Development of Shrinkage Limits and Testing Protocols for ODOT High Performance Concrete

Oregon Department of Transportation (ODOT) has observed varying degrees of cracking in their concrete structures. Cracking of high performance reinforced concrete structures, in particular bridge decks, is of paramount concern to ODOT. Cracking at early ages (especially within the first year after placement) results in additional costs and a significant maintenance burden to ODOT. The causes behind cracking in high performance concrete (HPC) are well known and documented in the existing literature. However, appropriate shrinkage limits and standard laboratory/field tests that allow proper criteria to ensure crack-free or highly cracking-resistant high performance concrete are not clearly established either in the technical literature or in specifications. The purpose of this research was to provide shrinkage threshold limits for specifications and to provide a robust test procedure that allows easy determination of compliance with specified threshold limits. It has been shown that the “restrained ring” tests are the most comprehensive accelerated laboratory tests to accurately identify cracking potential. In addition, acceptable correlation between the ring test and the field test has been observed and documented. However, a simplified yet robust test procedure is in demand from materials suppliers and Departments of Transportation. Analysis of data obtained from this research project showed that the ratio of free shrinkage to shrinkage capacity (theoretical strain related to tensile strength and modulus of elasticity), referred to as a cracking potential indicator (CPI), was a promising assessment of cracking resistant performance. In this way, only the free shrinkage test (ASTM C157) and basic mechanical properties (ASTM C39, C469 and C496) are required to assess cracking risk of candidate high performance concrete mixture designs. This research investigation showed that a CPI less than 3.0 indicated low cracking risk when correlated to standard restrained ring tests. For ODOT HPC concrete bridge deck mixtures, a limit of 450 microstrain for free shrinkage at 28 day from initiation of drying is recommended to achieve satisfactory cracking resistance. Correlation to field experience is also recommended if these recommended thresholds/limits are adopted by ODOT.

• Record URL:
  • http://www.oregon.gov/ODOT/Programs/ResearchDocuments/SPR728_ShrinkageLimits-Final.pdf
• 
• Corporate Authors:

  Oregon Department of Transportation

  Research Section
  555 13th Street NE
  Salem, OR  United States  97301

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ideker, Jason H
  • Fu, Tengfei
  • Deboodt, Tyler
• Publication Date: 2013-12

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 87p

Subject/Index Terms

• TRT Terms: Bridge decks; Cracking; High performance concrete; Literature reviews; Shrinkage; Shrinkage limit; Test procedures
• Geographic Terms: Oregon
• Subject Areas: Bridges and other structures; Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01505675
• Record Type: Publication
• Report/Paper Numbers: FHWA-OR-RD-14-09, SPR 728
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Jan 27 2014 11:27AM