Evaluation of Shrinkage Cracking Potential of Concrete Used in Bridge Decks in Florida

The main objectives of this research are (1) to develop an effective and convenient laboratory set-up and procedure for evaluating concrete mixtures for their resistance to shrinkage cracking in service, (2) to evaluate the different concrete mixtures that have various different admixtures added for reducing the shrinkage in the concrete, and (3) to make recommendations for concrete mix designs for improved resistance to shrinkage cracking in service. The constrained long specimen apparatus, which was previously developed for the Florida Department of Transportation (FDOT) by the University of Florida for evaluation of resistance to shrinkage cracking of concrete, was further refined and evaluated. The major refinements included (1) using a load cell to measure the induced force in the constrained long specimen, (2) using an embedment strain gage to measure the strain of the long specimen, (3) using an automatic data acquisition system to collect the load and strain data continuously, (4) using a water-resistant and low-friction Teflon sheet as a base plate to minimize the friction between the concrete specimen and its supporting base, and (5) a modification to the test procedure to correct for the specimen contraction. The results of the testing program indicated that the use of a shrinkage-reducing admixture was effective in reducing the free shrinkage strains and shrinkage-induced stresses of all the concrete mixtures tested, while the compressive strength, splitting tensile strength and elastic modulus of the concrete were not significantly affected. The addition of fly ash as a mineral admixture was found to be effective in reducing the free shrinkage strain and shrinkage-induced stresses of all the concrete.

Language

  • English

Media Info

  • Media Type: Print
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 141p

Subject/Index Terms

Filing Info

  • Accession Number: 01014837
  • Record Type: Publication
  • Report/Paper Numbers: UF Project No. 4910-4504-797-12
  • Contract Numbers: BC 354 - RPWO #26
  • Files: TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Dec 19 2005 9:31AM