ADMIXTURES FOR PAVEMENT-QUALITY CONCRETE

This article discusses some problems in pavement-quality concrete, and argues that the use of admixtures in concrete should be a standard requirement in the UK. The main areas of concern for high-strength, air-entrained, pavement-quality concrete are: (1) maintaining consistent and stable air content; (2) achieving required strengths; (3) problems of using them in hot weather; and (4) for barriers, minimising blowholes and improving the surface finish. Modern air-entraining agents improve the resistance of concrete to frost and de-icing salts, but decrease strength, roughly by 5% for every 1% of entrained air. Aggregate type is a prime factor in achieving strength, especially if crushed rock is used. Admixtures can resolve most of the problems in cement-rich mixes. The combined use of a powerful superplasticiser and air-entraining agent can normally give 28-day strengths above 53N/sq mm. Many countries, especially Scandinavian countries, already have specifications for concretes with excellent freeze-thaw resistance. British Standard BS 5075 specifies admixtures suitable for hot weather applications. Superplasticisers often help to improve surface finish. Modern admixture technology, combined with microsilica, could well be the best way to produce high-strength, durable pavement-quality concrete.

  • Availability:
  • Corporate Authors:

    THE CONCRETE SOCIETY

    112 WINDSOR ROAD
    SLOUGH, BERKSHIRE  United Kingdom  SL1 2JA
  • Authors:
    • FARMER, R
  • Publication Date: 1996

Language

  • English

Media Info

  • Pagination: p. 30-2
  • Serial:
    • CONCRETE
    • Volume: 30
    • Issue Number: 1
    • Publisher: THE CONCRETE SOCIETY
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00723181
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jul 26 1996 12:00AM