COMPARATIVE STUDY OF THE CHEMICAL AND MECHANICAL PROPERTIES OF CLAYS OF TWO REGIONS OF NIGER: NIAMEY AND DIFFA

This article deals with the determination of the physical and chemical characteristics of the lands of eight (8) quarries in Niger; seven (7) of these quarries are located in the region of Diffa and the eighth in the region of Niamey. The properties studied are: particle size, water content, compressive strength and water permeability. We have also carried out a study of the stabilization and the CBR in the particular case of the land of Saga. The compressive strengths obtained for the lands of Diffa region vary between 8.4 and 25 bar. The compressive strength of the earth of Saga in the region of Niamey is estimated at 57 bar. At the end of the stabilization of the land of Saga, the mechanical strength of bricks made by this land have grown strongly. The binders used are: peanut hull, sheep's wool, rice straw, glume and cow dung. The greatest resistance was obtained with the 1% cow dung mixture. Using a 12% cement ratio, the CBRs at 56.25 and 15 counts gave respective indices 40.33 and 26.6. These results show the possibility of using this stabilized soil in place of laterite or gravel for basecoats and basements of homes or for embankments of roads. We have also studied the effect of stabilizers on the permeability of this earth. Experimentation shows that this land is a water resistant. This resistance was reinforced by the presence of binders and the use of the compression press which allowed its compaction. In the natural state, the permeability of the land of Saga is 1.8 m/s. Measurements of this same permeability were made by mixing this soil, in turn with cement, rice straw, cow dung, hay and peanut hull at various percentages to determine the optimum mechanical resistance. The results obtained for the permeability range between 1.03 m/s and 2.4 m/s.