Hydration behavior of Portland pozzolana cement in the presence of nano-silica

The construction industry is consistently seeking innovative approaches to diminish carbon footprints by substituting ordinary Portland cement, which has a high carbon footprint, with alternative, low-carbon materials. Portland pozzolana cement, a blend of Portland cement and fly ash, can play a crucial role in the construction sector in reducing the overall carbon footprint, as Portland pozzolana cement has a 30–35% lower carbon footprint than ordinary Portland cement. Using Portland pozzolana cement is less preferred as it has a longer setting time and lower early strength development, resulting in high costs and extended construction time, even though Portland pozzolana cement offers higher durability. To address setting time and early strength challenges, nano-silica is incorporated into commercially available Portland pozzolana cement in different amounts (1%, 2%, 3%, and 5%). Adding nano-silica to Portland pozzolana cement enhances the cement's setting time and strength performance. This study elucidates the relationships between nano-silica and fly ash within cementitious matrices. Computer modeling of hydration has been employed to explore the mechanism of action of nano-silica during the hydration process of Portland pozzolana cement. The findings indicates that 3% nano-silica accelerates the hydration process, leading to faster setting times and improving early-age strength development. In addition to lowering the carbon footprint in construction, it helps the country's economic development and sustainability goals and provides solutions for fly ash disposal or landfilling concerns. This paper uses different test methods to understand the hydration mechanism of Portland pozzolana cement in the presence of nano-silica and establish that Portland pozzolana cement is more sustainable than ordinary Portland cement.