The characteristics of fresh concrete affecting consolidation (workability, consistency and aptitude to compaction) are examined in the first part of the article. It is shown that the water content is one of the most important of known factors affecting the consistency of concrete. A study is also made of the influence of time on consistency. Details are given of methods of studying the consolidation process and the behaviour of fresh concrete subjected to vibration (sedimentation curve, measurement of bulk density, etc.). The second part deals with the direct and indirect effects of consolidation by vibration on concrete characteristics. It is shown that the density of coarse aggregates and consistency are two important factors affecting the tendency to segregation during vibration. The increase in concrete strength resulting from the use of dry mixtures subjected to vibration is clearly shown by the relation existing between the strength and the water/cement ratio and the relation between strength and settlement. The effect of air content, and therefore of the degree of consolidation, on the compressive strength of concrete is studied quantitatively. It is shown, for example, that A 5% increase in the air content reduces compressive strength by one third. The effect of the quantity of air on several other properties of hardened concrete (flexural strength, modulus of elasticity, etc.) is also clearly demonstrated. The study also showed that the stiffness of fresh vibrated concrete determines changes in mix design: for example, it is possible to have a different particle size distribution with coarser aggregates. /TRRL/

  • Corporate Authors:

    Springer Verlag

    175 5th Avenue
    New York, NY  USA  10010
  • Authors:
    • Popovics, S
  • Publication Date: 1972-5-6

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Filing Info

  • Accession Number: 00099605
  • Record Type: Publication
  • Source Agency: Laboratoire Central des Ponts et Chausees (LCPC)
  • Files: ITRD, TRIS
  • Created Date: Nov 18 1975 12:00AM