Understanding the Role of Coral Powder in the Rheological, Shrinkage, and Mechanical Properties and Pore Structure of Coral Mortar

The content of coral powder in coral aggregates significantly impacts the quality of coral mortars using coral aggregates, ultimately affecting various properties of coral mortars. Hence, to elucidate the role of coral powder in coral mortars, this paper explores its impact on the properties of coral mortars. Additionally, mercury intrusion porosimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy are employed to unveil the underlying mechanisms through which coral powder enhances or diminishes the properties of coral mortars. The results illustrate that coral powder reduces the fluidity and increases the dynamic yield stress of coral mortars. Furthermore, due to its filling effect, coral powder facilitates enhancements in both the flexural and compressive strength of coral mortars. However, the refinement of pore size by coral powder, in turn, influences the shrinkage behavior of coral mortars. Simultaneously, coral powder diminishes the hydration and content of hydration products in coral mortar to a certain extent. The pore surface fractal dimension (Ds) was found to serve as a crucial indicator of strength. Notably, it displays a strong positive linear correlation with both compressive strength and flexural strength. Moreover, the composite exponential model proposed in this paper provides a more accurate simulation of the shrinkage behavior of coral mortars.