Study on Fracture Properties of Rubberized Concrete Based on Small Span-Depth Ratios

• The fracture mode is primarily Mode I. • The fracture parameters with different β values are calculated. • The allowable damage scale decreases as the β increases. • An increase in the β reduces the brittleness of rubberized concrete. Rubberized concrete exhibits excellent resistance to abrasion and provides a value-added method for recycling waste tires, thus demonstrating significant application potential in hydraulic engineering. To systematically study its fracture performance, this study used three-point bending beam specimens with span-depth ratios of 2.5, 3, 3.5, and 4 to characterize the fracture behavior of rubber concrete. The digital image correlation method was used to obtain full-field strain and displacement data on the specimen surfaces, enabling the observation of crack propagation paths. Subsequently, the fracture parameters of rubberized concrete beams with different span-depth ratios were calculated. The relationship between initial fracture toughness and span-depth ratio was established. The results indicate that the predominant fracture mode of rubberized concrete is Mode I fracture. The fracture performance of rubberized concrete is significantly affected by the span-depth ratio. As the span-depth ratio increases, the permissible damage scale decreases, the initial fracture toughness increases gradually, while the unstable fracture toughness decreases and gradually approaches a stable value. Furthermore, the ductility index increases significantly, indicating that an increase in the span-depth ratio effectively reduces the brittleness of rubberized concrete and enhances its toughness. These findings provide theoretical support and experimental evidence for the application of rubberized concrete in hydraulic engineering.