Pull-out and bond-slip performance of steel fibers with various ends shapes embedded in polymer-modified concrete

Abstract

The bond-slip behavior between matrix and fibers highly depends on the geometric and mechanical characteristics of fibers. Thus, by considering various geometric of fiber end shapes, the pull-out behavior of steel fibers from polymer-modified concrete is studied in the present study. For that, a three-dimensional non-linear finite element method is employed for simulations. For considering more real guess, interaction among matrix and fibers is simulated via Interfacial Transition Zone (ITZ), and its factors are attained from experimental results of the fiber pull-out test. After validating the results, the effect of geometric parameters of the fibers end shape on the bond-slip properties with polymer composite is investigated. The results from the load-slip curves indicate that there are different mechanisms in the behavior of the fibers depending on the diameter and angle of the fibers. For fibers with 2 mm diameter, increasing the angle of the hook from 0 to 90 degrees increases the pull-out force of hook and half-hook fibers by about 35% and 15%, respectively. Whereas a further increase in hook angle reduces pull-out parameters of the hook-shaped fibers. (C) 2020 Elsevier Ltd. All rights reserved.