详情

当前位置：首页> 国外交通科技报告数据库 >详情

原文传递 Aggregate Quality Requirements for Pavements. National Cooperative Highway Research Program (NCHRP) Synthesis 524. A Synthesis of Highway Practice.

题名：	Aggregate Quality Requirements for Pavements. National Cooperative Highway Research Program (NCHRP) Synthesis 524. A Synthesis of Highway Practice.
作者：	Tran, D.; Gransberg, D. D.; Harper, C.; Tutumluer, E.; Moaveni, M.; Qambia, I. I. A.
关键词：	Highways planning, Aggregate quality tests, Recycled concrete aggregate (RCA), Blast Furnace Slag (BFS), Innovative contracting, Synthesis, Requirements, Transportation agencies, National Cooperative Highway Research Program (NCHRP), Federal Highway Administration (FHWA)
摘要：	Aggregates encompass a wide range of materials including quarried rock, sand, and gravel in addition to recycled/artificial/byproduct materials such as reclaimed asphalt pavement (RAP) and recycled concrete aggregate (RCA), steel furnace slag (SFS), blast furnace slag (BFS), and quarry byproducts (QB). Aggregate type and quality are important factors for determining use and placement within different layers of the pavement structure. There are wide variations in what transportation agencies consider suitable aggregates for specific pavement applications. This synthesis gathered information and presents information related to aggregate quality requirements for pavement construction. Both current agency practices as well as state-ofthe- art research findings on sources, locations, standards/provisional testing methods, and ranges for different types of aggregates used in North America are provided. This includes quality assurance methods as well as frequency of sampling and testing established. This synthesis also provides information on how aggregate quality has been documented and linked to both structural and functional pavement performance in the field through agency practices and experience. Environmental concerns such as leaching and potential risk to ground or outfall waters are discussed. Finally, knowledge gaps related to characterizations and classifications of different types of aggregates, including lack of performance-based specifications and implementation of effective aggregate quality assurance programs, are identified. The synthesis survey questionnaire (Appendix A) on aggregate quality requirements for pavements included 34 questions posed to transportation agencies in four categories: (1) aggregate sources and properties; (2) aggregate sampling, quality control, tests, and ranges; (3) procedures for approving aggregate sources; and (4) aggregate-related performance records. Survey questionnaires were sent out to all 50 U.S. Departments of Transportation (DOTs) and 12 Canadian provincial agencies. Appendix B is a list of all U.S. DOTs and Canadian provincial agencies that provided responses. A response rate of 90% was achieved with U.S. DOTs. In total, 45 U.S. DOTs and eight Canadian provincial agencies (Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Prince Edward Island, Saskatchewan, and Yukon) participated in the survey. Twenty-seven U.S. DOTs as well as Ontario and Yukon provided their approved lists of aggregates. A detailed compilation of the comprehensive survey responses provided by participating agencies may be found in Appendix C. In addition, links to agency-approved lists of aggregates/specifications are provided in Appendix D. The appendices are not printed as part of this report but are available for download from the TRB website (www.trb.org) by searching for NCHRP Synthesis 524. Based on the reviews of the survey responses and follow-up communications with agency contacts, differences exist among transportation agencies when it comes to the methods for approving aggregate materials and quality assurance programs. Alaska, Illinois, Indiana, Ohio, Ontario, and Texas were found to have some of the most comprehensive aggregate
报告类型：	科技报告