ABSTRACT

The condition of residential houses and road infrastructure in Taman Sari Village, Probolinggo Regency, Indonesia, has experienced considerable damage due to expansive soil. This study aims to improve the index properties, compaction, and expansion index of expansive soil through stabilization using cement and bottom ash. The cement percentage was fixed at 10% with bottom ash variations of 10%, 20%, and 30%. All tests were conducted based on Indonesian National Standards (SNI) and the American Society for Testing and Materials (ASTM). The test results showed that as the percentage of bottom ash increased, the values of index properties, compaction, and expansion exhibited improvement. The plasticity index of the soil decreased, the maximum dry density increased, and the expansion level decreased. The composition of 10% cement and 10% bottom ash was able to reduce the expansion index of expansive soil by 83.85% at a curing period of 7 days. With higher percentages of BA mixture, the stabilized soil did not exhibit an expansion index.