Although the fundamental importance of pore structure of aggregates is recognised it is noted in the paper that successful linking of this with properties of concrete has not yet been possible. The authors accept that absorption of water by aggregates is important per se; it also allows indirect assessment of pore structure by characterising the pores, not in terms of sizes (based on assumptions about their shapes) but in terms of accessibility to water under simple immersion, low pressure (0.2 n/sq mm) and partial vacuum (630 mm Hg). Results are given for immersion periods from 20 seconds up to 2 years, for the first, and up to 90 days for the other two methods. The simple BS 812 technique used with normal weight aggregates is shown to be acceptable with the crushed limestone and with the five lightweight aggregates used. It is shown that the disturbance during mixing of "saturated" high-porosity aggregates can lead to emission of significant volumes of water. The difference in behaviour between the sintered fly ash aggregate and the others is thought to be related to its more uniform and accessible pore structure arising from the fly ash particles and their sintering. It is concluded that useful information on aggregate pore characteristics is available from studies of simple water absorption tests. (Author/TRRL)

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    Scientific and Technical Press Limited

    Chilberton House, Doods Road
    Reigate, Surrey,   England 
  • Authors:
    • Lydon, F D
    • Al-Mahfoudh, H H
  • Publication Date: 1989-3

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Filing Info

  • Accession Number: 00492800
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1990 12:00AM