STP829: California Study of Asphalt Concrete Density Measurement—Nuclear Versus Core Density

    Alexander, ML
    Associate materials and research engineer and senior materials and research engineer, California Department of Transportation, Sacramento, CA

    Doty, RN
    Associate materials and research engineer and senior materials and research engineer, California Department of Transportation, Sacramento, CA

    Pages: 13    Published: Jan 1984


    Abstract

    The lack of a fast, reliable method for accurately determining in-situ density has been the major obstacle in the California Department of Transportation's (Caltrans) effort to develop an end-result compaction requirement for asphalt concrete pavement. Although the nuclear gage provides a rapid method of determining inplace densities, the results have not proven consistent with the densities determined by the generally accepted water displacement method of testing core specimens. This paper discusses factors contributing to these inconsistencies. It is concluded that the water displacement method is incorrectly described as a measure of bulk density and is not measuring the same properties as the nuclear method. It is also concluded that the Caltrans procedure for calibrating backscatter nuclear gages is introducing inconsistencies into the nuclear density determinations.

    Several procedures for measuring the density of thin layers (less than 50 mm) of asphalt concrete have been examined. These procedures are described and their weaknesses discussed.

    Keywords:

    asphalt concrete, bituminous concrete, flexible pavement, compacting, core testing, density measurement, density (mass/volume), bulk density, nuclear gages


    Paper ID: STP32502S

    Committee/Subcommittee: D04.40

    DOI: 10.1520/STP32502S


    CrossRef ASTM International is a member of CrossRef.