# Effect of Various Proportions of Rice Husk Powder on Swelling Soil from New Cairo City, Egypt
## 4 Conclusions  
The study provides a soil stabilization method by replacing it with RHP at the ratio of 5%, 10%, 15%, 20%, and 25%. The RHP could be argued as an efficient agent for improving the properties of swelling soils. The current study concluded that the ideal ratio of RHP stabilizers is 15%. This percentage is very useful for inhibiting soil expansion. In contrast, mineralogical studies of X-ray diffraction analysis showed that sediments in the study area are comprised of montmorillonite and kaolinite. The montmorillonite in the soil indicates the swelling potential and is not allowed to direct the foundations above it. The LL of the stabilized soil is decreased from 92% for parent soil to 89.5%, 87%, and 85% partial replacement of soil with RHP, 5%, 10%, and 15%, respectively. The PL of the stabilized soil has increased from 36% for parent soil to 53.8%, 61%, and 80.5% for the partial replacement of the soil by 5%, 10%, and 15% RHP, respectively. The PI was reduced with the increase in RHP from 56% (high plasticity) to 4.5% (low plasticity). This decrease in plasticity rate indicates that the soil is improving. The SP of the stabilized soil is decreased from 1003 kN/m\({}^{2}\) for parent soil to 800 kN/m\({}^{2}\), 653 kN/m\({}^{2}\) and 489 kN/m\({}^{2}\) for the partial replacement of the soil by 5%, 10%, and 15% RHP respectively. The S of the stabilized soil is decreased from 48% for parent soil to 45.5%, 44.7%, and 34.6% partial replacement of soil  
Figure 9: Result comparison with existing literature with different percent of RHP. (**A**) Liquid limit, (**B**) Plastic limit, (**C**) Plasticity index, (**D**) swelling potential.  
with RHP 5%, 10%, and 15%, respectively. According to the above study, it is clear that RHP can be used as a soil stabilizer. The stabilization process has proven to be a fiscally efficient and environmentally efficient solution for such large and important construction works. The results of the laboratory tests highlight the need for a thorough study of the characteristics of clay soils if they are to be used in road construction work.  
This study recommends further investigation through triaxial CD tests under monotonous and cyclic loading to expand our understanding of the effect of RHP on pore pressure, permeability, and cyclic behavior.  
Conceptualization, M.A.H.S. and A.E.O.; methodology, M.A.H.S. and A.E.O.; software, M.A.H.S. validation, M.Y.H. and A.E.; formal analysis, M.A.H.S. and A.E.O.; investigation, M.A.H.S. and M.Y.H.; resources, M.A.H.S. and A.E.O.; data curation, A.E.O. and M.Y.H.; writing--original draft preparation, M.A.H.S. and A.E.O. and M.Y.H.; writing--review and editing, M.A.H.S., M.Y.H. and A.E.; visualization, M.A.H.S. and A.E.O.; supervision, A.E.O. and A.E.; project administration, M.A.H.S. and A.E.O.; funding acquisition, A.E. All authors have read and agreed to the published version of the manuscript.  
The APC was covered by \"Dunarea de Jos\" University of Galati, Romania.  
Not applicable.  
The data that support the findings of this study are available from the corresponding authors.  
The author AE acknowledges the support of \"\"Dunarea de Jos\" University of Galati, Romania, for APC support.  
The authors declare no conflict of interest.