Parameters changes of Fibrous Peat Stabilized with [Ca(Oh)2+Flyash] and [Caco3+ Flyash]

Lime materials [CaCO3 and Ca(OH)2] had been used since years ago as stabilization materials for clay soil. For peat soil, however, was only recently developed and it was found that the lime material had to be mixed with pozolon such as Fly Ash (FA) or Rice Hush Ash (RHA) as silica material; it was because peat had no silica content. This paper presents the use of two different types of lime [CaCO3 and Ca(OH)2] mixed with Fly Ash (FA) as admixture materials, those were, Admixture-1 [30% CaCO3 dan 70% FA] and Admixture-2 [10% Ca(OH)2 dan 90% FA]. Fibrous peat soil taken from Palangkaraya, Central Kalimantan, Indonesia, was stabilized with Admixture-1 and Admixture-2 separately, and then cured in different period of time in order to see the effect of each admixture to the peat behaviour. The result shows that both admixtures absorb water in soil pores to produce silica gell (CaSiO3); Admixture-2 produces silica gell faster than the Admixture-1 because Admixture-2 is able to absorb water faster than the other one. As a result, the increament of soil perameters (unit weight, specific gravity, and soil strength) of peat stabilized with Admixture-2 faster than the one stabilized with Admixture-1; those parameters, however, then decreases caused by no more water available in the soil pores. Decreament of the stabilized peat compression is really significant, especially for peat stabilized with Admixture-2. In addition, it can be concluded that development of silica gell CaSiO3 is really depending on the availability of water in the soil pores.