Water-powder mixtures at the onset of flowing

M. Hunger, H.J.H. Brouwers

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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    Abstract

    The knowledge of water demands of the manifold concrete ingredients is of vital interest for the design of concrete mixes. Physical properties like workability or strength and durability in hardened state are controlled by the total water content. Water demand is defined as the volumetric ratio of water to solid material at a certain state, which is defined by the selected test method. Given that powders provide the b far highest percentage of specific surface area in a concrete mixture, their water demand is of special interest. In literature diverse methods for the determination of powders’ water demands can be found. However, it appears that the spread-flow test, sometimes referred to as mini-slump flow test, has achieved general acceptance in concrete technology. In this research the spread-flow test has been analyzed in more detail. In this way new measures are derived which contribute to a deeper understanding of wet granular mixtures at the onset of flowing. The deformation coefficient which will be derived by the spread-flow test was confirmed to correlate with the product of Blaine surface and intrinsic density of the individual powders when the mixture is flowing only under its own weight. Similarly, correlations with equal accuracy have been found with a computed specific surface based on measured particle size distributions instead of the Blaine surface. Using flow experiments it was possible to derive an overall factor for assessing the non-spherical shape of the powder particles. A good correlation of this computation algorithm was derived compared to the standard Blaine method. Finally, a constant water layer thickness around the powder particles was derived for all powders at the onset of flowing. This implies the possibility to predict flow behavior of mortar and concrete mixtures only based on the knowledge of their granular characteristics.
    Original languageEnglish
    Title of host publicationInternational Conference of Construction and Building Technology, ICCBT 2008 16-20 June 2008, Kuala Lumpur, Malaysia
    EditorsH. Al-Mattarneh, K.N. Mustapha, M.F. Nuruddin
    Place of PublicationKajang, Malaysia
    PublisherUniversiti Tenaga Nasional
    Pages411-422
    ISBN (Print)978-967-305-152-6
    Publication statusPublished - 16 Jun 2008
    EventInternational Conference on Construction and Building Technology, ICCBT 2008 - Kuala Lumpur, Malaysia
    Duration: 16 Jun 200820 Jun 2008

    Conference

    ConferenceInternational Conference on Construction and Building Technology, ICCBT 2008
    Abbreviated titleICCBT
    CountryMalaysia
    CityKuala Lumpur
    Period16/06/0820/06/08

    Keywords

    • METIS-249736
    • Water demand
    • Spread-flow test
    • Constant Water layers
    • Specific surface area
    • Blaine

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