Ground granulated blast-furnace slag (GGBS) could be used as a potential low-carbon binder when activated by a moderate activator. The use of seawater in producing construction materials has increasingly attracted attention in some coastal engineering with scarce freshwater. This study aims at studying the impact of quicklime proportions on the mechanical behavior and microstructure of the binder. The mechanical behaviors were investigated through unconfined compression tests. The hydration kinetics and microstructure characteristics were examined using XRD, TGA, FTIR, and SEM-EDX. The results indicated that the hydration heat and exothermic peaks enhanced with the quicklime proportion. The exothermic peaks were observed in the first few minutes and 4–18 h. The quicklime-GGBS pastes generated the highest UCS (>18 MPa) occurred at a quicklime proportion of 0.15. The platy-like portlandite, fibrous calcium silicate hydrate (CSH), needle-like ettringite (AFt), and Friedel's salt (Fs) were detected in XRD and SEM. The Cl⁻ in seawater promoted the formation of Fs. The XRD peaks of CSH and AFt/Fs raised and then descended with the quicklime proportion, and reached the maximum at the quicklime content of 0.15. The mass percentage of CSH and AFt/Fs from TGA first increased and then became stable when the quicklime content was 0.1–0.15. The number of amorphous GGBS particles and pores decreased under the quicklime proportion of 0.05–0.15, while the portlandite increased as the quicklime content changed from 0.15 to 0.3. Overall, the quicklime-GGBS binder could provide a potential sustainable construction material in waste recycling and freshwater saving.

当通过适度的活化剂活化时，磨碎的粒状高炉矿渣 (GGBS) 可用作潜在的低碳粘合剂。在一些淡水稀缺的沿海工程中，利用海水生产建筑材料越来越受到关注。本研究旨在研究生石灰比例对粘合剂的机械性能和微观结构的影响。通过无侧限压缩试验研究力学行为。使用 XRD、 TGA 、FTIR 和 SEM-EDX检查水合动力学和微观结构特征。结果表明，水化热和放热峰随生石灰比例的增加而增强。在最初的几分钟和 4-18 小时内观察到放热峰。生石灰-GGBS 糊产生的最高UCS (>18 MPa) 发生在 0.15 的生石灰比例。在XRD和SEM中检测到片状硅酸盐、纤维状水合硅酸钙(CSH)、针状钙矾石(AFt)和弗里德尔盐(Fs)。氯^-在海水中促进了 Fs 的形成。CSH和AFt/Fs的XRD峰随着生石灰比例的升高先升后降，在生石灰含量为0.15时达到最大值。当生石灰含量为0.1~0.15时，TGA中CSH和AFt/Fs的质量百分比先升高后趋于稳定。在生石灰比例为 0.05~0.15 时，无定形 GGBS 颗粒和孔隙的数量减少，而硅酸盐随着生石灰含量从 0.15 变为 0.3 而增加。总体而言，生石灰-GGBS 粘合剂可以为废物回收和节约淡水提供潜在的可持续建筑材料。