Application of various fractal models in characterizing the morphology of pore structures of hydrating cement pastes

Abstract

The pore structures of cementitious materials are very crucial to the development of the various engineering properties of these materials. Based on the importance of the pore structure, several studies have been conducted on the application of fractal geometry, which can be used as an interpretation tool for the characteristics of the pore structure as well as in various engineering phenomena. Accordingly, various fractal models have been developed from the mercury intrusion porosimetry (MIP) data. However, studies on applying the fractal model considering the characteristics of the material to be analyzed are relatively scarce. In this study, we conducted an in-depth investigation of the characteristics of the pore structures of cementitious materials considering both the volumetric and geometric characterization parameters. Among the three concepts of fractal dimensions of pore-size distribution, the solid mass fractal concept exhibited the highest correlation with the degree of hydration. The fractal dimensions of pore-size distribution and pore tortuousness tended to increase as the complexity of the entire microstructures increased, mainly due to the increase in the solid phase fraction. Furthermore, the results of the correlation analysis (between the volumetric and geometric parameters) and regression analysis (between newly derived parameter and initial sorptivity) showed that fractal dimensions can be utilized as pore structure characterization parameters like the existing volumetric parameters, and these parameters serve as complementary tools for interpreting the transport properties of cementitious materials.

Keywords

• Fractal concept
• Geometric perspective
• Hydration
• Pore structure
• Sorptivity