This article describes physicochemical interactions of different natural clayey soils with oil-shale fly ash (OSFA) from thermal power plants, dealing with the strenghtening processes of new materials. Toward this end, a range of traditional and modern research method were used. i.e., definition of the ultimate strength under uniaxial compression and rupture by the Brazilian method, temporary changes in moisture content and linear deformation. on, it,ater and frost resistance, free CaO and SO3, CaCO3, XRD, and SEM. It was established that the surfaces of the initial component (OSFA and soils) particles were dissolved in porous alkaline solutions. The dissolution products gave rise to new amorphous and crystal formations. After 28 days, the strength of the samples reached 2-12 MPa but, after 90 days, it rose to 4-31 MPa. It was found that the strength at every stage of hardening can be increased significantly by. changing the proportion of the initial mixtures composition. The materials displayed very high water andfi-ost resimince, with coefficients equaling or exceeding the 1.0 level. except the OFSA and loess combination. The materials developed are applicable for the construction of roads, airfields, and dam bases and for various types of foundations without traditional binders, such as cement, and without heating.