The paper presents the results of the second phase of a project that studies the applications of Fluid Bed Combustion (FBC) ash in soil stabilization with particular application to forest roads. Two types of applications have been identified based on different types of soils which react differently with the addition of FBC ash. The first type application corresponds to those soils whose physical and mechanical properties are improved to a certain extent with the addition of FBC ash and may be used as an improved base course or an improved gravel road. The second type of application corresponds to those soils whose physical and mechanical properties are improved to a certain extent, but above an "x" percentage of FBC ash addition, they may swell and produce an adverse effect. The research work examines different procedures to further improve the performance of the second types of soils in order to make feasible its application on secondary type of forest roads.