## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c} \hline \hline
**Soll Type** & **Location** & **USCS** & **LL (S)** & **LP (S)** & **PI (S)** & **Improve** & **Filter Length** & **Dosis** & **k MOD** & **lc OMC** & **lc UCS** & **Observations** & **Reference** \\ \hline High plasticity day & Pakistan & CH & 77 & 36 & 41 & Wood fiber & 23-31 & 0.6 & - & - & 0.69 to 0.67 & 0.241.5m. CH flow & 3.4 to 7.5 (saturated) & [20] \\ \hline High plasticity day & Pakistan & CH & 77 & 36 & 41 & Banarus fiber & 28-66 & 1.2 & - & - & 0.69 to 0.58 & 0.311.1m. CH flow & [20] \\ \hline High plasticity day & Pakistan & CH & 77 & 36 & 41 & 0.6\%,wood fiber + & 23-31 word and 28-64 barnars fiber & - & - & - & 0.69 to 1.30 & CBR (from 3.4 to 15.4 [20]) \\ \hline High plasticity day & Saudi & CH & 74 & 39 & 35 & 15\% lower banana ash + 12\%,nano silica & 200-300 & - & - & 27.4 to 28.9 & 4.59 to 18.35 & sample, 28 days of cutting & [9] \\ \hline High plasticity day & India & CH & 84 & 29 & 55 & Fly ash & - & 30 & 1.58 to 1.42 & 25.0 to 23.0 & 2.04 to 5.40 & Better behavior & [60] \\ \hline High plasticity day & India & CH & 84 & 29 & 55 & Husa-like & - & 30 & 1.58 to 1.35 & 25.0 to 29.4 & 2.04 to 3.47 & Better behavior & [60] \\ \hline Soft clay & Indonesia & CH & 75 & 33.96 & 41.05 & 75\% cement + 25\%, bamboo load ash & - & 30 & 1.28 to 1.35 & 29.0 to 35.0 & - &
\begin{tabular}{c} CBR from 6.0 to 55 \\ (without wet) \\ \end{tabular} & [93] \\ \hline High plasticity & Philippines & MH & 64.78 & 46.85 & 18.64 & Recycled gypsum & - & 15 & 1.22 to 1.29 & 42.4 to 20 & 0.51 to 10.20 & 28 days of curing & [62] \\ \hline High plasticity day & Philippines & MH & 64.78 & 46.85 & 18.64 & 5\%, recycled gypsum & - & - & 1.22 to 1.36 & 42.4 to 34.20 & 0.51 to 12.24 & 28 days of curing & [62] \\ \hline High plasticity day & Ecuador & CH & 91 & 38 & 53 & 10\%,hav freive + 40\%, recycled ceramic & - & - & - & - & - & CBR from 8.9 to 34.6 [standard) & [42] \\ \hline Cohesive soil & Peru & CL & 37.38 & 19.55 & 17.83 & 4\%,malesse & - & - & - & - & CBR from 6.61 to 10.20 & [40] \\ \hline Cohesive soil & Peru & CL & 37.38 & 19.55 & 17.83 & 10\%,vinasse & - & - & - & - & CBR from 6.61 to 11.04 & [40] \\ \hline High plasticity day & Peru & CL & 36.24 & 21.31 & 14.93 & Husa-like & - & 10 & 1.91 to 1.67 & 18.31 & - & CBR from 5.0 to 7.10 [41] \\ \hline High plasticity day & Peru & CL & 36.24 & 21.31 & 14.93 & 10\%,hav freive ash + & - & - & 1.91 to 1.82 & 15.34 to 17.88 & - & CBR from 5.0 to 10.07 [41] \\ \hline High plasticity day & Peru & CL & 36.24 & 21.31 & 14.93 & 10\%,hav freive ash + & - & - & 1.91 to 1.82 & 15.34 to 17.88 & - & CBR from 5.0 to 10.07 [41] \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Conf. UCS is achieved by combining fly ash, alkaline activator, and coconut fiber. The maximum CBR was achieved with a mixture of cement and bamboo ash. Natural fibers alone primarily improved CBR and moderately improved UCS, while ash alone had a greater impact on UCS, especially after curing. That indicates that combinations of chemical additives and natural fibers are more effective than either alone. Combinations show the greatest overall improvement, especially in UCS and CBR. Most studies use dosages between 1% and 2% of the soil's dry weight. The greatest improvements were observed with 2% jute and palm fiber and 1% coconut fiber. The recommended dosage is 1-2% of the soil's dry weight. Natural fibers increase soil strength and ductility, making them useful for subgrade layers in sustainable road infrastructure. The Maximum Soil Density shows a decreasing compression ratio. Several authors agree that replacing soil particles with fibers decreases the weight of the soil matrix since the density of the fibers is lower than the density of the soil particles. An increasing compression ratio is observed regarding optimal moisture content, given that fibers have a greater water absorption capacity. The length of the natural fibers used with amendment materials ( coconut, palm, and jute) ranges from 15 to 280 mm.