Although shotcrete reinforced with polypropylene fiber was first used in Europe in 1968, it was not until 1988 that a high volume of polypropylene fiber was successfully used in a shotcrete application. Conditions related to crack resistance and rebounding had resulted in a compromise on steel fiber length, making the mid-range length most commonly specified. Because of the low modulus or flexible nature of the polypropylene fibers, it was hoped that longer fibers and higher volumes could be used without causing problems of manageability in the field.
