Effects of CaCO3 and SiO2 contents on mechanical and acoustic emission properties of gypsum materials

Simulative research is a fundamental approach to investigating ground pressure mechanisms. In model testing, understanding how compositional changes affect similar materials' mechanical and acoustic emission properties is crucial. This study examines the effects of calcium carbonate (CaCO3) and silicon dioxide (SiO2) on gypsum materials' mechanical and acoustic emission properties through laboratory tests, crystal structure analysis, and mathematical modeling. The results indicate that CaCO3 and SiO2 have a significant impact on compressive strength, while their effect on tensile strength is less pronounced. Specifically, CaCO3 reduces strength and accelerates yielding, whereas SiO2 increases strength and elastic modulus. Acoustic emission analysis reveals a negative correlation between cumulative energy release and CaCO3 content, while higher SiO2 content leads to greater energy release during fracture. CaCO3-rich samples exhibit numerous cracks and dislocation closures during the elastic stage, compromising stability before yield stress. In contrast, SiO2 promotes smoother crack closure and a clearer yield point, enhancing both stability and impact resistance. Structurally, the silico-oxygen tetrahedral bonds in SiO2 provide greater stability than the ionic bonds in CaCO3. Based on mechanical parameters such as uniaxial strength, tensile strength, peak strain, and elastic modulus, a mathematical model is developed to describe property variations with different compositions. Regardless of the CaCO3 and SiO2 ratios, a quadratic correlation is observed in the rate of change of mechanical parameters. The application of a neural network approach enables the calculation of real and imaginary components in the complex plane model, enhancing its practical applicability.