ADMIXTURES

The article reviews the uses of various types of admixtures designed to overcome a particular constraint affecting concrete quality. Plasticising admixtures allow concrete to be placed in high ambient temperatures and low humidity by delaying setting times and maintaining workability. Compressive strengths attained are 20-25% higher compared with plain concrete placed under the same conditions. Besides plasticisers, liquifiers, retarders and accelerators, the use of air-entraining agents can also be an aid in producing good quality concreting. The advantages of including minute air bubbles include improved freeze-thaw stress resistance, reduced permeability, less segregation and increased strength of lean and lightweight mixes. The importance of correct curing particularly in high temperature conditions is also discussed. Such techniques include covering surfaces with moisture retaining materials, immersing precast units in lagoons or spraying with water, and, covering concrete surfaces with a vapour-proof membrane. /TRRL/

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  • Corporate Authors:

    Morgan-Grampian (Professional Press) Limited

    Morgan-Grampian House, Calderwood Street
    London SE18 6QH,   England 
  • Publication Date: 1978-9

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00189197
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 12 1979 12:00AM