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 optimumfiber content of 0.9kg/m
³
.