Utilization of Lime Sludge Activated by Salt in Egyptian Expansive Soil Improvement

Abstract

Expansive soils are active clays which cause engineering problems all over the world. This research deals with the impact of lime sludge (LS) as industrial solid waste from sugar-cane factory and sodium chloride salt (NaCl) on engineering properties of expansive soil. In this research, an analytical study of chemical and physical properties of Egyptian expansive soil in Sixth of October City was made as a case study. The laboratory results showed improvement of chemical, microstructural properties and thus the engineering properties of this soil. The results of chemical analysis showed the ability of soil to improve pH; soil alkalinity raise to the required level of stabilization. After soil treatment, Microstructure scanning electron with energy dispersive spectroscopy (SEM-EDX) analyses showed that new cementitious compounds are formed and soil was changed from a weak dispersed structure to strong flocculated structure. It was also observed by increasing LS and NaCl concentrations the plastic limit increased and the liquid limit decreased, hence decreased plasticity index; the rate of soil free swelling is decreased due to change of expansive soil texture. Therefore, lime sludge activated by NaCl has positive effects on engineering properties of soil. By this way we protect the environment from industrial solid wastes.