لخّصلي

The authors used an experimental research approach combining mechanical testing, monitoring techniques, and microstructural analysis to study damage and fracture behavior of steel fiber-reinforced concrete (SFRC).Specifically, they employed the following methods and experiments: o Three-point bending fracture tests on notched SFRC beams with different steel fiber contents to evaluate bending damage, load-CMOD behavior, flexural-tensile strength, and fracture toughness.o Scanning Electron Microscopy (SEM) to analyze the microstructure and fracture surfaces after testing, identifying mechanisms such as fiber bridging, debonding, and pull-out.

The authors used an experimental research approach combining mechanical testing, monitoring techniques, and microstructural analysis to study damage and fracture behavior of steel fiber–reinforced concrete (SFRC).

Specifically, they employed the following methods and experiments:
• Three-point bending fracture tests on notched SFRC beams with different steel fiber contents to evaluate bending damage, load–CMOD behavior, flexural–tensile strength, and fracture toughness.
• Acoustic Emission (AE) monitoring during loading to capture microcrack initiation, crack propagation, and internal damage evolution in real time.
• Digital Image Correlation (DIC) to observe surface strain fields and track crack initiation and propagation during the bending tests.
• Fracture mechanics analysis using the double-K fracture criterion to calculate crack initiation toughness, instability toughness, and cohesive toughness from load–CMOD curves.
• Fractal analysis of AE time-series data, where the Grassberger–Procaccia algorithm was applied to calculate the correlation dimension and characterize crack evolution and damage states.
• Scanning Electron Microscopy (SEM) to analyze the microstructure and fracture surfaces after testing, identifying mechanisms such as fiber bridging, debonding, and pull-out.

Together, these experimental methods allowed the authors to link macroscopic bending behavior with microcrack evolution and fractal damage characteristics in SFRC beams