Strength Characterizations of Different UHPCs

  • Sahith Gali (Iowa State University)
  • Sri Sritharan (Iowa State University)


Ultra-high-performance concrete (UHPC), with its superior mechanical characteristics and durability, provides a potential way for sustainable highway infrastructure in the United States and worldwide. To attain these properties, the presence of fibers plays an integral part in ultra-high-performance concrete (UHPC) mixes. This paper studies the influence of fiber volume on the compressive strength and tensile behavior of UHPC. To investigate these material dependencies, specimens were cast using UHPC from three different suppliers with three fiber volume fractions of 1%, 2%, and 3%. AASHTO T397 test procedure was used to quantify the direct tensile behavior of UHPC. In addition, longer dog-bone specimens than specified in AASHTO 397 were cast to investigate the effects of change in gauge length on tensile behavior. Cubes of 2 in x 2 in x 2 in. and cylinders with dimensions 3 in. (diameter) x 6 in. (length) were tested for compression strength comparisons at four different ages. At 3% fiber volume, the strength ratio of cylinders to cubes was found to be around 1. However, the strengths of cylinders were higher than cube strengths at lower fiber volumes. The strength ratio did not vary with the age of UHPC. Varying fiber volume fractions significantly influenced the tensile strength and post-cracking tensile response of UHPC. A higher volume of fibers resulted in higher tensile strength and a more extensive multi-cracking phase. The crack straining phase was dependent on the UHPC type and did not depend on fiber volume. An increase in gauge length resulted in reduced residual tensile load-carrying capacities.

Keywords: UHPC, AASHTO T 397, direct tensile test, fiber volume, tensile behavior

How to Cite:

Gali, S. & Sritharan, S., (2023) “Strength Characterizations of Different UHPCs”, International Interactive Symposium on Ultra-High Performance Concrete 3(1): 134. doi:

Rights: © 2023 The Author(s). All rights reserved.

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Published on
04 Jun 2023
Peer Reviewed