The Effect of Addition of Palm Shell Ash on the Physical and Mechanical Properties of Clay Soil

— In general, construction damage often occurs because it has a low subgrade bearing capacity which is commonly found in clay soils, which are very cohesive, have low shear strength and slow consolidation process, from these problems it is necessary to carry out soil stabilization. This study aims to determine the effect of adding oil palm shell ash to clay on the value of specific gravity (Gs), plasticity index (PI), shear strength and consolidation coefficient (Cv) with variations in addition of 6%, 8%, 10%, 12 % and 14%. The soil used in this study based on the AASHTO classification was included in group A-7-5 with the clay soil, Gs value of 2.61, the PI value of 14.40%, the shear strength value of 73.19 kPa and the value of Cv at a stress of 50 kPa is 0.00502 cm2 /s, a stress of 100 kPa is 0.00315 cm2 /s, a stress of 200 kPa is 0.00224 cm2 /s and a stress of 400 kPa is 0.00127 cm2 /s. In the Gs test with the addition of palm shell ash, there was a decrease in each variation with the largest decrease in the 14% variation of 2.22 and from the PI test there was an increase to 8% variation of 23.53%. In the direct shear test, the optimum shear strength value occurs at a variation of 8% with a value of 52.60 kPa. In the consolidation coefficient there is a decrease in each addition variation with the largest decrease in the 14% variation with stress 50 kPa, 100 kPa, 200 kPa and 400 kPa of 0.00326 cm2 /s, 0.00261 cm2 /s, 0.00205 cm2 /s and 0.00167 cm2 /s