A comprehensive performance evaluation and optimization of steel/carbon fiber-reinforced eco-efficient concrete (FREC) utilizing multi-mechanical indicators
Fei Zhao, Zhenming Shi, Qingyan Li, Songbo Yu, Maomao Liu
Abstract
Fiber-reinforced eco-efficient concrete (FREC), as a new composite material with super high mechanical properties, has been widely used in the engineering construction. This paper reports a series of mechanical tests, covering the uniaxial compression test (UCT), Brazilian splitting test (BST), axial compression test (ACT), and four-point bending test (FBT), aimed at delving into the mechanical attributes and failure behavior of FREC incorporating steel fibers (SF) or carbon fibers (CF), with a range of dosage: 0.0 %–3.5 % straight steel fibers (SSF), 0.0 %–3.5 % hooked steel fibers (HSF), and 0.0 %–0.5 % CF. The key findings unveil the superiority of SF over carbon CF in enhancing concrete strength and elastic modulus . With the increment of fiber dosage, the mechanical parameters of FREC follow two distinct trends: one is a continuous increase; the other is an initial increment succeeded by a decrement. During the failure process, non-fiber-reinforced concrete (NFRC) and carbon fiber-reinforced eco-efficient concrete (CFREC) experience complete separation upon failure, while steel fiber-reinforced eco-efficient concrete (SFREC) exhibits delayed fracture expansion, marked by a conspicuous "fracturing but continuous” phenomenon. Furthermore, SF induces an alteration in the fracture patterns of concrete, transitioning from tensile failure to shear failure or tensile-shear failure. This study also focuses on a performance optimization and evaluation model, assessing the impact of SF and CF on a spectrum of mechanical parameters , such as strength , ductility, toughness, and cracking-resistance of FREC. Results underscore the efficacy of 3.5 % SSF in enhancing four key indicators: strength, deformability , toughness, and cracking resistance , while 3.5 % HSF improves ductility and cracking-resistance, and 0.5 % CF enhances ductility. These findings offer vital theoretical support for the deployment of FREC in anti-slide pile structures for rocky landslide scenarios, bearing substantial engineering implications.