# Use of Reservoir Sediments to Improve Engineering Properties of Dune Sand in Oman
## 5 Conclusions  
The present study was conducted to investigate the possibility of improving the engineering properties of Al-Sharqia dune sand by the addition of fine reservoir sediments. As a domain of novel low carbon technologies and sustainable development, the environmental issues related to waste management of the dredged sediment and efficient resource utilization by reusing these sediments have been addressed. Samples of dune sand (classified as poorly graded sand) and sediments (classified as high plastic clay) collected from the Al-Sharqia desert and the reservoir of Wadi Jezzi dam in Oman were mixed to study their engineering properties. The sediments were added in percentages by weight of dry sand ranging from 5 to 95%. Laboratory tests such as consistency limits, void ratio, gradation analysis, compaction, and unconfined compression were performed on the binary mixtures as well on pure sand and sediment. Based on the experimental results presented in this paper, the following conclusions are drawn:  
* The sediment substantially increases the unconfined compressive strength of the treated sand. The unconfined compressive strength increases with sediment content up to 75% and decreases afterwards. The binary mixture of sand sediment is sensitive to moisture, however the order of strength stability against moisture is DSS75 > DSS50 > DSS20. * The addition of sediment in sand has improved the maximum dry density up to a treatment ratio of 50%, however, OMC increases from 17% for pure sand to 22.5% for pure sediment. The OMC shows good correlation with the plastic limit of the binary mixtures of sand and sediment. * The addition of sediment to sand has improved the uniformity coefficient of the sand to some extent with an increase in the maximum and minimum void ratios as well. * The elemental analysis of the sediment confirmed the material as non-contaminated and suitable for engineering application without causing any environmental issues. * The regression models generated from the experimental data presented in this study are in good agreement with the published literature and these empirical correlations can be considered as reliable for dune sands treated with the reservoir sediments to save time and effort involved in laboratory and field testing for engineering characterization of these materials. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Properties** & **Regression Models** & **R\({}^{2}\) Value** \\ \hline Sediment content (s) and maximum & \(\mathrm{e_{max}}=0.7732\mathrm{e^{0.0096}}\) & 0.99 \\ (\(\mathrm{e_{max}}\))/minimum (\(\mathrm{e_{min}}\)) void ratios & \(\mathrm{e_{min}}=0.4279\mathrm{e^{0.0088}}\) & 0.96 \\ \hline Sediment content (s) and Atterberg limits (Liquid & \(\mathrm{w_{L}}=0.302\mathrm{s}+21.98\) & 0.99 \\ limit, \(\mathrm{w_{L}}\) and plastic limit, \(\mathrm{w_{P}}\)) & \(\mathrm{w_{P}}=0.172\mathrm{s}+8.99\) & 0.79 \\ Sediment content (s) and Plasticity index (IP) & \(\mathrm{I_{P}}=0.13\mathrm{s}+11.99\) & 0.66 \\ \hline Sediment content (s) and compaction & \multirow{2}{*}{MDD (\(\mathrm{kN/m^{3}}\)) \(=-0.0008\mathrm{s^{2}}+0.066\mathrm{s}+16.58\)} & 0.96 \\ characteristics (Maximum dry density, MDD and & OMC(\(\%\)) \(=0.0991\mathrm{s}+12.116\) & 0.75 \\ \hline \multirow{3}{*}{Attterberg limits (\(\mathrm{w_{L}}\) and \(\mathrm{w_{P}}\)) and compaction characteristics (OMC and MDD)} & OMC (\(\%\)) \(=0.52\mathrm{(w_{L}+7.02)}\) & 0.79 \\  & OMC (\(\%\)) \(=0.87\mathrm{w_{P}}\) & 0.99 \\ \cline{1-1} characteristics (OMC and MDD) & MDD (\(\mathrm{kN/m^{3}}\)) \(=0.2\mathrm{(126.6-w_{L})}\) & 0.95 \\ \cline{1-1}  & MDD (\(\mathrm{kN/m^{3}}\)) \(=0.31\mathrm{(75.31-w_{P})}\) & 0.93 \\ \hline Sediment content (s) and unconfined compressive & \multirow{2}{*}{UCS \(=13.63^{\mathrm{e0.03348}}\)} & \multirow{2}{*}{0.94} \\  strength (UCS) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: List of important regression models developed. **Author Contributions:** Conceptualization, M.U.Q. ; methodology, M.U.Q. and M.A. ([PERSON]); validation, M.U.Q. and M.A.