Title: Properties of Steel Fiber Reinforced Concrete Subjected to Impact Loading

Author(s): V. S. Gopalaratnam and S. P. Shah

Publication: Journal Proceedings

Volume: 83

Issue: 1

Appears on pages(s): 117-126

Keywords: composite materials; concretes; cracking (fracturing); impact; deflection; dynamic loads; fiber reinforced concretes; impact tests; loading rate; loads (forces); metal fibers; microcracking; strains.

DOI: 10.14359/1750

Date: 1/1/1986

Abstract:
The effect of strain rate on the flexural behavior of unreinforced matrix and three different fiber reinforced concrete (FRC) mixes are discussed. Results obtained from the modified instrumented Charpy tests on cement composites compare well with results from several similar investigations that use an instrumented drop-weight setup. FRC mixes are more rate-sensitive than their respective unreinforced matrices, showing increases in dynamic strength (strain rate of 0.3/sec) of up to 111 percent and energy absorption (up to a deflection of 0.1 in. {2.5 mm}) of up to 70 percent (vf = 1.5 percent) over comparable values at the static rates (strain rate of 1 x 10-6/sec). Composites made with weaker matrices, higher fiber contents, and larger fiber aspect ratios are more rate-sensitive than those made with stronger matrices, lower fiber contents, and smaller fiber aspect ratios. Several observations made in the study suggest that the rate sensitivity exhibited by such composites is primarily due to a change in the cracking process at the different rates of loading. Relative improvements in performance due to the addition of fibers as observed in the instrumented tests are compared with those from the conventional impact and static tests. The comparison shows that static flexural toughness tests may be used to approximately estimate the dynamic performance of FRC.