Title: Toughness of fiber-Reinforced High-Strength Concrete from Notched Beam Tests

Author(s): D. Jamet

Publication: Symposium Paper

Volume: 155

Issue:

Appears on pages(s): 23-40

Keywords: beams (supports); cracking (fracturing); ductility; fibers; fiber reinforced concretes; high-strength concretes; silica fumes; steels; tests; toughness; Materials Research

DOI: 10.14359/927

Date: 8/1/1995

Abstract:
The toughness of fiber reinforced concretes (FRC) was characterized from notched beam tests. The tests were performed under CMOD control in a servo-hydraulic machine to obtain the stable response of both the unreinforced concrete and the FRC. Several toughness measures were defined in terms of the experimentally obtained load versus crack opening (CMOD) curves. They give a better indication of the fundamental behavior of the concrete, avoid the problems associated with the approach based on the deflection of unnotched beams, and are amenable to the incorporation of serviceability considerations (for example, crack widths). The effect of specimen size on toughness was found to be significant in both the matrix- and fiber-dominated regimes of the FRC behavior. In general, toughness increases with specimen size and needs to be accounted for in the characterization. The study was conducted on beams of a 70 MPa compressive strength silica fume concrete, with and without high-strength hooked steel fibers. It was found that the incorporation of a low volume fraction (one percent) of steel fibers is sufficient to significantly decrease the brittleness of high-strength concretes.