Title: Flexural Toughness of Steel Fiber Reinforced Concrete

Author(s): P. Balaguru, Ramesh Narahari, and Mehendra Patel

Publication: Materials Journal

Volume: 89

Issue: 6

Appears on pages(s): 541-546

Keywords: fiber reinforced concrete; fibers; high-strength concrete; load-deflection curve; silica fume; toughness; Materials Research

DOI: 10.14359/4019

Date: 11/1/1992

Abstract:
Results of an experimental investigation on the flexural behavior of steel fiber reinforced concrete (SRC) are reported. Even though a number of investigations had been carried out in this area, comprehensive results on toughness behavior are not available, especially for FRC reinforced with deformed fibers. In addition, a relatively new procedure was used to measure the deflections accurately. The accurate measurement of deflections leads to significant changes in toughness values. The variables investigated were: fiber type, length, and volume fraction; and matrix composition. Three fiber types, three fiber lengths, four fiber volume fractions, and four matrix compositions were evaluated. The results indicate that fiber content in the range of 50 to 100 lb/yd 3 (30 to 60 kg/m 3) provides excellent ductility for normal strength concrete. The fiber content has to be increased to about 150 lb/yd 3 (90 kg/m 3) for high-strength concrete. Hooked-end fiber geometry provides better results than corrugated and deformed-end geometry. Fiber length, in the range of 1.18 to 2.36 in. (30 to 60 mm), does not have a significant effect on toughness for hooked-end fibers. Ductile behavior can be obtained using 200 lb/yd 3 (120 kg/m 3) of fibers, even for concrete containing 20 percent silica fume by weight of cement. Some of the toughness index values specified in ASTM are not sensitive enough to differentiate any of the variables investigated in this study.