## 2 Materials and Methods  
### Materials  
#### 2.1.1 Fluvial Sediment  
The sediments were dredged from the downstream section of the Rouen River Port (Rouen, Normandy, France) between kilometric point KP 260, La Bouille/Sahurs, and KP278, Duclair, as shown in Figure 1a. The dredger 'Gambe d'Amfard' operated on the Seine (Figure 1b) before delivering some of the dredged sediments either alongside the quayside in big-bag containers (Figure 1c, present study) or by discharging them for agricultural spreading (Figure 1d). They were collected in two 1 m\({}^{3}\) sealed big-bags. All the sediments were oven-dried at temperatures between 40 \({}^{\circ}\)C and 60 \({}^{\circ}\)C, crushed manually or with a knife mill and sifted with a 2 mm mesh sieve. The physical, geotechnical and chemical properties of the sediments were investigated to identify and characterize them in accordance with European standards. The nature and particle size distribution along with Afterberg limits were first determined to assess their suitability for unfired sediment-based bricks. The main values for the physical, geotechnical and chemical parameters of the sediments are given in Table 1. \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Sample** & **Rouen 1-R1** & **Rouen 2-R2** & **Rouen 3-R3-1** & **Rouen 4-R3-2** \\ \hline Clay \textless{} 2 \(\mu\)m (\%) & 1.1 & 2.6 & 11.9 & 11.7 \\ \hline Silt 2 \(\mu\)m \textless{} \% \textless{} 50 \(\mu\)m (\%) & 32.3 & 42.3 & 71.9 & 72.1 \\ \hline Sand 50 \(\mu\)m \textless{} \% \textless{} 2 mm (\%) & 66.6 & 55.1 & 16.2 & 16.2 \\ \hline LL (\%) & 41 & 36.8 & 37.9 & 37.9 \\ \hline PI (\%) & 16 & 11.0 & 13 & 13 \\ \hline OMC (\%) & 9.1 & 9.1 & 5.8 & 5.8 \\ \hline \(\rho_{\text{s}}\) (g/cm\({}^{3}\)) & 2.64 & 2.61 & 2.60 & 2.60 \\ \hline MDD (g/cm\({}^{3}\)) & 1.44 & 1.38 & 1.55 & 1.55 \\ \hline MMC (\%) & 23.0 & 22.2 & 22.0 & 22.0 \\ \hline \hline \end{tabular}  
* Note: LL = Liquid limit; PI = Plastic limit; OMC = Organic matter content; \(\rho_{\text{s}}\) = Specific weight; MDD = Maximal dry density; MMC = Maximal moisture density.  
\end{table} 
Table 1: Geotechnical data of the fluvial sediments. As shown in Table 1, the particle size distribution of the sediment depends on its preparation after drying. The Rouen R1 sample was prepared manually and graded under dry conditions. A knife mill was used and the granulometry was performed with a laser particle size analyzer under wet conditions. This reduces the size of the particles and deagglomerates them (samples R2 and R3). The longer the disintegration time with the knife mill, the finer the sediment becomes, as in the case of sample R3. Samples R3-1 and R3-2 come from batch R3 and were prepared in the same way, with two particle sizes performed (see Figure 2). These are the finest sediments obtained in this study. This will have an influence on the compaction curve. Air drying or oven drying can also lead to some changes in the compaction curve, especially in the presence of organic matter [16; 17; 18]. This can be seen in Figure 2, where the curves shift to the left from sample R1, then R2 and samples R3. The sediment is becoming finer and finer and lacks the coarser elements required to meet standards; samples R1 and R2 appear to be more suitable from a granular point of view. Plasticity also plays a role in the manufacturing of unfired bricks. Figure 1: Sediment dredging on River Seine downstream of Port of Rouen: (**a**) Dredging location between KP 260 and KP278, (**b**) Dredger “Gambe d’Amfard” on River Seine; (**c**) Sediment big-bag container on the quay at La Bouille; (**d**) Location for agricultural spreading near Sahurs village. The behavior of the water-sediment mixture is evaluated using the consistency with Atterberg limits, i.e., plasticity tests, whatever the manufacturing type (extrusion, molding or handmade).