TOUGHNESS CHARACTERIZATION OF STEEL-FIBER REINFORCED-CONCRETE

The paper describes an experimental program in which four deformed commercial fibers with widely different geometries were investigated in steel-fiber reinforced concrete. Three matrices with compressive strengths of 42, 52, and 85 MPa were reinforced with fibers at a dosage rate of 40 kg/m(3). Compressive and flexural strengths were measured along with the elastic moduli. The focus of the study, however, was to measure and characterize the toughness improvements in the basic matrices due to the addition of various fibers. To this end, flexural load-deflection curves were analyzed in accordance with the ASTM and Japan Society of Civil Engineers (JSCE) standard methods and also using a proposed-analysis scheme. The paper points out the limitations of the current techniques of toughness characterization and identifies this as an area with immediate research needs. For the fibers and the matrices investigated, a strong influence of both fiber geometry and matrix strength on the toughness characteristics of fiber-reinforced concrete was observed. End-deformed fibers were, in general, found to perform superior to those deformed throughout the length.