Test Methods for Characterizing Aggregate Shape, Texture, and Angularity

The properties of coarse and fine aggregates used in hot-mix asphalt and hydraulic cement concrete and unbound base and subbase layers are very important to the performance of the pavement system in which they are used. Particle shape, texture, and angularity are among the aggregate properties that have significant effects on performance. These properties vary widely with the type and source of aggregates and processing techniques. However, current aggregate specifications do not address in a direct manner the measurement of these properties, thus leading to inconsistent interpretation and use of test results. Several methods for measuring aggregate shape, texture, and angularity characteristics were developed in recent years, and others are being developed as part of ongoing research efforts. However, an evaluation of these methods--with respect to their practicality, labor requirements, ease of use, cost, versatility, field applicability, use in multiple ratio shape analysis, and other factors--has not been performed. Without this information, a rational recommendation for incorporating such test methods in aggregate specifications can not be made. Research is needed to evaluate potential test methods and identify or develop suitable test methods for measuring relevant properties in central and field laboratories, and to develop recommendations to help improve specifications for aggregates used in highway pavements. The objective of this research is to identify or develop, for use in central and field laboratories, suitable test methods for measuring shape, texture, and angularity characteristics of aggregates used in hot-mix asphalt and hydraulic cement concrete and unbound base and subbase layers of highway pavements. The research should focus on the characteristics of coarse aggregates, but may also consider the characteristics of fine aggregates. The research will make use of the information developed under NCHRP Project 4-30.

Language

  • English

Project

  • Status: Completed
  • Funding: $450000.00
  • Contract Numbers:

    Project 4-30A

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Hanna, Amir

  • Performing Organizations:

    Texas A&M Research Foundation, College Station

    Texas A&M University
    College Station, TX  United States  77843
  • Principal Investigators:

    Masad, Eyad

  • Start Date: 20030828
  • Expected Completion Date: 0
  • Actual Completion Date: 20050531
  • Source Data: RiP Project 10154

Subject/Index Terms

Filing Info

  • Accession Number: 01460738
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 4-30A
  • Files: RiP, USDOT
  • Created Date: Jan 3 2013 1:31PM