Scanning Electron Microscope Characterization of the Surfaces of ASTM C 109 Standard Ottawa Sand Grains

    Volume 1, Issue 1 (January 1979)

    ISSN: 0149-6123

    CODEN: CCAOAD

    Page Count: 4


    Barnes, BD
    Assistant professor of civil engineering, North Carolina State University, Raleigh, N.C.

    Diamond, S
    Professors of engineering materials, School of Civil Engineering, Purdue University, W. Lafayette, Ind.

    Dolch, WL
    Professors of engineering materials, School of Civil Engineering, Purdue University, W. Lafayette, Ind.

    Abstract

    Surface microstructural features of Ottawa sand prescribed for mortar strength tests of portland cements in ASTM C 109 have been examined by scanning electron microscopy. The observed features include large areas of rounded grain surface that appear etched or frosted at low magnification and are seen to consist of sharp hills and valleys on a scale of a few micrometres; some areas of smooth planar surfaces representing cleavage planes; a number of large dish-shaped concavities thought to arise through conchoidal fractures associated with violent grain-to-grain contact; and incised lines separating some of the frosted surface into roughly polygonal blocks about 50 μm across. The frosted areas probably represent the results of repeated local dissolution and reprecipitation of silica.


    Paper ID: CCA10169J

    DOI: 10.1520/CCA10169J

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    Author
    Title Scanning Electron Microscope Characterization of the Surfaces of ASTM C 109 Standard Ottawa Sand Grains
    Symposium , 0000-00-00
    Committee C01