Impact of precursor materials and activator interactions on the microstructural and mechanical properties of one part...

The practical implementation of alkali activateds is frequently constrained by the complexities associated with preparing alkaline solutions. The advent of one-part alkali activated concrete presents substantial advantages over conventional two-part systems by negating the need for a separate activation process. This simplification not only enhances consistency, workability, and sustainability but also minimizes mixing errors, thereby facilitating broader adoption in construction applications. This study comprehensively examines the effects of various activators on the mechanical properties and microstructural characteristics of one-part alkali activated concrete. Utilizing Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDAX), we investigate the elemental compositions and microstructural features of the alkali activated samples. Our findings underscore the pivotal role of both precursor materials and activator selection in determining hydration products and overall material performance. Notably, the slag-only alkali activated exhibited a dense microstructure characterized by the formation of calcium-aluminum-silicate-hydrate (C-A-S-H) and sodium-aluminum-silicate-hydrate (N-A-S-H) gel phases. The addition of bentonite introduced a more heterogeneous microstructure, with elevated aluminum content indicative of a complex N-A-S-H structure. Furthermore, the choice of activator markedly influenced hydration reactions. The optimal ternary activator (6:3:1 Na-silicate: Na-hydroxide: Na-carbonate) achieved 47 MPa compressive strength, reducing CO₂ emissions by 80% compared to OPC [8]. This research provides critical insights for optimizing alkali activated concrete formulations, highlighting the significance of precursor materials and activator interactions. By advancing the understanding of one-part alkali activateds, this study establishes a foundation for innovative and sustainable solutions in building engineering, addressing practical challenges while enhancing the performance of construction materials.