## 2 Materials and Methodology
### Materials
Figure 3: Grading curve of soil samples from traditional rammed earth houses from the area of eastern Croatia [28]. Since Afterberg's limits also affect the suitability of the soil for the construction of rammed earth houses, they were tested according to HRN EN ISO 17892-12 [34]. The liquid limit of the previously prepared sample, where the largest grain was 0.425 mm, was tested with a fall cone test (80 g/30\({}^{\circ}\) cone). The plastic limit was tested by hand-rolling the part of the sample prepared for the liquid limit test. The liquid limit determined for basic cohesive soil is 37.4%, while the plastic limit is 21.1%, which is in accordance with the recommendations given in the literature [4; 5; 8; 9]. The stated values are also close to the values of the liquid and plastic limits of samples collected from rammed earth houses in eastern Croatia [35]. Additionally, the particle density of locally available soil, sand and gravel was tested with the fluid pycnometer method according to HRN EN ISO 17892-3 [36]. Lime density \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**ID** & \(D_{10}\) & \(D_{30}\) & \(D_{50}\) & \(D_{60}\) & \(C_{\mathbf{u}}\) & \(C_{\mathbf{z}}\) \\ \hline ALJ-1 & N/A & 0.021 & 0.046 & 0.061 & N/A & N/A \\ ALJ-2 & 0.0058 & 0.031 & 0.116 & 0.291 & 49.78 & 0.58 \\ BB-1 & 0.0022 & 0.013 & 0.030 & 0.064 & 29.68 & 1.19 \\ KR-3 & 0.0015 & 0.018 & 0.157 & 0.372 & 252.47 & 0.56 \\ KR-4 & 0.0030 & 0.023 & 0.129 & 0.302 & 100.78 & 0.59 \\ LG-1 & N/A & 0.009 & 0.018 & 0.024 & N/A & N/A \\ ZM-3 & N/A & 0.017 & 0.035 & 0.061 & N/A & N/A \\ M1 & N/A & 0.010 & 0.048 & 0.055 & N/A & N/A \\ M2 & 0.0065 & 0.052 & 0.200 & 0.297 & 45.71 & 1.40 \\ M3 & 0.0061 & 0.024 & 0.277 & 0.428 & 69.81 & 0.21 \\ M4 & 0.0028 & 0.021 & 0.129 & 0.533 & 189.21 & 0.30 \\ \hline \hline \end{tabular}  
* **NOTE:**\(D_{10}\) is the particle size, such that 10% of the particles are smaller than this size. \(D_{30}\), \(D_{50}\) and \(D_{60}\) are defined in a similar way. \(C_{\mathbf{u}}\) is the coefficient of uniformity, and \(C_{\mathbf{z}}\) is the coefficient of curvature. \(D_{10}\) is also defined as the effective size.  
\end{table} 
Table 2: Grading parameters of traditional and reproduced mixtures. Figure 5: Cereal straw and hemp fibers used for mixtures M7–M11. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**ID** & **Gravel /\%** & **Sand /\%** & **Silt /\%** & **Clay /\%** & **Additional Information** \\ \hline M1 & 0.63 & 2.66 & 79.71 & 17.00 & - \\ M2 & 8.60 & 52.77 & 33.23 & 5.40 & - \\ M3 & 10.82 & 46.67 & 37.34 & 5.17 & - \\ M4 & 21.59 & 29.58 & 40.53 & 8.30 & - \\ M5 & 21.59 & 29.58 & 40.53 & 8.30 & 4\% lime \\ M6 & 21.59 & 29.58 & 40.53 & 8.30 & 8\% lime \\ M7 & 21.59 & 29.58 & 40.53 & 8.30 & 0.25\% barley \\ M8 & 21.59 & 29.58 & 40.53 & 8.30 & 0.25\% oat \\ M9 & 21.59 & 29.58 & 40.53 & 8.30 & 0.25\% wheat \\ M10 & 21.59 & 29.58 & 40.53 & 8.30 & 0.25\% rye \\ M11 & 21.59 & 29.58 & 40.53 & 8.30 & 0.25\% rimp \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Composition of observed mixtures. was tested using petroleum instead of distilled water in pycnometers. The particle density of mixture M1 was 2.67 g/cm\({}^{3}\); for M2, it was 2.7 g/cm\({}^{3}\); and for M3, it was 2.71 g/cm\({}^{3}\), while for the remaining mixtures, it was 2.65 g/cm\({}^{3}\) (for mixtures M7-M11 without natural fibers).