Influence of fiber content and specimen size on fracture property of polypropylene fiber concrete

In order to study polypropylene fiber concrete´s fracture properties, the polypropylene fiber concrete with different fiber content and size under three-point bending was researched, and the fracture energy, unstable fracture toughness and critical crack tip opening displacement of the polypropylene fiber concrete in modified double-K criterion parametric model were also analyzed. The result indicated that any influence coefficient of the different specimen sizes was approximately similar with different fiber volume ratio; polypropylene fiber had biggish enhancement effect to the concrete, and there was a optimum fiber content of 0.9kg/m³.