WHY THE ACCELERATED MORTAR BAR METHOD ASTM C 1260 IS RELIABLE FOR EVALUATING THE EFFECTIVENESS OF SUPPLEMENTARY CEMENTING MATERIALS IN SUPPRESSING EXPANSION DUE TO ALKALI-SILICA REACTIVITY

The authors use the Accelerated Mortar Bar Method (AMBM) (American Society for Testing and Materials [ASTM] C 1260 or Canadian Standards Association [CSA] A23.2-25A) to successfully evaluate the effectiveness of supplementary cementing materials (SCMs) in suppressing expansion due to alkali-silica reactivity (ASR) in concrete. AMBM gives good results with SCMs and this study attempts to determine why this method is effective. The most beneficial effects of SCMs against ASR are believed to be the alkali decrease in the pore solution while the bars are immersed in 1N NaOH at 80 deg C. Mortar bars made with different SCMs were tested in normal conditions and in pure water and in air at 100 percent relative humidity. The expansion results were compared with the chemistry of the mortar pore solution expressed under high pressure. Results indicate that in the presence of an SCM, the alkali decrease in the pore solution is the most critical mechanism involved in the AMBM. In addition, the alkali equilibrium between the pore solution and the NaOH immersion solution is not achieved in the presence of an SCM at the end of the testing period of 14 days.

• Availability:
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• Corporate Authors:

  American Society for Testing and Materials (ASTM)

  100 Barr Harbor Drive, P.O. Box C700
  West Conshohocken, PA  United States  19428-2957
• Authors:
  • Berube, M-A
  • Duchesne, J
  • Chouinard, D
• Conference:
  • Symposium on Determination of the Chemical and Mineral Admixture Content of Hardened Concrete
  • Location: Montreal, Quebec, CANADA
  • Date: 1994-6-20 to 1994-6-20
• Publication Date: 1995-6

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 26-34
• Serial:
  • Cement, Concrete and Aggregates
  • Volume: 17
  • Issue Number: 1
  • Publisher: American Society for Testing and Materials (ASTM)
  • ISSN: 0149-6123
  • Serial URL: http://journalsip.astm.org/JOURNALS/CEMENT/cca_home.html

Subject/Index Terms

• TRT Terms: Accelerated tests; Alkali aggregate reactions; Bonding; Cement; Evaluation; Expansion; Fly ash; Materials; Mortar; Silica fume
• Uncontrolled Terms: Supplementary cementing materials
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00715285
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 1 1996 12:00AM