Engineering properties of hydrated lime – pond ash treated peat soil

Peat soil stability very difficult to predictable because has properties very weak strength, low compressibility, and high-water level. This study investigated the performance and trend of treated peat soil with mixture of hydrated lime (HL) and pond ash (PA). The study was to determine the physical properties of peat soil and the engineering properties of treated peat soil using the mixture of HL and PA by conducting the Unconfined Compressive Strength (UCS) test (0-, 14- and 28- days), Unconsolidated Undrained (UU) test (0-, 7-, 14-, and 21- days) and permeability test (0-, 30-, 60- and 90- days). The methods UCS test used in this study were 10% of constant of PA mix together with three types of percentages of HL (2, 4 and 8%), while the UU test method were used for peat mixture with 12%HL+20%PA. The falling head permeability test method were used for peat mixture with 12% of constant HL with 5, 10, 15 and 20% of PA respectively. Based on the results, the moisture content was in the range 461 – 856%, and the degree of decomposition of soil as H3 – H6. Samples of 8% HL and 10% PA soaked at 28- days increase the performance of strength compare with the natural soil. While, through the falling head permeability method, the coefficient performance reduces when increasing the percentage of HL and PA. It is show that, PA and HL have cementitious process which is bondage with the soil. It interacts with some soil pores and blocks the flow of water in the soil. With reducing the flow water in the soil, its same can reducing the percentages of water in soil that currently affected the movement of the soil.