Effectiveness of 2 Phase Stabilization Lime-Cement on High Plasticity Clay

Soil-cement has been used as an alternative of pavement materials in Indonesia since 1980. The use of local soil materials has the advantage of environmentally friendly and save the cost of transportation of pavement materials. How soil-cement reaches strength as per specification, and ease of implementation becomes a challenge of applying soil-cement stabilization as a road pavement. The addition of cement on one side will increase the soil-cement strength however it will increase the stiffness and also generate pavement crack. Several methods to improve performance and ductility of soil-cement on high plasticity clays that have been studied are: adding rice husk ash, fly ash, lime in 1 phase stabilization method and 2 phase stabilization method and adding sand to soil before cement stabilization. This paper presents the results of laboratory studies of comparison between 2 phase stabilization lime-cement method and 1 phase stabilization lime-cement method on high plasticity clay. A series of index properties and unconfined compression tests according to SNI were performed on the untreated clay, cement treated clay, and lime-cement treated clay sample that prepared using the 2 phase lime-cement stabilization method and the 1 phase lime-cement stabilization method. Lime content that was used were 2%, 6% and 10%, while the cement content was 10% of the soil dry weight. The results shows that the 2 phase stabilization lime-cement method was more effective than the 1 phase method. UCSsoaked value of the clay sample treated by lime 10 % and cement 10 % prepared using 2 phase stabilization method is 9,64 time the UCSsoaked value of the clay sample treated cement 10 % while the UCSsoaked value of the clay sample treated by lime 10 % and cement 10 % prepared using 1 phase stabilization method is 3,66 time the UCSsoaked value of the clay sample treated cement 10 %.