A study was made of a method for increasing the durability of concrete structures by reinforcing concrete with short fibers to prevent the falling of covering concrete due to corrosion and expansion of reinforcing bars. Fiber-reinforced concrete is required to (1) prevent concrete from falling, (2) have little influence on concrete composition and construction and (3) be economical. Steel fibers, which are generally used, and four types of organic fibers were examined. As a result of the study, it was found that the number of fibers added to concrete had a greater influence on the prevention of concrete falling than the strength of the fiber and that adding more than 300, 000 fibers per cubic meter could prevent covering concrete from falling.
