configuration as well as the optimum thickness of different pavement layers based on the Iran Highway Asphalt Paving Code Number 234 (IHAP Code 234. After developing the optimization model, the optimum thickness of pavement layers for secondary rural roads, major rural roads, and freeways was determined based on the recommended prices in “Basic Price List for Road, Runway and Railway” of Iran in 2015 and several charts were developed to determine the optimum thickness of pavement layers including asphalt concrete, granular base, and granular subbase with respect to road classification, design traffic, and resilient modulus of subgrade. Design charts confirm that in the current situation (material prices in 2015, application of asphalt treated layer in pavement structure is not cost effective. Also it was shown that, with increasing the strength of subgrade soil, the subbase layer may be removed from the optimum structure of pavement.

  1. Reconsideration of tyre-pavement input parameters for the structural design of flexible pavements

    CSIR Research Space (South Africa)

    De Beer, Morris

    2006-08-01

    Full Text Available which have higher inflation pressures and hence higher contact stresses than was previously the case. The aim of this paper is to highlight the variabilities associated with actual measured three-dimensional tyre-pavement contact loading/stress regimes...

  2. Texas M-E flexible pavement design system: literature review and proposed framework.

    Science.gov (United States)

    2012-04-01

    Recent developments over last several decades have offered an opportunity for more rational and rigorous pavement design procedures. Substantial work has already been completed in Texas, nationally, and internationally, in all aspects of modeling, ma...

  3. Bitumen rubber asphalt mix testing for South African pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2011-07-01

    Full Text Available The South Africa National Road Agency Ltd has entered into a research and laboratory testing agreement with the CSIR to support the revision of the South African Pavement Design Method (SAPDM). The research includes characterising a bitumen...

  4. Material Testing and Initial Pavement Design Modeling: Minnesota Road Research Project

    Science.gov (United States)

    1996-09-01

    Between January 1990 and December 1994, a study verified and applied a Corps of Engineers-developed mechanistic design and evaluation method for pavements in seasonal frost areas as part of a Construction Productivity Advancement Research (CPAR) proj...

  5. Ultra-thin reinforced concrete pavements (UTRCP): Addressing the design issues

    CSIR Research Space (South Africa)

    Du Plessis, L

    2014-07-01

    Full Text Available The design and use of ultra-thin reinforced concrete pavements (UTRCP) are well known and are implemented successfully in residential streets and low-volume roads. Various publications are available to assist engineers and contractors...

  6. Context sensitive design : thinking beyond the pavement : documentation of workshop development and training.

    Science.gov (United States)

    2005-05-01

    This report documents the development and presentation of the workshop titled Thinking Beyond the Pavement A Workshop on Context Sensitive Design. Work began on the workshop development in 1998 after the Kentucky Transportation Cabinet was ...

  7. Short course on: Rehabilitation design of flexible pavements in South Africa

    CSIR Research Space (South Africa)

    De Beer, Morris

    1997-09-01

    Full Text Available This report contains a set of practical course notes on the Rehabilitation Design of flexible pavements in southern Africa based on extensive research by various researchers and / or practitioners in South Africa. The course is intended...

  8. Pavement subgrade MR design values for Michigan's seasonal changes : final report.

    Science.gov (United States)

    2009-07-22

    The resilient modulus (MR) of roadbed soil plays an integral role in the design of pavement systems. Currently, the : various regions of the Michigan Department of Transportation (MDOT) use different procedures to determine the : MR values. Most of t...

  9. Pavement subgrade MR design values for Michigan's seasonal changes : table E4.

    Science.gov (United States)

    2009-07-22

    The resilient modulus (MR) of roadbed soil plays an integral role in the design of pavement systems. Currently, the various regions of the Michigan Department of Transportation (MDOT) use different procedures to determine the MR values. Most of these...

  10. Pavement subgrade MR design values for Michigan's seasonal changes : table E5.

    Science.gov (United States)

    2010-06-22

    The resilient modulus (MR) of roadbed soil plays an integral role in the design of pavement systems. Currently, the various regions of the Michigan Department of Transportation (MDOT) use different procedures to determine the MR values. Most of these...

  11. Permanent deformation testing for a new South African mechanistic pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2012-01-01

    Full Text Available deformation test protocol and models using a standard South African hot-mix asphalt material. The developed test protocol and models provide guidelines, and make a significant contribution to pavement design in South Africa....

  12. Accelerated testing for studying pavement design and performance (FY 2004) : thin bonded rigid overlay on PCCP and HMA (CISL experiment no. 13).

    Science.gov (United States)

    2009-03-01

    The thirteenth full-scale Accelerated Pavement Test (APT) experiment at the Civil Infrastructure Laboratory (CISL) : of Kansas State University aimed to determine the response and the failure mode of thin concrete overlays. Four : pavement structures...

  13. Inverted base pavements : new field test and design catalogue.

    Science.gov (United States)

    2014-01-01

    The current economic situation has severely affected the US road infrastructure and funding has become : inadequate for either maintenance or future growth. : The inverted base pavement structure is a promising alternative to achieve high quality roa...

  14. Road Edge of Pavement, Pavement Condition Ratings and Maintenance Designations per Street Centerline. Updated frequently by Public Works Streets Division, Published in 2006, 1:1200 (1in=100ft) scale, City of Asheville Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Road Edge of Pavement dataset current as of 2006. Pavement Condition Ratings and Maintenance Designations per Street Centerline. Updated frequently by Public Works...

  15. Mechanistic-Empirical Pavement Design Guide Flexible Pavement Performance Prediction Models Volume III Field Guide - Calibration and User's Guide for the Mechanistic-Empirical Pavement Design Guide

    Science.gov (United States)

    2007-08-01

    The objective of this research study was to develop performance characteristics or variables (e.g., ride quality, rutting, : fatigue cracking, transverse cracking) of flexible pavements in Montana, and to use these characteristics in the : implementa...

  16. Urban permeable pavement system design based on “sponge city” concept

    Science.gov (United States)

    Yu, M. M.; Zhu, J. W.; Gao, W. F.; Xu, D. P.; Zhao, M.

    2017-08-01

    Based on the “sponge city” concept, to implement the goal of building a city within the city to solve the sponge waterlogging, rational utilization of water resources, reduce water pollution this paper, combined with the city planning level in China, establishes the design system of city road flooding from the macro, medium and micro level, explore the design method of city water permeable pavement system, and has a practical significance the lower flood risk water ecological problems. On the macro level, we established an urban pavement sponge system under the regional ecological pattern by “spot permeable open space - low impact developing rain water road system - catchment area and catchment wetland”. On a medium level, this paper proposed the permeable suitability of pavement and the planning control indicators when combined with urban functional districts to conduct permeable pavement roads plans and controls. On micro level, the paper studied sponge technology design of permeable pavement from road structure, surface material, and other aspects aimed at the pavement permeability requirements.

  17. Failure by design?

    DEFF Research Database (Denmark)

    Moyo, Francis; Ijumba, Jasper; Lund, Jens Friis

    2016-01-01

    In this paper, we revisit the on-the-ground reality of Burunge Wildlife Management Area (WMA) that is celebrated as one of Tanzania's best examples of community-based conservation (CBC). We find Burunge WMA rife with conflict and contestation over grievances that remained unsettled since its esta...... failure to address this detrimental discrepancy between reality and representation, and start supporting affected residents in their struggles for self-determination....

  18. Greenhouse gas emissions of alternative pavement designs: framework development and illustrative application.

    Science.gov (United States)

    Liu, Xiaoyu; Cui, Qingbin; Schwartz, Charles

    2014-01-01

    Pavement rehabilitation is carbon intensive and the choice of pavement type is a critical factor in controlling greenhouse gas (GHG) emissions. The existing body of knowledge is not able to support decision-making on pavement choice due to a lack of consensus on the system boundaries, the functional units and the estimation periods. Excessive data requirements further inhibit the generalization of the existing methodologies for design evaluation at the early planning stage. This study proposes a practical life-cycle GHG estimation approach, which is arguably effective to benchmark pavement emissions given project bid tabulation. A set of case studies conducted for this study suggest that recycled asphalt pavement (e.g., foam stabilized base (FSB), and warm mix asphalt (WMA)) would prevent up to 50% of GHGs from the initial construction phase. However, from a life-cycle perspective, pavement emissions are dictated largely by the traffic characteristics and the analysis period for the use phase. The benefits from using recycled materials (e.g., FSB) are likely to diminish if the recycled products do not perform as well as those properly proportioned with less recycled materials, or if the recycled materials are locally unavailable. When the AADT reaches 10,000, use phase releases more than 97% of the life cycle emissions and the emissions difference among alternative designs will be within 1%. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Evaluation of current Louisiana flexible pavement structures using PMS data and new M-E pavement design guide.

    Science.gov (United States)

    2010-10-01

    The proposed study uses the new MEPDG together with data available from LADOTDs Pavement Management System (PMS) and other data sources from LADOTDs main frame to evaluate typical flexible pavement structures currently used and to make changes ...

  20. Design prediction of pavement skid resistance from laboratory tests

    Science.gov (United States)

    Parcells, W. H.; Metheny, T. M.; Maag, R. G.

    1980-08-01

    Methods for preevaluating aggregates and paving mixtures so that predictions can be made covering skid resistance properties of proposed and in service pavement types are discussed. A correlation was established between the field testing using the data from the British Portable Tester and the Locked Wheel Pavement Friction Trailer at speeds of 40 and 55 mph. Core samples were extracted from the Locked Wheel Tester Skid Path and subjected to wear on the small wheel circular track with periodic surface friction testing. The final step was to remix and remold the cored pavement samples or make samples with new materials to obtain an 'as new' surface and again subject these samples to wear on the small wheel circular track with periodic testing.

  1. Climatic Characteristics of Slovakia in the Years 1971 to 2011 from the Aspect of Pavement Design

    Science.gov (United States)

    Decky, Martin; Remisova, Eva; Kovalcik, Lubomír; Dibdiakova, Jana; Hajek, Matej

    2017-12-01

    Contribution follows the previous work of authors in the field of implementation of objectified results of climate change in the design of roads, especially their pavement [1] to [3]. Climate conditions are besides traffic load, one of the permanent external factors adversely affecting the physical and mechanical properties of the construction layers. For designing concrete pavements is used in SR conditions average annual air temperature Tm and frost index for design of asphalt and concrete pavements. As part of the research activities carried out at the workplace, the authors statistically evaluated average daily temperatures of SR meteorological stations covering most of the SR territory with altitude from 115 to 695 m above sea level in the years 1971 to 2011. Act No. 135/1961 Coll. (Road Act) states that the design of road pavements is performed according to valid Slovak technical standards, technical regulations and objectively identified results of research and development for road infrastructure. On the basis of the presented correlations, it can be stated that the presented research results can be used immediately for SR conditions in the design of road pavements.

  2. Fatigue and rutting strain analysis of flexible pavements designed ...

    African Journals Online (AJOL)

    ELO

    elastic analysis are that; i) The pavement structure is regarded as a linear elastic multilayered system in which the stress-strain solution of the material are characterized by the Young's modulus of. Elasticity E and poison's ratio µ. ii) Each layer has a finite thickness h except the lower. Ekwulo and Eme 413. P. µ1 = 0.5, h1, E1.

  3. Intelligent Design and Intelligent Failure

    Science.gov (United States)

    Jerman, Gregory

    2015-01-01

    Good Evening, my name is Greg Jerman and for nearly a quarter century I have been performing failure analysis on NASA's aerospace hardware. During that time I had the distinct privilege of keeping the Space Shuttle flying for two thirds of its history. I have analyzed a wide variety of failed hardware from simple electrical cables to cryogenic fuel tanks to high temperature turbine blades. During this time I have found that for all the time we spend intelligently designing things, we need to be equally intelligent about understanding why things fail. The NASA Flight Director for Apollo 13, Gene Kranz, is best known for the expression "Failure is not an option." However, NASA history is filled with failures both large and small, so it might be more accurate to say failure is inevitable. It is how we react and learn from our failures that makes the difference.

  4. Deterioration Models for Cement Bound Materials in Structural Design and Evaluation of Heavy Duty Pavements

    DEFF Research Database (Denmark)

    Skar, Asmus; Holst, Mogens Løvendorf

    Ports and industries require special types of pavements to resist the heavy static load from containers and continuous loads from operation vehicles. To reduce the risk of rutting and settlements over time concrete or compositepavement systems are typically applied. The structural design...... link between laboratory tests, design and field applications. First, a realistic 3-D cohesive finite element model for structural analysis of composite block pavement systems is developed. This model is used for verication and compared to experimental results. Secondly, a simplified two...... number of model parameters. In order to move a step towards more generalised structural design methods for analysis of heavy duty pavements, this study aims at developing a mechanistic approach based on constitutive models. A simple framework for engineering application is sought; creating a rational...

  5. Leveraging Failure in Design Research

    Science.gov (United States)

    Lobato, Joanne; Walters, C. David; Hohensee, Charles; Gruver, John; Diamond, Jaime Marie

    2015-01-01

    Even in the resource-rich, more ideal conditions of many design-based classroom interventions, unexpected events can lead to disappointing results in student learning. However, if later iterations in a design research study are more successful, the previous failures can provide opportunities for comparisons to reveal subtle differences in…

  6. Evaluation of a performance-based standards approach to heavy vehicle design to reduce pavement wear

    CSIR Research Space (South Africa)

    Nordengen, Paul A

    2013-11-01

    Full Text Available of the Australian PBS system while the infrastructure performance standards are based on South African bridge and pavement design standards. In order to optimise road wear per ton of payload, the South African Mechanistic-Empirical Design Method, which is the basis...

  7. Effects on evaporation rates from different water-permeable pavement designs.

    Science.gov (United States)

    Starke, P; Göbel, P; Coldewey, W G

    2011-01-01

    The urban water balance can be attenuated to the natural by water-permeable pavements (WPPs). Furthermore, WPPs have a 16% higher evaporation rate than impermeable pavements, which can lead to a better urban climate. Evaporation rates from pavements are influenced by the pavement surface and by the deeper layers. By a compared evaporation measurement between different WPP designs, the grain size distribution of the sub-base shows no influence on the evaporation rates in a significant way. On the contrary, a sub-base made of a twin-layer decreases the evaporation by 16% compared to a homogeneous sub-base. By a change in the colour of the paving stone, 19% higher evaporation rates could be achieved. A further comparison shows that the transpiration-effect of the grass in grass pavers increases the evaporation rates more than threefold to pervious concrete pavements. These high evapotranspiration rates can not be achieved with a pervious concrete paving stone. In spite of this, the broad field of application of the pervious concrete paving stone increases the importance in regard to the urban climate.

  8. Development of a catalog of resilient modulus values for aggregate base for use with the mechanistic-empirical pavement design guide (MEPDG).

    Science.gov (United States)

    2015-06-01

    Base aggregate is one of the intermediate layers in a pavement system for both flexible and rigid surfaces. Characterization : of base aggregate is necessary for pavement thickness design. Many transportation agencies, including the Virginia Departme...

  9. A multi-scale approach for near-surface pavement cracking and failure mechanisms

    Science.gov (United States)

    2010-10-31

    Nearsurface cracking is one of the predominant distress types in flexible pavements. The occurrence of : nearsurface cracking, also sometimes referred to as topdown cracking, has increased in recent years : with the increased construction of...

  10. Permanent deformation testing for a new South African mechanistic pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2012-01-01

    Full Text Available is to develop test protocols for hot-mix asphalt materials. To date, no permanent deformation test is incorporated into South African pavement design guides. The objective of this paper is to present the development process of a repeated load axial permanent...

  11. A preliminary study of mechanistic approach in pavement design to accommodate climate change effects

    Science.gov (United States)

    Harnaeni, S. R.; Pramesti, F. P.; Budiarto, A.; Setyawan, A.

    2018-03-01

    Road damage is caused by some factors, including climate changes, overload, and inappropriate procedure for material and development process. Meanwhile, climate change is a phenomenon which cannot be avoided. The effects observed include air temperature rise, sea level rise, rainfall changes, and the intensity of extreme weather phenomena. Previous studies had shown the impacts of climate changes on road damage. Therefore, several measures to anticipate the damage should be considered during the planning and construction in order to reduce the cost of road maintenance. There are three approaches generally applied in the design of flexible pavement thickness, namely mechanistic approach, mechanistic-empirical (ME) approach and empirical approach. The advantages of applying mechanistic approach or mechanistic-empirical (ME) approaches are its efficiency and reliability in the design of flexible pavement thickness as well as its capacity to accommodate climate changes in compared to empirical approach. However, generally, the design of flexible pavement thickness in Indonesia still applies empirical approach. This preliminary study aimed to emphasize the importance of the shifting towards a mechanistic approach in the design of flexible pavement thickness.

  12. A decision-making tool for incorporating sustainability measures into pavement design : research project capsule.

    Science.gov (United States)

    2016-10-01

    The objective of the proposed study is to conceive and develop a decision-making tool : for evaluating sustainability of pavement designs based on a cradle-to-grave analysis. : This tool will utilize EPDs to enhance the reliability of the assessment ...

  13. Asphalt Overlay Design Methods for Rigid Pavements Considering Rutting, Reflection Cracking, and Fatigue Cracking

    Science.gov (United States)

    1998-10-01

    The overall objectives of this study were (1) to provide basic performance evaluation of asphalt overlays on rigid pavements and (2) to provide a design tool for supporting a long-range rehabilitation plan for the US 59 : corridor in the Lufkin Distr...

  14. Revision of the South African flexible pavement design method; mechanistic-empirical components

    CSIR Research Space (South Africa)

    Theyse, HL

    2007-09-01

    Full Text Available The current version of the South African Mechanistic –Empirical Design Method for flexible pavements is based on technology and models developed during the 1970’s and 1980’s. Given the current level of concern regarding the validity of the results...

  15. Forensic study into the causes of premature failures in asphalt pavements in Tanzania

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2015-11-01

    Full Text Available by TANROADS has attributed the premature failures to the advent of wide base (“super single”) tyres on their roads (Report No.C22, 2014). Rutting in asphalt concrete layers is one of the most frequent and more serious distresses associated with asphalt... due to poor asphalt mix design resulting in shear failure. The most common cause of this failure is associated with routes with heavy loads and high tyre pressures. A more detailed discussion and practical consideration based on the information...

  16. Recreation of Small Strains Phenomenon under Pavement Structure and Consequences of Failure to Address It

    Science.gov (United States)

    Fedorowicz, Lidia; Kadela, Marta

    2017-10-01

    This paper describes the small strains phenomenon which occurs in the subgrade under a pavement, a phenomenon documented through in-situ tests and recreated in numerical analyses, which lends a practical engineering aspect to the subject matter. The analyses were preceded by: 1) presentation of the role of constitutive models in structure-subgrade system analysis, 2) reference to methods of modelling in mechanistic procedures and possibility of reliable assessment of criterial values in road structures. These studies were coupled with a description of field tests, which recorded strains in subgrade under a loaded pavement: in zone I directly under the pavement – variable, depending on stiffness of the pavement and the load (about 200÷1000.10-6) and below that, in zone II – ‘stabilised’ (about 1÷5.10-6). In summary, it has been found that the accuracy of numerical analyses of structure-subgrade systems is dependent on the adopted constitutive model of the soil and the numerical calculation area representing the subgrade. Recreation and analysis of the pavement-subgrade system behaviour employed the MCC(OC) critical state model. It was determined that a reliable response of the computational model to the load path used can be obtained with a model that has been previously properly calibrated. The paper justifies the need to carry out further, directed field tests, coupled with numerical analyses employing relevant constitutive models for description of the soil’s performance.

  17. Use of the 1993 AASHTO Guide, MEPDG and historical performance to update the WSDOT Pavement Design Catalog.

    Science.gov (United States)

    2011-09-01

    "This report describes the preparation of a revised pavement thickness design catalog for the Washington State Department of Transportation (WSDOT) using the 1993 American Association of State Highway and Transportation Officials (AASHTO) Guide, the ...

  18. Appraisal of the Causes of Pavement

    African Journals Online (AJOL)

    used environmental observations in addition to geotechnical test to study ... 1Department of Applied Geophysics, Federal University of Technology, Akure, Nigeria ... have contributed to the pavement failure. Keywords: Remote Sensing, Geotechnical Investigation, Road Pavement Failure, Basement Complex. Environment.

  19. Stress Regression Analysis of Asphalt Concrete Deck Pavement Based on Orthogonal Experimental Design and Interlayer Contact

    Science.gov (United States)

    Wang, Xuntao; Feng, Jianhu; Wang, Hu; Hong, Shidi; Zheng, Supei

    2018-03-01

    A three-dimensional finite element box girder bridge and its asphalt concrete deck pavement were established by ANSYS software, and the interlayer bonding condition of asphalt concrete deck pavement was assumed to be contact bonding condition. Orthogonal experimental design is used to arrange the testing plans of material parameters, and an evaluation of the effect of different material parameters in the mechanical response of asphalt concrete surface layer was conducted by multiple linear regression model and using the results from the finite element analysis. Results indicated that stress regression equations can well predict the stress of the asphalt concrete surface layer, and elastic modulus of waterproof layer has a significant influence on stress values of asphalt concrete surface layer.

  20. Design, development, and application of precast and prestressed concrete system for rigid pavement in Indonesia

    Science.gov (United States)

    Nurjaman, Hari; Faizal, Lutfi; Suaryana, Nyoman; Hariandja, Binsar; Gambiro, Purnomo, Wicaksono, Siswo

    2017-11-01

    The performance of highways in Indonesia until today is yet to be optimum. Flexible or rigid pavement construction generally do not reach designed service lives, either due to the fact that the construction do not meet specifications or unavoidable excessive load. Precast and prestressed concrete system has been applied since 2007, but unfortunately the application has not been optimum due to the fact that the construction method is not integrally carried out. This paper deals with a construction concept that developed in 2015-2017. The concept applies green construction based on integrated manufacture industry, starting from design, construction, function, maintenance and demolition. The concept is applied on the three highway sub-layers, i.e., sub grade, sub base, and surface, and drainage system. Sub grade improvement may use soil dislocation, chemical improvement or concrete matress. Sub base material uses foam mortar, which is material easy in quality control compared to conventional materials. Pavement material uses precast and prestressed concrete components with controlled quality, quickly function as flexible pavement, and moreover, may anticipate excessive loadings. Cost estimation is carried out integrated by life cycle cost: initial investment, obstruction while construction, and maintenance cost during operation. This innovation has passed tests in technical construction method aspects as well as construction work in 2015-2017, so it is available to support infrastructure construction acceleration which achieves quality demanded to date.

  1. Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design

    Science.gov (United States)

    Solanki, Pranshoo

    Pavements are vulnerable to subgrade layer performance because it acts as a foundation. Due to increase in the truck traffic, pavement engineers are challenged to build more strong and long-lasting pavements. To increase the load-bearing capacity of pavements, subgrade layer is often stabilized with cementitious additives. Thus, an overall characterization of stabilized subgrade layer is important for enhanced short- and long-term pavement performance. In this study, the effect of type and amount of additive on the short-term performance in terms of material properties recommended by the new Mechanistic-Empirical Pavement Design Guide (MEPDG) is examined. A total of four soils commonly encountered as subgrades in Oklahoma are utilized. Results show that the changes in the Mr, ME and UCS values stabilized specimens depend on the soil type and properties of additives. The long-term performance (or durability) of stabilized soil specimens is investigated by conducting freeze-thaw (F-T) cycling, vacuum saturation and tube suction tests on 7-day cured P-, K- and C-soil specimens stabilized with 6% lime, 10% CFA and 10% CKD. This study is motivated by the fact that during the service life of pavement stabilized layers are subjected to F-T cycles and moisture variations. It is found that that UCS value of all the stabilized specimens decreased with increase in the number of F-T cycles. A strong correlation was observed between UCS values retained after vacuum saturation and F-T cycles indicating that vacuum saturation could be used as a time-efficient and inexpensive method for evaluating durability of stabilized soils. In this study, short- and long-term observations from stabilization of sulfate bearing soil with locally available low (CFA), moderate (CKD) and high (lime) calcium-based stabilizers are determined to evaluate and compare the effect of additive type on the phenomenon of sulfate-induced heave. The impact of different factors on the development of the

  2. Considerations for rigid vs. flexible pavement designs when allowed as alternate bids : technical report.

    Science.gov (United States)

    2009-08-01

    This report documents the research conducted for the Texas Department of Transportation (TxDOT) : concerning the use of pavement alternates. The scope of the project includes reviewing the state-of-thepractice : in methods used for pavement type sele...

  3. Training development for pavement preservation.

    Science.gov (United States)

    2013-05-01

    This research project strives to help the Iowa Department of Transportation (DOT) fully achieve the full benefits of pavement : preservation through training on proper selection, design, and application of pavement preservation treatments. In some ca...

  4. Large stone asphalt mix design for heavy duty asphalt pavements

    CSIR Research Space (South Africa)

    Rust, FC

    1990-08-01

    Full Text Available The recent increase in traffic volumes and also axle loads on some of the major routes in South Africa has extended the traffic classes beyond the current highest design class. Additionally there is a strong lobby to increase the legal axle load...

  5. Effect Assessment the Impact of Filler Types on the Input Design Parameter of Flexible Pavements

    Directory of Open Access Journals (Sweden)

    Sahar S. Neham

    2017-08-01

    Full Text Available To meet the requirements of flexible pavements (safety, economy, limited the stresses on the natural subgrade and a smooth ride, good quality material of surface course must be used so to prevent pavement distresses caused by the different types of loadings (structural and environmental loadings, while the resilient modulus is important input data when flexible pavement was designed, it is selected to show its effect by different types of mineral filler as a partial replacement. In this paving mix, to improve the quality of the mix material and to represent the effect of these replacements materials on the elastic characterization by measuring the resilient modulus of hot mix asphalt (HMA: Fly Ash (FA, Ordinary Portland Cement (OPC, Hydrated Lime (HL and Silica Fume (SF are used as a partial percent of filler (Limestone Dust (LSD replacement, where these materials are locally available including (40-50 penetration grade asphalt binder. To achieve the goal of study; asphalt concrete mixes are prepared at their optimum asphalt content using Marshall Method of mix design. Four replacement percent’s were used; 0, 1.5, 3.0 and 4.5 percent by total weight of aggregate for each filler types. According to ASTM D4123 criteria (Resilient Modulus was tested by UTM¬25. Mixes modified with (FA, (OPC, (HL and (SF were found to have average improvement in the value of Resilient Modulus by (13.37, 9.63, 11.14, 24.00 % at 1.5 percent of filler replacement and by (24.54, 16.63, 18.73, 38.31 % at 3.0 percent of filler replacement also the percent of improvement is: (39.55, 26.36, 29.82, 58.30 at 4.5percent of filler replacement sequentially.

  6. Texas flexible pavements overlays : review and analysis of existing databases.

    Science.gov (United States)

    2011-12-01

    Proper calibration of pavement design and rehabilitation performance models to : conditions in Texas is essential for cost-effective flexible pavement design. The degree of : excellence with which TxDOTs pavement design models is calibrated will d...

  7. A novel finite element method for designing floor slabs on grade and pavements with loads at edges

    Directory of Open Access Journals (Sweden)

    Hugo Ernesto Camero Sanabria

    2015-05-01

    Full Text Available In the present paper a methodology to design slabs on grade for industrial floors and pavements using bi-dimensional finite elements and integrating the subgrade in the design is presented. The suggested method to design slabs on grade for industrial floors and pavements has been called the Camero Finite Element Method.  An example of an industrial floor designed to be capable of sustaining an infinite number of load applications (or a 50 years lifespan period is here presented in order to be compared with the results of the Camero Finite Element Method, the PCA (Portland Cement Association, and the WRI’s (Wire Reinforcement Institute simplified methods. In this example, an industrial floor is designed to be capable of sustaining an infinite number of load applications comparing the results of the Camero Finite Element Method and the simplified methods of the PCA and WRI. The industrial floor or pavement will be able to resist an infinite number of load applications if it is designed with the Camero Finite Element Method. On the other hand, if it is designed using the PCA and the WRI methods, it will last a few years (in this example, in one year period, the number of axle load applications is equal to the number of allowable repetitions. To conclude, if an industrial floor o pavement is designed with the Camero Finite Element Method, it will be able to sustain an infinite number of load applications (up to 50 years lifespan period.

  8. Safety effectiveness of pavement design treatment at intersections: Left turning vehicles and pedestrians on crosswalks

    Directory of Open Access Journals (Sweden)

    Hasina Iasmin

    2016-07-01

    Full Text Available Pedestrians are the most vulnerable road users as they are more exposed than other road users. Pedestrian safety at road intersections still remains the most vital and yet unsolved issue. One of the critical points in pedestrian safety is the occurrence of accidents between left-turning vehicle and pedestrians on crosswalks at signalized intersections. A crosswalk is a place designated for pedestrians and cyclists to cross vehicular roads safely. Drivers are expected to give priority to pedestrians or cyclists during interactions between them on the crosswalk. If a driver exhibits non-yielding behavior, the interaction will turn into a collision. This study examined the safety effect of three crosswalks designed with different materials such as red-colored material or brick pavement based on a safety performance study. The safety performance study considered left-turning driver's gap acceptance behavior and the severity of traffic conflict events between left-turning vehicles and pedestrians. The results of the study indicates that using brick pavement on a crosswalk increases the safety level of the crosswalk. Drivers at such crosswalks are more acquiescent to the priority rule.

  9. Consideration of pavement roughness effects on vehicle-pavement interaction

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2001-07-01

    Full Text Available The aim of this paper is to present some of the results of the vehicle-pavement interaction project, mainly in terms of the expected effects of pavement roughness on the moving dynamic effects in pavement analysis and design. Background is provided...

  10. Structural Design and Economic Evaluation of Roller Compacted Concrete Pavement with Recycled Aggregates

    Science.gov (United States)

    Abut, Yavuz; Taner Yildirim, Salih

    2017-10-01

    Using recycled aggregates in the concrete offers advantages in many areas such as waste management, energy save and natural resources, conservation of ecological balance, low CO2 emissions, and users are encouraged in this regard to use these materials. In this study, the profit / loss account arising in the structural design phase was investigated when Reclaimed Asphalt Pavement (RAP), which is limited to use in Roller Compacted Concrete (RCC) pavements, was used as coarse aggregate. RAP materials were used as coarse aggregates by the levels of 0%, 15% and 20% and mechanical properties such as compressive strength, flexural strength, splitting tensile strength and modulus of elasticity were investigated. In the last stage, the mechanical properties obtained from these experimental studies were entered into KENSLABS software as input, and the slab layer thicknesses were determined according to three different subgrade conditions and a certain fatigue criterion. According to the results, it has been determined that the use of RAP at a level of 20% is a serious reducing effect on mechanical properties and and the use of RAP at a level of 15% does not bring a great economic benefit but it is reasonable to use it as coarse aggregate in RCC mixes in consideration of environmental effects.

  11. Resilient response characterisation of hot-mix asphalt mixes for a new South African pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2011-09-01

    Full Text Available The South Africa National Road Agency Ltd (SANRAL) is in the process of revising the South African Pavement Design Method (SAPDM). A necessary part of this programme is to develop resilient response models. Dynamic (complex) modulus has been used...

  12. Stabilized Base Courses for Advanced Pavement Design Report 1: Literature Review and Field Performance Data

    National Research Council Canada - National Science Library

    Grogan, William

    1999-01-01

    .... Field data collected included structural data in the form of nondestructive testing (NDT) performed with a falling weight deflectometer, visual condition survey using the pavement condition index...

  13. A multi\\0x2010scale approach for near\\0x2010surface pavement cracking and failure mechanisms.

    Science.gov (United States)

    2010-11-30

    Nearsurface cracking is one of the predominant distress types in flexible pavements. The occurrence of : nearsurface cracking, also sometimes referred to as topdown cracking, has increased in recent years : with the increased construction of...

  14. Performance evaluation of Arizona's LTPP SPS-9 Project : strategic study of flexible pavement mix design factors.

    Science.gov (United States)

    2016-01-01

    As part of the Long Term Pavement Performance (LTPP) Program, the Arizona Department of Transportation (ADOT) constructed five Specific Pavement Studies 9 (SPS9) test sections on U.S. Route 93 near Kingman. This project, SPS9B, studied the effe...

  15. CRITICAL MECHANICAL PROPERTIES OF STRUCTURAL LIGHT-WEIGHT CONCRETE AND THE EFFECTS OF THESE PROPERTIES ON THE DESIGN OF THE PAVEMENT STRUCTURE.

    Science.gov (United States)

    1965-01-01

    In this study, critical mechanical properties of structural lightweight concrete were determined and utilized in the evaluation of a design of concrete pavements. Also presented are the critical mechanical properties resulting from unrestrained and r...

  16. Tire-Pavement Friction Characteristics with Elastic Properties of Asphalt Pavements

    Directory of Open Access Journals (Sweden)

    Miao Yu

    2017-11-01

    Full Text Available The skid-resisting performance of pavement is a critical factor in traffic safety. Recent studies primarily analyze this behavior by examining the macro or micro texture of the pavement. It is inevitable that skid-resistance declines with time because the texture of pavement deteriorates throughout its service life. The primary objective of this paper is to evaluate the use of different asphalt pavements, varying in resilience, to optimize braking performance on pavement. Based on the systematic dynamics of tire-pavement contact, and analysis of the tire-road coupled friction mechanism and the effect of enlarging the tire-pavement contact area, road skid resistance was investigated by altering the elastic modulus of asphalt pavement. First, this research constructed the kinetic contact model to simulate tire-pavement friction. Next, the following aspects of contact behaviors were studied when braking: tread deformation in the tangential pavement interface, actual tire-pavement contact in the course, and the frictional braking force transmitted from the pavement to the tires. It was observed that with improvements in pavement elasticity, the actual tire-pavement contact area increased, which gives us the ability to effectively strengthen the frictional adhesion of the tire to the pavement. It should not be overlooked that the improvement in skid resistance was caused by an increase in pavement elasticity. This research approach provides a theoretical basis and design reference for the anti-skid research of asphalt pavements.

  17. Impact of Truck Loading on Design and Analysis of Asphaltic Pavement Structures : Phase II

    Science.gov (United States)

    2011-02-01

    In this study, Schaperys nonlinear viscoelastic constitutive model is implemented into the commercial finite element (FE) software ABAQUS via user defined subroutine (user material, or UMAT) to analyze asphalt pavement subjected to heavy truck loa...

  18. Flexible and composite structures for premium pavements. Volume 1, Development of design procedure

    Science.gov (United States)

    1980-11-01

    This document provides results of a detailed study to identify flexible and composite structures which will perform as zero-maintenance pavements. To accomplish this, the report identifies the major distress types which have seriously limited the mai...

  19. Use of Ground Penetrating Radar at the FAA's National Airport Pavement Test Facility

    Science.gov (United States)

    Injun, Song

    2015-04-01

    The Federal Aviation Administration (FAA) in the United States has used a ground-coupled Ground Penetrating Radar (GPR) at the National Airport Pavement Test Facility (NAPTF) since 2005. One of the primary objectives of the testing at the facility is to provide full-scale pavement response and failure information for use in airplane landing gear design and configuration studies. During the traffic testing at the facility, a GSSI GPR system was used to develop new procedures for monitoring Hot Mix Asphalt (HMA) pavement density changes that is directly related to pavement failure. After reviewing current setups for data acquisition software and procedures for identifying different pavement layers, dielectric constant and pavement thickness were selected as dominant parameters controlling HMA properties provided by GPR. A new methodology showing HMA density changes in terms of dielectric constant variations, called dielectric sweep test, was developed and applied in full-scale pavement test. The dielectric constant changes were successfully monitored with increasing airplane traffic numbers. The changes were compared to pavement performance data (permanent deformation). The measured dielectric constants based on the known HMA thicknesses were also compared with computed dielectric constants using an equation from ASTM D4748-98 Standard Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radar. Six inches diameter cylindrical cores were taken after construction and traffic testing for the HMA layer bulk specific gravity. The measured bulk specific gravity was also compared to monitor HMA density changes caused by aircraft traffic conditions. Additionally this presentation will review the applications of the FAA's ground-coupled GPR on embedded rebar identification in concrete pavement, sewer pipes in soil, and gage identifications in 3D plots.

  20. High Performance Concrete Pavement in Indiana

    OpenAIRE

    Nantung, Tommy E

    2011-01-01

    Until the early 1990s, curling and warping of Portland cement concrete pavement did not concern pavement engineers in many transportation agencies. Since beginning construction of the interstate system in the United States in the late 1950s through the late 1980s, the performance of Portland cement concrete pavement has been associated with properties of concrete as a pavement material. In those years developed standards and design guidelines emphasized better concrete materials and construct...

  1. Hot-mix asphalt testing for the South African pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2010-08-01

    Full Text Available of local and international hot-mix asphalt (HMA) test methods and modify or adapt them to suit South African road pavement conditions. This paper presents various laboratory HMA test protocols developed as part of the project to revise SAPDM. Large scale...

  2. Comparison of permeable pavement types : hydrology, design, installation, maintenance and cost.

    Science.gov (United States)

    2012-01-13

    "WisDOTs regional storm water engineer for the Southeast Region is interested in developing a park-and-ride with : porous pavement, possibly with the PaveDrain brand of permeable block. Research was needed to determine how : well permeable pavemen...

  3. Towards the application of stress-in-motion (SIM) results in pavement design and infrastructure protection

    CSIR Research Space (South Africa)

    De Beer, Morris

    2004-03-01

    Full Text Available The aim of this paper is to highlight the approach and application of the Stress-In-Motion (SIM) technology to assist in an improved definition of the actual tyre / pavement interaction of modern heavy vehicles and their loads on the current road...

  4. Toward the Design of an Induction Heating System for Asphalt Pavements with the Finite Element Method

    NARCIS (Netherlands)

    Apostolidis, P.; Liu, X.; Kasbergen, C.; Scarpas, Athanasios; van de Ven, M.F.C.

    2017-01-01

    Induction technology was introduced to the paving industry to assist pavement operations by heating asphalt layers efficiently from the surface. Many experimental studies have been conducted to investigate the impact of inductive particles on the heating efficiency of asphalt mixes. However,

  5. Modelling tyre-road contact stresses in pavement design and analysis

    CSIR Research Space (South Africa)

    Maina, JW

    2013-07-01

    Full Text Available distribution is idealised with a multitude of circular and rectangular shapes, mimicking the non-uniform characteristics of the contact stresses inside the tyre contact patch. An example, in terms of pavement layer life and strain energy of distortion, is given...

  6. Comparison study on flexible pavement design using FAA (Federal Aviation Administration) and LCN (Load Classification Number) code in Ahmad Yani international airport’s runway

    Science.gov (United States)

    Santoso, S. E.; Sulistiono, D.; Mawardi, A. F.

    2017-11-01

    FAA code for airport design has been broadly used by Indonesian Ministry of Aviation since decades ago. However, there is not much comprehensive study about its relevance and efficiency towards current situation in Indonesia. Therefore, a further comparison study on flexible pavement design for airport runway using comparable method has become essential. The main focus of this study is to compare which method between FAA and LCN that offer the most efficient and effective way in runway pavement planning. The comparative methods in this study mainly use the variety of variable approach. FAA code for instance, will use the approach on the aircraft’s maximum take-off weight and annual departure. Whilst LCN code use the variable of equivalent single wheel load and tire pressure. Based on the variables mentioned above, a further classification and rated method will be used to determine which code is best implemented. According to the analysis, it is clear that FAA method is the most effective way to plan runway design in Indonesia with consecutively total pavement thickness of 127cm and LCN method total pavement thickness of 70cm. Although, FAA total pavement is thicker that LCN its relevance towards sustainable and pristine condition in the future has become an essential aspect to consider in design and planning.

  7. Evaluation of Long-Life Concrete Pavement Practices for Use in Florida : [Summary

    Science.gov (United States)

    2012-01-01

    Current Florida construction practices produce asphalt pavements with a service life of 12 to 20 years before needing rehabilitation; concrete pavements are typically designed for 20 years. However, pavements with much longer design lives are possibl...

  8. Evaluation of Long-Life Concrete Pavement Practices for Use in Florida

    Science.gov (United States)

    2012-11-01

    Current Florida construction practices produce asphalt pavements with a service life of 12 to 20 years before needing rehabilitation; concrete pavements are typically designed for 20 years. However, pavements with much longer design lives are possibl...

  9. Long-term pavement performance pavement loading user guide (LTPP PLUG).

    Science.gov (United States)

    2013-10-01

    "This guide addresses the selection and use of axle loading defaults for Mechanistic-Empirical Pavement Design : Guide (MEPDG) applications. The defaults were developed based on weigh-in-motion (WIM) data from the Long- : Term Pavement Performance (L...

  10. Impact of pavement conditions on crash severity.

    Science.gov (United States)

    Li, Yingfeng; Liu, Chunxiao; Ding, Liang

    2013-10-01

    Pavement condition has been known as a key factor related to ride quality, but it is less clear how exactly pavement conditions are related to traffic crashes. The researchers used Geographic Information System (GIS) to link Texas Department of Transportation (TxDOT) Crash Record Information System (CRIS) data and Pavement Management Information System (PMIS) data, which provided an opportunity to examine the impact of pavement conditions on traffic crashes in depth. The study analyzed the correlation between several key pavement condition ratings or scores and crash severity based on a large number of crashes in Texas between 2008 and 2009. The results in general suggested that poor pavement condition scores and ratings were associated with proportionally more severe crashes, but very poor pavement conditions were actually associated with less severe crashes. Very good pavement conditions might induce speeding behaviors and therefore could have caused more severe crashes, especially on non-freeway arterials and during favorable driving conditions. In addition, the results showed that the effects of pavement conditions on crash severity were more evident for passenger vehicles than for commercial vehicles. These results provide insights on how pavement conditions may have contributed to crashes, which may be valuable for safety improvement during pavement design and maintenance. Readers should notice that, although the study found statistically significant effects of pavement variables on crash severity, the effects were rather minor in reality as suggested by frequency analyses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Determination of coefficient of thermal expansion for Portland Cement Concrete pavements for MEPDG Implementation

    Science.gov (United States)

    2012-10-01

    The Coefficient of Thermal Expansion (CTE) is an important parameter in Portland Cement Concrete (PCC) pavement analysis and design as it is directly proportional to the magnitude of temperature-related pavement deformations throughout the pavement s...

  12. Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces

    Science.gov (United States)

    1997-03-18

    This advisory circular (AC) contains guidelines and procedures for the design : and construction of skid-resistant pavement, pavement evaluation with friction : measuring equipment, and maintenance of high skid-resistant pavements. 45p.

  13. Guidelines for PCC inputs to AASHTOWare Pavement ME.

    Science.gov (United States)

    2014-12-01

    The objective of this research study was to develop guidelines for portland cement concrete (PCC) material inputs to the : AASHTOWare Pavement ME Design program. The AASHTOWare Pavement ME Design is the software program used by the : Mississippi Depa...

  14. Program computes single-point failures in critical system designs

    Science.gov (United States)

    Brown, W. R.

    1967-01-01

    Computer program analyzes the designs of critical systems that will either prove the design is free of single-point failures or detect each member of the population of single-point failures inherent in a system design. This program should find application in the checkout of redundant circuits and digital systems.

  15. Permeable Pavements at Purdue

    OpenAIRE

    Knapp, Jim

    2013-01-01

    Two case studies will be presented describing sustainable drainage alternatives. The processes used for the 2nd Street project in Seymour will provide a comparison of the design processes for conventional and green infrastructure solutions. Purdue University will discuss a number of permeable pavement installations on campus and provide a map for viewing. Asphalt, concrete, and permeable paver options will be discussed.

  16. Research on Fiber Micro-Surfacing Mixture Design and Pavement Performance in Interchange’s Connections

    Directory of Open Access Journals (Sweden)

    Wu Zhaoyang

    2015-01-01

    Full Text Available In order to use the micro-surfacing which is the existing micro-surfacing technology guide that has some technical defects, the method to determine the optimal dosage of emulsified asphalt and best whetstone is not very reasonable, and it impedes the application and development of micro-surfacing technology to improve the performance of the pavement. In this paper, the “graphical method” is first used to determine the optimal dosage range of emulsified asphalt. Nowadays, a large number of expressways reach the stage of repair and maintenance. Interchange ramp exit and entrance are always the accident-prone sections and, it’s easy to over-look the pavement’s skid resistance of those areas. Micro-surfacing can significantly improve the performance of pavement, especially the skid resistance. Verified with laboratory tests, it recommends that the dosage of emulsified asphalt corresponding to the peak of flexural strain measured with low temperature bending test as OAC of micro-surfacing mixture shows technical superiority. The use of fiber micro-surfacing at the ramp’s exit and entrance can reduce the braking distance.

  17. Effects of Asphalt Mix Design Properties on Pavement Performance: A Mechanistic Approach

    Directory of Open Access Journals (Sweden)

    Ahmad M. Abu Abdo

    2016-01-01

    Full Text Available The main objective of this study was to investigate the effects of hot mix asphalt material properties on the performance of flexible pavements via mechanistic approach. 3D Move Analysis software was utilized to determine rutting and cracking distresses in an asphalt concrete (AC layer. Fourteen different Superpave mixes were evaluated by utilizing results of the Dynamic Modulus (|E⁎| Test and the Dynamic Shear Modulus (|G⁎| Test. Results showed that with the increase of binder content, the tendency of rutting in AC layer increased. However, with the increase of binder content, the cracking of AC layer lessened. Furthermore, when different binder grades were evaluated, results showed that with the increase of the upper binder grade number, rutting decreased, and with the increase of the lower binder grade number, rutting increased. Furthermore, analysis showed that with the increase of the lower binder grade number, higher percent of bottom up cracks would result. As a result of the analysis, binder grade should not be solely considered for cracking in AC layer; binder content and aggregate structure play a big role. Finally, results illustrated that the mechanistic approach is a better tool to determine the performance of asphalt pavement than commonly used methods.

  18. Pavement thickness evaluation using ground penetrating radar

    Science.gov (United States)

    Harris, Dwayne Arthur

    Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement management and design. Much of the time this information is missing, out of date, or unknown for highway sections. Current technologies for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement thickness information; however, it is also time consuming, labor intensive, intrusive to traffic, destructive, and limited in coverage. FWD provides nondestructive estimates of both a surface thickness and total pavement structure thickness, including pavement, base and sub-base. On the other hand, FWD is intrusive to traffic and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement surface course thickness estimates with excellent data coverage at highway speed. Yet, disadvantages include the pavement thickness estimation being affected by the electrical properties of the pavement, limitations of the system utilized, and heavy post processing of the data. Nevertheless, GPR has been successfully utilized by a number of departments of transportation (DOTs) for pavement thickness evaluation. This research presents the GPR thickness evaluation methods, develops GPRPAVZ the software used to implement the methodologies, and addresses the quality of GPR pavement thickness evaluation.

  19. Pavement Evaluation and Overlay Design Using Vibratory Nondestructive Testing and Layered Elastic Theory. Volume I. Development of Procedure.

    Science.gov (United States)

    1980-03-01

    MAR AX R A WEISS DOT-FA73WAX-377 UNCLAS7SIFIED FAA-RD-77-186-VOL-1 NL I sport H. FAA-I-/-II.I PAVEMENT EVALUATION AND OVERLAY DESIGN USING VIBRATORY...00003300 665* WE’CCI 00003305 666* VMR =VM+BC2*SCO*( (BC1-FREQR)/OMEGR)**2 00003310 667* WR= VMR *AG/16.0 00003315 668* OMEG=OMEGT 00003320 669* RBA𔃾.0...2)/SOT**4 00003375 680m ADYNT=(FDYNT/SOT)*(1.0.ALPH1*FPSIT+ALPH2*FPSIT**2) 00003380 681* OMETR=SQRT(SKOT/ VMR ) 00003385 .1682* OM-(C1,BBF*BBA*(AOYN**2

  20. Puzzles in modern biology. I. Male sterility, failure reveals design.

    Science.gov (United States)

    Frank, Steven A

    2016-01-01

    Many human males produce dysfunctional sperm. Various plants frequently abort pollen. Hybrid matings often produce sterile males. Widespread male sterility is puzzling. Natural selection prunes reproductive failure. Puzzling failure implies something that we do not understand about how organisms are designed. Solving the puzzle reveals the hidden processes of design.

  1. Geomaterial characterizations of full scale pavement test sections for mechanistic analysis and design

    CSIR Research Space (South Africa)

    Kwon, J

    2007-02-01

    Full Text Available rate (inches/blow) of DCP. Accordingly, the DCP based evaluation of the test strip soil CBR values ranged from 5 to 28% before the top subgrade soils were prepared for pavement construction. Moisture Content, % 6 8 10 12 14 16 18 20 D ry D... en sit y, kN /m 3 15.7 16.5 17.3 18.1 18.8 19.6 20.4 C BR , % 0 5 10 15 20 25 30 Moisture-Density CBR Maximum Dry Density = 19.3 kN/m3 Optimum Moisture Content = 11.2 % CBR = 4 Dry Density = 18.9 kN/m3 Moisture Content...

  2. Evaluating life cycle costs of perpetual pavements in China using operational pavement management system

    Directory of Open Access Journals (Sweden)

    Saud A. Sultan

    2016-10-01

    Full Text Available Highway transportation is considered as vital factor in China’s economic growth; many high grade highways have been constructed in China during the last decades. The research and application of perpetual asphalt pavement (PP technology have been deployed in China since 2000. The semi-rigid pavement has been normally considered as typical pavement of high class highways in the design according to the Chinese experience. The objective of this research is to evaluate the performance of different Chinese perpetual pavements using operational pavement management system and to examine its suitability for use in the design and construction of more economical and durable pavements. It has been found that the use of thin asphalt layers over semi-rigid pavement foundation in PP structure will create more sustainable, economical, and durable PP structures in comparison with typical thick asphalt layers PP structures.

  3. Long term pavement performance computed parameter : frost penetration

    Science.gov (United States)

    2008-11-01

    As the pavement design process moves toward mechanistic-empirical techniques, knowledge of seasonal changes in pavement structural characteristics becomes critical. Specifically, frost penetration information is necessary for determining the effect o...

  4. Predicting low-temperature cracking in asphalt pavements : [research brief].

    Science.gov (United States)

    2011-12-01

    In Wisconsin's winter climate, low temperatures can cause asphalt pavements to contract and crack, reducing their ride quality and service lives. To help engineers more accurately determine how well certain pavement designs will fare in such conditio...

  5. Long-term Performance of Granular Bases Including the Effect of Wet-Dry Cycles on Inverted Base Pavement Performance

    Science.gov (United States)

    2017-06-01

    The main objective of this study was to advance the understanding of alternative pavement designs. In particular, potential techniques such as inverted base pavements (IBP) have increased the importance of granular aggregate bases (GAB) in pavement s...

  6. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios

    2017-05-11

    Inverted base pavements involve a well-compacted granular aggregate base built between a thin asphalt concrete layer and a cement-treated base. Inverted base pavements can be constructed using conventional equipment and procedures but require proper quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost. Inverted base pavements rely on the complementary interaction between layers. The cement-treated base provides a stiff foundation for efficient compaction and constrains the deformation of the stress-sensitive granular aggregate base. The thin asphalt surface layer deforms as a membrane and develops low tensile stress. Additional large-scale field tests should be conducted to assess the performance of inverted base pavement designs in a wide range of conditions relevant to the USA.

  7. Evaluation of the fatigue and toughness of fiber reinforced concrete for use as a new highway pavement design : tech summary.

    Science.gov (United States)

    2016-04-01

    This study presents the fi rst approach to develop a new concrete pavement structure reinforced only with fi bers. This : research will identify probable combinations of fi bers (dosage and length combinations) that will adequately perform : in repea...

  8. Elementary students' engagement in failure-prone engineering design tasks

    Science.gov (United States)

    Andrews, Chelsea Joy

    Although engineering education has been practiced at the undergraduate level for over a century, only fairly recently has the field broadened to include the elementary level; the pre-college division of the American Society of Engineering Education was established in 2003. As a result, while recent education standards require engineering in elementary schools, current studies are still filling in basic research on how best to design and implement elementary engineering activities. One area in need of investigation is how students engage with physical failure in design tasks. In this dissertation, I explore how upper elementary students engage in failure-prone engineering design tasks in an out-of-school environment. In a series of three empirical case studies, I look closely at how students evaluate failed tests and decide on changes to their design constructions, how their reasoning evolves as they repeatedly encounter physical failure, and how students and facilitators co-construct testing norms where repetitive failure is manageable. I also briefly investigate how students' engagement differs in a task that features near-immediate success. By closely examining student groups' discourse and their interactions with their design constructions, I found that these students: are able to engage in iteration and see failure-as-feedback with minimal externally-imposed structure; seem to be designing in a more sophisticated manner, attending to multiple causal factors, after experiencing repetitive failure; and are able to manage the stress and frustration of repetitive failure, provided the co-constructed testing norms of the workshop environment are supportive of failure management. These results have both pedagogical implications, in terms of how to create and facilitate design tasks, and methodological implications--namely, I highlight the particular insights afforded by a case study approach for analyzing engagement in design tasks.

  9. Effect of age of permeable pavements on their infiltration function

    NARCIS (Netherlands)

    Terry Lucke; ir. Floris Boogaard; Simon Beecham

    2013-01-01

    This study describes field investigations designed to compare the infiltration capacities of 55 permeable pavement systems installed in the Netherlands and in Australia. The ages of the pavements varied from 1 to 12 years. Using infiltrometer testing, the performance of the pavements has been

  10. Rigid pavements distresses - pavement condition index evaluation

    OpenAIRE

    Pereira, Tiago David da Costa Prudente

    2014-01-01

    Pavements require maintenance in order to provide good service levels during their life period. Because of the significant costs of this operation and the importance of a proper planning, a pavement evaluation methodology, named Pavement Condition Index (PCI), was created by the U.S. Army Corps of Engineers. This methodology allows for the evaluation of the pavement condition along the life period, generally yearly, with minimum costs and, in this way, it is possible to plan the maintenance a...

  11. Failure is an option: Reactions to failure in elementary engineering design projects

    Science.gov (United States)

    Johnson, Matthew M.

    Recent reform documents in science education have called for teachers to use epistemic practices of science and engineering researchers to teach disciplinary content (NRC, 2007; NRC, 2012; NGSS Lead States, 2013). Although this creates challenges for classroom teachers unfamiliar with engineering, it has created a need for high quality research about how students and teachers engage in engineering activities to improve curriculum development and teaching pedagogy. While framers of the Next Generation Science Standards (NRC, 2012; NGSS Lead States 2013) focused on the similarities of the practices of science researchers and engineering designers, some have proposed that engineering has a unique set of epistemic practices, including improving from failure (Cunningham & Carlsen, 2014; Cunningham & Kelly, in review). While no one will deny failures occur in science, failure in engineering is thought of in fundamentally different ways. In the study presented here, video data from eight classes of elementary students engaged in one of two civil engineering units were analyzed using methods borrowed from psychology, anthropology, and sociolinguistics to investigate: 1) the nature of failure in elementary engineering design; 2) the ways in which teachers react to failure; and 3) how the collective actions of students and teachers support or constrain improvement in engineering design. I propose new ways of considering the types and causes of failure, and note three teacher reactions to failure: the manager, the cheerleader, and the strategic partner. Because the goal of iteration in engineering is improvement, I also studied improvement. Students only systematically improve when they have the opportunity, productive strategies, and fair comparisons between prototypes. I then investigate the use of student engineering journals to assess learning from the process of improvement after failure. After discussion, I consider implications from this work as well as future research

  12. Optimum Design and Performance of Porous Concrete for Heavy-Load Traffic Pavement in Cold and Heavy Rainfall Region of NE China

    Directory of Open Access Journals (Sweden)

    Ailing Yao

    2018-01-01

    Full Text Available The aim of the study was to solve the problem of drainage stability of pavement base in cold and Cloudburst area. With porous concrete as the research object, an optimum design of porous concrete was determined using a step filling and orthogonal test method, and the relationship between the porosity and the connected porosity of the porous concrete was analyzed. Furthermore, drainage performance and frost resistance of the pavement, compressive strength of the porous concrete, bending strength, and compressive elastic modulus were studied. The results show that the effects of water-cement ratio on the strength of porous concrete based on the step filling method are the most significant. In addition, the connected porosity and goal porosity have a good linear relationship; that is, the drainage performance increases with the increase in connected porosity, whereas the frost resistance, compressive strength, flexural tensile strength, and compressive elastic modulus decrease with the increase in connected porosity. Based on an engineering project in Inner Mongolia (in China, it was shown that porous concrete with a goal porosity of 15% used as a pavement base could meet the requirements of cold weather, showers, and heavy traffic.

  13. Analysis and evaluation of post construction failures of airport apron ...

    African Journals Online (AJOL)

    A new apron pavement for parking aircrafts was constructed in 2014, but major depressions occurred when used by aircrafts soon after the construction. Failure analysis revealed structural design inconsistent with the United States Federal Aviation Administration Design Code AC 150-5320-6E. The methodologies for the ...

  14. Fatigue and rutting lives in flexible pavement

    Directory of Open Access Journals (Sweden)

    Ahmed Ebrahim Abu El-Maaty Behiry

    2012-12-01

    Full Text Available Flexible pavement is designed based on axle load limits and climatic conditions. The Egyptian code has specified certain load limits that should not be exceeded. The overweight trucks cause severe deterioration to the pavement and thus reduce its life. The study aims at studying the effect of axle load increase, and the variation in pavement modulus, on the overall pavement life. The research uses the BISAR software and the Egyptian environmental and pavement materials conditions to estimate the tensile strains occurring under the asphalt concrete (AC layer and the compressive strains above the subgrade surface. The results revealed that tensile and compressive strain increased with increasing axle loads and decreased with increasing asphalt layer modulus thus the violating trucks should be unloaded when their weights exceed certain limits. Base thickness and subgrade resilient modulus were the key elements which control the equilibrium between fatigue and rutting lives.

  15. Finite element simulation of structural performance on flexible pavements with stabilized base/treated subbase materials under accelerated loading : tech summary.

    Science.gov (United States)

    2011-12-01

    Accelerated pavement testing (APT) has been increasingly used by state highway agencies in recent years for evaluating pavement : design and performance through applying a simulative heavy vehicular load to the pavement section under controlled fi el...

  16. Stresses and strains in pavement structures due to the effect of temperatures

    Directory of Open Access Journals (Sweden)

    Svilar Mila

    2016-01-01

    Full Text Available At its absolute amount, stresses due to the effect of temperature in the pavement structures, especially those rigid, are often of the same order of magnitude as those resulting from vehicles' load, but it happens that due to such impact many slabs become cracked before the road is handed over into operation. The temperature stresses which occur in pavement structures include stresses due to bending and buckling, stresses due to friction and hidden stresses. Stresses caused by the influence of temperature in the pavement structure during the day are generally below the strength of the component materials so they do not cause the consequences for structure. However, appearance of residual stresses and their accumulation after a sufficiently long period of time may lead to failure in structure, i.e. thermal fatigue. The paper presents the effects of temperature changes on the pavement structures in the physical and mechanical terms, and the manner in which the temperature is taken into account during the design of pavement structures.

  17. Triplexer Monitor Design for Failure Detection in FTTH System

    Science.gov (United States)

    Fu, Minglei; Le, Zichun; Hu, Jinhua; Fei, Xia

    2012-09-01

    Triplexer was one of the key components in FTTH systems, which employed an analog overlay channel for video broadcasting in addition to bidirectional digital transmission. To enhance the survivability of triplexer as well as the robustness of FTTH system, a multi-ports device named triplexer monitor was designed and realized, by which failures at triplexer ports can be detected and localized. Triplexer monitor was composed of integrated circuits and its four input ports were connected with the beam splitter whose power division ratio was 95∶5. By means of detecting the sampled optical signal from the beam splitters, triplexer monitor tracked the status of the four ports in triplexer (e.g. 1310 nm, 1490 nm, 1550 nm and com ports). In this paper, the operation scenario of the triplexer monitor with external optical devices was addressed. And the integrated circuit structure of the triplexer monitor was also given. Furthermore, a failure localization algorithm was proposed, which based on the state transition diagram. In order to measure the failure detection and localization time under the circumstance of different failed ports, an experimental test-bed was built. Experiment results showed that the detection time for the failure at 1310 nm port by the triplexer monitor was less than 8.20 ms. For the failure at 1490 nm or 1550 nm port it was less than 8.20 ms and for the failure at com port it was less than 7.20 ms.

  18. Improvement of widening joint design and construction practices for flexible pavements : [summary].

    Science.gov (United States)

    2015-12-01

    Existing roads are widened for several reasons, primarily to respond to increased traffic : volumes or to improve safety. The success of a road widening project depends on many : factors, not least of which are the joint design and construction metho...

  19. Improvement of widening joint design and construction practices for flexible pavements.

    Science.gov (United States)

    2015-09-01

    Few guidelines exist statewide, or even nationwide, for assisting designers in selecting : appropriate roadway widening techniques. Current Florida Department of Transportation : (FDOT) specifications provide a basic framework for widening hot-mix as...

  20. Base Stabilization Guidance and Additive Selection for Pavement Design and Rehabilitation

    Science.gov (United States)

    2017-12-01

    Significant improvements have been made in base stabilization practice that include design specifications and methodology, experience with the selection of stabilizing additives, and equipment for distribution and uniform blending of additives. For t...

  1. Preparation Ferrule Design Effect on Endocrown Failure Resistance.

    Science.gov (United States)

    Einhorn, Michael; DuVall, Nicholas; Wajdowicz, Michael; Brewster, John; Roberts, Howard

    2017-10-06

    bonding found no difference between the groups. Lower instances of catastrophic failure were observed with the endocrown preparations containing 1 mm of preparation ferrule design; however, regardless of the presence of ferrule, this study found that all endocrown restorations suffered a high proportion of catastrophic failures but at loads greater than reported under normal masticatory function. © 2017 by the American College of Prosthodontists.

  2. How to reduce tire-pavement noise : better practices for constructing and texturing concrete pavement surfaces.

    Science.gov (United States)

    2012-08-01

    Concrete pavements can be designed and constructed to be as quiet as any other conventional pavement type in use today. This report : provides an overview of how this can be doneand done consistently. : In order to construct a quieter concrete pav...

  3. Permeable pavement study (Edison)

    Data.gov (United States)

    U.S. Environmental Protection Agency — While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types...

  4. Saw & seal, airport pavement.

    Science.gov (United States)

    2009-05-01

    Due to extreme cold temperatures, hot bituminous pavements on Maines airports are subject to transverse : or thermal cracking. This can lead to poorly performing pavement structure causing heaving and : settlement problems. Studies have shown that...

  5. Pavement Subgrade Performance Study

    DEFF Research Database (Denmark)

    Zhang, Wei; Ullidtz, Per; Macdonald, Robin

    1998-01-01

    The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting...

  6. Quieter pavements guidance document

    Science.gov (United States)

    2013-02-01

    This report provides guidance and better practice recommendations to the National Park : Service for selecting pavement surfaces to minimize tire-pavement noise. The report : contains an overview of common technologies and methods for quieter pavemen...

  7. Concrete pavement joint deterioration.

    Science.gov (United States)

    2015-12-01

    Concrete pavements are an important part of our national infrastructure. In recent years the relatively small number of reported joints deteriorating prematurely in concrete pavements around Indiana has increased. Changes over the past 45 years in IN...

  8. Assessment of low temperature cracking in asphalt pavement mixes and rheological performance of asphalt binders

    Science.gov (United States)

    Sowah-Kuma, David

    Government spends a lot of money on the reconstruction and rehabilitation of road pavements in any given year due to various distresses and eventual failure. Low temperature (thermal) cracking, one of the main types of pavement distress, contributes partly to this economic loss, and comes about as a result of accumulated tensile strains exceeding the threshold tensile strain capacity of the pavement. This pavement distress leads to a drastic reduction of the pavement's service life and performance. In this study, the severity of low temperature (thermal) cracking on road pavements selected across the Province of Ontario and its predicted time to failure was assessed using the AASTHO Mechanistic-Empirical Pavement Design Guide (MEPDG) and AASHTOWARE(TM) software, with inputs such as creep compliance and tensile strength from laboratory test. Highway 400, K1, K2, Y1, Sasobit, Rediset LQ, and Rediset WMX were predicted to have a pavement in-service life above 15 years. Additionally, the rheological performance of the recovered asphalt binders was assessed using Superpave(TM) tests such as the dynamic shear rheometer (DSR) and bending beam rheometer (BBR). Further tests using modified standard protocols such as the extended bending beam rheometer (eBBR) (LS-308) test method and double-edge notched tension (DENT) test (LS-299) were employed to evaluate the failure properties associated with in service performance. The various rheological tests showed K1 to be the least susceptible to low temperature cracking compared to the remaining samples whiles Highway 24 will be highly susceptible to low temperature cracking. X-ray fluorescence (XRF) analysis was performed on the recovered asphalt binders to determine the presence of metals such as zinc (Zn) and molybdenum (Mo) believed to originate from waste engine oil, which is often added to asphalt binders. Finally, the severity of oxidative aging (hardening) of the recovered asphalt binders was also evaluated using the

  9. Designing and Implementation of a Heart Failure Telemonitoring System.

    Science.gov (United States)

    Safdari, Reza; Jafarpour, Maryam; Mokhtaran, Mehrshad; Naderi, Nasim

    2017-09-01

    The aim of this study was to identify patients at-risk, enhancing self-care management of HF patients at home and reduce the disease exacerbations and readmissions. In this research according to standard heart failure guidelines and Semi-structured interviews with 10 heart failure Specialists, a draft heart failure rule set for alerts and patient instructions was developed. Eventually, the clinical champion of the project vetted the rule set. Also we designed a transactional system to enhance monitoring and follow up of CHF patients. With this system, CHF patients are required to measure their physiological measurements (vital signs and body weight) every day and to submit their symptoms using the app. additionally, based on their data, they will receive customized notifications and motivation messages to classify risk of disease exacerbation. The architecture of system comprised of six major components: 1) a patient data collection suite including a mobile app and website; 2) Data Receiver; 3) Database; 4) a Specialists expert Panel; 5) Rule engine classifier; 6) Notifier engine. This system has implemented in Iran for the first time and we are currently in the testing phase with 10 patients to evaluate the technical performance of our system. The developed expert system generates alerts and instructions based on the patient's data and the notify engine notifies responsible nurses and physicians and sometimes patients. Detailed analysis of those results will be reported in a future report. This study is based on the design of a telemonitoring system for heart failure self-care that intents to overcome the gap that occurs when patients discharge from the hospital and tries to accurate requirement of readmission. A rule set for classifying and resulting automated alerts and patient instructions for heart failure telemonitoring was developed. It also facilitates daily communication among patients and heart failure clinicians so any deterioration in health could be

  10. Failure Probability of Three Designs of Zirconia Crowns.

    Science.gov (United States)

    Ramos, Gabriela Freitas; Monteiro, Evelyn Barbosa; Bottino, Marco Antonio; Zhang, Yu; Marques de Melo, Renata

    2015-01-01

    This study used a two-parameter Weibull analysis for evaluation of the lifespan of fully or partially porcelain-/glaze-veneered zirconia crowns after fatigue test. A sample of 60 first molars were selected and prepared for full-coverage crowns with three different designs (n = 20): traditional (crowns with zirconia framework covered with feldspathic porcelain), modified (crowns partially covered with veneering porcelain), and monolithic (full-contour zirconia crowns). All specimens were treated with a glaze layer. Specimens were subjected to mechanical cycling (100 N, 3 Hz) with a piston with a hemispherical tip (Ø = 6 mm) until the specimens failed or up to 2 × 10⁶ cycles. Every 500,000 cycles, the fatigue tests were interrupted and stereomicroscopy (10×) was used to inspect the specimens for damage. The authors performed Weibull analysis of interval data to calculate the number of failures in each interval. The types and numbers of failures according to the groups were: cracking (13 traditional, 6 modified) and chipping (4 traditional) of the feldspathic porcelain, followed by delamination (1 traditional) at the veneer/core interface and debonding (2 monolithic) at the cementation interface. Weibull parameters (β, scale; η, shape), with a two-sided confidence interval of 95%, were: traditional-1.25 and 0.9 × 10⁶ cycles; modified-0.58 and 11.7 × 10⁶ cycles; and monolithic-1.05 and 16.5 × 10⁶ cycles. Traditional crowns showed greater susceptibility to fatigue, the modified group presented higher propensity to early failures, and the monolithic group showed no susceptibility to fatigue. The modified and monolithic groups presented the highest number of crowns with no failures after the fatigue test. The three crown designs presented significantly different behaviors under fatigue. The modified and monolithic groups presented less probability of failure after 2 × 10⁶ cycles.

  11. Failure probability of three designs of zirconia crowns

    Science.gov (United States)

    Ramos, G. Freitas; Monteiro, E. Barbosa Carmona; Bottino, M.A.; Zhang, Y.; de Melo, R. Marques

    2015-01-01

    Objectives This study utilized a 2-parameter Weibull analysis for evaluation of lifetime of fully or partially porcelain-/glaze-veneered zirconia crowns after fatigue test. Methods Sixty first molars were selected and prepared for full-coverage crowns with three different designs(n = 20): Traditional –crowns with zirconia framework covered with feldspathic porcelain; Modified– crowns partially covered with veneering porcelain; and Monolithic–full-contour zirconia crowns. All specimens were treated with a glaze layer. Specimens were subjected to mechanical cycling (100N, 3Hz) with a piston with hemispherical tip (Ø=6 mm) until the specimens failed or up to 2×106 cycles. Every 500,000 cycles intervals, the fatigue tests were interrupted, and stereomicroscopy (10 X) was used to inspect the specimens for damage. We performed Weibull analysis of interval data to calculate the number of failures in each interval. Results The types and number of failures according to the groups were: cracking (Traditional-13, Modified-6) and chipping (Traditional-4) of the feldspathic porcelain, followed by delamination (Traditional-1) at the veneer/core interface and debonding (Monollithic-2) at the cementation interface. Weibull parameters (beta, scale; and eta, shape), with a two-sided confidence interval of 95%, were: Traditional – 1.25 and 0.9 × 106cycles; Modified– 0.58 and 11.7 × 106 cycles; and Monolithic – 1.05 and 16.5 × 106 cycles. Traditional crowns showed greater susceptibility to fatigue, the Modified group presented higher propensity to early failures, and the Monolithic group showed no susceptibility to fatigue. The Modified and Monolithic groups presented the highest number of crowns with no failures after the fatigue test. Conclusions The three crown designs presented significantly different behaviors under fatigue. The Modified and the Monolithic groups presented less probability to failure after 2×106cycles. PMID:26509988

  12. Quantifying Evaporation in a Permeable Pavement System ...

    Science.gov (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. The U.S. Environmental Protection Agency (USEPA) constructed a 0.4-ha parking lot in Edison, NJ, that incorporated three different permeable pavement types in the parking lanes – permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). An impermeable liner installed 0.4 m below the driving surface in four 11.6-m by 4.74-m sections per each pavement type captures all infiltrating water and routes it to collection tanks that can contain events up to 38 mm. Each section has a design impervious area to permeable pavement area ratio of 0.66:1. Pressure transducers installed in the underdrain collection tanks measured water level for 24 months. Level was converted to volume using depth-to-volume ratios for individual collection tanks. Using a water balance approach, the measured infiltrate volume was compared to rainfall volume on an event-basis to determine the rainfall retained in the pavement strata and underlying aggregate. Evaporation since the previous event created additional storage in the pavement and aggregate layers. Events were divided into three groups based on antecedent dry period (ADP) and three, four-month categories of potential e

  13. Feasibility of perpetual pavement stage construction in China: A life cycle cost analysis

    Directory of Open Access Journals (Sweden)

    Zhongyin Guo

    2016-12-01

    Full Text Available The main objective of pavement design and management is to build sustainable pavement structure with minimum costs during its whole life. There are many uncertainties in the process of pavement design pertaining many of its variables, such as future traffic estimation, long time behavior of materials, future weights and types of traveling vehicles, availability of funds etc. Therefore, it is important to apply pavement stage construction technique during the process of pavement design and management to minimize the risk associated with these uncertainties. From the beginning of 2000, the research and application of perpetual asphalt pavement (PP technology has been deployed in China. The semi rigid base for asphalt pavement has been normally considered as typical component of high class highways in the design according to the Chinese experience since 1997. The research objective is to apply pavement stage construction for the evaluation of life cycle costs of Chinese perpetual and traditional semi rigid pavements using operational pavement management system in addition to examine its suitability for design and construction of more economical and durable flexible pavements. It has been found that the stage construction of asphalt layers in PP over semi rigid pavement foundation will create more sustainable and trusted pavement structures in spite of 2–5% increase in present total cost.

  14. Winter tenting of highway pavements : test program and discussion of causes and mechanisms

    Science.gov (United States)

    2000-10-28

    Tenting consists of localized frost heaving in the immediate vicinity of transverse pavement cracks. It produces a highly irregular riding : surface, leads to premature pavement-surface deterioration, occurs on highways designed for high traffic volu...

  15. Effect of Michigan multi-axle trucks on pavement distress and profile: volume 2.

    Science.gov (United States)

    2009-02-01

    With the adoption of the new mechanistic-empirical pavement design method and the employment of axle load spectra, the question of evaluating the pavement damage resulting from different axle and truck configurations has become more relevant. In part...

  16. Effect of Michigan multi-axle trucks on pavement distress and profile: volume 3.

    Science.gov (United States)

    2009-02-01

    With the adoption of the new mechanistic-empirical pavement design method and the employment of axle load : spectra, the question of evaluating the pavement damage resulting from different axle and truck configurations has : become more relevant. In ...

  17. Effect of Michigan multi-axle trucks on pavement distress and profile : volume 1.

    Science.gov (United States)

    2009-02-01

    With the adoption of the new mechanistic-empirical pavement design method and the employment of axle load : spectra, the question of evaluating the pavement damage resulting from different axle and truck configurations has : become more relevant. In ...

  18. Congestive Heart Failure Cardiopoietic Regenerative Therapy (CHART-1) trial design.

    Science.gov (United States)

    Bartunek, Jozef; Davison, Beth; Sherman, Warren; Povsic, Thomas; Henry, Timothy D; Gersh, Bernard; Metra, Marco; Filippatos, Gerasimos; Hajjar, Roger; Behfar, Atta; Homsy, Christian; Cotter, Gad; Wijns, William; Tendera, Michal; Terzic, Andre

    2016-02-01

    Cardiopoiesis is a conditioning programme that aims to upgrade the cardioregenerative aptitude of patient-derived stem cells through lineage specification. Cardiopoietic stem cells tested initially for feasibility and safety exhibited signs of clinical benefit in patients with ischaemic heart failure (HF) warranting definitive evaluation. Accordingly, CHART-1 is designed as a large randomized, sham-controlled multicentre study aimed to validate cardiopoietic stem cell therapy. Patients (n = 240) with chronic HF secondary to ischaemic heart disease, reduced LVEF (Heart Failure Questionnaire score, 6 min walk test, LV end-systolic volume, and LVEF at 9 months. The secondary efficacy endpoint is the time to cardiovascular death or worsening HF at 12 months. Safety endpoints include mortality, readmissions, aborted sudden deaths, and serious adverse events at 12 and 24 months. The CHART-1 clinical trial is powered to examine the therapeutic impact of lineage-directed stem cells as a strategy to achieve cardiac regeneration in HF populations. On completion, CHART-1 will offer a definitive evaluation of the efficacy and safety of cardiopoietic stem cells in the treatment of chronic ischaemic HF. NCT01768702. © 2015 The Authors European Journal of Heart Failure © 2015 European Society of Cardiology.

  19. Evaluating the performance of sustainable perpetual pavements using recycled asphalt pavement in China

    Directory of Open Access Journals (Sweden)

    Saud A. Sultan

    2016-10-01

    Full Text Available The vast highways network in China is moving from the phase of construction to the phase of maintenance, and with the introduction of new technique of perpetual pavement in last decade, it is necessary to consider recycling as one of the promising solutions for rehabilitation of old asphalt concrete pavement and ultimately to convert them into perpetual pavements. The aim is to reuse the existing pavement materials for several reasons, mainly to preserve natural resources such as aggregates, and to satisfy economic requirements by reducing the cost of highway construction and rehabilitation. A detailed testing program has been carried out on recycled asphalt pavements materials (RAP to evaluate their mechanical and structural characteristics to be used for the construction and rehabilitation of road pavements. Different types of RAP mixes have been stabilized by Portland cement to find the most suitable one from the point of view of design, construction, economy and environment. The analysis of life cycle costs has been carried out using system analysis and management of pavement program (SAMP5. The analysis of life cycle costs showed that the use of Portland cements with small percentages improves the structural characteristics of recycled asphalt materials to be used as stabilized base pavement layers for new or rehabilitated old road pavements and also for the construction and rehabilitation of perpetual pavements. A large amount of savings in construction and rehabilitation cost has been achieved by the use of stabilized RAP materials in addition to important contributions to the environment and preserving of natural resources.

  20. 3D Tyre/Road pavement contact stress measurements

    CSIR Research Space (South Africa)

    De Beer, Morris

    2010-10-01

    Full Text Available The CSIR’s proprietary Stress-in-Motion (SIM) measurements provide rational descriptions of 1D, 2D and 3D tyre/road pavement stresses for: Road pavement design testing and evaluation, as well as tyre design, testing and evaluation....

  1. Pavement Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Comprehensive Environmental and Structural AnalysesThe ERDC Pavement Testing Facility, located on the ERDC Vicksburg campus, was originally constructed to provide an...

  2. Investigation of Primary Causes of Load-Related Cracking in Asphalt Concrete Pavement in North Carolina

    Science.gov (United States)

    Park, Hong Joon

    This dissertation presents causes of cracking in asphalt concrete pavement in North Carolina through field investigation and laboratory experiments with field extracted material. North Carolina is experiencing higher than anticipated rates of fatigue cracking compared to other state. These higher than expected rates could be reflective of the national trends in mix design practice or could be caused by structural pavement failures. The problems associated with premature cracking in North Carolina pavements point to the need to evaluate the North Carolina Department of Transportation (NCDOT) mixes, processes, and measures to ensure that these factors properly balance the goals of preventing cracking and minimizing permanent deformation. Without solid data from in-service pavements, any conclusions regarding the causes of these failures might be pure conjecture. Accordingly, this research examines material properties through laboratory experiments using field-extracted materials and investigates in situ pavements and pavement structure. In order to assess condition of existing pavement, alligator cracking index (ACI) was developed. The asphalt content in the top layer that exhibits top-down cracking or bottom-up cracking has a proportional relationship to ACI values. The air void content in a bottom layer that exhibits top-down cracking or bottom-up cracking shows an inverse proportional relationship to ACI values. These observations reflect reasonable results. A comparison between ACI and asphalt film thickness values does not produce noteworthy findings, but somewhat reasonable results are evident once the range of comparison is narrowed down. Thicker film thicknesses show higher ACI values. From field core visual observations, road widening is identified as a major cause of longitudinal cracking. Regions with observed layer interface separation tend to have low ACI values. Through tensile strain simulation based on actual field conditions, it is observed that

  3. Fusing complementary images for pavement cracking measurements

    International Nuclear Information System (INIS)

    Yao, Ming; Zhao, Zuyun; Xu, Bugao; Yao, Xun

    2015-01-01

    Cracking is a major pavement distress that jeopardizes road serviceability and traffic safety. Automated pavement distress survey (APDS) systems have been developed using digital imaging technology to replace human surveys for more timely and accurate inspections. Most APDS systems require special lighting devices to illuminate pavements and prevent shadows of roadside objects that distort cracks in the image. Most artificial lighting devices are laser based, and are either hazardous to unprotected people or require dedicated power supplies on the vehicle. This study was aimed to develop a new imaging system that can scan pavement surface at highway speed and determine the level of severity of pavement cracking without using any artificial lighting. The new system consists of dual line-scan cameras that are installed side by side to scan the same pavement area as the vehicle moves. Cameras are controlled with different exposure settings so that both sunlit and shadowed areas can be visible in two separate images. The paired images contain complementary details useful for reconstructing an image in which the shadows are eliminated. This paper intends to present (1) the design of the dual line-scan camera system, (2) a new calibration method for line-scan cameras to rectify and register paired images, (3) a customized image-fusion algorithm that merges the multi-exposure images into one shadow-free image for crack detection, and (4) the results of the field tests on a selected road over a long period. (paper)

  4. Diseño de losas de hormigón con geometría optimizada Design of concrete pavement with optimized slab geometry

    Directory of Open Access Journals (Sweden)

    Juan Pablo Covarrubias V.

    2012-12-01

    condiciones de cargas mecánicas y térmicas en diferentes posiciones. El agrietamiento de las losas se determina calculando la fatiga del hormigón y los modelos utilizados por la guía de diseño AASHTO del año 2007 y mediante calibración en secciones de prueba a gran escala. La nueva metodología diseña losas de hormigón que en promedio son 7 cm más delgadas para vías de alto tráfico en relación con el diseño tradicional de pavimentos AASHTO (1993. El método de diseño también es capaz de diseñar de manera eficiente pavimentos de hormigón para vías de menor volumen de tráfico que no son cubiertos con los actuales métodos de diseño de pavimento dando una alternativa a soluciones en asfalto.A new technology has been developed to design concrete pavements, which reduces slabs' thickness and optimizes their sizes, because of trucks axles' geometry. The design is supported by a gravel base treated with concrete or asphalt. It assumes there is no adherence between the base (existing pavement and the concrete slab. The core principle of this design method consists of designing a slab size, so that no more than one wheel set stays on a given slab, thus minimizing the critical tensile stress on the surface. Test segments have been built on a large scale and they have been tested under accelerated loads, with concrete thickness of 8, 15 and 20 cm, all of them having a gravel base and non-adhered asphaltic layers. Tests demonstrated that a reduced-size slab, of low thickness, might bear a considerable amount of equivalent axles before cracking takes place. Concrete slabs on gravel bases with 20 cm thickness did not suffer from cracking, in spite of being tested under more than 50 millions of equivalent axles. Slabs of 15 cm thickness suffered from cracking when tested under an average of 12 millions equivalent axles, while slabs of 8 cm thickness endured 75,000 equivalent axles before the first cracking took place. Besides the executed tests demonstrated that fiber

  5. The application of permeable pavement with emphasis on successful design, water quality benefits, and identification of knowledge and data gaps : a summary report from the National Center for Sustainable Transportation.

    Science.gov (United States)

    2015-06-01

    Permeable pavement presented in this paper is defined as a type of pavement that has ability : to store stormwater until it infiltrates through the subgrade soil and can function as a : conventional pavement to carry specific traffic load and speed. ...

  6. Portland cement concrete pavement best practices summary report.

    Science.gov (United States)

    2010-08-01

    This report summarizes the work and findings from WA-RD 744. This work consisted of four separate efforts related to best practices for portland cement concrete (PCC) pavement design and construction: (1) a review of past and current PCC pavement, (2...

  7. Assessing Asphalt and Concrete Pavement Surface Texture in the Field

    Directory of Open Access Journals (Sweden)

    Saad I. Sarsam

    2016-06-01

    Full Text Available The incorporation of safety characteristics into the traditional pavement structural design or in the functional evaluation of pavement condition has not been established yet. The design has focused on the structural capacity of the roadway so that the pavement can withstand specific level of repetitive loading over the design life. On the other hand, the surface texture condition was neither included in the AASHTO design procedure nor in the present serviceability index measurements. The pavement surface course should provide adequate levels of friction and ride quality and maintain low levels of noise and roughness. Many transportation departments perform routine skid resistant testing, the type of equipment used for testing varies depending on the preference of each transportation department. It was felt that modeling of the surface texture condition using different methods of testing may assist in solving such problem. In this work, Macro texture and Micro texture of asphalt and cement concrete pavement surface have been investigated in the field using four different methods (The Sand Patch Method, Outflow Time Method, British Pendulum Tester and Photogrammetry Technique. Two different grain sizes of sand have been utilized in conducting the Sand Patch while the Micro texture was investigated using the British Pendulum tester method at wet pavement surface conditions. The test results of the four methods were correlated to the skid number. It was concluded that such modeling could provide instant data in the field for pavement condition which may help in pavement maintenance management.

  8. Rock Failure Criteria for Design of Underground Structural Supports.

    Science.gov (United States)

    1985-09-01

    UNDERGROUND STRUCTURAL SUPPORTS PART I: INTRODUCTION Background Failure Criteria Bieniawski (1984) defines a criterion of failure as "an algebraic expres...of load, deformation, stress, strain, or other parameters." Bieniawski listed no less than fourteen failure criteria that have been used in the past...failure. Bieniawski (1984) is of the opinion that to meet the immediate needs of the practical rock engineer, attention should be directed to empiri- cal

  9. Defense against common-mode failures in protection system design

    International Nuclear Information System (INIS)

    Wyman, R.H.; Johnson, G.L.

    1998-01-01

    The introduction of digital instrumentation and control into reactor safety systems creates a heightened concern about common-mode failure. This paper discusses the concern and methods of cope with the concern. Common-mode failures have been a 'fact-of-life' in existing systems. The informal introduction of defense-in-depth and diversity (D-in-D and D) - coupled with the fact that hardware common-mode failures are often distributed in time - has allowed systems to deal with past common-mode failures. However, identical software operating in identical redundant systems presents the potential for simultaneous failure. Consequently, the use of digital systems raises the concern about common-mode failure to a new level. A more methodical approach to mitigating common-mode failure is needed to address these concerns. Purposeful introduction of D-in-D and D has been used as a defense against common-mode failure in reactor protection systems. At least two diverse systems are provided to mitigate any potential initiating event. Additionally, diverse displays and controls are provided to allow the operator to monitor plant status and manually initiate engineered safety features. A special form of common-mode failure analysis called 'defense-in-depth and diversity analysis' has been developed to identify possible common-mode failure vulnerabilities in digital systems. An overview of this analysis technique is provided. (author)

  10. Defense against common-mode failures in protection system design

    International Nuclear Information System (INIS)

    Wyman, R.H.; Johnson, G.L.

    1997-01-01

    The introduction of digital instrumentation and control into reactor safety systems creates a heightened concern about common-mode failure. This paper discusses the concern and methods to cope with the concern. Common-mode failures have been a ''fact-of-life'' in existing systems. The informal introduction of defense-in-depth and diversity (D-in-D ampersand D)-coupled with the fact that hardware common-mode failures are often distributed in time-has allowed systems to deal with past common-mode failures. However, identical software operating in identical redundant systems presents the potential for simultaneous failure. Consequently, the use of digital systems raises the concern about common-mode failure to a new level. A more methodical approach to mitigating common-mode failure is needed to address these concerns. Purposeful introduction of D-in-D ampersand D has been used as a defense against common-mode failure in reactor protection systems. At least two diverse systems are provided to mitigate any potential initiating event. Additionally, diverse displays and controls are provided to allow the operator to monitor plant status and manually initiate engineered safety features. A special form of conimon-mode failure analysis called ''defense-in-depth and diversity analysis'' has been developed to identify possible conimon-mode failure vulnerabilities in digital systems. An overview of this analysis technique is provided

  11. Sustainable Mitigation of Stormwater Runoff Through Fully Permeable Pavement

    Science.gov (United States)

    2018-03-01

    This report presents the implementation of new design method developed using mechanistic-empirical design approach by University of California Pavement Research Center (UCPRC) through building two test sections at California State University Long Bea...

  12. Integrate System Modeling for Design and Production Planning of High Quality Products Considering Failure Data

    Science.gov (United States)

    Aoyama, Kazuhiro; Koga, Tsuyoshi

    2009-07-01

    Since the product recall problem is recently observed, realizing design and production activities that can prevent occurrences of a product failure has been becoming a serious issue. This paper proposes "the Synthetic design approach of a product and a production process which enables to reduce occurrences of a product failure from the initial stage of a product development." In order to realize this proposed concept as a specific system, the integrated model of the failure information in the design and production is introduced. This paper shows some examples of design and production for a circuit breaker and an automobile with considering a design error and a production failure using developed prototype system.

  13. Evaluation of long-term pavement performance and noise characteristics of open-graded friction courses : project 2.

    Science.gov (United States)

    2012-06-01

    This report describes the second of three experimental installations of open-graded friction course (OGFC) quieter pavements designed to reduce the noise generated at the tire/pavement interface. Experimental sections of OGFC were built using a...

  14. Guidelines for detection, analysis, and treatment of materials-related distress in concrete pavements. Volume 2, Guidelines description and use

    Science.gov (United States)

    2002-08-01

    The performance of concrete pavements can be adversely affected by the concrete's inability to resist the environment in which it is placed. This lack of durability can occur even when the structural design of the pavement is adequate. The distresses...

  15. Pavement structure mechanics response of flexible on semi-flexible overlay that based on the old cement concrete pavement damage

    Directory of Open Access Journals (Sweden)

    Jiang Ruinan

    2015-01-01

    Full Text Available The old cement pavement damage status directly affect the design of the paving renovation. Based on the state of the old road investigation, combined with the research data at home and abroad, use the control index that average deflection, deflection value and CBR value to determine the reasonable time to overlay. Draw up the typical pavement structure according to the principle of combination of old cement pavement overlay structure design, and calculated that the tensile stress and shear stress in asphalt layer ,semi-flexible layer and the tensile in the old cement pavement adopting BISA3.0 statics finite element analysis model when modulus in the old road was diminishing. Use the computed result to analyses the influence of old road damage condition the influence of pavement structure.

  16. Precast concrete pavement - systems and performance review

    Science.gov (United States)

    Novak, Josef; Kohoutková, Alena; Křístek, Vladimír; Vodička, Jan

    2017-09-01

    Long-term traffic restrictions belong to the key disadvantages of conventional cast-in-plane concrete pavements which have been used for technical structures such as roads, parking place and airfield pavements. As a consequence, the pressure is put on the development of such systems which have short construction time, low production costs, long-term durability, low maintenance requirements etc.. The paper presents the first step in the development of an entirely new precast concrete pavement (PCP) system applicable to airfield and highway pavements. The main objective of the review of PCP systems is to acquire a better understanding of the current systems and design methods used for transport infrastructure. There is lack of information on using PCP systems for the construction of entirely new pavements. To most extensive experience is dated back to the 20th century when hexagonal slab panels and system PAG were used in the Soviet Union for the military airfields. Since cast-in-situ pavements became more common, the systems based on precast concrete panels have been mainly utilized for the removal of damaged sections of existing structures including roads, highways etc.. Namely, it concerns Fort Miller Super Slab system, Michigan system, Uretek Stitch system and Kwik system. The presented review indicates several issues associated with the listed PCP systems and their applications to the repair and rehabilitation of existing structures. Among others, the type of manufacturing technology, particularly the position of slots for dowel bars, affects the durability and performance of the systems. Gathered information serve for the development of a new system for airfield and highway pavement construction.

  17. Filter design for failure detection and isolation in the presence of modeling errors and disturbances

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    1996-01-01

    The design problem of filters for robust failure detection and isolation, (FDI) is addressed in this paper. The failure detection problem will be considered with respect to both modeling errors and disturbances. Both an approach based on failure detection observers as well as an approach based on...

  18. Advanced composites: Design and application. Proceedings of the meeting of the Mechanical Failures Prevention Group

    Science.gov (United States)

    Shives, T. R.; Willard, W. A.

    1979-01-01

    The design and application of advanced composites is discussed with emphasis on aerospace, aircraft, automotive, marine, and industrial applications. Failure modes in advanced composites are also discussed.

  19. State-of-the-Art Review on Sustainable Design and Construction of Quieter Pavements—Part 2: Factors Affecting Tire-Pavement Noise and Prediction Models

    Directory of Open Access Journals (Sweden)

    Okan Sirin

    2016-07-01

    Full Text Available Traffic noise is a combination of noises produced from a number of sources. Of all the traffic noise sources, tire-pavement noise, which is emitted as a result of the interaction of rolling, slipping, or dragging tires and the pavement surface, is the dominant contributor of overall noise, particularly when vehicles are moving at higher speeds. Therefore, a number of research studies have been conducted to identify and analyze the factors affecting the generation of tire-pavement interaction noise. This helps in identifying and selecting appropriate noise mitigation techniques. In this paper, an extensive literature survey on the factors affecting tire-pavement noise is presented, and different views on the impact of each individual factor are discussed. From the literature survey, it is also evident that there is a potential correlation between pavement’s material characteristics and tire-pavement noise. A comprehensive discussion about this correlation is presented in the paper. In addition, this paper discusses various mathematical models for predicting pavement noise, and their advantages and shortcomings.

  20. Failure modes and materials design for biomechanical layer structures

    Science.gov (United States)

    Deng, Yan

    Ceramic materials are finding increasing usage in the area of biomechanical replacements---dental crowns, hip and bone implants, etc.---where strength, wear resistance, biocompatibility, chemical durability and even aesthetics are critical issues. Aesthetic ceramic crowns have been widely used in dentistry to replace damaged or missing teeth. However, the failure rates of ceramic crowns, especially all-ceramic crowns, can be 1%˜6% per year, which is not satisfactory to patients. The materials limitations and underlying fracture mechanisms of these prostheses are not well understood. In this thesis, fundamental fracture and damage mechanisms in model dental bilayer and trilayer structures are studied. Principle failure modes are identified from in situ experimentation and confirmed by fracture mechanics analysis. In bilayer structures of ceramic/polycarbonate (representative of ceramic crown/dentin structure), three major damage sources are identified: (i) top-surface cone cracks or (ii) quasiplasticity, dominating in thick ceramic bilayers; (iii) bottom-surface radial cracks, dominating in thin ceramic bilayers. Critical load P for each damage mode are measured in six dental ceramics: Y-TZP zirconia, glass-infiltrated zirconia and alumina (InCeram), glass-ceramic (Empress II), Porcelain (Mark II and Empress) bonded to polymer substrates, as a function of ceramic thickness d in the range of 100 mum to 10 mm. P is found independent of d for mode (i) and (ii), but has a d 2 relations for mode (iii)---bottom surface radial cracking. In trilayer structures of glass/core-ceramic/polycarbonate (representing veneer porcelain/core/dentin structures), three inner fracture origins are identified: radial cracks from the bottom surface in the (i) first and (ii) second layers; and (iii) quasiplasticity in core-ceramic layer. The role of relative veneer/core thickness, d1/d 2 and materials properties is investigated for three core materials with different modulus (114--270GPa

  1. Designing to Mitigate Food Growing Failures in Space

    Science.gov (United States)

    Jones, Harry

    2004-01-01

    Future space life support systems may use crop plants to grow most of the crew s food. A harvest failure can reduce the food available for future consumption. If the previously stored food is insufficient to reach the next harvest, the crew may go hungry. This paper considers how the overall food supply system should be modified to cope with food production failures. The food supply concept for a mission will use grown food, or stored food, cIr both. The optimum food supply mix depends on the costs and failure probabilities of stored and grown food. A simple food system model assumes that either we obtain the nominal harvest or a failure occurs and no food is harvested. Given the probability that any particular harvest fails, it is easy to compute the expected number of failures and the total food shortfall over a mission. If some food is grown and the probability of harvest failure is high, a non-redundant system has an unacceptable likelihood that the crew will have no food for a full harvest period. Food supply reliability must be increased either by supplying more food initially or by increasing food production capacity. We can obtain a very reliable food supply even when the harvest failure rate is high. If the cost of growing food is much less than the cost of providing stored food, it is better to provide redundant food growing capacity than to increase initial storage. A more realistic biomass production failure model allows the harvest amount or time to vary around the nominal values, using stochastic modeling with repeated Monte Carlo simulation, but such failures have minor impact compared to a complete harvest failure.

  2. Pervious Pavement System Evaluation

    Science.gov (United States)

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, grade...

  3. Desert Pavement Studies

    National Research Council Canada - National Science Library

    Haff, Peter

    2003-01-01

    Combining plan view information from aerial photography showing details of stream channels on desert pavement surfaces with process-based erosion models, a high-resolution, synthetic topography DEM...

  4. Rutting Prediction in Asphalt Pavement Based on Viscoelastic Theory

    Directory of Open Access Journals (Sweden)

    Nahi Mohammed Hadi

    2016-01-01

    Full Text Available Rutting is one of the most disturbing failures on the asphalt roads due to the interrupting it is caused to the drivers. Predicting of asphalt pavement rutting is essential tool leads to better asphalt mixture design. This work describes a method of predicting the behaviour of various asphalt pavement mixes and linking these to an accelerated performance testing. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating the laboratory testing of asphalt mixes in Hamburg Wheel Rut Tester (HWRT for rutting. The creep parameters C1, C2 and C3 are developed from the triaxial repeated load creep test at 50°C and at a frequency of 1 Hz and the modulus of elasticity and Poisson’ s ratio determined at the same temperature. Viscoelastic model (creep model is adopted using a FE simulator (ANSYS in order to calculate the rutting for various mixes under a uniform loading pressure of 500 kPa. An eight-node with a three Degrees of Freedom (UX, UY, and UZ Element is used for the simulation. The creep model developed for HWRT tester was verified by comparing the predicted rut depths with the measured one and by comparing the rut depth with ABAQUS result from literature. Reasonable agreement can be obtained between the predicted rut depths and the measured one. Moreover, it is found that creep model parameter C1 and C3 have a strong relationship with rutting. It was clear that the parameter C1 strongly influences rutting than the parameter C3. Finally, it can be concluded that creep model based on finite element method can be used as an effective tool to analyse rutting of asphalt pavements.

  5. Permeable pavement study (Edison)

    Science.gov (United States)

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable interlocking concrete pavement (PICP), pervious concrete (PC), and porous asphalt (PA). Each permeable pavement type has four, 54.9-m2, lined sections that direct all infiltrate into 5.7-m3 tanks enabling complete volume collection and sampling. This paper highlights the results from a 12-month period when samples were collected from 13 rainfall/runoff events and analyzed for nitrogen species, orthophosphate, and organic carbon. Differences in infiltrate concentrations among the three permeable pavement types were assessed and compared with concentrations in rainwater samples and impervious asphalt runoff samples, which were collected as controls. Contrary to expectations based on the literature, the PA infiltrate had significantly larger total nitrogen (TN) concentrations than runoff and infiltrate from the other two permeable pavement types, indicating that nitrogen leached from materials in the PA strata. There was no significant difference in TN concentration between runoff and infiltrate from either PICP or PC, but TN in runoff was significantly larger than in the rainwater, suggesting meaningful inter-event dry de

  6. Flexible pavement rehabilitation using pulverization.

    Science.gov (United States)

    2008-06-01

    Pulverization is a roadway rehabilitation strategy that involves in-place recycling of the entire existing flexible pavement layer and some of the existing granular base layer (Figure 1). Pavement pulverization provides an alternative to conventional...

  7. Puzzles in modern biology. I. Male sterility, failure reveals design [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Steven A. Frank

    2016-09-01

    Full Text Available Many human males produce dysfunctional sperm. Various plants frequently abort pollen. Hybrid matings often produce sterile males. Widespread male sterility is puzzling. Natural selection prunes reproductive failure. Puzzling failure implies something that we do not understand about how organisms are designed. Solving the puzzle reveals the hidden processes of design.

  8. Reliability Based Optimal Design of Vertical Breakwaters Modelled as a Series System Failure

    DEFF Research Database (Denmark)

    Christiani, E.; Burcharth, H. F.; Sørensen, John Dalsgaard

    1996-01-01

    Reliability based design of monolithic vertical breakwaters is considered. Probabilistic models of important failure modes such as sliding and rupture failure in the rubble mound and the subsoil are described. Characterisation of the relevant stochastic parameters are presented, and relevant design...... variables are identified and an optimal system reliability formulation is presented. An illustrative example is given....

  9. State of the art in power cable design, failure mechanisms and testing

    International Nuclear Information System (INIS)

    Orton, H.

    2005-01-01

    This presentation describes state of the art in power cable design, failure mechanisms and testing. It gives a history of cable usage and design of cables, describes different cable types, assessment of the condition of cables, aging and failures, testing and diagnostics

  10. Increased costs to US pavement infrastructure from future temperature rise

    Science.gov (United States)

    Underwood, B. Shane; Guido, Zack; Gudipudi, Padmini; Feinberg, Yarden

    2017-10-01

    Roadway design aims to maximize functionality, safety, and longevity. The materials used for construction, however, are often selected on the assumption of a stationary climate. Anthropogenic climate change may therefore result in rapid infrastructure failure and, consequently, increased maintenance costs, particularly for paved roads where temperature is a key determinant for material selection. Here, we examine the economic costs of projected temperature changes on asphalt roads across the contiguous United States using an ensemble of 19 global climate models forced with RCP 4.5 and 8.5 scenarios. Over the past 20 years, stationary assumptions have resulted in incorrect material selection for 35% of 799 observed locations. With warming temperatures, maintaining the standard practice for material selection is estimated to add approximately US$13.6, US$19.0 and US$21.8 billion to pavement costs by 2010, 2040 and 2070 under RCP4.5, respectively, increasing to US$14.5, US$26.3 and US$35.8 for RCP8.5. These costs will disproportionately affect local municipalities that have fewer resources to mitigate impacts. Failing to update engineering standards of practice in light of climate change therefore significantly threatens pavement infrastructure in the United States.

  11. Mobile geographic information system (GIS) solution for pavement condition surveys.

    Science.gov (United States)

    2012-06-28

    This report discusses the design and implementation of a software-based solution that will improve the data collection processes during the Pavement Condition Surveys (PCS) conducted by the State Materials Office (SMO) of the Florida Department of Tr...

  12. Project Level Performance Database for Rigid Pavements in Texas, II

    Science.gov (United States)

    2011-08-01

    Over the years, the Texas Department of Transportation (TxDOT) has built a number of CRCP (continuously reinforced : concrete pavement) experimental sections to investigate the effects of design, materials, and construction variables on CRCP : struct...

  13. Permeable pavement research – Edison, New Jersey

    Science.gov (United States)

    These are the slides for the New York City Concrete Promotional Council Pervious Concrete Seminar presentation. The basis for the project, the monitoring design and some preliminary monitoring data from the permeable pavement parking lot at the Edison Environmental Center are pre...

  14. Numerical Study of Tire Hydroplaning Based on Power Spectrum of Asphalt Pavement and Kinetic Friction Coefficient

    Directory of Open Access Journals (Sweden)

    Shengze Zhu

    2017-01-01

    Full Text Available Hydroplaning is a driving phenomenon threating vehicle’s control stability and safety. It happens when tire rolls on wet pavement with high speed that hydrodynamic force uplifts the tire. Accurate numerical simulation to reveal the mechanism of hydroplaning and evaluate the function of relevant factors in this process is significant. In order to describe the friction behaviors of tire-pavement interaction, kinetic friction coefficient curve of tire rubber and asphalt pavement was obtained by combining pavement surface power spectrum and complex modulus of tread rubber through Persson’s friction theory. Finite element model of tire-fluid-pavement was established in ABAQUS, which was composed of a 225-40-R18 radial tire and three types of asphalt pavement covered with water film. Mechanical responses and physical behaviors of tire-pavement interaction were observed and compared with NASA equation to validate the applicability and accuracy of this model. Then contact force at tire-pavement interface and critical hydroplaning speed influenced by tire inflation pressure, water film thickness, and pavement types were investigated. The results show higher tire inflation pressure, thinner water film, and more abundant macrotexture enhancing hydroplaning speed. The results could be applied to predict hydroplaning speed on different asphalt pavement and improve pavement skid resistance design.

  15. Development of Enhanced Pavement Deterioration Curves

    OpenAIRE

    Ercisli, Safak

    2015-01-01

    Modeling pavement deterioration and predicting the pavement performance is crucial for optimum pavement network management. Currently only a few models exist that incorporate the structural capacity of the pavements into deterioration modeling. This thesis develops pavement deterioration models that take into account, along with the age of the pavement, the pavement structural condition expressed in terms of the Modified Structural Index (MSI). The research found MSI to be a significant input...

  16. A Method for Analyzing Effects of Dam Failures in Design Studies.

    Science.gov (United States)

    1972-08-01

    THOMAS UNCLASSIFIED HEC-TP_39 EEE~hEE~hEEE AUGUST 1972 -’ECHNICAL PAPER NO. 39 A METHOD FOR ANALYZING EFFECTS OF DAN FAILURES IN DESIGN STUDIES by WILLIAM...downstream structure. In the design studies for a dafm o be located downstreali from an existing dam, the effects of failure of the upstream structure...ANALYZING EFFECTS OF DAM FAILURES IN DESIGN STUDIES (1) by William A. Thomas (2 ) ABSTRACT In the planning and design of dams and embankments for large

  17. Design and implementation of PAVEMON: A GIS web-based pavement monitoring system based on large amounts of heterogeneous sensors data

    Science.gov (United States)

    Shahini Shamsabadi, Salar

    A web-based PAVEment MONitoring system, PAVEMON, is a GIS oriented platform for accommodating, representing, and leveraging data from a multi-modal mobile sensor system. Stated sensor system consists of acoustic, optical, electromagnetic, and GPS sensors and is capable of producing as much as 1 Terabyte of data per day. Multi-channel raw sensor data (microphone, accelerometer, tire pressure sensor, video) and processed results (road profile, crack density, international roughness index, micro texture depth, etc.) are outputs of this sensor system. By correlating the sensor measurements and positioning data collected in tight time synchronization, PAVEMON attaches a spatial component to all the datasets. These spatially indexed outputs are placed into an Oracle database which integrates seamlessly with PAVEMON's web-based system. The web-based system of PAVEMON consists of two major modules: 1) a GIS module for visualizing and spatial analysis of pavement condition information layers, and 2) a decision-support module for managing maintenance and repair (Mℝ) activities and predicting future budget needs. PAVEMON weaves together sensor data with third-party climate and traffic information from the National Oceanic and Atmospheric Administration (NOAA) and Long Term Pavement Performance (LTPP) databases for an organized data driven approach to conduct pavement management activities. PAVEMON deals with heterogeneous and redundant observations by fusing them for jointly-derived higher-confidence results. A prominent example of the fusion algorithms developed within PAVEMON is a data fusion algorithm used for estimating the overall pavement conditions in terms of ASTM's Pavement Condition Index (PCI). PAVEMON predicts PCI by undertaking a statistical fusion approach and selecting a subset of all the sensor measurements. Other fusion algorithms include noise-removal algorithms to remove false negatives in the sensor data in addition to fusion algorithms developed for

  18. A Comparison of Functional Models for Use in the Function-Failure Design Method

    Science.gov (United States)

    Stock, Michael E.; Stone, Robert B.; Tumer, Irem Y.

    2006-01-01

    When failure analysis and prevention, guided by historical design knowledge, are coupled with product design at its conception, shorter design cycles are possible. By decreasing the design time of a product in this manner, design costs are reduced and the product will better suit the customer s needs. Prior work indicates that similar failure modes occur with products (or components) with similar functionality. To capitalize on this finding, a knowledge base of historical failure information linked to functionality is assembled for use by designers. One possible use for this knowledge base is within the Elemental Function-Failure Design Method (EFDM). This design methodology and failure analysis tool begins at conceptual design and keeps the designer cognizant of failures that are likely to occur based on the product s functionality. The EFDM offers potential improvement over current failure analysis methods, such as FMEA, FMECA, and Fault Tree Analysis, because it can be implemented hand in hand with other conceptual design steps and carried throughout a product s design cycle. These other failure analysis methods can only truly be effective after a physical design has been completed. The EFDM however is only as good as the knowledge base that it draws from, and therefore it is of utmost importance to develop a knowledge base that will be suitable for use across a wide spectrum of products. One fundamental question that arises in using the EFDM is: At what level of detail should functional descriptions of components be encoded? This paper explores two approaches to populating a knowledge base with actual failure occurrence information from Bell 206 helicopters. Functional models expressed at various levels of detail are investigated to determine the necessary detail for an applicable knowledge base that can be used by designers in both new designs as well as redesigns. High level and more detailed functional descriptions are derived for each failed component based

  19. Preliminary Failure Modes and Effects Analysis of the US Massive Gas Injection Disruption Mitigation System Design

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, Lee C. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-10-01

    This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a candidate design for the ITER Disruption Mitigation System. This candidate is the Massive Gas Injection System that provides machine protection in a plasma disruption event. The FMEA was quantified with “generic” component failure rate data as well as some data calculated from operating facilities, and the failure events were ranked for their criticality to system operation.

  20. Recognizing Risk-of-Failure in Communication Design Projects

    Science.gov (United States)

    Yee, Joyce; Lievesley, Matthew; Taylor, Louise

    2009-01-01

    The pace of commercial graphic design practice presents very few opportunities to conduct user research after a project's launch. This makes the design team's ability to anticipate and address risks during the design development phase even more important, recognized in the astute observation from Tim Brown, CEO of leading international design…

  1. Guidelines for detection, analysis, and treatment of materials-related distress in concrete pavements, volume 3 : case studies using the guidelines.

    Science.gov (United States)

    2002-08-01

    The performance of concrete pavements can be adversely affected by the concrete's inability to resist the environment in : which it is placed. This lack of durability can occur even when the structural design of the pavement is adequate. The : distre...

  2. Proposed design method for large-stone asphalt and the implementation thereof in the rehabilitation of an airport pavement.

    CSIR Research Space (South Africa)

    Grobler, JE

    1992-07-01

    Full Text Available This paper addresses the development of a design procedure for large-stone asphalt, the implementation thereof in two sets of trial sections, the correlation of engineering properties obtained in the laboratory with field properties...

  3. Bridge Failure Due to Inadequate Design of Bed Protection

    Science.gov (United States)

    Gupta, Yogita; Kaur, Suneet; Dindorkar, Nitin

    2017-12-01

    The shallow foundation is generally provided on non-erodible strata or where scour depth is less. It is also preferable for low perennial flow or standing water condition. In the present case study shallow foundation is adopted for box type bridge. The total length of the bridge is 132.98 m, consisting of eight unit of RCC box. Each unit is composed of three cell box. The bottom slab of box unit is acted as raft foundation, founded 500 mm below ground level. River bed protection work is provided on both upstream and downstream side along the whole length of the bridge as it is founded above scour level. The bridge collapsed during the monsoon just after two years of service. The present paper explains the cause of failure. This study on failure of the bridge illustrates the importance of bridge inspection before and after monsoon period and importance of the timely maintenance. Standard specifications of Indian Road Congress for the river bed protection work are also included.

  4. Design and flight testing actuator failure accommodation controllers on WVU YF-22 research UAVs

    Science.gov (United States)

    Gu, Yu

    This dissertation describes the design, development, and flight testing of a Neural Network (NN) based Fault Tolerant Flight Control System (FTFCS) with the ability to accommodate for actuator failures. The goal of this research was to demonstrate the ability of a specific set of control laws to maintain aircraft handling qualities in the presence of failures in the actuator channels. In this study, two-failure scenarios have been investigated: aileron failure (locking of the right aileron at a trim position) and elevator failure (locking of the right elevator at a trim position). A fleet of WVU YF-22 research aircraft test-beds were manufactured and instrumented for developing and testing of flight control software. An on-board payload with a PC-104 format computer system, sensors, and custom made circuit boards were designed and developed for these aircraft test-beds. The fault tolerant flight control systems for this study were designed to recover the aircraft with damaged actuators. On-board real-time data acquisition and control software was developed to achieve the Actuator Failure Accommodation (AFA) flight demonstration. For the purposes of this research, control laws were required to be adaptive to changing aircraft dynamics during a failure scenario. On-line learning NNs---with their non-linearity and learning abilities---were used in the design of the on-board aircraft control scheme. The on-line training reduced the criticality of an extensive on-line Parameter IDentification (PID) during the failure and gives an on-board flight controller the capability to adjust to maintain the best possible flight performance during an unexpected failure. This document will outline and describe the design and building of the flight controller, aircraft test-beds, on-board payload systems, and software in detail. Flight test results will be presented and documented to demonstrate the performance of a NN based FTFCS under failure conditions.

  5. Optimization and standardization of pavement management processes.

    Science.gov (United States)

    2004-08-01

    This report addresses issues related to optimization and standardization of current pavement management processes in Kentucky. Historical pavement management records were analyzed, which indicates that standardization is necessary in future pavement ...

  6. The development of cost-effective pavement design approaches using minerology tests with new nano-technology modifications of materials

    CSIR Research Space (South Africa)

    Jordaan, G

    2017-07-01

    Full Text Available to determine the mineral composition of materials allows engineers not only to allow these “problem” materials to be identified, but also to address the “perceived risk” of these materials during the design process. New proven Nano-technologies developed over...

  7. HYBRID HUMAN-ARTIFICIAL INTELLIGENCE APPROACH FOR PAVEMENT DISTRESS ASSESSMENT (PICUCHA)

    OpenAIRE

    Reus Salini; Bugao Xu; Regis Carvalho

    2017-01-01

    The pavement surface condition assessment is a critical component for a proper pavement management system as well as for pavement rehabilitation design. A number of devices were developed to automatically record surface distresses in a continuous survey mode, but the software required for automatic distress identification remains a big challenge. In this study, a new method named PICture Unsupervised Classification with Human Analysis (PICUCHA) is proposed to circumvent many of the limitation...

  8. Inferring pavement layer properties from a moving measurement platform

    DEFF Research Database (Denmark)

    Andersen, Sebastian; Levenberg, Eyal; Andersen, M.B.

    2017-01-01

    This work offered a new method for accessing the mechanical properties of pavement layers based on data obtained by a moving measurement platform. The method has the following features: (i) calculations are based on tracking distances to a point on the pavement surface, (ii) measurements...... are not required outside the zone of load influence, and (iii) possibility to access absolute pavement deflections. First, the envisioned platform-design and required readings were presented; next, the interpretation method was outlined and then applied to synthetic (computer-generated) data. Perfect convergence...... was achieved when the correct pavement model and accurate input data were employed. Also, when artificial errors were introduced for assessing sensitivities, only small deviations were generated. Based on these promising outcomes the method will be further studied and developed to support the construction...

  9. Applications of waste material in the pervious concrete pavement: A review

    Science.gov (United States)

    Shakrani, Shahrul Azwan; Ayob, Afizah; Rahim, Mohd Asri Ab

    2017-09-01

    Pervious concrete pavement is one of the innovative structures designed in order to manage the quantity and quality of urban stormwater for a sustainable development. In general, pervious concrete pavement enables water to permeate through its structure and have a capability to cater dynamic loads at the same time. However, the conventional pervious concrete pavement lacks a superior strength while performing as pavement structure. Thus, an extensive research has been carried out in order to explore the possible materials to be incorporated into the pervious concrete pavement for better physical, structural and mechanical properties. The objectives of this paper are to review the waste materials used in the pervious concrete pavement along with their mechanical, durability and permeability performance.

  10. Research on the characteristics of temperature field of asphalt pavement in seasonal frozen region

    International Nuclear Information System (INIS)

    Qiao, Jiangang; Liu, Weizheng

    2014-01-01

    The characteristics of climate in seasonal frozen area are low temperature and a large range of temperature variation between day and night in winter. These characteristics often lead to problems of asphalt pavement, especially transverse cracks. To reduce the problems of asphalt pavement, it is necessary to examine the distribution of the temperature range of asphalt pavement. A three-dimensional finite element model was used, taking the SMA asphalt pavement as an example with solid70 and plane55 unit features of ANSYS software. It can obtain the relationship between temperature gradient and time and the relationship between temperature gradient and depth. In addition, a function relation model of stress and time was also established. It can provide a theoretical basis for the prevention and treatment of problems of asphalt pavement in seasonal frozen area. Moreover, it has an important significance for improving asphalt pavement design

  11. Flexibl Pavement Analysis Considering Temperature Profile and Anisotropy Behavior in Hot Mix Asphalt Layer

    Directory of Open Access Journals (Sweden)

    Choi Joonho

    2011-12-01

    Full Text Available A three Dimensional finite element model (FEM incorporating the anisotropic properties and temperature profile of hot mix asphalt (HMA pavement was developed to predict the structural responses of HMA pavement subject to heavy loads typically encountered in the field. In this study, ABAQUS was adopted to model the stress and strain relationships within the pavement structure. The results of the model were verified using data collected from the Korean Highway Corporation Test Road (KHCTR. The results demonstrated that both the base course and surface course layers follow the anisotropic behavior and the incorporation of the temperature profile throughout the pavement has a substantial effect on the pavement response predictions that impact pavement design. The results also showed that the anisotropy level of HMA and base material can be reduced to as low as 80% and 15% as a result of repeated loading, respectively.

  12. Prediction of average annual surface temperature for both flexible and rigid pavements

    Directory of Open Access Journals (Sweden)

    Karthikeyan LOGANATHAN

    2017-12-01

    Full Text Available The surface temperature of pavements is a critical attribute during pavement design. Surface temperature must be measured at locations of interest based on time-consuming field tests. The key idea of this study is to develop a temperature profile model to predict the surface temperature of flexible and rigid pavements based on weather parameters. Determination of surface temperature with traditional techniques and sensors are replaced by a newly developed method. The method includes the development of a regression model to predict the average annual surface temperature based on weather parameters such as ambient air temperature, relative humidity, wind speed, and precipitation. Detailed information about temperature and other parameters are extracted from the Federal Highway Administration's (FHWA Long Term Pavement Performance (LTPP online database. The study was conducted on 61 pavement sections in the state of Alabama for a 10-year period. The developed model would predict the average annual surface temperature based on the known weather parameters. The predicted surface temperature model for asphalt pavements was very reliable and can be utilized while designing a pavement. The study was also conducted on seven rigid pavement sections in Alabama to predict their surface temperature, in which a successful model was developed. The outcome of this study would help the transportation agencies by saving time and effort invested in expensive field tests to measure the surface temperature of pavements.

  13. Perpetual pavement – absorbing stress and functional maintenance

    Directory of Open Access Journals (Sweden)

    Rong Gao

    2017-03-01

    Full Text Available Perpetual Pavement combines the well documented smoothness and safety advantages of asphalt with an advanced, multi-layer paving design process, that with routine maintenance, extends the useful life of a roadway. Perpetual provides long lasting road and smoothness for the construction purposes. This study has the design key points of perpetual pavement based on the idea of life cycle, which has a new direction for the new highway construction, reconstruction and expansion. First, the structure of long life pavement design is studied to analyze the effect of stress absorbing layer. Second, researches on stress absorbing layer from the aspects of raw materials, mix proportion are implemented. Third, the design index of stress absorbing layer is determined by the shear strength test. The results show that the design idea of composite perpetual pavement can be realized by reasonable design of the stress absorbing layer and carrying out the surface functional maintenance can ensure the pavement to avoid structural damage in the operation stage.

  14. Automatic Monitoring System Design and Failure Probability Analysis for River Dikes on Steep Channel

    Science.gov (United States)

    Chang, Yin-Lung; Lin, Yi-Jun; Tung, Yeou-Koung

    2017-04-01

    The purposes of this study includes: (1) design an automatic monitoring system for river dike; and (2) develop a framework which enables the determination of dike failure probabilities for various failure modes during a rainstorm. The historical dike failure data collected in this study indicate that most dikes in Taiwan collapsed under the 20-years return period discharge, which means the probability of dike failure is much higher than that of overtopping. We installed the dike monitoring system on the Chiu-She Dike which located on the middle stream of Dajia River, Taiwan. The system includes: (1) vertical distributed pore water pressure sensors in front of and behind the dike; (2) Time Domain Reflectometry (TDR) to measure the displacement of dike; (3) wireless floating device to measure the scouring depth at the toe of dike; and (4) water level gauge. The monitoring system recorded the variation of pore pressure inside the Chiu-She Dike and the scouring depth during Typhoon Megi. The recorded data showed that the highest groundwater level insides the dike occurred 15 hours after the peak discharge. We developed a framework which accounts for the uncertainties from return period discharge, Manning's n, scouring depth, soil cohesion, and friction angle and enables the determination of dike failure probabilities for various failure modes such as overtopping, surface erosion, mass failure, toe sliding and overturning. The framework was applied to Chiu-She, Feng-Chou, and Ke-Chuang Dikes on Dajia River. The results indicate that the toe sliding or overturning has the highest probability than other failure modes. Furthermore, the overall failure probability (integrate different failure modes) reaches 50% under 10-years return period flood which agrees with the historical failure data for the study reaches.

  15. Optimal tread design for agricultural lug tires determined through failure analysis

    Directory of Open Access Journals (Sweden)

    Hyun Seok Song

    2018-04-01

    Full Text Available Agricultural lug tires, commonly used in tractors, must provide safe and stable support for the body of the vehicle and bear any additional load while effectively traversing rough, poor-quality ground surfaces. Many agricultural lug tires fail unexpectedly. In this study, we optimised and validated a tread design for agricultural lug tires intended to increase their durability using failure analysis. Specifically, we identified tire failure modes using indoor driving tests and failure mode effects analysis. Next, we developed a threedimensional tire model using the Ogden material model and finite element method. Using sensitivity analysis and response surface methodology, we optimised the tread design. Finally, we evaluated the durability of the new design using a tire prototype and drum test equipment. Results indicated that the optimised tread design decreased the tire tread stress by 16% and increased its time until cracking by 38% compared to conventional agricultural lug tires.

  16. Processes in construction of failure management expert systems from device design information

    Science.gov (United States)

    Malin, Jane T.; Lance, Nick

    1987-01-01

    This paper analyzes the tasks and problem solving methods used by an engineer in constructing a failure management expert system from design information about the device to te diagnosed. An expert test engineer developed a trouble-shooting expert system based on device design information and experience with similar devices, rather than on specific expert knowledge gained from operating the device or troubleshooting its failures. The construction of the expert system was intensively observed and analyzed. This paper characterizes the knowledge, tasks, methods, and design decisions involved in constructing this type of expert system, and makes recommendations concerning tools for aiding and automating construction of such systems.

  17. How to Flip the Classroom--"Productive Failure or Traditional Flipped Classroom" Pedagogical Design?

    Science.gov (United States)

    Song, Yanjie; Kapur, Manu

    2017-01-01

    The paper reports a quasi-experimental study comparing the "traditional flipped classroom" pedagogical design with the "productive failure" (Kapur, 2016) pedagogical design in the flipped classroom for a 2-week curricular unit on polynomials in a Hong Kong Secondary school. Different from the flipped classroom where students…

  18. Evaluation of pavement skid resistance using high speed texture measurement

    Directory of Open Access Journals (Sweden)

    Jay N. Meegoda

    2015-12-01

    Full Text Available Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth (MPD or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number (SN40R collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.

  19. Application of Westergaard Method for assessment of interaction of Hercules C-130 plane on airport pavement

    Directory of Open Access Journals (Sweden)

    Karolina Gulańczyk

    2015-09-01

    Full Text Available The following paper describes original solution and methodology of calculating elastic pavements loaded by aircraft’s leg in arrangement of wheels in tandem.Using Border Load Capacity State Method, the authors have developed nomographs for determining the equivalent load, which could be further applied in Westergaard’s pavement calculation approach. Derived the state-of-the-art equation and nomographs have not been considered yet. For this reason, they are valuable sources of information for aircraft pavement designers.Considering the pavement loaded by military cargo aircraft (HERCULESERCULES C-130, the authors performed calculations of pavement stresses and its deflection in the function of pavement thickness and soil parameters. These computations resulted in obtaining diagrams presenting pavement stress variation in the function of parameters described herein.Diagrams obtained using Border Load Capacity State Method will certainly accelerate the procedure of calculating the construction of stiff pavements loaded by the aircrafts with tandem arrangement of wheels.[b]Keyword[/b][b]s[/b]: concrete airport pavements, capacity limit state method, system wheels in tandem

  20. Lunar Module Wiring Design Considerations and Failure Modes

    Science.gov (United States)

    Interbartolo, Michael

    2009-01-01

    This slide presentation reviews the considerations for the design of wiring for the Lunar Module. Included are a review of the choice of conductors and insulations, the wire splicing (i.e., crimping, and soldering), the wire connectors, and the fabrication of the wire harnesses. The problems in fabrication include the wires being the wrong length, the damage due to the sharp edges, the requried use of temproary protective covers and inadequate training. The problems in the wire harness installation include damge from sharp eges, work on adjacent harnesses, connector damage, and breaking wires. Engineering suggestions from the Apollo-era in reference to the conductors that are reviewed include: the use of plated conductors, and the use of alloys for stronger wiring. In refernce to insulation, the suggestions from Apollo era include the use of polymer tape-wrap wire insulation due to the light weight, however, other types of modern insulation might be more cost-effective. In reference to wire splices and terminal boards the suggestions from the Apollo Era include the use of crimp splices as superior to solder splices, joining multiple wire to a common point using modular plug-ins might be more reliable, but are heavier than crimp splicing. For connectors, the lessons from the Apollo era indicate that a rear environmental seal that does not require additional potting is preferred, and pins should be crimped or welded to the incoming wires and be removable from the rear of the connector.

  1. Active zone impact on deformation state of non-rigid pavement

    Directory of Open Access Journals (Sweden)

    Mandula Ján

    2014-06-01

    Full Text Available The paper deals with the design of non-rigid pavement, with emphasis on the effect of active zone on its deformation state. The concepts of determination of active zone are described. The results of numerical modelling of pavement laying on elastic subgrade are presented in the paper

  2. Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System

    Science.gov (United States)

    The U.S. Environmental Protection Agency constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable pavement in the parking lanes which were designed to receive run-on from the impervious hot-mix asphalt driving lanes. Twelve lined permeable pavement sec...

  3. Bioinspired design and interfacial failure of biomedical systems

    Science.gov (United States)

    Rahbar, Nima

    The deformation mechanism of nacre as a model biological material is studied in this project. A numerical model is presented which consists of tensile pillars, shear pillars, asperities and aragonite platelets. It has been shown that the tensile pillars are the main elements that control the global stiffness of the nacre structure. Meanwhile, ultimate strength of the nacre structure is controlled by asperities and their behavior and the ratio of L/2D which is itself a function of the geometry of the platelets. Protein/shear pillars provide the glue which holds the assembly of entire system together, particularly in the direction normal to the platelets main axis. This dissertation also presents the results of a combined theoretical/computational and experimental effort to develop crack resistant dental multilayers that are inspired by the functionally graded dento-enamel junction (DEJ) structure that occurs between dentin and enamel in natural teeth. The complex structures of natural teeth and ceramic crowns are idealized using at layered configurations. The potential effects of occlusal contact are then modeled using finite element simulations of Hertzian contact. The resulting stress distributions are compared for a range of possible bioinspired, functionally graded architecture. The computed stress distributions show that the highest stress concentrations in the top ceramic layer of crown structures are reduced significantly by the use of bioinspired functionally graded architectures. The reduced stresses are shown to be associated with significant improvements (30%) in the pop-in loads over a wide range of clinically-relevant loading rates. The implications of the results are discussed for the design of bioinspired dental ceramic crown structures. The results of a combined experimental and computational study of mixed mode fracture in glass/cement and zirconia/cement interfaces that are relevant to dental restorations is also presented. The interfacial fracture

  4. Incorporating Traffic Speed Deflection Data in Pavement Management Decision Making for Flexible Pavements

    OpenAIRE

    Thyagarajan, Senthilmurugan; Sivaneswaran, Nadarajah; Petros, Katherine

    2015-01-01

    Systematic pavement condition evaluation and development of an optimized set of pavement treatment strategies are two key tasks in the pavement management process that assists in making informed decisions on future construction actions. Current State Highway Agency's pavement management systems are primarily based on surface condition data, and surface cracking is mainly used as an indicator of the pavement structural condition. However, with effective pavement preservation activities that in...

  5. Motivational Interviewing Tailored Interventions for Heart Failure (MITI-HF): study design and methods.

    Science.gov (United States)

    Masterson Creber, Ruth; Patey, Megan; Dickson, Victoria Vaughan; DeCesaris, Marissa; Riegel, Barbara

    2015-03-01

    Lack of engagement in self-care is common among patients needing to follow a complex treatment regimen, especially patients with heart failure who are affected by comorbidity, disability and side effects of poly-pharmacy. The purpose of Motivational Interviewing Tailored Interventions for Heart Failure (MITI-HF) is to test the feasibility and comparative efficacy of an MI intervention on self-care, acute heart failure physical symptoms and quality of life. We are conducting a brief, nurse-led motivational interviewing randomized controlled trial to address behavioral and motivational issues related to heart failure self-care. Participants in the intervention group receive home and phone-based motivational interviewing sessions over 90-days and those in the control group receive care as usual. Participants in both groups receive patient education materials. The primary study outcome is change in self-care maintenance from baseline to 90-days. This article presents the study design, methods, plans for statistical analysis and descriptive characteristics of the study sample for MITI-HF. Study findings will contribute to the literature on the efficacy of motivational interviewing to promote heart failure self-care. We anticipate that using an MI approach can help patients with heart failure focus on their internal motivation to change in a non-confrontational, patient-centered and collaborative way. It also affirms their ability to practice competent self-care relevant to their personal health goals. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Design Thinking for mHealth Application Co-Design to Support Heart Failure Self-Management.

    Science.gov (United States)

    Woods, Leanna; Cummings, Elizabeth; Duff, Jed; Walker, Kim

    2017-01-01

    Heart failure is a prevalent, progressive chronic disease costing in excess of $1billion per year in Australia alone. Disease self-management has positive implications for the patient and decreases healthcare usage. However, adherence to recommended guidelines is challenging and existing literature reports sub-optimal adherence. mHealth applications in chronic disease education have the potential to facilitate patient enablement for disease self-management. To the best of our knowledge no heart failure self-management application is available for safe use by our patients. In this paper, we present the process established to co-design a mHealth application in support of heart-failure self-management. For this development, an interdisciplinary team systematically proceeds through the phases of Stanford University's Design Thinking process; empathise, define, ideate, prototype and test with a user-centred philosophy. Using this clinician-led heart failure app research as a case study, we describe a sequence of procedures to engage with local patients, carers, software developers, eHealth experts and clinical colleagues to foster rigorously developed and locally relevant patient-facing mHealth solutions. Importantly, patients are engaged in each stage with ethnographic interviews, a series of workshops and multiple re-design iterations.

  7. When Failure Is Not An Option: Designing Competency-Based Pathways for Next Generation Learning

    Science.gov (United States)

    Sturgis, Chris; Patrick, Susan

    2010-01-01

    This exploration into competency-based innovation at the school, district, and state levels suggests that competency-based pathways are a re-engineering of this nation's education system around learning--a re-engineering designed for success in which failure is no longer an option. Competency-based approaches build upon standards reforms, offering…

  8. Fuzzy Based Design for Third-Party Pipeline Failures in the Niger ...

    African Journals Online (AJOL)

    A Fuzzy based design for assessing failures of pipelines occasioned by third party in the Niger Delta Region of Nigeria has been proposed in this study. Twelve factors earlier identified by Ariavie et al (2010), were further grouped into four, viz : violence, desperation, misconduct and agricultural categories to allow for a less ...

  9. A Further Study of Productive Failure in Mathematical Problem Solving: Unpacking the Design Components

    Science.gov (United States)

    Kapur, Manu

    2011-01-01

    This paper replicates and extends my earlier work on productive failure in mathematical problem solving (Kapur, doi:10.1007/s11251-009-9093-x, 2009). One hundred and nine, seventh-grade mathematics students taught by the same teacher from a Singapore school experienced one of three learning designs: (a) traditional lecture and practice (LP), (b)…

  10. Calibration on MEPDG Low Temperature Cracking Model and Recommendation on Asphalt Pavement Structures in Seasonal Frozen Region of China

    Directory of Open Access Journals (Sweden)

    Hongyan Ma

    2015-01-01

    Full Text Available In order to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG to design and maintain asphalt pavements in China, it is necessary to calibrate transfer functions of distresses in MEPDG with local conditions, including traffics, environment, and materials as well as measured pavement distresses data in field. Comprehensive single factor sensitivity analyses of factors that influence thermal cracking of asphalt pavements were conducted utilizing the MEPDG low temperature cracking (LTC model. Additionally, multiple factor sensitivity analyses were carried out as well, based on which pavement structures with sound thermal cracking resistance were recommended for seasonal frozen regions in China. Finally, the field data of thermal cracks on typical asphalt pavements in China was utilized to calibrate the LTC model in MEPDG. An improvement was proposed on MEPDG LTC model, after which was applied, the predicted thermal cracking from MEPDG LTC model agrees well with measured thermal cracking in China.

  11. Design Failure Affecting Maintenance Management on Public Higher Education Institution in Malaysia

    Directory of Open Access Journals (Sweden)

    Agus Salim Nuzaihan Aras

    2016-01-01

    Full Text Available The issue of government building defect is keeping on reporting in the media and arising since 2007. These issues of building defects, maintenance and management have existing and it is deliberated up to the parliament level. The government keep continue increased the maintenance allowance in National Budgetary in every year. However, the building disasters and failures keep going develop their number of cases in Malaysia. Most of the issues are related with a weak maintenance management and faulty in design. This reflects to a poorly building condition, create discomfort and danger environment to the building users. Besides, it will result to a low quality building condition and reflect to a weak building maintenance management. Building defects arise through inappropriate or poor design, specification, construction and it will give an impact to maintenance management itself [1]. Errors in the design of the building are being debated and becoming a reason of major factor in building defect reproduction [2]. Thus, this issue will discover the major cause in building design failure that develop the building defects and verify the impact of design defects towards building maintenance management. The study involved with the public higher education institution in Malaysia focusing on main campuses and the distribution of questionnaire to the facility and maintenance management department. This research is aimed to produce a better understanding on the impact of building design failure towards the institution facilities’ condition.

  12. Configurations Of Tire Pressure On The Pavement For Commercial Vehicles: Calculation Of The ‘N’ Number And The Consequences On Pavement Performance

    Directory of Open Access Journals (Sweden)

    Paulo Boulos Filho

    2016-07-01

    Full Text Available Road traffic has a high variety of types of vehicles and cargo transported. One of the main difficulties in pavement design is forecasting the changes in traffic over time and evaluating the comparative deterioration power of the various loads with axle and tire settings and different levels of repetition. The road environment in Brazil, as we know, is the main means of the country's cargo transportation. Throughout the 1990s and 2000s the road modal accounted for over 60% of the total cargo transported in the country leaving the unbalanced Brazilian transport matrix with almost exclusive investments in such means of transportation. According to CNT 2012, which conducted a survey in approximately 45% of the paved network, evaluating the pavement functional conditions, traffic signs and geometry, 46% of the country’s road network has some type of deficiency in the pavement. The goal of this work is to contribute to a better understanding of the complex influence of traffic in the design and service life of the pavement. The load pressure of commercial vehicle tires over the pavement has increased in recent decades. A more apparent effect of this increase in tire pressure would be the change in the pavement- tire contact area which in turn may result in an increase in the contact load between tire and pavement and other harmful effects on the structure. This study aims to determine the effect on the calculation of the N number, or the number of solicitations of the standard axle on the road pavement, measuring the overload as a percentage of the legal load indicated by a scale. In short, we calculate how an increase in the overload percentage in comparison with the allowable load will influence the decrease of the calculated durability of the pavement designed for the highway.

  13. Influence of the condition of the airfield pavement structures on the operation safety of aircraft

    Directory of Open Access Journals (Sweden)

    Wesołowski Mariusz

    2017-06-01

    Full Text Available The structure of the airfield pavement is a set of layers, whose task is to take over and transfer loads from moving aircraft to a ground subsoil in a safety manner. Airfield pavements are designed for a specific period of operation, assuming the forecasted intensity and the structure of the air traffic. The safety of air operations executed by the aircraft on airfield pavements depends primarily on the condition of their structure’s load capacity. In order to assess the load capacity of airfield pavements, the method ACN-PCN, which was introduced by the International Civil Aviation Organization ICAO and according to which the load capacity of the airfield pavement is expressed with the PCN index, is applied.

  14. Pervious Pavement System Evaluation- Abstract

    Science.gov (United States)

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  15. Premature asphalt concrete pavement cracking.

    Science.gov (United States)

    2015-06-01

    Recently, the Oregon Department of Transportation (ODOT) has identified hot mix asphalt concrete : (HMAC) pavements that have displayed top-down cracking within three years of construction. The objective of : the study was to evaluate the top-down cr...

  16. Pavement management using hyperspectral imagery

    Science.gov (United States)

    Ayalew, Balehager; Gomez, Richard B.; Roper, William E.; Carrasco, Oscar

    2003-08-01

    Public Works facilities require up-to-date information on the health status of the road network they maintain. However, roadway maintenance and rehabilitation involves the greatest portion of a municipality's annual operating budget. Government officials use various technologies such as a pavement management system to assist in making better decisions about their roadways systems, pavement condition, history, and projects. Traditionally, manual surveying has served as the method of obtaining this information. To better assist in decision-making, a regionally specific spectral library for urban areas is being developed and used in conjunction with hyperspecrtal imaging, to map urban materials and pavement conditions. A Geographical Information and Positioning System (GIS/GPS) will also be implemented to overlay relative locations. This paper will examine the benefits of using hyperspectral imaging over traditional methods of roadway maintenance and rehabilitation for pavement management applications. In doing so, we will identify spatial and spectral requirements for successful large-scale road feature extraction.

  17. FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING

    Directory of Open Access Journals (Sweden)

    V. A. Osinovskaya

    2015-01-01

    Full Text Available The problem of low durability of flexible pavement is one of the most important problems of road economy. For example, the actual service life of asphalt pavement in Russia about 3 … 5 years. The bad condition of highways is an obstacle for the development of the national economy and leads to a significant annual economic losses.At present, this problem has no exact solution. Even at the seeming good road conditions of Europe and America the problem of low durability is no less important in these countries. And this problem becomes more and more actual every year.Our scientific researches allowed to make a hypothesis that the projected of pavements are not have the necessary durability yet not of a stage of designing because in strength calculations did not take into account the vibration of road constructions.Very actual the vibration loading becomes today as is now significantly changed the nature of loading of pavements. As a result the deflections of a pavements are reduced, but the increased vibration of pavements accelerated processes of destruction and significantly reduced durability.The theory of vibration destruction developed by the author allows to adjust the vibration, to form the vibration resistance pavements, and also to forecast a residual life of pavements that will more effectively develop repair actions.

  18. Environmentally Friendly Pavements: final report

    OpenAIRE

    Aksnes, Jostein

    2009-01-01

    This final report presents the main results, advice and recommendations from the research and development program Environmentally Friendly Pavements run by the Norwegian Public Roads Administration (NPRA) in the period 2004-2009. The main focus of the project has been to optimise the environmental properties of road surfaces with respect to low road tyre noise and road dust emissions. The project has shown that: The tested environmentally friendly pavements give an initial noise r...

  19. Intelligent system for pavement management

    Science.gov (United States)

    Ferreira Brega, Jose R.; Alba Soria, Manoel H.; Marar, Joao F.; Sementille, Antonio C.

    1998-03-01

    This paper describes a method for the evaluation of pavement condition through artificial neural networks using the MLP backpropagation technique. Two of the most used procedures for detecting the pavement conditions were applied: the 'overall severity index' and the 'irregularity index.' Tests with the model demonstrated that the simulation with the neural network gives better results than the procedures recommended by the highway officials. This network may also be applied for the construction of a graphic computer environment.

  20. Effect of interlayer bonding quality of asphalt layers on pavement performance

    Science.gov (United States)

    Jaskula, Piotr; Rys, Dawid

    2017-09-01

    The quality of interlayer bonding at the interfaces between the asphalt layers in flexible pavements affects the overall pavement performance. Lack or partial lack of interlayer bonding between asphalt layers can cause pavement’s premature failures such as rutting, slippage of the wearing course, cracking or simply a reduction in the calculated fatigue life of the pavement structure. This paper shows the case studies of investigation of actual or potential premature failure of newly reconstructed and constructed pavements where low quality of interlayer bonding has a dominant meaning. In situ and laboratory tests were performed and followed by analytical calculation of pavement structure where thicknesses of layers and maximum shear strengths obtained from the tests were used. During the investigation it was found out that a low quality of tack coat as well as the same aggregate gradation in the bonded asphalt mixtures were the main reasons behind the weak quality of interlayer bonding. Partial interlayer bonding has a strong influence on reduction of calculated fatigue life of pavement. The summary of the paper includes recommendations on how to avoid the low quality of interlayer bonding of asphalt layers.

  1. Observation Likelihood Model Design and Failure Recovery Scheme Toward Reliable Localization of Mobile Robots

    Directory of Open Access Journals (Sweden)

    Chang-bae Moon

    2010-12-01

    Full Text Available Although there have been many researches on mobile robot localization, it is still difficult to obtain reliable localization performance in a human co-existing real environment. Reliability of localization is highly dependent upon developer's experiences because uncertainty is caused by a variety of reasons. We have developed a range sensor based integrated localization scheme for various indoor service robots. Through the experience, we found out that there are several significant experimental issues. In this paper, we provide useful solutions for following questions which are frequently faced with in practical applications: 1 How to design an observation likelihood model? 2 How to detect the localization failure? 3 How to recover from the localization failure? We present design guidelines of observation likelihood model. Localization failure detection and recovery schemes are presented by focusing on abrupt wheel slippage. Experiments were carried out in a typical office building environment. The proposed scheme to identify the localizer status is useful in practical environments. Moreover, the semi-global localization is a computationally efficient recovery scheme from localization failure. The results of experiments and analysis clearly present the usefulness of proposed solutions.

  2. Observation Likelihood Model Design and Failure Recovery Scheme toward Reliable Localization of Mobile Robots

    Directory of Open Access Journals (Sweden)

    Chang-bae Moon

    2011-01-01

    Full Text Available Although there have been many researches on mobile robot localization, it is still difficult to obtain reliable localization performance in a human co-existing real environment. Reliability of localization is highly dependent upon developer's experiences because uncertainty is caused by a variety of reasons. We have developed a range sensor based integrated localization scheme for various indoor service robots. Through the experience, we found out that there are several significant experimental issues. In this paper, we provide useful solutions for following questions which are frequently faced with in practical applications: 1 How to design an observation likelihood model? 2 How to detect the localization failure? 3 How to recover from the localization failure? We present design guidelines of observation likelihood model. Localization failure detection and recovery schemes are presented by focusing on abrupt wheel slippage. Experiments were carried out in a typical office building environment. The proposed scheme to identify the localizer status is useful in practical environments. Moreover, the semi-global localization is a computationally efficient recovery scheme from localization failure. The results of experiments and analysis clearly present the usefulness of proposed solutions.

  3. A Fundamental Investigation into the Deformation and Failure Behavior of Heterogeneous Materials with the Aims of Developing Design Guidelines

    National Research Council Canada - National Science Library

    Ravi-Chandar, Krishnaswamy

    2000-01-01

    ... at the microscale to the macroscale design of composite structures. This is important since the deformation and failure behavior under multiaxial is not well understood, nor are there suitable design guidelines or material allowables clearly defined...

  4. Accelerated pavement testing efforts using the heavy vehicle simulator

    CSIR Research Space (South Africa)

    Du Plessis, Louw

    2017-10-01

    Full Text Available of the University of Costa Rica and the Mexico Institute of Trans- portation amongst others. Brief descriptions of HVS research and summaries of key results from these programs are provided. Planned research is covered where available. � 2017 Chinese Society...-empirical design models using laboratory materials testing characterization and real, long-term pavement performance monitoring and analysis data.https://doi.org/10.1016/j.ijprt.2017.09.016 1996-6814/� 2017 Chinese Society of Pavement Engineering. Production...

  5. A pavement Moisture Accelerated Distress (MAD) identification system, volume 2

    Science.gov (United States)

    Carpenter, S. H.; Darter, M. I.; Dempsey, B. J.

    1981-09-01

    A users manual is designed which provides the engineer with a rational method of examining a pavement and determining rehabilitation needs that are related to the causes of the existing distress, particularly moisture related distress. The key elements in this procedure are the MAD Index developed in Volume 1, the Pavement Condition Index (PCI) and the Moisture Distress Index (MDI). Step by step procedures are presented for calculating each parameter. Complete distress identification manuals are included for asphalt surfaced highways and jointed reinforced concrete highways with pictures and descriptions of all major distress types. Descriptions of the role moisture plays in the development of each distress type are included.

  6. Patients with heart failure as co-designers of an educational website: implications for medical education.

    Science.gov (United States)

    Kristiansen, Anne Mette; Svanholm, Jette R; Schjødt, Inge; Mølgaard Jensen, Karsten; Silén, Charlotte; Karlgren, Klas

    2017-02-25

    To identify the learning needs of patients with heart failure between outpatients follow-up visits from their perspective and to ascertain what they emphasize as being important in the design of an educational website for them. We conducted a two-step qualitative study at Aarhus University Hospital, Denmark. Twenty patients with heart failure participated either in focus group interviews, diary writing, or video-recorded design sessions. Data on learning needs were collected in step 1 and analyses, therefore, helped develop the preliminary prototypes of a website. In step 2, patients worked on the prototypes in video-recorded design sessions, employing a think-aloud method. The interviews were transcribed and a content analysis was performed on the text and video data. Patients' learning needs were multifaceted, driven by anxiety, arising from, and often influenced by, such daily situations and contexts as the medical condition, medication, challenges in daily life, and where to get support and how to manage their self-care. They emphasized different ways of adapting the design to the patient group to enable interaction with peers and professionals and specific interface issues. This study provided insights into the different learning needs of patients with heart failure, how managing daily situations is the starting point for these needs and how emotions play a part in patients' learning. Moreover, it showed how patient co-designers proved to be useful for understanding how to design a website that supports patients' learning: insights, which may become important in designing online learning tools for patients.

  7. Early Subsidence Predicts Failure of a Cemented Femoral Stem With Minor Design Changes.

    Science.gov (United States)

    Johanson, Per-Erik; Antonsson, Martin; Shareghi, Bita; Kärrholm, Johan

    2016-10-01

    Radiostereometry (RSA) measurements of early micromotion can predict later failure in hip and knee prostheses. In hip implants, RSA has been particularly helpful in the evaluation of composite-beam stem designs. The Spectron EF Primary stem (Smith & Nephew, London, UK) has shown inferior performance compared with its predecessors in both clinical studies and registry reports. Early RSA studies have shown somewhat greater subsidence for the Spectron EF Primary stem compared with the earlier Spectron EF, but still within boundaries considered to be safe. Our primary research question was whether stem subsidence and rotation for this stem design measured with RSA at 2 years can predict later stem failure. A secondary question was whether high femoral stem offset and small stem sizes, both features specific to the Spectron EF Primary stem compared with its predecessors, are associated with stem failure rate. Two hundred forty-seven hips (209 patients with median age 63 years [range, 29-80 years], 65% female, and 77% primary osteoarthritis) with a valid RSA examination at 2 years were selected from four different RSA studies (totaling 279 hips in 236 patients) in our department. The studies were primarily aimed at evaluating cup fixation, bone cement, and polyethylene types. All study patients received a cemented Spectron EF Primary stem. The selected hips had complete followup until stem failure, death, or the end of the followup period. Stem failure was defined as revision of a loose femoral stem or radiological failure with significant osteolysis in Gruen zones 2 to 6. Cox regression analyses were performed to evaluate if stem subsidence and rotation after 2 years, adjusted for age, sex, stem size, standard/high stem offset, and conventional/highly crosslinked polyethylene, could predict later clinical aseptic failure of the stem. We identified 32 stem failures (27 revisions, five radiological failures) at 14 years median followup (range, 3-18 years). Ten-year stem

  8. Sildenafil in heart failure with reactive pulmonary hypertension (Sildenafil HF) clinical trial (rationale and design)

    OpenAIRE

    Guglin, Maya; Rajagopalan, Navin; Anaya, Paul; Charnigo, Richard

    2016-01-01

    In this article, we present the rationale and design of the Sildenafil HF trial (ClinicalTrials.gov identifier: NCT02304705). We will randomize patients with heart failure and reactive pulmonary hypertension (pulmonary capillary wedge pressure > 15 mmHg, pulmonary vascular resistance > 3 Wood units) into two groups: the treatment group receiving sildenafil 20 mg 3 times a day and a matching placebo group. The duration of intervention will be 3 months. The primary outcome is 6-minute walk dist...

  9. Calibration of PMIS pavement performance prediction models.

    Science.gov (United States)

    2012-02-01

    Improve the accuracy of TxDOTs existing pavement performance prediction models through calibrating these models using actual field data obtained from the Pavement Management Information System (PMIS). : Ensure logical performance superiority patte...

  10. Pervious Pavement System Evaluation-Poster

    Science.gov (United States)

    Pervious pavement is a low impact development stormwater control. The Environmental Protection Agency's Urban Watershed Management Branch is evaluating interlocking concrete pavingstone pervious pavement systems. The pavingstones themselves are impermeable, but the spaces between...

  11. Equivalent damage of loads on pavements

    CSIR Research Space (South Africa)

    Prozzi, JA

    2009-05-26

    Full Text Available This report describes a new methodology for the determination of Equivalent Damage Factors (EDFs) of vehicles with multiple axle and wheel configurations on pavements. The basic premise of this new procedure is that "equivalent pavement response...

  12. Dynamic contracting mechanism for pavement maintenance management

    NARCIS (Netherlands)

    Demirel, H.C.; De Ridder, H.A.J.

    2013-01-01

    Technological advances, financial possibilities and changes of demands have increasingly affected the pavement maintenance environment for outsourcing in recent years. This induces complexity in the contracting methods of pavement maintenance activities. Despite the fact that current contracting

  13. Minimization of reflection cracks in flexible pavements.

    Science.gov (United States)

    1977-01-01

    This report describes the performance of fabrics used under overlays in an effort to minimize longitudinal and alligator cracking in flexible pavements. It is concluded, although the sample size is small, that the treatments will extend the pavement ...

  14. Evaluation of pavement surface friction treatments.

    Science.gov (United States)

    2011-12-01

    The implementation of a pavement preservation program involves a learning curve with not only a determination to succeed, but : also the courage to fail. Also, successful implementation of pavement preservation program requires knowledge of the perfo...

  15. Serviceable pavement marking retroreflectivity levels : technical report.

    Science.gov (United States)

    2009-03-01

    This research addressed an array of issues related to measuring pavement markings retroreflectivity, factors : related to pavement marking performance, subjective evaluation process, best practices for using mobile : retroreflectometers, sampling pav...

  16. An approach to pavement management in Virginia.

    Science.gov (United States)

    1981-01-01

    The report summarizes the objectives and benefits of formal pavement management systems and outlines an approach believed by the author to be practical for Virginia. The management of Virginia interstate pavements and a proposed random-sampling plan ...

  17. Sustainable concrete pavements : a manual of practice.

    Science.gov (United States)

    2011-08-01

    Developed as a more detailed follow-up to a 2009 briefing document, Building Sustainable Pavement with Concrete, this guide provides a clear, concise, and cohesive discussion of pavement sustainability concepts and of recommended practices for maximi...

  18. Pavement performance evaluation, phase II : data collection.

    Science.gov (United States)

    2008-12-01

    Phase I and II of this study tested approximately 1500 rehabilitated pavements (asphalt and PCC) : throughout the State. These pavements ranged from 5 to 15 years old and were intended to develop a : snapshot of how various rehabilitations were perfo...

  19. Quantifying Evaporation in a Permeable Pavement System

    Science.gov (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  20. Vacuum Bellows, Vacuum Piping, Cryogenic Break, and Copper Joint Failure Rate Estimates for ITER Design Use

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader

    2010-06-01

    The ITER international project design teams are working to produce an engineering design in preparation for construction of the International Thermonuclear Experimental Reactor (ITER) tokamak. During the course of this work, questions have arisen in regard to safety barriers and equipment reliability as important facets of system design. The vacuum system designers have asked several questions about the reliability of vacuum bellows and vacuum piping. The vessel design team has asked about the reliability of electrical breaks and copper-copper joints used in cryogenic piping. Research into operating experiences of similar equipment has been performed to determine representative failure rates for these components. The following chapters give the research results and the findings for vacuum system bellows, power plant stainless steel piping (amended to represent vacuum system piping), cryogenic system electrical insulating breaks, and copper joints.

  1. Generating enhanced site topography data to improve permeable pavement performance assessment methods - presentation

    Science.gov (United States)

    Permeable pavement surfaces are infiltration based stormwater control measures (SCM) commonly applied in parking lots to decrease impervious area and reduce runoff volume. Many are not optimally designed however, as little attention is given to draining a large enough contributin...

  2. Selection of pavement foundation geomaterials for the construction of a new runway

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2011-07-01

    Full Text Available The selection of foundation geomaterials including base/subbase unbound granular aggregate is critical for the design of flexible airfield pavements in the United States. These materials must meet the Federal Aviation Administration (FAA) selection...

  3. PCR evaluation : considering transition from manual to semi-automated pavement distress collection and analysis.

    Science.gov (United States)

    2013-07-01

    This study is designed to assist the Ohio Department of Transportation (ODOT) in determining : whether transitioning from manual to state-of the-practice semi-automated pavement distress : data collection is feasible and recommended. Statistical and ...

  4. Relating surface texture of rigid pavement with noise and skid resistance

    Science.gov (United States)

    2004-01-01

    Although pavements are initially designed to be durable for specified traffic loads, they must also satisfy other functional characteristics, primarily safety, smoothness and comfort (noise generation). Frequently, there are necessary trade-offs for ...

  5. Cone penetrometer equipped with piezoelectric sensors for measurement of soil stiffness in highway pavement.

    Science.gov (United States)

    2005-11-01

    The stiffness (elastic modulus and shear modulus) and Poisson's ratio of the base and sublayers are important parameters in the design and quality assurance during construction of highway pavements. The new highway construction guide proposed by AASH...

  6. Common Characteristics of Good and Poorly Performing PCC Pavements

    Science.gov (United States)

    1998-01-01

    This report documents the analysis and findings of a study to identify the site conditions and design/construction features of concrete pavements (JPCP, JRCP, CRCP) that lead to good performance and those that lead to poor performance. Data from Long...

  7. Texas perpetual pavements : experience overview and the way forward.

    Science.gov (United States)

    2010-07-01

    Since 2001, the State of Texas has been designing and constructing perpetual pavements on some of its heavily : trafficked highways where the expected 20-year truck-traffic estimate of 18 kip ESALs is in excess of 30 million. To : date, there are 10 ...

  8. Evaluation of the life shortening of flexible pavements | Bavandpour ...

    African Journals Online (AJOL)

    One of the reasons of life shortening of pavements operation is designing regardless of their administrative facts. The amount of transferred load between the layers depends on various factors such as the degree of adhesion and internal friction between the layers. If these layers limit by using proper bonding and sufficient ...

  9. Influence of preparation design on failure risks of ceramic inlays: a finite element analysis.

    Science.gov (United States)

    Ona, Masahiro; Watanabe, Chie; Igarashi, Yoshimasa; Wakabayashi, Noriyuki

    2011-08-01

    To assess the influence of preparation design on failure risk of ceramic inlays by means of finite element (FE) analysis. Both 2D and 3D models of the maxillary first premolar were constructed. MOD ceramic inlays were designed with an isthmus width of 1.5 to 5.0 mm and a minimum thickness of 1 to 3 mm. Occlusal contact motion and debonding at the tooth/ceramic adhesive interface were simulated in 2D models by downward displacement of a ceramic ball (1.5 mm in diameter) onto the central groove. The stress distributions within the inlays and at the interface were analyzed using 3D models. A maximum occlusal load of 250 N was assumed. The maximum principal stress at the base of the inlays was constant among models of different isthmus widths, although it decreased considerably as inlay thickness increased from 1 mm to 2 mm. The maximum shear stress at the adhesive interface increased as the width of the inlay decreased and the distance between the occlusal contact and the margin decreased to 0.3 mm or less. The maximum principal stress on the occlusal surface was relatively low and insensitive to inlay design; however, it was increased by a simulated adhesive failure. The failure risk at the base of the inlay is minimized by increasing the minimum inlay thickness. As the occlusal contact becomes close to the margin, the adhesive failure risk is increased, potentially leading to an increase in risk of fracture on the occlusal surface.

  10. Failure mode analysis of preliminary design of ITER divertor impurity monitor

    International Nuclear Information System (INIS)

    Kitazawa, Sin-iti; Ogawa, Hiroaki

    2016-01-01

    Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • Failure mode of DIM was prepared for RAMI analysis. • RAMI analysis on DIM was performed to reduce technical risks. - Abstract: The objective of the divertor impurity influx monitor (DIM) for ITER is to measure the parameters of impurities and hydrogen isotopes (tritium, deuterium, and hydrogen) in divertor plasma using visible and UV spectroscopic techniques in the 200–1000 nm wavelength range. In ITER, special provisions are required to ensure accuracy and full functionality of the diagnostic components under harsh conditions (high temperature, high magnetic field, high vacuum condition, and high radiation field). Japan Domestic Agency is preparing the preliminary design of the ITER DIM system, which will be installed in the upper, equatorial and lower ports. The optical and mechanical designs of the DIM are conducted to fit ITER’s requirements. The optical and mechanical designs meet the requirements of spatial resolution. Some auxiliary systems were examined via prototyping. The preliminary design of the ITER DIM system was evaluated by RAMI analysis. The availability of the designed system is adequately high to satisfy the project requirements. However, some equipment does not have certain designs, and this may cause potential technical risks. The preliminary design should be modified to reduce technical risks and to prepare the final design.

  11. Failure mode analysis of preliminary design of ITER divertor impurity monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Sin-iti, E-mail: kitazawa.siniti@qst.go.jp; Ogawa, Hiroaki

    2016-11-15

    Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • Failure mode of DIM was prepared for RAMI analysis. • RAMI analysis on DIM was performed to reduce technical risks. - Abstract: The objective of the divertor impurity influx monitor (DIM) for ITER is to measure the parameters of impurities and hydrogen isotopes (tritium, deuterium, and hydrogen) in divertor plasma using visible and UV spectroscopic techniques in the 200–1000 nm wavelength range. In ITER, special provisions are required to ensure accuracy and full functionality of the diagnostic components under harsh conditions (high temperature, high magnetic field, high vacuum condition, and high radiation field). Japan Domestic Agency is preparing the preliminary design of the ITER DIM system, which will be installed in the upper, equatorial and lower ports. The optical and mechanical designs of the DIM are conducted to fit ITER’s requirements. The optical and mechanical designs meet the requirements of spatial resolution. Some auxiliary systems were examined via prototyping. The preliminary design of the ITER DIM system was evaluated by RAMI analysis. The availability of the designed system is adequately high to satisfy the project requirements. However, some equipment does not have certain designs, and this may cause potential technical risks. The preliminary design should be modified to reduce technical risks and to prepare the final design.

  12. An Investigation of Geography and Climate Induced Distresses Patterns on Airfield Pavements at US Air Force Installations

    Directory of Open Access Journals (Sweden)

    Lauren K. Sahagun

    2017-01-01

    Full Text Available This study investigated climate induced distresses patterns on airfield pavements at US Air Force installations. A literature review and surveys of Pavement Condition Index indicated that the predominant factor contributing to the development of pavement distress was climate. Results suggested that, within each type of pavement distress, a geographic pattern exists which is strongly correlated to conventional US climate zones. The US Air Force Roll-Up Database, housing over 50,000 records of pavement distress data, was distilled using a process designed to combine similar distresses while accounting for age and size of samples. The process reduced the data to a format that could be used to perform krig analysis and to develop pavement behavior models for runways built with asphalt cement (AC and Portland cement concrete (PCC. Regression and krig analyses were conducted for each distress type to understand distress behavior among climate zones. Combined regression and krig analyses provided insight into the overall pavement behavior for AC and PCC runways and illustrated which climate zone was more susceptible to specific pavement distresses. Distress behavior tends to be more severe in the eastern US for AC and in the western US for PCC runway pavements, respectively.

  13. In-Vessel Coil Material Failure Rate Estimates for ITER Design Use

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader

    2013-01-01

    The ITER international project design teams are working to produce an engineering design for construction of this large tokamak fusion experiment. One of the design issues is ensuring proper control of the fusion plasma. In-vessel magnet coils may be needed for plasma control, especially the control of edge localized modes (ELMs) and plasma vertical stabilization (VS). These coils will be lifetime components that reside inside the ITER vacuum vessel behind the blanket modules. As such, their reliability is an important design issue since access will be time consuming if any type of repair were necessary. The following chapters give the research results and estimates of failure rates for the coil conductor and jacket materials to be used for the in-vessel coils. Copper and CuCrZr conductors, and stainless steel and Inconel jackets are examined.

  14. Evaluation of a new experimental test procedure to more accurately determine the surface infiltration rate of permeable pavement systems

    NARCIS (Netherlands)

    Lucke, T.; Boogaard, F.; Van den Ven, F.

    2014-01-01

    Permeable pavements are specifically designed to promote the infiltration of stormwater through the paving surface in order to reduce run-off volumes and to improve water quality by removing sediment and other pollutants. However, research has shown that permeable pavements can become clogged over

  15. Pavement noise measurements in Poland

    Science.gov (United States)

    Zofka, Ewa; Zofka, Adam; Mechowski, Tomasz

    2017-09-01

    The objective of this study is to investigate the feasibility of the On-Board Sound Intensity (OBSI) system to measure tire-pavement noise in Poland. In general, sources of noise emitted by the modern vehicles are the propulsion noise, aerodynamic resistance and noise generated at the tire-pavement interface. In order to capture tire-pavement noise, the OBSI system uses a noise intensity probe installed in the close proximity of that interface. In this study, OBSI measurements were performed at different types of pavement surfaces such as stone mastic asphalt (SMA), regular asphalt concrete (HMA) as well as Portland cement concrete (PCC). The influence of several necessary OBSI measurement conditions were recognized as: testing speed, air temperature, tire pressure and tire type. The results of this study demonstrate that the OBSI system is a viable and robust tool that can be used for the quality evaluation of newly built asphalt pavements in Poland. It can be also applied to generate reliable input parameters for the noise propagation models that are used to assess the environmental impact of new and existing highway corridors.

  16. Kidney (Renal) Failure

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Kidney Failure Kidney failure, also known as renal failure, is ... is kidney failure treated? What is kidney (renal) failure? The kidneys are designed to maintain proper fluid ...

  17. A probabilistic model for failure design of glass plates in buildings

    Directory of Open Access Journals (Sweden)

    Fernández Canteli, Alfonso

    1996-06-01

    Full Text Available A model for the design of glass plates to failure is presented, which, based on the theory of plates with gross deformations for the calculation of the stress state as well as on the empirical flaws statistical distribution in the glass surface, applies fracture Mechanics criteria to establish a probabilistic prediction of failure. The validity of the model has been experimentally proved for plates with different thicknesses and geometric characteristics.

    Se propone un modelo para el dimensionamiento a rotura de acristalamientos de vidrio, que, partiendo del estado tensional, obtenido mediante la teoría de placas con grandes deformaciones, y de la distribución empírica de defectos superficiales en el vidrio, utiliza criterios de Mecánica de la Fractura para predecir probabilísticamente la rotura. La validez del modelo ha podido ser contrastada experimentalmente en placas de diferentes espesores y con variadas relaciones geométricas.

  18. Innovative Clinical Trial Designs for Precision Medicine in Heart Failure with Preserved Ejection Fraction.

    Science.gov (United States)

    Shah, Sanjiv J

    2017-06-01

    A major challenge in the care of patients with heart failure and preserved ejection fraction (HFpEF) is the lack of proven therapies due to disappointing results from randomized controlled trials (RCTs). The heterogeneity of the HFpEF syndrome and the use of conventional RCT designs are possible reasons underlying the failure of these trials. There are several factors-including the widespread adoption of electronic health records, decreasing costs of obtaining high-dimensional data, and the availability of a wide variety of potential therapeutics-that have evolved to enable more innovative clinical trial designs in HFpEF. Here, we review the current landscape of HFpEF RCTs and present several innovative RCT designs that could be implemented in HFpEF, including enrichment trials, adaptive trials, umbrella trials, basket trials, and machine learning-based trials (including examples for each). Our hope is that the description of the aforementioned innovative trial designs will stimulate new approaches to clinical trials in HFpEF.

  19. Geo synthetic-reinforced Pavement systems

    International Nuclear Information System (INIS)

    Zornberg, J. G.

    2014-01-01

    Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

  20. Evaluation of Asphalt Pavement Distresses in Main Roadways in Al-Diwaniyah City

    Directory of Open Access Journals (Sweden)

    Zaid Ali Kadhim

    2017-12-01

    Full Text Available Asphalt pavement influenced by many factors effect on its performance and serviceability, factors like excessive traffic loads, temperatures, water, design and execution mistakes, and lack of maintenance, these make the Pavement has fast deteriorated with time. The temperature in Iraq exceeded the 50o c, and without controlling on traffic loads and no plans in maintenance management lead to appear severity distresses in most of roads in Iraq. Road maintenance management system improvement leads to reduce time and cost and the pavement condition survey is taking a big role in the pavement management at network level provides the information for pavement performance. Three different main roads were selected in the city of Diwaniyah and the distresses amount was surveyed by using two methods: present serviceability rating and pavement condition index to determine the pavement performance. 10 defects were identified in the asphalt pavement out of (19 defects mentioned by the PCI method, the cracks are the densest distresses in the pavement followed by the rutting and potholes and the rest of the distresses are less dense, all of which are due to poor mix design and poorly implemented. The results showed that the users' opinions of the studied roads were affected mainly by the roads roughness, the PSR values ​​gave a fair rating of the studied roads while the PCI method gave a poor rating that is meaning Iraqis are more bearing to the hardships they face while using the roads. A periodic survey shall be conducted on the transportation network which shall be consisting of a database.

  1. Sensitivity analysis of asphalt-pavement structure dynamic responses under heavy load

    Directory of Open Access Journals (Sweden)

    ZHANG Lijuan

    2015-04-01

    Full Text Available With the 3-Dimensional finite-element dynamic model,the influence of axis-load,axis-speed,and pavement structure parameters on dynamic performance of pavement structure is studied.The results show that with the increase in load,the dynamic response of pavement is nearly proportional to axis-load and increases noticeably;Axis-speed influences the dynamic response to some extent.With the increase of axis-speed,dynamic response of pavement structure increases firstly.With axis-speed further increasing,dynamic response of pavement structure then decreases gradually.For fatigue failure,the influence of heavy-load with common moving speed is much greater than that of static load.Among the pavement structure parameters,thickness of surface-layer has a significant effect on shear stress and the compression stress at road surface.Subgrade modulus has a significant effect on road surface deflection,tensile stress at the bottom of subbase,and compression-strain at the top of subgrade.

  2. Use of noncontact sensors for paving operations on airport pavements

    Science.gov (United States)

    Lenngren, Carl A.

    1999-01-01

    The Swedish National Road Administration has been using a laser range finder system for assessing longitudinal and transversa profiles of pavements for a number of years. The Civil Administration has expressed interest in trying automated methods for surveying airfield runways. Regardless of sampling method, the data re used as input for computer aided design of new pavement surfaces. Typically, the output will consist of tables and maps of where to pave and mill the old pavement surface. Adjusting an old surface to perfectly smooth standards may require continuously changing the new pavement layer thickness. Traditionally, this was often carried out with mechanical devices, usually in direct touch with a wire. Some manufacturers now offer non-contact devices for pavers such as ultra sound sensors as an alternative to the mechanical sensors thus eliminating the need for setting up sires. The method was tested in late 1997 after the output data were converted for a design to be read directly by a paver control unit. A larger test was done in the summer of 1998. The results were promising and the Royal Swedish Fortifications Administration decided to try the method on a taxiway in 1999. The present paper describes some of the experiences obtained with this method and computer controlled equipment in general.

  3. Failures to further developing orphan medicinal products after designation granted in Europe: an analysis of marketing authorisation failures and abandoned drugs.

    Science.gov (United States)

    Giannuzzi, Viviana; Landi, Annalisa; Bosone, Enrico; Giannuzzi, Floriana; Nicotri, Stefano; Torrent-Farnell, Josep; Bonifazi, Fedele; Felisi, Mariagrazia; Bonifazi, Donato; Ceci, Adriana

    2017-09-11

    The research and development process in the field of rare diseases is characterised by many well-known difficulties, and a large percentage of orphan medicinal products do not reach the marketing approval.This work aims at identifying orphan medicinal products that failed the developmental process and investigating reasons for and possible factors influencing failures. Drugs designated in Europe under Regulation (European Commission) 141/2000 in the period 2000-2012 were investigated in terms of the following failures: (1) marketing authorisation failures (refused or withdrawn) and (2) drugs abandoned by sponsors during development.Possible risk factors for failure were analysed using statistically validated methods. This study points out that 437 out of 788 designations are still under development, while 219 failed the developmental process. Among the latter, 34 failed the marketing authorisation process and 185 were abandoned during the developmental process. In the first group of drugs (marketing authorisation failures), 50% reached phase II, 47% reached phase III and 3% reached phase I, while in the second group (abandoned drugs), the majority of orphan medicinal products apparently never started the development process, since no data on 48.1% of them were published and the 3.2% did not progress beyond the non-clinical stage.The reasons for failures of marketing authorisation were: efficacy/safety issues (26), insufficient data (12), quality issues (7), regulatory issues on trials (4) and commercial reasons (1). The main causes for abandoned drugs were efficacy/safety issues (reported in 54 cases), inactive companies (25.4%), change of company strategy (8.1%) and drug competition (10.8%). No information concerning reasons for failure was available for 23.2% of the analysed products. This analysis shows that failures occurred in 27.8% of all designations granted in Europe, the main reasons being safety and efficacy issues. Moreover, the stage of development

  4. Probabilistic Design Analysis (PDA) Approach to Determine the Probability of Cross-System Failures for a Space Launch Vehicle

    Science.gov (United States)

    Shih, Ann T.; Lo, Yunnhon; Ward, Natalie C.

    2010-01-01

    Quantifying the probability of significant launch vehicle failure scenarios for a given design, while still in the design process, is critical to mission success and to the safety of the astronauts. Probabilistic risk assessment (PRA) is chosen from many system safety and reliability tools to verify the loss of mission (LOM) and loss of crew (LOC) requirements set by the NASA Program Office. To support the integrated vehicle PRA, probabilistic design analysis (PDA) models are developed by using vehicle design and operation data to better quantify failure probabilities and to better understand the characteristics of a failure and its outcome. This PDA approach uses a physics-based model to describe the system behavior and response for a given failure scenario. Each driving parameter in the model is treated as a random variable with a distribution function. Monte Carlo simulation is used to perform probabilistic calculations to statistically obtain the failure probability. Sensitivity analyses are performed to show how input parameters affect the predicted failure probability, providing insight for potential design improvements to mitigate the risk. The paper discusses the application of the PDA approach in determining the probability of failure for two scenarios from the NASA Ares I project

  5. Design of a recovery scheme for the Galileo spacecraft in the event of nutation damper failure

    Science.gov (United States)

    Eke, Fidelis O.

    1988-01-01

    This paper discusses the design and testing of remedial measures that can be taken to achieve reasonable nutation damping of the Galileo spacecraft in the event of failure of its boom damper in flight. One scheme exploits the effects of payload motion on the nutational stability of a spinning spacecraft. This scheme demands that the spacecraft motion compensation algorithm be enabled with the scan platform bore sight pointed in a well chosen direction to produce rapid damping of spacecraft nutation. A second method suggested for nutation damping is a thruster-based open loop control algorithm, utilizing a pair of thrusters as actuators.

  6. Rationale and study design of the INcrease Of Vagal TonE in Heart Failure study : INOVATE-HF

    NARCIS (Netherlands)

    Hauptman, Paul J.; Schwartz, Peter J.; Gold, Michael R.; Borggrefe, Martin; Van Veldhuisen, Dirk J.; Starling, Randall C.; Mann, Douglas L.

    Background Imbalance between the parasympathetic and sympathetic nervous systems is a recognized contributor to progression of chronic heart failure. Current therapy with beta adrenergic antagonists is designed to moderate the up-regulation of norepinephrine and sympathetic effects; however, to

  7. Mechanical Response Analysis of Long-life Asphalt Pavement Structure of Yunluo High-speed on the Semi-rigid Base

    Science.gov (United States)

    Liu, Feng; Wu, Chuanhai; Xu, Xinquan; Li, Hao; Wang, Zhixiang

    2018-01-01

    In order to grasp the rule of the strain change of the semi-rigid asphalt pavement structure under the FWD load and provide a reliable theoretical and practical basis for the design of the pavement structure, based on the test section of Guangdong Yunluo expressway, taking FWD as the loading tool, by using the finite element analysis software ANSYS, the internal variation rules of each pavement structural layer were obtained. Based on the results of the theoretical analysis, the measured strain sensor was set up in the corresponding layer of the pavement structure, and the strain test plan was determined. Based on the analysis of the strain data obtained from several structural layers and field monitoring, the rationality of the type pavement structure and the strain test scheme were verified, so as to provide useful help for the design and the maintenance of the pavement structure.

  8. Life-Cycle Environmental and Economic Assessment of Using Recycled Materials for Asphalt Pavements

    OpenAIRE

    Horvath, Arpad

    2003-01-01

    The public, industry and governments have become increasingly interested in green design and engineering as approaches towards better environmental quality and sustainable development. Pavement construction is one of the largest consumers of natural resources. Recycling of pavements represents an important opportunity to save the mining and use of virgin materials, conserve energy, divert materials away from landfills, and save scarce tax dollars. How much pollution, energy, natural resources...

  9. Comparison of winter temperature profiles in asphalt and concrete pavements.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) determine which pavement type, asphalt or concrete, has : higher surface temperatures in winter and 2) compare the subsurface temperatures under asphalt and : concrete pavements to determine the pavement typ...

  10. Minnesota Local Agency Pavement Marking : Mining Existing Data

    Science.gov (United States)

    2017-11-01

    Pavement marking is important for safety. Maximizing pavement marking performance in terms of increased retroreflectivity, within limited budget constraints, allows agencies to make better decisions toward providing more effective pavement marking pe...

  11. Effects of Interlocking and Supporting Conditions on Concrete Block Pavements

    Science.gov (United States)

    Mahapatra, Geetimukta; Kalita, Kuldeep

    2018-02-01

    Concrete Block Paving (CBP) is widely used as wearing course in flexible pavements, preferably under light and medium vehicular loadings. Construction of CBP at site is quick and easy in quality control. Usually, flexible pavement design philosophy is followed in CBP construction, though it is structurally different in terms of small block elements with high strength concrete and their interlocking aspects, frequent joints and discontinuity, restrained edge etc. Analytical solution for such group action of concrete blocks under loading in a three dimensional multilayer structure is complex and thus, the need of conducting experimental studies is necessitated for extensive understanding of the load—deformation characteristics and behavior of concrete blocks in pavement. The present paper focuses on the experimental studies for load transfer characteristics of CBP under different interlocking and supporting conditions. It is observed that both interlocking and supporting conditions affect significantly on the load transfer behavior in CBP structures. Coro-lock block exhibits better performance in terms of load carrying capacity and distortion behavior under static loads. Plate load tests are performed over subgrade, granular sub-base (GSB), CBP with and without GSB using different block shapes. For an example case, the comparison of CBP with conventional flexible pavement section is also presented and it is found that CBP provides considerable benefit in terms of construction cost of the road structure.

  12. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.D.K.

    1989-01-01

    This article describes a phenomenon known all over Africa, for which there is no really satisfactory term in English but which is summed up in the French term 'radio trottoir', literally 'pavement radio'. It may be defined as the popular and unofficial discussion of current affairs in Africa,

  13. The Concrete and Pavement Challenge

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  14. Climate change, energy, sustainability and pavements

    International Nuclear Information System (INIS)

    Gopalakrishnan, Kasthurirangan; Steyn, Wynand JvdM; Harvey, John

    2014-01-01

    Provides an integrated perspective on understanding the impacts of climate change, energy and sustainable development on transportation infrastructure systems. Presents recent technological innovations and emerging concepts in the field of green and sustainable transportation infrastructure systems with a special focus on highway and airport pavements. Written by leading experts in the field. Climate change, energy production and consumption, and the need to improve the sustainability of all aspects of human activity are key inter-related issues for which solutions must be found and implemented quickly and efficiently. To be successfully implemented, solutions must recognize the rapidly changing socio-techno-political environment and multi-dimensional constraints presented by today's interconnected world. As part of this global effort, considerations of climate change impacts, energy demands, and incorporation of sustainability concepts have increasing importance in the design, construction, and maintenance of highway and airport pavement systems. To prepare the human capacity to develop and implement these solutions, many educators, policy-makers and practitioners have stressed the paramount importance of formally incorporating sustainability concepts in the civil engineering curriculum to educate and train future civil engineers well-equipped to address our current and future sustainability challenges. This book will prove a valuable resource in the hands of researchers, educators and future engineering leaders, most of whom will be working in multidisciplinary environments to address a host of next-generation sustainable transportation infrastructure challenges.

  15. Climate change, energy, sustainability and pavements

    Energy Technology Data Exchange (ETDEWEB)

    Gopalakrishnan, Kasthurirangan [Iowa State Univ., Ames, IA (United States). Dept. of Civil, Construction and Environmental Engineering; Steyn, Wynand JvdM [Pretoria Univ. (South Africa). Dept. of Civil Engineering; Harvey, John (ed.) [California Univ., Davis, CA (United States). Dept. of Civil and Environmental Engineering

    2014-07-01

    Provides an integrated perspective on understanding the impacts of climate change, energy and sustainable development on transportation infrastructure systems. Presents recent technological innovations and emerging concepts in the field of green and sustainable transportation infrastructure systems with a special focus on highway and airport pavements. Written by leading experts in the field. Climate change, energy production and consumption, and the need to improve the sustainability of all aspects of human activity are key inter-related issues for which solutions must be found and implemented quickly and efficiently. To be successfully implemented, solutions must recognize the rapidly changing socio-techno-political environment and multi-dimensional constraints presented by today's interconnected world. As part of this global effort, considerations of climate change impacts, energy demands, and incorporation of sustainability concepts have increasing importance in the design, construction, and maintenance of highway and airport pavement systems. To prepare the human capacity to develop and implement these solutions, many educators, policy-makers and practitioners have stressed the paramount importance of formally incorporating sustainability concepts in the civil engineering curriculum to educate and train future civil engineers well-equipped to address our current and future sustainability challenges. This book will prove a valuable resource in the hands of researchers, educators and future engineering leaders, most of whom will be working in multidisciplinary environments to address a host of next-generation sustainable transportation infrastructure challenges.

  16. Improved performance evaluation of road pavements by using measured tyre loading

    CSIR Research Space (South Africa)

    Maina, JW

    2008-11-01

    Full Text Available tyre stresses and their different shapes. It was also found that single wide-base tyres introduce more than double the potential for failure compared with the dual tyre configuration on the same pavement. Furthermore, this study demonstrates that under-inflated...

  17. Feasibility of reclaimed asphalt pavement as aggregate in portland cement concrete pavements.

    Science.gov (United States)

    2013-11-01

    This research effort was focused on evaluating the feasibility of using minimally processed reclaimed : asphalt pavement (RAP) as aggregate replacement in concrete pavements. This research demonstrated : that concretes with up to 50 percent of the fi...

  18. Comparison of accelerated pavement test results with long term pavement behaviour and performance

    CSIR Research Space (South Africa)

    Jooste, FJ

    1997-08-01

    Full Text Available The aim of this study was to investigate the following:how accelerated pavement testing predictions compare with actual road behaviour and performance the relative influences of load and environmental factors on pavement deterioration and how well...

  19. An integrated pavement data management and feedback system (PAMS) : evaluation of pavement condition rating procedure.

    Science.gov (United States)

    1984-08-01

    This report describes an evaluation of a method for use in the Highway Needs Study pavement condition rating. The methods by which the Department generates and manages pavement condition data in the overall process of providing a network of highways ...

  20. Integration and Evaluation of Automated Pavement Distress Data in INDOT’s Pavement Management System

    Science.gov (United States)

    2017-05-01

    This study was in two parts. The first part established and demonstrated a framework for pavement data integration. This is critical for fulfilling QC/QA needs of INDOTs pavement management system, because the precision of the physical location re...

  1. Long-term pavement performance information management system : pavement performance database user reference guide

    Science.gov (United States)

    2003-11-01

    This document provides information to aid in understanding and using the Long-Term Pavement Performance (LTPP) program pavement performance database. This document provides an introduction to the structure of the LTPP program, the relational structur...

  2. Application of the portable pavement seismic analyser (PSPA) for pavement analysis

    CSIR Research Space (South Africa)

    Steyn, WJVDM

    2007-07-01

    Full Text Available of pavement types, including Long-Term Pavement Performance (LTPP) sections and Heavy Vehicle Simulator (HVS) test sites. The data are analysed for repeatability, variability, isotropy, and ranges of seismic stiffness values. Information is provided...

  3. MoDOT pavement preservation research program volume IV, pavement evaluation tools-data collection methods.

    Science.gov (United States)

    2015-10-01

    The overarching goal of the MoDOT Pavement Preservation Research Program, Task 3: Pavement Evaluation Tools Data : Collection Methods was to identify and evaluate methods to rapidly obtain network-level and project-level information relevant to :...

  4. Effect of mineral additives on structure and properties of concrete for pavements

    Science.gov (United States)

    Sobol, Khrystyna; Markiv, Taras; Hunyak, Oleksii

    2017-12-01

    Concrete pavements is an attractive alternative to asphalt pavements because of its lower cost and higher durability. Major contribution to sustainable development can be made by partial replacement of cement in concrete pavement with supplementary cementitious materials of different nature and origin. In this paper, the effect of natural zeolite and perlite additives in complex with chemical admixtures on the structure and properties of concrete for pavement was studied. Compressive and flexural strength test was used to study the mechanical behavior of designed concrete under load. Generally, the compressive strength of both control concrete and concrete containing mineral additives levels at the later ages of hardening. The microstructure analysis of concrete with mineral additives of different nature activity showed the formation of additional amount of hydration products such as tobermorite type calcium hydrosilicate which provide self-reinforcement of hardening concrete system.

  5. The use of accelerometers in the pavement performance monitoring and analysis

    International Nuclear Information System (INIS)

    Ryynaenen, T; Belt, J; Pellinen, T

    2010-01-01

    This study investigated the use of sensor technology to enhance the management of highway infrastructure. With the help of monitoring data, it is possible to assess the current analytical pavement analysis method, which is based on multi-layered elastic analysis, and, thus enhance the pavement design practices in use. Pavement response was measured using different sensors, installed at various depths. Most promising sensors for the continuous monitoring purposes were the accelerometers. The drawback of these sensors is that the measured quantity is acceleration, which must be converted to the deflection via mathematical integration. In this paper some issues related to the manipulation of accelerometer data is presented and discussed, in addition of the discussion of the calculated and measured pavement response.

  6. The use of accelerometers in the pavement performance monitoring and analysis

    Science.gov (United States)

    Ryynänen, T.; Pellinen, T.; Belt, J.

    2010-06-01

    This study investigated the use of sensor technology to enhance the management of highway infrastructure. With the help of monitoring data, it is possible to assess the current analytical pavement analysis method, which is based on multi-layered elastic analysis, and, thus enhance the pavement design practices in use. Pavement response was measured using different sensors, installed at various depths. Most promising sensors for the continuous monitoring purposes were the accelerometers. The drawback of these sensors is that the measured quantity is acceleration, which must be converted to the deflection via mathematical integration. In this paper some issues related to the manipulation of accelerometer data is presented and discussed, in addition of the discussion of the calculated and measured pavement response.

  7. Effect of mineral additives on structure and properties of concrete for pavements

    Directory of Open Access Journals (Sweden)

    Sobol Khrystyna

    2017-12-01

    Full Text Available Concrete pavements is an attractive alternative to asphalt pavements because of its lower cost and higher durability. Major contribution to sustainable development can be made by partial replacement of cement in concrete pavement with supplementary cementitious materials of different nature and origin. In this paper, the effect of natural zeolite and perlite additives in complex with chemical admixtures on the structure and properties of concrete for pavement was studied. Compressive and flexural strength test was used to study the mechanical behavior of designed concrete under load. Generally, the compressive strength of both control concrete and concrete containing mineral additives levels at the later ages of hardening. The microstructure analysis of concrete with mineral additives of different nature activity showed the formation of additional amount of hydration products such as tobermorite type calcium hydrosilicate which provide self-reinforcement of hardening concrete system.

  8. The numerical model for parametric studies of forest haul roads pavements

    Directory of Open Access Journals (Sweden)

    Lenka Ševelová

    2010-01-01

    Full Text Available Forest roads pavement structures are considered to be low volume roads. These roads serve as a mean of transport of wood and people. Besides they are currently often used for recreational purpose. The construction of the pavements should be suitable for forest transportation irrespective of their low bearing capacity. These pavement structures are very specific for special unbound materials that are used in their construction. To meet the requirements of the pavement designs and simulation analysis the FEM model in the software ANSYS was created.This paper compares two material models used for the description of the behaviour of unbound materials. The first is linear elastic according to Hook theory (H model and the second one is nonlinear plastic model Drucker-Prager (D–P model. ANSYS software has been used to create flexible model based on the parametrers of variable principle. The flexible model is parametric to realize repeated calculations useful for optimization analysis.

  9. Low Carbon-Oriented Optimal Reliability Design with Interval Product Failure Analysis and Grey Correlation Analysis

    Directory of Open Access Journals (Sweden)

    Yixiong Feng

    2017-03-01

    Full Text Available The problem of large amounts of carbon emissions causes wide concern across the world, and it has become a serious threat to the sustainable development of the manufacturing industry. The intensive research into technologies and methodologies for green product design has significant theoretical meaning and practical value in reducing the emissions of the manufacturing industry. Therefore, a low carbon-oriented product reliability optimal design model is proposed in this paper: (1 The related expert evaluation information was prepared in interval numbers; (2 An improved product failure analysis considering the uncertain carbon emissions of the subsystem was performed to obtain the subsystem weight taking the carbon emissions into consideration. The interval grey correlation analysis was conducted to obtain the subsystem weight taking the uncertain correlations inside the product into consideration. Using the above two kinds of subsystem weights and different caution indicators of the decision maker, a series of product reliability design schemes is available; (3 The interval-valued intuitionistic fuzzy sets (IVIFSs were employed to select the optimal reliability and optimal design scheme based on three attributes, namely, low carbon, correlation and functions, and economic cost. The case study of a vertical CNC lathe proves the superiority and rationality of the proposed method.

  10. Prediction of performance and evaluation of flexible pavement rehabilitation strategies

    Directory of Open Access Journals (Sweden)

    Kang-Won Wayne Lee

    2017-04-01

    Full Text Available Five test sections with different additives and strategies were established to rehabilitate a State-maintained highway more effectively in Rhode Island (RI: control, calcium chloride, asphalt emulsion, Portland cement and geogrid. Resilient moduli of subgrade soils and subbase materials before and after full depth rehabilitation were employed as input parameters to predict the performance of pavement structures using AASHTOWare Pavement ME Design (Pavement ME software in terms of rutting, cracking and roughness. It was attempted to use Level 1 input (which includes traffic full spectrum data, climate data and structural layer properties for Pavement ME. Traffic data was obtained from a Weigh-in-Motion (WIM instrument and Providence station was used for collecting climatic data. Volumetric properties, dynamic modulus and creep compliance were used as input parameters for 19 mm (0.75 in. warm mix asphalt (WMA base and 12.5 mm (0.5 in. WMA surface layer. The results indicated that all test sections observed AC top-down (longitudinal cracking except Portland cement section which passed for all criteria. The order in terms of performance (best to worst for all test sections by Pavement ME was Portland cement, calcium chloride, control, geogrid, and asphalt emulsion. It was also observed that all test sections passed for both bottom up and top down fatigue cracking by increasing thickness of either of the two top asphalt layers. Test sections with five different base/subbase materials were evaluated in last two years through visual condition survey and measurements of deflection and roughness to confirm the prediction, but there was no serious distress and roughness. Thus these experiments allowed selecting the best rehabilitation/reconstruction techniques for the particular and/or similar highway, and a framework was formulated to select an optimal technique and/or strategy for future rehabilitation/reconstruction projects. Finally, guidelines for

  11. Cracking of open traffic rigid pavement

    OpenAIRE

    Niken Chatarina; Siswanto Yudi; Widodo; Tjahjono Elly

    2017-01-01

    The research is done by observing the growth of real structure cracking in Natar, Lampung, Indonesia compared to C. Niken’s et al research and literature study. The rigid pavement was done with open traffic system. There are two main crack types on Natar rigid pavement: cracks cross the road, and cracks spreads on rigid pavement surface. The observation of cracks was analyzed by analyzing material, casting, curing, loading and shrinkage mechanism. The relationship between these analysis and s...

  12. Optimal experimental designs for accelerated failure time with Type I and random censoring.

    Science.gov (United States)

    Rivas-López, María J; López-Fidalgo, Jesús; Campo, Rodrigo Del

    2014-09-01

    Proportional Hazards models have been widely used to analyze survival data. In many cases survival data do not verify the assumption of proportional hazards. An alternative to the PH models with more relaxed conditions are Accelerated Failure Time models. These models are fairly commonly used in the field of manufacturing, but they are more and more frequent for modeling clinical trial data. They focus on the direct effect of the explanatory variables on the survival function allowing an easier interpretation of the effect of the corresponding covariates on the survival time. Optimal experimental designs are computed in this framework for Type I and random arrival. The results are applied to clinical models used to prevent tuberculosis in Ugandan adults infected with HIV. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Partial Coefficient System for the Design of Monolithic Vertical Breakwaters Considering Sliding and Rupture Failure of the Foundation

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Christiani, Erik; Sørensen, John Dalsgaard

    1995-01-01

    The main object is to present a set of calibrated partial coefficients for monolithic vertical breakwater failure modes. A preliminary design of the monolithic breakwater will be considered, which will be designed from existing partial coefficients, documented in Eurocode 7 (1994). From this desi...

  14. Assessment of Load Capacity of the Airport Pavement Structure With the Use of the Acn-Pcn Method

    Directory of Open Access Journals (Sweden)

    Wesołowski Mariusz

    2014-12-01

    Full Text Available The structures of the airport pavements are designed for defined operational time, assuming the predicted intensity and structure of the air traffic. The safety of air operations conducted by aircrafts on airport pavements depends mostly on their load capacity and design. Therefore, the load capacity inspections should be performed periodically, as the information about the current operational condition of the airport pavement is the basis for decisions on types of aircrafts allowed for traffic, as well as traffic intensity and dates of renovation or modernization works.

  15. The use of reflective and permeable pavements as a potential practice for heat island mitigation and stormwater management

    International Nuclear Information System (INIS)

    Li, H; Harvey, J T; Holland, T J; Kayhanian, M

    2013-01-01

    To help address the built environmental issues of both heat island and stormwater runoff, strategies that make pavements cooler and permeable have been investigated through measurements and modeling of a set of pavement test sections. The investigation included the hydraulic and thermal performance of the pavements. The permeability results showed that permeable interlocking concrete pavers have the highest permeability (or infiltration rate, ∼0.5 cm s −1 ). The two permeable asphalt pavements showed the lowest permeability, but still had an infiltration rate of ∼0.1 cm s −1 , which is adequate to drain rainwater without generating surface runoff during most typical rain events in central California. An increase in albedo can significantly reduce the daytime high surface temperature in summer. Permeable pavements under wet conditions could give lower surface temperatures than impermeable pavements. The cooling effect highly depends on the availability of moisture near the surface layer and the evaporation rate. The peak cooling effect of watering for the test sections was approximately 15–35 °C on the pavement surface temperature in the early afternoon during summer in central California. The evaporative cooling effect on the pavement surface temperature at 4:00 pm on the third day (25 h after watering) was still 2–7 °C lower compared to that on the second day, without considering the higher air temperature on the third day. A separate and related simulation study performed by UCPRC showed that full depth permeable pavements, if designed properly, can carry both light-duty traffic and certain heavy-duty vehicles while retaining the runoff volume captured from an average California storm event. These preliminarily results indicated the technical feasibility of combined reflective and permeable pavements for addressing the built environment issues related to both heat island mitigation and stormwater runoff management. (letter)

  16. ANALYSIS OF STRESS STATE IN UPPER LAYER OF ROAD CONCRETE PAVEMENT WITH TEMPERATURE ACTION

    Directory of Open Access Journals (Sweden)

    M. K. Pshembaev

    2017-01-01

    Full Text Available While being operated auto-road pavements are subjected to intensive mechanical impacts, ultraviolet ray irradiation, freeze-thaw temperatures, freezing and thawing, drying and moistening. Due to these actions various types of pavement distresses appear on the road pavement. The most significant and dangerous type of distresses is micro-cracks on the road surface. One of the main reasons for their formation is an action of weather and climatic factors that initiate large changes in temperature of coating surface and occurrence of large temperature gradients in the upper layer. In this context while designing and operating auto-roads it is rather essential to investigate a stress state in road surface which is caused by temperature action. Purpose of the described investigations is to determine permissible temperature gradients for cement-concrete pavements that exclude formation of micro-cracks on their surface and thickness of damaged surface layer. Calculations of road pavement have been carried out at various laws for temperature distribution in its depth. A finite difference method realized in PARUS software has been used for studying a stress state of cement-concrete auto-roads. Regularities for distribution of stresses in cement-concrete pavement of auto-roads have been obtained at various surface temperatures. Permissible temperature gradients in the upper pavement layer have been determined and thickness of the layer where micro-cracks are formed has been assessed in the paper. Strength criterion based on the process of micro-crack formation and development in the concrete has been used for calculations. Risk of micro-crack formation on the auto-road pavement depends on material strength, conditions of plate fixing and temperature gradients.

  17. Evaluation of precut transverse cracks for an asphalt concrete pavement in interior Alaska (Moose Creek - Richardson Highway).

    Science.gov (United States)

    2015-08-01

    Road-width thermal cracks (major transverse cracks) are perhaps the most noticeable form of crack-related damage on AC pavements : throughout colder areas of Alaska. The main objective of this study is to recommend design strategies and construction ...

  18. User's guide: estimation of key PCC, base, subbase, and pavement engineering properties from routine tests and physical characteristics

    Science.gov (United States)

    2012-08-01

    Material characterization is a critical component of modern day pavement analysis, design, construction, quality : control/quality assurance, management, and rehabilitation. At each stage during the life of a project, the influence of : several funda...

  19. Cone penetrometer equipped with piezoelectric sensors for measurement of soil stiffness in highway pavement : executive summary report.

    Science.gov (United States)

    2005-11-01

    The stiffness (elastic modulus and shear modulus) and Poissons ratio of the base and : sublayers are important parameters in the design and quality assurance during construction of : highway pavements. During and after the construction of a paveme...

  20. GHG emission quantification for pavement construction projects using a process-based approach

    Directory of Open Access Journals (Sweden)

    Charinee Limsawasd

    2017-03-01

    Full Text Available Climate change and greenhouse gas (GHG emissions have attracted much attention for their impacts upon the global environment. Initiating of new legislation and regulations for control of GHG emissions from the industrial sectors has been applied to address this problem. The transportation industries, which include operation of road pavement and pavement construction equipment, are the highest GHG-emitting sectors. This study presents a novel quantification model of GHG emissions of pavement construction using process-based analysis. The model is composed of five modules that evaluate GHG emissions. These are: material production and acquisition, (2 material transport to a project site, (3 heavy equipment use, (4 on-site machinery use, and, (5 on-site electricity use. The model was applied to a hypothetical pavement project to compare the environmental impacts of flexible and rigid pavement types during construction. The resulting model can be used for evaluation of environmental impacts, as well as for designing and planning highway pavement construction.

  1. Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods.

    Science.gov (United States)

    Li, Hui; Kayhanian, Masoud; Harvey, John T

    2013-03-30

    Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Iterative User Interface Design for Automated Sequential Organ Failure Assessment Score Calculator in Sepsis Detection.

    Science.gov (United States)

    Aakre, Christopher Ansel; Kitson, Jaben E; Li, Man; Herasevich, Vitaly

    2017-05-18

    The new sepsis definition has increased the need for frequent sequential organ failure assessment (SOFA) score recalculation and the clerical burden of information retrieval makes this score ideal for automated calculation. The aim of this study was to (1) estimate the clerical workload of manual SOFA score calculation through a time-motion analysis and (2) describe a user-centered design process for an electronic medical record (EMR) integrated, automated SOFA score calculator with subsequent usability evaluation study. First, we performed a time-motion analysis by recording time-to-task-completion for the manual calculation of 35 baseline and 35 current SOFA scores by 14 internal medicine residents over a 2-month period. Next, we used an agile development process to create a user interface for a previously developed automated SOFA score calculator. The final user interface usability was evaluated by clinician end users with the Computer Systems Usability Questionnaire. The overall mean (standard deviation, SD) time-to-complete manual SOFA score calculation time was 61.6 s (33). Among the 24% (12/50) usability survey respondents, our user-centered user interface design process resulted in >75% favorability of survey items in the domains of system usability, information quality, and interface quality. Early stakeholder engagement in our agile design process resulted in a user interface for an automated SOFA score calculator that reduced clinician workload and met clinicians' needs at the point of care. Emerging interoperable platforms may facilitate dissemination of similarly useful clinical score calculators and decision support algorithms as "apps." A user-centered design process and usability evaluation should be considered during creation of these tools. ©Christopher Ansel Aakre, Jaben E Kitson, Man Li, Vitaly Herasevich. Originally published in JMIR Human Factors (http://humanfactors.jmir.org), 18.05.2017.

  3. The Rationale and Design of the Surgical Treatment for IsChemic Heart failure (STICH) Trial

    Science.gov (United States)

    Velazquez, Eric J.; Lee, Kerry L.; O’Connor, Christopher M.; Oh, Jae K.; Bonow, Robert O.; Pohost, Gerald M.; Feldman, Arthur M.; Mark, Daniel B.; Panza, Julio A.; Sopko, George; Rouleau, Jean L.; Jones, Robert H.

    2013-01-01

    Objectives The rationale and design of the Surgical Treatment for Ischemic Heart Failure (STICH) trial is described. Prior to STICH, <1000 ischemic cardiomyopathy patients had been studied in randomized comparisons of medical therapy (MED) versus coronary artery bypass graft surgery (CABG). Trial data reflect how these therapies were delivered over 20 years ago and do not indicate the relative benefits of MED versus CABG in contemporary practice. Methods Randomization of consenting patients with heart failure, left ventricular (LV) ejection fraction ≤0.35, and coronary artery disease is based on whether patients are judged by attending physicians to be candidates only for CABG or for MED or CABG. Patients eligible for surgical ventricular reconstruction (SVR) due to significant anterior wall akinesis or dyskinesis, but ineligible for MED are randomly assigned to CABG with or without SVR. Patients eligible for MED are randomly assigned between MED only and MED with CABG. Patients eligible for all 3 are randomly assigned evenly to MED only, MED and CABG, or MED and CABG and SVR. Major substudies will examine quality of life, cost-effectiveness, changes in LV volumes, impact of myocardial viability, selected biomarkers, and selected polymorphisms on treatment differences Conclusions STICH is an NHLBI-funded multicenter international randomized trial addressing 2 specific primary hypotheses: 1) CABG with intensive MED improves long-term survival compared with MED alone; and 2) in patients with anterior LV dysfunction, SVR to a more normal LV size plus CABG improves survival free of subsequent hospitalization for cardiac cause when compared with CABG alone. PMID:18023680

  4. Consideration of regional variations in climatic and soil conditions in the modified triaxial design method.

    Science.gov (United States)

    2008-11-01

    The Texas Department of Transportation (TxDOT) uses the modified triaxial design procedure to check : pavement designs from the flexible pavement system program. Since its original development more than : 50 years ago, little modification has been ma...

  5. Load Response Analysis of Asphalt Pavement

    Directory of Open Access Journals (Sweden)

    Xiao Zhijun

    2016-01-01

    Full Text Available Based on the filed data of Fuzhou test road, load response regulation of nonlinear pavement structure was analyzed in this paper; Mechanics software was adopted to analyze linear elastic and nonlinear of the pavement structure, analyzed results and road filed data were compared, and determine the correlation between them and the field data.

  6. Pervious Pavement System Evaluation-Paper

    Science.gov (United States)

    The use of a pervious pavement can be effective as a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete paver systems as a type of porous pavement. Although the pavers are impermeable, the spaces between the pave...

  7. Numerical Simulation of Tire-Pavement Interaction

    NARCIS (Netherlands)

    Srirangam, S.K.

    2015-01-01

    Good skid resistance of a pavement surface is essential for road safety. Loss of skid resistance can lead to property damage and loss of lives. Ever increasing need of driver safety poses challenges to the highway authorities to evaluate pavement conditions even more precisely under different

  8. Crackscope : automatic pavement cracking inspection system.

    Science.gov (United States)

    2008-08-01

    The CrackScope system is an automated pavement crack rating system consisting of a : digital line scan camera, laser-line illuminator, and proprietary crack detection and classification : software. CrackScope is able to perform real-time pavement ins...

  9. Modelling Flexible Pavement Response and Performance

    DEFF Research Database (Denmark)

    Ullidtz, Per

    This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods.......This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods....

  10. Field cracking performance of airfield rigid pavements

    Directory of Open Access Journals (Sweden)

    Yusuf Mehta

    2017-08-01

    Full Text Available This paper discusses cracking in airport pavements as studied in Construction Cycle 6 of testing carried out at the National Airport Pavement Testing Facility by the Federal Aviation Administration. Pavements of three different flexural strengths as well as two different subgrades, a soft bituminous layer and a more rigid layer known as econocrete, were tested. In addition to this, cracking near two types of isolated transition joints, a reinforced edge joint and a thickened edge joint, was considered. The pavement sections were tested using a moving load simulating that of an aircraft. It has been determined that the degree of cracking was reduced as the flexural strength of the pavement was increased and that fewer cracks formed over the econocrete base than over the bituminous base. In addition, the thickened edge transition joint was more effective in preventing cracking at the edges compared to the reinforced edge joint.

  11. Automatic Road Pavement Assessment with Image Processing: Review and Comparison

    Directory of Open Access Journals (Sweden)

    Sylvie Chambon

    2011-01-01

    Full Text Available In the field of noninvasive sensing techniques for civil infrastructures monitoring, this paper addresses the problem of crack detection, in the surface of the French national roads, by automatic analysis of optical images. The first contribution is a state of the art of the image-processing tools applied to civil engineering. The second contribution is about fine-defect detection in pavement surface. The approach is based on a multi-scale extraction and a Markovian segmentation. Third, an evaluation and comparison protocol which has been designed for evaluating this difficult task—the road pavement crack detection—is introduced. Finally, the proposed method is validated, analysed, and compared to a detection approach based on morphological tools.

  12. Application of infrared camera to bituminous concrete pavements: measuring vehicle

    Science.gov (United States)

    Janků, Michal; Stryk, Josef

    2017-09-01

    Infrared thermography (IR) has been used for decades in certain fields. However, the technological level of advancement of measuring devices has not been sufficient for some applications. Over the recent years, good quality thermal cameras with high resolution and very high thermal sensitivity have started to appear on the market. The development in the field of measuring technologies allowed the use of infrared thermography in new fields and for larger number of users. This article describes the research in progress in Transport Research Centre with a focus on the use of infrared thermography for diagnostics of bituminous road pavements. A measuring vehicle, equipped with a thermal camera, digital camera and GPS sensor, was designed for the diagnostics of pavements. New, highly sensitive, thermal cameras allow to measure very small temperature differences from the moving vehicle. This study shows the potential of a high-speed inspection without lane closures while using IR thermography.

  13. Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements

    Directory of Open Access Journals (Sweden)

    Tarefder R.

    2013-01-01

    Full Text Available This study evaluates airfield pavements’ functional- and structural-condition to determine the most economical maintenance method. As a part of the analysis, Pavement Condition Index (PCI for several runways, taxiways, and aprons has been determined by MicroPAVER. Structural evaluation of airport pavements has been performed by Falling Weight Deflectometer (FWD test. Evaluation of Layer Moduli and Overlay Design (ELMOD also determines the required overlay thickness based on the E-values, i.e. FWD data analysis. Damage analysis determines the time of repeated overlay application. In addition, functional parameters have been included to determine the time of functional maintenance. Maintenance and rehabilitation alternatives have been selected to develop different program strategies. Life Cycle Cost Analysis (LCCA has been performed to determine the maintenance cost. Structural condition based maintenance cost is compared to functional condition based maintenance cost. Comparison shows that structural condition based approach yields cheaper maintenance strategies than functional condition based maintenance approach.

  14. Comparisons of Faulting-Based Pavement Performance Prediction Models

    Directory of Open Access Journals (Sweden)

    Weina Wang

    2017-01-01

    Full Text Available Faulting prediction is the core of concrete pavement maintenance and design. Highway agencies are always faced with the problem of lower accuracy for the prediction which causes costly maintenance. Although many researchers have developed some performance prediction models, the accuracy of prediction has remained a challenge. This paper reviews performance prediction models and JPCP faulting models that have been used in past research. Then three models including multivariate nonlinear regression (MNLR model, artificial neural network (ANN model, and Markov Chain (MC model are tested and compared using a set of actual pavement survey data taken on interstate highway with varying design features, traffic, and climate data. It is found that MNLR model needs further recalibration, while the ANN model needs more data for training the network. MC model seems a good tool for pavement performance prediction when the data is limited, but it is based on visual inspections and not explicitly related to quantitative physical parameters. This paper then suggests that the further direction for developing the performance prediction model is incorporating the advantages and disadvantages of different models to obtain better accuracy.

  15. Theoretical Relationships Between Moduli for Soil Layers Beneath Concrete Pavements.

    Science.gov (United States)

    method of analysis used for rigid pavements and the elastic layer method of analysis used for both rigid and flexible pavements. Twenty-three pavement sections were selected to illustrate the usage of these relationships. These sections represent the widest possible variation of rigid pavement types for which sufficient materials data was available. For the sections studied and within the context of linear analysis, these relationships demonstrate that the peak pavement stress can usually be computed by either method

  16. Performance-Based Evaluation of Joint Sealants for Concrete Pavements

    OpenAIRE

    Khuri, Ramzi Emile

    1998-01-01

    Pavement concrete joints are the weakest locations in concrete pavement systems. They are man-made cracks to accommodate concrete slab expansion and contraction due to temperature fluctuations. Sealant is usually used in pavement joints to prevent roadway debris, deicing chemicals, and moisture from entering the joint. When sealant fails, the pavement deteriorates rapidly; and when joint sealant performs adequately, the pavement preserves its intended performance. In the field, joint seala...

  17. A study on LMFBR steam generator design without tube failure propagation in water leak events

    International Nuclear Information System (INIS)

    Futagami, Satoshi; Hayafune, Hiroki; Fujimura, Ken; Sato, Mitsuru

    2009-01-01

    The major target performance of the SG for commercialized FBR is not only economic performance but also property protection performance. The candidate SG design will be selected at the end of JFY 2010. The straight double wall tube SG is one of the SG candidates for commercialized FBR, and other SG concepts were studied in this paper. In proposing an alternative SG, alternative technological measures with a double wall tube were investigated and included reinforcing the tube against wastage and quick detection of initial tube leaks. Alternative SG concept candidates for preventing tube failure propagation and mitigation of water leak accidents were proposed through a combination of technological measures. The candidates were then comparatively evaluated from the point of view of property protection performance, total weight, technological issues, and so on. A coated wall tube SG and protective wall tube SG were decided on as the alternative SGs because of superior property protection performance and with the technological issues. At the end of JFY 2010, the straight double wall tube SG will be decided upon as the result of R and D activities, and alternative SGs evaluated in feasibility studies. A plan for studying feasibility with the technological issues of the alternative SG was proposed. (author)

  18. On the failure modes of alternative containment designs following postulated core meltdown

    International Nuclear Information System (INIS)

    Chan, C.K.; Knee, H.E.; Okrent, D.

    1977-01-01

    The containment response to a postulated core meltdown accident in a PWR ice condenser containment, a BWR Mark III containment and a BWR non-inerted Mark I containment has been examined to see if the WASH-1400 containment failure mode judgement for the Surry large, dry containment and the Peach Bottom Mark I inerted-containment are likely to be appropriate for these alternative containment plant designs. For the PWR, the representative accident chosen for the analysis is a large cold leg break accompanied by a loss of all electric power while the BWR respresentative event chosen is a recirculation line break without adequate core cooling function. Two containment event paths are studied for each of these two cases, depending on whether or not containment vapor suppression function is assumed to be available. Both the core and the containment pressure and temperature response to the accident events are computed for the four time intervals which characterize (a) blowdown of the pipe break, (b) core melt, (c) vessel melt-through, and (d) containment foundation penetration. The calculations are based on a best esimate of the most probable sequence, but certain phenomena and events were followed down multiple tracks. It appears that the non-inerted Mark I containment is not so vulnerable to overpressurization from hydrogen burning as the Mark III; however, acceptable temperatures may be exceeded. (Auth.)

  19. Catastrophic Failure and Fault-Tolerant Design of IGBT Power Electronic Converters - An Overview

    DEFF Research Database (Denmark)

    Wu, Rui; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    -event overstress. The wear out failure under field operation could be mitigated by scheduled maintenances based on lifetime prediction and condition monitoring. However, the catastrophic failure is difficult to be predicted and thus may lead to serious consequence of power electronic converters. To obtain a better...

  20. Sensitivity quantification of airport concrete pavement stress responses associated with top-down and bottom-up cracking

    Directory of Open Access Journals (Sweden)

    Adel Rezaei-Tarahomi

    2017-09-01

    Full Text Available The Federal Aviation Administration’s (FAA’s rigid pavement design standard employs the NIKE3D-FAA software to compute critical pavement responses of concrete airport pavement structures. NIKE3D-FAA is a modification of the original NIKE3D three-dimensional finite element analysis program developed by the Lawrence Livermore National Laboratory (LLNL of the U.S. Department of Energy, and is currently used in the FAA’s FAARFIELD program. This study evaluated the sensitivity of NIKE3D-FAA rigid pavement responses with respect to top-down and bottom-up cracking. The analysis was conducted by positioning a Boeing 777-300ER (B777-300ERaircraft at different locations (interior, corner, and edge of slab as baseline while varying other NIKE3D-FAA inputs, including rigid pavement geometric features, mechanical properties of paving and foundation materials, equivalent temperature gradient and thermal coefficient of Portland Cement Concrete (PCC layers. Several sensitivity charts were developed by examining the sensitivity of critical pavement responses to each input variation. Sensitivity evaluations were performed using a normalized sensitivity index (NSI as the quantitative metric. Using such sensitivity evaluation, the most significant NIKE3D-FAA input parameters for generating an effective synthetic database that will lower computational cost for future modeling developments were identified. Keywords: Sensitivity analysis, Airfield concrete pavement, Finite element analysis, Top down cracking

  1. Investigation clogging dynamic of permeable pavement systems using embedded sensors

    Science.gov (United States)

    Razzaghmanesh, Mostafa; Borst, Michael

    2018-02-01

    Permeable pavement is a stormwater control measure commonly selected in both new and retrofit applications. However, there is limited information about the clogging mechanism of these systems that effects the infiltration. A permeable pavement site located at the Seitz Elementary School, on Fort Riley, Kansas was selected for this study. An 80-space parking lot was built behind the school as part of an EPA collaboration with the U.S. Army. The parking lot design includes a permeable interlocking concrete pavement section along the downgradient edge. This study monitored the clogging progress of the pavement section using twelve water content reflectometers and three buried tipping bucket rain gauges. This clogging dynamic investigation was divided into three stages namely pre-clogged, transitional, and clogged. Recorded initial relative water content of all three stages were significantly and negatively correlated to antecedent dry weather periods with stronger correlations during clogged conditions. The peak relative water content correlation with peak rainfall 10-min intensity was significant for the water content reflectometers located on the western edge away from the eastern edge; this correlation was strongest during transition stage. Once clogged, rainfall measurements no longer correlated with the buried tipping bucket rain gauges. Both water content reflectometers and buried tipping bucket rain gauges showed the progress of surface clogging. For every 6 mm of rain, clogging advanced 1 mm across the surface. The results generally support the hypothesis that the clogging progresses from the upgradient to the downgradient edge. The magnitude of the contributing drainage area and rainfall characteristics are effective factors on rate and progression of clogging.

  2. Network level pavement evaluation with 1 mm 3D survey system

    Directory of Open Access Journals (Sweden)

    Kelvin C.P. Wang

    2015-12-01

    Full Text Available The latest iteration of PaveVision3D Ultra can obtain true 1 mm resolution 3D data at full-lane coverage in all 3 directions at highway speed up to 60 mph. This paper introduces the PaveVision3D Ultra technology for rapid network level pavement survey on approximately 1280 center miles of Oklahoma interstate highways. With sophisticated automated distress analyzer (ADA software interface, the collected 1 mm 3D data provide Oklahoma Department of Transportation (ODOT with comprehensive solutions for automated evaluation of pavement surface including longitudinal profile for roughness, transverse profile for rutting, predicted hydroplaning speed for safety analysis, and cracking and various surface defects for distresses. The pruned exact linear time (PELT method, an optimal partitioning algorithm, is implemented to identify change points and dynamically determine homogeneous segments so as to assist ODOT effectively using the available 1 mm 3D pavement surface condition data for decision-making. The application of 1 mm 3D laser imaging technology for network survey is unprecedented. This innovative technology allows highway agencies to access its options in using the 1 mm 3D system for its design and management purposes, particularly to meet the data needs for pavement management system (PMS, pavement ME design and highway performance monitoring system (HPMS.

  3. Assessment of highway pavements using GPR

    Science.gov (United States)

    Plati, Christina; Loizos, Andreas

    2015-04-01

    Highway infrastructure is a prerequisite for a functioning economy and social life. Highways, often prone to congestion and disruption, are one of the aspects of a modern transport network that require maximum efficiency if an integrated transport network, and sustainable mobility, is to be achieved. Assessing the condition of highway structures, to plan subsequent maintenance, is essential to allow the long-term functioning of a road network. Optimizing the methods used for such assessment will lead to better information being obtained about the road and underlying ground conditions. The condition of highway structures will be affected by a number of factors, including the properties of the highway pavement, the supporting sub-base and the subgrade (natural ground), and the ability to obtain good information about the entire road structure, from pavement to subgrade, allows appropriate maintenance programs to be planned. The maintenance of highway pavements causes considerable cost and in many cases obstruction to traffic flow. In this situation, methods that provide information on the present condition of pavement structure non-destructively and economically are of great interest. It has been shown that Ground-Penetrating-Radar (GPR), which is a Non Destructive Technique (NDT), can deliver information that is useful for the planning of pavement maintenance activities. More specifically GPR is used by pavement engineers in order to determine physical properties and characteristics of the pavement structure, information that is valuable for the assessment of pavement condition. This work gives an overview on the practical application of GPR using examples from highway asphalt pavements monitoring. The presented individual applications of GPR pavement diagnostics concern structure homogeneity, thickness of pavement layers, dielectric properties of asphalt materials etc. It is worthwhile mentioning that a number of applications are standard procedures, either

  4. Heart Failure Therapeutics on the Basis of a Biased Ligand of the Angiotensin-2 Type 1 Receptor Rationale and Design of the BLAST-AHF Study (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure)

    NARCIS (Netherlands)

    Felker, G. Michael; Butler, Javed; Collins, Sean P.; Cotter, Gad; Davison, Beth A.; Ezekowitz, Justin A.; Filippatos, Gerasimos; Levy, Phillip D.; Metra, Marco; Ponikowski, Piotr; Soergel, David G.; Teerlink, John R.; Violin, Jonathan D.; Voors, Adriaan A.; Pang, Peter S.

    The BLAST-AHF (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure) study is designed to test the efficacy and safety of TRV027, a novel biased ligand of the angiotensin-2 type 1 receptor, in patients with acute heart failure (AHF). AHF remains a major public health problem, and

  5. Design and performance of a multisensor heart failure monitoring algorithm: results from the multisensor monitoring in congestive heart failure (MUSIC) study.

    Science.gov (United States)

    Anand, Inder S; Tang, W H Wilson; Greenberg, Barry H; Chakravarthy, Niranjan; Libbus, Imad; Katra, Rodolphe P

    2012-04-01

    Remote monitoring of heart failure (HF) patients may help in the early detection of acute decompensation before the onset of symptoms, providing the opportunity for early intervention to reduce HF-related hospitalizations, improve outcomes, and lower costs. MUSIC is a multicenter nonrandomized study designed to develop and validate an algorithm for prediction of impending acute HF decompensation with the use of physiologic signals obtained from an external device adhered to the chest. A total of 543 HF patients (206 development, 337 validation) with ejection fraction ≤40% and a recent HF admission were enrolled. Patients were remotely monitored for 90 days using a multisensor device. Accounting for device failure and patient withdrawal, 314 patients (114 development, 200 validation) were included in the analysis. Development patient data were used to develop a multiparameter HF detection algorithm. Algorithm performance in the development cohort had 65% sensitivity, 90% specificity, and a false positive rate of 0.7 per patient-year for detection of HF events. In the validation cohort, algorithm performance met the prespecified end points with 63% sensitivity, 92% specificity, and a false positive rate of 0.9 per patient-year. The overall rate of significant adverse skin response was 0.4%. Using an external multisensor monitoring system, an HF decompensation prediction algorithm was developed that met the prespecified performance end point. Further studies are required to determine whether the use of this system will improve patient outcomes. Published by Elsevier Inc.

  6. Factors Influencing Stormwater Mitigation in Permeable Pavement

    Directory of Open Access Journals (Sweden)

    Chun Yan Liu

    2017-12-01

    Full Text Available Permeable pavement (PP is used worldwide to mitigate surface runoff in urban areas. Various studies have examined the factors governing the hydrologic performance of PP. However, relatively little is known about the relative importance of these governing factors and the long-term hydrologic performance of PP. This study applied numerical models—calibrated and validated using existing experimental results—to simulate hundreds of event-based and two long-term rainfall scenarios for two designs of PP. Based on the event-based simulation results, rainfall intensity, rainfall volume, thickness of the storage layer and the hydraulic conductivity of the subgrade were identified as the most influential factors in PP runoff reduction. Over the long term, PP performed significantly better in a relatively drier climate (e.g., New York, reducing nearly 90% of runoff volume compared to 70% in a relatively wetter climate (e.g., Hong Kong. The two designs of PP examined performed differently, and the difference was more apparent in the relatively wetter climate. This study generated insights that will help the design and implementation of PP to mitigate stormwater worldwide.

  7. Nondestructive Evaluation of Airport Pavements. Volume I. Program References,

    Science.gov (United States)

    1979-09-01

    Bandwidth norm/visual or lights/ILS ground navigation 2. Radius Radius of tire contact area 3. X Transverse wheel spacing 4. Facility RW, TW and HP 5. Y...HLBT POZBT SFST IWFAT RSWLB LBBM CLHR SLEHR 1 .0 . 0235 .0500 .0051 .0 .0 .0 .0 .0 .0 .0112 .0217 2 .0007 .0 .0200 .0 .0020 .0067 .0374 .0 .0 .0 .0027...SESSION 4 PAVEMENT DESIGN AND COST-BENEFIT STUDY Design Thickness and Composition 1. Establish Default Input Files Facility Type RW, TW, HP Bandwidth

  8. Developing guidelines for repairing severe edge failures : technical report.

    Science.gov (United States)

    2014-04-01

    This report presents various edge failures, the methods used by districts to repair them, and the results of the : repair. While there was no clear consensus on the best treatment of in-situ material for pavements with edge : failures, the districts ...

  9. User's guide : pavement marking management system database.

    Science.gov (United States)

    2011-12-01

    Pavement markings play a critical role in maintaining a safe and efficient driving environment for road users, especially during nighttime conditions. The Texas Department of Transportation (TxDOT) spends millions of dollars each year for installatio...

  10. Permeable Pavement Research - Edison, New Jersey

    Science.gov (United States)

    This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

  11. Class C fly ash in pavements.

    Science.gov (United States)

    2010-07-01

    Portland cement is the most dominant material used in concrete pavements in the state of Nebraska. In order to improve performance, reduce cost, and advance sustainability, a percentage of the Portland cement is replaced with a recycled material know...

  12. Performance of I-57 recycled concrete pavements.

    Science.gov (United States)

    2009-01-01

    In 1986-1987 the Illinois Department of Transportation (IDOT) constructed a demonstration project on I-57 near Effingham, Illinois to evaluate the viability : of recycling an existing jointed reinforced concrete pavement for use as its primary aggreg...

  13. Pervious Pavement System Evaluation- Abstract 1

    Science.gov (United States)

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  14. Long term monitoring of moisture under pavements.

    Science.gov (United States)

    2010-01-01

    Monitoring of the environmental instrumentation installed under select pavement sections constructed : by the Ohio Department of Transportation (ODOT) in 1995 on US 23 in Delaware County, Ohio was : continued. The measurements made consisted of soil ...

  15. Concrete pavement construction basics : tech notes.

    Science.gov (United States)

    2006-08-01

    This tech note has been produced for developers, consultants, and engineers planning concrete pavement construction projects, superintendents and supervisors who want a basic training aid and reference, and crew members new to the concrete paving ind...

  16. Noise measurements of highway pavements in Texas.

    Science.gov (United States)

    2009-10-01

    This report presents the results of noise testing performed on Texas pavements between May of 2006 and the : summer of 2008. Two field test methodologies were used: roadside noise measurement with SPL meters and onvehicle : sound intensity measuremen...

  17. Improving safety in pavement field testing.

    Science.gov (United States)

    2017-09-15

    The Florida Department of Transportation (FDOT) collects pavement condition and performance data each year, using both site-specific equipment that requires temporary traffic control (TTC) operations (either moving or closed operations) and full-size...

  18. Reformulated pavement remaining service life framework.

    Science.gov (United States)

    2013-11-01

    "Many important decisions are necessary in order to effectively provide and manage a pavement network. At the heart : of this process is the prediction of needed future construction events. One approach to providing a single numeric on : the conditio...

  19. Optimization of safety on pavement preservation projects.

    Science.gov (United States)

    2011-01-01

    To achieve a goal of reducing highway crash fatalities by 4% each year to improve roadway safety, the Georgia Department of Transportation (GDOT) is actively seeking opportunities to incorporate safety improvements into its current pavement preservat...

  20. On-road Bicycle Pavement Markings

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — A mile by mile breakdown of the on-street bicycle pavement markings installed within the City of Pittsburgh. These include bike lanes, shared lane markings...

  1. Life cycle assessment of asphalt pavement maintenance.

    Science.gov (United States)

    2014-01-01

    This study aims at developing a life cycle assessment (LCA) model to quantify the impact of pavement preservation on energy consumption and greenhouse gas (GHG) emissions. The construction stage contains material, manufacture, transportation and plac...

  2. Performance evaluation of precast prestressed concrete pavement.

    Science.gov (United States)

    2007-11-01

    This report describes in detail an experimental investigation of an innovative precast prestressed concrete pavement (PPCP) system used to rehabilitate a 1,000 ft. section of interstate highway located on the northbound lanes of I-57 near Charleston,...

  3. Effect of microthread presence and restoration design (screw versus cemented) in dental implant reliability and failure modes.

    Science.gov (United States)

    Almeida, Erika O; Freitas Júnior, Amilcar C; Bonfante, Estevam A; Rocha, Eduardo Passos; Silva, Nelson R F A; Coelho, Paulo G

    2013-02-01

    This study evaluated the reliability and failure modes of implants with a microthreaded or smooth design at the crestal region, restored with screwed or cemented crowns. The postulated null hypothesis was that the presence of microthreads in the implant cervical region would not result in different reliability and strength to failure than smooth design, regardless of fixation method, when subjected to step-stress accelerated life-testing (SSALT) in water. Eighty four dental implants (3.3 × 10 mm) were divided into four groups (n = 21) according to implant macrogeometric design at the crestal region and crown fixation method: Microthreads Screwed (MS); Smooth Screwed (SS); Microthreads Cemented (MC), and Smooth Cemented (SC). The abutments were torqued to the implants and standardized maxillary central incisor metallic crowns were cemented (MC, SC) or screwed (MS, SS) and subjected to SSALT in water. The probability of failure versus cycles (90% two-sided confidence intervals) was calculated and plotted using a power law relationship for damage accumulation. Reliability for a mission of 50,000 cycles at 150 N (90% 2-sided confidence intervals) was calculated. Differences between final failure loads during fatigue for each group were assessed by Kruskal-Wallis along with Benferroni's post hoc tests. Polarized-light and scanning electron microscopes were used for failure analyses. The Beta (β) value (confidence interval range) derived from use level probability Weibull calculation of 1.30 (0.76-2.22), 1.17 (0.70-1.96), 1.12 (0.71-1.76), and 0.52 (0.30-0.89) for groups MC, SC, MS, and SS respectively, indicated that fatigue was an accelerating factor for all groups, except for SS. The calculated reliability was higher for SC (99%) compared to MC (87%). No difference was observed between screwed restorations (MS - 29%, SS - 43%). Failure involved abutment screw fracture for all groups. The cemented groups (MC, SC) presented more abutment and implant fractures

  4. Influence of specimen design on the deformation and failure of zircaloy cladding

    International Nuclear Information System (INIS)

    Bates, D.W.; Koss, D.A.; Motta, A.T.; Majumdar, S.

    2000-01-01

    Experimental as well as computational analyses have been used to examine the deformation and failure behavior of ring-stretch specimens of Zircaloy-4 cladding tubes. The results show that, at least for plastically anisotropic unirradiated cladding, specimens with a small gauge length l to width w ratio (l/w ∼ 1) exhibit pronounced non-uniform deformation along their length. As a result, specimen necking occurs upon yielding when the specimen is fully plastic. Finite element analysis indicates a minimum l/w of 4 before a significant fraction of the gauge length deforms homogeneously. A brief examination of the contrasting deformation and failure behavior between uniaxial and plane-strain ring tension tests further supports the use of the latter geometry for determining cladding failure ductility data that are relevant to certain reactivity-initiated accident conditions

  5. Design and Rationale of the Cognitive Intervention to Improve Memory in Heart Failure Patients Study.

    Science.gov (United States)

    Pressler, Susan J; Giordani, Bruno; Titler, Marita; Gradus-Pizlo, Irmina; Smith, Dean; Dorsey, Susan G; Gao, Sujuan; Jung, Miyeon

    2018-03-29

    Memory loss is an independent predictor of mortality among heart failure patients. Twenty-three percent to 50% of heart failure patients have comorbid memory loss, but few interventions are available to treat the memory loss. The aims of this 3-arm randomized controlled trial were to (1) evaluate efficacy of computerized cognitive training intervention using BrainHQ to improve primary outcomes of memory and serum brain-derived neurotrophic factor levels and secondary outcomes of working memory, instrumental activities of daily living, and health-related quality of life among heart failure patients; (2) evaluate incremental cost-effectiveness of BrainHQ; and (3) examine depressive symptoms and genomic moderators of BrainHQ effect. A sample of 264 heart failure patients within 4 equal-sized blocks (normal/low baseline cognitive function and gender) will be randomly assigned to (1) BrainHQ, (2) active control computer-based crossword puzzles, and (3) usual care control groups. BrainHQ is an 8-week, 40-hour program individualized to each patient's performance. Data collection will be completed at baseline and at 10 weeks and 4 and 8 months. Descriptive statistics, mixed model analyses, and cost-utility analysis using intent-to-treat approach will be computed. This research will provide new knowledge about the efficacy of BrainHQ to improve memory and increase serum brain-derived neurotrophic factor levels in heart failure. If efficacious, the intervention will provide a new therapeutic approach that is easy to disseminate to treat a serious comorbid condition of heart failure.

  6. Development of Pavement Condition Index Model Using PAVER 6.5.7 for Flexible Pavement Urban Roads in Kerbala City

    OpenAIRE

    Hussein Ali Ewadh; Raid Rahman Almuhanna; Saja Jasim Alasadi

    2017-01-01

    The pavement condition index (PCI) is an important factor indicating pavement condition of roads. The pavement is one of the basic parts of the road infrastructure. Accordingly the aim of this paper is to develop a pavement condition index model using PAVER 6.5.7 for a flexible pavement urban roads in the Kerbala city center. The development model is depending on the PCI value of 109 sample sections having 57.8 km length, Data collected for pavement distress (type, dimension, and severity) w...

  7. Early Phase Contingency Trajectory Design for the Failure of the First Lunar Orbit Insertion Maneuver: Direct Recovery Options

    Science.gov (United States)

    Song, Young-Joo; Bae, Jonghee; Kim, Young-Rok; Kim, Bang-Yeop

    2017-12-01

    To ensure the successful launch of the Korea pathfinder lunar orbiter (KPLO) mission, the Korea Aerospace Research Institute (KARI) is now performing extensive trajectory design and analysis studies. From the trajectory design perspective, it is crucial to prepare contingency trajectory options for the failure of the first lunar brake or the failure of the first lunar orbit insertion (LOI) maneuver. As part of the early phase trajectory design and analysis activities, the required time of flight (TOF) and associated delta-V magnitudes for each recovery maneuver (RM) to recover the KPLO mission trajectory are analyzed. There are two typical trajectory recovery options, direct recovery and low energy recovery. The current work is focused on the direct recovery option. Results indicate that a quicker execution of the first RM after the failure of the first LOI plays a significant role in saving the magnitudes of the RMs. Under the conditions of the extremely tight delta-V budget that is currently allocated for the KPLO mission, it is found that the recovery of the KPLO without altering the originally planned mission orbit (a 100 km circular orbit) cannot be achieved via direct recovery options. However, feasible recovery options are suggested within the boundaries of the currently planned delta-V budget. By changing the shape and orientation of the recovered final mission orbit, it is expected that the KPLO mission may partially pursue its scientific mission after successful recovery, though it will be limited.

  8. Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.

    Science.gov (United States)

    Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results.

  9. Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions

    Directory of Open Access Journals (Sweden)

    Zhang Junwei

    2013-01-01

    Full Text Available The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results.

  10. Design of Airport Pavements for Expansive Soils.

    Science.gov (United States)

    1981-01-01

    34 .’. . , . Vol. 57:437-444. Nunez, E., and Carrillo, A., (1977) " Suelos Especiales: Colapsibles, Expansivo , Preconsolidados por Desecacion...1975) "Las Arcillas Expansivas: Su Estudio y Trataniento," Laboratorio del Transporte y Mechanica del Suelo , i.,’. ". pp. 3-30. Russam, Kenneth

  11. Self-healing polymeric composite material design, failure analysis and future outlook: A review

    CSIR Research Space (South Africa)

    Mphahlele, Keletso

    2017-10-01

    Full Text Available reduces the lifespan and brings about a catastrophic failure of the materials. Novel scientific research on polymeric self-healing is emphasised in a number of publications, which consist of contributions from many of the prominent researchers in this area...

  12. 3-D cohesive finite element model for application in structural analysis of heavy duty composite pavements

    DEFF Research Database (Denmark)

    Skar, Asmus; Poulsen, Peter Noe

    2015-01-01

    The problem of stiffness degradation in composite pavement systems from localised fracture damage in the quasibrittle cement bound granular mixture are today taken into account only by empirical formulas. These formulas deals with a limited number of materials in a restricted range of design...... options and would yield unrealistic results in ultimate loading conditions. Cohesive modelling is one of the primary methods to handle localised damage in quasi-brittle materials, e.g., concrete, describing the potential crack in a discrete manner. To increase the versatility of existing methods...... this paper presents a numerical analysis of the fracture behaviour of cement bound granular mixtures in composite concrete block pavement systems applying a cohesive model. The functionality of the proposed model is compared to experimental investigations of beam bending tests. The pavement is modelled...

  13. Design of the Multi-Sensor Monitoring in Congestive Heart Failure (MUSIC) study: prospective trial to assess the utility of continuous wireless physiologic monitoring in heart failure.

    Science.gov (United States)

    Anand, Inder S; Greenberg, Barry H; Fogoros, Richard N; Libbus, Imad; Katra, Rodolphe P

    2011-01-01

    Remote monitoring of heart failure (HF) patients may help in the early detection of acute HF decompensation before the onset of symptoms. Appropriate early intervention in these patients may reduce HF-related hospitalizations and costs. The MUSIC (Multi-Sensor Monitoring in Congestive Heart Failure) study comprises 2 multicenter nonrandomized phases (MUSIC-Development and MUSIC-Validation) designed to develop and validate an algorithm for the prediction of acute HF decompensation using multiple physiologic signals obtained from an external, adherent, multisensor system capable of intermittent transmission of physiologic signals. Data obtained from MUSIC-Development will be used to develop the algorithm to predict HF decompensation. The algorithm will be validated in MUSIC-Validation with the objectives of ≥ 60% sensitivity for correctly predicting an acute HF event, a false-positive patient status signal rate of ≤ 1.0 per patient-year, and a safety endpoint of ≤ 5% of patients experiencing significant adverse skin conditions related to the prolonged wearing of the adherent device. A total of 542 patients in New York Heart Association functional class III-IV HF, with ejection fraction ≤ 40% and a recent HF admission, are enrolled in MUSIC-Development (n = 180) and MUSIC-Validation (n = 362). All patients are remotely monitored for 90 days using the Corventis multisensor system that transmits bioimpedance, electrocardiogram, and accelerometer data. The MUSIC study has completed patient enrollment and follow-up in both phases. Once algorithm development is complete from the MUSIC-Development phase, the sequestered data set from the MUSIC-Validation phase will be used for algorithm validation. Published by Elsevier Inc.

  14. Demonstration of using quieter pavement in Death Valley National Park

    Science.gov (United States)

    2013-06-01

    Death Valley National Park provided an environment that allowed a demonstration of : quieter pavement use. Sound measurements near the tire-pavement interface, near the : road, and in areas of frequent human use were conducted and analyses performed ...

  15. Continuous real time measurement of pavement quality during construction.

    Science.gov (United States)

    2010-12-01

    Intelligent Compaction has been investigated as a means of improving the quality of asphalt pavements during their : construction. The long term performance of an asphalt pavement is directly related to its load bearing capability and : is determined...

  16. Laboratory fatigue evaluation of continuously fiber-reinforced concrete pavement.

    Science.gov (United States)

    2013-09-01

    Portland cement concrete (PCC) is the worlds most versatile construction material. PCC has : been in use in the United States for over 100 years. PCC pavement is generally constructed as : either continually reinforced concrete pavement (CRCP) or ...

  17. Evaluation of recycled concrete as aggregate in new concrete pavements.

    Science.gov (United States)

    2014-04-01

    This study evaluated the use of recycled concrete as coarse aggregate in new concrete pavements. : Recycled concrete aggregate (RCA) produced from demolished pavements in three geographically dispersed locations in Washington state were used to perfo...

  18. Mobile geographic information system solution for pavement condition surveys [summary].

    Science.gov (United States)

    2012-01-01

    The State Materials Office (SMO) of the Florida : Department of Transportation (FDOT) performs : annual Pavement Condition Surveys (PCS) of : the Departments extensive pavement network. : This work is performed by single-person crews in : inertial...

  19. Effect of friction on rolling tire-pavement interaction

    Science.gov (United States)

    2010-11-01

    In this research, a three-dimensional (3-D) tire-pavement interaction model is developed using FEM to analyze the tire-pavement contact stress distributions at various rolling conditions (free rolling, braking/accelerating, and cornering). In additio...

  20. Advanced Automated Detection Analysis and Classification of Cracks in Pavement

    OpenAIRE

    Scott, Dennis

    2014-01-01

    Functional Session 5: Pavement Management Moderated by Akyiaa Hosten This presentation was held at the Pavement Evaluation 2014 Conference, which took place from September 15-18, 2014 in Blacksburg, Virginia. Presentation only

  1. Investigation clogging dynamic of permeable pavement systems using embedded sensors

    Science.gov (United States)

    Permeable pavement is a stormwater control measure commonly selected in both new and retrofit applications. However, there is limited information about the clogging mechanism of these systems that effects the infiltration. A permeable pavement site located at the Seitz Elementary...

  2. Performance and cost effectiveness of permeable friction course (PFC) pavements.

    Science.gov (United States)

    2013-02-01

    In this project, the research team evaluated the performance of Permeable Friction Courses (PFC) over time and compared it against other types of wearing surface pavement layers. Several pavement sections including Asphalt Rubber (AR) PFCs, Performan...

  3. Software offers transparent, straightforward assessment of pavement additives : research spotlight.

    Science.gov (United States)

    2015-04-01

    Adding new materials to pavement layers is a proven technique to : improve performance. Many types of additivesfrom engineered : polymers and acids to recycled pavement, crumb rubber, shingles : and glasshave been used to help construct better ...

  4. Evaluation of Procedures for Backcalculation of Airfield Pavement Moduli

    Science.gov (United States)

    2015-08-01

    surface and the base pavement is positively in good condition Cb = 0.8 if only reflective cracks or only joint reflective cracks are present on...backcalculation routine with the real pavement scenario.  Testing in proximity of cracks or joints results in measured deflection basins that... pavement (JPCP) 1 Plant mix (emulsified asphalt) material, cold-laid 20 Jointed reinforced concrete pavement (JRCP) 1 Cracked and seated PCC

  5. Pavement Condition Survey in Kagawa Prefecture using ROMDAS

    OpenAIRE

    Mohammad, Mamunur Rashid; 角川, 浩二

    2006-01-01

    Highway is one of the most important areas among the various facilities of infrastructure. Therefore, most of the organizations related to the infrastructure management system pay higher attention to the pavement which is the most important facility of highway management. An effective pavement management system (PMS) helps to carry out all the preservation and necessary maintenance operations of the pavement. In order to implement a pavement management system, data collection that indicates e...

  6. A fuzzy logic approach for pavement section classification

    OpenAIRE

    Mahmood, M; Rahman, M; Nolle, L; Mathavan, S

    2013-01-01

    Section classification is one of the primary challenges in any successful pavement management system. Sections are normally classified based on their pavement condition index in order to categorise as "good", "moderate" and "poor". Conventionally, this has been done by comparing various pavement distress data against threshold values. However, borderline values between two categories have significant influence on the subsequent pavement maintenance and rehabilitation decision. This study is t...

  7. AutoPAVER: A software package for automated pavement evaluation

    Science.gov (United States)

    Ginsberg, Mark D.; Shahin, M. Y.; Walther, Jeanette A.

    1990-07-01

    This research developed a method that improves data collection and reduces data entry times for Pavement Condition Index (PCI) surveys for use with PAVER, a pavement maintenance management system. The method, AutoPAVER, is a microcomputer software package used to analyze pictures of pavement surfaces and to forward the resulting analysis to PAVER. The user works interactively with the system to identify and classify pavement distresses. Distress measurement and data entry are done on the computer.

  8. Pavement Condition Survey in Kagawa Prefecture using ROMDAS

    OpenAIRE

    Mohammad Mamunur Rashid; 角川, 浩二

    2005-01-01

    Highway is one of the most important areas among the various facilities of infrastructure. Therefore, most of the organizations related to the infrastructure management system pay higher attention to the pavement which is the most important facility of highway management. An effective pavement management system (PMS) helps to carry out all the preservation and necessary maintenance operations of the pavement. In order to implement a pavement management system, data collection that indicates e...

  9. Investigation of the Asphalt Pavement Analyzer (APA) testing program in Nebraska.

    Science.gov (United States)

    2008-03-01

    The asphalt pavement analyzer (APA) has been widely used to evaluate hot-mix asphalt (HMA) rutting potential in mix : design and quality control-quality assurance (QC-QA) applications, because the APA testing and its data analyses are : relatively si...

  10. Advanced road scene image segmentation and pavement evaluation using neural networks.

    Science.gov (United States)

    2010-01-01

    The current project, funded by MIOH-UTC for the period 9/1/2009-8/31/2010, continues our : efforts in designing an image processing based pavement inspection system for the : assessment of highway surface conditions. One of the most important tasks i...

  11. Technical solutions to improve performance of the recycled cement concrete aggregates for durable road pavements

    OpenAIRE

    MUSCALU, Marius; RADU, Andrei; LUNGU, Irina; TARANU, Nicolae; BUDESCU, Mihai; CAZACLIU, Bogdan

    2013-01-01

    This paper presents the results of the research analyses and laboratory studies, aiming to develop design guidelines and suitable technologies for the construction of durable and environmental friendly rigid pavements by using recycled cement concrete, resulted from various demolition works. Various recycling principles and technologies, specific laboratory methods of improved technical solutions to enhance wear coefficients, density homogeneity, mixture contamination and water absorption ...

  12. Performance evaluation of Arizona's LTPP SPS-1 project : strategic study of flexible pavement structural factors.

    Science.gov (United States)

    2012-01-01

    As part of the Long Term Pavement Performance (LTPP) Program, Arizona DOT constructed 16 SPS-1 test : sections on U.S. Route 93 near Kingman. The SPS-1 study was designed to study a variety of structural : sections in new asphalt concrete constructio...

  13. Structural evaluation of asphalt pavements with full-depth reclaimed base.

    Science.gov (United States)

    2012-12-01

    Currently, MnDOT pavement design recommends granular equivalency, GE = 1.0 for non-stabilized full-depth : reclamation (FDR) material, which is equivalent to class 5 material. For stabilized full-depth reclamation (SFDR), : there was no guideline for...

  14. Application of Linear Viscoelastic Properties in Semianalytical Finite Element Method with Recursive Time Integration to Analyze Asphalt Pavement Structure

    Directory of Open Access Journals (Sweden)

    Pengfei Liu

    2018-01-01

    Full Text Available Traditionally, asphalt pavements are considered as linear elastic materials in finite element (FE method to save computational time for engineering design. However, asphalt mixture exhibits linear viscoelasticity at small strain and low temperature. Therefore, the results derived from the elastic analysis will inevitably lead to discrepancies from reality. Currently, several FE programs have already adopted viscoelasticity, but the high hardware demands and long execution times render them suitable primarily for research purposes. Semianalytical finite element method (SAFEM was proposed to solve the abovementioned problem. The SAFEM is a three-dimensional FE algorithm that only requires a two-dimensional mesh by incorporating the Fourier series in the third dimension, which can significantly reduce the computational time. This paper describes the development of SAFEM to capture the viscoelastic property of asphalt pavements by using a recursive formulation. The formulation is verified by comparison with the commercial FE software ABAQUS. An application example is presented for simulations of creep deformation of the asphalt pavement. The investigation shows that the SAFEM is an efficient tool for pavement engineers to fast and reliably predict asphalt pavement responses; furthermore, the SAFEM provides a flexible, robust platform for the future development in the numerical simulation of asphalt pavements.

  15. Asphalt Concrete Overlay Optimization Based on Pavement Performance Models

    Directory of Open Access Journals (Sweden)

    Jan Mikolaj

    2017-01-01

    Full Text Available The life cycle length of pavement with asphalt concrete material (ACM surfacing is significantly influenced, in addition to transport loading and climatic conditions, by design method and rehabilitation timing. Appropriate overlay thickness calculation and estimation of optimal rehabilitation time are crucial to maximizing life cycle length and, concurrently, reducing road administration costs and road user costs. This article describes a comprehensive method of ACM rehabilitation design. For optimization of life cycle cost analysis (LCCA based design, mathematical analytical solution in combination with experimental verification of physical, mechanical, and fatigue characteristics is utilized. Pavement performance, that is, functions mathematically describing pavement’s degradation characteristics of operational capability, is represented by longitudinal and transverse unevenness; these are used to describe relations between traffic loading and pavement’s bearing capacity on 1 : 1 scale. Optimizing of rehabilitation plan is carried out by making a cost benefit analysis (CBA for several rehabilitation scenarios in which different rehabilitation timing produces different capital cost requirements and social benefits. Rehabilitation scenarios differ in technology, the design of which needs to be mathematically optimized, and timing of rehabilitation execution. This article includes a case study for the sake of illustration of practical results and verification of applicability of used methodology.

  16. Predictability of steel containment response near failure track 3 - structural integrity, dynamic behavior, and seismic design

    International Nuclear Information System (INIS)

    Costello, J.F.; Ludwigsen, J.S.; Luk, V.K.; Hessheimer, M.F.

    2000-01-01

    The Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission Office of Nuclear Regulatory Research, are co-sponsoring and jointly funding a Cooperative Containment Research Program at Sandia National Laboratories, Albuquerque, New Mexico, USA. As a part of this program, a steel containment vessel model and contact structure assembly was tested to failure with over pressurization at Sandia on December 11--12, 1996. The steel containment vessel model was a mixed-scale model (1:10 in geometry and 1:4 in shell thickness) of a steel containment for an improved Mark-II Boiling Water Reactor plant in Japan. The contact structure, which is a thick, bell-shaped steel shell separated at a nominally uniform distance from the model, provides a simplified representation of features of the concrete reactor shield building in the actual plant. The objective of the internal pressurization test was to provide measurement data of the structural response of the model up to its failure in order to validate analytical modeling, to find its pressure capacity, and to observe the failure model and mechanisms

  17. Knowledge Discovery and Pavement Performance : Intelligent Data Mining

    NARCIS (Netherlands)

    Miradi, M.

    2009-01-01

    The main goal of the study was to discover knowledge from data about asphalt road pavement problems to achieve a better understanding of the behavior of them and via this understanding improve pavement quality and enhance its lifespan. Four pavement problems were chosen to be investigated; raveling

  18. Estimating the benefits of improved drainage on pavement ...

    African Journals Online (AJOL)

    The drainage quality is an important parameter which affects the performance of highway pavements. In India, since last few years considerable importance has been given to the drainage as per of pavement. A poor quality of drainage results in premature deterioration of the pavement structure and necessitating large ...

  19. Effect of training algorithms on neural networks aided pavement ...

    African Journals Online (AJOL)

    Routine pavement maintenance necessitates present structural diagnosis and condition evaluation of pavements by employing non-destructive test equipment such as the Falling Weight Deflectometer (FWD). FWD testing of pavements involves measuring time-domain surface deflections resulting from applied impulse ...

  20. Pavement sound absorption measurements in the U.S.

    Science.gov (United States)

    2012-08-19

    In the U.S., the topic of pavement sound absorption in regard to tire-pavement noise has shown increased interest and research over the last several years. Four types of pavement sound absorption measurements with various applications are discussed: ...

  1. Success and failure factors in the regional health information system design process--results from a constructive evaluation study.

    Science.gov (United States)

    Nykänen, P; Karimaa, E

    2006-01-01

    To identify success and failure factors in the design process of a regional health information system. A constructive evaluation study including interviews, observations, usability study and document analysis. Modelling was found to be a key element for the successful implementation of a health information system. The developed service chain model helped to define use cases and to implement seamless service chains. User participation in the design process was a success factor resulting in good user acceptance and signs of positive impacts on work practices. Evaluation study also helped system developers to guide the system's further development. An important failure factor identified was the lack of semantic interoperability of the system components. The results emphasize the socio-technical nature of health information systems. The starting point for development should be thorough insight into the health care work practices where the information systems are to be used. Successful system design should start from modelling of work processes, data and information flows and definition of concepts and their relations. Health informatics as a scientific discipline provides theories and models for the design and development process.

  2. Effectiveness of various public private partnership pavement rehabilitation treatments: A big data informatics survival analysis of pavement service life : final report.

    Science.gov (United States)

    2017-09-29

    Past research efforts have used a wide variety of methodological approaches to analyze pavement performance indicators, pavement rehabilitation treatments, and pavement service life. Using big data informatics methods, the intent of this study is to ...

  3. Rationale, design and baseline results of the Treatment Optimisation in Primary care of Heart failure in the Utrecht region (TOPHU) study : a cluster randomised controlled trial

    NARCIS (Netherlands)

    Valk, Mark J.; Hoes, Arno W.; Mosterd, Arend; Landman, Marcel A.; Broekhuizen, Berna D L; Rutten, Frans H.

    2015-01-01

    BACKGROUND: Heart failure (HF) is mainly detected and managed in primary care, but the care is considered suboptimal. We present the rationale, design and baseline results of the Treatment Optimisation in Primary care of Heart failure in the Utrecht region (TOPHU) study. In this study we assess the

  4. Design and Environmental Factors Contributing to the Failure of Thermal Barrier Coating Systems

    Science.gov (United States)

    Weeks, Matthew David

    Gas turbine engines are a staple of 21st century air and sea propulsion systems and are also a critical component in large-scale electricity generation. The hot-section components of these engines are protected by a complex ceramic and metal multi-layer coating called a thermal barrier coating (TBC) system. The failure of TBC systems occurs as a result of both thermo-chemical and thermo-mechanical degradation. This research involves exploring both of these mechanisms for two distinctly different issues. The United States Navy is currently making a push to implement the use of alternative fuels by 2012, but the use of these fuels (syngas, high hydrogen content, and alternatives to JP-8) presents significant materials durability challenges. Initial data suggests that high water vapor levels, high sulfur concentrations, and ash deposits from fuel impurities lead to unique, and severe, degradation modes. This research is aimed at addressing the effects of differing combustion environment characteristics on the corrosion and oxidation of TBC systems. On the industrial front, there is a constant driver to better understand and predict coating failure, particularly in air-plasma sprayed (APS) TBC systems. The morphology of the metal-ceramic interface is known to play a key role in the generation of compressive and tensile stresses that eventually cause coating failure in typical engine environments. Experimental evidence and field experience have shown that a tortuous interface is generally beneficial to coating lifetime. Nevertheless, for the past 40 years engineers have struggled to find a functional correlation between BC topology and coating system lifetime. This document also addresses the progress that has been made toward the establishment of this functional correlation.

  5. Fracture resistance and failure modes of polymer infiltrated ceramic endocrown restorations with variations in margin design and occlusal thickness.

    Science.gov (United States)

    Taha, Doaa; Spintzyk, Sebastian; Schille, Christine; Sabet, Ahmed; Wahsh, Marwa; Salah, Tarek; Geis-Gerstorfer, Jürgen

    2017-12-11

    The purpose of this in vitro study was to assess the effect of varying the margin designs and the occlusal thicknesses on the fracture resistance and mode of failures of endodontically treated teeth restored with polymer infiltrated ceramic endocrown restorations. Root canal treated mandibular molars were divided into four groups (n=8) and were prepared to receive Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) fabricated polymer infiltrated ceramic endocrowns (ENAMIC blocks). Group B2 represents teeth prepared with a butt joint design receiving endocrowns with 2mm occlusal thickness and the same for group B3.5 but with 3.5mm occlusal thickness. Group S2 represents teeth prepared with 1mm shoulder finish line receiving endocrowns with 2mm occlusal thickness and the same for group S3.5 but with 3.5mm occlusal thickness. After cementation and thermal aging, fracture resistance test was performed and failure modes were observed. Group S3.5 showed the highest mean fracture load value (1.27±0.31kN). Endocrowns with shoulder finish line had significantly higher mean fracture resistance values than endocrowns with butt margin (p<0.05). However, the results were not statistically significant regarding the restoration thickness. Evaluation of the fracture modes revealed no statistically significant difference between the modes of failure of tested groups. For the restoration of endodontically treated teeth, adding a short axial wall and shoulder finish line can increase the fracture resistance. However, further investigations, especially the fatigue behavior, are needed to ensure this effect applies with small increases of restoration thickness. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  6. Pathology and failure in the design and implementation of adaptive management

    Science.gov (United States)

    Allen, Craig R.; Gunderson, Lance H.

    2011-01-01

    The conceptual underpinnings for adaptive management are simple; there will always be inherent uncertainty and unpredictability in the dynamics and behavior of complex ecological systems as a result non-linear interactions among components and emergence, yet management decisions must still be made. The strength of adaptive management is in the recognition and confrontation of such uncertainty. Rather than ignore uncertainty, or use it to preclude management actions, adaptive management can foster resilience and flexibility to cope with an uncertain future, and develop safe to fail management approaches that acknowledge inevitable changes and surprises. Since its initial introduction, adaptive management has been hailed as a solution to endless trial and error approaches to complex natural resource management challenges. However, its implementation has failed more often than not. It does not produce easy answers, and it is appropriate in only a subset of natural resource management problems. Clearly adaptive management has great potential when applied appropriately. Just as clearly adaptive management has seemingly failed to live up to its high expectations. Why? We outline nine pathologies and challenges that can lead to failure in adaptive management programs. We focus on general sources of failures in adaptive management, so that others can avoid these pitfalls in the future. Adaptive management can be a powerful and beneficial tool when applied correctly to appropriate management problems; the challenge is to keep the concept of adaptive management from being hijacked for inappropriate use.

  7. Optical microtopographic inspection of asphalt pavement surfaces

    Science.gov (United States)

    Costa, Manuel F. M.; Freitas, E. F.; Torres, H.; Cerezo, V.

    2017-08-01

    Microtopographic and rugometric characterization of surfaces is routinely and effectively performed non-invasively by a number of different optical methods. Rough surfaces are also inspected using optical profilometers and microtopographer. The characterization of road asphalt pavement surfaces produced in different ways and compositions is fundamental for economical and safety reasons. Having complex structures, including topographically with different ranges of form error and roughness, the inspection of asphalt pavement surfaces is difficult to perform non-invasively. In this communication we will report on the optical non-contact rugometric characterization of the surface of different types of road pavements performed at the Microtopography Laboratory of the Physics Department of the University of Minho.

  8. HYBRID HUMAN-ARTIFICIAL INTELLIGENCE APPROACH FOR PAVEMENT DISTRESS ASSESSMENT (PICUCHA

    Directory of Open Access Journals (Sweden)

    Reus Salini

    2017-07-01

    Full Text Available The pavement surface condition assessment is a critical component for a proper pavement management system as well as for pavement rehabilitation design. A number of devices were developed to automatically record surface distresses in a continuous survey mode, but the software required for automatic distress identification remains a big challenge. In this study, a new method named PICture Unsupervised Classification with Human Analysis (PICUCHA is proposed to circumvent many of the limitations of existing approaches, based on a combination of human and artificial intelligence. It was designed from scratch to be capable to identify sealed and unsealed cracks, potholes, patches, different types of pavements and others. The self-learning algorithms do not use any distresses predefinition and can process images taken by cameras with different brands, technologies and resolution. This study describes some key aspects of the new method and provides examples in which PICUCHA was tested in real conditions showing accuracy up to 96.9% in image pattern detection and classification.

  9. Developing A Framework for Low-Volume Road Implementation of Pervious Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Sonia Rahman, BSc

    2015-03-01

    Full Text Available Pervious concrete pavement is one of the promising pavement technologies, as it can help overcome traditional pavement environmental impacts, assist with stormwater management, and provide an effective low impact development solution. There are many benefits associated with pervious concrete pavement such as assisting with water filtration, absorbing heavy metals and reducing pollution. The most significant aspect, which draws the attention of environmental agencies and cities and municipalities, is its ability to reduce storm water runoff. Pervious concrete is documented as the paramount solution in storm water management by the United States Environmental Protection Agency. Though it has been used in the southern United States for years, the practice of using pervious concrete is more recent in northern climates where freeze thaw is observed. In Canada, several pervious concrete parking lots have been constructed over the past few years. However barriers exist for implementing the technology, as designers are not always fully informed on the various functional and structural design considerations. In this paper, a framework is developed to identify how pervious concrete can be integrated into low-volume infrastructure. This paper also summarizes the structural performance and drainage characteristics of pervious concrete parking lots constructed in various provinces of Canada, demonstrating the viability of pervious concrete for low-volume northern applications.

  10. A randomized trial of heart failure disease management in skilled nursing facilities: design and rationale.

    Science.gov (United States)

    Boxer, Rebecca S; Dolansky, Mary A; Bodnar, Christine A; Singer, Mendel E; Albert, Jeffery M; Gravenstein, Stefan

    2013-09-01

    Heart failure (HF) disease management can improve health outcomes for older community dwelling patients with heart failure. HF disease management has not been studied in skilled nursing facilities, a major site of transitional care for older adults. The objective of this trial is to investigate if a HF- disease management program (HF-DMP) in skilled nursing facilities (SNF)s will decrease all-cause rehospitalizations for the first 60 days post-SNF admission. The trial is a randomized cluster trial to be conducted in 12 for-profit SNF in the greater Cleveland area. The study population is inclusive of patients with HF regardless of ejection fraction but excludes those patients on dialysis and with a life expectancy of 6 months or less. The HF-DMP includes 7 elements considered standard of care for patients with HF documentation of left ventricular function, tracking of weight and symptoms, medication titration, discharge instructions, 7-day follow-up appointment post-SNF discharge, and patient education. The HF-DMP is conducted by a research nurse tasked with adhering to each element of the program and regularly audited to maintain fidelity of the program. Additional outcomes include health status, self-care management, and discharge destination. The SNF-Connect Trial is the first trial of its kind to assess if a HF-DMP will improve outcomes for patients in SNFs. This trial will provide evidence on the effectiveness of HF-DMP to improve outcomes for older frail HF patients undergoing postacute rehabilitation. Copyright © 2013 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

  11. A MECHANISTIC-EMPIRICAL IMPACT ANALYSIS OF DIFFERENT TRUCK CONFIGURATIONS ON A JOINTED PLAIN CONCRETE PAVEMENT (JPCP

    Directory of Open Access Journals (Sweden)

    Lubinda F. Walubita

    2017-12-01

    Full Text Available Until the last decade, the 1993 American Association of State Highway and Transportation Officials (AASHTO design guide has been traditionally used for the design of flexible and rigid pavements in the USA and some parts of the world. However, because of its inability to meet the new traffic and material challenges, a Mechanistic Empirical Pavement Design Guide (MEPDG was introduced based on an NCHRP 1-37 A study conducted in 2004. This study used the MEPDG software and associated models to determine, through comparative truck damage analysis, the effects of nine different truck configurations on a 12 inch-jointed plain concrete pavement (JPCP. The study recorded truck damages at the end of each analysis period (40 years and comparatively analyzed the relative pavement damage in terms of fatigue cracking, faulting, and surface roughness. The results indicated that the most critical damage to the concrete pavement was caused by truck cases with high and uneven load distribution and relatively smaller size axles group (e.g. tandem. Other key findings included the following; (1 increase in damage when the truckloads were shifted between the same size axles, (2 decrease in truck damage when the truckloads were shifted from tandem axle to quad axles, and (3 no change in truck damage when the axle spacing was increased between wheels of a quad axle.

  12. Tyre-pavement interface contact stresses on flexible pavements - quo vadis?

    CSIR Research Space (South Africa)

    De Beer, Morris

    2004-09-01

    Full Text Available on tyre inflation pressure on this route is also given. The paper also discusses an improved definition of the actual tyre/pavement interaction of modern heavy vehicles and their loads on the current flexible road infrastructure....

  13. Development of Pavement Condition Index Model Using PAVER 6.5.7 for Flexible Pavement Urban Roads in Kerbala City

    Directory of Open Access Journals (Sweden)

    Hussein Ali Ewadh

    2017-08-01

    Full Text Available The pavement condition index (PCI is an important factor indicating pavement condition of roads. The pavement is one of the basic parts of the road infrastructure. Accordingly the aim of this paper is to develop a pavement condition index model using PAVER 6.5.7 for a flexible pavement urban roads in the Kerbala city center. The development model is depending on the PCI value of 109 sample sections having 57.8 km length, Data collected for pavement distress (type, dimension, and severity were used to find PCI. The filtering and outlier analysis was done by using a polynomial (fourth-degree constrained least squared for statistical process. These processes were done by (PAVER 6.5.7 software. The result of the prediction model of PCI shows that it is valid to be used in the prediction of the condition of pavement for the same family type

  14. Energy harvesting in pavement from passing vehicles with piezoelectric composite plate for ice melting

    Science.gov (United States)

    Faisal, Farjana; Wu, Nan; Kapoor, Kartik

    2016-04-01

    An energy harvester in the road pavement made from a piezoelectric composite plate is designed and studied to collect energy from the passing vehicles for the ice melting aim. Piezoelectric material has the ability to produce electric charge on its surface when strain takes place due to any external loading. Based on this property, a rectangular composite plate harvester is developed consisting of piezoelectric material as the energy generation coating layer and A514 steel as the substrate layer to realize the energy harvesting process from the variable pressure generated in the road pavement by passing vehicles. Based on Westergaards stress model, a numerical model is developed to calculate the three dimensional stress distribution in the pavement. Numerical simulations are conducted to study the optimization of various parameters of the harvester, such as depth of the harvester in the pavement, length and width as well as thicknesses of piezoelectric layer and the substrate. By taking in to consideration the maximum stress that can be sustained by both of the piezoelectric material and also the substrate material, an optimum design of the piezoelectric couple composite plate energy harvester is suggested. It is seen that the maximum output power, which can be generated by a single patch of 0.2m*0.2m*0.0026m dimension with a vehicle passing at 22.2 m/s, can reach up to 23.36 W. With the well-designed pavement energy harvesters, it is feasible to collect enough energy to rise the temperature of the ice with the thickness of 1cm covering a 5m width road by 20 degree Celsius within 2.5 hours. This technique can be applied to melt the ice on the roads and bridges especially in cold countries.

  15. Rationale and Design of the Reduce Elevated Left Atrial Pressure in Patients With Heart Failure (Reduce LAP-HF) Trial.

    Science.gov (United States)

    Hasenfuss, Gerd; Gustafsson, Finn; Kaye, David; Shah, Sanjiv J; Burkhoff, Dan; Reymond, Marie-Christine; Komtebedde, Jan; Hünlich, Mark

    2015-07-01

    Heart failure with preserved ejection fraction (HFpEF) is characterized by elevated left atrial pressure during rest and/or exercise. The Reduce LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial will evaluate the safety and performance of the Interatrial Shunt Device (IASD) System II, designed to directly reduce elevated left atrial pressure, in patients with HFpEF. The Reduce LAP-HF Trial is a prospective, nonrandomized, open-label trial to evaluate a novel device that creates a small permanent shunt at the level of the atria. A minimum of 60 patients with ejection fraction ≥40% and New York Heart Association functional class III or IV heart failure with a pulmonary capillary wedge pressure (PCWP) ≥15 mm Hg at rest or ≥25 mm Hg during supine bike exercise will be implanted with an IASD System II, and followed for 6 months to assess the primary and secondary end points. Safety and standard clinical follow-up will continue through 3 years after implantation. Primary outcome measures for safety are periprocedural and 6-month major adverse cardiac and cerebrovascular events (MACCE) and systemic embolic events (excluding pulmonary thromboembolism). MACCE include death, stroke, myocardial infarction, or requirement of implant removal. Primary outcome measures for device performance include success of device implantation, reduction of PCWP at rest and during exercise, and demonstration of left-to-right flow through the device. Key secondary end points include exercise tolerance, quality of life, and the incidence of heart failure hospitalization. Reduce LAP-HF is the first trial intended to lower left atrial pressure in HFpEF by means of creating a permanent shunt through the atrial septum with the use of a device. Although the trial is primarily designed to study safety and device performance, we also test the pathophysiologic hypothesis that reduction of left atrial pressure will improve symptoms and quality of life in patients

  16. Tools for Economic Analysis of Patient Management Interventions in Heart Failure Cost-Effectiveness Model: A Web-based program designed to evaluate the cost-effectiveness of disease management programs in heart failure.

    Science.gov (United States)

    Reed, Shelby D; Neilson, Matthew P; Gardner, Matthew; Li, Yanhong; Briggs, Andrew H; Polsky, Daniel E; Graham, Felicia L; Bowers, Margaret T; Paul, Sara C; Granger, Bradi B; Schulman, Kevin A; Whellan, David J; Riegel, Barbara; Levy, Wayne C

    2015-11-01

    Heart failure disease management programs can influence medical resource use and quality-adjusted survival. Because projecting long-term costs and survival is challenging, a consistent and valid approach to extrapolating short-term outcomes would be valuable. We developed the Tools for Economic Analysis of Patient Management Interventions in Heart Failure Cost-Effectiveness Model, a Web-based simulation tool designed to integrate data on demographic, clinical, and laboratory characteristics; use of evidence-based medications; and costs to generate predicted outcomes. Survival projections are based on a modified Seattle Heart Failure Model. Projections of resource use and quality of life are modeled using relationships with time-varying Seattle Heart Failure Model scores. The model can be used to evaluate parallel-group and single-cohort study designs and hypothetical programs. Simulations consist of 10,000 pairs of virtual cohorts used to generate estimates of resource use, costs, survival, and incremental cost-effectiveness ratios from user inputs. The model demonstrated acceptable internal and external validity in replicating resource use, costs, and survival estimates from 3 clinical trials. Simulations to evaluate the cost-effectiveness of heart failure disease management programs across 3 scenarios demonstrate how the model can be used to design a program in which short-term improvements in functioning and use of evidence-based treatments are sufficient to demonstrate good long-term value to the health care system. The Tools for Economic Analysis of Patient Management Interventions in Heart Failure Cost-Effectiveness Model provides researchers and providers with a tool for conducting long-term cost-effectiveness analyses of disease management programs in heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Utilize Cementitious High Carbon Fly Ash (CHCFA) to Stabilize Cold In-Place Recycled (CIR) Asphalt Pavement as Base Coarse

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Haifang; Li, Xiaojun; Edil, Tuncer; O' Donnell, Jonathan; Danda, Swapna

    2011-02-05

    The purpose of this study was to evaluate the performance of cementitious high carbon fly ash (CHCFA) stabilized recycled asphalt pavement as a base course material in a real world setting. Three test road cells were built at MnROAD facility in Minnesota. These cells have the same asphalt surface layers, subbases, and subgrades, but three different base courses: conventional crushed aggregates, untreated recycled pavement materials (RPM), and CHCFA stabilized RPM materials. During and after the construction of the three cells, laboratory and field tests were carried out to characterize the material properties. The test results were used in the mechanistic-empirical pavement design guide (MEPDG) to predict the pavement performance. Based on the performance prediction, the life cycle analyses of cost, energy consumption, and greenhouse gasses were performed. The leaching impacts of these three types of base materials were compared. The laboratory and field tests showed that fly ash stabilized RPM had higher modulus than crushed aggregate and RPM did. Based on the MEPDG performance prediction, the service life of the Cell 79 containing fly ash stabilized RPM, is 23.5 years, which is about twice the service life (11 years) of the Cell 77 with RPM base, and about three times the service life (7.5 years) of the Cell 78 with crushed aggregate base. The life cycle analysis indicated that the usage of the fly ash stabilized RPM as the base of the flexible pavement can significantly reduce the life cycle cost, the energy consumption, the greenhouse gases emission. Concentrations of many trace elements, particularly those with relatively low water quality standards, diminish over time as water flows through the pavement profile. For many elements, concentrations below US water drinking water quality standards are attained at the bottom of the pavement profile within 2-4 pore volumes of flow.

  18. Integration of pavement cracking prediction model with asset management and vehicle-infrastructure interaction models.

    Science.gov (United States)

    2015-01-01

    Not long after the construction of a pavement or a new pavement surface, various : forms of deterioration begin to accumulate due to the harsh effects of traffic loading : combined with weathering action. In a recent NEXTRANS project, a pavement crac...

  19. Multi-resolution information mining and a computer vision approach to pavement condition distress analysis.

    Science.gov (United States)

    2014-07-01

    Pavement Condition surveys are carried out periodically to gather information on pavement distresses that will guide decision-making for maintenance and preservation. Traditional methods involve manual pavement inspections which are time-consuming : ...

  20. On-board sound intensity tire-pavement noise study in North Carolina.

    Science.gov (United States)

    2011-12-01

    "This research investigated tire-pavement noise on various types of pavements across North Carolina by using On- : Board Sound Intensity (OBSI) method. To mitigate traffic noise, quieter pavement may provide advantages that : noise barriers cannot. T...

  1. Developing a network-level structural capacity index for structural evaluation of pavements.

    Science.gov (United States)

    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 pavements structural condition in pavement management applications. The primary goal of network-level...

  2. Predicting pavement condition index using international roughness index in Washington DC.

    Science.gov (United States)

    2014-09-01

    A number of pavement condition indices are used to conduct pavement management assessments, two of which are the : International Roughness Index (IRI) and Pavement Condition Index (PCI). The IRI is typically measured using specialized : equipment tha...

  3. Analysis of the usage of rubberized asphalt in hot mix asphalt using Reclaimed Asphalt Pavement (RAP)

    Science.gov (United States)

    Dwidarma Nataadmadja, Adelia; Prahara, Eduardi; Sumbung, Pierre Christian

    2017-12-01

    There has been an increasing demand in using more environmentally friendly materials in pavement construction. One of the alternative materials that have been widely used is the Reclaimed Asphalt Pavement (RAP) aggregates. The RAP aggregates are derived from the crushed and screened pavement materials that contain asphalt and aggregates. This material is usually combined with natural aggregates and virgin asphalt binder to construct a new pavement. There have been numerous positive feedbacks in using this material although RAP aggregates also have certain weaknesses, such as questionable interaction between virgin and recycled materials and increased stiffness of RAP binder. Moreover, there has been a push on using rubber as an additive to asphalt binder to improve the welfare of rubber farmers. This research combines the usage of both latex and RAP as the ingredients to design hot mix asphalt (HMA) as latex could help in improving the flexibility of HMA and the interaction between the virgin and recycled materials. The main objective of this research is to find a suitable percentage of RAP aggregates to be used in HMA with certain percentage of latex as the binder additive.

  4. Cracking of open traffic rigid pavement

    Directory of Open Access Journals (Sweden)

    Niken Chatarina

    2017-01-01

    Full Text Available The research is done by observing the growth of real structure cracking in Natar, Lampung, Indonesia compared to C. Niken’s et al research and literature study. The rigid pavement was done with open traffic system. There are two main crack types on Natar rigid pavement: cracks cross the road, and cracks spreads on rigid pavement surface. The observation of cracks was analyzed by analyzing material, casting, curing, loading and shrinkage mechanism. The relationship between these analysis and shrinkage mechanism was studied in concrete micro structure. Open traffic make hydration process occur under vibration; therefore, fresh concrete was compressed and tensioned alternately since beginning. High temperature together with compression, cement dissociation, the growth of Ca2+ at very early age leads abnormal swelling. No prevention from outside water movement leads hydration process occur with limited water which caused spreads fine cracks. Limited water improves shrinkage and plastic phase becomes shorter; therefore, rigid pavement can’t accommodate the abnormal swelling and shrinking alternately and creates the spread of cracks. Discontinuing casting the concrete makes both mix under different condition, the first is shrink and the second is swell and creates weak line on the border; so, the cracks appear as cracks across the road.

  5. "Full-Scale Testing of Pavement Response"

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ekdahl, Peter

    1998-01-01

    methods for determining stresses, strains and deflections in pavement structurers.Falling Weight Deflectometer (FWD) test were done on the test sections, and stresses and strains were measured both under FWD loading and under a rolling wheel load. Different back-analysis procedures were used to derive...

  6. Microstructural pavement material characterization: some examples

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2008-07-01

    Full Text Available The utilisation of advanced measurement techniques should assist in the characterization of pavement materials at a micro-scale. The motivating factor for such an approach is that material properties at the micro-level have a critical role...

  7. The Reflective Cracking in Flexible Pavements

    Directory of Open Access Journals (Sweden)

    Pais Jorge

    2013-07-01

    Full Text Available Reflective cracking is a major concern for engineers facing the problem of road maintenance and rehabilitation. The problem appears due to the presence of cracks in the old pavement layers that propagate into the pavement overlay layer when traffic load passes over the cracks and due to the temperature variation. The stress concentration in the overlay just above the existing cracks is responsible for the appearance and crack propagation throughout the overlay. The analysis of the reflective cracking phenomenon is usually made by numerical modeling simulating the presence of cracks in the existing pavement and the stress concentration in the crack tip is assessed to predict either the cracking propagation rate or the expected fatigue life of the overlay. Numerical modeling to study reflective cracking is made by simulating one crack in the existing pavement and the loading is usually applied considering the shear mode of crack opening. Sometimes the simulation considers the mode I of crack opening, mainly when temperature effects are predominant.

  8. Pavement behaviour under the super single tyre

    CSIR Research Space (South Africa)

    Viljoen, AW

    1982-06-01

    Full Text Available Pavement behaviour under the super single tyre (SST) was investigated and compared with that under a conventional dual tyre (CDT). Contact areas and contact pressures over a range of loading conditions were measured and compared. Two approaches were...

  9. Lessons learned : pavement marking warranty contract.

    Science.gov (United States)

    2013-12-01

    In 2012, UDOT implemented a performance-based warranty on a portion of an I-15 pavement marking : project. The awarded contract requested a contractor warranty on the implemented markings for a total : duration of six years. This is the first time th...

  10. Finite-element analysis of failure of the Capital Hip designs.

    NARCIS (Netherlands)

    Janssen, D.; Aquarius, R.J.M.; Stolk, J.; Verdonschot, N.J.J.

    2005-01-01

    The Capital Hip implant was a Charnley-based system which included a flanged and a roundback stem, both of which were available in stainless steel and titanium. The system was withdrawn from the market because of its inferior performance. However, all four of the designs did not produce poor rates

  11. Telemonitoring after discharge from hospital with heart failure: cost-effectiveness modelling of alternative service designs.

    Science.gov (United States)

    Thokala, Praveen; Baalbaki, Hassan; Brennan, Alan; Pandor, Abdullah; Stevens, John W; Gomersall, Tim; Wang, Jenny; Bakhai, Ameet; Al-Mohammad, Abdallah; Cleland, John; Cowie, Martin R; Wong, Ruth

    2013-09-18

    To estimate the cost-effectiveness of remote monitoring strategies versus usual care for adults recently discharged after a heart failure (HF) exacerbation. Decision analysis modelling of cost-effectiveness using secondary data sources. Acute hospitals in the UK. Patients recently discharged (within 28 days) after a HF exacerbation. Structured telephone support (STS) via human to machine (STS HM) interface, (2) STS via human to human (STS HH) contact and (3) home telemonitoring (TM), compared with (4) usual care. The incremental cost per quality-adjusted life year (QALY) gained by each strategy compared to the next most effective alternative and the probability of each strategy being cost-effective at varying willingness to pay per QALY gained. TM was the most cost-effective strategy in the scenario using these base case costs. Compared with usual care, TM had an estimated incremental cost effectiveness ratio (ICER) of £11 873/QALY, whereas STS HH had an ICER of £228 035/QALY against TM. STS HM was dominated by usual care. Threshold analysis suggested that the monthly cost of TM has to be higher than £390 to have an ICER greater than £20 000/QALY against STS HH. Scenario analyses performed using higher costs of usual care, higher costs of STS HH and lower costs of TM do not substantially change the conclusions. Cost-effectiveness analyses suggest that TM was an optimal strategy in most scenarios, but there is considerable uncertainty in relation to clear descriptions of the interventions and robust estimation of costs.

  12. A cluster randomized controlled trial of a clinical pathway for hospital treatment of heart failure: study design and population

    Directory of Open Access Journals (Sweden)

    Gardini Andrea

    2007-11-01

    Full Text Available Abstract Background The hospital treatment of heart failure frequently does not follow published guidelines, potentially contributing to the high morbidity, mortality and economic cost of this disorder. Consequently the development of clinical pathways has the potential to reduce the current variability in care, enhance guideline adherence, and improve outcomes for patients. Despite enthusiasm and diffusion, the widespread acceptance of clinical pathways remain questionable because very little prospective controlled data demonstrated their effectiveness. The Experimental Prospective Study on the Effectiveness and Efficiency of the Implementation of Clinical Pathways was designed in order to conduct a rigorous evaluation of clinical pathways in hospital treatment of acute heart failure. The primary objective of the trial was to evaluate the effectiveness of the implementation of clinical pathways for hospital treatment of heart failure in Italian hospitals. Methods/design Two-arm, cluster-randomized trial. 14 community hospitals were randomized either to arm 1 (clinical pathway: appropriate use of practice guidelines and supplies of drugs and ancillary services, new organization and procedures, patient education, etc. or to arm 2 (no intervention, usual care. 424 patients sample (212 in each group, 80% of power at the 5% significance level (two-sided. The primary outcome measure is in-hospital mortality. We will also analyze the impact of the clinical pathways comparing the length and the appropriateness of the stay, the rate of unscheduled readmissions, the customers' satisfaction and the costs treating the patients with the pathways and with the current practice along all the observation period. The quality of the care will be assessed by monitoring the use of diagnostic and therapeutic procedures during hospital stay and by measuring key quality indicators at discharge. Discussion This paper examines the design of the evaluation of a complex

  13. Design of load-to-failure tests of high-voltage insulation breaks for ITER's cryogenic network

    Science.gov (United States)

    Langeslag, S. A. E.; Rodriguez Castro, E.; Aviles Santillana, I.; Sgobba, S.; Foussat, A.

    2015-12-01

    The development of new generation superconducting magnets for fusion research, such as the ITER experiment, is largely based on coils wound with so-called cable-in-conduit conductors. The concept of the cable-in-conduit conductor is based on a direct cooling principle, by supercritical helium, flowing through the central region of the conductor, in close contact with the superconducting strands. Consequently, a direct connection exists between the electrically grounded helium coolant supply line and the highly energised magnet windings. Various insulated regions, constructed out of high-voltage insulation breaks, are put in place to isolate sectors with different electrical potential. In addition to high voltages and significant internal helium pressure, the insulation breaks will experience various mechanical forces resulting from differential thermal contraction phenomena and electro-magnetic loads. Special test equipment was designed, prepared and employed to assess the mechanical reliability of the insulation breaks. A binary test setup is proposed, where mechanical failure is assumed when leak rate of gaseous helium exceeds 10-9·Pa·m3/s. The test consists of a load-to-failure insulation break charging, in tension, while immersed in liquid nitrogen at the temperature of 77 K. Leak tightness during the test is monitored by measuring the leak rate of the gaseous helium, directly surrounding the insulation break, with respect to the existing vacuum inside the insulation break. The experimental setup is proven effective, and various insulation breaks performed beyond expectations.

  14. Benders decomposition for discrete material optimization in laminate design with local failure criteria

    DEFF Research Database (Denmark)

    Munoz, Eduardo; Stolpe, Mathias; Bendsøe, Martin P.

    2009-01-01

    in any discrete angle optimization design, or material selection problems. The mathematical modeling of this problem is more general than the one of standard topology optimization. When considering only two material candidates with a considerable difference in stiffness, it corresponds exactly...... to a topology optimization problem. The problem is modeled as a discrete design problem coming from a finite element discretization of the continuum problem. This discretization is made of shell or plate elements. For each element (selection domain), only one of the material candidates must be selected...... of the relaxed master problem and the current best compliance (weight) found get close enough with respect to certain tolerance. The method is investigated by computational means, using the finite element method to solve the analysis problems, and a commercial branch and cut method for solving the relaxed master...

  15. Design and construction of a large reinforced concrete containment model to be tested to failure

    International Nuclear Information System (INIS)

    Ucciferro, J.J.; Horschel, D.S.

    1987-01-01

    The US Nuclear Regulatory Commission is investigating the performance of LWR containments subjected to severe accidents. This work is being performed by the Containment Integrity Division at Sandia National Laboratories (Sandia). The latest research effort involves the testing of a 1/6-scale reinforced concrete containment model. The containment, which was designed and constructed by United Engineers and Constructors, is the largest and most complex model of its kind. The design and construction of the containment model are the subject of this paper. The objective of the containment model tests is to generate data that can be used to qualify methods for reliably predicting the response of LWR containment buildings to severe accident loads. The data recorded during testing include deformations and leakage past sealing surfaces, as well as strains and displacements of the containment shell

  16. ERG review of containment failure probability and repository functional design criteria

    International Nuclear Information System (INIS)

    Gopal, S.

    1986-06-01

    The Engineering Review Group (ERG) was established by the Office of Nuclear Waste Isolation (ONWI) to help evaluate engineering-related issues in the US Department of Energy's nuclear waste repository program. The June 1984 meeting of the ERG considered two topics: (1) statistical probability for containment of nuclides within the waste package and (2) repository design criteria. This report documents the ERG's comments and recommendations on these two subjects and the ONWI response to the specific points raised by ERG

  17. Controlled study of myocardial recovery after interval training in heart failure: SMARTEX-HF - rationale and design

    DEFF Research Database (Denmark)

    Støylen, Asbjørn; Conraads, Viviane; Halle, Martin

    2011-01-01

    Background: The large randomized controlled multicentre clinical trial, HF-ACTION, recently demonstrated that a programme of recommendation of regular exercise training at moderate intensity is safe, improves quality of life, and reduces the combined endpoint of all-cause death and hospitalization...... interval training at high relative intensity would yield significantly larger effects in terms of left ventricular remodelling compared to moderate continuous exercise training. Study design: In a three-armed randomized multicentre study of stable heart failure patients with left ventricular ejection...... fraction =35%, the effects of a 12-week programme of high-intensity interval training (HIT; 85-90% of peak oxygen uptake, VO(2peak)) will be compared to actual practice in Europe, represented by either an isocaloric programme of moderate continuous training (MCT; 50-60% of VO(2peak)) and a recommendation...

  18. Desarrollo de la nueva guía canadiense de diseño y gestión de infraestructura vial 2011: un resumen del estado de la práctica canadiense Development of the new 2011 canadian pavement asset design and management guide: a brief summary of canadian state-of-the-practice

    Directory of Open Access Journals (Sweden)

    Susan L Tighe

    2012-01-01

    Full Text Available En septiembre de 2009, la Asociación de Transporte de Canadá (Transportation Association of Canada, TAC comenzó a desarrollar la versión 2011 de la Guía de diseño y gestión de infraestructura vial (Pavement Asset Design and Management Guide, PADMG. El proyecto es un fondo de estudios auspiciado por más de veinte organismos públicos canadienses entre los cuales se encuentran los diez Departamentos de Transporte provinciales, varias de las principales ciudades canadienses, diversas asociaciones industriales y el gobierno federal. El proyecto ha sido conducido por un consorcio canadiense compuesto por especialistas y académicos de todo el país. El equipo está compuesto por un variado grupo de profesionales de vasta experiencia en Canadá en los diversos aspectos tratados en esta guía. La nueva Guía PADMG 2011 corresponde a una consolidación del estado de la práctica actual en Canadá en materia de diseño y gestión de pavimentos para ingenieros, autoridades, administradores y técnicos. Además, constituirá una valiosa fuente informativa para estudiantes universitarios y de institutos de formación técnica, tanto en el país como en el exterior. La guía destacará algunos aspectos industriales clave como la sustentabilidad, el cambio climático y las innovaciones. En primer lugar, este trabajo presenta un resumen de los hallazgos encontrados en una encuesta realizada por una parte interesada con el fin de determinar el actual estado de la práctica en Canadá. La información recogida por esa encuesta cubre los principales conocimientos prácticos del diseño y gestión de los pavimentos. La nueva Guía tendrá 15 capítulos que comprenden la discusión sobre los principios de la gestión de infraestructura vial, requerimientos de datos, sustentabilidad, mantenimiento, materiales, diseño de caminos para alto y bajo volumen y análisis del ciclo de vida de los diseños de los pavimentos. El borrador del PADMG 2011 fue aprobado y

  19. Effects of using silica fume and polycarboxylate-type superplasticizer on physical properties of cementitious grout mixtures for semiflexible pavement surfacing.

    Science.gov (United States)

    Koting, Suhana; Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S; Ibrahim, Mohd Rasdan; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout.

  20. Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

    Directory of Open Access Journals (Sweden)

    Suhana Koting

    2014-01-01

    Full Text Available Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout.

  1. Digital image processing as a tool for pavement distress evaluation

    Science.gov (United States)

    Georgopoulos, A.; Loizos, A.; Flouda, A.

    The information obtained through accurate condition assessment of pavement surface distress data is needed as an essential input to any decision making process concerning pavement management policy. At the same time technological advances in automated inspection systems provide the opportunity to automate the collection and evaluation of the pavement surface condition. In this paper a method developed jointly by the Laboratories of Highway Engineering and Photogrammetry of the National Technical University of Athens is described and proposed. The method involves digital image processing techniques to provide suitable digital imagery as input to specialised software developed especially for this project. This software determines objectively and fully automatically the type, the extent and the severity of surface crackings for flexible road pavements. The proposed method presenten substantial agreement, when compared with systematic visual ratings of existing pavement crackings carried out according to the internationally accepted requirements for airfield and road pavement of the Federal Aviation Administration (FAA).

  2. Geotechnical considerations of perennial failures of a highway ...

    African Journals Online (AJOL)

    The causes of frequent failures of the Kumasi – Accra highway section at Wiwiso have been investigated to offer remedial measures on future reconstruction works. The study of the highway section at Wiwiso has revea-led that pavements can undergo considerable distress when seepage control considerations are partially ...

  3. Effect of Uphill Flexible Pavements on The Damaging Effect Of Full-Trailer Trucks With Tandem Front Axles

    Directory of Open Access Journals (Sweden)

    Sabah Said Razouki

    2017-08-01

    Full Text Available The effect of traffic on flexible pavements can be expressed in terms of truck equivalence factors. This paper presents a study on the effect of uphill pavements on the damaging effect (truck equivalence factors of two types of full-trailer trucks with tandem front axles. Axle load and geometrical characteristics survey on the two types of full-trailer trucks were carried out for determining the data needed in this study. In addition, uphill slope survey in Kerbala city was done and the data of uphill slope of other Iraqi cities were obtained from previous surveys. The paper reveals that the uphill pavement gradient causes significant increase in truck equivalence factors. In addition, the research reveals that there are many factors affecting the truck equivalence factors on uphill flexible pavements, including the total weight of full-trailer, H/B ratio (height of center of gravity to the wheel base of the truck, magnitude of uphill slope, and the structural number (SN.This work shows the importance of considering the effect of uphill slope in the design of flexible pavements on steep uphill slopes.

  4. Influence of Hydrated Lime on the Properties and Permanent Deformation of the Asphalt Concrete Layers in Pavement

    Directory of Open Access Journals (Sweden)

    Al-Tameemi Ahmed F.

    2015-07-01

    Full Text Available Flexible or asphalt concrete pavement is the paving system most widely adopted all over the world. It has been recognized that there are many different types of the factors affecting the performance and durability of asphalt concrete pavement, including the service conditions, such as: the variation of temperature from mild to extremes and the repeated excessive axle loading as well as the inadequate quality of the raw materials. All of these when combined together are going to accelerate the occurrence of distresses in flexible pavement such as permanent deformation and fatigue cracking. As the result, there has an urgent need to enhance the ability of asphalt concrete mixture to resist distresses happened in pavement. Use of additives is one of the techniques adopted to improve pavement properties. It has been found that hydrated lime might be one of the effective additives because it is widely available and relatively cheap compared to other modifiers like polymers. This paper presents an experimental study of the hydrated-lime modified asphalt concrete mixtures. Five different percentages of the hydrated lime additive were investigated, namely (1, 1.5, 2, 2.5 and 3 percent. The hydrated lime additive was used as partial replacement of limestone filler by total weight of the aggregate. The designed Hot Mix Asphalt (HMA concretes are for the application of three pavement courses, i.e. Surface, Leveling and Base. These mixtures are designed and tested following Marshall procedure and uniaxial repeated loading to evaluate permanent deformation at different temperatures of 20°C, 40°C and 60°C. The experimental results show that the addition of hydrated lime as a partial replacement of ordinary limestone mineral filler results a significant improvement on mechanical properties and the resistant to permanent deformation of the designed asphalt concrete mixtures.

  5. Nature based solutions to mitigate soil sealing in urban areas: Results from a 4-year study comparing permeable, porous, and impermeable pavements.

    Science.gov (United States)

    Fini, A; Frangi, P; Mori, J; Donzelli, D; Ferrini, F

    2017-07-01

    Soil sealing is one of the most pervasive forms of soil degradation that follows urbanization and, despite innovative pavements (i.e. pervious) are being installed in urban areas to mitigate it, there is little research on the effects of pervious pavements on soil water and carbon cycle and on the physiology of urban trees. The aim of this 4-year experiment was to assess the effects of three pavements, differing in permeability to water and gases, on some soil physical parameters, and on growth and physiology of newly planted Celtis australis and Fraxinus ornus. Treatments were: 1) impermeable pavement (asphalt on concrete sub-base); 2) permeable pavement (pavers on crushed rock sub-base); 3) porous design (porous pavement on crushed rock sub-base); 4) control (unpaved soil, kept free of weed by chemical control). Soil (temperature, moisture, oxygen content and CO 2 efflux) and plant (above- and below-ground growth, leaf gas exchange, chlorophyll fluorescence, water relations) parameters were measured. All types of pavements altered the water cycle compared to unpaved soil plots, but this disturbance was less intense in porous pavements than in other soil cover types. Porous pavements allowed both higher infiltration and evaporation of water than both pavers and asphalt. Reduction of evaporative cooling from soil paved with permeable and impermeable pavements contributed to significant soil warming: at 20cm depth, soils under concrete pavers and asphalt were 4 and 5°C warmer than soil covered by porous pavements and unpaved soils, respectively. Thus, enhancing evaporation from paved soil by the use of porous pavements may contribute to mitigating urban heat islands. CO 2 greatly accumulated under impermeable and permeable pavements, but not under porous pavements, which showed CO 2 efflux rates similar to control. Soil oxygen slightly decreased only beneath asphalt. Growth of newly planted C. australis and F. ornus was little affected by pavement type. Tree

  6. COMPARISON OF LIFE CYCLE ASSESSMENT TOOLS FOR ROAD PAVEMENT INFRASTRUCTURE

    OpenAIRE

    OLIVEIRA DOS SANTOS , Joao Miguel; THYAGARAJAN , Senthilmurugan; KEIJZER , Elisabeth; FERNANDEZ FLORES , Rocio; FLINTSCH , Gerardo

    2017-01-01

    Road pavements have considerable environmental burdens associated with their initial construction, maintenance, and usage, which has led the pavement stakeholder community to congregate efforts to better understand and mitigate these negative effects. Life cycle assessment (LCA) is a versatile methodology to quantify the effect of decisions regarding the selection of resources and processes. However, there is a considerable variety of tools for conducting pavement LCA. The objective of this p...

  7. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash

    OpenAIRE

    Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

    2015-01-01

    Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone pow...

  8. Applying robust design to study the effects of stratigraphic characteristics on brittle failure and bump potential in a coal mine.

    Science.gov (United States)

    Kim, Bo-Hyun; Larson, Mark K; Lawson, Heather E

    2018-01-01

    Bumps and other types of dynamic failure have been a persistent, worldwide problem in the underground coal mining industry, spanning decades. For example, in just five states in the U.S. from 1983 to 2014, there were 388 reportable bumps. Despite significant advances in mine design tools and mining practices, these events continue to occur. Many conditions have been associated with bump potential, such as the presence of stiff units in the local geology. The effect of a stiff sandstone unit on the potential for coal bumps depends on the location of the stiff unit in the stratigraphic column, the relative stiffness and strength of other structural members, and stress concentrations caused by mining. This study describes the results of a robust design to consider the impact of different lithologic risk factors impacting dynamic failure risk. Because the inherent variability of stratigraphic characteristics in sedimentary formations, such as thickness, engineering material properties, and location, is significant and the number of influential parameters in determining a parametric study is large, it is impractical to consider every simulation case by varying each parameter individually. Therefore, to save time and honor the statistical distributions of the parameters, it is necessary to develop a robust design to collect sufficient sample data and develop a statistical analysis method to draw accurate conclusions from the collected data. In this study, orthogonal arrays, which were developed using the robust design, are used to define the combination of the (a) thickness of a stiff sandstone inserted on the top and bottom of a coal seam in a massive shale mine roof and floor, (b) location of the stiff sandstone inserted on the top and bottom of the coal seam, and (c) material properties of the stiff sandstone and contacts as interfaces using the 3-dimensional numerical model, FLAC3D. After completion of the numerical experiments, statistical and multivariate analysis

  9. Environmentally friendly pavements: Results from noise measurements 2005-2008

    OpenAIRE

    Berge, Truls Svenn; Haukland, Frode; Ustad, Asbjørn

    2009-01-01

    CPX-measurements (tyre A) have been performed on a wide range of ordinary dense Norwegian road pavements and special test pavements, as part of the R&D project “Environmental friendly pavements” initiated by the Norwegian Public Roads Administration. The following conclusions can be made from the investigation:- New dense asphalt concrete pavements can give a tyre/road noise level (CPX) of 4-8 dB(A) lower noise level, compared to a chosen reference level for a pavement of type AC 0/1...

  10. Crack identification for rigid pavements using unmanned aerial vehicles

    Science.gov (United States)

    Bahaddin Ersoz, Ahmet; Pekcan, Onur; Teke, Turker

    2017-09-01

    Pavement condition assessment is an essential piece of modern pavement management systems as rehabilitation strategies are planned based upon its outcomes. For proper evaluation of existing pavements, they must be continuously and effectively monitored using practical means. Conventionally, truck-based pavement monitoring systems have been in-use in assessing the remaining life of in-service pavements. Although such systems produce accurate results, their use can be expensive and data processing can be time consuming, which make them infeasible considering the demand for quick pavement evaluation. To overcome such problems, Unmanned Aerial Vehicles (UAVs) can be used as an alternative as they are relatively cheaper and easier-to-use. In this study, we propose a UAV based pavement crack identification system for monitoring rigid pavements’ existing conditions. The system consists of recently introduced image processing algorithms used together with conventional machine learning techniques, both of which are used to perform detection of cracks on rigid pavements’ surface and their classification. Through image processing, the distinct features of labelled crack bodies are first obtained from the UAV based images and then used for training of a Support Vector Machine (SVM) model. The performance of the developed SVM model was assessed with a field study performed along a rigid pavement exposed to low traffic and serious temperature changes. Available cracks were classified using the UAV based system and obtained results indicate it ensures a good alternative solution for pavement monitoring applications.

  11. Performance of recycled asphalt concrete airport pavement surfaces

    Science.gov (United States)

    Cline, G. D.; Hironaka, M. C.

    1986-10-01

    The objective of this research was to make an assessment of the relative performance of recycled versus new asphalt concrete pavement surfaces constructed for airport facilities. To make this assessment, pavement condition index (PCI) surveys and tests on core samples from the hot-mix recycled pavements located on the airports at Needles, California, and Valley City, North Dakota were conducted. Both pavements have a condition rating of very good. The survey and test data were compared with those for recycled highway and virgin material Navy airfield pavements. The recycle pavement at Needles is performing as good as those Navy pavements constructed with virgin material. The recycled pavement at Valley City has a higher deterioration rate than the Navy pavements but this could be attributed to the harsh climate found in North Dakota. The results of this study show that hot-mix recycling was successful at these airports but additional studies are required to determine the applicability of Asphalt Concrete (AC) recycling for reconstruction at all airports.

  12. Explaining success and failure in the commons: the configural nature of Ostrom's institutional design principles

    Directory of Open Access Journals (Sweden)

    Jacopo Alessandro Baggio

    2016-09-01

    Full Text Available Governing common pool resources (CPR in the face of disturbances such as globalization and climate change is challenging. The outcome of any CPR governance regime is the influenced by local combinations of social, institutional, and biophysical factors, as well as cross-scale interdependencies. In this study, we take a step towards understanding multiple-causation of CPR outcomes by analyzing 1 the co-occurrence of Destign Principles (DP by activity (irrigation, fishery and forestry, and 2 the combination(s of DPs leading to social and ecological success. We analyzed 69 cases pertaining to three different activities: irrigation, fishery, and forestry. We find that the importance of the design principles is dependent upon the natural and hard human made infrastructure (i.e. canals, equipment, vessels etc.. For example, clearly defined social bounduaries are important when the natural infrastructure is highly mobile (i.e. tuna fish, while monitoring is more important when the natural infrastructure is more static (i.e. forests or water contained within an irrigation system. However, we also find that congruence between local conditions and rules and proportionality between investment and extraction are key for CPR success independent from the natural and human hard made infrastructure. We further provide new visualization techniques for co-occurrence patterns and add to qualitative comparative analysis by introducing a reliability metric to deal with a large meta-analysis dataset on secondary data where information is missing or uncertain.

  13. Identification of Pavement Distress Types and Pavement Condition Evaluation Based on Network Level Inspection for Jazan City Road Network

    OpenAIRE

    M Mubaraki

    2014-01-01

    The first step in establishing a pavement management system (PMS) is road network identification. An important feature of a PMS is the ability to determine the current condition of a road network and predict its future condition. Pavement condition evaluation may involve structure, roughness, surface distress, and safety evaluation. In this study, a pavement distress condition rating procedure was used to achieve the objectives of this study. The main objectives of this study were to identify...

  14. The prevalence and management of heart failure in Dutch nursing homes; design of a multi-centre cross-sectional study

    Directory of Open Access Journals (Sweden)

    Daamen Mariëlle AMJ

    2012-06-01

    Full Text Available Abstract Background Heart failure is likely to be particularly prevalent in the nursing home population, but reliable data about the prevalence of heart failure in nursing homes are lacking. Therefore the aims of this study are to investigate (a the prevalence and management of heart failure in nursing home residents and (b the relation between heart failure and care dependency as well as heart failure and quality of life in nursing home residents. Methods/design Nursing home residents in the southern part of the Netherlands, aged over 65 years and receiving long-term somatic or psychogeriatric care will be included in the study. A panel of two cardiologists and a geriatrician will diagnose heart failure based on data collected from actual clinical examinations (including history, physical examination, ECG, cardiac markers and echocardiography, patient records and questionnaires. Care dependency will be measured using the Care Dependency Scale. To measure the quality of life of the participating residents, the Qualidem will be used for psychogeriatric residents and the SF-12 and VAS for somatic residents. Conclusion The study will provide an insight into the actual prevalence and management of heart failure in nursing home residents as well as their quality of life and care dependency. Trial registration Dutch trial register NTR2663

  15. Transitions of Care Between Acute and Chronic Heart Failure: Critical Steps in the Design of a Multidisciplinary Care Model for the Prevention of Rehospitalization.

    Science.gov (United States)

    Comín-Colet, Josep; Enjuanes, Cristina; Lupón, Josep; Cainzos-Achirica, Miguel; Badosa, Neus; Verdú, José María

    2016-10-01

    Despite advances in the treatment of heart failure, mortality, the number of readmissions, and their associated health care costs are very high. Heart failure care models inspired by the chronic care model, also known as heart failure programs or heart failure units, have shown clinical benefits in high-risk patients. However, while traditional heart failure units have focused on patients detected in the outpatient phase, the increasing pressure from hospital admissions is shifting the focus of interest toward multidisciplinary programs that concentrate on transitions of care, particularly between the acute phase and the postdischarge phase. These new integrated care models for heart failure revolve around interventions at the time of transitions of care. They are multidisciplinary and patient-centered, designed to ensure continuity of care, and have been demonstrated to reduce potentially avoidable hospital admissions. Key components of these models are early intervention during the inpatient phase, discharge planning, early postdischarge review and structured follow-up, advanced transition planning, and the involvement of physicians and nurses specialized in heart failure. It is hoped that such models will be progressively implemented across the country. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  16. The evolution of IRRR nuclear standards from the single failure criterion and their impact on system design

    International Nuclear Information System (INIS)

    Clark, D.H.

    1978-01-01

    One of the first industry standards developed in the United States to meet regulatory agency criteria for the design and installation of nuclear power plant control and instrumentation systems was prepared by the Institute of Electrical and Electronics Engineers, Inc., abbreviated IEEE. This was IEEE Std. 279, first issued in 1968. It was subsequently revised and reissued as IEEE Std. 279-1971 ''IEEE Standard: Criteria for Protection Systems for Nuclear Power Generating Stations''. Not only has the implementation of this standard had a tremendous impact on nuclear power plant design in the United States, it has been the base document from which subsequent IEEE nuclear standards have been developed. Three major concepts which are addressed by IEEE 279, and which have had a major impact upon control and instrumentation systems in nuclear power plants are the following : 1) Single failure criterion. 2) Equipment qualification. 3) Channel independence. Each of these concepts has resulted in the development of subsequent IEEE Nuclear Standards. The impact of some of these on control and instrumentation systems are discussed. (author)

  17. An assessment of SBS modified asphalt concrete pavements performance features performing numerical analysis

    Science.gov (United States)

    Karakas, Ahmet Sertac; Bozkurt, Tarik Serhat; Sayin, Baris; Ortes, Faruk

    2017-07-01

    In passenger and freight traffic on the roads, which has the largest share of the hot mix asphalt (HMA) prepared asphalt concrete pavement is one of the most preferred type of flexible superstructure. During the service life of the road, they must provide the performance which is expected to show. HMA must be high performance mix design, comfortable, safe and resistance to degradation. In addition, it becomes a critical need to use various additives materials for roads to be able to serve long-term against environmental conditions such as traffic and climate due to the fact that the way of raw materials is limited. Styrene Butadiene Styrene (SBS) polymers are widely used among additives. In this study, the numerical analysis of SBS modified HMA designed asphalt concrete coatings prepared with different thicknesses with SBS modified HMA is performed. After that, stress and deformation values of the three pavement models are compared and evaluated.

  18. Microorganism Removal in Permeable Pavement Parking Lots ...

    Science.gov (United States)

    Three types of permeable pavements (pervious concrete, permeable interlocking concrete pavers, and porous asphalt) were monitored at the Edison Environmental Center in Edison, New Jersey for indicator organisms such as fecal coliform, enterococci, and E. coli. Results showed that porous asphalt had much lower concentration in monitored infiltrate compared to pervious concrete and permeable interlocking concrete pavers. Concentrations of monitored organisms in infiltrate from porous asphalt were consistently below the bathing water quality standard. Fecal coliform and enterococci exceeded bathing water quality standards more than 72% and 34% of the time for permeable interlocking concrete pavers and pervious concrete, respectively. Purpose is to evaluate the performance of permeable pavement in removing indicator organisms from infiltrating stormwater runoff.

  19. Applications of observational techniques in pavement engineering

    CSIR Research Space (South Africa)

    Steyn, WJVDM

    2007-05-01

    Full Text Available used to obtain these images. Higher resolution images are available through the Agricultural Research Council (ARC) AGIS (Agricultural Geo-Referenced Information System) site. This site provides detailed information on soil, terrain, geology, climate... pavement to be either under- or over-estimated. A further aspect that requires attention during the process of obtaining the images for observational analysis is to ensure that all images are clearly identifiable through a system that would lead...

  20. The Indiana Local Technical Assistance Program Roller Compacted Concrete Pavement Manual for Local Government Agencies

    OpenAIRE

    Shin, Kyung Joon; Carboneau, Neal

    2010-01-01

    Interest in the use of Roller Compacted Concrete (RCC) pavement (RCCP) for local roads and streets has increased. The Indiana Local Technical Assistance Program (LTAP), which is a part of the Purdue University School of Civil Engineering, has developed this document to assist local agencies with the implementation of roller compacted concrete as a paving material. This manual is intended for those interested in planning, designing and constructing RCCP for local roads and streets. It provides...

  1. Mechanistic service life prediction of rigid pavement joint sealant : a new laboratory testing technique

    OpenAIRE

    Abo-Qudais, Saad A.

    1995-01-01

    A new method to evaluate the performance of sealants used in rigid pavement joints was developed. A special fixture, attached to a servo-hydraulic testing machine, was designed to transfer applied cyclic shear deflection to a sealant sandwiched between two 51 x 51 x 51 mm portland cement concrete (PCC) cubes at a constant horizontal deflection. The new testing method simulates field conditions where shear deflection is caused by vehicular loading, while horizontal deflection is...

  2. [Correction of cronic liver failure by transplantation of liver cells suspension and cell-engineering designs (experimental investigation)].

    Science.gov (United States)

    Got'e, S V; Shagidulin, M Iu; Onishchenko, N A; Krasheninnikov, M E; Il'inskiĭ, I M; Mozheĭko, N P; Liundup, A V; Volkova, E A; Petrakov, K I; Avramov, P V; Perova, N V; Sevast'ianov, V I

    2013-01-01

    On an experimental model of chronic fibrotic liver damage (male rats Wistar (n-60), damage of CCl4, the duration of the experiment 90 days) it was studied the effectiveness of cell therapy for the correction of chronic liver failure. These rats were divided into 3 experimental groups: in the Ist-group (control, n=10) isotonic saline (650 mkl.) was injected; in the IInd-group (n=20) suspension of liver cells was applicated in a dose 8 - l0 x 10(6) cells; in the IIIrd-group (n=30) suspension of liver cells and bone marrow cells (mesenchymal stromal cells) in ratio 5:1 were used as cell associates on microparticles intjectable heterogeneous biopolymer hydrogel "SpheroGEL" (cell-engineering design) in common dose 8 - l0 x 10(6) It was ascertained that in the 2nd and in the 3rd groups the accelerated normalization of disturbed liver functional indices (ALT, AST, ALP) took place - to 30 days, but in the control group only to 90 days. The reliable differences in rats ofnormalization offunctional indices were absent between the IInd and the IIIrd groups. But in 90 days by using special histological dyeing it was found out that defibrotic processes in liver tissue were more expressed in the IIIrd group in comparison with the IIIrd group. Received results were consequence of prolonged vital activity of cells (liver cells and mesenchymal stromal bone marrow cells) into cell-engineering designs, which were transplanted in the IIIrd group. The obtained effect can be explained by that the developed cell-engineering designs provide adequate conditions for prolonged vital activity of the transplanted cells.

  3. Pavement cells and the topology puzzle.

    Science.gov (United States)

    Carter, Ross; Sánchez-Corrales, Yara E; Hartley, Matthew; Grieneisen, Verônica A; Marée, Athanasius F M

    2017-12-01

    D'Arcy Thompson emphasised the importance of surface tension as a potential driving force in establishing cell shape and topology within tissues. Leaf epidermal pavement cells grow into jigsaw-piece shapes, highly deviating from such classical forms. We investigate the topology of developing Arabidopsis leaves composed solely of pavement cells. Image analysis of around 50,000 cells reveals a clear and unique topological signature, deviating from previously studied epidermal tissues. This topological distribution is established early during leaf development, already before the typical pavement cell shapes emerge, with topological homeostasis maintained throughout growth and unaltered between division and maturation zones. Simulating graph models, we identify a heuristic cellular division rule that reproduces the observed topology. Our parsimonious model predicts how and when cells effectively place their division plane with respect to their neighbours. We verify the predicted dynamics through in vivo tracking of 800 mitotic events, and conclude that the distinct topology is not a direct consequence of the jigsaw piece-like shape of the cells, but rather owes itself to a strongly life history-driven process, with limited impact from cell-surface mechanics. © 2017. Published by The Company of Biologists Ltd.

  4. Microtexture diagnostics of asphalt pavement surfaces

    Science.gov (United States)

    Florková, Zuzana; Pepucha, L.'ubomír

    2017-09-01

    The microtexture of asphalt pavement surface is an essential parameter from the traffic safety point of view and it closely relates to a geometrical, petrological and physical properties of aggregate particle used in asphalt pavement. Microtexture has a significant influence for assurance basic friction values between tire and pavement in relation to a skid resistance properties. Therefore, the microtexture detecting methods are necessary. The British pendulum tester measurements have been carried out on selected sections of roads with different asphalt surfaces. Individual grains of aggregates were taken from the surface of each section from the sliding path and also from the core sample after the extraction. The laboratory profilometry measurements have been practiced on these aggregate samples and subsequently the surface microtexture was investigated based on commonly used texture characteristics and the filtration approach was applied in calculation process. The results have shown the degradation of microtexture values occurs due to polishing of aggregate under loading from traffic in relation to the type of used aggregate. Some correlation between BPN values and texture characteristics was found.

  5. Soil Properties And Pavement Performance In The Nigerian Rainforest

    African Journals Online (AJOL)

    The geotechnical properties of the sub-structure of the Shagamu-Ore-Benin pavement were studied in an attempt to identifying the quality of construction materials and the pavement performance. The sub-structure soil materials were collected from the field and were taken to the laboratory for particle size analysis, Atterberg ...

  6. Estimating the benefits of improved drainage on pavement ...

    African Journals Online (AJOL)

    user

    The drainage quality is an important parameter which affects the performance of highway pavements. In India ... pavement performance and maintenance needs; and (iii) to quantify the benefits in terms of cost due to the improved drainage ...... Jain was the founder Head of Excellence in Transportation Systems (CTRANS),.

  7. Soil Properties And Pavement Performance In The Nigerian ...

    African Journals Online (AJOL)

    The geotechnical properties of the sub-structure of the Shagamu-Ore-Benin pavement were studied in an attempt to identifying the quality of construction materials and the pavement performance. The sub-structure soil materials were collected from the field and were taken to the laboratory for particle size analysis, Atterberg ...

  8. Long-term Metal Performance of Three Permeable Pavements

    Science.gov (United States)

    EPA constructed a 4,000-m2 parking lot surfaced with three permeable pavements (permeable interlocking concrete pavers, pervious concrete, and porous asphalt) on the Edison Environmental Center in Edison, NJ in 2009. Samples from each permeable pavement infiltrate were collected...

  9. Engineering properties of common subgrade soils below pavement ...

    African Journals Online (AJOL)

    This paper reports findings of laboratory testing of common sub-grade soils in pavement structures in Kenya. The materials were collected from different parts of the country. The results are intended to form a database for use by practicing engineers and researchers in the field of pavement engineering. The investigated ...

  10. Innovations in concrete pavements for a sustainable infrastructure

    NARCIS (Netherlands)

    Pradena, M.; Houben, L.J.M.

    2014-01-01

    Concrete pavements (CPs) are durable and they do not need periodic invasive maintenance interventions. Nevertheless, CPs are hardly chosen when only initial costs, instead of life-cycle costs, are considered in the evaluation. Nowadays, there are innovations in Jointed Plain Concrete Pavements

  11. I-81 in-place pavement recycling project.

    Science.gov (United States)

    2014-08-01

    During the 2011 construction season, the Virginia Department of Transportation (VDOT) completed an in-place pavement : recycling project to rehabilitate a section of pavement on I-81 near Staunton, Virginia. The project consisted of a 3.66-mile : sec...

  12. Initial investigation into development of accelerated pavement evaluation (APE) vehicle

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2002-08-01

    Full Text Available . This is the option of using the HVS to proof-test a newly constructed or in-service pavement or even to only evaluate the pavement response qualitatively over a very short period. The problem addressed in this report is investigate the opportunity to develop a method...

  13. Effects of street tree shade on asphalt concrete pavement performance

    Science.gov (United States)

    E.G. McPherson; J. Muchnick

    2005-01-01

    Forty-eight street segments were paired into 24 high-and low-shade pairs in Modesto, California, U.S. Field data were collected to calculate a Pavement Condition Index (PCI) and Tree Shade Index (TSI) for each segment. Statistical analyses found that greater PCI was associated with greater TSI, indicating that tree shade was partially responsible for reduced pavement...

  14. A systems BIOlogy Study to TAilored Treatment in Chronic Heart Failure: rationale, design, and baseline characteristics of BIOSTAT-CHF

    NARCIS (Netherlands)

    Voors, Adriaan A.; Anker, Stefan D.; Cleland, John G.; Dickstein, Kenneth; Filippatos, Gerasimos; van der Harst, Pim; Hillege, Hans L.; Lang, Chim C.; ter Maaten, Jozine M.; Ng, Leong; Ponikowski, Piotr; Samani, Nilesh J.; van Veldhuisen, Dirk J.; Zannad, Faiz; Zwinderman, Aeilko H.; Metra, Marco

    2016-01-01

    Despite major improvements in pharmacological and device treatments, heart failure remains a syndrome with high morbidity and mortality, poor quality of life, and high health-care costs. Given the extensive heterogeneity among patients with heart failure, substantial differences in the response to

  15. A systems BIOlogy Study to TAilored Treatment in Chronic Heart Failure : rationale, design, and baseline characteristics of BIOSTAT-CHF

    NARCIS (Netherlands)

    Voors, Adriaan A.; Anker, Stefan D.; Cleland, John G.; Dickstein, Kenneth; Filippatos, Gerasimos; van der Harst, Pim; Hillege, Hans L.; Lang, Chim C.; ter Maaten, Jozine M.; Ng, Leong; Ponikowski, Piotr; Samani, Nilesh J.; van Veldhuisen, Dirk J.; Zannad, Faiz; Zwinderman, Aeilko H.; Metra, Marco

    AimsDespite major improvements in pharmacological and device treatments, heart failure remains a syndrome with high morbidity and mortality, poor quality of life, and high health-care costs. Given the extensive heterogeneity among patients with heart failure, substantial differences in the response

  16. Effect of Friction Model and Tire Maneuvering on Tire-Pavement Contact Stress

    Directory of Open Access Journals (Sweden)

    Haichao Zhou

    2015-01-01

    Full Text Available This paper aims to simulate the effects of different friction models on tire braking. A truck radial tire (295/80R22.5 was modeled and the model was validated with tire deflection. An exponential decay friction model that considers the effect of sliding velocity on friction coefficients was adopted for analyzing braking performance. The result shows that the exponential decay friction model used for evaluating braking ability meets design requirements of antilock braking system (ABS. The tire-pavement contact stress characteristics at various driving conditions (static, free rolling, braking, camber, and cornering were analyzed. It is found that the change of driving conditions has direct influence on tire-pavement contact stress distribution. The results provide the guidance for tire braking performance evaluation.

  17. ePave: A Self-Powered Wireless Sensor for Smart and Autonomous Pavement.

    Science.gov (United States)

    Xiao, Jian; Zou, Xiang; Xu, Wenyao

    2017-09-26

    "Smart Pavement" is an emerging infrastructure for various on-road applications in transportation and road engineering. However, existing road monitoring solutions demand a certain periodic maintenance effort due to battery life limits in the sensor systems. To this end, we present an end-to-end self-powered wireless sensor-ePave-to facilitate smart and autonomous pavements. The ePave system includes a self-power module, an ultra-low-power sensor system, a wireless transmission module and a built-in power management module. First, we performed an empirical study to characterize the piezoelectric module in order to optimize energy-harvesting efficiency. Second, we developed an integrated sensor system with the optimized energy harvester. An adaptive power knob is designated to adjust the power consumption according to energy budgeting. Finally, we intensively evaluated the ePave system in real-world applications to examine the system's performance and explore the trade-off.

  18. Effects of Aggregate Gradation on the Physical Properties of Semiflexible Pavement

    Directory of Open Access Journals (Sweden)

    Nadiah Md. Husain

    2014-01-01

    Full Text Available Semiflexible pavement (SFP, a composite pavement, is formed by filling into a very open porous asphalt skeleton a specifically designed water consistency fluid mortar with a very high early and 28-day strength. The amalgamation of both components will produce a SFP where it will replace the conventional wearing course. The main goal of this investigation is to study the effect of various aggregate gradations towards producing SFP. These include determining the optimum binder, volumetric properties, and durability and strength of each aggregate gradation. The final results were statistically analyzed and two factor variance analyses (ANOVA were performed to check on the significance at certain confidence limits. The results confirmed that different aggregate gradations significantly affect the properties mentioned.

  19. Rationale and design of the Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure (AVOID-HF) trial.

    Science.gov (United States)

    Costanzo, Maria Rosa; Negoianu, Daniel; Fonarow, Gregg C; Jaski, Brian E; Bart, Bradley A; Heywood, J Thomas; Nabut, Jose L; Schollmeyer, Michael P

    2015-09-01

    In patients hospitalized with acutely decompensated heart failure, unresolved signs and symptoms of fluid overload have been consistently associated with poor outcomes. Regardless of dosing and type of administration, intravenous loop diuretics have not reduced heart failure events or mortality in patients with acutely decompensated heart failure. The results of trials comparing intravenous loop diuretics to mechanical fluid removal by isolated venovenous ultrafiltration have yielded conflicting results. Studies evaluating early decongestive strategies have shown that ultrafiltration removed more fluid and was associated with fewer heart failure-related rehospitalization than intravenous loop diuretics. In contrast, when used in the setting of worsening renal function, ultrafiltration was associated with poorer renal outcomes and no reduction in heart failure events. The AVOID-HF trial seeks to determine if an early strategy of ultrafiltration in patients with acutely decompensated heart failure is associated with fewer heart failure events at 90 days compared with a strategy based on intravenous loop diuretics. Study subjects from 40 highly experienced institutions are randomized to either early ultrafiltration or intravenous loop diuretics. In both treatment arms, fluid removal therapies are adjusted according to the patients' hemodynamic condition and renal function. The study was unilaterally terminated by the sponsor in the absence of futility and safety concerns after the enrollment of 221 subjects, or 27% of the originally planned sample size of 810 patients. The AVOID-HF trial's principal aim is to compare the safety and efficacy of ultrafiltration vs that of intravenous loop diuretics in patients hospitalized with acutely decompensated heart failure. Because stepped treatment approaches are applied in both ultrafiltration and intravenous loop diuretics groups and the primary end point is time to first heart failure event within 90 days, it is hoped that

  20. Photocatalytic pavement blocks. Air purification by pavement blocks. Final results of the research at BRRC

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The use of materials can influence to a large extent the environmental impact of traffic and of road infrastructure. Especially in urban areas, where the risk on smog formation during hot summer days is high, the use of photocatalytic pavement blocks can reduce the air pollution significantly. A project on environmental friendly concrete pavement blocks is conducted at the Belgian Road Research Centre. The use of photocatalytic material in the surface of pavement blocks to obtain air purifying materials is investigated. In contact with light, TiO2 as photocatalyst, is able to reduce the NO and NO2 content in the air, caused by the exhaust of traffic. The efficiency is tested on pavement blocks, but the technique can as well be applied on other road elements (e.g. noise reducing walls, linear elements) or as a coating on new materials or existing structures. At the previous TRA conference in Gotenborgh, Sweden, the principle of photocatalysis was presented. In this paper, emphasis will be put on the final results of the 4-year project obtained in laboratory as well as on site at the Leien of Antwerp (10,000 m{sup 2}). The results indicate a durable efficiency towards NOx reduction, which is in favour for the diminishing of the risk on ozone formation. However, the precise translation from the laboratory towards the site is still in question. The results obtained during the project are discussed in this paper.