FACTORS INFLUENCING FLOW AND STRENGTH OF STANDARD MORTARS AND REAPPRAISAL OF THE POZZOLANIC ACTIVITY INDEX TEST

Modified ASTM C 311 Pozzolanic Activity Index (PAI) Tests with five fly ashes and two portland cements were done to compare results with those of standard tests. When sand contents (at constant water and cement contents) were varied strengths of 38 deg C cured mortars decreased (-30 to -50 kPa/gram of sand added) for different cement/fly ash blends. When water contents (at constant sand contents) were varied, strengths varied (-125 to +190 kPa/mL), strengths tending to increase because of paste volume fractions; the slopes are related by a factor of 0.60 +/- 0.04. Accelerated curing at 38 deg C for tests at 28 days usually yields higher PAI values than relative strengths after curing at 23 deg C for 91 days. Multiple linear regression equations using both kinds of test data are solved at specified flow and strength values to determine proportions and mortar volume yields. This more general performance test ranks fly ashes by mortar volume yield at equal flow and strength, and is suggested as a candidate to replace the present PAI test.

  • Corporate Authors:

    Portland Cement Association

    5420 Old Orchard Road
    Skokie, IL  United States  60077
  • Authors:
    • Helmuth, R
  • Publication Date: 1994

Language

  • English

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 36 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00675387
  • Record Type: Publication
  • Report/Paper Numbers: RP323, PCA R&D Serial No. 1859
  • Files: TRIS
  • Created Date: Mar 27 1995 12:00AM