Nanostructure and Microstructure of Cement Concrete Incorporating Multicementitious Composites

The nanostructural and microstructural behavior of concrete plays a decisive role in determining the properties of a material. The pore structure of paste, mortar, or concrete affects the behavior of the material and can give insight into the material's nanostructure and microstructure and their performance. Permeability and other durability-related properties of concrete are directly affected by pore structure. The pore structure also influences strength, modulus of elasticity, volume stability, and environmental resistance. Therefore, pore size, extent, and shape are of paramount importance in deciding the suitability of materials for practical applications, and the determination of pore structure has vital importance in evaluating the performance of concrete. This investigation was performed to assess and understand the influence of fly ash and silica fume as cement replacements on the pore structure of mortar. The pore structure study was conducted by using mercury intrusion porosimetry on the cement mortar incorporating fly ash and silica fume as partial cement replacements for the preparation of various combinations of blended systems. It was observed that incorporation of fly ash has a slight pore refinement effect, while inclusion of silica fume significantly improved pore refinement.