## 2 Overview
### Marchetti Dilatometer: Conceptualization
#### 3.1.3 Ash and Organic Content  
To know the amount of organic matter present in a sample, it is necessary to determine the percentage of dry weight remaining after having submitted it to an incineration process--this value is better known as ash content. The difference in this percentage--about 100%--is the organic content present in the sample [27; 28]. As shown in Figure 10, the results of ash content have a very well-marked tendency, as the values oscillate between 60% and 90%. Furthermore, [PERSON] et al. (2017) [29], related to the classification of peat, provides a classification of the material according to its ash content (Table 3). In addition, the ASTM D653-22 [30] mentions that to distinguish peat from organic soil, it must have less than 25% ash content by dry weight; therefore, the tabulated results corresponded to organic soils with a high ash content and an organic content ranging from 0% to 40%. Figure 10: Variation of (**a**) ash content and (**b**) organic content of each borehole about depth. Figure 9: (**a**) Organic material retained above the N°200 sieve; (**b**) fine sand retained above the N°200 sieve. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Depth (m)** & **Moisture (\%)** & **LL** & **PL** & **PI** & **Organic** & **Ash Content** & **Organic Content** & **Soil Type** \\ \hline
0–1 & 39.15 & 37.52 & 31.63 & 5.89 & No & 0 & 0 & ML, Silt with Sand \\
1–2 & 274.39 & 117.94 & 79.07 & 38.87 & Yes & 60.24 & 39.76 & OH, Organic Sandy Silt \\
2–3 & 335.72 & 320.19 & 188.22 & 131.97 & Yes & 73.10 & 26.90 & OH, Organic Sandy Silt \\
3–4 & 388.33 & 266.67 & 150.30 & 116.37 & Yes & 83.89 & 16.11 & OH, Organic Sandy Silt \\
4–5 & 489.88 & 420.82 & 248.61 & 172.21 & Yes & 59.96 & 40.04 & OH, Organic Sandy Silt \\
5–6 & 374.55 & 387.87 & 167.12 & 220.75 & Yes & 89.47 & 10.53 & OH, Organic Silt \\
6–7 & - & - & - & - & NA & - & - & NA \\
7–8 & 485.71 & 403.80 & 192.03 & 211.77 & Yes & 66.42 & 33.58 & OH, Organic Sandy Silt \\
8–9 & - & - & - & NA & - & - & NA \\
9–10 & 305.18 & 289.92 & 148.19 & 141.73 & Yes & 0 & 0 & OH, Organic Sandy Silt \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of results for the third borehole. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Depth (m)** & **Moisture (\%)** & **LL (\%)** & **PL (\%)** & **PI (\%)** & **Organic** & **Ash Content** & **Organic Content** & **Soil Type** \\ \hline
0–1 & 40.74 & 36.37 & 29.35 & 7.02 & No & 0 & 0 & ML, Silt with Sand \\
1–2 & - & - & - & - & NA & - & - & NA \\
2–3 & - & - & - & - & NA & - & - & NA \\
3–4 & 276.38 & 117.98 & 87.17 & 30.81 & Yes & 80.35 & 19.65 & OH, Organic Sandy Silt \\
4–5 & 527.32 & 381.09 & 229.54 & 151.55 & Yes & 66.17 & 33.83 & OH, Organic Sandy Silt \\
5–6 & 554.39 & 304.63 & 157.42 & 147.21 & Yes & 71.70 & 28.30 & OH, Organic Sandy Silt \\
6–7 & 520.98 & 382.52 & 263.59 & 118.93 & Yes & 69.28 & 30.72 & OH, Organic Silt \\
7–8 & 223.88 & 288.55 & 142.45 & 146.10 & Yes & 81.03 & 18.97 & OH, Organic Silt \\
8–9 & 195.91 & 191.94 & 101.88 & 90.06 & Yes & 81.12 & 18.88 & OH, Organic Sandy Silt \\
9–10 & 499.98 & 342.92 & 186.07 & 156.85 & Yes & 77.96 & 22.04 & OH, Organic Sandy Silt \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of results for the first borehole. \begin{table}
\begin{tabular}{c c} \hline \hline
**Ash Content** & **Description** \\ \hline Low ash & \textless{}5\% ash \\ Medium ash & \textless{}15\% ash \\ High ash & \textgreater{}15\% ash \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Soil classification according to ash content, [29].