Research Reports
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Abstract
This report presents a brief historical overview of the development of expansive (shrinkage compensating) concrete. Three Utah Department of Transportation projects using expansive concrete are discussed as to the performance of the expansive concrete. On-site inspections were performed on three projects: (1) a bent repair at I-80 and Highland Drive, (2) a bridge deck rehabilitation at Starvation Reservoir, and (3) two overpasses where Utah 201 merges with I-80 near Black Rock. The inspecting engineers' diaries and contract documents were also reviewed to determine why there is a variance in the performance of the expansive concretes in these three projects. It appears that the poor performance of the expansive concrete in the Black Rock overpasses is due to insufficient water for the formation of the ettringite being provided to the concrete during curing. Placement of the same concrete in hot weather may have also contributed to the cracking in these bridge decks.
The recommendation is made that the Utah Department of Transportation should have a new specification written that addresses directly the use of expansive concrete. The research that would be necessary to write this new specification is also discussed. The report is organized in the following chapters: (1) Introduction; (2) Overview; (3) Performance Comparison; (4) Conclusions; and (5) Recommendations.