## 2 Materials and Methodology  
### Materials  
Four different types of soil were used in this study. The soils were chosen to be of different character and locations. Soil 1 was excavated from Gothenburg, south west coast of Sweden. Soil 2 and 3 were excavated from different depths in Sunderbyn area in Lulea, the northernmost part of Sweden.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Preparation Standards** & **Natural Soil Homogenization Method** & **Mixer Type** \\
**and Reference** & Soil is homogenized by mixing with its initial & Domestic dough mixer with a 5000 to \\ Technology, Japan [11] & water content. & 30,000 cm\({}^{3}\) mixing bowl \\ Sapienza University of Rome, Italy [12; 13; 14] & The soil is homogenized by remixing alone. & \\  & Water is added at this stage to adjust the soil & Hobart mixer \\  & water content. & \\  & The soil is homogenized by re-mixing with a & \\  & mixing speed of 136 rpm. To readjust the soil & Hobart mixer (model N50) \\ Portugal [15] & water content, water is added to the soil as a & \\  & slurry of water and binder mixture. & \\  & The soil is first homogenized thoroughly by & \\  & Society (SGS) [4; 16] & \\  & The soil is homogenized by stirred it using a & \\  &  
Soil 4 was excavated from Umea, in the north east part of Sweden. The soils were classified by tests of particle size distribution, consistency limits, loss of ignition, chemical composition, pH and specific gravity. The physical and mechanical properties are presented in Table 2. The chemical composition of the tested soils was obtained in a certified laboratory as listed in Table 3. The particle size distribution of the tested soil is shown in Figure 1. The soils were classified according to the Swedish standard. Organic content showed that organic content ranged from 2.7% to 6.8%. The soils were classified as having low to medium organic content [27; 28].  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **Soil 1** & **Soil 2** & **Soil 3** & **Soil 4** \\ \hline Soil location & Gothenburg & \multicolumn{2}{c}{Sunderbyn, Luleå} & Umeå \\ Soil conditions & Aerobic & Anaerobic (N) & Aerobic & Anaerobic \\ Depth, m & 1-2 & 1.8–2 & 0.3–0.4 & 2.7–4 \\ Particle-size distribution & & & & \\ (\%) **** & & & & \\ Fine sand (\%) (1–0.63 mm) & 29 & 4 & 15 & 10 \\ Silt (\%) (0.063–0.002 mm) & 55 & 67 & 64 & 80 \\ Clay (\%) (\(<\)0.002 mm) & 16 & 29 & 21 & 10 \\ Consistency limits (\%) & & & & \\ Liquid limit (\%) * & 37 & 95 & 48 & 45 \\ Plasticity limit (\%) ** & 20 & 37 & 32 & 35 \\ Plasticity index (\%) & 18 & 58 & 16 & 10 \\ Natural water content (\%) & 27–30 & 50 & 43–45 & 40–50 \\ Particle density & 2.69 & 2.69 & 2.67 & 2.71 \\ Loss of ignition \% *** & 4.1 & 7 & 4.8 & 2.8 \\ Bulk density (g/cm\({}^{3}\)) & & 1.51 & 1.73 & 1.76 \\ pH & 5 & 7 & 4.6 & 6.4 \\ Soil Classification & Sandy clay silt & Silty clay & Silty clay & Silt \\ Medium plasticity & Very high plasticity & Medium plasticity & Low–medium plasticity \\ \hline \hline \end{tabular}  
* Determined by the fall cone test according to Swedish standards [29]. ** Determined according to Swedish standards [30]. **** Determined according to Swedish standards [31]. **** Determined according to Swedish standards [32; 33].  
\end{table}
Table 2: Engineering properties of the four soil types.  
Figure 1: Particle size distribution of four soils type.