Mechanical behavior and models for porosity-free concrete reinforced with high amounts of steel fiber

•Mechanical properties of porosity free concrete were investigated in several material tests.•Compressive stress–strain curve and tension softening curve were modeled.•Equivalent characteristic length (average crack spacing) was obtained by numerical analysis.•Tensile stress–strain relationship was proposed by using equivalent characteristic length. A new cementitious composite characterized by an extremely high compressive strength (>400 MPa), known as porosity-free concrete (PFC), has been recently developed. Many tests have been conducted to formulate appropriate stress–strain laws for compression and tension. This study clarified that PFC has extremely high compressive strength and post-cracking toughness owing to the reinforcing fibers. In addition, the flexural strength of porosity-free concrete was investigated by combining experimental and numerical analyses. Furthermore, the formulation of the stress–strain law in tension introduced “equivalent characteristic lengths” to convert the crack width into an equivalent strain. (93 words)