Benefits of Using Fiber on Impact Resistance of FRC Slabs

The recent increase in terrorist attacks and natural disasters has led to increased requirements for concrete structures to be impact resistant. Concrete normally has excellent impact resistance to such extreme loads in comparison with other construction materials. Nevertheless, existing concrete structures designed without consideration of the impact or blast load with high strain rate are endangered by those unexpected extreme loads. Therefore, the impact resistances of two-way concrete slabs were studied by conducting the multiple impact test. Various fiber reinforcements (Hooked-steel fiber, straight-steel fiber) were considered as variables. In the impact test, the impact load was applied to each specimen by dropping weight on the specimen from a certain height. The applied impact load level was adjusted by changing the height of the weight. Specimens were used for impact loading test, each measuring 1,600mm long, 1,600mm wide, and 105mm thick. All slabs were doubly reinforced (top and bottom layer) and each layer in a specimen had the same reinforcement layout. The performances of the specimens under the impact load were evaluated by comparing their reaction force, deflection, and surface damage. The impact test was stopped when the measured reaction force started to decrease. Based on the impact test, it was observed that the resistance against impact load can be improved by using fiber reinforced concrete.