## 1 Introduction  
Concrete is strongly known for its high compressive strength; nonetheless, because of its inherent brittleness and small tensile strength, it is prone to cracking under various loading conditions. Crack initiation and crack growth are crucial to investigating concrete structures' energy capacity of dissipation, particularly under cyclic and dynamic loading conditions. At the onset of crack initiation, energy is expended to overcome the material's cohesive strength and create new crack surfaces. This process contributes to the fracture energy, which is a significant component of the total energy dissipation in the material. Under further loading, micro-cracking and plastic deformations are initiated at the crack tip, contributing to energy dissipation. However, when an extensive crack forms uncontrollably in plain, unconfined concrete, it reduces the load-carrying capacity and energy dissipation. This redaction produces a smaller hysteresis loop area that restricts the material from absorbing energy. To overcome the weaknesses of concrete behavior, fiber-reinforced concrete (FRC) has been developed to enhance concrete's tensile performance and energy absorption. Fibers in the concrete matrix function as crack-bridging reinforcements, altering the crack propagation mechanism. Fibers transfer tensile loads across crack surfaces upon crack formations, requiring additional energy for crack propagation. This action increases ductility and extends the hysteresis loop area under cyclic loading. Instead of a single catastrophic fracture, fiber-reinforced composites promote a micro-crack-distributed formation, each of which helps in energy dissipation. Moreover, fibers exert frictional resistance and pull-out mechanisms, dissipating energy as cracks propagate through the material. Several experimental and analytical studies have examined the effectiveness of fibers in enhancing the toughness and energy-dissipating capability of concrete at a fracture. It was demonstrated that adding rubber powder and recycled steel fibers (RSF) significantly increased the ductility of concrete, and it has been established that fibers ensure a more controlled process of crack growth through damage distribution [1]. Similarly, it was shown that the crack bridging by fibers is a prevailing mechanism of toughening, which is more energy intensive for crack growth and contributes towards improved energy absorption [2]. It was stated that ultra-high-performance concrete (UHPC) exhibited superior mechanical performance by way of controlled micro-cracking and fiber pull-out, both contributing towards improved energy dissipation due to the distributing of damage over greater material volume [3]. It was further demonstrated that the incorporation of fibers led to a spectacular increase in fracture energy, with rises of 850%, 770%, and 450% being reported for various concrete strengths [4]. The significance of the fiber pull-out and crack bridging mechanisms was proved through advanced 3D imaging techniques, and it was concluded that 3.5-4.0% steel fiber volumes led to a hundred-fold rise in energy dissipation [5]. The above findings were supported by analyzing the flexural behavior of hybrid polypropylene and SFRHSC beams, demonstrating that fiber interaction significantly enhanced post-cracking toughness and delayed crack localization, emphasizing the role of fibers in triggering distributed damage and promoting energy dissipation [6]. Additional details were provided on the uniaxial tensile response of ultra-high-performance fiber-reinforced concrete (UHPFRC) [7], which indicated that the fibers resulted in a more dispersed cracking pattern and an appreciable enhancement in energy absorption capacity. The contribution of fiber content in determining the post-cracking tensile stiffness of fiber-reinforced UHPFRC was emphasized, showing that higher fiber volume fractions led to higher energy dissipation due to more energy being required to extend cracks in the material [8].