Title: Fluorescence Microscopic Study of Fracture Process of the Interfacial Zone Between a Steel Fiber and the Cementitious Matrix Under Pullout Loading

Author(s): M. Kawamura and S. Igarashi

Publication: Symposium Paper

Volume: 156

Issue:

Appears on pages(s): 173-190

Keywords: fibers; fluorescence; fracture properties; microscopy; microstructure; silica fume; toughness; Materials Research

DOI: 10.14359/945

Date: 9/1/1995

Abstract:
Fracture of the interfacial zone between a fiber and the cementitious matrix plays a significant role in the mechanical behavior of fiber reinforced cementitious composites. For better understanding of debonding characteristics of a fiber in the composites, the behavior of the extension of cracks along the interface was examined under the fluorescence microscope. The correspondence between the features of fracture zones obtained by the microscopic study and the fracture toughness for the interfacial zone is discussed in this paper. Examinations under the microscope revealed that the debonding and the extension of interfacial cracks were not caused by a simple shear failure at the actual interface, but were accompanied by local failures over relatively wide regions surrounding the steel fibers. The incorporation of silica fume resulted in the reduction in areas containing local failures along the interface. Fewer local failures in the interfacial zone in the steel fiber-silica fume-bearing cement composite were reflected by the decrease in the fracture toughness for the interfacial zone.