Effects of Synthetic Fibers and Different Levels of Partial Cement Replacement on Mechanical Properties of UHPFRC

Abstract

This paper presents the results of an experimental study conducted to investigate the effects of polypropylene fibers and synthetic macrofibers (barchip) with different partial cement replacements on the mechanical properties of ultra-high-performance fiber-reinforced concrete (UHPFRC). For this study, 21 mix designs were prepared to contain three different fibers (polypropylene, barchip, and steel) and cured under either of the wet or combined (steam, autoclave, and water) conditions. A total of 282 cubic, cylindrical, and prism specimens were cast to measure their compressive and flexural strengths and determine toughness indices. It was found that the combined curing technique, proposed for the first time in this study, was capable of improving compressive strength in the specimens reinforced with synthetic fibers. Specimens containing barchip fibers as well as those containing steel fibers were found to present deflection-hardening behavior after cracking. Most of the specimens containing silica fume and limestone powder with different types of fibers showed satisfactory toughness indices, indicating their acceptable flexural toughness.