## 4 Results and Discussion
### XRD and SEM Analysis  
As shown in Figure 7, the XRD analysis was conducted on samples with varying zeolite powder-to-slag powder ratios (0:100, 30:70, and 50:50), CL retarder dosages (2% and 5%), and NaOH alkali activator dosages (3% and 9%). The main products of the alkali-activated GGBPS-zeolite powder grouting materials were CaSO\({}_{4}\) 2H\({}_{2}\)O, C-S-H, SiO\({}_{2}\), and CaCO\({}_{3}\). As C-(A)-S-H is an amorphous phase [43; 44], its diffraction peaks were not evident in the XRD analysis. As the dosage of zeolite powder increased from 0% to 30%, both the CaCO\({}_{3}\) and SiO\({}_{2}\) diffraction peaks increased, with a rise of 79.51% and 344.29%, respectively. When the dosage of zeolite powder reached 50%, the SiO\({}_{2}\) diffraction peaks continued to enhance, reaching a level of 76.92%, while the CaCO\({}_{3}\) diffraction peaks remained largely unchanged, increasing by only 9.46%. The findings indicated that in an alkaline environment, where all other factors remained constant, increasing the dosage of zeolite powder resulted in an increased content of unconsumed SiO\({}_{2}\). This, in turn, led to a decreased pH value of the slurry, thereby hindering the effective hydration of the gelling material. In this case, the high-energy-state aluminum-oxygen bond (-Al-O-) and silicon-oxygen bond (-Si-O-) exhibited difficulty in dissolution [45], resulting in a decline in the generated C-S-H and C-(A)-S-H cementitious hydrides. This, in turn, contributed to the gradual decrease in the compressive strength of the slurry stone bodies with increased dosage of zeolite powder. It was demonstrated that as the dosage of CL increased, the intensities of the SiO\({}_{2}\) and CaCO\({}_{3}\) diffraction peaks decreased significantly, with a degree of reduction of 12.74% and 52.70%., indicating that SiO\({}_{2}\) and CaCO\({}_{3}\) were gradually converted into other hydration products. CL, an anionic surfactant, enhances the water dispersibility of adsorbent  
Figure 7: Effects of different factors on XRD: (**a**) zeolite powder-GGBPS; (**b**) CL dosage; (**c**) NaOH dosage. materials [46]. This improvement was attributed to the ability of CL to wet the surface of the particles, thereby facilitating the hydration reaction. Furthermore, the diffraction peak intensities of the monocalcium aluminate hydration products exhibited a concomitant enhancement with increasing CL doping, showing an increase of 114.90%. This suggests that the monocalcium aluminate hydration products play a substantial role in enhancing the densification of stone bodies [47]. This was the same as the conclusion reached in Section 4.4. Keeping all other conditions constant, the strength of the stone bodies doped with 5% CL exceeded that of those doped with 2%. The SEM images of the slurry stone bodies in Figure 8 combined with Figure 6b clearly show that the compressive strength of the stone bodies was higher at a 5% CL dosage compared to 3%. The specimen with 5% CL doping had a more compact structure, fewer holes, denser gels, and stronger bonding of the gels to the skeleton. In addition to the Calcium Sulfoaluminate hydrate (C-(A)-S-H) gelation phase and Cement Silicate Hydrogel (C-S-H) gelation phase inside the stone bodies [48], the mineral backbone in the stone bodies consisted of a number of unreacted minerals such as quartz and calcite. In the presence of the NaOH alkali activator, the SiO\({}_{2}\) and Al\({}_{2}\)O\({}_{3}\) crystal structures dissolved to form aluminum-silicon complexes, which were rearranged to form a stable three-dimensional mesh structure. On the other hand, gypsum (CaSO\({}_{4}\)), the main mineral in GGBFS, reacted with NaOH and ambient CO\({}_{2}\) to form CaCO\({}_{3}\). As depicted in Figure 7c, when the NaOH dosage increased, the XRD peak area of CaCO\({}_{3}\) rose by 20.51%, accompanied by an increase in its crystal content. Moreover, the intensity of the diffraction peaks of the monocalcium aluminate hydration products also witnessed a significant growth of 226.19%.