Ultra-High Performance Concrete (UHPC) is a new generation of cement based construction materials which features superior mechanical and material properties. Its compressive and flexural strengths are higher than 29 ksi and 7 ksi respectively. UHPC is reinforced with steel fibers of 0.5 to 1.0 in long and 0.008 in thick. Its constituent materials are extremely fine graded – smaller than 0.024 in. The improvement in micro-structural level results in very low permeability in UHPC which leads to enhancement in durability and resistance against all kinds of corrosion.
For further utilization of UHPC in the industry, special knowledge of its behavior is needed. The minimum dimensions of structural members allowed by building code requirements are set based on conventional concrete. Since UHPC's constituent materials are more expensive than those of conventional concrete, utilization of UHPC with current minimum dimensions increases the cost drastically. Thus, development of new specifications and new applications is needed.
A prior research at Ohio University has shown that the bond performance between UHPC and prestressing strands are satisfactory. This research addresses the flexural redistribution issue in UHPC. Four beams, with dimensions of approximately 50 in x 4 in x 4in were tested. The tests were set up such that two concentrated loads were applied at about the center of two spans supported at three points. The amount of moment redistribution from middle support into the spans were found to be 14 percent which is lower than 20 percent in conventional concrete allowed by ACI 318 – 08 building code requirements.