Flexural performance of reinforced Alkali-activated concrete beams incorporating steel and structural Macro synthetic polypropylene fiber

Abstract

Lately, alkali-activated concrete (AAC) has gained attention due to the environmental impact that Ordinary Portland Concrete (OPC) possesses and durability issues. This paper investigates the flexural behavior of reinforced AAC beams adding 1.5% structural macro synthetic polypropylene fiber and 5% hooked end steel fiber structural, including control. The fiber addition was relevant to the total binder weight. Six beams of 100 mm × 200 mm × 1200 mm beams reinforced with two steel bars of 12 mm in diameter were cast and tested under a four-point loading test. This study evaluated the cracking moment, ultimate load, mid-span deflection, energy absorption, toughness, displacement ductility, failure mode, and crack patterns at yielding and ultimate capacity. The addition of fibers, especially steel fibers, significantly increased the flexural capacity. The steel fiber addition to the AAC beam specimen showed remarkable failure mode. It disturbed the crack pattern due to the fiber action that acted as a bridge controlling the crack propagation and transferring stress from the AAC to the steel fibers. Also, this study evaluated several codes and guidelines provisions in terms of flexural capacity and deflection. The ACI 318 showed conservative predictions rather than ECP 203 and EN 1992–1. Furthermore, a finite element model (FEM) using “ANSYS” was developed and validated. The FEM results provided a good agreement with the experimental results.