CLOSING IN ON ASR POPOUTS

Found most often on hard-troweled aggregate surfaces in the Northern Great Plains, these small popouts are unusual in that they often appear within a few hours after concrete is finished. Research has been performed to determine the cause of these popouts and to seek methods to prevent them. After petrographic examinations of these popouts confirmed the presence of alkali-silica reactivity (ASR), research was set out to find the factors that most contribute to popout formation. This paper reviews a laboratory study that was undertaken to investigate several variables, including cement content, finishing technique, air entrainment, and curing procedure. Some of the recommended procedures that offer the best protection against the formation of popouts include: wet curing, as early as possible, particularly in the hot summer months; protecting fresh concrete from drying before final finishing; and avoiding hard troweling if possible.

• Corporate Authors:

  Portland Cement Association

  5420 Old Orchard Road
  Skokie, IL  United States  60077
• Publication Date: 2002-7

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 2-4
• Serial:
  • Concrete Technology Today
  • Volume: 23
  • Issue Number: 2
  • Publisher: Portland Cement Association

Subject/Index Terms

• TRT Terms: Air entrained concrete; Alkali silica reactions; Cement content; Concrete; Curing agents; Surface course (Pavements); Surface course irregularities
• Uncontrolled Terms: Popouts
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00962947
• Record Type: Publication
• Report/Paper Numbers: CT022
• Files: TRIS
• Created Date: Sep 4 2003 12:00AM