Selected In-Track Applications and Performances of Hot-Mix Asphalt Trackbeds

2013 ◽  
Author(s):  
Jerry G. Rose
Keyword(s):  
Impact Load ◽  
The United States ◽  
Factors Affecting ◽  
Support Materials ◽  
Maintenance And Rehabilitation ◽  
A Site ◽  
Engineering Practices ◽  
Long Term Performance ◽  
Term Performance

The use of a layer of asphalt within railway trackbeds has steadily grown since the early 1980s in the United States. Its primary use has been for maintenance and rehabilitation applications in existing tracks, particularly at special trackworks, to improve trackbed performance, and to a lesser extent for new trackbed applications where the projected long-term performance of the asphalt trackbed is anticipated to be economically justified. Normally the asphalt layer is 6 in. (150 mm) thick, placed on a prepared subgrade or granular subballast, and is subsequently topped with a layer of typical ballast. Accepted highway/railway construction practices are adhered to, including adequate preparation and compaction of the support layers. In addition, surface and sub-surface drainage aspects are evaluated on a site-specific basis and improvements are specified based on accepted engineering practices. This application does not deviate significantly from conventional all-granular trackbed designs, except the asphalt layer is substituted for a portion of the thickness of the granular subballast and ballast support materials. Described herein are 1) typical trackbed designs, 2) in-track applications, and 3) long-term performance evaluations for various types of major applications on several U.S. Class I railroads, namely NS, UP, CSX, and BNSF, and a limited number of Shortline railroads. Specifically addressed are rehabilitation applications for special trackworks — tunnel floors/approaches, wheel impact load detectors, bridge approaches, rail-highway crossings, turnouts, rail crossings, and rail crossovers — plus descriptions for a limited number of new double-tracking open-track installations. Brief descriptions are provided for international applications in six countries. Particular detail is given to factors affecting the economic justification for utilizing this technology based on long-term performances and historical evaluations of numerous installations. Details are provided relative to unique conditions and logistics related to the application of the layer of asphalt within the trackbed support for the special trackworks and selected open-track installations. Several specific installations are highlighted.

Advanced Techniques for Establishing Long-Term Performance of Composite Repair Systems

2014 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
The United States ◽  
Operating Conditions ◽  
Repair System ◽  
Composite Repair ◽  
Design Life ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance ◽  
Composite Repairs

Although composite materials are used to repair and reinforce a variety of anomalies in high pressure transmission gas and liquid pipelines, there continues to be widespread debate regarding what constitutes a long-term composite repair. The United States regulations require that composite repairs must be able to permanently restore the serviceability of the repaired pipeline, while in contrast the Canadian regulations take a more prescriptive approach by integrating the ASME PCC-2 and ISO 24817 composite repair standards along with a requirement for establishing a 50-year design life. In this paper the author provides a framework for what should be considered in qualifying a composite repair system for long-term performance by focusing on the critical technical aspects associated with a sound composite repair. The presentation includes a discussion on establishing an appropriate composite design stress using the existing standards, using full-scale testing to ensure that stresses in the repair do not exceed the designated composite design stresses, and guidance for operators in how to properly integrate their pipeline operating conditions to establish a design life. By implementing the recommendations presented in this paper, operators will be equipped with a resource for objectively evaluating the composite repair systems used to repair their pipeline systems.

Updated Review of Stone Matrix Asphalt and Superpave® Projects

2003 ◽  
Vol 1832 (1) ◽  
pp. 217-223 ◽  
Author(s):  
Donald E. Watson
Keyword(s):  
Material Properties ◽  
The United States ◽  
Mix Design ◽  
Stone Matrix Asphalt ◽  
High Traffic Volume ◽  
Long Term Performance ◽  
Term Performance ◽  
Stone Matrix

Stone matrix asphalt (SMA) and Superpave® represent relatively new mix design technologies in the United States. Therefore, a condition survey was conducted of mixes that had been in service for several years to evaluate the long-term performance of SMA and Superpave projects. This study is a follow-up to a 1995 review of SMA projects and a 1998 review of Superpave projects. Both SMA and Superpave are acknowledged to be rut-resistant mixes, and this resistance was shown to be the case during this project review. However, a significant amount of cracking occurred early in the life of some of these mixtures. Overall, the SMA mixtures appeared to be more durable than the Superpave mixtures evaluated. The SMA mixtures have been in place about 2½ years longer than the Superpave mixtures, but the overall condition is about the same. Some of the primary conclusions from the survey are as follows: both SMA and Superpave mixtures were shown to be rut-resistant even when placed on facilities with high traffic volume; much of the observed cracking, especially load cracking, appeared to be more related to problems other than mix design or material properties; and SMA mixtures can be expected to last longer than Superpave mixtures before reaching the same condition level.

Analysis of the Factors Affecting Sustainable Electronic Supply Chains in Healthcare Centers

2018 ◽  
Vol 31 (4) ◽  
pp. 23-43
Author(s):  
Hossein Sayyadi Tooranloo ◽  
Salim Karimi ◽  
Khatereh Vaziri
Keyword(s):  
Supply Chains ◽  
Infrastructure Management ◽  
Interpretive Structural Modeling ◽  
Factors Affecting ◽  
Business Operations ◽  
Long Run ◽  
Healthcare It ◽  
Long Term Performance ◽  
Term Performance

To improve their long-term performance, organizations must maintain their business operations and practices over time. They can do so by engaging in sustainable practices aimed at meeting the interests of the enterprise, and of its suppliers, employees, and customers in the long run. Not surprisingly, the implementation of sustainability practices has expanded in the healthcare industry. Information technology (IT) is a way to promote quality, security, and efficiency in healthcare. IT brings vital information, and so important support to the care point for decision-making. It also allows the assessment of everyday quality turn into as a measured reality. In the present study, the factors affecting the sustainability of electronic supply chains in healthcare centers were identified using library methods and a keyword review of the literature. Then, the relationships between these factors were analyzed using an interpretive- structural modeling approach. The results reveal that infrastructure management and technology management should be considered the most important factors affecting the sustainability of electronic supply chains in healthcare centers.

Doe Progress in Assessing the Long Term Performance of Waste Package Materials

1986 ◽  
Vol 84 ◽  
Author(s):  
A. Berusch ◽  
E. Gause
Keyword(s):  
Site Characterization ◽  
The United States ◽  
High Level Waste ◽  
Design Studies ◽  
Waste Package ◽  
License Application ◽  
High Level ◽  
Long Term Performance ◽  
Term Performance

Summary:Each of the projects has made significant progress toward the eventual operation of a repository for the disposal of high-level radioactive wastes in the United States. Although much has been accomplished, much remains to be done. For example, the Site Characterization Plans for BWIP and NNWSI are nearing completion to be followed by initiation of site characterization activities. The Site Characterization Plan for the selected salt site is scheduled for completion later in 1987. Waste package advanced conceptual design studies are currently scheduled to begin at each project before the end of FY 1987. These efforts will lead to selections of concepts to be detailed in the license application design phase. Compliance with the NRC criteria that require long-term waste package performance will be demonstrated by DOE by performing all of the aforementioned activities. In doing so, the DOE will also be assured that its plan for the safe disposal of high-level waste will be satisfactorily implemented.

Asphalt Trackbed Technology Development: The First 20 Years

2000 ◽  
Vol 1713 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jerry G. Rose ◽  
E. Ray Brown ◽  
Monica L. Osborne
Keyword(s):  
Technology Development ◽  
The United States ◽  
Optimum Moisture Content ◽  
Performance Evaluations ◽  
Track Structure ◽  
Maintenance Costs ◽  
Rail Network ◽  
Long Term Performance ◽  
Term Performance

The evolution of hot-mix asphalt (HMA) trackbed technology is documented as presently practiced in the United States. Criteria used in selecting sites for and the attendant benefits of HMA trackbeds, based on long-term performance evaluations, are discussed. Prevailing practices for selecting ideal HMA mix parameters, trackbed section designs, and application procedures are described in detail. Primary attention is directed at the “underlayment” procedure in which the HMA serves as a premium subballast layer within the track structure to enhance the support, waterproofing, and confinement properties of the subballast. The roadbed or subgrade materials underlying the HMA mats maintain near-optimum moisture content. The HMA appears to undergo little if any weathering or deterioration in the trackbed environment. The resultant benefits are decreased maintenance costs, fewer slow orders, fewer operational interferences, and improved operational efficiency of the rail network overall.

Sustainability Considerations for PCC Pavement Design and Construction

2013 ◽  
Vol 857 ◽  
pp. 147-159
Author(s):  
Liang Liang Chen ◽  
Dan G. Zollinger ◽  
Bo Tian
Keyword(s):  
Field Testing ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Factors Affecting ◽  
Key Issues ◽  
Pavement Structures ◽  
Long Term Performance ◽  
Term Performance ◽  
Relevant Material

This paper addresses key issues regarding important factors affecting the sustainability and long-term performance of Portland cement concrete (PCC) pavement structures. Key distress types and their associated features are discussed in terms of their effect on performance and sustainability in terms of specific pavement components. Relevant material properties are also identified and discussed as to how they are represented in laboratory and field testing. A process to manage inspection resources is described and illustrated with the aid of a sustainability worksheet. This paper does not represent a guide or a standard for design or analysis.

Lessons Learned from the Yucca Mountain and WIPP Projects

2010 ◽  
Vol 73 ◽  
pp. 194-202 ◽  
Author(s):  
Evaristo J. Bonano ◽  
David S. Kessel ◽  
Lori J. Dotson
Keyword(s):  
System Analysis ◽  
The United States ◽  
Yucca Mountain ◽  
Lessons Learned ◽  
Total System ◽  
Waste Isolation Pilot Plant ◽  
License Application ◽  
Long Term Performance ◽  
Term Performance

For more than 30 years Sandia National Laboratories (SNL) has played a key role in the development and implementation of total system analyses of waste management systems in the United States. Two very important applications have been the total system analysis of long term performance that supported (1) the Compliance Certification Application (CCA) for the Waste Isolation Pilot Plant (WIPP) in 1996 and (2) the License Application (LA) for the Yucca Mountain (YM) Repository in 2008.

Evaluation of Factors Affecting Long-Term Performance of Cold In-Place Recycled Pavements in New York State

2011 ◽  
Vol 2227 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Warren H. Chesner ◽  
Christopher W. Stein ◽  
Henry G. Justus ◽  
Edward R. Kearney ◽  
Stephen A. Cross
Keyword(s):  
New York ◽  
New York State ◽  
Factors Affecting ◽  
York State ◽  
Long Term Performance ◽  
Term Performance
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