ABSTRACT This study investigates sodium silicate (SS) solutions derived from rice husk ash (RHA) dissolved in 8 M NaOH as sustainable activators for alkali‐activated cements (AACs), compared with commercial SS. AACs were produced using a 50:50 blend of electric arc furnace slag (EAFS) and biomass bottom ash (BA). The effects of NaOH/RHA ratio (6.6–2.8) or activator modulus (Ms = 0–1.15) on gel formation and performance were analyzed by SEM‐EDS, XRD, and FTIR. Low Ms (≤0.85) or high NaOH/RHA ratios (≥4.0) hindered gel development, yielding porous microstructures and low strength. Higher Ms (≥1.0) enhanced dissolution, promoting C‐(A)‐S‐H and N‐(A)‐S‐H gels, resulting in dense matrices with strengths up to 27.9 MPa. The binary EAFS–BA system showed synergistic effects, while RHA‐based activators achieved performance comparable to SS. These results confirm RHA‐derived silicates as viable, low‐impact alternatives, emphasizing the importance of optimized activator composition for sustainable cement production.
Muñoz‐Castillo et al. (Sun,) studied this question.