Meso-damage mechanism of sintered sludge cementitious composites under uniaxial compression: Experimental characterization and theoretical modeling

Abstract

Considering the performance and environmental potential of sintered sludge cementitious composite (SSCC), this research comprehensively evaluated the meso-damage mechanism of SSCC under uniaxial compression through experimental characterization and theoretical modeling. Specifically, advanced techniques such as acoustic emission (AE), digital image correlation (DIC), low-field nuclear magnetic resonance (LFNMR), and scanning electron microscopy (SEM) were employed to deeply characterize the damage responses, meso-structures and damage morphology. Theoretical modeling based on the classical damage theory (CDT) framework established a stochastic damage constitutive (SDC) model to elucidate the intrinsic relationship between meso-damage mechanism and macro-performance. Results demonstrated that the stress-strain behavior, energy response, and macro-cracks evolution of SSCC, showing distinctly different behaviors before and after the peak point on the constitutive curves, were accurately predicted by SDC model. LFNMR and SEM confirmed that macro-damage originated from interfacial transition zone (ITZ) fracture. Furthermore, SDC model verified that 5 % SSA effectively enhanced the elasticity and ductility of meso-structure, thereby significantly improving the macro-performance and damage resistance.