Eco-friendly alkali-activated nano concrete: Impact of nano-GGBFS on mechanical and microstructural properties

Abstract

The production of Ordinary Portland Cement (OPC) is a significant contributor to greenhouse gas emissions, particularly carbon dioxide (CO₂), which impacts the environment. To address this issue, the construction industry is focusing on reducing CO₂ emissions while improving the strength and microstructure of concrete through the use of nanomaterials (NM). This study investigates the fresh, mechanical, and microstructural properties of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS)-based Alkali-Activated Nano Concrete (AANC) with nano Ground granulated blast furnace Slag (nGS). The results show that varying concentrations of nGS enhanced the properties of AANC, with 12 % nGS yielding the best mechanical and microstructural performance. Microstructural studies, including Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Energy Dispersive X-ray analysis (EDAX), Fourier Transform Infrared (FTIR), and Thermogravimetric Analysis (TGA), demonstrated superior geopolymerization at this optimal nGS content. The addition of nGS also reduced the setting time and increased compressive strength, leading to a denser, crack-free matrix. However, excessive nGS beyond the optimal content resulted in non-uniform distribution due to agglomeration. The findings suggest that incorporating nGS in AANC can significantly improve the performance and sustainability of construction materials. The economic analysis and Life Cycle Assessment (LCA) results collectively demonstrate the viability of nGS-enhanced AANC as a sustainable solution, offering long-term cost savings through reduced maintenance, extended service life, and energy efficiency, while significantly lowering environmental impacts across its lifecycle stages, positioning it as a high-performance and environmentally friendly alternative to traditional Portland cement-based materials.