Volume 21, Issue 2 (December 1999)

    Delayed Ettringite Formation (DEF) in Structural Lightweight Aggregate Concrete: Effect of Curing Temperature, Moisture, and Silica Fume Content

    CODEN: CCAOAD

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    Abstract

    The results confirm that the self-desiccation of normal density (ND) high strength concrete may prevent delayed ettringite formation (DEF). However, when using lightweight aggregate (LWA), the initial water content of the LWA grains seems to be sufficient to give some DEF. The results also confirm that the critical temperature, provided that the moisture content is sufficiently high, is in the range of 65 to 70°C for ND concrete with Norwegian cements. The critical temperature for LWA concrete seems to be somewhat higher; above 70°C. The LWA expansion due to DEF seems to be somewhat lower than the expansion of ND concrete, provided they have the same binder and paste quality. The volume increase coincides with an extensive compressive strength reduction. The reported results confirm that addition of silica fume (5%) in combination with the investigated cements, seems to prevent or eliminate the DEF.


    Author Information:

    Rønne, M
    Research engineer and senior research engineer, SINTEF Civil and Environmental Engineering, Cement and Concrete, Trondheim,

    Hammer, TA
    Research engineer and senior research engineer, SINTEF Civil and Environmental Engineering, Cement and Concrete, Trondheim,


    Stock #: CCA10434J

    ISSN: 0149-6123

    DOI: 10.1520/CCA10434J

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    Author
    Title Delayed Ettringite Formation (DEF) in Structural Lightweight Aggregate Concrete: Effect of Curing Temperature, Moisture, and Silica Fume Content
    Symposium , 0000-00-00
    Committee C09