Effect of the mesh size of diatomaceous earth immobilized microorganisms on the mechanical properties and microstructure of cement-based materials

Abstract

Diatomaceous earth (DE) possesses a unique pore structure, making it a promising candidate for microorganism immobilization. However, systematic research on the use of DE with varying mesh sizes in cement-based materials remains limited, particularly concerning its potential applications in microbial systems. This study investigates the effect of DE with varying mesh sizes, immobilized with microorganisms, on the mechanical properties and microstructure of cement-based materials. The focus is on the changes in DE's pore structure and pozzolanic activity under optimal immobilization conditions. The results show that cement-based systems with DE of different mesh sizes exhibit a reduction in early strength when compared to the control group. However, as curing progresses, performance gradually improves, with the system containing 800 mesh DE demonstrating a significant increase in long-term strength enhancement. Following microbial immobilization, DE shows a considerable reduction in porosity and a substantial increase in its pozzolanic activity. Further analysis reveals that the 800 mesh DE improves mechanical properties, hydration products, and pore structure, demonstrating significant modification effects. These findings provide valuable insights for optimizing cement-based materials.