Physical and Mechanical Properties of Steel-Fiber Reinforced Dry-Mix Shotcrete

Investigators tested dry-mix shotcrete reinforced with various contents of four different types of steel fiber to evaluate in situ fiber content; fiber orientation; and influence on mechanical properties, compressive and tensile strength, modulus of elasticity, and post-crack reinforcing ability. Theoretical models are proposed and tested to assess fiber loss and fiber orientation inside shotcrete. Results show that although dry-mix shotcrete has some very distinct characteristics compared to the cast concrete matrix, steel fiber reinforced shotcrete is somewhat similar to the unreinforced dry-mix shotcrete matrix with respect to mechanical properties up to the first crack. After this point, its reinforcing ability appears to be dependent not only on fiber type and content, but also on the set-accelerator admixture and fiber orientation.