ADMIXTURE FOR CONTROLLING BLEED IN CEMENT GROUT USED IN POST-TENSIONING

The bleed characteristics of neat cement grout are well known. With usual mixing procedures and grout admixtures it can be expected that water separation will occur due to sedimentation of the suspension of cement and admixture in water. This is particularly exaggerated with strand-type tendons. To control this characteristic and the general pumping problems grout blockages with dewatering, a grout admixture has been developed which can control the bleed as desired. The basic research in developing this admixture used short strand tendons to determine the different water retentive characteristic of admixtures. However, based on these tests, it was found that the vertical scale factor of pressure is important. Thus, a pressure filter test was also sued to determine the water retentive characteristic of various grouts. Based on this research, a grout admixture was developed with the property of high water retentivity such that for instance no water loss will occur in the grout when the pressure is maintained at 100 atmospheres over 10 min. For shorter durations, water retentivity is fully maintained for even higher pressures. /Author/

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  • Corporate Authors:

    Prestressed Concrete Institute

    20 North Wacker Drive
    Chicago, IL  United States  60606
  • Authors:
    • Schupack, M
  • Publication Date: 1974-11

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Filing Info

  • Accession Number: 00265340
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 29 1975 12:00AM