The paper presents the results of investigation on stabilization of ash-slag from dumping site of “Kraków” Power Plant using hydraulic binders Terramix F22.5 or Solitex. Compressive strength of samples without and with addition of 3, 6 and 8% of binder after 7, 14, 28 and 42-days of samples maturing and after 28-days of freezing and thawing cycles were determined and on that basis the frost resistance index was calculated. The obtained tests results were compared with the results of the earlier tests of the material from the same dumping site stabilized with cement or lime. The analysis results were compared to the standard values and the usability of the stabilized ash-slag in road building was assessed.