PSI - Issue 66

Bineet Kumar et al. / Procedia Structural Integrity 66 (2024) 337–343 Author name / Structural Integrity Procedia 00 (2025) 000–000

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5. Result and discussions Stress-Strain Behavior

Fig. 4 illustrates the stress-strain behavior for both the fiber contents. It is evident that the tensile stress observed for the 2.5% fiber content is higher compared to the 1.5% fiber content. In specimens with lower fiber content, the micro/matrix cracking phase persists for a longer duration due to insufficient fibers, leading to a significant and sudden drop in stress. Conversely, for 2.5% fiber content, the fiber-bridging phase initiates earlier, resulting in less reduction in stress. Additionally, the fiber-bridging phase extends to a similar strain level for both fiber contents. Effect of Fiber Content The presence of fibers significantly impacts the fracture behavior of the concrete matrix, altering the stress profile (Fig. 5). With a higher fiber content, the stress does not decrease sharply during the micro/matrix cracking phase and exhibits a plateau-like response in the fiber-bridging phase. On the other hand, lower fiber content leads to a more pronounced reduction in stress during matrix cracking. Although stress begins to increase during the fiber-bridging phase, the initial drop is more substantial. This can be attributed to the fact that stress reaches a lower value during the matrix-cracking phase, creating more room for an increase once fiber-bridging begins. However, this increase is limited in the fiber-bridging stage when the fiber content is higher. Moreover, the stress-crack width behavior remains nearly same in both the cases. In terms of crack propagation, the behavior is similar across both fiber contents. However, the bridging effect is more pronounced with 2.5% fiber conte which slows down the rate of crack propagation.

Fig 2. Material models and fibre orientation