Effect of Wood Ash Admixture on Clay Soils in Atterberg Test

Expansive soils are considered as undesirable phenomena in geotechnical engineering due to their excessive volume change with seasonal moisture fluctuations. As a type of expansive soils, clay soils suffer from certain problems such as high subsidence, low shear strength and density, plasticity properties, low permeability, low strength, changes in pore water pressure, volume change and chemical structure. Thus, earthwork researchers and civil engineers have always sought to stabilize clay soils with different additives. Besides, traditional additives are being replaced with waste materials due to their economical advantage, better environmental preservation, appropriate disposal and reduced adverse effects of disposals. In this regard, we used a new waste material additive, wood ash, to stabilize clay soils and to investigate the effect of this additive on atterberg limits of clay soil specimens. Atterberg tests were performed on soil specimens stabilized with different proportions of wood ash. Tabulations and figures were used to compare the results of experiments. The soil specimens had variable primary plasticity indices of 26, 31, 35 and 39 that were mixed with different proportions of wood ash from 1-25 wt%.