The text discusses the effect of nanomaterials (NS and CNTs) on the uniaxial compression properties of Engineered Cementitious Composites (ECCs). The compressive strength and peak compressive strain of ECC specimens were tested with different nanomaterial concentrations. The results show that the addition of nanomaterials improves the compressive strength and peak compressive strain of ECC. The compressive strength and peak compressive strain of the NS series exhibit an initial increase, followed by a decrease as the concentration of nanomaterials increases, with the ideal NS content being 2%. In contrast, the CNTs series shows a more consistent increase in compressive strength and peak compressive strain with the ideal content being 0.15%.
The study also investigates the effect of nanomaterials on the microstructure of ECC. The results show that the incorporation of NS enhances the density of the matrix, improves the structure of the interfacial transition zone, and reduces the number of cracks. The XRD analysis shows that the addition of NS consumes more CH crystals, generating an increased quantity of C-S-H gels, which enhances the mechanical characteristics of the ECCs. The SEM analysis reveals that NS particles can act as nuclei, accelerating the crystallization process of the matrix material, leading to a denser and more homogeneous structure.
In conclusion, the two types of nanomaterials (NS and CNTs) demonstrate different effects on the compressive properties of ECC. NS performs better in enhancing compressive strength, while CNTs perform better in enhancing compressive strain. The study highlights the potential of nanomaterials to improve the mechanical properties of ECC and demonstrates the importance of understanding the microstructure of the material to optimize its performance.