Micromechanics of Fracture Propagation in Tailings-Based Ceramics

The extraction and processing of minerals and metals generates large quantities of mine tailings (MTs), a byproduct that has grown in volume due to rising global demand and technological advancements. Disposing of large quantities of MTs on land leads to various environmental issues, including acid mine drainage and soil degradation. Recently, converting MTs into construction materials has emerged as an eco-friendly solution for environmental preservation. Tailings-based ceramic is a sustainable product that is produced from MTs via a combination of forming and sintering and can be used for a variety of applications, including bricks, substrates, and roof tiles. Ceramics exhibit brittle or quasi-brittle characteristics depending on their compositional elements and manufacturing process. Therefore, understanding their strength and fracturing behavior is essential prior to their widespread use. This study aims to investigate the fracture properties of tailings-based ceramics using advanced techniques such as digital image correlation (DIC) and acoustic emission (AE) monitoring. A series of semi-circular ceramics were fabricated as notched semicircular bending (NSCB) specimens subjected to three-point bending loading. The brittle fracture of specimens was controlled by attaching a highly precise clip-on extensometer to the sides of the pre-existing notch. The fracturing experiments were continuously monitored using calibrated AE and DIC techniques to characterize the fracture process zone (FPZ) and identify the cracking mechanisms. The polarity technique was employed to categorize the detected AE events into opening (tensile), sliding (shear), or collapse (compaction) types. This detailed fracture characterization helped improve our understanding of the behavior of this new material and aid in its optimization for further use.