Nemzetközi szemle: Január
Nagy terhelésre alkalmas burkolatok tervezése és építése
Design & Construction of Heavy-Duty Pavements
Szerző(k): H.L. Von Quintus, C.S. Hughes
National Asphalt Pavement Association USA
Terjedelem: 74 oldal
Heavy duty mixes are needed in any pavement structure subjected to severe loading conditions as evidenced by the number and weight of heavy loads, heavy static loads, and/or high tire pressures. As pavements meeting these conditions increase, heavy-duty mixes designed to withstand these loads are being used more frequently. Integrating the pavement structural and mixture designs is essential to provide a longlasting, durable pavement under severe traffic conditions. This publication provides a state-of-the-practice of the material selection, mixture design, structural design, and construction of asphalt mixtures and pavements used under heavy truck traffic or specialized loading conditions, including discussing the use of large-stone mixtures, polymers, and other additives commonly used to provide higher strengths for heavy-duty asphalt mixtures. Because the aggregate skeleton must carry much of the load, it is important that a good quality crushed aggregate is used and that the gradation meets the appropriate requirements. The gradation requirements typically require large nominal maximum size aggregate. Although segregation of the large stone can be a problem, using good production and construction practices can minimize this. Three principal problems that may arise when using large maximum size aggregate are segregation, aggregate fracture, and a slight increase in equipment wear. These problem areas are discussed with an emphasis on the causes of, and steps that can be taken to overcome, segregation.
Teljesítmény mátrixok fejlesztése innovatív csomópont típusok értékeléséhez
Development of Performance Matrices for Evaluating Innovative Intersections and Interchanges
Szerző(k): M. Zlatkovic
University of Wyoming USA
Terjedelem: 80 oldal
Innovative intersections and interchanges have proliferated in the State of Utah over the past several years. Continuous flow intersections and diverging diamond interchanges seem to offer improved traffic performance and safety due to their innovative designs. However, there are no clearly defined guidelines or methodologies for monitoring and measuring their performance. Yet, they have a broad impact on operations, safety, access, transit, land use, economic development, and pedestrian and non-motorized traffic. Due to these numerous and overlapping variables, there is a need to develop a standard methodology to further evaluate innovative designs with regards to different performance measures. The goal of this research is to develop a matrix of performance measures, which can be applied in practice to effectively evaluate innovative designs in terms of operations, safety, access, and multimodal accommodations. The study develops and tests an Excel-based tool for evaluation and comparison of different conventional and innovative designs. The tool is based on the existing methodologies and those currently being developed, and they provide analyses of these designs for different performance measures, such as operational, safety, transit and non-motorized user performance, access, and user costs. It can be used for planning, designing, and monitoring performance of innovative designs.
Kis forgalmú utak aszfalt burkolatai műszaki szükségleteinek összegzése
A Synthesis of Technical Needs of Asphalt Pavements for Local Roads
Szerző(k): F. Leiva-Villacorta, R.C. West, E.R. Brown
National Center for Asphalt Technology USA
Terjedelem: 37 oldal
Low-volume roads (LVRs) connect farms, mines, and businesses to smaller communities and residential areas. They are an essential link in the movement of raw materials and products from rural communities to the more populated areas of society. Under this investigation, researchers conducted a search for literature relevant to pavement design and asphalt mixture design of LVRs. This investigation was complemented with a web-based survey submitted to state agencies and industry in an attempt to answer some questions that many practitioners may have related to the state-of-the-practice of LVR design.
Kis sebességű és városi utak burkolat egyenetlenségének mérése, jellemzése és bemutatása
Measuring, Characterizing, and Reporting Pavement Roughness of Low-Speed and Urban Roads
Szerző(k): S.M. Karamihas, M.E. Gilbert, M.A. Barnes, R.W. Perera
The University of Michigan, GIS Linking the Layers, SME, USA
Terjedelem: 167 oldal
This report reviews the practices for roughness measurement and the unique features of urban and low-speed roadways, and it evaluates the use of existing inertial profilers for such measurements. The report also proposes revisions to AASHTO standard specifications and practices addressing inertial profiler certification and operations. The information contained in the report will be of immediate interest to state materials and pavement engineers and others involved in the different aspects of pavement condition monitoring and evaluation.
Az építési minőségbiztosítás kulcs elemeinek alkalmazása
Key Elements of Construction Quality Assurance for Implementation
Szerző(k): Transportation Research Board USA
Terjedelem: 50 oldal
Lectern Session 604 on Quality Assurance: There’s Value in the Basics, was held at the 2018 Annual Meeting of the Transportation Research Board (TRB). In this session, four speakers with a range of perspectives—the Federal Highway Administration (FHWA), state transportation agencies, and a contractor—presented on key elements and best practices for implementation of an effective quality assurance program. It is important to take the time to understand the strengths and weaknesses of specifications and test procedures when writing them. In addition, it is key to consider the quality assurance specifications and procedures from not just the agency’s perspective. Whenever possible, it is best practice to obtain all relevant data, including the originally measured weights. Doing so would afford an excellent opportunity to perform a data forensic investigation. And finally, when limited with options, creatively plot the data in alternate formats and inspect for trends that may not be revealed by conventional analyses.
Repedés szigetelési technológiák hatékonyságának költség-haszon elemzése
Cost/Benefit Analysis of the Effectiveness of Crack Sealing Techniques
Szerző(k): M.Barman, J. Munch, U.M. Arepalli
University of Minnesota Duluth USA
Terjedelem: 139 oldal
Crack sealing is an important preventive treatment in the pavement preservation program. To achieve a cost-effective crack seal, it is important to select a proper crack sealing method. While Minnesota usually seals cracks in asphalt pavements, there is no clear consensus on the most appropriate crack sealing method for a specific job. This study focused on developing a guideline so that a cost-effective crack sealing method could be chosen based on pavement type, functional condition, pavement age, and traffic volume etc. This study includes a literature review, online survey, field performance data collection and analysis, and development of a guideline. The effectiveness of the crack seals was determined using a benefit-cost analysis. Two decision trees were developed for choosing the most appropriate crack sealing method. The first, which can be used in MnDOT’s pavement management system, needs information such as crack severity, pavement type (new vs overlay), pavement analysis period and design life, traffic level, and crack seal occurrence number. The second decision tree, which is a simplified version of the first and can be used by the preventive maintenance crews and requires less information: crack severity, traffic level, and crack sealing occurrence number.
Útmutató repülőtéri burkolatok állapot adatainak gyűjtésére, alkalmazására és karbantartására
Guidelines for Collecting, Applying, and Maintaining Pavement Condition Data at Airports
Szerző(k): D. Peshkin, P.F. Dzwilewski, K.M. Potvin, K. Gauthier, M. Wade, E. Risner, R. Robinson, C. Snyder, M. Cardwell, K. Feighan
Applied Pavement Technology, Inc., Woolpert, Inc., USA, PMS Ltd. Ireland
Terjedelem: 123 oldal
ACRP Research Report 203: Guidelines for Collecting, Applying, and Maintaining Pavement Condition Data at Airports provides guidance for airports on best practices in collecting and using airfield pavement condition data. As part of the pavement management process the data are used to determine the Pavement Condition Index (PCI), which in turn is used to inform and improve operations, maintenance, and capital improvement programs. The availability of guidance to help airports determine the best approaches to collect, apply, and maintain pavement condition data has not kept pace with rapid changes in the associated technology, and this report was developed to address the need for guidance on the strategies available for pavement condition data collection, use, and storage. Decision tools (decision trees and matrices) are used to present appropriate strategies. Many airports approach this topic differently, and with new technologies deployed, there will continue to be a broad range of practices. The guidelines presented will help those involved in airport pavement condition data to sort through associated decisions related to those practices.