## 3 Consolidation Properties  
### Effects of Line-Cement Stabilization on the Void Ratio and Porosity of the Clay Soil  
The void ratio and porosity are fundamental parameters that directly influence the microstructural density and mechanical performance of stabilized soil systems (Figure 5a,b). Lower values of both parameters indicate enhanced soil densification and improved engineering properties [31]. The experimental results demonstrate consistent reductions in both void ratio and porosity with increasing cement and lime contents. The void ratio decreased from 0.60 in untreated soil to a minimum of 0.25 at 6% cement and 15% lime content, while porosity declined from 0.38 to 0.19 at the same optimal combination. This synchronized reduction confirms the effectiveness of lime-cement stabilization in achieving maximum soil densification. These reductions result from pozzolanic reactions between  
Figure 4: Research progresses from material preparation through testing and analysis to final optimization.  
cemetitious materials and clay minerals, generating calcium silicate hydrate (C-S-H) and calcium aluminate hydrate (C-A-H) gels that progressively fill interstitial spaces within the soil matrix. At the optimal combination of 6% cement and 15% lime, the synergistic interaction between these binders achieves maximum efficiency in particle rearrangement and gel formation. Beyond this optimal threshold, both parameters exhibit slight increases, with the void ratio rising to 0.28 and porosity to 0.22 at 20% lime and 8% cement content. This over-stabilization phenomenon suggests that excessive cementitious agents disrupt efficient particle packing arrangement, indicating a critical equilibrium threshold where the balance between chemical reactivity and physical microstructural interactions becomes compromised. This effect may result from excess hydration products creating additional voids or preventing optimal particle arrangement, thereby diminishing the overall densification efficiency of the stabilization process.  
The lime-cement system's exceptional void ratio reduction (0.60\(\rightarrow\)0.25, 58%) and porosity decrease (0.38\(\rightarrow\)0.19, 49.5%) at 6% cement + 15% lime substantially outperforms most pozzolanic additives, with fly ash achieving only 20-40% void ratio reductions at 15-30% replacements (final void ratios 0.45-0.50) and rice husk ash reaching 30-50% reductions (void ratios 0.40-0.45) due to limited pozzolanic reactivity [32]. Ground granulated blast furnace slag (GGBFS) demonstrates comparable performance with 30-50% void ratio reductions achieving final values of 0.30-0.35, though requiring extended curing periods (28-91 days) versus the lime-cement system's 28-day effectiveness [33]. Silica fume's ultrafine particles achieve similar 40-60% reductions (void ratios 0.25-0.30) at 5-10% dosages, matching lime-cement performance but with significantly higher costs and dosage sensitivity [34]. Advanced materials including metakaolin and geopolymers surpass lime-cement systems with 50-70% void ratio reductions (final values 0.20-0.25) [35], though requiring complex alkali activation and controlled curing conditions that limit field applicability [36]. The lime-cement system's superior performance over single admixtures stems from synergistic flocculation-hydration mechanisms, with combined systems like 20% FA + 30% GGBS achieving 65% reductions, highlighting the potential for hybrid lime-GGBS or cement-SF combinations to further enhance densification [37]. However, the observed over-stabilization phenomenon at 20% lime + 8% cement, where void ratio increases to 0.28 and porosity to 0.22, mirrors literature findings where excess binders create secondary voids and disrupt particle rearrangement, emphasizing the critical importance of optimized dosages (15% lime, 6% cement) to maintain peak densification while avoiding microstructural disruption that compromises soil improvement effectiveness.  
Figure 5: Trends analysis of lime-cement stabilized soil: (**a**). Void ratio, and (**b**). Porosity.