7.15 : 繊維強化コンクリート

Fiber-reinforced concrete is made of hydraulic cement with fine or coarse aggregates, incorporating separated, non-continuous fibers.

These fibers can be natural, like asbestos, or manufactured from glass, steel, or polymers, such as polypropylene.

Steel fibers are predominantly used to enhance concrete's structural and nonstructural properties. Fiber lengths range from three-fourths to two and a half inches.

The proportion of fiber volume categorizes the fiber-reinforced concrete. Less than one percent of fibers helps avoid shrinkage cracking in the concrete.

Fibers between one and two percent increase the modulus of rupture, toughness, and impact resistance, while more than two percent cause strain hardening from plastic deformation.

Plain concrete breaks upon reaching ultimate flexural strength, while fiber-reinforced concrete exhibits continued load-bearing and enhanced ductility and post-cracking performance.

Fiber characteristics in concrete include the aspect ratio, shape, texture, and structure. The maximum stress a fiber can bear relates to its aspect ratio, the length-to-diameter ratio.