Date of Award

12-2014

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Eric N. Landis

Second Committee Member

Edwin Nagy

Third Committee Member

Todd S. Rushing

Abstract

Ultra high performance fiber reinforced concrete (UHPFRC) is a reactive powder concrete characterized by its high compressive strength. In spite of its applicability to many modern engineering needs, it is not as well understood as conventional reinforced concrete, particularly in a fracture context. To develop accurate computational models to predict the behavior of UHPFRC, laboratory testing and non-destructive evaluation is valuable.

Fiber pull-out tests were conducted using half-dogbone specimens for single, double, and inclined deformed steel fiber pull-out. Embedment length, fiber separation distance, and inclination angle varied. An analysis of the load-slip data showed a large amount of scatter, which may be real and should be considered in future Cor-Tuf models.

Additionally, UHPFRC beams were tested under static and impact loading and then scanned using x-ray computed tomography. The scans were then examined to correlate visible energy dissipation mechanisms with the external work of load. We found that fiber pull-out was the most dominant mechanism for all load rates and were able to account for most of the energy in most of the hooked-end fiber reinforced specimens. However, there is a lot unaccounted for fiber pull-out in the analysis of the straight fiber reinforced specimens, likely due to the size and quantity of the fibers.

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