STABILIZING CLAYEY SOILS OF CAMEROONS FAR NORTH REGION

Soils geotechnical and mechanic features have significant impacts in road construction. Lift tests carried on clayey soils in the Far North Region of Cameroon revealed low levels of lift values. In order to improve these values, 2%, 4% and 6% of lime and cement were added to the initial material. Trials carried out in order to measure the plasticity index, density and the CBR index of various mixes of karal and sandy clay revealed a sharp improvement of these parameters. In fact, results attained indicate that with a 6% content of binding agent, the karal-lime blend moves from 19% to 14%, and that of karal-cement from 19% to 9.7%. As far as the sandy clay-lime blend is concerned, it moves from 15.3% to 14%, and the sandy clay-cement mix from 15.3% to 10.8%. Maximum density is obtained with a binding agent content of 4%. With cement, it actually moves from 1.85t/m3 to 2.08t/m3 when karal is mixed with cement, and from 1.88t/m3 to 2.01t/m3 for the sandy clay-cement blend. For a 6% content of binding agent, karals CBR index increases from 6 to 24 for the karal-lime mix, and from 6 to 27 for that of karal-cement. With the same content of the binding agent, the CBR index of the sandy clay-lime mix moves from 13 to 39, and from 13 to 62 for the sandy clay-cement blend. This study reveals that with a 300% increase, cement has a higher impact than lime on materials used.