NCHRP Report最新文献

{"title":"Comparing the Volumetric and Mechanical Properties of Laboratory and Field Specimens of Asphalt Concrete","authors":"L. Mohammad, M. Elseifi, S. Cooper, C. Hughes, J. Button, E. Dukatz","doi":"10.17226/23475","DOIUrl":"https://doi.org/10.17226/23475","url":null,"abstract":"This reports document research that was performed to (1) determine causes of variability and tolerances for volumetric and mechanical properties of dense-graded asphalt mixtures measured within and among the three specimen types; and (2) propose a practice for state departments of transportation to incorporate these results in specifications and criteria for quality assurance, mix design verification or validation, and structural design and forensic studies. The research was conducted in two phases. In Phase I, datasets of laboratory and field test data were collected and pooled in a meta-analysis in an attempt to determine levels of variability in asphalt mixtures and the factors causing variability among and between the three specimen types. Despite the inclusion of 25 extensive datasets representing roughly 8,000 individual mixtures in the meta-analysis, the results of the analysis were inconclusive. Phase II was then undertaken—a program testing specimens from paving projects across the United States to quantify the effects of process-based factors on the variability of volumetric and mechanical properties of the specimen types. The key outcome of the research is a proposed practice for evaluating the cause and magnitude of variability within and among the three specimen types. In addition, tolerances of volumetric and conversion factors between the three specimen types of mechanical properties evaluated are proposed based on the average difference between specimen comparisons for the mixtures evaluated in Phase II. Agencies may use these proposed values to evaluate and adjust their current tolerances.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129771093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of Guidelines for Evaluating the Moisture Susceptibility of WMA Technologies","authors":"A. Martin, E. Arambula, Fan Yin, Eun Sug Park","doi":"10.17226/23452","DOIUrl":"https://doi.org/10.17226/23452","url":null,"abstract":"National Cooperative Highway Research Project (NCHRP) 9-49, which was completed in 2013, developed guidelines for warm mix asphalt (WMA) mix design and quality control to identify and minimize any possibility of moisture susceptibility. The objective of the current project, NCHRP Project 9-49B, was to validate and revise, if necessary, the thresholds in the guidelines developed in NCHRP Project 9-49. The research was based on a survey of the state departments of transportation (DOTs) and paving contractors to identify WMA mixtures with available field performance, mix design, and quality assurance data, including wet indirect tensile (IDT) strengths and tensile strength ratios, wet resilient moduli and ratios, and Hamburg wheel tracking parameters. The survey identified 89 field projects with either IDT or Hamburg wheel tracking results. These results were analyzed to validate the thresholds established for the tests in NCHRP Project 9-49. The key practical outcome of the research is a flowchart presented in this report for conditioning and testing WMA laboratory specimens in the mix design process that incorporates the validated thresholds.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123864549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Framework for a Pavement-Maintenance Database System","authors":"George White, Steven Velozo, D. Peshkin, Prashant V. Ram","doi":"10.17226/24665","DOIUrl":"https://doi.org/10.17226/24665","url":null,"abstract":"","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124112377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-Term Laboratory Conditioning of Asphalt Mixtures","authors":"D. Newcomb, A. Martin, Fan Yin, E. Arambula, Eun Sug Park, A. Chowdhury, Ray Brown, Carolina Rodezno, N. Tran, Erdem Coleri, David J. Jones, J. Harvey, J. Signore","doi":"10.17226/22077","DOIUrl":"https://doi.org/10.17226/22077","url":null,"abstract":"This report develops procedures and associated criteria for laboratory conditioning of asphalt mixtures to simulate short-term aging. The report presents proposed changes to the American Association of State Highway and Transportation Officials (AASHTO) R 30, Mixture Conditioning of Hot-Mix Asphalt (HMA), and a proposed AASHTO practice for conducting plant aging studies. The report will be of immediate interest to materials engineers in state highway agencies and the construction industry with responsibility for design and production of hot and warm mix asphalt.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127035940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guide for the Preservation of Highway Tunnel Systems","authors":"C. Allen, Martha Averso, C. Hargraves, S. Mcneil","doi":"10.17226/21903","DOIUrl":"https://doi.org/10.17226/21903","url":null,"abstract":"Tunnel preservation includes actions or strategies that prevent, delay, or reduce deterioration of tunnel systems (preventive maintenance); restore the function of existing tunnels (repair or rehabilitation); and keep tunnels in good condition and extend their useful life. This report presents a guide for the preservation of highway tunnel systems to (1) assist tunnel owners in making informed decisions using an asset management process to support their prioritization of highway tunnel preservation actions and (2) provide executives with credible, evidence-based information on capital funding needs for tunnel improvements as part of their overall transportation system funding, as well as a means for communicating those needs. This guide provides a process for prioritizing needs, using an overall measure of effectiveness that is calculated using a risk-based urgency score, and developing capital funding and staffing programs to accomplish tunnel preservation goals. It also serves as a training tool for new personnel.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":" 22","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120832668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guidebook on Alternative Quality Management Systems for Highway Construction","authors":"K. Molenaar, D. Gransberg, David N. Sillars","doi":"10.17226/22128","DOIUrl":"https://doi.org/10.17226/22128","url":null,"abstract":"This guidebook provides recommendations and tools to assist in developing quality management systems (QMSs) and assistance in creating a better definition of quality management in the context of alternative project delivery. The roles of owners and contractors in QMSs are changing, leading to variation in the roles and responsibilities of quality assurance organization (QAO). These range from the agency-dominated system of quality management associated with the traditional design-bid-build (DBB) method to design-build (DB)/public-private partnership (PPP) agreements where the responsibility for quality management is shared to varying degrees between the contractor and owner. The chapters in this report address the business case for alternative QMSs, QAOs, QAO selection, and useful tools for an alternative QMS. This report will be valuable to highway construction engineers by facilitating the development of QMSs for evolving alternative project delivery methods.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126143650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Properties of Foamed Asphalt for Warm Mix Asphalt Applications","authors":"D. Newcomb, E. Arambula, Fan Yin, Jun Zhang, A. Bhasin, Wei Li, Z. Arega","doi":"10.17226/22145","DOIUrl":"https://doi.org/10.17226/22145","url":null,"abstract":"This report presents proposed AASHTO standard test methods for measuring performance-related properties of foamed asphalts and designing foamed asphalt mixes with satisfactory aggregate coating and workability. The objectives of this project were to determine key properties of foamed asphalt binders that significantly influence the performance of asphalt mixtures and develop laboratory protocols for foaming of asphalt binders and laboratory mixing procedures. The production and performance-related properties of foamed asphalt were investigated through a series of laboratory and field experiments. A key finding of the research is that the foaming characteristics of an asphalt binder are primarily affected by its source (i.e., its crude oil slate), the production date for a given refinery and crude oil slate, and polymer modification. A laser-based method was developed to measure parameters associated with the expansion and collapse of foamed asphalt. A digital photographic approach was developed to characterize the size, distribution, and surface area of bubbles formed during production of foamed asphalt. Methods were also identified for determining a coatability index for foamed asphalt and the workability of mixes produced with foamed asphalt. A foamed asphalt mixture design procedure was developed to identify the optimum water content for coating and workability. Finally, the utility and effectiveness of these various methods were verified through their application to foamed asphalt binder and mix produced in full-scale asphalt mix plants. This report fully documents the research. Four appendixes are included: Influence of Binder Properties on Binder Foam Expansion; Draft Commentary on Guidelines Proposed for Revising Appendix to AASHTO R 35; AASHTO Style Standards; and Field Foaming Data Acquisition Form.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129599961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Test Methods for Specific Gravity and Absorption of Coarse and Fine Aggregate","authors":"N. Tran, R. West, H. Azari","doi":"10.17226/22147","DOIUrl":"https://doi.org/10.17226/22147","url":null,"abstract":"Design and production of paving asphalt and portland cement concrete (PCC) mixtures rely on accurate, precise measurement of aggregate specific gravity and absorption. Aggregate specific gravities are needed to calculate the voids in mineral aggregate (VMA) and effective binder content of asphalt mixtures, which are key volumetric properties used in mix design and acceptance testing. For PCC, aggregate absorption is used to adjust water/ cement or water/cementitious material ratios which affect the workability of PCC and are a good indicator of PCC’s resistance to freezing and thawing and PCC’s durability. The current AASHTO standard test methods for aggregate specific gravity and absorption, namely, T 84, Specific Gravity and Absorption of Fine Aggregate, and T 85, Specific Gravity and Absorption of Coarse Aggregate, share several shortcomings in terms of subjectivity of the measurements, time requirements for conditioning and testing, and precision. The objective of NCHRP Project 4-35 was to develop test methods for determining the specific gravity and absorption of coarse and fine aggregates with improved accuracy, precision, ease of use, and time required for conditioning and testing, compared to the current AASHTO T 84 and T 85 methods. The key outcome of the research is the finding that AASHTO T 85 with several proposed changes, AASHTO T 84 (modified to remove and separately test P200 material), and ASTM D7172 (Standard Test Method for Determining the Relative Density (Specific Gravity) and Absorption of Fine Aggregates Using Infrared) provide a good balance of accuracy and precision compared to the other methods evaluated, including the current AASHTO T 85 and T 84. This finding was developed through a critical literature review on the basis of which an initial set of ten test methods was selected for evaluation in a series of five laboratory experiments and a ruggedness study. This report fully documents the research and includes the following two appendixes: Revised AASHTO T 85 and Revised AASHTO T 84 In addition, seven appendixes are available to download from the NCHRP Project 4-35 web page at http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=1614. These appendixes summarize the literature review, testing results of the experiments, and results of a ruggedness study.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130206179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guidebook for Designing and Managing Rights-of-Way for Carbon Sequestration and Biomass Generation","authors":"J. Proudfoot, David Ponder, D. Tindall, D. Wysocki","doi":"10.17226/22154","DOIUrl":"https://doi.org/10.17226/22154","url":null,"abstract":"This report provides a Guidebook and Toolkit that describes the state of the practice of using highway rights-of-way (ROWs) vegetation for carbon sequestration and biomass generation for use as feedstock for biopower and biofuel production. This Guidebook merges the knowledge of market conditions and regulations for environmental commodities that are energy- and/or greenhouse-gas based, regulations governing the highway ROWs for commercial or revenue purposes, the best practices of highway vegetation management and agronomic practices for raising feedstock crops for carbon sequestration, biopower, and biofuels. The Feasibility Toolkit, available on CD-ROM (CRP-CD-165), may assist users with modeling a proposed project’s financial viability that the user can modify to develop a customized analysis.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128534211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proposed Practice for Alternative Bidding of Highway Drainage Systems","authors":"M. Maher, G. Hebeler, Andrew R. Fuggle, Colby Caywood, K. Avery, Joseph A VanKerkhove, I. Moore","doi":"10.17226/22157","DOIUrl":"https://doi.org/10.17226/22157","url":null,"abstract":"This research investigated the use of a performance-based process for selection of drainage pipe systems. Such a selection process is based on satisfying performance criteria for the drainage system while considering the full range of suitable pipe materials. This approach has the potential to foster competition among various pipe types judged to be of satisfactory quality and equally acceptable on the basis of engineering and cost analyses. Giving contractors the ability to choose from among alternative drainage pipe systems during the bidding process on the basis of performance and cost can help agencies promote competition that will lower agency costs while achieving satisfactory performance. The objective of NCHRP Project 10-86 was to develop a proposed practice suitable for adoption by AASHTO to guide owner-agencies and industry in implementing a performance-based process for contractor selection and delivery of drainage pipe systems on highway construction projects. The key product of the research is the proposed practice presented in Appendix A of the report. The practice applies rational, performance-based criteria to the selection, installation and post-construction acceptance of highway drainage pipe systems. It specifically addresses the selection of pipe solutions by evaluating the hydraulic capacity, structural capacity, and durability of pipe systems in distinct stages. Since durability is predicted in terms of estimated service life, the practice emphasizes proper characterization of the site conditions and comprehensive post-installation inspection to confirm construction quality. The practice was tested and refined through comparisons in nine states to standard agency procedures for pipe specification and was shown to satisfactorily consider the wide variety of factors required to successfully bid alternative pipe systems. This report fully documents the research and includes the following two appendixes: Appendix A: AASHTO Recommended Practice for Alternative Bidding of Highway Drainage System and Appendix C: Summary of Durability Evaluation Methods and Software Applications.","PeriodicalId":350472,"journal":{"name":"NCHRP Report","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124211563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}