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Fracture energy of fiber reinforced high strength concrete
Date Issued
01-01-2005
Author(s)
Indian Institute of Technology, Madras
Raghu Prasad, B. K.
Abstract
This paper reports on some experimental investigations on the fracture energy and tension softening behavior of high strength concrete. Fibers are known to enhance the ductility and other performance requirements of concrete. With a small fraction of steel fibers, 0.62% by volume, the mode of failure changes from catastrophic to gradual. Further, with the addition of steel fibers, the energy absorption capacity of concrete increases very significantly. The compressive strength of fiber reinforced concrete is 70MPa and the tensile strength is 4.0 MPa. In the present case, the energy absorption in fiber reinforced concrete (FRC) is very high in comparison with the plain concrete. Though the experimental errors are inevitable, but they are negligible in comparison with the large energy absorption in FRC. The fracture energy in FRC decreases as the size of specimen increases. This indicates that the energy absorption decreases with increase in the size of specimen. It should lead to an understanding that the large size structures exhibit elastic behavior up to failure. It is further observed that the brittleness of concrete increases as the size of specimen increases. The compressive strength of plain concrete varies from 55 to 75 MPa, in which the increasing trend has been noticed with maximum size of coarse aggregate. As the heterogeneity in the matrix increases, the fracture energy also increases. In the specimens, one major crack is formed, which implies that the fictitious crack model can be used to FRC with small volume fraction of fibers.
Volume
31