BEHAVIOR OF SALINE SOIL STABILIZED WITH POLYPROPYLENE FIBER AND CEMENT

Abstract

This research deals with a problematic saline soil, which is widespread in many cities of the world, and try to obtain a solution for the reduction in its strength due to soaking by using more than one additives. In order to improve saline soil and to explain its effect, more than one additive were used in the research; polypropylene fiber is the major additive, which was used with cement in different percentages. Soil strength parameters were assessed by conducting direct shear test for both the natural and treated soil, which were tested under soaked condition after, submerged in water for 24 hour. The result of direct shear test showed that, for natural soil, there are large lose in the strength of soaked soil compared to that of dry soil due to the solubility of salt in soil. This decay in soil strength about (48.6%) for cohesion and (67.8%) from angel of internal friction. Meanwhile, with adding PPF to soil and under soaked state, the soil strength parameters grew significantly with the increase in the rate of fiber, where both the soil cohesion and angel of internal friction increase. Soils, treated with (1.5%) polypropylene fibers as well as cement, their strength parameters improved significantly as cement amount increases, where the soil cohesion and angel of internal friction increase. From experimental model which is built up to study and examine the laboratory result under complete submerged state, has a result for natural and treated soil showed improvement in bearing capacity of treated soil about 10 times compared to natural soil bearing capacity when tested under soaked condition.