Control of Tensile Behavior of Ultra-High Performance Concrete Through Artificial Flaws and Fiber Hybridization

Ultra-high performance concrete (UHPC) is one of the most promising construction materials because it exhibits high performance, such as through high strength, high durability, and proper rheological properties. However, it has low tensile ductility compared with other normal strength grade high ductile fiber-reinforced cementitious composites. This paper presents an experimental study on the tensile behavior, including tensile ductility and crack patterns, of UHPC reinforced by hybrid steel and polyethylene fibers and incorporating plastic beads which have a very weak bond with a cementitious matrix. These beads behave as an artificial flaw under tensile loading. A series of experiments including density, compressive strength, and uniaxial tension tests were performed. Test results showed that the tensile behavior including tensile strain capacity and cracking pattern of UHPC investigated in this study can be controlled by fiber hybridization and artificial flaws.