COMPARATIVE FIELD AND LABORATORY INVESTIGATIONS FOR EVALUATING POTENTIAL ALKALI-REACTIVITY OF AGGREGATES

Over the years, the Accelerated Mortar Bar Test (AMBT) and the Concrete Prism Test (CPT) have become critical tools in supporting engineering decisions regarding the use of concrete aggregates and the risk of deleterious expansion due to alkali-aggregate reactivity. Data obtained in the author's laboratory and published in the literature have shown that, despite some inconsistencies, the AMBT is a good screening test for evaluating potential alkali-reactivity of aggregates; however, it is good practice and often necessary to verify AMBT data using the CPT. The expansion levels obtained in the AMBT do not necessarily give a good indication of the reactivity level or ultimate amount of expansion to be generated by an aggregate in field practice; however, aggregates inducing high accelerated mortar bar expansions, i.e. possibly > 0.35%, often generate high concrete prism expansion. The CPT uses a single mixture design and accelerated test conditions; however, useful engineering information could be obtained from testing aggregates from concretes of various alkali contents. Higher expansion or more extensive concrete deterioration due to AAR can be observed in field structures compared to the ultimate expansion level or the reactivity level suggested by the CPT. Alkali leaching from test prisms stored at 38C and R.H. > 95%, as well as the deleterious effect of wetting/drying and/or freezing/thawing cycles in the field possibly explain, at least partially, these differences.

• Supplemental Notes:
  • Full conference proceedings available on CD-ROM.
• Corporate Authors:

  University of Texas, Austin

  International Center for Aggregates Research, 3208 Red River
  Austin, TX  United States  78705-2650

  Texas A&M University, College Station

  Faculty Exchange Box H
  College Station, TX  United States  77843
• Authors:
  • Fournier, Benoit
• Conference:
  • International Center for Aggregates Research 9th Annual Symposium: Aggregates - Concrete, Bases and Fines
  • Location: Austin, Texas
  • Date: 2001-4-22 to 2001-4-25
• Publication Date: 2001

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 15p

Subject/Index Terms

• TRT Terms: Alkali aggregate reactions; Concrete aggregates; Deterioration; Drying; Expansion; Field tests; Freeze thaw tests; Laboratory tests; Leaching; Reactive aggregates; Test procedures; Wetting
• Uncontrolled Terms: Accelerated mortar bar test; Concrete prism tests
• Subject Areas: Geotechnology; Highways; I36: Aggregates;

Filing Info

• Accession Number: 00983562
• Record Type: Publication
• Report/Paper Numbers: Final Draft
• Files: TRIS
• Created Date: Dec 23 2004 12:00AM