AIR ENTRAINMENT IN MORTARS AND CONCRETE: THE EFFECT OF SUPERPLASTICIZER/SALT COMBINATIONS

The use of salt-saturated solutions in mixing super plasticized mortars and concretes will sometimes lead to the entrainment of large quantities of air (in excess of 20 per cent, often as high as 50 per cent). The author describes a test to quantify the potential of various superplasticizers to entrain air when used in salt-containing mortars and concrete. A solid form of a sulphonated naphthalene formaldehyde condensate (SNFC) was mixed with saturated brine solution, with and without defoaming agents, and the level of foaming was measured. The test was repeated using 20 per cent active liquid sulphonated melamine formaldehyde condensate (SMFC) in place of SNFC. In the case of SNFC, reaction with the salt produced a large amount of relatively stable foam, only partially controlled by defoamers. In the case of SMFC there is less foaming and it can be effectively controlled with a defoamer. The test described is a simple one which allows quick determination of the potential for foaming. (TRRL)

  • Availability:
  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  United States  10523
  • Authors:
    • Grutzeck, M
  • Publication Date: 1984-3

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Filing Info

  • Accession Number: 00392438
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 29 1985 12:00AM