This article describes some practical problems that arise from the building code requirement for structural concrete that states that the strength level of a given class of concrete is satisfactory if two requirements are met. These requirements are (1) that every arithmetic average of any three consecutive strength tests equals or exceeds the specified compressive strength; and (2) no individual strength test falls below the compressive strength by more than 500 psi (4Mpa) when the compressive strength is 5000 psi (35 Mpa) or less, or by more than 0.10 compressive strength when the compressive strength is more than 5000 psi. If the individual strength test does not meet the second criterion, an investigation of low-strength test results must be performed. Problems often arise in determining the significance of low test results. In some cases situations arise in the field that make it difficult to calculate the average of three consecutive strength tests. Other concerns are raised with the need for core tests, strength results from 56-day cylinders or results from a different lab.


  • English

Media Info

  • Pagination: p. 48-50
  • Serial:
    • Concrete International
    • Volume: 25
    • Issue Number: 8
    • Publisher: American Concrete Institute (ACI)
    • ISSN: 0162-4075

Subject/Index Terms

Filing Info

  • Accession Number: 00961788
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 4 2003 12:00AM