Early-age shrinkage cracking has been observed in many concrete bridge decks in Washington State and elsewhere around the U.S. The cracking increases the effects of freeze-thaw damage, spalling, and corrosion of steel reinforcement, thus resulting in premature deterioration and structural deficiency of the bridges. In this study, the main causes of the early-age cracking in the decks are identified, and concrete mix designs as a strategy to prevent or minimize the shrinkage cracking are evaluated. Different sources (eastern and western Washington) and sizes of aggregates are considered, and the effects of paste content, cementitious materials (cement, fly ash, silica fume, slag), and shrinkage reducing admixture (SRA) are evaluated. A series of fresh, mechanical and shrinkage property tests were performed for each concrete mix. The outcomes of this study identify optimum concrete mix designs as appropriate mitigation strategies to reduce or eliminate early-age shrinkage cracking and thus help minimize shrinkage cracking in the concrete bridge decks, potentially leading to longer service life.
May 11, 2010
Pizhong Qiao, David I. McLean, Jianmin Zhuang.
Washington State Transportation Center (TRAC)
- # of Pages: 91p., 1.47 MB (PDF)
- Subject: Shrinkage, Bridge decks, Concrete bridges, Cracking, Admixtures, Evaluation and assessment, Properties of materials, Materials tests, Expansive concrete.
- Keywords: Bridges, decks, shrinkage cracking, concrete mixes, aggregates, cementitious materials, shrinkage reducing admixture, SRA, free shrinkage, restrained shrinkage.
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This abstract was last modified January 22, 2013