Title: Performance Characteristics of Fiber Reinforced Concretes with Low Fiber Contents

Author(s): V. Ramakrishnan, W. V. Coyle, V. Kulandaisamy, and Ernest K. Schrader

Publication: Journal Proceedings

Volume: 78

Issue: 5

Appears on pages(s): 388-394

Keywords: compression tests; compressive strength; consistency tests; cracking (fracturing); fatigue tests; fiber reinforced concretes; flexural strength; flexural tests; high strength concretes; impact strength; metal fibers; performance; static tests; workablity.

DOI: 10.14359/10524

Date: 9/1/1981

Abstract:
This report presents the performance characteristics of fiber reinforced concrete with low fiber content. The fibers used were 2 in. (XI mm) long collated fibers with deformed ends which are glued together side by side into bundles (collated) with a water-soluble glue. The test program included (1) compressive strength; (2) static flexural strength including deflection, modulus of rupture, load-deflection curves, determination of first crack load, and determination of postcracking strength; (3) flexural fatigue; (4) impact strength to first crack and ultimate failure; (5) pulse velocity and static and dynamic modulus of elasticity; and (4) plastic mixing. The complete series of tests was run for three concentrations of the collated and hooked fibers and for the corresponding concrete without the addition of fibers. All fiber reinforced concretes showed a tremendous ability to absorb impact loading. Collating enables the fibers to be mixed with aggregates without balling or tangling and these fibers were easy to handle. The static flexural test shows that an excellent end anchorage is established in the case of hooked fibers. The addition of hooked and collated fibers, even in small quantity [42 Jb/cu yd (24.9 kg/m3)] considerably improves the post-load-carrying capacity and increases the toughness index and energy absorbing capacity resulting in a high ductility of the composite material. One serious drawback of high strength concrete is its Jack of ductility; this drawback could be overcome with the addition of small quantities of hooked steel fibers which will increase the ultimate strain capacity of the concrete and provide adequate ductility.