Comparative Analysis of Nano Zinc Oxide, Nano Silica Fume, and Nano Marble Powder as Cement Replacements in Self-Compacting Concrete

Abstract

Self-compacting concrete (SCC) is an advanced class of concrete that offers significant advantages in terms of constructability and quality. However, achieving an optimal balance between mechanical performance and durability remains challenging. This study investigated the effects of incorporating nano zinc oxide, nano silica fume, and nano marble powder as partial replacements of cement on the fresh, mechanical, and durability properties of SCC. Ten SCC mixtures were prepared, including a control mix and nine nano-modified mixes with varying replacement levels. Nano zinc oxide was used at replacement ratios of 0.5%, 1.0%, and 1.5%, whereas nano silica fume and nano marble powder were incorporated at 1%, 2%, and 3% replacement levels. The fresh properties of SCC were evaluated to ensure compliance with self-compacting requirements, whereas the hardened performance was assessed through compressive strength (CS), splitting tensile strength (TS), and flexural strength (FS) tests at 7 and 28 days. In addition, sorptivity was measured at 28 days to evaluate the durability-related performance. The results demonstrated that the incorporation of nanomaterials significantly influenced the performance of SCC depending on the type and dosage of the nanomaterial. Nano silica fume exhibited the most pronounced improvement in both mechanical strength and durability, with an optimum replacement level of 2%, achieving notable enhancements in compressive, tensile, and FSs, and the lowest sorptivity values. Nano zinc oxide provided moderate but consistent improvements in mechanical properties; however, it increased sorptivity at higher dosages. In contrast, the nano marble powder primarily acted as an inert filler, resulting in moderate strength enhancement and improved durability at low replacement levels, whereas excessive replacement led to marginal performance gains. Overall, the findings highlight the critical role of nanomaterial selection and dosage optimization in enhancing SCC performance.