## 3 Results and Analysis
### Phase Composition and Microstructure
4 displayed minimal third-stage mass loss, likely due to suppressed carbonation during curing, resulting in diminished calcite production. The TG/DSC results, corroborated by XRD analysis, collectively demonstrate that Specimen No. 11 achieved superior mechanical performance through optimized hydration product, validating its ISW proportion as the most effective composition. Figure 9 presents the particle morphology of Sample No. 11 observed using SEM. Figure 9 demonstrates a typical characteristic of aeolian sand particles encapsulated by cementitious materials. Through comparative analysis with untreated aeolian sand particles shown in Figure 1, it can be observed that a dense layer of hydration products composed of gel and ettrinigite thoroughly coats the particle surface. At 500\(\times\) magnification, neither distinct pores nor the original surface texture of soil particles can be clearly discerned; however, small and shallow pores became discernible upon magnification to 5000\(\times\). This observation corresponds to the higher gel production detected in the phase analysis of this specimen, as well as the elevated GGBFS dosage and enhanced _UCS_ observed at macroscopic scale. Figure 9 illustrates the interconnections formed between multiple soil particles through hydration products. As previously discussed, the natural aeolian sand exhibits a loose microstructure with minimal interparticle bonding under untreated conditions, resulting in load-bearing capacity that relies solely on mechanical interlocking. After stabilization using ISW-based cementitious materials, multiple particles encapsulated by gel and other hydration products gradually establish stable connections during compaction and curing processes. The matrix of these connections primarily consists of C(-A)-S-H gel, internally reinforced by crystalline phases including ettrinigite, Ca(OH)\({}_{2}\), and calcite, which collectively provide robust structural support. However, a limited quantity of unhydrated ISW particles can still be detected under high magnification, which may be attributed to the weak hydration activity of specific ISW components. These findings exhibit similarities with previously reported microstructures of cement-stabilized aeolian sand. Nevertheless, compared to the porous interparticle connections observed in cement-treated specimens, the ISW-stabilized aeolian sand demonstrates significantly denser and more compact bonding configurations. This evidence confirms that ISW cementitious materials can establish a more reliable and higher-strength microstructure at the microscopic scale. Figure 8: TG and DSC curve of specimens in SLM experiment. For comparative analysis, Figure 10 exhibits the microstructural morphologies of lower-strength specimens No. 4, 8, and 26, through which the influence of ISW proportions on the microstructure of stabilized aeolian sand can be systematically elucidated. In Figure 10a, depicting the particle encapsulation status of Specimen No. 4, it is evident that, although hydration products such as gel and ettringite were generated, the particle surfaces were merely covered by an exceedingly thin layer, leaving the significant exposure of sand particle surfaces. Upon further magnification to 10,000\(\times\), the C(-A)-S-H gel predominantly exhibited flocculent structures with limited spatial coverage and short filament lengths, cementing sparse ettringite and Ca(OH)\({}_{2}\) crystals. Unlike the integrated matrix observed in Specimen No. 13, these hydration products failed to form a continuous network, while unhydrated ISW particles were ubiquitously distributed. Such microstructural configurations resulted in feeble interparticle connections prone to external load-induced damage, ultimately manifesting as substantially reduced bearing capacity at the microscopic scale. Figure 10b illustrates the particle surface morphology of Specimen No. 8. Although the hydration product layer appeared thicker compared to Specimen No. 4, the residual exposure of sand particle surfaces was still detected.