TOUGHNESS INDEXES OF STEEL FIBER-REINFORCED CONCRETE AT SUBZERO TEMPERATURES

This paper presents some micromechanical and macromechanical test data for steel fiber reinforced concrete at normal (22-degrees-C) and at low (-50-degrees-C) temperatures. Micromechanical tests were in the form of fiber pull-out tests with the fiber aligned in the direction of the applied pull-out load. In the macromechanical tests, steel fiber reinforced concrete beams were loaded at triple points (4-point loading). Two levels of matrix strength, normal and high, were investigated. Strengths in all cases were higher at -50-degrees-C than at 22-degrees-C. Toughness at -50-degrees-C, on the other hand, was marginally reduced for composites with a normal strength matrix and drastically reduced for those with a high strength matrix.