## 2 Materials and Method
### Specim Preparation
Montmorillonite clay minerals typically possess some degree of structural disorder and contain poor crystalline phases that can provide reactive silica and alumina for pozzolanic reactions when exposed to the high pH environment created by lime addition (pH 12.1 as shown in Table 1). The alkaline conditions facilitate the dissolution of silica and alumina from the clay structure, enabling their reaction with available calcium ions to form cementitious compounds such as calcium silicate hydrate (C-S-H) and calcium aluminate hydrate (C-A-H) gels. The experimental program investigated lime-cement stabilization effects on clay soil through thirty distinct mixture compositions. Cement content was tested at five levels (0%, 2%, 4%, 6%, 8%) and lime content at six levels (0%, 5%, 10%, 15%, 20%, 30%) by dry weight of soil, with soil content calculated as the complement (100% minus combined stabilizer percentages). All thirty (30) mixtures underwent identical procedures with specimens cured for 7, 14, and 28 days at controlled ambient temperature (22 \({}^{\circ}\)C). Following each curing period, specimens were subjected to physical property tests, one-dimensional consolidation tests, and unconfined compressive strength tests. This design evaluated all combinations of cement content, lime content, and curing time for specified geotechnical properties. \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Property** & **Soil** & **Lime** & **Cement** \\ \hline \multicolumn{4}{c}{General Properties} \\ \hline Color & Brown & White & – \\ \hline Specific Gravity & 2.53 & 2.36 & 3.13 \\ \hline pH & 5.31 & 12.1 & 13 \\ \hline \multicolumn{4}{c}{Composition/Gradation} \\ \hline Gravel/Sand/Silt + Clay (\%) & 0/25.9/74.1 & – & – \\ \hline Dominant Clay Mineral & Montmorillonite & – & – \\ \hline \multicolumn{4}{c}{Engineering Properties} \\ \hline Liquid Limit/Plastic Limit/Plasticity Index/Linear & 66/24/42/18.52/71.1 & – & – \\ Shrinkage/Free Swelling (\%) & & 6/24/42/18.52/71.1 & – \\ \hline Optimum Moisture (\%)/Max Dry Density (kN/m\({}^{3}\)) & 21/16.7 & – & – \\ \hline UCS (kPa) & 0.779 & – & 29.1 (3 days) \\ \hline CBR (unsoaked, \%) & 8.2 & – & – \\ \hline \multicolumn{4}{c}{Material-Specific Properties} \\ \hline USCS Classification & CH & – & – \\ \hline Melting point/Boiling point (\({}^{\circ}\)C) & – & 2547/2894 & – \\ \hline Fineness (\(\mu\)m) & – & 368 & 362 \\ \hline Setting Time (min) & – & – & 33.4 (Initial)/242 (Final) \\ \hline Bulk Density (kg/m\({}^{3}\)) & – & 555 & 1101 \\ \hline Soundness (mm) & – & – & 0.38 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative summary of key physical, chemical, and engineering properties of soil, lime powder, and cement. The experimental protocol for evaluating the geotechnical properties of lime- and cement-stabilized clay soil involved rigorous specimen preparation and testing methodologies adhering to ASTM standards. For unconfined compression testing, specimens were meticulously positioned within the loading frame to ensure axial alignment, with deformation and load data captured continuously at a constant strain rate to generate stress-strain relationships and determine unconfined compressive strength. Consolidation testing required precise trimming of specimens to fit consolidation rings, minimizing structural disturbance, followed by incremental loading in a consolidometer. Primary consolidation completion for each load increment was assessed via the log-time method, with vertical displacement measurements enabling the calculation of consolidation parameters such as compression index, coefficient of consolidation, and preconsolidation pressure. Specim preparation for both test types involved homogenizing dry soil with stabilizing agents (lime or cement) using a mechanical mixer for a standardized duration to ensure uniform distribution, followed by incremental water addition to achieve optimal moisture content for compaction.