Volume 2, Issue 1 (January 2005)
The Role of Friction in Post-Crack Energy Absorption of Fiber Reinforced Concrete in the Round Panel Test
The Round Panel test has recently become standardized as C-1550 for post-crack performance assessment of Fiber Reinforced Concrete (FRC) and Shotcrete (FRS). This test involves the imposition of an out-of-plane point load at a constant rate of displacement to the center of a round panel supported on three symmetrically arranged pivots. Performance is measured in terms of the energy absorbed by the specimen up to a specified central deflection. Most of this energy is expended in the process of fiber deformation and pull-out from the concrete across cracks that form during the test. A significant proportion of the energy apparently absorbed by the specimen is actually lost to friction, however, as the panel fragments that form after cracking of the concrete slide outward in a radial direction across the supports. This investigation has been undertaken to determine the proportion of total energy absorption that is lost to friction as a result of this failure mechanism and to identify thereby how much energy is actually absorbed by the specimen.