Enhancement of Clay Compressibility and Strength Using Nano Magnesium Oxide

Civil Engineering Department, University of Technology, Baghdad, Iraq

^a* Corresponding author areejsadiq10@gmail.com
^b myf_1968@yahoo.com
^c mohammad_aswaad@yahoo.com

Abstract

In order to satisfy the requirements of environmentally friendly construction projects and minimize greenhouse gas emissions, it was necessary to focus on utilizing nanomaterials instead of conventional materials to enhance clay soils; nano Magnesium Oxide was suggested for this study. The compression and unconfined compressive strength tests were achieved to assess the compressibility behavior and strength of silty clay treated using nano magnesium oxide. Additionally, an investigation into the alteration of the clay microstructure was conducted using field emission scanning electron microscopy (FE-SEM) tests. The silty clay utilized in this research is characterized by a compression index 0.23 and an undrained shear strength of 53 kPa. The soil was treated by adding different percentages of nano-MgO (0.4%, 0.5%, 0.6%, and 0.8%), and the curing period was seven days. The treated soil samples were prepared based on the optimal water content and maximal dry density of the natural soil. The results indicate that utilization of nano Magnesium Oxide leads to a reduction in both values of the index of compression (Cc) and recompression index (Cr), in addition to a decrease in the value of the coefficient of compressibility (av). Also, the test finding for unconfined compressive strength demonstrates a noticeable increase in strength as the percentage of nano-MgO increases, accompanied by a reduction in failure strain. Adding 0.6% (the optimum percentage) of nano Magnesium oxide enhances the strength by about 114% and decreases the value of the compression index by about 36% compared with natural soil.