Quantitative Analysis of Crack Propagation Behavior in Recycled Concrete Subjected to Axial Compression Using Digital Image Correlation (DIC) Technology and Fractal Theory

The current research endeavors to explore the mechanical properties of recycled concrete cubic specimens, predominantly concentrating on macroscopic attributes such as compressive strength and splitting tensile strength. However, at the mesoscopic scale, the internal structure of recycled concrete becomes increasingly intricate due to the adherence of substantial mortar on the surface of recycled coarse aggregates, ultimately influencing its macroscopic mechanical behavior and crack propagation trajectories. To address this complexity, Digital Image Correlation (DIC) technology is harnessed to quantitatively analyze crack tip displacement fields and crack propagation behavior in recycled concrete, considering variations in aggregate replacement ratios and particle sizes. This analysis encompasses quantitative assessments of pre-cracking damage, post-cracking crack morphology characteristics, and size. Utilizing the advanced 3D-DIC algorithmic technique, this study delves into the evolution of crack propagation patterns in recycled concrete during the loading process, evaluating the impact of both aggregate replacement ratios and particle sizes on crack propagation behavior. Ultimately, fractal theory is employed to provide a quantitative analysis of the crack morphology on the surface of recycled concrete.