| 1st Place: Modulus of Elasticity and Mechanical Behavior of Ultra-High-Performance Concrete |
| Author: Cadets Mainor E. Bojorquez, David T. Carlson, and Alexander J. Vanhout, United States Military Academy, West Point, New York |
| Faculty Advisors: Lieutenant Colonel Karl F. Meyer and Dr. Christopher Conley |
| Abstract: The purpose of this study was to determine the modulus of elasticity (MOE) of ultra-high-performance concretes (UHPC). This included identifying any trends and behaviors that were different between UHPC and standard strength concrete. This research consisted of performing compression strength and modulus of elasticity tests on 2 in. cubes, and cylinders including sizes 2 x 4, 3 x 6, 4 x 8, and 6 x 12 in. (50 x 101, 76 x 152, 101 x 203, and 152 x 304 mm). The cylinders were cast with Cor-Tuf, developed by the Army Engineer Research and Development Center (ERDC), and Ductal, a proprietary material produced by The Lafarge Company. Both forms of UHPC were tested with and without steel fibers. The most significant finding was that the MOE ceased to increase with increasing strength in the UHPC cylinders, and instead hit a ceiling and leveled off, showing even a slight decreasing trend. This finding suggested that at compressive strengths encountered with UHPC, the MOE characteristics may begin to behave more like that of steel, with a single common value, and less like that of standard concrete. It was also found that as specimen size increased, MOE increased slightly. Further, increased unit weight correlated with increased MOE; following this trend, samples with steel fibers tended to be denser and had higher MOE values. The reasons for the differences in behavior between UHPC and normal concretes include careful selection of particle sizes, pozzolanic reactions coupled with a special curing regimen, and improved microcracking behavior. It was found that the most consistent MOE results came from 4 x 8 cylinders; 3 x 6 cylinders produced slightly less consistent results, and 6 x 12 cylinders showed broad scatter. |
| 2nd Place: Toughness and Toughness Index Evaluation of Steel Fiber Reinforced Concrete for Repairing Works in Hydraulic Structures |
| Author: Prabhanjan B. Wagh College of Engineering Pune Maharashtra, India |
| Faculty Advisor: Ishwar P. Sonar |
| 3rd Place: Cast-in-Place Low Density Cellular Concrete |
| Author: Alex Bertheau Arizona State University Tempe, Arizona |
| Faculty Advisor: Luke M. Snell |