Title: Evaluation of Bond-Slip Behavior of Twisted Wire Strand Steel Fibers Embedded in Cement Matrix

Author(s): C. Sujivorakul and A. E. Naaman

Publication: Symposium Paper

Volume: 206

Issue:

Appears on pages(s): 271-292

Keywords: bond, bond-slip, fiber reinforced concrete, frictional, mechanical, pullout test, shear stress

DOI: 10.14359/12258

Date: 4/1/2002

Abstract:
The bond stress versus slip behavior of steel fibers cut from twisted wire strands (which are made from at least two round steel wires wrapped helically around each other) is investigated and compared to the behavior of a single triangular steel fiber (Torex) twisted along its axis. Single fiber pullout tests simulating fiber pullout in a cracked tensile specimen were used. Parameters investigated are: 1) the embedded length of the fiber in the matrix; 2) the number of individual wires making a strand fiber; 3) the pitch distance of the fgiber; 4) the compressive strength of the mortar matrix (44 and 84 Mpa); and 5) the tensile strength of the fiver. It is observed that, depending on the combination of parameters (embedded length, matrix, strand type and pitch distance) the bond stress-slip response can be elasto-plastic in shape or slip softening after the peak. However, the twisted wire strand fibers are less efficient than the single Torex fiber, in terms of peak pullout load and pullout energy.