## 1 Introduction  
Reinforced concrete (RC) beams are the primary load-bearing components in building structures, and their main modes of failure are bending failure and shear failure [1, 2, 3, 4, 5]. When a concrete beam undergoes shear failure, it exhibits distinct brittle characteristics, with poor ductility and significant difficulty in reinforcing or repair [6, 7, 8, 9]. Therefore, when the shear bearing capacity of concrete beams is inadequate, it is important from an engineering perspective, to improve their shear performance and ameliorate their shear failure modes by using new materials and technologies [10, 11, 12, 13, 14]. Existing conventional reinforcing methods mainly include increasing the cross-section [15, 16, 17, 18], bonding steel plate reinforcements [19, 20], and bonding fiber-reinforced composite reinforcements [21, 22, 23]. However, these reinforcement methods possess certain deficiencies. For instance, increasing the cross-section significantly impacts the structure's self-weight. In the bonded steel plate method, the performance of the adhesive material directly affects the bonding effectiveness; if the bonding performance is insufficient, it reduces the reinforcing effect. Carbon fiber has poor fire resistance and requires high standards for adhesive materials and construction techniques. Carbon fiber has poor fire resistance and requires high standards for adhesive materials and construction techniques. Among other strengthening materials, ECC (Engineered Cementitious Composite) has low tensile strength and cracks prematurely, making it generally unsuitable as a standalone reinforcement material [24; 25; 26]. Polyurethane mortar has a propensity to react with moisture during its preparation, generating copious amounts of bubbles, which affects the performance of the material [27]. The actual preparation environment in engineering applications often cannot meet the requirements, and its long-term stability still needs to be verified. All the above reinforcement methods have a longer construction period, which results in significant impacts on traffic during bridge reinforcement. In contrast, epoxy resin mortar, using epoxy resin as the base material, has good fluidity and is easy to apply. Its hardening time is shorter, allowing for the restoration of traffic in a relatively short period after reinforcement [28; 29]. Additionally, it offers advantages, such as its fire-resistant property [30; 31], better bonding, resistance to delamination, and high tensile strength. However, the toughness limitation of commonly used epoxy mortars should not be overlooked. Specifically, the ultimate tensile strain is typically lower than 1500 \(\mu\varepsilon\), which is significantly lower than the yield strain (2000 \(\mu\varepsilon\)) of stirrup in concrete structures and the design ultimate tensile strain (10,000 \(\mu\varepsilon\)). This means that, before the original structural reinforcement reaches its yield point, the epoxy resin mortar may fail due to cracking, thus losing its ability to function effectively. Therefore, in reinforcement engineering, epoxy resin mortar is typically employed as a bonding material. It bonds reinforcing materials (e.g., high-strength steel wires, fiber-reinforced bars, and steel cables) to the reinforced beams, enabling them to work together under load, thereby enhancing the structural load-bearing capacity. However, due to its tendency to crack prematurely, the epoxy resin mortar itself does not contribute directly to increasing the load-bearing capacity of the structure but rather serves primarily as an adhesive [32; 33]. To address this issue, our research team has incorporated chemical toughening agents into the epoxy resin mortar to form an interpenetrating network structure at the microscopic level, thereby alleviating its brittleness [34; 35]. We have developed a novel high-strength, high-toughness epoxy mortar that exhibits high tensile strength (19.4 MPa) and ultimate tensile strain (>10,000 \(\mu\varepsilon\)).