AGGREGATE TOUGHNESS / ABRASION RESISTANCE AND DURABILITY TESTS RELATED TO ASPHALT CONCRETE PERFORMANCE IN PAVEMENTS By
i DISCLAIMER The contents of this report reflect the views of the authors who are solely responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views and policies of the National Center for Asphalt Technology of Auburn University. This report does not constitute a standard, specification, or regulation. ii ABSTRACT Numerous tests have been developed to empirically characterize aggregate without, necessarily, a strong relationship with the performance of the final products incorporating these aggregates. This seems to be particularly true for aggregate " toughness and abrasion resistance " and " durability and soundness. " The purpose of this research was to identify and evaluate toughness/abrasion resistance and durability/soundness tests for characterizing aggregate used in asphalt concrete and to determine those test methods that best correlate with field performance. Based on a review of literature and specifications, laboratory tests for characterizing aggregate toughness/abrasion resistance and durability/soundness were selected. Sixteen aggregate sources with poor to good performance histories were identified for evaluation with the selected suite of tests. Performance histories of pavements containing these aggregates in asphalt concrete layers were established through personal contacts with state transportation agencies and performance evaluation questionnaires. Aggregate properties from laboratory tests were correlated with field performance. The Micro-Deval and magnesium sulfate soundness tests provide the best correlations with field performance of asphalt concrete, and are recommended for characterizing aggregate toughness/abrasion resistance and durability/soundness.
Guide for Pavement Friction
This report documents the research performed under NCHRP Project 1-43. It describes the work activities undertaken in the study and presents the results of those activities toward the development of the Guide for Pavement Friction. The information provided in this report serves as the basis for many of the guidelines and recommendations contained in the Guide. The information will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements. Using information collected through detailed literature reviews and surveys/interviews with state highway agencies, this report discusses a variety of aspects regarding pavement friction. It describes and illustrates the importance of friction in highway safety, as well as the principles of friction, as defined by micro-texture and macro-texture. It identifies the factors affecting friction and examines the ways that friction can be measured (equipment and procedures) and expressed (reporting indices). Most importantly, it presents valuable information on (a) the management of friction on existing highway pavements and (b) the design of new highway surfaces with adequate friction. This information focuses on techniques for monitoring friction and crashes and determining the need for remedial action, as well as identifying combinations of aggregate (micro-texture) and mix types/surface texturing methods (macro-texture) that satisfy friction design requirements. The report includes various conclusions and recommendations based on the results of the study, and it features five appendixes containing supplemental information on friction.
A Phenomenological Study of the Wind Band Experience: Stories of Band
A PHENOMENOLOGICAL STUDY OF THE WIND BAND EXPERIENCE: