Potential usage of fly ash and nano silica in cement mortar for a sustainable construction

Despite being a by-product, fly ash is utilized as a supplementary cementitious material. Nano-silica, sourced from rice husk ash, represents an eco-friendly material with promising potential as a substitute for cement. The applications of fly ash and nano-silica in infrastructure and civil engineering are currently restricted, and their waste mitigation efforts have yet to gain significant recognition. Through two testing programs, this study investigated the fundamental and mechanical characteristics of cement mortar integrating different dosages of fly ash and nano-silica. In the first part, fly ash was used as cement replacement at various levels of 0%, 10%, 20%, and 30% to produce the cement-fly ash mortar. Test results indicated that a mortar sample containing 10% fly ash demonstrated strength levels comparable to those of pure cement mortar after 56 days of curing. In the second part, cement was continuously replaced with nano-silica, while fly ash was constant at 20%. Results demonstrated that adding 2% nano-silica enhanced the mechanical properties of the cement-fly ash-nano silica mortar. These findings are anticipated to improve waste mitigation for fly ash and rice husk ash, reduce carbon dioxide emissions, and contribute to developing environmentally friendly materials.