Clayshale Stabilization using Portland Pozzolan Cement Type II to Increase the Shear Strength of Soil

Abstract

Abstract Clayshale soil was found 5 meters below ground level in the Hambalang area. The fragility of clay shale soil results in clay shale soil being rarely used in construction needs. The physical condition of clayshale is not optimal when it is dry and also when it is mixed with water. This research is carried out so that the cohesion value and shear strength in the clayshale is close to perfection with the stabilization process. Disturbed sampling was carried out in the Hambalang area, providing that the granules passed the 4mm filter. Tests carried out to obtain soil parameters include physical properties testing and mechanical properties testing. Based on the results of laboratory tests, the original clayshale soil has a plasticity index (IP) value of 27.07%, so clayshale soil included CL (Clay-Low plasticity) according to the USCS category. The use of Portland pozzolan cement in this study is because it has high resistance to salts and sulfuric acid. Mixing of PPC cement test materials was carried out to determine the optimal cohesion value and shear strength by mixing 5%,8%, and 11% of clayshale weight per sample. The addition of cement variations can increase the specific gravity value of the soil and the optimum moisture content, but it can reduce the dry weight value of the soil and the value of the plasticity index on clayshale soils. The cohesion values and soil shear strength obtained after Triaxial UU testing on samples with the addition of Portland pozzolan cement (PPC) increased; however, the increase that occurred was varied and significant at the time of the PPC cement mixture.