The present study explores a cost-effective method for using activated ground granulated blast furnace slag (GGBFS) and silica fume (SF) as cement substitutes. Instead of activating them with expensive alkali solutions, the present study employs industrial-grade powdered sodium aluminate (SA) and hydrated lime (HL) as activators, reducing expenses by about 94.5% compared to their corresponding analytical-grade counterparts. Herein, the exclusivity is depicted using less pure chemicals rather than relying on reagents with 99% purity. Two mixing techniques are compared: one involves directly introducing powdered SA and HL, while the other pre-mixes SA with water before adding it to a dry powder mixture of GGBFS, SF, and HL. Microstructural analysis reveals that the initial strength results from various hydrate phases, including calcium-sodium-aluminate-silicate hydrate (CNASH). The latter strength is attributed to the coexistence of calcium-silicate hydrate (CSH), calcium-aluminate-silicate hydrate (CASH) and sodium-aluminate-silicate hydrate (NASH), with contributions from calcite and hydrotalcite. The SF content significantly influenced the formation of these gel phases. Thermogravimetric analysis (TGA) reveals phase transitions and bound water related to hydration products. The optimal mix comprises 10% SF, 90% GGBFS, 9.26% HL, and 13.25% SA, with a water-to-solids ratio of 0.45. This approach yields a compressive strength of 35.1 MPa after 28 days and 41.33 MPa after 120 days, hence suitable for structural construction.

翻译：本研究探索了一种经济高效的方法，利用活化磨细粒化高炉矿渣（GGBFS）和硅灰（SF）作为水泥替代品。不同于使用昂贵的碱溶液进行活化，本研究采用工业级粉状铝酸钠（SA）和熟石灰（HL）作为活化剂，其成本较对应的分析纯化学品降低约94.5%。本研究的特点在于使用纯度较低的化学品，而非依赖99%纯度的试剂。比较了两种混合工艺：一种是将粉状SA和HL直接引入，另一种是将SA与水预混后再加入GGBFS、SF和HL的干粉混合物中。微观结构分析表明，初始强度源于多种水化相，包括钙钠铝硅酸盐凝胶（CNASH）。后期强度归因于水化硅酸钙凝胶（CSH）、水化铝硅酸钙凝胶（CASH）和水化铝硅酸钠凝胶（NASH）的共存，并伴有方解石和水滑石的贡献。SF含量显著影响了这些凝胶相的形成。热重分析（TGA）揭示了与水化产物相关的相变和结合水。最优配合比为：10% SF、90% GGBFS、9.26% HL和13.25% SA，水固比为0.45。该方法28天抗压强度达35.1 MPa，120天抗压强度达41.33 MPa，适用于结构施工。