Experimental study on the influence of particle size and type on single particle breakage of construction waste

Construction waste is characterized by heterogeneous type, irregular morphology, and complex internal architecture. The primary constituents include recycled mortar (RM), recycled brick (RB), and recycled concrete (RC). To systematically investigate the comprehensive influence of different particle types and particle sizes on the breakage behavior of construction waste particles, a series of single-particle compression tests was conducted. The characteristic breakage strength and strength variability were quantitatively evaluated using the Weibull distribution function. Fractal dimension analysis was performed by comparing gradation curves before and after breakage. According to the experiments, the particle size and type have a coupled effect on single particle breakage behaviors of construction waste. The Weibull modulus ( m ) and fractal dimensions ( D ) show that with the increase of particle size, the breakage strength dispersion of RM and RB decreases, whereas that of RC increases. Particles with the lower breakage strength exhibited a greater propensity for fragmentation, demonstrating pronounced fractal characteristics consistent with established construction waste fractal models. Based on the force-displacement characteristics and fragmentation patterns, three distinct breakage modes were identified: intermediate splitting, mixed breakage, and bulk breakage. The proportions of different breakage modes varied with particle types and sizes. In general, as particle size increases, the dominant breakage mode of RM and RB transitions from bulk breakage to mixed breakage, whereas intermediate splitting mode becomes the predominant breakage mode of RC particles. The research results can provide technical insights into the breakage characteristics of construction waste materials and offer potential guidance for engineering applications.